Volatility-resolved source apportionment of primary and secondary organic aerosol over Europe

NASA Astrophysics Data System (ADS)

Skyllakou, Ksakousti; Fountoukis, Christos; Charalampidis, Panagiotis; Pandis, Spyros N.

2017-10-01

A three-dimensional regional chemical transport model (Particulate Matter Comprehensive Air Quality Model with Extensions, PMCAMx) was applied over Europe combined with a source apportionment algorithm, the Particulate Source Apportionment Technology (PSAT), in order to quantify the sources which contribute to the primary and secondary organic aerosol (OA) during different seasons. The PSAT algorithm was first extended to allow the quantification of the sources of OA as a function of volatility. The most significant OA sources during May were biogenic, while during February residential wood combustion and during September wildfires dominated. The contributions of the various sources have strong spatial dependence. Wildfires were significant OA sources (38% of the OA) for Russia during September, but had a much lower impact (5%) in Scandinavia. The above results are in general consistent with the findings of the CARBOSOL project for selected sites in Europe. For remote sites such as Finokalia in Crete, more than 90% of the OA has undergone two or more generations of oxidation for all seasons. This highly processed oxidized OA is predicted to also dominate over much of Europe during the summer and fall. The first generation SOA is predicted to represent 20-30% of the OA in central and northern Europe during these photochemically active periods.

Size-segregated aerosol in a hot-spot pollution urban area: Chemical composition and three-way source apportionment.

PubMed

Bernardoni, V; Elser, M; Valli, G; Valentini, S; Bigi, A; Fermo, P; Piazzalunga, A; Vecchi, R

2017-12-01

In this work, a comprehensive characterisation and source apportionment of size-segregated aerosol collected using a multistage cascade impactor was performed. The samples were collected during wintertime in Milan (Italy), which is located in the Po Valley, one of the main pollution hot-spot areas in Europe. For every sampling, size-segregated mass concentration, elemental and ionic composition, and levoglucosan concentration were determined. Size-segregated data were inverted using the program MICRON to identify and quantify modal contributions of all the measured components. The detailed chemical characterisation allowed the application of a three-way (3-D) receptor model (implemented using Multilinear Engine) for size-segregated source apportionment and chemical profiles identification. It is noteworthy that - as far as we know - this is the first time that three-way source apportionment is attempted using data of aerosol collected by traditional cascade impactors. Seven factors were identified: wood burning, industry, resuspended dust, regional aerosol, construction works, traffic 1, and traffic 2. Further insights into size-segregated factor profiles suggested that the traffic 1 factor can be associated to diesel vehicles and traffic 2 to gasoline vehicles. The regional aerosol factor resulted to be the main contributor (nearly 50%) to the droplet mode (accumulation sub-mode with modal diameter in the range 0.5-1 μm), whereas the overall contribution from the two factors related to traffic was the most important one in the other size modes (34-41%). The results showed that applying a 3-D receptor model to size-segregated samples allows identifying factors of local and regional origin while receptor modelling on integrated PM fractions usually singles out factors characterised by primary (e.g. industry, traffic, soil dust) and secondary (e.g. ammonium sulphate and nitrate) origin. Furthermore, the results suggested that the information on size-segregated chemical composition in different size classes was exploited by the model to relate primary emissions to rapidly-formed secondary compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Toward Synchronous Evaluation of Source Apportionments for Atmospheric Concentration and Deposition of Sulfate Aerosol Over East Asia

NASA Astrophysics Data System (ADS)

Itahashi, S.

2018-03-01

Source apportionments for atmospheric concentration, dry deposition, and wet deposition of sulfate aerosol (SO42-) were synchronously evaluated over East Asia, a main source of anthropogenic sulfur dioxide (SO2) emissions. Estimating dry deposition was difficult owing to the difficulty of measuring deposition velocity directly; therefore, sensitivity simulations using two dry deposition schemes were conducted. Moreover, sensitivity simulations for different emission inventories, the largest uncertainty source in the air quality model, were also conducted. In total, four experimental settings were used. Model performance was verified for atmospheric concentration and wet deposition using a ground-based observation network in China, Korea, and Japan, and all four model settings captured the observations. The underestimation of wet deposition over China was improved by an adjusted approach that linearly scaled the modeled precipitation values to observations. The synchronous evaluation of source apportionments for atmospheric concentration and dry and wet deposition showed the dominant contribution of anthropogenic emissions from China to the atmospheric concentration and deposition in Japan. The contributions of emissions from volcanoes were more important for wet deposition than for atmospheric concentration. Differences in the dry deposition scheme and emission inventory did not substantially influence the relative ratio of source apportionments over Japan. Because the dry deposition was more attributed to local factors, the differences in dry deposition may be an important determinant of the source contributions from China to Japan. Verification of these findings, including the dry deposition velocity, is necessary for better understanding of the behavior of sulfur compound in East Asia.

SOURCE APPORTIONMENT OF PRIMARY AND SECONDARY CARBONACEOUS AEROSOL IN THE UNITED STATES USING MODELS AND MEASUREMENTS

EPA Science Inventory

In this presentation, three diagnostic evaluation methods of model performance for carbonaceous aerosol are reviewed. The EC-tracer method is used to distinguish primary and secondary carbon, radiocarbon data are used to distinguish fossil-fuel and contemporary carbon, and organ...

Quantifying impacts on air quality of vehicular emissions in Sao Paulo and Rio de Janeiro

NASA Astrophysics Data System (ADS)

Artaxo, Paulo; Ferreira de Brito, Joel; Godoy, José Marcus; Luiza Godoy, Maria; Junior, Djacinto

2016-04-01

Vehicular emissions in megacities such as Sao Paulo and Rio de Janeiro are increasingly becoming a global issue. The São Paulo Metropolitan Area (SPMA), located in Southeast of Brazil, is a megacity with a population of 18 million people, with 7 million cars and large-scale industrial emissions. Rio de Janeiro is also a large city with different meteorology than São Paulo. All cars in Brazil runs gasohol, with 23% ethanol in gasoline, and for the last 10 years, flex cars that can run on gasohol, ethanol or any mixture dominate the market. Overall ethanol accounts for about 30-40% of fuel burned in both cities. To improve the understanding of vehicular emission impacts on aerosol composition and life cycle in these two large megacities a source apportionment study, combining online and offline measurements, was performed. Aerosols were collected for one year to capture seasonal variability at 4 sites in each city, with inorganic and organic aerosol component being sampled. Organic and elemental carbon were measured using a Sunset Laboratory Dual Optics (transmission and reflectance) Carbon Analyzer and about 22 trace elements has been measured using polarized X-Ray Fluorescence (XRF). Aerosol mass and black carbon were also measured, as well as trace gases to help in aerosol source apportionment. In Sao Paulo, the average PM2.5 mass concentration obtained varied from 9.6 to 12.2 μg m-3 for the several sites, and similar concentrations were measured in Rio de Janeiro. At all sites, organic matter (OM) has dominated fine mode aerosol concentration with 42 to 60% of the aerosol mass. EC accounted for 21 to 31% of fine mode aerosol mass concentration. Sulfate accounted for 21 to 26% of PM2.5 for the sites. Aerosol source apportionment was done with receptor analysis and integration with online data such as PTR-MS, Aethalometers, Nephelometers and ACSM helped to apportion vehicular emissions. For the 8 sites operated in Sao Paulo and Rio de Janeiro, vehicular emissions accounts for about 63% of PM2.5. Results are very similar for the different sites and cities.

Isotope source apportionment of carbonaceous aerosol as a function of particle size and thermal refractiveness

NASA Astrophysics Data System (ADS)

Masalaite, Agne; Holzinger, Rupert; Remeikis, Vidmantas; Röckmann, Thomas; Dusek, Ulrike

2016-04-01

The stable carbon isotopes can be used to get information about sources and processing of carbonaceous aerosol. We will present results from source apportionment of carbonaceous aerosol as a function of particle size thermal refractiveness. Separate source apportionment for particles smaller than 200 nm and for different carbon volatility classes are rarely reported and give new insights into aerosol sources in the urban environment. Stable carbon isotope ratios were measured for the organic carbon (OC) fraction and total carbon (TC) of MOUDI impactor samples that were collected on a coastal site (Lithuania) during the winter 2012 and in the city of Vilnius (Lithuania) during the winter of 2009. The 11 impactor stages spanned a size range from 0.056 to 18 μm, but only the 6 stages in the submicron range were analysed. The δ13C values of bulk total carbon (δ13CTC) were determined with an elemental analyser (Flash EA 1112) coupled with an isotope ratio mass spectrometer (Thermo Finnigan Delta Plus Advantage) (EA - IRMS). Meanwhile δ13COC was measured using thermal-desorption isotope ratio mass spectrometry (IRMS) system. This allows a rough separation of the more volatile OC fraction (desorbed in the oven of IRMS up to 250 0C) from the more refractory fraction (desorbed up to 400 0C). In this study we investigated the composition of organic aerosol desorbed from filter samples at different temperatures using the thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) technique. During winter-time in Lithuania we expect photochemistry and biogenic emissions to be of minor importance. The main sources of aerosol carbon should be fossil fuel and biomass combustion. In both sites, the coastal and the urban site, δ13C measurements give a clear indication that the source contributions differ for small and large particles. Small particles < 200 nm are depleted in 13C with respect to larger particles by 1 - 2 ‰Ṫhis shows that OC in small particle arises mainly from fossil fuel sources, whereas OC in larger particles from 200 nm to 1 μm has higher contribution from biomass burning/other sources. Moreover, there is a clear distinction in source contribution between the more volatile OC fraction and the more refractory fraction. The more refractory fraction is enriched in 13C by 1 to 2 ‰ for both small and large particles. These results show that the fossil fuel combustion is associated to a larger degree with more volatile carbon, whereas biomass burning is the main source of the more refractory particles. According to our source apportionment, the more volatile carbon fraction in the smallest particles is almost completely from fossil fuels, whereas the more refractory carbon fraction in the large size range is almost complete from biomass burning. The more refractory small particles and the less refractory large particles are roughly an even mix of these two sources. The detailed chemical speciation of the carbonaceous aerosol will be presented as well. Acknowledgements This study was funded by the Dutch Science Foundation (NWO grants Nr. 820.01.001, and 834.08.002).

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

2004-12-01

This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2004 through August 2004. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. Results highlighted in this report include evaluation of the performance of PMCAMx+ for an air pollution episode in the Eastern US, an emission profile for a coke production facility, ultrafine particle composition during a nucleation event, and a new hybrid approach for source apportionment. An agreement was reached with a utility to characterize fine particle and mercury emissionsmore » from a commercial coal fired power. Research in the next project period will include source testing of a coal fired power plant, source apportionment analysis, emission scenario modeling with PMCAMx+, and writing up results for submission as journal articles.« less

Large contribution of fossil fuel derived secondary organic carbon to water soluble organic aerosols in winter haze in China

NASA Astrophysics Data System (ADS)

Zhang, Yan-Lin; El-Haddad, Imad; Huang, Ru-Jin; Ho, Kin-Fai; Cao, Jun-Ji; Han, Yongming; Zotter, Peter; Bozzetti, Carlo; Daellenbach, Kaspar R.; Slowik, Jay G.; Salazar, Gary; Prévôt, André S. H.; Szidat, Sönke

2018-03-01

Water-soluble organic carbon (WSOC) is a large fraction of organic aerosols (OA) globally and has significant impacts on climate and human health. The sources of WSOC remain very uncertain in polluted regions. Here we present a quantitative source apportionment of WSOC, isolated from aerosols in China using radiocarbon (14C) and offline high-resolution time-of-flight aerosol mass spectrometer measurements. Fossil emissions on average accounted for 32-47 % of WSOC. Secondary organic carbon (SOC) dominated both the non-fossil and fossil derived WSOC, highlighting the importance of secondary formation to WSOC in severe winter haze episodes. Contributions from fossil emissions to SOC were 61 ± 4 and 50 ± 9 % in Shanghai and Beijing, respectively, significantly larger than those in Guangzhou (36 ± 9 %) and Xi'an (26 ± 9 %). The most important primary sources were biomass burning emissions, contributing 17-26 % of WSOC. The remaining primary sources such as coal combustion, cooking and traffic were generally very small but not negligible contributors, as coal combustion contribution could exceed 10 %. Taken together with earlier 14C source apportionment studies in urban, rural, semi-urban and background regions in Asia, Europe and the USA, we demonstrated a dominant contribution of non-fossil emissions (i.e., 75 ± 11 %) to WSOC aerosols in the Northern Hemisphere; however, the fossil fraction is substantially larger in aerosols from East Asia and the eastern Asian pollution outflow, especially during winter, due to increasing coal combustion. Inclusion of our findings can improve a modelling of effects of WSOC aerosols on climate, atmospheric chemistry and public health.

Source apportionments of aerosols and their direct radiative forcing and long-term trends over continental United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yang; Wang, Hailong; Smith, Steven J.

Due to US air pollution regulations, aerosol and precursor emissions have decreased during recent decades, while changes in emissions in other regions of the world also influence US aerosol trends through long-range transport. We examine here the relative roles of these domestic and foreign emission changes on aerosol concentrations and direct radiative forcing (DRF) at the top of the atmosphere over the continental US. Long-term (1980-2014) trends and aerosol source apportionment are quantified in this study using a global aerosol-climate model equipped with an explicit aerosol source tagging technique. Due to US emission control policies, the annual mean near-surface concentrationmore » of particles, consisting of sulfate, black carbon, and primary organic aerosol, decreases by about –1.1 (±0.1) / –1.4 (±0.1) μg m -3 in western US and –3.3 (±0.2) / –2.9 (±0.2) μg m -3 in eastern US during 2010–2014, as compared to those in 1980–1984. Meanwhile, decreases in US emissions lead to a warming of +0.48 (±0.03) / –0.46 (±0.03) W m -2 in western US and +1.41 (±0.07) /+1.32 (±0.09) W m -2 in eastern US through changes in aerosol DRF. Increases in emissions from East Asia generally have a modest impact on US air quality, but mitigated the warming effect induced by reductions in US emissions by 25% in western US and 7% in eastern US. Thus, as US domestic aerosol and precursor emissions continue to decrease, foreign emissions may become increasingly important to radiative forcing over the US.« less

Source apportionments of aerosols and their direct radiative forcing and long-term trends over continental United States

DOE PAGES

Yang, Yang; Wang, Hailong; Smith, Steven J.; ...

2018-05-23

Due to US air pollution regulations, aerosol and precursor emissions have decreased during recent decades, while changes in emissions in other regions of the world also influence US aerosol trends through long-range transport. We examine here the relative roles of these domestic and foreign emission changes on aerosol concentrations and direct radiative forcing (DRF) at the top of the atmosphere over the continental US. Long-term (1980-2014) trends and aerosol source apportionment are quantified in this study using a global aerosol-climate model equipped with an explicit aerosol source tagging technique. Due to US emission control policies, the annual mean near-surface concentrationmore » of particles, consisting of sulfate, black carbon, and primary organic aerosol, decreases by about –1.1 (±0.1) / –1.4 (±0.1) μg m -3 in western US and –3.3 (±0.2) / –2.9 (±0.2) μg m -3 in eastern US during 2010–2014, as compared to those in 1980–1984. Meanwhile, decreases in US emissions lead to a warming of +0.48 (±0.03) / –0.46 (±0.03) W m -2 in western US and +1.41 (±0.07) /+1.32 (±0.09) W m -2 in eastern US through changes in aerosol DRF. Increases in emissions from East Asia generally have a modest impact on US air quality, but mitigated the warming effect induced by reductions in US emissions by 25% in western US and 7% in eastern US. Thus, as US domestic aerosol and precursor emissions continue to decrease, foreign emissions may become increasingly important to radiative forcing over the US.« less

Spatial and temporal variations of aerosols around Beijing in summer 2006: Model evaluation and source apportionment

NASA Astrophysics Data System (ADS)

Matsui, H.; Koike, M.; Kondo, Y.; Takegawa, N.; Kita, K.; Miyazaki, Y.; Hu, M.; Chang, S.; Blake, D. R.; Fast, J. D.; Zaveri, R. A.; Streets, D. G.; Zhang, Q.; Zhu, T.

2009-12-01

Regional aerosol model calculations were made using the WRF-CMAQ and WRF-chem models to study spatial and temporal variations of aerosols around Beijing, China, in the summer of 2006, when the CAREBEIJING-2006 intensive campaign was conducted. Model calculations captured temporal variations of primary (such as elemental carbon, EC) and secondary (such as sulfate) aerosols observed in and around Beijing. The spatial distributions of aerosol optical depth observed by the MODIS satellite sensors were also reproduced over northeast China. Model calculations showed distinct differences in spatial distributions between primary and secondary aerosols in association with synoptic-scale meteorology. Secondary aerosols increased in air around Beijing on a scale of about 1000 x 1000 km2 under an anticyclonic pressure system. This airmass was transported northward from the high anthropogenic emission area extending south of Beijing with continuous photochemical production. Subsequent cold front passage brought clean air from the north, and polluted air around Beijing was swept to the south of Beijing. This cycle was repeated about once a week and was found to be responsible for observed enhancements/reductions of aerosols at the intensive measurement sites. In contrast to secondary aerosols, the spatial distributions of primary aerosols (EC) reflected those of emissions, resulting in only slight variability despite the changes in synoptic-scale meteorology. In accordance with these results, source apportionment simulations revealed that primary aerosols around Beijing were controlled by emissions within 100 km around Beijing within the preceding 24 hours, while emissions as far as 500 km and within the preceding 3 days were found to affect secondary aerosols.

Two years of near real-time observations of the chemical composition of submicron aerosols in Cape Corsica obtained by Q-ACSM

NASA Astrophysics Data System (ADS)

Sciare, Jean; Dulac, François; Crenn, Vincent; Hamonou, Eric; Baisnée, Dominique; Nicolas, José B.; Pont, Véronique; Lambert, Dominique; Gheusi, François; Mallet, Marc; Tison, Emmanuel; Sauvage, Stéphane; Bourrianne, Thierry; Roberts, Gregory; Colomb, Aurélie; Pichon, Jean-Marc; Sellegri, Karine; Savelli, Jean-Luc

2015-04-01

As part of the MISTRALS/ChArMEx (Mediterranean Integrated Studies aT Regional And Local Scales/the Chemistry-Aerosol Mediterranean Experiment; http://www.mistrals-home.org; http://charmex.lsce.ipsl.fr) and the CORSiCA (http://www.obs-mip.fr/corsica) programs, 2-year continuous observations of near real-time chemical composition of submicron aerosols were performed between June 2012 & July 2014 at the Cape Corsica atmospheric supersite (http://gaw.empa.ch/gawsis/reports.asp?StationID=2076203042), a remote marine site in the Western Mediterranean. Submicron organic aerosols (OA) and the major inorganic salts (sulfate, ammonium, nitrate) were monitored every 30 min using a Quadripole Aerosol Chemical Speciation Monitor (Q-ACSM; Aerodyne Res. Inc. MA, USA). Quality control of this large dataset (24-month continuous observations) was performed through closure studies (using co-located SMPS and TEOM-FDMS measurements), direct comparisons with other on-line / off-line instruments running in parallel (filter sampling, OPC, nephelometer …), and large intercomparison of 13 Q-ACSM performed within the EU-FP7 ACTRIS program (http://www.actris.net/). Source apportionment of OA was then performed on a monthly basis using the SourceFinder software (SoFi, http://www.psi.ch/acsm-stations/me-2) allowing the distinction between hydrogen- and oxygen-like organic aerosols (HOA and OOA, respectively). This monthly resolved source apportionment was first compared with co-located real-time tracer measurements (NOx, BC, CO, VOC …) available at the Cape Corsica station. Seasonal patterns of the various properties of (secondary) OOA (OSc, O/C ratio …) were then investigated from monthly resolved source apportionment results (monthly OOA mass spectra) obtained over the period June 2012 - July 2014. Acknowledgements: Atmospheric measurements performed at Cape Corsica Station were funded by CNRS-INSU, ADEME, CEA, and METEO-FRANCE. This work was carried out in the framework of the CORSiCA project funded by the Collectivité Territoriale de Corse through the Fonds Européen de Développement Régional of the European Operational Program 2007-2013 and the Contrat de Plan Etat Région.

Identifying the Sources Contributing to PM Exceedances in Ostrava, Czech Republic, Using Passive Aerosol Sampling Coupled with Computer-Controlled Microscopy

EPA Science Inventory

The Czech Hydrometeorological Institute (CHMI) in collaboration with the U.S. Environmental Protection Agency conducted a multi-pollutant source apportionment study in 2012 to quantify the impact of regional as well as local sources on air quality in the Ostrava metropolitan area...

Water soluble organic aerosols in the Colorado Rocky Mountains, USA: composition, sources and optical properties

PubMed Central

Xie, Mingjie; Mladenov, Natalie; Williams, Mark W.; Neff, Jason C.; Wasswa, Joseph; Hannigan, Michael P.

2016-01-01

Atmospheric aerosols have been shown to be an important input of organic carbon and nutrients to alpine watersheds and influence biogeochemical processes in these remote settings. For many remote, high elevation watersheds, direct evidence of the sources of water soluble organic aerosols and their chemical and optical characteristics is lacking. Here, we show that the concentration of water soluble organic carbon (WSOC) in the total suspended particulate (TSP) load at a high elevation site in the Colorado Rocky Mountains was strongly correlated with UV absorbance at 254 nm (Abs254, r = 0.88 p < 0.01) and organic carbon (OC, r = 0.95 p < 0.01), accounting for >90% of OC on average. According to source apportionment analysis, biomass burning had the highest contribution (50.3%) to average WSOC concentration; SOA formation and motor vehicle emissions dominated the contribution to WSOC in the summer. The source apportionment and backward trajectory analysis results supported the notion that both wildfire and Colorado Front Range pollution sources contribute to the summertime OC peaks observed in wet deposition at high elevation sites in the Colorado Rocky Mountains. These findings have important implications for water quality in remote, high-elevation, mountain catchments considered to be our pristine reference sites. PMID:27991554

Source Contributions to Wintertime Elemental and Organic Carbon in the Western Arctic Based on Radiocarbon and Tracer Apportionment.

PubMed

Barrett, T E; Robinson, E M; Usenko, S; Sheesley, R J

2015-10-06

To quantify the contributions of fossil and biomass sources to the wintertime Arctic aerosol burden source apportionment is reported for elemental (EC) and organic carbon (OC) fractions of six PM10 samples collected during a wintertime (2012-2013) campaign in Barrow, AK. Radiocarbon apportionment of EC indicates that fossil sources contribute an average of 68 ± 9% (0.01-0.07 μg m(-3)) in midwinter decreasing to 49 ± 6% (0.02 μg m(-3)) in late winter. The mean contribution of fossil sources to OC for the campaign was stable at 38 ± 8% (0.04-0.32 μg m(-3)). Samples were also analyzed for organic tracers, including levoglucosan, for use in a chemical mass balance (CMB) source apportionment model. The CMB model was able to apportion 24-53% and 99% of the OC and EC burdens, respectively, during the campaign, with fossil OC contributions ranging from 25 to 74% (0.02-0.09 μg m(-3)) and fossil EC contributions ranging from 73 to 94% (0.03-0.07 μg m(-3)). Back trajectories identified two major wintertime source regions to Barrow: the Russian and North American Arctic. Atmospheric lifetimes of levoglucosan, ranging from 50 to 320 h, revealed variability in wintertime atmospheric processing of this biomass burning tracer. This study allows for unambiguous apportionment of EC to fossil fuel and biomass combustion sources and intercomparison with CMB modeling.

Source Apportionment of the Summer Time Carbonaceous Aerosol at Nordic Rural Background Sites

EPA Science Inventory

In the present study, natural and anthropogenic sources of particulate organic carbon (OC_p) and elemental carbon (EC) have been quantified based on weekly filter samples of PM₁₀ (particles with aerodynamic diameter <10µ collected at four Nordic rural backgro...

Source Apportionment of Primary and Secondary Organic Aerosol Using Positive Matrix Factorization (PMF) of Molecular Markers

EPA Science Inventory

Monthly average ambient concentrations of more than eighty particle-phase organic compounds, as well as total organic carbon (OC) and elemental carbon (EC), were measured from March 2004 through February 2005 in five cities in the Midwestern United States. A multi-variant source...

Spatial and temporal variations of aerosols around Beijing in summer 2006: Model evaluation and source apportionment

NASA Astrophysics Data System (ADS)

Matsui, H.; Koike, M.; Kondo, Y.; Takegawa, N.; Kita, K.; Miyazaki, Y.; Hu, M.; Chang, S.-Y.; Blake, D. R.; Fast, J. D.; Zaveri, R. A.; Streets, D. G.; Zhang, Q.; Zhu, T.

2009-01-01

Regional aerosol model calculations were made using the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) and WRF-chem models to study spatial and temporal variations of aerosols around Beijing, China, in the summer of 2006, when the Campaigns of Air Quality Research in Beijing and Surrounding Region 2006 (CAREBeijing) intensive campaign was conducted. Model calculations captured temporal variations of primary (such as elemental carbon (EC)) and secondary (such as sulfate) aerosols observed in and around Beijing. The spatial distributions of aerosol optical depth observed by the MODIS satellite sensors were also reproduced over northeast China. Model calculations showed distinct differences in spatial distributions between primary and secondary aerosols in association with synoptic-scale meteorology. Secondary aerosols increased in air around Beijing on a scale of about 1000 × 1000 km2 under an anticyclonic pressure system. This air mass was transported northward from the high anthropogenic emission area extending south of Beijing with continuous photochemical production. Subsequent cold front passage brought clean air from the north, and polluted air around Beijing was swept to the south of Beijing. This cycle was repeated about once a week and was found to be responsible for observed enhancements/reductions of aerosols at the intensive measurement sites. In contrast to secondary aerosols, the spatial distributions of primary aerosols (EC) reflected those of emissions, resulting in only slight variability despite the changes in synoptic-scale meteorology. In accordance with these results, source apportionment simulations revealed that primary aerosols around Beijing were controlled by emissions within 100 km around Beijing within the preceding 24 h, while emissions as far as 500 km and within the preceding 3 days were found to affect secondary aerosols.

Atmospheric aerosol composition and source apportionments to aerosol in southern Taiwan

NASA Astrophysics Data System (ADS)

Tsai, Ying I.; Chen, Chien-Lung

In this study, the chemical characteristics of winter aerosol at four sites in southern Taiwan were determined and the Gaussian Trajectory transfer coefficient model (GTx) was then used to identify the major air pollutant sources affecting the study sites. Aerosols were found to be acidic at all four sites. The most important constituents of the particulate matter (PM) by mass were SO 42-, organic carbon (OC), NO 3-, elemental carbon (EC) and NH 4+, with SO 42-, NO 3-, and NH 4+ together constituting 86.0-87.9% of the total PM 2.5 soluble inorganic salts and 68.9-78.3% of the total PM 2.5-10 soluble inorganic salts, showing that secondary photochemical solution components such as these were the major contributors to the aerosol water-soluble ions. The coastal site, Linyuan (LY), had the highest PM mass percentage of sea salts, higher in the coarse fraction, and higher sea salts during daytime than during nighttime, indicating that the prevailing daytime sea breeze brought with it more sea-salt aerosol. Other than sea salts, crustal matter, and EC in PM 2.5 at Jenwu (JW) and in PM 2.5-10 at LY, all aerosol components were higher during nighttime, due to relatively low nighttime mixing heights limiting vertical and horizontal dispersion. At JW, a site with heavy traffic loadings, the OC/EC ratio in the nighttime fine and coarse fractions of approximately 2.2 was higher than during daytime, indicating that in addition to primary organic aerosol (POA), secondary organic aerosol (SOA) also contributed to the nighttime PM 2.5. This was also true of the nighttime coarse fraction at LY. The GTx produced correlation coefficients ( r) for simulated and observed daily concentrations of PM 10 at the four sites (receptors) in the range 0.45-0.59 and biases from -6% to -20%. Source apportionment indicated that point sources were the largest PM 10 source at JW, LY and Daliao (DL), while at Meinung (MN), a suburban site with less local PM 10, SO x and NO x emissions, upwind boundary concentration was the major PM 10 source, followed by point sources and top boundary concentration.

The ambient aerosol characterization during the prescribed bushfire season in Brisbane 2013.

PubMed

Milic, A; Miljevic, B; Alroe, J; Mallet, M; Canonaco, F; Prevot, A S H; Ristovski, Z D

2016-08-01

Prescribed burnings are conducted in Queensland each year from August until November aiming to decrease the impact of bushfire hazards and maintain the health of vegetation. This study reports chemical characteristics of the ambient aerosol, with a focus on source apportionment of the organic aerosol (OA) fraction, during the prescribed biomass burning (BB) season in Brisbane 2013. All measurements were conducted within the International Laboratory for Air Quality and Health (ILAQH) located in Brisbane's Central Business District. Chemical composition, degree of ageing and the influence of BB emission on the air quality of central Brisbane were characterized using a compact Time of Flight Aerosol Mass Spectrometer (cToF-AMS). AMS loadings were dominated by OA (64%), followed by, sulfate (17%), ammonium (14%) and nitrates (5%). Source apportionment was applied on the AMS OA mass spectra via the multilinear engine solver (ME-2) implementation within the recently developed Source Finder (SoFi) interface. Six factors were extracted including hydrocarbon-like OA (HOA), cooking-related OA (COA), biomass burning OA (BBOA), low-volatility oxygenated OA (LV-OOA), semivolatile oxygenated OA (SV-OOA), and nitrogen-enriched OA (NOA). The aerosol fraction that was attributed to BB factor was 9%, on average over the sampling period. The high proportion of oxygenated OA (72%), typically representing aged emissions, could possess a fraction of oxygenated species transfored from BB components on their way to the sampling site. Copyright © 2016 Elsevier B.V. All rights reserved.

Source Apportionment of PM2.5 in Delhi, India Using PMF Model.

PubMed

Sharma, S K; Mandal, T K; Jain, Srishti; Saraswati; Sharma, A; Saxena, Mohit

2016-08-01

Chemical characterization of PM2.5 [organic carbon, elemental carbon, water soluble inorganic ionic components, and major and trace elements] was carried out for a source apportionment study of PM2.5 at an urban site of Delhi, India from January, 2013, to December, 2014. The annual average mass concentration of PM2.5 was 122 ± 94.1 µg m(-3). Strong seasonal variation was observed in PM2.5 mass concentration and its chemical composition with maxima during winter and minima during monsoon. A receptor model, positive matrix factorization (PMF) was applied for source apportionment of PM2.5 mass concentration. The PMF model resolved the major sources of PM2.5 as secondary aerosols (21.3 %), followed by soil dust (20.5 %), vehicle emissions (19.7 %), biomass burning (14.3 %), fossil fuel combustion (13.7 %), industrial emissions (6.2 %) and sea salt (4.3 %).

Apportionment of urban aerosol sources in Chongqing (China) using synergistic on-line techniques

NASA Astrophysics Data System (ADS)

Chen, Yang; Yang, Fumo

2016-04-01

The sources of ambient fine particulate matter (PM2.5) during wintertime at a background urban location in Chongqing (southwestern China) have been determined. Aerosol chemical composition analyses were performed using multiple on-line techniques, such as single particle aerosol mass spectrometer (SPAMS) for single particle chemical composition, on-line elemental carbon-organic carbon analyzer (on-line OC-EC), on-line X-ray fluorescence (XRF) for elements, and in-situ Gas and Aerosol Compositions monitor (IGAC) for water-soluble ions in PM2.5. All the datasets from these techniques have been adjusted to a 1-h time resolution for receptor model input. Positive matrix factorization (PMF) has been used for resolving aerosol sources. At least six sources, including domestic coal burning, biomass burning, dust, traffic, industrial and secondary/aged factors have been resolved and interpreted. The synergistic on-line techniques were helpful for identifying aerosol sources more clearly than when only employing the results from the individual techniques. This results are useful for better understanding of aerosol sources and atmospheric processes.

Characterizing and sourcing ambient PM2.5 over key emission regions in China III: Carbon isotope based source apportionment of black carbon

NASA Astrophysics Data System (ADS)

Yu, Kuangyou; Xing, Zhenyu; Huang, Xiaofeng; Deng, Junjun; Andersson, August; Fang, Wenzheng; Gustafsson, Örjan; Zhou, Jiabin; Du, Ke

2018-03-01

Regional haze over China has severe implications for air quality and regional climate. To effectively combat these effects the high uncertainties regarding the emissions from different sources needs to be reduced. In this paper, which is the third in a series on the sources of PM2.5 in pollution hotspot regions of China, we focus on the sources of black carbon aerosols (BC), using carbon isotope signatures. Four-season samples were collected at two key locations: Beijing-Tianjin-Hebei (BTH, part of Northern China plain), and the Pearl River Delta (PRD). We find that that fossil fuel combustion was the predominant source of BC in both BTH and PRD regions, accounting for 75 ± 5%. However, the contributions of what fossil fuel components were dominating differed significantly between BTH and PRD, and varied dramatically with seasons. Coal combustion is overall the all-important BC source in BTH, accounting for 46 ± 12% of the BC in BTH, with the maximum value (62%) found in winter. In contrast for the PRD region, liquid fossil fuel combustion (e.g., oil, diesel, and gasoline) is the dominant source of BC, with an annual mean value of 41 ± 15% and the maximum value of 55% found in winter. Region- and season-specific source apportionments are recommended to both accurately assess the climate impact of carbonaceous aerosol emissions and to effectively mitigate deteriorating air quality caused by carbonaceous aerosols.

Improved source apportionment of organic aerosols in complex urban air pollution using the multilinear engine (ME-2)

NASA Astrophysics Data System (ADS)

Zhu, Qiao; Huang, Xiao-Feng; Cao, Li-Ming; Wei, Lin-Tong; Zhang, Bin; He, Ling-Yan; Elser, Miriam; Canonaco, Francesco; Slowik, Jay G.; Bozzetti, Carlo; El-Haddad, Imad; Prévôt, André S. H.

2018-02-01

Organic aerosols (OAs), which consist of thousands of complex compounds emitted from various sources, constitute one of the major components of fine particulate matter. The traditional positive matrix factorization (PMF) method often apportions aerosol mass spectrometer (AMS) organic datasets into less meaningful or mixed factors, especially in complex urban cases. In this study, an improved source apportionment method using a bilinear model of the multilinear engine (ME-2) was applied to OAs collected during the heavily polluted season from two Chinese megacities located in the north and south with an Aerodyne high-resolution aerosol mass spectrometer (HR-ToF-AMS). We applied a rather novel procedure for utilization of prior information and selecting optimal solutions, which does not necessarily depend on other studies. Ultimately, six reasonable factors were clearly resolved and quantified for both sites by constraining one or more factors: hydrocarbon-like OA (HOA), cooking-related OA (COA), biomass burning OA (BBOA), coal combustion (CCOA), less-oxidized oxygenated OA (LO-OOA) and more-oxidized oxygenated OA (MO-OOA). In comparison, the traditional PMF method could not effectively resolve the appropriate factors, e.g., BBOA and CCOA, in the solutions. Moreover, coal combustion and traffic emissions were determined to be primarily responsible for the concentrations of PAHs and BC, respectively, through the regression analyses of the ME-2 results.

Radiocarbon-based Source Apportionment of Organic, Elemental and Water-soluble Organic Carbon Aerosols and the Light Absorption of Water-soluble Organic Carbon Aerosols in the East Asia High-intensity Winter Campaigns in 2014

NASA Astrophysics Data System (ADS)

Fang, W.; Andersson, A.; Zheng, M.; Lee, M.; Kim, S. W.; Du, K.; Gustafsson, O.

2016-12-01

Improved understanding of anthropogenic aerosol effects on atmospheric chemistry and climate as well as efficient mitigation actions are hampered by the limited comprehension of the relative contributions of different sources of carbonaceous aerosols and of their subsequent atmospheric processing. Here, we present dual carbon isotope constrained source apportionment and optical properties of carbonaceous aerosols simultaneously both at urban and rural receptor sites, includes North China Plain (NCP, Beijing and Tianjin), Yangtze River Delta (YRD, Shanghai, Zhejiang), and Jeju Island (Korea Climate Observatory at Gosan) during January 2014 field campaigns. The radiocarbon (Δ14C) data show that fossil combustions contribute equally ˜80 ± 5% to elemental carbon (EC) aerosol in Beijing, Tianjin, and Shanghai, and 66 ± 9% to Gosan-EC aerosol, while the specific sources of the dominant fossil fuel component were dramatically different among these sites. The mean fraction coal combustion of Beijing-EC, Tianjin-EC, and Gosan-EC is double that of Shanghai-EC. The other large fraction (72―92%) of carbonaceous aerosol is organic carbon (OC) aerosol which contains water soluble and water insoluble organic carbon (WSOC and WISOC). OC, WISOC, and WSOC in Beijing and Gosan sites were still observed largely from fossil sources (53―75%). The more 13C-enriched signature of Gosan-WSOC (-22.8 ± 0.2‰) compared to Gosan-EC (-23.9 ± 0.4‰) and Beijing-WSOC (-23.5 ± 0.7‰) reflects that WSOC is likely more affected by atmospheric aging during long-rang transport than is EC. The high light absorption coefficients of PM2.5, PM1, and TSP were observed at Gosan during this study and was frequently reaching 20―60 Mm-1 by aethalometer and continuous light absorption photometer. The mass absorption cross section of WSOC (MAC365) for above sites is high (1.5 ± 0.8 m2/g), accounted for ˜14 ± 5% of the total direct absorbance relative to EC, which is significantly higher than the previous findings in S. Asia, N. America, and Europe.

Characteristics and Source Apportionment of Marine Aerosols over East China Sea Using a Source-oriented Chemical Transport Model

NASA Astrophysics Data System (ADS)

Kang, M.; Zhang, H.; Fu, P.

2017-12-01

Marine aerosols exert a strong influence on global climate change and biogeochemical cycling, as oceans cover beyond 70% of the Earth's surface. However, investigations on marine aerosols are relatively limited at present due to the difficulty and inconvenience in sampling marine aerosols as well as their diverse sources. East China Sea (ECS), lying over the broad shelf of the western North Pacific, is adjacent to the Asian mainland, where continental-scale air pollution could impose a heavy load on the marine atmosphere through long-range atmospheric transport. Thus, contributions of major sources to marine aerosols need to be identified for policy makers to develop cost effective control strategies. In this work, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model, which can directly track the contributions from multiple emission sources to marine aerosols, is used to investigate the contributions from power, industry, transportation, residential, biogenic and biomass burning to marine aerosols over the ECS in May and June 2014. The model simulations indicate significant spatial and temporal variations of concentrations as well as the source contributions. This study demonstrates that the Asian continent can greatly affect the marine atmosphere through long-range transport.

Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

NASA Astrophysics Data System (ADS)

Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

2012-07-01

Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

Characteristics and source apportionment of PM2.5 during persistent extreme haze events in Chengdu, southwest China

NASA Astrophysics Data System (ADS)

Li, L.; Liu, S.

2017-12-01

Based on detailed data from Chengdu Plain (CP) from 6 January to 16 January 2015 , two typical haze episodes were analyzed to clarify the haze formation mechanism in winter. Weather conditions, chemical compositions, secondary pollutant transformation, optical properties of aerosols, the potential source contribution function (PSCF) and source apportionment were studied. The planetary boundary layer (PBL) height decreased distinctly during the haze episodes and restrained air pollutant vertical dispersion. As the haze worsened, the value of PBL × PM2.5 increased notably. The [NO3-]/[SO42-] ratio was 0.61, 0.76 and 0.88 during a non-haze period, episode 1 and episode 2, respectively, indicating that the mobile source of the air pollution is increasingly predominant in Chengdu. Water vapor also played a vital role in the formation of haze by accelerating the chemical transformation of secondary pollutants, leading to the hygroscopic growth of aerosols. The PSCF and backward trajectories of the air masses indicated that the pollution mainly came from the south. The secondary inorganic aerosols, vehicle emissions, coal combustion, biomass burning, industry, and dust contributed 34.1%, 24.1%, 12.7%, 12.3%, 7.6%, and 7.2% to PM2.5 masses in episode 1 and 28.9%, 23.1%, 9.4%, 9.5%, 20.3% and 7.5% in episode 2.

Characteristics and source apportionment of PM2.5 during persistent extreme haze events in Chengdu, southwest China.

PubMed

Li, Lulu; Tan, Qinwen; Zhang, Yuanhang; Feng, Miao; Qu, Yu; An, Junling; Liu, Xingang

2017-11-01

Based on detailed data from Chengdu Plain (CP) from 6 January to 16 January, two typical haze episodes were analyzed to clarify the haze formation mechanism in winter. Weather conditions, chemical compositions, secondary pollutant transformation, optical properties of aerosols, the potential source contribution function (PSCF) and source apportionment were studied. The planetary boundary layer (PBL) height decreased distinctly during the haze episodes and restrained air pollutant vertical dispersion. As the haze worsened, the value of PBL × PM 2.5 increased notably. The [NO 3 - ]/[SO 4 2- ] ratio was 0.61, 0.76 and 0.88 during a non-haze period, episode 1 and episode 2, respectively, indicating that the mobile source of the air pollution is increasingly predominant in Chengdu. Water vapor also played a vital role in the formation of haze by accelerating the chemical transformation of secondary pollutants, leading to the hygroscopic growth of aerosols. The PSCF and backward trajectories of the air masses indicated that the pollution mainly came from the south. The secondary inorganic aerosols, vehicle emissions, coal combustion, biomass burning, industry, and dust contributed 34.1%, 24.1%, 12.7%, 12.3%, 7.6%, and 7.2% to PM 2.5 masses in episode 1 and 28.9%, 23.1%, 9.4%, 9.5%, 20.3% and 7.5% in episode 2. Copyright © 2017 Elsevier Ltd. All rights reserved.

Organic aerosol source apportionment by offline-AMS over a full year in Marseille

NASA Astrophysics Data System (ADS)

Bozzetti, Carlo; El Haddad, Imad; Salameh, Dalia; Daellenbach, Kaspar Rudolf; Fermo, Paola; Gonzalez, Raquel; Cruz Minguillón, María; Iinuma, Yoshiteru; Poulain, Laurent; Elser, Miriam; Müller, Emanuel; Gates Slowik, Jay; Jaffrezo, Jean-Luc; Baltensperger, Urs; Marchand, Nicolas; Prévôt, André Stephan Henry

2017-07-01

We investigated the seasonal trends of OA sources affecting the air quality of Marseille (France), which is the largest harbor of the Mediterranean Sea. This was achieved by measurements of nebulized filter extracts using an aerosol mass spectrometer (offline-AMS). In total 216 PM2. 5 (particulate matter with an aerodynamic diameter < 2.5 µm) filter samples were collected over 1 year from August 2011 to July 2012. These filters were used to create 54 composite samples which were analyzed by offline-AMS. The same samples were also analyzed for major water-soluble ions, metals, elemental and organic carbon (EC / OC), and organic markers, including n-alkanes, hopanes, polycyclic aromatic hydrocarbons (PAHs), lignin and cellulose pyrolysis products, and nitrocatechols. The application of positive matrix factorization (PMF) to the water-soluble AMS spectra enabled the extraction of five factors, related to hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), oxygenated OA (OOA), and an industry-related OA (INDOA). Seasonal trends and relative contributions of OA sources were compared with the source apportionment of OA spectra collected from the AMS field deployment at the same station but in different years and for shorter monitoring periods (February 2011 and July 2008). Online- and offline-AMS source apportionment revealed comparable seasonal contribution of the different OA sources. Results revealed that BBOA was the dominant source during winter, representing on average 48 % of the OA, while during summer the main OA component was OOA (63 % of OA mass on average). HOA related to traffic emissions contributed on a yearly average 17 % to the OA mass, while COA was a minor source contributing 4 %. The contribution of INDOA was enhanced during winter (17 % during winter and 11 % during summer), consistent with an increased contribution from light alkanes, light PAHs (fluoranthene, pyrene, phenanthrene), and selenium, which is commonly considered as a unique coal combustion and coke production marker. Online- and offline-AMS source apportionments revealed evolving levoglucosan : BBOA ratios, which were higher during late autumn and March. A similar seasonality was observed in the ratios of cellulose combustion markers to lignin combustion markers, highlighting the contribution from cellulose-rich biomass combustion, possibly related to agricultural activities.

Source apportionment of carbonaceous aerosol in Sao Paulo using 13C and 14C measurements

NASA Astrophysics Data System (ADS)

Oyama, Beatriz; Andrade, Maria de Fatima; Holzinger, Rupert; Röckmann, Thomas; Meijer, Harro A. J.; Dusek, Ulrike

2016-04-01

The Metropolitan Area of Sao Paulo is affected by high aerosol concentrations, which contain a large fraction of organic material. Up to date, not much is known about the composition and origin of the organic aerosol in this city. We present the first source apportionment of the carbonaceous aerosol fraction in Sao Paulo, using stable (13C) and radioactive carbon isotopes (14C). 14C provides a clear-cut distinction between fossil sources, which contain no 14C, and contemporary sources such as biofuels, biomass burning, or biogenic sources, which contain a typical contemporary 14C/12C ratio. 13C can be used to distinguish C3 plants, such as maize and sugarcane, from C4 plants. This can help to identify a possible impact of sugarcane field burning in the rural areas of Sao Paulo State on the aerosol carbon in the city. In the first part of the study, we compare two tunnel studies: Tunnel 1 is frequented only by light duty vehicles, which run mainly on mixtures of gasoline with ethanol (gasohol, 25% ethanol and 85% gasoline) or hydrated ethanol (5% water and 95% ethanol). Tunnel 2 contains a significant fraction of heavy-duty diesel vehicles, and therefore the fraction of biofuels in the average fleet is lower. Comparison of 14C in organic and elemental carbon (OC and EC) shows that in both tunnels there is no significant contribution of biofuels to EC. Combusting ethanol-gasoline fuels in a vehicle engine does apparently not result in significant EC formation from ethanol. Biofuels contribute around 45% to OC in Tunnel 1 an only 20% in Tunnel 2, reflecting a strong impact of diesel vehicles in Tunnel 2. In the second part of the study we conduct a source apportionment of ambient aerosol carbon collected in a field study during winter (July-August) 2012. Ambient EC has two main sources, vehicular emissions and biomass burning. We estimate a contribution of vehicular sources to EC of roughly 90% during weekdays and 80% during weekends, using the 14C values measured in the tunnel studies. The absolute concentration of biomass burning EC is roughly 0.5 μg/m3 both during weekend and weekdays, whereas vehicular EC concentrations almost double during weekdays, increasing from 1.8 to 3.7 μg/m3 on average. OC concentrations are dominated by secondary carbon from vehicular emissions, both on weekdays and during weekends, however primary OC from biomass burning and contemporary secondary OC (from both biogenic and biomass burning emissions) are important fractions as well. Overall, primary biomass burning contributes between 10 and 30% to the carbonaceous aerosol in Sao Paulo. 13C measurements indicate that sugarcane burning could account for up to 15% of OC in the Sao Paulo metropolitan area.

Use of Lead Isotopes to Identify Sources of Metal and Metalloid Contaminants in Atmospheric Aerosol from Mining Operations

PubMed Central

Félix, Omar I.; Csavina, Janae; Field, Jason; Rine, Kyle P.; Sáez, A. Eduardo; Betterton, Eric A.

2014-01-01

Mining operations are a potential source of metal and metalloid contamination by atmospheric particulate generated from smelting activities, as well as from erosion of mine tailings. In this work, we show how lead isotopes can be used for source apportionment of metal and metalloid contaminants from the site of an active copper mine. Analysis of atmospheric aerosol shows two distinct isotopic signatures: one prevalent in fine particles (< 1 μm aerodynamic diameter) while the other corresponds to coarse particles as well as particles in all size ranges from a nearby urban environment. The lead isotopic ratios found in the fine particles are equal to those of the mine that provides the ore to the smelter. Topsoil samples at the mining site show concentrations of Pb and As decreasing with distance from the smelter. Isotopic ratios for the sample closest to the smelter (650 m) and from topsoil at all sample locations, extending to more than 1 km from the smelter, were similar to those found in fine particles in atmospheric dust. The results validate the use of lead isotope signatures for source apportionment of metal and metalloid contaminants transported by atmospheric particulate. PMID:25496740

A Decade of Field Changing Atmospheric Aerosol Research ...

EPA Pesticide Factsheets

Conference: Gordon Research Conference in Atmospheric Chemistry, July 28 – August 2, 2013, VermontPresentation Type: PosterTitle: An Analysis of EPA’s STAR Program and a Decade of Field Changing Research in Atmospheric AerosolsAuthors: Kristina M. Wagstrom1,2, Sherri W. Hunt31Chemical and Biomolecular Engineering, University of Connecticut, Storrs, CT2AAAS Science and Technology Policy Fellow hosted by U.S. Environmental Protection Agency, National Center for Environmental Research3U.S. Environmental Protection Agency, National Center for Environmental ResearchA number of studies in the past decade have transformed the way we think about atmospheric aerosols. The advances include, but are not limited to, source apportionment of organics using aerosol mass spectrometer data, the volatility basis set approach, quantifying isoprene oxidation, and understanding the role of aqueous oxidation of organics on SOA formation. A series of grants funded by EPA just under ten years ago supported many of these advances. These projects make up the body of work awarded under two solicitations released by the EPA’s Science to Achieve Results (STAR) program: “Measurement, Modeling, and Analysis Methods for Airborne Carbonaceous Fine Particulate Matter” (2003) and “Source Apportionment of Particulate Matter” (2004). Our goal is to present the impact of the STAR solicitations and to show how they have pushed the field forward and led to new questions.In particular

Simultaneous aerosol mass spectrometry and chemical ionisation mass spectrometry measurements during a biomass burning event in the UK: insights into nitrate chemistry

NASA Astrophysics Data System (ADS)

Reyes-Villegas, Ernesto; Priestley, Michael; Ting, Yu-Chieh; Haslett, Sophie; Bannan, Thomas; Le Breton, Michael; Williams, Paul I.; Bacak, Asan; Flynn, Michael J.; Coe, Hugh; Percival, Carl; Allan, James D.

2018-03-01

Over the past decade, there has been an increasing interest in short-term events that negatively affect air quality such as bonfires and fireworks. High aerosol and gas concentrations generated from public bonfires or fireworks were measured in order to understand the night-time chemical processes and their atmospheric implications. Nitrogen chemistry was observed during Bonfire Night with nitrogen containing compounds in both gas and aerosol phases and further N2O5 and ClNO2 concentrations, which depleted early next morning due to photolysis of NO3 radicals and ceasing production. Particulate organic oxides of nitrogen (PONs) concentrations of 2.8 µg m-3 were estimated using the m / z 46 : 30 ratios from aerosol mass spectrometer (AMS) measurements, according to previously published methods. Multilinear engine 2 (ME-2) source apportionment was performed to determine organic aerosol (OA) concentrations from different sources after modifying the fragmentation table and it was possible to identify two PON factors representing primary (pPON_ME2) and secondary (sPON_ME2) contributions. A slight improvement in the agreement between the source apportionment of the AMS and a collocated AE-31 Aethalometer was observed after modifying the prescribed fragmentation in the AMS organic spectrum (the fragmentation table) to determine PON sources, which resulted in an r2 = 0.894 between biomass burning organic aerosol (BBOA) and babs_470wb compared to an r2 = 0.861 obtained without the modification. Correlations between OA sources and measurements made using time-of-flight chemical ionisation mass spectrometry with an iodide adduct ion were performed in order to determine possible gas tracers to be used in future ME-2 analyses to constrain solutions. During Bonfire Night, strong correlations (r2) were observed between BBOA and methacrylic acid (0.92), acrylic acid (0.90), nitrous acid (0.86), propionic acid, (0.85) and hydrogen cyanide (0.76). A series of oxygenated species and chlorine compounds showed good correlations with sPON_ME2 and the low volatility oxygenated organic aerosol (LVOOA) factor during Bonfire Night and an event with low pollutant concentrations. Further analysis of pPON_ME2 and sPON_ME2 was performed in order to determine whether these PON sources absorb light near the UV region using an Aethalometer. This hypothesis was tested by doing multilinear regressions between babs_470wb and BBOA, sPON_ME2 and pPON_ME2. Our results suggest that sPON_ME2 does not absorb light at 470 nm, while pPON_ME2 and LVOOA do absorb light at 470 nm. This may inform black carbon (BC) source apportionment studies from Aethalometer measurements, through investigation of the brown carbon contribution to babs_470wb.

SOURCE APPORTIONMENT STUDIES OF PM-2.5 IN TWO CZECH CITIES: POSSIBLE USES IN HEALTH STUDIES

EPA Science Inventory

Aerosol and gas phase air pollutant measurements were made in two cities during an ongoing air pollution-health outcome study in the Czech Republic. Teplice, located in northwestern Bohemia, was selected because the local population was exposed to high air pollution levels. Prac...

SOURCE APPORTIONMENT OF PRIMARY CARBONACEOUS AEROSOL USING THE COMMUNITY MULTISCALE AIR QUALITY MODEL

EPA Science Inventory

A substantial fraction of fine particulate matter (PM) across the United States is composed of carbon, which may be either emitted in particulate form (i.e., primary) or formed in the atmosphere through gas-to-particle conversion processes (i.e., secondary). Primary carbonaceous...

Comparison of source apportionments of PM2.5 using three receptor models (CMB, PMF, and SMP) in Seoul, Korea

NASA Astrophysics Data System (ADS)

Heo, J.; Kim, J. Y.; Kim, S. W.

2017-12-01

We compared source apportionments of PM2.5 in Seoul, Korea by three receptor models, Chemical Mass Balance (CMB), Positive Matrix Factorization (PMF), and Solver for Mixture Problem (SMP). The CMB model can estimate source apportionment with suitable source profiles of emissions, but it is difficult to find location-specific source profiles. In contrary, the multivariate receptor model does not need source profiles, but fundamental natural physical constraints (FNPCs) required for aerosol source apportionment are different in PMF and SMP. Ninety-six PM2.5 daily samples collected at Korea Institute of Science and Technology (KIST) in Seoul, Korea from October 2012 to September 2013 were analyzed in this study. The average PM2.5 mass concentration over the study period was 41.5 ± 27.7 mg m-3 and secondary inorganic species and organic matter were the main chemical species occupying about 73.7% - 87.9% of the PM2.5 mass concentration in all seasons. Secondary sulfate (18.0% - 26.1%), secondary nitrate (12.1% - 28.5%), vehicle (2.9% - 32.9%), biomass burning (13.2% - 21.3%) were identified by all three receptor models as the major sources accounting for approximately 76.3%-82.7% of the total PM2.5 and contributions of main sources represented their seasonality. However, three receptor models showed significant differences, especially for vehicle emission due to their measured/estimated source profiles. In this presentation, more detailed comparisons among CMB, PMF and SMP models will be presented focusing on the source profiles and contributions.

Wood burning pollution in southern Chile: PM2.5 source apportionment using CMB and molecular markers.

PubMed

Villalobos, Ana M; Barraza, Francisco; Jorquera, Héctor; Schauer, James J

2017-06-01

Temuco is a mid-size city representative of severe wood smoke pollution in southern Chile; i.e., ambient 24-h PM 2.5 concentrations have exceeded 150 μg/m 3 in the winter season and the top concentration reached 372 μg/m 3 in 2010. Annual mean concentrations have decreased but are still above 30 μg/m 3 . For the very first time, a molecular marker source apportionment of ambient organic carbon (OC) and PM 2.5 was conducted in Temuco. Primary resolved sources for PM 2.5 were wood smoke (37.5%), coal combustion (4.4%), diesel vehicles (3.3%), dust (2.2%) and vegetative detritus (0.7%). Secondary inorganic PM 2.5 (sulfates, nitrates and ammonium) contributed 4.8% and unresolved organic aerosols (generated from volatile emissions from incomplete wood combustion), including secondary organic aerosols, contributed 47.1%. Adding the contributions of unresolved organic aerosols to those from primary wood smoke implies that wood burning is responsible for 84.6% of the ambient PM 2.5 in Temuco. This predominance of wood smoke is ultimately due to widespread poverty and a lack of efficient household heating methods. The government has been implementing emission abatement policies but achieving compliance with ambient air quality standards for PM 2.5 in southern Chile remains a challenge. Copyright © 2017 Elsevier Ltd. All rights reserved.

pH of Aerosols in a Polluted Atmosphere: Source Contributions to Highly Acidic Aerosol.

PubMed

Shi, Guoliang; Xu, Jiao; Peng, Xing; Xiao, Zhimei; Chen, Kui; Tian, Yingze; Guan, Xinbei; Feng, Yinchang; Yu, Haofei; Nenes, Athanasios; Russell, Armistead G

2017-04-18

Acidity (pH) plays a key role in the physical and chemical behavior of PM 2.5 . However, understanding of how specific PM sources impact aerosol pH is rarely considered. Performing source apportionment of PM 2.5 allows a unique link of sources pH of aerosol from the polluted city. Hourly water-soluble (WS) ions of PM 2.5 were measured online from December 25th, 2014 to June 19th, 2015 in a northern city in China. Five sources were resolved including secondary nitrate (41%), secondary sulfate (26%), coal combustion (14%), mineral dust (11%), and vehicle exhaust (9%). The influence of source contributions to pH was estimated by ISORROPIA-II. The lowest aerosol pH levels were found at low WS-ion levels and then increased with increasing total ion levels, until high ion levels occur, at which point the aerosol becomes more acidic as both sulfate and nitrate increase. Ammonium levels increased nearly linearly with sulfate and nitrate until approximately 20 μg m -3 , supporting that the ammonium in the aerosol was more limited by thermodynamics than source limitations, and aerosol pH responded more to the contributions of sources such as dust than levels of sulfate. Commonly used pH indicator ratios were not indicative of the pH estimated using the thermodynamic model.

Chemical Composition and Source Apportionment of high temporal resolution PM1 data for January-August 2017 in Delhi, India

NASA Astrophysics Data System (ADS)

Bhandari, S.; Wang, D. S.; Gani, S.; Seraj, S.; Arub, Z.; Habib, G.; Apte, J.; Hildebrandt Ruiz, L.

2017-12-01

Exposure to fine particulate matter (PM) poses significant health risks, especially to residents in heavily populated areas. The current understanding of the sources and dynamics of PM pollution in developing countries like India is limited. Delhi, India is the second most populated city in the world that has extremely high winter PM concentrations and frequent severe pollution episodes. This study reports on composition measurements of submicron aerosol at 1 minute time resolution from January to August of 2017, collected at the Indian Institute of Technology Delhi using an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) and black carbon (BC) measurements using an Aethalometer. Source apportionment was conducted on organic and inorganic mass spectra measured by the ACSM and black carbon data measured using Positive Matrix Factorization (PMF). High concentrations of particulate matter were observed with total PM1 at times exceeding 200 µg m-3 in winter. A significant drop in PM1 concentrations was observed in the winter-spring transition. As observed elsewhere, organic species dominated the submicron mass, contributing 60% of the total mass over the duration of the campaign. However, this fractional contribution varied substantially over the day: from 48% early in the morning to 73% late at night. Along with diurnal variation in total PM1 mass loadings, particulate chloride levels also exhibited a strong diurnal cycle, with concentrations as high as 50 µg m-3 observed in the early mornings of January 2017. Literature review on identification of winter chloride sources in Delhi points to local and regional sources such as biomass/open-waste burning and coal combustion. PMF receptor modeling identified several factors with distinct diurnal patterns. While hydrocarbon-like organic aerosol (HOA) factor has the largest mass fraction contribution, PMF results consistently suggest chloride presence as attributable to ammonium chloride. Interestingly, aerosol neutralization characterization shows an apparent acidity of aerosols. These results point to substantial differences in aerosol composition in Indian cities in comparison to cities around the world, especially with regards to the abundance of particulate chloride, and provide insights into the sources of PM1 measured in Delhi.

Overview of the Mathematical and Empirical Receptor Models Workshop (Quail Roost II)

NASA Astrophysics Data System (ADS)

Stevens, Robert K.; Pace, Thompson G.

On 14-17 March 1982, the U.S. Environmental Protection Agency sponsored the Mathematical and Empirical Receptor Models Workshop (Quail Roost II) at the Quail Roost Conference Center, Rougemont, NC. Thirty-five scientists were invited to participate. The objective of the workshop was to document and compare results of source apportionment analyses of simulated and real aerosol data sets. The simulated data set was developed by scientists from the National Bureau of Standards. It consisted of elemental mass data generated using a dispersion model that simulated transport of aerosols from a variety of sources to a receptor site. The real data set contained the mass, elemental, and ionic species concentrations of samples obtained in 18 consecutive 12-h sampling periods in Houston, TX. Some participants performed additional analyses of the Houston filters by X-ray powder diffraction, scanning electron microscopy, or light microscopy. Ten groups analyzed these data sets using a variety of modeling procedures. The results of the modeling exercises were evaluated and structured in a manner that permitted model intercomparisons. The major conclusions and recommendations derived from the intercomparisons were: (1) using aerosol elemental composition data, receptor models can resolve major emission sources, but additional analyses (including light microscopy and X-ray diffraction) significantly increase the number of sources that can be resolved; (2) simulated data sets that contain up to 6 dissimilar emission sources need to be generated, so that different receptor models can be adequately compared; (3) source apportionment methods need to be modified to incorporate a means of apportioning such aerosol species as sulfate and nitrate formed from SO 2 and NO, respectively, because current models tend to resolve particles into chemical species rather than to deduce their sources and (4) a source signature library may be required to be compiled for each airshed in order to improve the resolving capabilities of receptor models.

Metals and metalloids in atmospheric dust: Use of lead isotopic analysis for source apportionment

NASA Astrophysics Data System (ADS)

Felix Villar, Omar I.

Mining activities generate aerosol in a wide range of sizes. Smelting activities produce mainly fine particles (<1 microm). On the other hand, milling, crushing and refining processes, as well tailings management, are significant sources of coarse particles (> 1 microm). The adverse effects of aerosols on human health depend mainly on two key characteristics: size and chemical composition. One of the main objectives of this research is to analyze the size distribution of contaminants in aerosol produced by mining operations. For this purpose, a Micro-Orifice Uniform Deposit Impactor (MOUDI) was utilized. Results from the MOUDI samples show higher concentrations of the toxic elements like lead and arsenic in the fine fraction (<1 microm). Fine particles are more likely to be deposited in the deeper zones of the respiratory system; therefore, they are more dangerous than coarse particles that can be filtered out in the upper respiratory system. Unfortunately, knowing the total concentration of contaminants does not give us enough information to identify the source of contamination. For this reason, lead isotopes have been introduced as fingerprints for source apportionment. Each source of lead has specific isotopic ratios; by knowing these ratios sources can be identified. During this research, lead isotopic ratios were analyzed at different sites and for different aerosol sizes. From these analyses it can be concluded that lead isotopes are a powerful tool to identify sources of lead. Mitigation strategies could be developed if the source of contamination is well defined. Environmental conditions as wind speed, wind direction, relative humidity and precipitation have an important role in the concentration of atmospheric dust. Dry environments with low relative humidity are ideal for the transport of aerosols. Results obtained from this research show the relationship between dust concentrations and meteorological parameters. Dust concentrations are highly correlated with relative humidity and wind speed. With all the data collected on site and the analysis of the meteorological parameters, models can be develop to predict the transport of particles as well as the concentration of contaminants at a specific point. These models were developed and are part of the results shown in this dissertation.

Biomass burning in the Amazon region: Aerosol source apportionment and associated health risk assessment

NASA Astrophysics Data System (ADS)

de Oliveira Alves, Nilmara; Brito, Joel; Caumo, Sofia; Arana, Andrea; de Souza Hacon, Sandra; Artaxo, Paulo; Hillamo, Risto; Teinilä, Kimmo; Batistuzzo de Medeiros, Silvia Regina; de Castro Vasconcellos, Pérola

2015-11-01

The Brazilian Amazon represents about 40% of the world's remaining tropical rainforest. However, human activities have become important drivers of disturbance in that region. The majority of forest fire hotspots in the Amazon arc due to deforestation are impacting the health of the local population of over 10 million inhabitants. In this study we characterize western Amazonia biomass burning emissions through the quantification of 14 Polycyclic Aromatic Hydrocarbons (PAHs), Organic Carbon, Elemental Carbon and unique tracers of biomass burning such as levoglucosan. From the PAHs dataset a toxic equivalence factor is calculated estimating the carcinogenic and mutagenic potential of biomass burning emissions during the studied period. Peak concentration of PM10 during the dry seasons was observed to reach 60 μg m-3 on the 24 h average. Conversely, PM10 was relatively constant throughout the wet season indicating an overall stable balance between aerosol sources and sinks within the filter sampling resolution. Similar behavior is identified for OC and EC components. Levoglucosan was found in significant concentrations (up to 4 μg m-3) during the dry season. Correspondingly, the estimated lung cancer risk calculated during the dry seasons largely exceeded the WHO health-based guideline. A source apportionment study was carried out through the use of Absolute Principal Factor Analysis (APFA), identifying a three-factor solution. The biomass burning factor is found to be the dominating aerosol source, having 75.4% of PM10 loading. The second factor depicts an important contribution of several PAHs without a single source class and therefore was considered as mixed sources factor, contributing to 6.3% of PM10. The third factor was mainly associated with fossil fuel combustion emissions, contributing to 18.4% of PM10. This work enhances the knowledge of aerosol sources and its impact on climate variability and local population, on a site representative of the deforestation which occupies a significant fraction of the Amazon basin.

Contribution of regional-scale fire events to ozone and PM2.5 air quality estimated by photochemical modeling approaches

NASA Astrophysics Data System (ADS)

Baker, K. R.; Woody, M. C.; Tonnesen, G. S.; Hutzell, W.; Pye, H. O. T.; Beaver, M. R.; Pouliot, G.; Pierce, T.

2016-09-01

Two specific fires from 2011 are tracked for local to regional scale contribution to ozone (O3) and fine particulate matter (PM2.5) using a freely available regulatory modeling system that includes the BlueSky wildland fire emissions tool, Spare Matrix Operator Kernel Emissions (SMOKE) model, Weather and Research Forecasting (WRF) meteorological model, and Community Multiscale Air Quality (CMAQ) photochemical grid model. The modeling system was applied to track the contribution from a wildfire (Wallow) and prescribed fire (Flint Hills) using both source sensitivity and source apportionment approaches. The model estimated fire contribution to primary and secondary pollutants are comparable using source sensitivity (brute-force zero out) and source apportionment (Integrated Source Apportionment Method) approaches. Model estimated O3 enhancement relative to CO is similar to values reported in literature indicating the modeling system captures the range of O3 inhibition possible near fires and O3 production both near the fire and downwind. O3 and peroxyacetyl nitrate (PAN) are formed in the fire plume and transported downwind along with highly reactive VOC species such as formaldehyde and acetaldehyde that are both emitted by the fire and rapidly produced in the fire plume by VOC oxidation reactions. PAN and aldehydes contribute to continued downwind O3 production. The transport and thermal decomposition of PAN to nitrogen oxides (NOX) enables O3 production in areas limited by NOX availability and the photolysis of aldehydes to produce free radicals (HOX) causes increased O3 production in NOX rich areas. The modeling system tends to overestimate hourly surface O3 at routine rural monitors in close proximity to the fires when the model predicts elevated fire impacts on O3 and Hazard Mapping System (HMS) data indicates possible fire impact. A sensitivity simulation in which solar radiation and photolysis rates were more aggressively attenuated by aerosol in the plume reduced model O3 but does not eliminate this bias. A comparison of model predicted daily average speciated PM2.5 at surface rural routine network sites when the model predicts fire impacts from either of these fires shows a tendency toward overestimation of PM2.5 organic aerosol in close proximity to these fires. The standard version of the CMAQ treats primarily emitted organic aerosol as non-volatile. An alternative approach for treating organic aerosol as semi-volatile resulted in lower PM2.5 organic aerosol from these fires but does not eliminate the bias. Future work should focus on modeling specific fire events that are well characterized in terms of size, emissions, and have extensive measurements taken near the fire and downwind to better constrain model representation of important physical and chemical processes (e.g. aerosol photolysis attenuation and organic aerosol treatment) related to wild and prescribed fires.

Aerosol carbon isotope composition over Baltic Sea

NASA Astrophysics Data System (ADS)

Garbaras, Andrius; Pabedinskas, Algirdas; Masalaite, Agne; Petelski, Tomasz; Gorokhova, Elena; Sapolaite, Justina; Ezerinskis, Zilvinas; Remeikis, Vidmantas

2017-04-01

Particulate carbonaceous matter is significant contributor to ambient particulate matter originating from intervening sources which contribution is difficult to quantify due to source diversity, chemical complexity and processes during atmospheric transport. Carbon isotope analysis can be extremely useful in source apportionment of organic matter due to the unique isotopic signatures associated with anthropocentric (fossil fuel), continental (terrestrial plants) and marine sources, and is particularly effective when these sources are mixed (Ceburnis et al., 2011;Ceburnis et al., 2016). We will present the isotope ratio measurement results of aerosol collected during the cruise in the Baltic Sea. Sampling campaign of PM10 and size segregated aerosol particles was performed on the R/V "Oceania" in October 2015. Air mass back trajectories were prevailing both from the continental and marine areas during the sampling period. The total carbon concentration varied from 1 µg/m3 to 8 µg/m3. Two end members (δ13C = -25‰ and δ13C = -28 ‰ ) were established from the total stable carbon isotope analysis in PM10 fraction. δ13C analysis in size segregated aerosol particles revealed δ13C values being highest in the 1 - 2.5 µm range (δ13C = -24.9 ‰ ) during continental transport, while lowest TC δ13C values (δ13C ≈ -27 ‰ ) were detected in the size range D50 <1 µm during stormy weather when air mass trajectory prevailed from the western direction. These measurements revealed that simplified isotope mixing model can not be applied for the aerosol source apportionment (Masalaite et al., 2015) in the perturbed marine environment. Additionally, concentration of bacteria and fungi were measured in size segregated and PM10 aerosol fraction. We were able to relate aerosol source δ13C end members with the abundance of bacteria and fungi over Baltic Sea combining air mass trajectories, stable isotope data, fungi and bacteria concentrations. Ceburnis, D., Garbaras, A., Szidat, S., Rinaldi, M., Fahrni, S., Perron, N., Wacker, L., Leinert, S., Remeikis, V., and Facchini, M.: Quantification of the carbonaceous matter origin in submicron marine aerosol by 13 C and 14 C isotope analysis, Atmospheric Chemistry and Physics, 11, 8593-8606, 2011. Ceburnis, D., Masalaite, A., Ovadnevaite, J., Garbaras, A., Remeikis, V., Maenhaut, W., Claeys, M., Sciare, J., Baisnée, D., and O'Dowd, C. D.: Stable isotopes measurements reveal dual carbon pools contributing to organic matter enrichment in marine aerosol, Scientific Reports, 6, 2016. Masalaite, A., Remeikis, V., Garbaras, A., Dudoitis, V., Ulevicius, V., and Ceburnis, D.: Elucidating carbonaceous aerosol sources by the stable carbon δ13C TC ratio in size-segregated particles, Atmospheric Research, 158, 1-12, 2015.

Modelling winter organic aerosol at the European scale with CAMx: evaluation and source apportionment with a VBS parameterization based on novel wood burning smog chamber experiments

NASA Astrophysics Data System (ADS)

Ciarelli, Giancarlo; Aksoyoglu, Sebnem; El Haddad, Imad; Bruns, Emily A.; Crippa, Monica; Poulain, Laurent; Äijälä, Mikko; Carbone, Samara; Freney, Evelyn; O'Dowd, Colin; Baltensperger, Urs; Prévôt, André S. H.

2017-06-01

We evaluated a modified VBS (volatility basis set) scheme to treat biomass-burning-like organic aerosol (BBOA) implemented in CAMx (Comprehensive Air Quality Model with extensions). The updated scheme was parameterized with novel wood combustion smog chamber experiments using a hybrid VBS framework which accounts for a mixture of wood burning organic aerosol precursors and their further functionalization and fragmentation in the atmosphere. The new scheme was evaluated for one of the winter EMEP intensive campaigns (February-March 2009) against aerosol mass spectrometer (AMS) measurements performed at 11 sites in Europe. We found a considerable improvement for the modelled organic aerosol (OA) mass compared to our previous model application with the mean fractional bias (MFB) reduced from -61 to -29 %. We performed model-based source apportionment studies and compared results against positive matrix factorization (PMF) analysis performed on OA AMS data. Both model and observations suggest that OA was mainly of secondary origin at almost all sites. Modelled secondary organic aerosol (SOA) contributions to total OA varied from 32 to 88 % (with an average contribution of 62 %) and absolute concentrations were generally under-predicted. Modelled primary hydrocarbon-like organic aerosol (HOA) and primary biomass-burning-like aerosol (BBPOA) fractions contributed to a lesser extent (HOA from 3 to 30 %, and BBPOA from 1 to 39 %) with average contributions of 13 and 25 %, respectively. Modelled BBPOA fractions were found to represent 12 to 64 % of the total residential-heating-related OA, with increasing contributions at stations located in the northern part of the domain. Source apportionment studies were performed to assess the contribution of residential and non-residential combustion precursors to the total SOA. Non-residential combustion and road transportation sector contributed about 30-40 % to SOA formation (with increasing contributions at urban and near industrialized sites), whereas residential combustion (mainly related to wood burning) contributed to a larger extent, around 60-70 %. Contributions to OA from residential combustion precursors in different volatility ranges were also assessed: our results indicate that residential combustion gas-phase precursors in the semivolatile range (SVOC) contributed from 6 to 30 %, with higher contributions predicted at stations located in the southern part of the domain. On the other hand, the oxidation products of higher-volatility precursors (the sum of intermediate-volatility compounds (IVOCs) and volatile organic compounds (VOCs)) contribute from 15 to 38 % with no specific gradient among the stations. Although the new parameterization leads to a better agreement between model results and observations, it still under-predicts the SOA fraction, suggesting that uncertainties in the new scheme and other sources and/or formation mechanisms remain to be elucidated. Moreover, a more detailed characterization of the semivolatile components of the emissions is needed.

Apportionment of sources of fine and coarse particles in four major Australian cities by positive matrix factorisation

NASA Astrophysics Data System (ADS)

Chan, Yiu-Chung; Cohen, David D.; Hawas, Olga; Stelcer, Eduard; Simpson, Rod; Denison, Lyn; Wong, Neil; Hodge, Mary; Comino, Eva; Carswell, Stewart

In this study, 437 days of 6-daily, 24-h samples of PM 2.5, PM 2.5-10 and PM 10 were collected over a 12-month period during 2003-2004 in Melbourne, Sydney, Brisbane and Adelaide. The elemental, ionic and polycyclic aromatic hydrocarbon composition of the particles were determined. Source apportionment was carried out by using the positive matrix factorisation software (PMF2). Eight factors were identified for the fine particle samples including 'motor vehicles', 'industry', 'other combustion sources', 'ammonium sulphates', 'nitrates', 'marine aerosols', 'chloride depleted marine aerosols' and 'crustal/soil dust'. On average combustion sources, secondary nitrates/sulphates and natural origin dust contributed about 46%, 25% and 26% of the mass of the fine particle samples, respectively. 'Crustal/soil dust', 'marine aerosols', 'nitrates' and 'road side dust' were the four factors identified for the coarse particle samples. On average natural origin dust contributed about 76% of the mass of the coarse particle samples. The contributions of the sources to the sample mass basically reflect the emission source characteristics of the sites. Secondary sulphates and nitrates were found to spread out evenly within each city. The average contribution of secondary nitrates to fine particles was found to be rather uniform in different seasons, rather than higher in winter as found in other studies. This could be due to the low humidity conditions in winter in most of the Australian cities which made the partitioning of the particle phase less favourable in the NH 4NO 3 equilibrium system. A linear relationship was found between the average contribution of marine aerosols and the distance of the site from the bay side. Wind erosion was found associated with higher contribution of crustal dust on average and episodes of elevated concentration of coarse particles in spring and summer.

Source Apportionment of Ambient Fine Particulate Matter in Dearborn, Michigan, using Hourly Resolved PM Chemical Composition Data

EPA Science Inventory

High time-resolution aerosol sampling was conducted for one month during July–August 2007 in Dearborn, MI, a non-attainment area for fine particulate matter (PM2.5) National Ambient Air Quality Standards (NAAQS). Measurements of more than 30 PM2.5 species were made using a suite o...

Source Apportionment of Elemental Carbon in Beijing, China: Insights from Radiocarbon and Organic Marker Measurements.

PubMed

Zhang, Yan-Lin; Schnelle-Kreis, Jürgen; Abbaszade, Gülcin; Zimmermann, Ralf; Zotter, Peter; Shen, Rong-rong; Schäfer, Klaus; Shao, Longyi; Prévôt, André S H; Szidat, Sönke

2015-07-21

Elemental carbon (EC) or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In this study, radiocarbon ((14)C) based source apportionment is used to distinguish between fossil fuel and biomass burning sources of EC isolated from aerosol filter samples collected in Beijing from June 2010 to May 2011. The (14)C results demonstrate that EC is consistently dominated by fossil-fuel combustion throughout the whole year with a mean contribution of 79% ± 6% (ranging from 70% to 91%), though EC has a higher mean and peak concentrations in the cold season. The seasonal molecular pattern of hopanes (i.e., a class of organic markers mainly emitted during the combustion of different fossil fuels) indicates that traffic-related emissions are the most important fossil source in the warm period and coal combustion emissions are significantly increased in the cold season. By combining (14)C based source apportionment results and picene (i.e., an organic marker for coal emissions) concentrations, relative contributions from coal (mainly from residential bituminous coal) and vehicle to EC in the cold period were estimated as 25 ± 4% and 50 ± 7%, respectively, whereas the coal combustion contribution was negligible or very small in the warm period.

Establishing the origin of particulate matter across Europe

NASA Astrophysics Data System (ADS)

Schaap, Martijn; Kranenburg, Richard; Hendriks, Carlijn; Kuenen, Jeroen

2016-04-01

Exposure to particulate matter (PM) in ambient air leads to adverse health effects. To design cost effective mitigation strategies, a thorough understanding of the sources of particulate matter is crucial. In this paper we like to provide an overview of recent source apportionment studies aimed at PM and its precursors carried out at TNO. The source apportionment module that tracks the origin of modelled particulate matter distributions throughout a LOTOS-EUROS simulation will be explained. To optimally apply this technology dedicated emission inventories, e.g. fuel type specific, need to be generated. Applications to Europe shows that in northwestern Europe the contribution of transport and agricultural emissions dominate the PM mass concentrations, especially during episodic events. In eastern Europe, the domestic and energy sector are much more important. In southern Europe the picture is more mixed, although the frequent high levels of desert dust stand out. Evaluation of the source allocation against experimental data and PMF analyses is challenging as there is only a limited availability of source specific tracers or factors that can be used for direct comparison. Nonetheless, for the available tracers such as vanadium for heavy fuel oil combustion an evaluation is very well possible. The source apportionment technique can also be used to interpret particulate matter formation efficiencies. It will be shown that the conversion rates for the secondary inorganic aerosol precursors (NOx, NH3 and SO2) have changed during the last 20 years. A particular problem is related to the fact that CTMs systematically underestimate observed PM levels, which means that the contribution of certain source categories (natural, agriculture, combustion) are underestimated. Future developments needed to improve the source apportionment information concerning process knowledge, data assimilation as well as model implementation will be discussed. Specific challenges concerning the underlying emission information will be highlighted.

Long-term chemical analysis and organic aerosol source apportionment at nine sites in central Europe: source identification and uncertainty assessment

NASA Astrophysics Data System (ADS)

Daellenbach, Kaspar R.; Stefenelli, Giulia; Bozzetti, Carlo; Vlachou, Athanasia; Fermo, Paola; Gonzalez, Raquel; Piazzalunga, Andrea; Colombi, Cristina; Canonaco, Francesco; Hueglin, Christoph; Kasper-Giebl, Anne; Jaffrezo, Jean-Luc; Bianchi, Federico; Slowik, Jay G.; Baltensperger, Urs; El-Haddad, Imad; Prévôt, André S. H.

2017-11-01

Long-term monitoring of organic aerosol is important for epidemiological studies, validation of atmospheric models, and air quality management. In this study, we apply a recently developed filter-based offline methodology using an aerosol mass spectrometer (AMS) to investigate the regional and seasonal differences of contributing organic aerosol sources. We present offline AMS measurements for particulate matter smaller than 10 µm at nine stations in central Europe with different exposure characteristics for the entire year of 2013 (819 samples). The focus of this study is a detailed source apportionment analysis (using positive matrix factorization, PMF) including in-depth assessment of the related uncertainties. Primary organic aerosol (POA) is separated in three components: hydrocarbon-like OA related to traffic emissions (HOA), cooking OA (COA), and biomass burning OA (BBOA). We observe enhanced production of secondary organic aerosol (SOA) in summer, following the increase in biogenic emissions with temperature (summer oxygenated OA, SOOA). In addition, a SOA component was extracted that correlated with an anthropogenic secondary inorganic species that is dominant in winter (winter oxygenated OA, WOOA). A factor (sulfur-containing organic, SC-OA) explaining sulfur-containing fragments (CH3SO2+), which has an event-driven temporal behaviour, was also identified. The relative yearly average factor contributions range from 4 to 14 % for HOA, from 3 to 11 % for COA, from 11 to 59 % for BBOA, from 5 to 23 % for SC-OA, from 14 to 27 % for WOOA, and from 15 to 38 % for SOOA. The uncertainty of the relative average factor contribution lies between 2 and 12 % of OA. At the sites north of the alpine crest, the sum of HOA, COA, and BBOA (POA) contributes less to OA (POA / OA = 0.3) than at the southern alpine valley sites (0.6). BBOA is the main contributor to POA with 87 % in alpine valleys and 42 % north of the alpine crest. Furthermore, the influence of primary biological particles (PBOAs), not resolved by PMF, is estimated and could contribute significantly to OA in PM10.

Source apportionment of PM2.5 carbonaceous aerosol in Baghdad, Iraq

NASA Astrophysics Data System (ADS)

Hamad, Samera Hussein; Schauer, James Jay; Heo, Jongbae; Kadhim, Ahmed K. H.

2015-04-01

Baghdad is the second largest city in the Middle East and suffers from severe air quality degradation due to the high levels of the atmospheric particulate matter (PM). Limited information exists regarding the sources of PM in Baghdad, and the lack of information on sources inhibits the development of control strategies to reduce air pollution. To better understand the nature of fine particulate matter (PM2.5) in Baghdad and the Middle East, a one year sampling campaign to collect PM2.5 was conducted from September 2012 through September 2013, missing August 2013 samples due to the security situation. 24-hour integrated samples collected on a 1-in-6 day schedule were analyzed for the major components, and monthly average samples were analyzed by gas chromatography mass spectrometry (GCMS) methods to measure particle-phase organic molecular markers. The results of organic molecular markers were used in a chemical mass balance (CMB) model to quantify the sources of PM2.5 organic carbon (OC) and PM2.5 mass. Primary sources accounted for 44% of the measured PM2.5, and secondary sources were estimated to make up 28% of the measured PM2.5. Picene, a tracer of coal combustion detected in Baghdad where there is no evidence for coal combustion, can be attributed to burning crude oil and other low quality fuels in Baghdad. Source apportionment results showed that the dominant sources of the carbonaceous aerosols in Baghdad are gasoline (37 ± 6%) and diesel engines (17 ± 3%) which can be attributed to the extensive use of gasoline and diesel powered generators in Baghdad. Wood burning and residual oil combustion contributed to 5 ± 0.4 and 1 ± 0.2% respectively of OC. The unresolved sources contributed to 42 ± 19% of the OC which represented the secondary organic aerosol (SOA) and the unidentified sources.

Characteristics and source apportionment of black carbon aerosols over an urban site.

PubMed

Rajesh, T A; Ramachandran, S

2017-03-01

Aethalometer based source apportionment model using the measured aerosol absorption coefficients at different wavelengths is used to apportion the contribution of fossil fuel and wood burning sources to the total black carbon (BC) mass concentration. Temporal and seasonal variabilities in BC mass concentrations, equivalent BC from fossil fuel (BC f f ), and wood burning (BC w b ) are investigated over an urban location in western India during January 2014 to December 2015. BC, BC f f , and BC w b mass concentrations exhibit strong diurnal variation and are mainly influenced by atmospheric dynamics. BC f f was higher by a factor of 2-4 than BC w b and contributes maximum to BC mass throughout the day, confirming consistent anthropogenic activities. Diurnal contribution of BC f f and BC w b exhibits opposite variation due to differences in emission sources over Ahmedabad. Night time BC values are about a factor of 1.4 higher than day time BC values. The annual mean percentage contributions of day time and night time are 42 and 58 %, respectively. BC, BC f f , and BC w b mass concentrations exhibit large and significant variations during morning, afternoon, evening, and night time. During afternoon, mass concentration values are minimum throughout the year because of the fully evolved boundary layer and reduced anthropogenic activities. BC exhibits a strong seasonal variability with postmonsoon high (8.3 μg m -3 ) and monsoon low (1.9 μg m -3 ). Annual mean BC f f and BC w b contributions are 80 and 20 %, respectively, to total BC, which suggests that major contribution of BC in Ahmedabad comes from fossil fuel emissions. The results show that the study location is dominated by fossil fuel combustion as compared to the emissions from wood burning. The results obtained represent a regional value over an urban regime which can be used as inputs on source apportionment to model BC emissions in regional and global climate models.

Source apportionment of airborne particulate matter using organic compounds as tracers

NASA Astrophysics Data System (ADS)

Schauer, James J.; Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

A chemical mass balance receptor model based on organic compounds has been developed that relates source contributions to airborne fine particle mass concentrations. Source contributions to the concentrations of specific organic compounds are revealed as well. The model is applied to four air quality monitoring sites in southern California using atmospheric organic compound concentration data and source test data collected specifically for the purpose of testing this model. The contributions of up to nine primary particle source types can be separately identified in ambient samples based on this method, and approximately 85% of the organic fine aerosol is assigned to primary sources on an annual average basis. The model provides information on source contributions to fine mass concentrations, fine organic aerosol concentrations and individual organic compound concentrations. The largest primary source contributors to fine particle mass concentrations in Los Angeles are found to include diesel engine exhaust, paved road dust, gasoline-powered vehicle exhaust, plus emissions from food cooking and wood smoke, with smaller contribution from tire dust, plant fragments, natural gas combustion aerosol, and cigarette smoke. Once these primary aerosol source contributions are added to the secondary sulfates, nitrates and organics present, virtually all of the annual average fine particle mass at Los Angeles area monitoring sites can be assigned to its source.

Comparison of PM10 concentrations and metal content in three different sites of the Venice Lagoon: an analysis of possible aerosol sources.

PubMed

Contini, Daniele; Belosi, Franco; Gambaro, Andrea; Cesari, Daniela; Stortini, Angela Maria; Bove, Maria Chiara

2012-01-01

The Venice Lagoon is exposed to atmospheric pollutants from industrial activities, thermoelectric power plants, petrochemical plants, incinerator, domestic heating, ship traffic, glass factories and vehicular emissions on the mainland. In 2005, construction began on the mobile dams (MOSE), one dam for each channel connecting the lagoon to the Adriatic Sea as a barrier against high tide. These construction works could represent an additional source of pollutants. PM10 samples were taken on random days between 2007 and 2010 at three different sites: Punta Sabbioni, Chioggia and Malamocco, located near the respective dam construction worksites. Chemical analyses of V, Cr, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl and Pb in PM10 samples were performed by Inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) and results were used to identify the main aerosol sources. The correlation of measured data with meteorology, and source apportionment, failed to highlight a contribution specifically associated to the emissions of the MOSE construction works. The comparison of the measurements at the three sites showed a substantial homogeneity of metal concentrations in the area. Source apportionment with principal component analysis (PCA) and positive matrix factorization (PMF) showed that a four principal factors model could describe the sources of metals in PM10. Three of them were assigned to specific sources in the area and one was characterised as a source of mixed origin (anthropogenic and crustal). A specific anthropogenic source of PM10 rich in Ni and Cr, active at the Chioggia site, was also identified.

Nested Source Apportionment of Secondary Inorganic Aerosol over Yangtze River Delta during Heavy Haze Episodes

NASA Astrophysics Data System (ADS)

Luo, L.; Cheng, Z.

2017-12-01

Secondary inorganic aerosols (SNA), i.e., sulfate, nitrate and ammonium, account for over 50% of fine particulate matter (PM2.5) during heavy haze episodes over Yangtze River Delta (YRD) region of China. Understanding the origin and transport of SNA is crucial for alleviating haze pollution over YRD. The long range transport from outer-YRD regions had significant influence on SNA during haze episodes over YRD, especially in winter. However, previous studies only using single domain for source analysis are limited on quantifying the local and transported sources in province scale altogether. In this study, the Integrated Source Apportionment Method (ISAM) based on the Weather Research and Forecasting and Community Multi-scale Air Quality (WRF-CMAQ) models was performed to two nested domains, one covering east of China and the other embracing YRD, for source apportionment of SNA in YRD during January, 2015. The results indicated that the outer-YRD transport mainly from upwind northwestern provinces, Shandong and Henan, was the dominant contributor accounting for 36.2% of sulfate during pollution episodes. For nitrate, inner-YRD and outer-YRD transport were the two evenly major regional sources, contributing 51.9% of nitrate during hazes. However, local accumulation was the first contributor accounting for 73.9% of ammonium. The long lifetime of formation process for sulfate and nitrate caused the conspicuous transport effect driven by wind when adjacent regions under severe pollution. Although the total effects of long and short distant transport played a major role for the level of sulfate and nitrate, the extent of contribution from local accumulation was similar with them even larger in province scale. Industry followed by power plant were two principal sources of sulfate for all three types of regional contribution. The main sectoral sources of nitrate were industry and transport for local accumulation while power plant besides them for inner-YRD and outer-YRD transport. For ammonium, volatile sources were major origin for local accumulation while agriculture for inner-YRD transport. These results demonstrate the importance for outer-YRD control during haze episodes for sulfate and nitrate while local emission control for ammonium in YRD.

Source apportionment of airborne particulate matter using organic compounds as tracers

NASA Astrophysics Data System (ADS)

Schauer, James J.; Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

A chemical mass balance receptor model based on organic compounds has been developed that relates sours; contributions to airborne fine particle mass concentrations. Source contributions to the concentrations of specific organic compounds are revealed as well. The model is applied to four air quality monitoring sites in southern California using atmospheric organic compound concentration data and source test data collected specifically for the purpose of testing this model. The contributions of up to nine primary particle source types can be separately identified in ambient samples based on this method, and approximately 85% of the organic fine aerosol is assigned to primary sources on an annual average basis. The model provides information on source contributions to fine mass concentrations, fine organic aerosol concentrations and individual organic compound concentrations. The largest primary source contributors to fine particle mass concentrations in Los Angeles are found to include diesel engine exhaust, paved road dust, gasoline-powered vehicle exhaust, plus emissions from food cooking and wood smoke, with smaller contribution:; from tire dust, plant fragments, natural gas combustion aerosol, and cigarette smoke. Once these primary aerosol source contributions are added to the secondary sulfates, nitrates and organics present, virtually all of the annual average fine particle mass at Los Angeles area monitoring sites can be assigned to its source.

Organic aerosol source apportionment in London 2013 with ME-2: exploring the solution space with annual and seasonal analysis

NASA Astrophysics Data System (ADS)

Reyes-Villegas, Ernesto; Green, David C.; Priestman, Max; Canonaco, Francesco; Coe, Hugh; Prévôt, André S. H.; Allan, James D.

2016-12-01

The multilinear engine (ME-2) factorization tool is being widely used following the recent development of the Source Finder (SoFi) interface at the Paul Scherrer Institute. However, the success of this tool, when using the a value approach, largely depends on the inputs (i.e. target profiles) applied as well as the experience of the user. A strategy to explore the solution space is proposed, in which the solution that best describes the organic aerosol (OA) sources is determined according to the systematic application of predefined statistical tests. This includes trilinear regression, which proves to be a useful tool for comparing different ME-2 solutions. Aerosol Chemical Speciation Monitor (ACSM) measurements were carried out at the urban background site of North Kensington, London from March to December 2013, where for the first time the behaviour of OA sources and their possible environmental implications were studied using an ACSM. Five OA sources were identified: biomass burning OA (BBOA), hydrocarbon-like OA (HOA), cooking OA (COA), semivolatile oxygenated OA (SVOOA) and low-volatility oxygenated OA (LVOOA). ME-2 analysis of the seasonal data sets (spring, summer and autumn) showed a higher variability in the OA sources that was not detected in the combined March-December data set; this variability was explored with the triangle plots f44 : f43 f44 : f60, in which a high variation of SVOOA relative to LVOOA was observed in the f44 : f43 analysis. Hence, it was possible to conclude that, when performing source apportionment to long-term measurements, important information may be lost and this analysis should be done to short periods of time, such as seasonally. Further analysis on the atmospheric implications of these OA sources was carried out, identifying evidence of the possible contribution of heavy-duty diesel vehicles to air pollution during weekdays compared to those fuelled by petrol.

Source apportionment of speciated PM10 in the United Kingdom in 2008: Episodes and annual averages

NASA Astrophysics Data System (ADS)

Redington, A. L.; Witham, C. S.; Hort, M. C.

2016-11-01

The Lagrangian atmospheric dispersion model NAME (Numerical Atmospheric-dispersion Modelling Environment), has been used to simulate the formation and transport of PM10 over North-West Europe in 2008. The model has been evaluated against UK measurement data and been shown to adequately represent the observed PM10 at rural and urban sites on a daily basis. The Lagrangian nature of the model allows information on the origin of pollutants (and hence their secondary products) to be retained to allow attribution of pollutants at receptor sites back to their sources. This source apportionment technique has been employed to determine whether the different components of the modelled PM10 have originated from UK, shipping, European (excluding the UK) or background sources. For the first time this has been done to evaluate the composition during periods of elevated PM10 as well as the annual average composition. The episode data were determined by selecting the model data for each hour when the corresponding measurement data was >50 μg/m3. All the modelled sites show an increase in European pollution contribution and a decrease in the background contribution in the episode case compared to the annual average. The European contribution is greatest in southern and eastern parts of the UK and decreases moving northwards and westwards. Analysis of the speciated attribution data over the selected sites reveals that for 2008, as an annual average, the top three contributors to total PM10 are UK primary PM10 (17-25%), UK origin nitrate aerosol (18-21%) and background PM10 (11-16%). Under episode conditions the top three contributors to modelled PM10 are UK origin nitrate aerosol (12-33%), European origin nitrate aerosol (11-19%) and UK primary PM10 (12-18%).

Source apportionment of aerosol particles near a steel plant by electron microscopy.

PubMed

Ebert, Martin; Müller-Ebert, Dörthe; Benker, Nathalie; Weinbruch, Stephan

2012-12-01

The size, morphology and chemical composition of 37,715 individual particles collected over 22 sampling days in the vicinity of a large integrated steel production were studied by scanning and transmission electron microscopy. Based on the morphology, chemistry and beam stability the particles were classified into the following fourteen groups: silicates, sea salt, calcium sulfates, calcium carbonates, carbonate-silicate mixtures, sulfate-silicate mixtures, iron oxides, iron mixtures, metal oxide-metals, complex secondary particles, soot, Cl-rich particles, P-rich particles, and other particles. The majority of iron oxide (≈85%) and metal oxide-metal (≈70%) particles as well as ≈20% of the silicate particles are fly ashes from high temperature processes. The emissions from the steel work are dominated by iron oxide particles. For source apportionment, seven source categories and two sectors of local wind direction (industrial and urban background) were distinguished. In both sectors PM₁₀ consists of four major source categories: 35% secondary, 20% industrial, 17% soil and 16% soot in the urban background sector compared to 45% industrial, 20% secondary, 13% soil, and 9% soot in the industrial sector. As the secondary and the soot components are higher in the urban background sector than in the industrial sector, it is concluded that both components predominantly originate from urban background sources (traffic, coal burning, and domestic heating). Abatement measures should not only focus on the steel work but should also include the urban background aerosol.

Source apportionment of PM10 and PM2.5 air pollution, and possible impacts of study characteristics in South Korea.

PubMed

Ryou, Hyoung Gon; Heo, Jongbae; Kim, Sun-Young

2018-09-01

Studies of source apportionment (SA) for particulate matter (PM) air pollution have enhanced understanding of dominant pollution sources and quantification of their contribution. Although there have been many SA studies in South Korea over the last two decades, few studies provided an integrated understanding of PM sources nationwide. The aim of this study was to summarize findings of PM SA studies of South Korea and to explore study characteristics. We selected studies that estimated sources of PM 10 and PM 2.5 performed for 2000-2017 in South Korea using Positive Matrix Factorization and Chemical Mass Balance. We reclassified the original PM sources identified in each study into seven categories: motor vehicle, secondary aerosol, soil dust, biomass/field burning, combustion/industry, natural source, and others. These seven source categories were summarized by using frequency and contribution across four regions, defined by northwest, west, southeast, and southwest regions, by PM 10 and PM 2.5 . We also computed the population-weighted mean contribution of each source category. In addition, we compared study features including sampling design, sampling and lab analysis methods, chemical components, and the inclusion of Asian dust days. In the 21 selected studies, all six PM 10 studies identified motor vehicle, soil dust, and combustion/industry, while all 15 PM 2.5 studies identified motor vehicle and soil dust. Different from the frequency, secondary aerosol produced a large contribution to both PM 10 and PM 2.5 . Motor vehicle contributed highly to both, whereas the contribution of combustion/industry was high for PM 10 . The population-weighted mean contribution was the highest for the motor vehicle and secondary aerosol sources for both PM10 and PM2.5. However, these results were based on different subsets of chemical speciation data collected at a single sampling site, commonly in metropolitan areas, with short overlap and measured by different lab analysis methods. We found that motor vehicle and secondary aerosol were the most common and influential sources for PM in South Korea. Our study, however, suggested a caution to understand SA findings from heterogeneous study features for study designs and input data. Copyright © 2018. Published by Elsevier Ltd.

Chemical composition, sources and secondary processes of aerosols in Baoji city of northwest China

NASA Astrophysics Data System (ADS)

Wang, Y. C.; Huang, R.-J.; Ni, H. Y.; Chen, Y.; Wang, Q. Y.; Li, G. H.; Tie, X. X.; Shen, Z. X.; Huang, Y.; Liu, S. X.; Dong, W. M.; Xue, P.; Fröhlich, R.; Canonaco, F.; Elser, M.; Daellenbach, K. R.; Bozzetti, C.; El Haddad, I.; Prévôt, A. S. H.; Canagaratna, M. R.; Worsnop, D. R.; Cao, J. J.

2017-06-01

Particulate air pollution is a severe environmental problem in China, affecting visibility, air quality, climate and human health. However, previous studies focus mainly on large cities such as Beijing, Shanghai, and Guangzhou. In this study, an Aerodyne Aerosol Chemical Speciation Monitor was deployed in Baoji, a middle size inland city in northwest China from 26 February to 27 March 2014. The non-refractory submicron aerosol (NR-PM1) was dominated by organics (55%), followed by sulfate (16%), nitrate (15%), ammonium (11%) and chloride (3%). A source apportionment of the organic aerosol (OA) was performed with the Sofi (Source Finder) interface of ME-2 (Multilinear Engine), and six main sources/factors were identified and classified as hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), coal combustion OA (CCOA), less oxidized oxygenated OA (LO-OOA) and more oxidized oxygenated OA (MO-OOA), which contributed 20%, 14%, 13%, 9%, 23% and 21% of total OA, respectively. The contribution of secondary components shows increasing trends from clean days to polluted days, indicating the importance of secondary aerosol formation processes in driving particulate air pollution. The formation of LO-OOA and MO-OOA is mainly driven by photochemical reactions, but significantly influenced by aqueous-phase chemistry during periods of low atmospheric oxidative capacity.

[Tracing Sources of Sulfate Aerosol in Nanjing Northern Suburb Using Sulfur and Oxygen Isotopes].

PubMed

Wei, Ying; Guo, Zhao-bing; Ge, Xin; Zhu, Sheng-nan; Jiang, Wen-juan; Shi, Lei; Chen, Shu

2015-04-01

Abstract: To trace the sources of sulfate contributing to atmospheric aerosol, PM2.5 samples for isotopic analysis were collected in Nanjing northern suburb during January 2014. The sulfur and oxygen isotopic compositions of sulfate from these samples were determined by EA-IRMS. Source identification and apportionment were carried out using stable isotopic and chemical evidences, combined with absolute principal component analysis (APCA) method. The Δ34S values of aerosol sulfate ranged from 2.7 per thousand to 6.4 per thousand, with an average of 5.0 per thousand ± 0.9 per thousand, while the Δ18O values ranged from 10.6 per thousand to 16.1 per thousand, with an average of 12.5 per thousand ± 1.37 per thousand. In conjunction with air mass trajectories, the results suggested that aerosol sulfates were controlled by a dominance of local anthropogenic sulfate, followed by the contributions of long-distance transported sulfate. There was a minor effect of some other low-Δ34S valued sulfates, which might be expected from biogenic sources. Absolute principal component analysis results showed that the contributions of anthropogenic sulfate and long-distance transported sulfate were 46.74% and 31.54%, respectively.

Source apportionment and dynamic changes of carbonaceous aerosols during the haze bloom-decay process in China based on radiocarbon and organic molecular tracers

NASA Astrophysics Data System (ADS)

Liu, Junwen; Li, Jun; Liu, Di; Ding, Ping; Shen, Chengde; Mo, Yangzhi; Wang, Xinming; Luo, Chunling; Cheng, Zhineng; Szidat, Sönke; Zhang, Yanlin; Chen, Yingjun; Zhang, Gan

2016-03-01

Fine carbonaceous aerosols (CAs) is the key factor influencing the currently filthy air in megacities in China, yet few studies simultaneously focus on the origins of different CAs species using specific and powerful source tracers. Here, we present a detailed source apportionment for various CAs fractions, including organic carbon (OC), water-soluble OC (WSOC), water-insoluble OC (WIOC), elemental carbon (EC) and secondary OC (SOC) in the largest cities of North (Beijing, BJ) and South China (Guangzhou, GZ), using the measurements of radiocarbon and anhydrosugars. Results show that non-fossil fuel sources such as biomass burning and biogenic emission make a significant contribution to the total CAs in Chinese megacities: 56 ± 4 in BJ and 46 ± 5 % in GZ, respectively. The relative contributions of primary fossil carbon from coal and liquid petroleum combustions, primary non-fossil carbon and secondary organic carbon (SOC) to total carbon are 19, 28 and 54 % in BJ, and 40, 15 and 46 % in GZ, respectively. Non-fossil fuel sources account for 52 in BJ and 71 % in GZ of SOC, respectively. These results suggest that biomass burning has a greater influence on regional particulate air pollution in North China than in South China. We observed an unabridged haze bloom-decay process in South China, which illustrates that both primary and secondary matter from fossil sources played a key role in the blooming phase of the pollution episode, while haze phase is predominantly driven by fossil-derived secondary organic matter and nitrate.

Source apportionment and dynamic changes of carbonaceous aerosols during the haze bloom-decay process in China based on radiocarbon and organic molecular tracers

NASA Astrophysics Data System (ADS)

Liu, J.; Li, J.; Liu, D.; Ding, P.; Shen, C.; Mo, Y.; Wang, X.; Luo, C.; Cheng, Z.; Szidat, S.; Zhang, Y.; Chen, Y.; Zhang, G.

2015-12-01

Fine carbonaceous aerosols (CAs) is the key factor influencing the currently filthy air in megacities of China, yet seldom study simultaneously focuses on the origins of different CAs species using specific and powerful source tracers. Here, we present a detailed source apportionment for various CAs fractions, including organic carbon (OC), water-soluble OC (WSOC), water-insoluble OC (WIOC), elemental carbon (EC) and secondary OC (SOC) in the largest cities of North (Beijing, BJ) and South China (Guangzhou, GZ), respectively, using the measurements of radiocarbon and anhydrosugars. Results show that non-fossil fuel sources such as biomass burning and biogenic emission make a significant contribution to the total CAs in Chinese megacities: 56 ± 4 % in BJ and 46 ± 5 % in GZ, respectively. The relative contributions of primary fossil carbon from coal and liquid petroleum combustions, primary non-fossil carbon and secondary organic carbon (SOC) to total carbon are 19, 28 and 54 % in BJ, and 40, 15 and 46 % in GZ, respectively. Non-fossil fuel sources account for 52 % in BJ and 71 % in GZ of SOC, respectively. These results suggest that biomass burning has a greater influence on regional particulate air pollution in North China than in South China. We observed an unabridged haze bloom-decay process in South China, which illustrates that both primary and secondary matter from fossil sources played a key role in the blooming phase of the pollution episode, while haze phase is predominantly driven by fossil-derived secondary organic matter and nitrate.

Source apportionment of size-fractionated particles during the 2013 Asian Youth Games and the 2014 Youth Olympic Games in Nanjing, China.

PubMed

Chen, Pulong; Wang, Tijian; Lu, Xiaobo; Yu, Yiyong; Kasoar, Matthew; Xie, Min; Zhuang, Bingliang

2017-02-01

In this study, samples of size-fractionated particulate matter were collected continuously using a 9-size interval cascade impactor at an urban site in Nanjing, before, during and after the Asian Youth Games (AYG), from July to September of 2013, and the Youth Olympic Games (YOG), from July to September of 2014. First, elemental concentrations, water-soluble ions including Cl - , NO 3 - , SO 4 2- , NH 4 + , K + , Na + and Ca 2+ , organic carbon (OC) and elemental carbon (EC) were analysed. Then, the source apportionment of the fine and coarse particulate matter was carried out using the chemical mass balance (CMB) model. The average PM 10 concentrations were 90.4±20.0μg/m 3 during the 2013 AYG and 70.6±25.3μg/m 3 during the 2014 YOG. For PM 2.1, the average concentrations were 50.0±12.8μg/m 3 in 2013 and 34.6±17.0μg/m 3 in 2014. Investigations showed that the average concentrations of particles declined significantly from 2013 to 2014, and concentrations were at the lowest levels during the events. Results indicated that OC, EC, sulfate and crustal elements have significant monthly and size-based variations. The major components, including crustal elements, water-soluble ions and carbonaceous aerosol accounted for 75.3-91.9% of the total particulate mass concentrations during the sampling periods. Fugitive dust, coal combustion dust, iron dust, construction dust, soil dust, vehicle exhaust, secondary aerosols and sea salt have been classified as the main emissions in Nanjing. The source apportionment results indicate that the emissions from fugitive dust, which was the most abundance emission source during the 2013 AYG, contributed to 23.0% of the total particle mass. However, fugitive dust decreased to 6.2% of the total particle mass during the 2014 YOG. Construction dust (14.7% versus 7.8% for the AYG and the YOG, respectively) and secondary sulfate aerosol (9.3% versus 8.0% for the AYG and the YOG, respectively) showed the same trend as fugitive dust, suggesting that the mitigation measures of controlling particles from the paved roads, construction and industry worked more efficiently during the YOG. Copyright © 2016 Elsevier B.V. All rights reserved.

Primary sources of PM2.5 organic aerosol in an industrial Mediterranean city, Marseille

NASA Astrophysics Data System (ADS)

El Haddad, I.; Marchand, N.; Wortham, H.; Piot, C.; Besombes, J.-L.; Cozic, J.; Chauvel, C.; Armengaud, A.; Robin, D.; Jaffrezo, J.-L.

2011-03-01

Marseille, the most important port of the Mediterranean Sea, represents a challenging case study for source apportionment exercises, combining an active photochemistry and multiple emission sources, including fugitive emissions from industrial sources and shipping. This paper presents a Chemical Mass Balance (CMB) approach based on organic markers and metals to apportion the primary sources of organic aerosol in Marseille, with a special focus on industrial emissions. Overall, the CMB model accounts for the major primary anthropogenic sources including motor vehicles, biomass burning and the aggregate emissions from three industrial processes (heavy fuel oil combustion/shipping, coke production and steel manufacturing) as well as some primary biogenic emissions. This source apportionment exercise is well corroborated by 14C measurements. Primary OC estimated by the CMB accounts on average for 22% of total OC and is dominated by the vehicular emissions that contribute on average for 17% of OC mass concentration (vehicular PM contributes for 17% of PM2.5). Even though industrial emissions contribute only 2.3% of the total OC (7% of PM2.5), they are associated with ultrafine particles (Dp<80 nm) and high concentrations of Polycyclic Aromatic Hydrocarbons (PAH) and heavy metals such as Pb, Ni and V. On one hand, given that industrial emissions governed key primary markers, their omission would lead to substantial uncertainties in the CMB analysis performed in areas heavily impacted by such sources, hindering accurate estimation of non-industrial primary sources and secondary sources. On the other hand, being associated with bursts of submicron particles and carcinogenic and mutagenic components such as PAH, these emissions are most likely related with acute ill-health outcomes and should be regulated despite their small contributions to OC. Another important result is the fact that 78% of OC mass cannot be attributed to the major primary sources and, thus, remains un-apportioned. We have consequently critically investigated the uncertainties underlying our CMB apportionments. While we have provided some evidence for photochemical decay of hopanes, this decay does not appear to significantly alter the CMB estimates of the total primary OC. Sampling artifacts and unaccounted primary sources also appear to marginally influence the amount of un-apportioned OC. Therefore, this significant amount of un-apportioned OC is mostly attributed to secondary organic carbon that appears to be the major component of OC during the whole period of study.

Fossil vs. non-fossil sources of fine carbonaceous aerosols in four Chinese cities during the extreme winter haze episode in 2013

NASA Astrophysics Data System (ADS)

Zhang, Y.-L.; Huang, R.-J.; El Haddad, I.; Ho, K.-F.; Cao, J.-J.; Han, Y.; Zotter, P.; Bozzetti, C.; Daellenbach, K. R.; Canonaco, F.; Slowik, J. G.; Salazar, G.; Schwikowski, M.; Schnelle-Kreis, J.; Abbaszade, G.; Zimmermann, R.; Baltensperger, U.; Prévôt, A. S. H.; Szidat, S.

2014-10-01

During winter 2013, extremely high concentrations (i.e. 4-20 times higher than the World Health Organization guideline) of PM2.5 (particulate matter with an aerodynamic diameter <2.5 μm) were reported in several large cities in China. In this work, source apportionment of fine carbonaceous aerosols during this haze episode was conducted at four major cities in China including Xian, Beijing, Shanghai and Guangzhou. An effective statistical analysis of a combined dataset from elemental carbon (EC) and organic carbon (OC), radiocarbon (14C) and biomass-burning marker measurements using Latin-hypercube sampling allowed a quantitative source apportionment of carbonaceous aerosols. We found that fossil emissions from coal combustion and vehicle exhaust dominated EC with a mean contribution of 75 ± 8% at all sites. The remaining 25 ± 8% was exclusively attributed to biomass combustion, consistent with the measurements of biomass-burning markers such as anhydrosugars (levoglucosan and mannosan) and water-soluble potassium (K+). With a combination of the levoglucosan-to-mannosan and levoglucosan-to-K+ ratios, the major source of biomass burning in winter in China is suggested to be combustion of crop residues. The contribution of fossil sources to OC was highest in Beijing (58 ± 5%) and decreased from Shanghai (49 ± 2%) to Xian (38 ± 3%) and Guangzhou (35 ± 7%). Generally, a larger fraction of fossil OC was rather from secondary origins than primary sources for all sites. Non-fossil sources accounted on average for 55 ± 10% and 48 ± 9% of OC and TC, respectively, which suggests that non-fossil emissions were very important contributors of urban carbonaceous aerosols in China. The primary biomass-burning emissions accounted for 40 ± 8%, 48 ± 18%, 53 ± 4% and 65 ± 26% of non-fossil OC for Xian, Beijing, Shanghai and Guangzhou, respectively. Other non-fossil sources excluding primary biomass-burning were mainly attributed to formation of secondary organic carbon (SOC) from non-fossil precursors such as biomass-burning emissions. For each site, we also compared samples from moderately with heavily polluted days according to particulate matter mass. Despite a significant increase of absolute mass concentrations of primary emissions from both, fossil and non-fossil sources, during the heavily polluted events, their relative contribution to TC was even decreased, whereas the portion of SOC was consistently increased at all sites. This observation indicates that SOC was an important fraction in the increment of carbonaceous aerosols during the haze episode in China.

Mass closure and source apportionment of PM2.5 by Positive Matrix Factorization analysis in urban Mediterranean environment

NASA Astrophysics Data System (ADS)

Mantas, E.; Remoundaki, E.; Halari, I.; Kassomenos, P.; Theodosi, C.; Hatzikioseyian, A.; Mihalopoulos, N.

2014-09-01

A systematic monitoring of PM2.5 was carried out during a period of three years (from February 2010 to April 2013) at an urban site, at the National Technical University of Athens campus. Two types of 24-h PM2.5 samples have been collected: 271 samples on PTFE and 116 samples on quartz filters. Daily PM2.5 concentrations were determined for both types of samples. Total sulfur, crustal origin elements and elements of a major crustal component (Al, Si, Fe, Ca, K, Mg, Ti) trace elements (Zn, Pb, Cu, Ni, P, V, Cr, Mn) and water soluble ions (Cl-, NO3-, SO42-, Na+, K+, NH4+, Ca2+, Mg2+) were determined on the PTFE samples. Organic carbon (OC), elemental carbon (EC) and water soluble ions were determined on the quartz samples. For the mass closure six components were considered: Secondary Inorganic Aerosol (SIA), Organic Matter (OM), Elemental Carbon (EC), Dust, Mineral anthropogenic component (MIN) and Sea Salt (SS). SIA and OM contributed in the mass of PM2.5 almost equally: 30-36% and 30% respectively. EC, SS and MIN accounted for 5, 4 and 3% respectively of the total PM2.5 mass. Dust accounted for about 3-5% in absence of dust transport event and reached a much higher percentage in case of dust transport event. These contributions justify at least 80% of the PM2.5 mass. Source apportionment analysis has been performed by Positive Matrix Factorization. The combination of the PMF results obtained by both data sets lead to the definition of six factors: 1. SO42-, NH4+, OC (industrial/regional sources, secondary aerosol) 2. EC, OC, K and trace metals (traffic and heating by biomass burning, locally emitted aerosol). 3. Ca, EC, OC and trace metals (urban-resuspended road dust reflecting exhaust emissions), 4. Secondary nitrates 5. Na, Cl (marine source) 6. Si, Al, Ti, Ca, Fe (Dust transported from Sahara). These factors reflect not only main sources contributions but also underline the key role of atmospheric dynamics and aerosol ageing processes in this Mediterranean environment.

Data Assimilation to Improve CMAQ Model Estimates of Particulate Matter Pollution during Wintertime Persistent Cold Air Pool Events in Salt Lake City, Utah

NASA Astrophysics Data System (ADS)

Ivey, C. E.; Balachandran, S.; Russell, A. G.; Hu, Y.; Holmes, H.

2017-12-01

More than one million people live in Salt Lake Valley, Utah, where wintertime pollution reaches unhealthy levels due to the unique meteorology and orography of the region. Persistent cold air pool (PCAP) events occur when high pressure ridges create stagnant conditions over a valley, which hampers large-scale advection and reduces surface wind speeds. During PCAP periods the fraction of incoming solar radiation that reaches the valley floor is also reduced, leading to temperature inversions that allow pollution to build. Pollution levels continue to climb until a washout event removes the pollutants from the valley. Washout events include high winds or precipitation events with advection or wet deposition related removal processes, respectively. In this work, novel data assimilation and source apportionment techniques are applied for January and February 2007 to analyze CMAQ-modeled source composition and source impacts for the Salt Lake Valley during PCAP events. First, a hybrid source-oriented apportionment model is applied over continental U.S. to determine observation and model-based impacts from 20 sources, including agricultural activities, fossil fuel combustion, dust, and metals processing. Then, a secondary bias correction method is applied to better quantify the source impacts on secondary PM2.5, which constitutes the majority of the PM2.5 mass. Revised concentrations reflect what was previously reported in studies of PCAP pollution in the Salt Lake Valley, where the dominant aerosol was found to be ammonium nitrate. Further, gasoline and natural gas combustion were found to be the greatest contributing sources to aerosol concentrations during the PCAP events. The benefit of the data assimilation methods is the availability of spatially and temporally resolved model estimates of source impacts that better reflect observed concentrations.

Stoichiometry of water-soluble ions in PM2.5: Application in source apportionment for a typical industrial city in semi-arid region, Northwest China

NASA Astrophysics Data System (ADS)

Zhou, Haijun; Lü, Changwei; He, Jiang; Gao, Manshu; Zhao, Boyi; Ren, Limin; Zhang, Lijun; Fan, Qingyun; Liu, Tao; He, Zhongxiang; Dudagula; Zhou, Bin; Liu, Hualin; Zhang, Yu

2018-05-01

Water-soluble ions (WSIs) are major components of PM2.5 and it is valuable for understanding physical and chemical characteristics, sources, behaviors and formation mechanism of WSIs. Baotou is a traditionally industrial city in semi-arid region and frequently subjected to dust storms from March to May. In recent years, air pollution has been listed as one of the most important environmental problems in Baotou. To investigate the seasonal variations and sources of WSIs in PM2.5, the WSIs including SO42-, NO3-, Cl-, F-, NH4+, K+, Na+, Ca2+ and Mg2+ were monitored at six urban sites in Baotou. The results showed that high concentrations of Ca2+ and Na+ were found responding to dust storm events, while high concentrations of SO42-, NO3-, NH4+, K+ and Cl- were observed during haze days. The correlations analysis indicated that excess sulfuric and nitric acid was likely neutralized by carbonate minerals such as calcite, aragonite and dolomite in normal days and cations were fully neutralized during all the sampling periods, while cations were excessive in dust storm days. The concentrations of [NH4+ + SO42- + NO3-], [Na+ + Ca2+ + Mg2+] and [Cl- + K+ + F-] indicated the northwest and southeast region of Baotou presented comparatively high contributions of secondary aerosol and crustal dust, respectively, which were mainly related to the industrial distribution and urbanization process. The cluster analysis, ternary diagram and principal component analysis have a good agreement in source apportionment, where crustal dust sources, secondary aerosol source and the mixture of coal combustion, biomass burning and industrial pollution sources were the main sources of WSIs in PM2.5. The seasonal pattern of sulfur oxidation ratio (SOR) was September > April > November > January, while the nitrogen oxidation ratio (NOR) April > January > November > September in Baotou. This work evaluated the seasonal variation, distribution and source of WSIs on the basis of its stoichiometry in PM2.5, which help to explore the potential sources of these inorganic aerosols and provide scientific suggestion for air quality improvement in Baotou.

Source Apportionment Using Positive Matrix Factorization on Daily Measurements of Inorganic and Organic Speciated PM2.5

PubMed Central

Dutton, Steven J.; Vedal, Sverre; Piedrahita, Ricardo; Milford, Jana B.; Miller, Shelly L.; Hannigan, Michael P.

2012-01-01

Particulate matter less than 2.5 microns in diameter (PM2.5) has been linked with a wide range of adverse health effects. Determination of the sources of PM2.5 most responsible for these health effects could lead to improved understanding of the mechanisms of such effects and more targeted regulation. This has provided the impetus for the Denver Aerosol Sources and Health (DASH) study, a multi-year source apportionment and health effects study relying on detailed inorganic and organic PM2.5 speciation measurements. In this study, PM2.5 source apportionment is performed by coupling positive matrix factorization (PMF) with daily speciated PM2.5 measurements including inorganic ions, elemental carbon (EC) and organic carbon (OC), and organic molecular markers. A qualitative comparison is made between two models, PMF2 and ME2, commonly used for solving the PMF problem. Many previous studies have incorporated chemical mass balance (CMB) for organic molecular marker source apportionment on limited data sets, but the DASH data set is large enough to use multivariate factor analysis techniques such as PMF. Sensitivity of the PMF2 and ME2 models to the selection of speciated PM2.5 components and model input parameters was investigated in depth. A combination of diagnostics was used to select an optimum, 7-factor model using one complete year of daily data with pointwise measurement uncertainties. The factors included 1) a wintertime/methoxyphenol factor, 2) an EC/sterane factor, 3) a nitrate/polycyclic aromatic hydrocarbon (PAH) factor, 4) a summertime/selective aliphatic factor, 5) an n-alkane factor, 6) a middle oxygenated PAH/alkanoic acid factor and 7) an inorganic ion factor. These seven factors were qualitatively linked with known PM2.5 emission sources with varying degrees of confidence. Mass apportionment using the 7-factor model revealed the contribution of each factor to the mass of OC, EC, nitrate and sulfate. On an annual basis, the majority of OC and EC mass was associated with the summertime/selective aliphatic factor and the EC/sterane factor, respectively, while nitrate and sulfate mass were both dominated by the inorganic ion factor. This apportionment was found to vary substantially by season. Several of the factors identified in this study agree well with similar assessments conducted in St. Louis, MO and Pittsburgh, PA using PMF and organic molecular markers. PMID:22768005

[Application of ICP-MS and ICP-AES for Studying on Source Apportionment of PM2.5 during Haze Weather in Urban Beijing].

PubMed

Chen, Xi; Du, Peng; Guan, Qing; Feng, Xu; Xu, Dong-qun; Lin, Shao-bin

2015-06-01

To investigate the characteristics of chemical constitute and pollution sources of aerosol fine particulate matter during haze-fog day in Beijing in winter 2013. The samples of PM2.5 were collected in Beijing from January to February, 2013. The technique of ICP-MS and ICP-AES coupled with procedure of bathing-ultrasonic extraction was applied to determine the concentration of 40 elements in the aerosol samples to analyze the characteristics of elements distribution statistically. The absolute principal factor method was used to apportion the pollution sources of PM2.5 during the haze weather in Beijing city in winter 2013. The results showed that during the period of sampling, the volume concentration of Li, Mn, Pb, S etc. obeyed normal distribution approximately, and according to National Ambient Air Quality Standard issued by Ministry of Environmental Protection of the People's Republic of China, the geometric mean concentration of As was twice the annual limit of standard reference, while Pb of some aerosol samples beyond the annual limit of standard reference respectively. The mass fraction of Fe, Zn, Pb, Ti accounted for over 0.1%, while that of Mn, Cu, As, Se etc. 0.01%. These elements were primary inorganic pollutants, and especially the hazards and sources of As and Pb should be concerned. There were 6 main pollution sources were chosen by the factor analysis method, including industrial dust and human beings activities, biomass combustion and building dust, soil and sand dusts, fossil fuel, electronic waste and metal smelting, with the variance contribution rate of 40.3%, 27.0%, 9.1%, 4.9%, 4.8% and 4.6% respectively. ICP-MS and ICP-AES can be applied to analyzing multi-elements in PM2.5 accurately and quickly to facilitate source apportionment, and it indicated that the relevant pollution sources should be considered and the effect of regional transferring of haze pollution sources should be taken into account, and specific measures should be taken for control.

Influence of continental organic aerosols to the marine atmosphere over the East China Sea: Insights from lipids, PAHs and phthalates.

PubMed

Kang, Mingjie; Yang, Fan; Ren, Hong; Zhao, Wanyu; Zhao, Ye; Li, Linjie; Yan, Yu; Zhang, Yingjie; Lai, Senchao; Zhang, Yingyi; Yang, Yang; Wang, Zifa; Sun, Yele; Fu, Pingqing

2017-12-31

Total suspended particle (TSP) samples were collected during a marine cruise in the East China Sea from May 18 to June 12, 2014. They were analyzed for solvent extractable organic compounds (lipid compounds, PAHs and phthalates) using gas chromatography/mass spectrometry (GC/MS) to better understand the sources and source apportionment of aerosol pollution in the western North Pacific. Higher concentrations were observed in the terrestrially influenced aerosol samples on the basis of five-day backward air mass trajectories, especially for aerosols collected near coastal areas. Phthalates were found to be the dominant species among these measured compound classes (707±401ngm -3 for daytime and 313±155ngm -3 for nighttime), followed by fatty acids, fatty alcohols, n-alkanes and PAHs. In general, the daytime abundances for these compounds are higher than nighttime, possibly attributable to more intensive anthropogenic activities during the daytime. The factor analysis indicates that biomass burning, fungal activities and fossil fuel combustion maybe the main emission sources for organic aerosols over the East China Sea. This study demonstrates that the East Asian continent can be a natural emitter of biogenic and anthropogenic organics to the marine atmosphere through long-range transport, which controls the chemical composition and concentration of organic aerosols over the East China Sea. Copyright © 2017 Elsevier B.V. All rights reserved.

Source apportionment of organic compounds in Berlin using positive matrix factorization - assessing the impact of biogenic aerosol and biomass burning on urban particulate matter.

PubMed

Wagener, Sandra; Langner, Marcel; Hansen, Ute; Moriske, Heinz-Jörn; Endlicher, Wilfried R

2012-10-01

Source apportionment of 13 organic compounds, elemental carbon and organic carbon of ambient PM(10) and PM(1) was performed with positive matrix factorization (PMF). Samples were collected at three sites characterized by different vegetation influences in Berlin, Germany in 2010. The aim was to determine organic, mainly biogenic sources and their impact on urban aerosol collected in a densely populated region. A 6-factor solution provided the best data fit for both PM-fractions, allowing the sources isoprene- and α-pinene-derived secondary organic aerosol (SOA), bio primary, primarily attributable to fungal spores, bio/urban primary including plant fragments in PM(10) and cooking and traffic emissions in PM(1), biomass burning and combustion fossil to be identified. With mean concentrations up to 2.6 μg Cm(-3), biomass burning dominated the organic fraction in cooler months. Concentrations for α-pinene-derived SOA exceeded isoprene-derived concentrations. Estimated secondary organic carbon contributions to total organic carbon (OC) were between 7% and 42% in PM(10) and between 11% and 60% in PM(1), which is slightly lower than observed for US- or Asian cities. Primary biogenic emissions reached up to 33% of OC in the PM(10)-fraction in the late summer and autumn months. Temperature-dependence was found for both SOA-factors, correlations with ozone and mix depth only for the α-pinene-derived SOA-factor. Latter indicated input of α-pinene from the borders, highlighting differences in the origin of the precursors of both factors. Most factors were regionally distributed. High regional distribution was found to be associated with stronger influence of ambient parameters and higher concentrations at the background station. A significant contribution of biogenic emissions and biomass burning to urban organic aerosol could be stated. This indicates a considerable impact on PM concentrations also in cities in a densely populated area, and should draw the attention concerning health aspects not only to cardio-vascular diseases but also to allergy issues. Copyright © 2012 Elsevier B.V. All rights reserved.

Fine mode aerosol chemistry over a rural atmosphere near the north-east coast of Bay of Bengal in India

NASA Astrophysics Data System (ADS)

Adak, Anandamay; Chatterjee, Abhijit; Ghosh, Sanjay; Raha, Sibaji; Roy, Arindam

2016-07-01

A study was conducted on the chemical characterization of fine mode aerosol or PM2.5 over a rural atmosphere near the coast of Bay of Bengal in eastern India. Samples were collected and analyzed during March 2013 - February 2014. The concentration of PM2.5 was found span over a wide range from as low as 3 µg m-3 to as high as 180 µg m-3. The average concentration of PM2.5 was 62 µg m-3. Maximum accumulation of fine mode aerosol was observed during winter whereas minimum was observed during monsoon. Water soluble ionic species of fine mode aerosol were characterized over this rural atmosphere. In spite of being situated near the coast of Bay of Bengal, we observed significantly higher concentrations for anthropogenic species like ammonium and sulphate. The concentrations of these two species were much higher than the sea-salt aerosols. Ammonium and sulphate contributed around 30 % to the total fine mode aerosols. Even dust aerosol species like calcium also showed higher concentrations. Chloride to sodium ratio was found to be much less than that in standard sea-water indicating strong interaction between sea-salt and anthropogenic aerosols. Use of fertilizers in various crop fields and human and animal wastes significantly increased ammonium in fine mode aerosols. Dust aerosol species were accumulated in the atmosphere which could be due to transport of finer dust species from nearby metropolis or locally generated. Non-sea-sulphate and nitrate showed significant contributions in fine mode aerosols having both local and transported sources. Source apportionment shows prominent emission sources of anthropogenic aerosols from local anthropogenic activities and transported from nearby Kolkata metropolis as well.

Source apportionment of major and trace elements in aerosols during smog episodes in large cities in China

NASA Astrophysics Data System (ADS)

Furger, Markus; Rai, Pragati; Visser, Suzanne; Elser, Miriam; Canonaco, Francesco; Slowik, Jay G.; Huang, Ru-Jin; Prévôt, André S. H.; Baltensperger, Urs

2017-04-01

Air pollution in Chinese cities is one of the environmental problems China has to address to mitigate the impacts on human health, air quality and climate. Average concentrations of particulate matter exceed 100 μg m-3 in many places in China, and the government is developing and implementing strategies to reduce the load of pollutants by various measures. A characterization of airborne particulate matter (PM), especially its composition and sources, will help in optimizing reduction and mitigation strategies for air pollution. We collected PM10 aerosols with a rotating drum impactor (RDI) in Xi'an in December 2013 and in Beijing in January 2014 with 30-min time resolution and for three size ranges (cut-off sizes 10, 2.5 and 1 μm). Each campaign encompassed one or more high pollution episodes in the respective city. Elements from Na to Pb were analyzed with synchrotron radiation induced X-ray fluorescence spectrometry (SR-XRF), and the resulting time series were used for source apportionment performed with the Multilinear-Engine 2 (ME-2) implementation of the Positive Matrix Factorization algorithm. The preliminary computations yielded 5 factors for Beijing, namely road dust, sea salt, traffic-related, industrial, coal combustion. For Xi'an an additional desert dust factor was found. Further refinement could be expected from including the smaller size fractions, e.g. a sulfur-rich factor for secondary sulfate or a reacted chlorine factor in the fine mode fraction.

Source apportionment of submicron organic aerosol collected from Atlanta, Georgia, during 2014-2015 using the aerosol chemical speciation monitor (ACSM)

NASA Astrophysics Data System (ADS)

Rattanavaraha, Weruka; Canagaratna, Manjula R.; Budisulistiorini, Sri Hapsari; Croteau, Philip L.; Baumann, Karsten; Canonaco, Francesco; Prevot, Andre S. H.; Edgerton, Eric S.; Zhang, Zhenfa; Jayne, John T.; Worsnop, Douglas R.; Gold, Avram; Shaw, Stephanie L.; Surratt, Jason D.

2017-10-01

The Aerodyne Aerosol Chemical Speciation Monitor (ACSM) was redeployed at the Jefferson Street (JST) site in downtown Atlanta, Georgia (GA) for 1 year (March 20, 2014-February 08, 2015) to chemically characterize non-refractory submicron particulate matter (NR-PM1) in near real-time and to assess whether organic aerosol (OA) types and amounts change from year-to-year. Submicron organic aerosol (OA) mass spectra were analyzed by season using multilinear engine (ME-2) to apportion OA subtypes to potential sources and chemical processes. A suite of real-time collocated measurements from the Southeastern Aerosol Research and Characterization (SEARCH) network was compared with ME-2 factor solutions to aid in the interpretation of OA subtypes during each season. OA tracers measured from high-volume filter samples using gas chromatography interfaced with electron ionization-mass spectrometry (GC/EI-MS) also aided in identifying OA sources. The initial application of ME-2 to the yearlong ACSM dataset revealed that OA source apportionment by season was required to better resolve sporadic OA types. Spring and fall OA mass spectral datasets were separated into finer periods to capture potential OA sources resulting from non-homogeneous emissions during transitioning periods. NR-PM1 was highest in summer (16.7 ± 8.4 μg m-3) and lowest in winter (8.0 ± 5.7 μg m-3), consistent with prior studies. OA dominated NR-PM1 mass (56-74% on average) in all seasons. Hydrocarbon-like OA (HOA) from primary emissions was observed in all seasons, averaging 5-22% of total OA mass. Strong correlations of HOA with carbon monoxide (CO) (R = 0.71-0.88) and oxides of nitrogen (NOx) (R = 0.55-0.79) indicated that vehicular traffic was the likely source. Biomass burning OA (BBOA) was observed in all seasons, with lower contributions (2%) in summer and higher in colder seasons (averaging 8-20% of total OA mass). BBOA correlated strongly with levoglucosan (R = 0.78-0.95) during colder seasons, which supports that BBOA is likely derived from fresh biomass/residential burning. However, weaker correlation with levoglucosan (R = 0.38) in summer suggested a more aged aerosol. During warmer seasons, OA from the reactive uptake of isoprene epoxydiols (IEPOX) onto acidic sulfate aerosol was resolved by ME-2 (denoted as IEPOX-OA), averaging 25-29% of the total OA mass. Temporal variation of IEPOX-OA was nearly coincident with that of 91Fac OA (a factor dominated by a distinct ion at m/z 91). The largest contribution of IEPOX-OA to total OA (29%) was found in summer, whereas the largest contribution of 91Fac to total OA (24%) occurred in early fall. Moderate negative correlation between IEPOX-OA and aerosol acidity was observed during late spring (-0.67) and summer (-0.42), consistent with laboratory studies showing that IEPOX-OA is enhanced in the presence of acidic aerosols. Finally, the largest OA mass in all seasons (46-70% of total OA) was derived from oxygenated OA denoted as low-volatility oxygenated OA (LV-OOA) and semi-volatile oxygenated OA (SV-OOA).

Sources of atmospheric aerosol from long-term measurements (5 years) of chemical composition in Athens, Greece.

PubMed

Paraskevopoulou, D; Liakakou, E; Gerasopoulos, E; Mihalopoulos, N

2015-09-15

To identify the sources of aerosols in Greater Athens Area (GAA), a total of 1510 daily samples of fine (PM 2.5) and coarse (PM 10-2,5) aerosols were collected at a suburban site (Penteli), during a five year period (May 2008-April 2013) corresponding to the period before and during the financial crisis. In addition, aerosol sampling was also conducted in parallel at an urban site (Thissio), during specific, short-term campaigns during all seasons. In all these samples mass and chemical composition measurements were performed, the latest only at the fine fraction. Particulate organic matter (POM) and ionic masses (IM) are the main contributors of aerosol mass, equally contributing by accounting for about 24% of the fine aerosol mass. In the IM, nss-SO4(-2) is the prevailing specie followed by NO3(-) and NH4(+) and shows a decreasing trend during the 2008-2013 period similar to that observed for PM masses. The contribution of water in fine aerosol is equally significant (21 ± 2%), while during dust transport, the contribution of dust increases from 7 ± 2% to 31 ± 9%. Source apportionment (PCA and PMF) and mass closure exercises identified the presence of six sources of fine aerosols: secondary photochemistry, primary combustion, soil, biomass burning, sea salt and traffic. Finally, from winter 2012 to winter 2013 the contribution of POM to the urban aerosol mass is increased by almost 30%, reflecting the impact of wood combustion (dominant fuel for domestic heating) to air quality in Athens, which massively started in winter 2013. Copyright © 2015 Elsevier B.V. All rights reserved.

Improving source identification of Atlanta aerosol using temperature resolved carbon fractions in positive matrix factorization

NASA Astrophysics Data System (ADS)

Kim, Eugene; Hopke, Philip K.; Edgerton, Eric S.

Daily integrated PM 2.5 (particulate matter ⩽2.5 μm in aerodynamic diameter) composition data including eight individual carbon fractions collected at the Jefferson Street monitoring site in Atlanta were analyzed with positive matrix factorization (PMF). Particulate carbon was analyzed using the thermal optical reflectance method that divides carbon into four organic carbon (OC), pyrolized organic carbon (OP), and three elemental carbon (EC) fractions. A total of 529 samples and 28 variables were measured between August 1998 and August 2000. PMF identified 11 sources in this study: sulfate-rich secondary aerosol I (50%), on-road diesel emissions (11%), nitrate-rich secondary aerosol (9%), wood smoke (7%), gasoline vehicle (6%), sulfate-rich secondary aerosol II (6%), metal processing (3%), airborne soil (3%), railroad traffic (3%), cement kiln/carbon-rich (2%), and bus maintenance facility/highway traffic (2%). Differences from previous studies using only the traditional OC and EC data (J. Air Waste Manag. Assoc. 53(2003a)731; Atmos Environ. (2003b)) include four traffic-related combustion sources (gasoline vehicle, on-road diesel, railroad, and bus maintenance facility) containing carbon fractions whose abundances were different between the various sources. This study indicates that the temperature resolved fractional carbon data can be utilized to enhance source apportionment study, especially with respect to the separation of diesel emissions from gasoline vehicle sources. Conditional probability functions using surface wind data and identified source contributions aid the identifications of local point sources.

Primary sources of PM2.5 organic aerosol in an industrial Mediterranean city, Marseille

NASA Astrophysics Data System (ADS)

El Haddad, I.; Marchand, N.; Wortham, H.; Piot, C.; Besombes, J.-L.; Cozic, J.; Chauvel, C.; Armengaud, A.; Robin, D.; Jaffrezo, J.-L.

2010-11-01

Marseille, the most important port of the Mediterranean Sea, represents a challenging case study for source apportionment exercises, combining an active photochemistry and multiple emission sources, including fugitive emissions from industrial sources and shipping. This paper presents a Chemical Mass Balance (CMB) approach based on organic markers and metals to apportion the primary sources of organic aerosol in Marseille, with a special focus on industrial emissions. Overall, the CMB model accounts for the major primary anthropogenic sources including motor vehicles, biomass burning, and the aggregate emissions from three industrial processes (HFO combustion/shipping, coke production and steel manufacturing) as well as some primary biogenic emissions. This source apportionment exercise is well corroborated by 14C measurements. Primary OC estimated by the CMB accounts on average for 22% and is dominated by the vehicular emissions that contribute on average for 17% of OC mass concentration (17% of PM2.5). Even though, industrial emissions contribute for only 2.3% of the total OC (7% of PM2.5), they are associated with ultrafine particles (Dp<80 nm) and high concentrations of Polycyclic Aromatic Hydrocarbons (PAH) and heavy metals such as Pb, Ni and V. On one hand, given that industrial emissions governed key primary markers, their omission would lead to substantial uncertainties in the CMB analysis performed in areas heavily impacted by such sources, hindering accurate estimation of non-industrial primary sources and secondary sources. This result implies that CMB modelling should not be a straightforward exercise and one have to carefully investigate the marker behaviours and trends beforehand, especially in complex environments such as Marseille. On the other hand, being associated with bursts of submicron particles and carcinogenic and mutagenic components such as PAH, these emissions are most likely related with acute health outcomes and should be regulated despite their small contributions to OC. Another important result is the fact that 78% of OC mass cannot be attributed to the major primary sources and thus remains un-apportioned. We have consequently critically investigated the uncertainties underlying our CMB apportionments. While we have provided some evidence for photochemical decay of hopanes, this decay does not appear to significantly alter the CMB estimates of the total primary OC. Sampling artefacts and unaccounted primary sources also appear to marginally influence the amount of un-apportioned OC. Therefore, this significant amount of un-apportioned OC is mostly attributed to secondary organic carbon that appears to be the major component of OC, during the whole period of study.

Apportionment of urban aerosol sources in Cork (Ireland) by synergistic measurement techniques.

PubMed

Dall'Osto, Manuel; Hellebust, Stig; Healy, Robert M; O'Connor, Ian P; Kourtchev, Ivan; Sodeau, John R; Ovadnevaite, Jurgita; Ceburnis, Darius; O'Dowd, Colin D; Wenger, John C

2014-09-15

The sources of ambient fine particulate matter (PM2.5) during wintertime at a background urban location in Cork city (Ireland) have been determined. Aerosol chemical analyses were performed by multiple techniques including on-line high resolution aerosol time-of-flight mass spectrometry (Aerodyne HR-ToF-AMS), on-line single particle aerosol time-of-flight mass spectrometry (TSI ATOFMS), on-line elemental carbon-organic carbon analysis (Sunset_EC-OC), and off-line gas chromatography/mass spectrometry and ion chromatography analysis of filter samples collected at 6-h resolution. Positive matrix factorization (PMF) has been carried out to better elucidate aerosol sources not clearly identified when analyzing results from individual aerosol techniques on their own. Two datasets have been considered: on-line measurements averaged over 2-h periods, and both on-line and off-line measurements averaged over 6-h periods. Five aerosol sources were identified by PMF in both datasets, with excellent agreement between the two solutions: (1) regional domestic solid fuel burning--"DSF_Regional," 24-27%; (2) local urban domestic solid fuel burning--"DSF_Urban," 22-23%; (3) road vehicle emissions--"Traffic," 15-20%; (4) secondary aerosols from regional anthropogenic sources--"SA_Regional" 9-13%; and (5) secondary aged/processed aerosols related to urban anthropogenic sources--"SA_Urban," 21-26%. The results indicate that, despite regulations for restricting the use of smoky fuels, solid fuel burning is the major source (46-50%) of PM2.5 in wintertime in Cork, and also likely other areas of Ireland. Whilst wood combustion is strongly associated with OC and EC, it was found that peat and coal combustion is linked mainly with OC and the aerosol from these latter sources appears to be more volatile than that produced by wood combustion. Ship emissions from the nearby port were found to be mixed with the SA_Regional factor. The PMF analysis allowed us to link the AMS cooking organic aerosol factor (AMS_PMF_COA) to oxidized organic aerosol, chloride and locally produced nitrate, indicating that AMS_PMF_COA cannot be attributed to primary cooking emissions only. Overall, there are clear benefits from factor analysis applied to results obtained from multiple techniques, which allows better association of aerosols with sources and atmospheric processes. Copyright © 2014 Elsevier B.V. All rights reserved.

PM10 source apportionment applying PMF and chemical tracer analysis to ship-borne measurements in the Western Mediterranean

NASA Astrophysics Data System (ADS)

Bove, M. C.; Brotto, P.; Calzolai, G.; Cassola, F.; Cavalli, F.; Fermo, P.; Hjorth, J.; Massabò, D.; Nava, S.; Piazzalunga, A.; Schembari, C.; Prati, P.

2016-01-01

A PM10 sampling campaign was carried out on board the cruise ship Costa Concordia during three weeks in summer 2011. The ship route was Civitavecchia-Savona-Barcelona-Palma de Mallorca-Malta (Valletta)-Palermo-Civitavecchia. The PM10 composition was measured and utilized to identify and characterize the main PM10 sources along the ship route through receptor modelling, making use of the Positive Matrix Factorization (PMF) algorithm. A particular attention was given to the emissions related to heavy fuel oil combustion by ships, which is known to be also an important source of secondary sulphate aerosol. Five aerosol sources were resolved by the PMF analysis. The primary contribution of ship emissions to PM10 turned out to be (12 ± 4)%, while secondary ammonium sulphate contributed by (35 ± 5)%. Approximately, 60% of the total sulphate was identified as secondary aerosol while about 20% was attributed to heavy oil combustion in ship engines. The measured concentrations of methanesulphonic acid (MSA) indicated a relevant contribution to the observed sulphate loading by biogenic sulphate, formed by the atmospheric oxidation of dimethyl sulphide (DMS) emitted by marine phytoplankton.

Identification and characterization of fine and coarse particulate matter sources in a middle-European urban environment

NASA Astrophysics Data System (ADS)

Kertész, Zs.; Szoboszlai, Z.; Angyal, A.; Dobos, E.; Borbély-Kiss, I.

2010-06-01

In this work a source apportionment study is presented which aimed to characterize the PM 2.5 and PM 2.5-10 sources in the urban area of Debrecen, East-Hungary by using streaker samples, IBA methods and positive matrix factorization (PMF) analysis. Samples of fine (PM 2.5) and coarse (PM 2.5-10) urban particulate matter were collected with 2 h time resolution in the frame of five sampling campaigns during 2007-2009 in different seasons in the downtown of Debrecen. Elemental concentrations from Al to Pb of over 1000 samples were obtained by particle induced X-ray emission (PIXE); concentrations of black carbon (BC) were determined with a smoke stain reflectometer. On this data base source apportionment was carried out by using the PMF method. Seven factors were identified for both size fractions, including soil dust, traffic, secondary aerosol - sulphates, domestic heating, oil combustion, agriculture and an unknown factor enriched with chlorine. Seasonal and daily variation of the different factors was studied as well as their dependence on meteorological parameters. Besides determining the time patterns characteristic to the city, several emission episodes were identified including a Saharan dust intrusion on 21st-24th May, 2008.

The Denver Aerosol Sources and Health (DASH) Study: Overview and Early Findings

PubMed Central

Vedal, S.; Hannigan, M.P.; Dutton, S.J.; Miller, S. L.; Milford, J.B.; Rabinovitch, N.; Kim, S.-Y.; Sheppard, L.

2012-01-01

Improved understanding of the sources of air pollution that are most harmful could aid in developing more effective measures for protecting human health. The Denver Aerosol Sources and Health (DASH) study was designed to identify the sources of ambient fine particulate matter (PM2.5) that are most responsible for the adverse health effects of short-term exposure to PM 2.5. Daily 24-hour PM2.5 sampling began in July 2002 at a residential monitoring site in Denver, Colorado, using both Teflon and quartz filter samplers. Sampling is planned to continue through 2008. Chemical speciation is being carried out for mass, inorganic ionic compounds (sulfate, nitrate and ammonium), and carbonaceous components, including elemental carbon, organic carbon, temperature-resolved organic carbon fractions and a large array of organic compounds. In addition, water soluble metals were measured daily for 12 months in 2003. A receptor-based source apportionment approach utilizing positive matrix factorization (PMF) will be used to identify PM 2.5 source contributions for each 24-hour period. Based on a preliminary assessment using synthetic data, the proposed source apportionment should be able to identify many important sources on a daily basis, including secondary ammonium nitrate and ammonium sulfate, diesel vehicle exhaust, road dust, wood combustion and vegetative debris. Meat cooking, gasoline vehicle exhaust and natural gas combustion were more challenging for PMF to accurately identify due to high detection limits for certain organic molecular marker compounds. Measurements of these compounds are being improved and supplemented with additional organic molecular marker compounds. The health study will investigate associations between daily source contributions and an array of health endpoints, including daily mortality and hospitalizations and measures of asthma control in asthmatic children. Findings from the DASH study, in addition to being of interest to policymakers, by identifying harmful PM2.5 sources may provide insights into mechanisms of PM effect. PMID:22723735

The Denver Aerosol Sources and Health (DASH) study: Overview and early findings

NASA Astrophysics Data System (ADS)

Vedal, S.; Hannigan, M. P.; Dutton, S. J.; Miller, S. L.; Milford, J. B.; Rabinovitch, N.; Kim, S.-Y.; Sheppard, L.

Improved understanding of the sources of air pollution that are most harmful could aid in developing more effective measures for protecting human health. The Denver Aerosol Sources and Health (DASH) study was designed to identify the sources of ambient fine particulate matter (PM 2.5) that are most responsible for the adverse health effects of short-term exposure to PM 2.5. Daily 24-h PM 2.5 sampling began in July 2002 at a residential monitoring site in Denver, Colorado, using both Teflon and quartz filter samplers. Sampling is planned to continue through 2008. Chemical speciation is being carried out for mass, inorganic ionic compounds (sulfate, nitrate and ammonium), and carbonaceous components, including elemental carbon, organic carbon, temperature-resolved organic carbon fractions and a large array of organic compounds. In addition, water-soluble metals were measured daily for 12 months in 2003. A receptor-based source apportionment approach utilizing positive matrix factorization (PMF) will be used to identify PM 2.5 source contributions for each 24-h period. Based on a preliminary assessment using synthetic data, the proposed source apportionment should be able to identify many important sources on a daily basis, including secondary ammonium nitrate and ammonium sulfate, diesel vehicle exhaust, road dust, wood combustion and vegetative debris. Meat cooking, gasoline vehicle exhaust and natural gas combustion were more challenging for PMF to accurately identify due to high detection limits for certain organic molecular marker compounds. Measurements of these compounds are being improved and supplemented with additional organic molecular marker compounds. The health study will investigate associations between daily source contributions and an array of health endpoints, including daily mortality and hospitalizations and measures of asthma control in asthmatic children. Findings from the DASH study, in addition to being of interest to policymakers, by identifying harmful PM 2.5 sources may provide insights into mechanisms of PM effect.

Urban PM in Eastern Germany: Source apportionment and contributions from different spatial scales

NASA Astrophysics Data System (ADS)

van Pinxteren, D.; Fomba, K. W.; Mothes, F.; Spindler, G.; Herrmann, H.

2017-12-01

Understanding the contributions of particulate matter (PM) sources and the source areas impacting total PM levels in a city are important requirements for further developing clean air policies and efficient abatement strategies. This presentation reports on two studies in Eastern Germany providing a detailed picture of present-day urban PM sources and discriminating contributions of local, regional and long-range sources. The "Leipzig Aerosol 2013-15" study yielded contributions of 12 sources to coarse, fine, and ultrafine particles, resolved by Positive Matrix Factorization (PMF) from comprehensive chemical speciation of 5-stage Berner impactor samples at 4 different sites in the Leipzig area. Dominant winter-time sources were traffic exhaust and non-exhaust emissions, secondary aerosol formation, and combustion emissions from both biomass and coal burning with different relative importance in different particle size ranges. Local sources dominated PM levels in ultrafine and coarse particles (60% - 80%) while high mass concentrations in accumulation mode particles mainly resulted from regional import into the city (70%). The "PM-East" study compiled PM10 mass and constituents' concentrations at 10 urban and rural sites in Eastern Germany during winter 2016/17, which included a 3-week episode of frequent exceedances of the PM10 limit value. PMF source apportionment is performed for a subset of the sites, including the city of Berlin. Contributions from short-, mid-, and long-range sources, including trans-boundary pollution import from neighbouring countries, are quantitatively assessed by advanced back trajectory statistical methods. Data analysis in PM-East is ongoing and final results will be available by November. Funding is acknowledged from 4 federal states of Germany: Berlin Senate Department for Environment, Transport and Climate Protection; Saxon State Office for Environment, Agriculture and Geology; State Agency for Environment, Nature Conservation and Geology Mecklenburg-Vorpommern; and Brandenburg State Office for Environment.

Atmospheric Aerosol Source-Receptor Relationships: The Role of Coal-Fired Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

2005-12-01

This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2005 through August 2005. Significant progress was made this project period on the source characterization, source apportionment, and deterministic modeling activities. This report highlights new data on road dust, vegetative detritus and motor vehicle emissions. For example, the results show significant differences in the composition in urban and rural road dust. A comparison of the organic of the fine particulate matter in the tunnel with the ambient provides clear evidence of the significant contribution of vehicle emissions to ambient PM. Themore » source profiles developed from this work are being used by the source-receptor modeling activities. The report presents results on the spatial distribution of PMF-factors. The results can be grouped into three different categories: regional sources, local sources, or potentially both regional and local sources. Examples of the regional sources are the sulfate and selenium PMF-factors which most likely-represent coal fired power plants. Examples of local sources are the specialty steel and lead factors. There is reasonable correspondence between these apportionments and data from the EPA TRI and AIRS emission inventories. Detailed comparisons between PMCAMx predictions and measurements by the STN and IMPROVE measurements in the Eastern US are presented. Comparisons were made for the major aerosol components and PM{sub 2.5} mass in July 2001, October 2001, January 2002, and April 2002. The results are encouraging with average fraction biases for most species less than 0.25. The improvement of the model performance during the last two years was mainly due to the comparison of the model predictions with the continuous measurements in the Pittsburgh Supersite. Major improvements have included the descriptions: of ammonia emissions (CMU inventory), night time nitrate chemistry, EC emissions and their diurnal variation, and nitric acid dry removal.« less

Carbonaceous Aerosol Characterization during 2016 KOR-US 2016

NASA Astrophysics Data System (ADS)

Rodriguez, B.; Santos, G. M.; Sanchez, D.; Jeong, D.; Czimczik, C. I.; Kim, S.

2017-12-01

Atmospheric carbonaceous aerosols are a major component of fine particulate matter and assume important roles in Earth's climate and human health. Because atmospheric carbonaceous aerosols exist as a continuum ranging from small, light-scattering organic carbon (OC), to highly-condensed, light-absorbing elemental carbon (EC) they have contrasting effects on interaction with incoming and outgoing radiation, cloud formation, and snow/ice albedo. By strengthening our understanding of the relative contribution and sources of OC and EC we will be able to further describe aerosol formation and mixing at the regional level. To understand the relative anthropogenic and biogenic contributions to carbonaceous aerosol, 12 PM10 aerosols samples were collected on quartz fiber filters at the Mt. Taewha Research Forest in South Korea during the KORUS-AQ 2016 campaign over periods of 24-48 hours with a high-volume air sampler. Analysis of bulk C and N concentrations and absorption properties of filter extracts interspersed with HYSPLIT model results indicated that continental outflow across the Yellow Sea in enriched in bulk nitrogen loading and enhanced bulk absorptive properties of the aerosols. Bulk radiocarbon analysis also indicated enriched values in all samples indicating contamination from a nuclear power plant or the combustion of biomedical waste nearby. Here, we aim to investigate further the chemical characterization of VOCs adsorbed unto the aerosol through TD-GC-TOFMS. With this dataset we aim to determine the relative contribution of anthropogenic and biogenic aerosols by utilizing specific chemical tracers for source apportionment.

Global Particulate Matter Source Apportionment

NASA Astrophysics Data System (ADS)

Lamancusa, C.; Wagstrom, K.

2017-12-01

As our global society develops and grows it is necessary to better understand the impacts and nuances of atmospheric chemistry, in particular those associated with atmospheric particulate matter. We have developed a source apportionment scheme for the GEOS-Chem global atmospheric chemical transport model. While these approaches have existed for several years in regional chemical transport models, the Global Particulate Matter Source Apportionment Technology (GPSAT) represents the first incorporation into a global chemical transport model. GPSAT runs in parallel to a standard GEOS-Chem run. GPSAT uses the fact that all molecules of a given species have the same probability of undergoing any given process as a core principle. This allows GPSAT to track many different species using only the flux information provided by GEOS-Chem's many processes. GPSAT accounts for the change in source specific concentrations as a result of aqueous and gas-phase chemistry, horizontal and vertical transport, condensation and evaporation on particulate matter, emissions, and wet and dry deposition. By using fluxes, GPSAT minimizes computational cost by circumventing the computationally costly chemistry and transport solvers. GPSAT will allow researchers to address many pertinent research questions about global particulate matter including the global impact of emissions from different source regions and the climate impacts from different source types and regions. For this first application of GPSAT, we investigate the contribution of the twenty largest urban areas worldwide to global particulate matter concentrations. The species investigated include: ammonium, nitrates, sulfates, and the secondary organic aerosols formed by the oxidation of benzene, isoprene, and terpenes. While GPSAT is not yet publically available, we will incorporate it into a future standard release of GEOS-Chem so that all GEOS-Chem users will have access to this new tool.

Argon offline-AMS source apportionment of organic aerosol over yearly cycles for an urban, rural, and marine site in northern Europe

NASA Astrophysics Data System (ADS)

Bozzetti, Carlo; Sosedova, Yuliya; Xiao, Mao; Daellenbach, Kaspar R.; Ulevicius, Vidmantas; Dudoitis, Vadimas; Mordas, Genrik; Byčenkienė, Steigvilė; Plauškaitė, Kristina; Vlachou, Athanasia; Golly, Benjamin; Chazeau, Benjamin; Besombes, Jean-Luc; Baltensperger, Urs; Jaffrezo, Jean-Luc; Slowik, Jay G.; El Haddad, Imad; Prévôt, André S. H.

2017-01-01

The widespread use of Aerodyne aerosol mass spectrometers (AMS) has greatly improved real-time organic aerosol (OA) monitoring, providing mass spectra that contain sufficient information for source apportionment. However, AMS field deployments remain expensive and demanding, limiting the acquisition of long-term datasets at many sampling sites. The offline application of aerosol mass spectrometry entailing the analysis of nebulized water extracted filter samples (offline-AMS) increases the spatial coverage accessible to AMS measurements, being filters routinely collected at many stations worldwide. PM1 (particulate matter with an aerodynamic diameter < 1 µm) filter samples were collected during an entire year in Lithuania at three different locations representative of three typical environments of the southeast Baltic region: Vilnius (urban background), Rūgšteli\\vskis (rural terrestrial), and Preila (rural coastal). Aqueous filter extracts were nebulized in Ar, yielding the first AMS measurements of water-soluble atmospheric organic aerosol (WSOA) without interference from air fragments. This enables direct measurement of the CO+ fragment contribution, whose intensity is typically assumed to be equal to that of CO2+. Offline-AMS spectra reveal that the water-soluble CO2+ : CO+ ratio not only shows values systematically > 1 but is also dependent on season, with lower values in winter than in summer. AMS WSOA spectra were analyzed using positive matrix factorization (PMF), which yielded four factors. These factors included biomass burning OA (BBOA), local OA (LOA) contributing significantly only in Vilnius, and two oxygenated OA (OOA) factors, summer OOA (S-OOA) and background OOA (B-OOA), distinguished by their seasonal variability. The contribution of traffic exhaust OA (TEOA) was not resolved by PMF due to both low concentrations and low water solubility. Therefore, the TEOA concentration was estimated using a chemical mass balance approach, based on the concentrations of hopanes, specific markers of traffic emissions. AMS-PMF source apportionment results were consistent with those obtained from PMF applied to marker concentrations (i.e., major inorganic ions, OC / EC, and organic markers including polycyclic aromatic hydrocarbons and their derivatives, hopanes, long-chain alkanes, monosaccharides, anhydrous sugars, and lignin fragmentation products). OA was the largest fraction of PM1 and was dominated by BBOA during winter with an average concentration of 2 µg m-3 (53 % of OM), while S-OOA, probably related to biogenic emissions, was the prevalent OA component during summer with an average concentration of 1.2 µg m-3 (45 % of OM). PMF ascribed a large part of the CO+ explained variability (97 %) to the OOA and BBOA factors. Accordingly, we discuss a new CO+ parameterization as a function of CO2+ and C2H4O2+ fragments, which were selected to describe the variability of the OOA and BBOA factors.

COLLABORATIVE RESEARCH: Study of Aerosol Sources and Processing at the GVAX Pantnagar Supersite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thornton, Joel A.; Worsnop, Douglas

2016-09-22

This project was part of a collaborative campaign, including the participation of scientists from seven research groups as part of the Winter Intensive Operating Period (January-February 2012) of the Clean Air for London (ClearfLo) campaign at a rural site in Detling, UK, 45 km southeast of central London to study wintertime sources of urban particulate matter. The UW contribution by PI Thornton’s group was to make the first deployment of a chemical ionization mass spectrometer instrument (MOVI-CI-ToFMS) to measure both particle and gas phase organic acids. The new instrument ran nearly continuously during the ClearfLo WINTER IOP at the Detlingmore » site, producing a first-ever data set of molecular composition information that can be used for source apportionment and process studies. The UW group published a paper in Environmental Science and Technology and contributed to another (Bohnenstengel et al BAMS 2015) detailing a direct molecular connection between biomass/biofuel burning particles and aerosol light absorption. The ES&T paper (Mohr, et al ES&T 2013) has received 42 citations in just 3 years indicative of its significant impact on the field. These measurements of urban and rural aerosol properties will contribute to improved modeling of regional aerosol emissions, and of atmospheric aging and removal.« less

Sources of particulate matter in China: Insights from source apportionment studies published in 1987-2017.

PubMed

Zhu, Yanhong; Huang, Lin; Li, Jingyi; Ying, Qi; Zhang, Hongliang; Liu, Xingang; Liao, Hong; Li, Nan; Liu, Zhenxin; Mao, Yuhao; Fang, Hao; Hu, Jianlin

2018-06-01

Particulate matter (PM) in the atmosphere has adverse effects on human health, ecosystems, and visibility. It also plays an important role in meteorology and climate change. A good understanding of its sources is essential for effective emission controls to reduce PM and to protect public health. In this study, a total of 239 PM source apportionment studies in China published during 1987-2017 were reviewed. The documents studied include peer-reviewed papers in international and Chinese journals, as well as degree dissertations. The methods applied in these studies were summarized and the main sources in various regions of China were identified. The trends of source contributions at two major cities with abundant studies over long-time periods were analyzed. The most frequently used methods for PM source apportionment in China are receptor models, including chemical mass balance (CMB), positive matrix factorization (PMF), and principle component analysis (PCA). Dust, fossil fuel combustion, transportation, biomass burning, industrial emission, secondary inorganic aerosol (SIA) and secondary organic aerosol (SOA) are the main source categories of fine PM identified in China. Even though the sources of PM vary among seven different geographical areas of China, SIA, industrial, and dust emissions are generally found to be the top three source categories in 2007-2016. A number of studies investigated the sources of SIA and SOA in China using air quality models and indicated that fossil fuel combustion and industrial emissions were the most important sources of SIA (total contributing 63.5%-88.1% of SO 4 2- , and 47.3%-70% NO 3 - ), and agriculture emissions were the dominant source of NH 4 + (contributing 53.9%-90%). Biogenic emissions were the most important source of SOA in China in summer, while residential and industrial emissions were important in winter. Long-term changes of PM sources at two megacities of Beijing and Nanjing indicated that the contributions of fossil fuel and industrial sources have been declining after stricter emission controls in recent years. In general, dust and industrial contributions decreased and transportation contributions increased after 2000. PM 2.5 emissions are predicted to decline in most regions during 2005-2030, even though the energy consumptions except biomass burning are predicted to continue to increase. Industrial, residential, and biomass burning sources will become more important in the future in the businuess-as-usual senarios. This review provides valuable information about main sources of PM and their trends in China. A few recommendations are suggested to further improve our understanding the sources and to develop effective PM control strategies in various regions of China. Copyright © 2018 Elsevier Ltd. All rights reserved.

Chemical signatures of urban, open burning and dust transportation in an urban environment- megacity in South Asia

NASA Astrophysics Data System (ADS)

Priyadharshini, B.; Verma, S.

2016-12-01

A sub-micron aerosol sampler (SAS) consisting of two parallel stacked filter units (SFU) was deployed at an urban location (Kolkata) to study the sub-micron aerosols (water soluble inorganic ions (WSII) and carbonaceous aerosols (elemental carbon (EC) and organic carbon (OC)) collected over a year (September 2010 to August 2011). Quantification of 10 WSII species using Ion Chromatograph (IC) indicated alkaline nature of aerosols with calcium (Ca2+) being the major neutralizing factor of acidity at the study site. In terms of WSII percentage contribution, the most abundant were crustal species (Ca2+, magnesium (Mg2+) and marine species (chloride (Cl-)), followed by the secondary species sulphate (SO42-), nitrate (NO3-) and ammonium (NH4+) . Ca2+ (fugitive and transported dust) was dominant throughout the study period with K+ concentrations exhibiting seasonality with agricultural residue burning. Further, results of carbonaceous aerosols analyzed using the OC-EC aerosol analyzer following Interagency Monitoring of Protected Visual Environment (IMPROVE) protocol exhibited pronounced seasonality in OC than EC with the overall mean concentration of OC being three folds than EC. Primary organic carbon (POC) and secondary organic carbon concentrations (SOC) estimated using EC tracer method showed 57% (43%) of POC (SOC) from various emission sources. Investigation of OC/EC ratio along with non-sea salt potassium (nss-K+) values revealed influence of season specific anthropogenic activities on both OC and EC concentrations (viz. Open burning (OB)) besides fossil fuel (FF) and biofuel (BF) usage for cooking and heating prevalent over the region. Source apportionment was discerned using positive matrix factorization (PMF) with four major factors (crustal, agricultural, anthropogenic sources and mixed source (crustal + agriculture + anthropogenic) as the primary contributors to the sub-micron aerosols at the study site.

Mass spectra features of biomass burning boiler and coal burning boiler emitted particles by single particle aerosol mass spectrometer.

PubMed

Xu, Jiao; Li, Mei; Shi, Guoliang; Wang, Haiting; Ma, Xian; Wu, Jianhui; Shi, Xurong; Feng, Yinchang

2017-11-15

In this study, single particle mass spectra signatures of both coal burning boiler and biomass burning boiler emitted particles were studied. Particle samples were suspended in clean Resuspension Chamber, and analyzed by ELPI and SPAMS simultaneously. The size distribution of BBB (biomass burning boiler sample) and CBB (coal burning boiler sample) are different, as BBB peaks at smaller size, and CBB peaks at larger size. Mass spectra signatures of two samples were studied by analyzing the average mass spectrum of each particle cluster extracted by ART-2a in different size ranges. In conclusion, BBB sample mostly consists of OC and EC containing particles, and a small fraction of K-rich particles in the size range of 0.2-0.5μm. In 0.5-1.0μm, BBB sample consists of EC, OC, K-rich and Al_Silicate containing particles; CBB sample consists of EC, ECOC containing particles, while Al_Silicate (including Al_Ca_Ti_Silicate, Al_Ti_Silicate, Al_Silicate) containing particles got higher fractions as size increase. The similarity of single particle mass spectrum signatures between two samples were studied by analyzing the dot product, results indicated that part of the single particle mass spectra of two samples in the same size range are similar, which bring challenge to the future source apportionment activity by using single particle aerosol mass spectrometer. Results of this study will provide physicochemical information of important sources which contribute to particle pollution, and will support source apportionment activities. Copyright © 2017. Published by Elsevier B.V.

Seasonal variability in chemical composition and source apportionment of sub-micron aerosol over a high altitude site in Western Ghats, India

NASA Astrophysics Data System (ADS)

Mukherjee, Subrata; Singla, Vyoma; Pandithurai, Govindan; Safai, P. D.; Meena, G. S.; Dani, K. K.; Anil Kumar, V.

2018-05-01

This manuscript reports the seasonal variation of chemically speciated sub-micron aerosol particles (diameter < 1 μm). An Aerosol Chemical Speciation Monitor (ACSM) was used to measure the mass concentration of non-refractory particulate matter (NR-PM1) at a high-altitude site in the Western Ghats, India from March 2016 to February 2017. The mass concentration of NR-PM1 averaged at 7.5 ± 6.5 μgm-3, with major contributions from organics (59%) and sulfates (23%). Positive matrix factorization (PMF) was applied on the measured mass spectra of organic aerosol (OA) to derive the sources distinctive of each season (Summer, Monsoon, Post-Monsoon and Winter). The four OA factors (two primary OA and two oxygenated OA) resolved during summer, post-monsoon and winter season. However, only one oxygenated factor resolved during monsoon and contributed only 20% to the total OA. The factors associated with primary emissions dominated during the monsoon, whereas factors related to secondary formation dominated in other three seasons. During summer, an isoprene derived SOA - IEPOX-OA (isoprene-epoxydiol OA) contributed ∼17% to the total OA. Cluster and concentration weighted trajectory (CWT) analyses were performed to identify the possible source regions of NR-PM1 mass concentration observed at the receptor site. The analysis identifies Central India as the potential source region of transported aerosol during post-monsoon and winter season. Our study suggests that contributions from both local sources and regional transport are important in governing mass concentration of PM1 over Mahabaleshwar.

Isotopic evidence for enhanced fossil fuel sources of aerosol ammonium in the urban atmosphere.

PubMed

Pan, Yuepeng; Tian, Shili; Liu, Dongwei; Fang, Yunting; Zhu, Xiaying; Gao, Meng; Gao, Jian; Michalski, Greg; Wang, Yuesi

2018-07-01

The sources of aerosol ammonium (NH 4 + ) are of interest because of the potential of NH 4 + to impact the Earth's radiative balance, as well as human health and biological diversity. Isotopic source apportionment of aerosol NH 4 + is challenging in the urban atmosphere, which has excess ammonia (NH 3 ) and where nitrogen isotopic fractionation commonly occurs. Based on year-round isotopic measurements in urban Beijing, we show the source dependence of the isotopic abundance of aerosol NH 4 + , with isotopically light (-33.8‰) and heavy (0 to +12.0‰) NH 4 + associated with strong northerly winds and sustained southerly winds, respectively. On an annual basis, 37-52% of the initial NH 3 concentrations in urban Beijing arises from fossil fuel emissions, which are episodically enhanced by air mass stagnation preceding the passage of cold fronts. These results provide strong evidence for the contribution of non-agricultural sources to NH 3 in urban regions and suggest that priority should be given to controlling these emissions for haze regulation. This study presents a carefully executed application of existing stable nitrogen isotope measurement and mass-balance techniques to a very important problem: understanding source contributions to atmospheric NH 3 in Beijing. This question is crucial to informing environmental policy on reducing particulate matter concentrations, which are some of the highest in the world. However, the isotopic source attribution results presented here still involve a number of uncertain assumptions and they are limited by the incomplete set of chemical and isotopic measurements of gas NH 3 and aerosol NH 4 + . Further field work and lab experiments are required to adequately characterize endmember isotopic signatures and the subsequent isotopic fractionation process under different air pollution and meteorological conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Spatially and chemically resolved source apportionment analysis: Case study of high particulate matter event

NASA Astrophysics Data System (ADS)

Kim, Byeong-Uk; Bae, Changhan; Kim, Hyun Cheol; Kim, Eunhye; Kim, Soontae

2017-08-01

This article presents the results of a detailed source apportionment study of the high particulate matter (PM) event in the Seoul Metropolitan Area (SMA), South Korea, during late February 2014. Using the Comprehensive Air Quality Model with Extensions with its Particulate Source Apportionment Technology (CAMx-PSAT), we defined 10 source regions, including five in China, for spatially and chemically resolved analyses. During the event, the spatially averaged PM10 concentration at all PM10 monitors in the SMA was 129 μg/m3, while the PM10 and PM2.5 concentrations at the BulGwang Supersite were 143 μg/m3 and 123 μg/m3, respectively. CAMx-PSAT showed reasonably good PM model performance in both China and the SMA. For February 23-27, CAMx-PSAT estimated that Chinese contributions to the SMA PM10 and PM2.5 were 84.3 μg/m3 and 80.0 μg/m3, respectively, or 64% and 70% of the respective totals, while South Korea's respective domestic contributions were 36.5 μg/m3 and 23.3 μg/m3. We observed that the spatiotemporal pattern of PM constituent concentrations and contributions did not necessarily follow that of total PM10 and PM2.5 concentrations. For example, Beijing-Tianjin-Hebei produced high nitrate concentrations, but the two most-contributing regions to PM in the SMA were the Near Beijing area and South Korea. In addition, we noticed that the relative contributions from each region changed over time. We found that most ammonium mass that neutralized Chinese sulfate mass in the SMA came from South Korean sources, indicating that secondary inorganic aerosol in the SMA, especially ammonium sulfates, during this event resulted from different major precursors originating from different regions.

Chemical characterization and source apportionment of fine and coarse particulate matter in Lahore, Pakistan

NASA Astrophysics Data System (ADS)

Stone, Elizabeth; Schauer, James; Quraishi, Tauseef A.; Mahmood, Abid

2010-03-01

Lahore, Pakistan is an emerging megacity that is heavily polluted with high levels of particle air pollution. In this study, respirable particulate matter (PM 2.5 and PM 10) were collected every sixth day in Lahore from 12 January 2007 to 19 January 2008. Ambient aerosol was characterized using well-established chemical methods for mass, organic carbon (OC), elemental carbon (EC), ionic species (sulfate, nitrate, chloride, ammonium, sodium, calcium, and potassium), and organic species. The annual average concentration (±one standard deviation) of PM 2.5 was 194 ± 94 μg m -3 and PM 10 was 336 ± 135 μg m -3. Coarse aerosol (PM 10-2.5) was dominated by crustal sources like dust (74 ± 16%, annual average ± one standard deviation), whereas fine particles were dominated by carbonaceous aerosol (organic matter and elemental carbon, 61 ± 17%). Organic tracer species were used to identify sources of PM 2.5 OC and chemical mass balance (CMB) modeling was used to estimate relative source contributions. On an annual basis, non-catalyzed motor vehicles accounted for more than half of primary OC (53 ± 19%). Lesser sources included biomass burning (10 ± 5%) and the combined source of diesel engines and residual fuel oil combustion (6 ± 2%). Secondary organic aerosol (SOA) was an important contributor to ambient OC, particularly during the winter when secondary processing of aerosol species during fog episodes was expected. Coal combustion alone contributed a small percentage of organic aerosol (1.9 ± 0.3%), but showed strong linear correlation with unidentified sources of OC that contributed more significantly (27 ± 16%). Brick kilns, where coal and other low quality fuels are burned together, are suggested as the most probable origins of unapportioned OC. The chemical profiling of emissions from brick kilns and other sources unique to Lahore would contribute to a better understanding of OC sources in this megacity.

Ubiquitous influence of wildfire emissions and secondary organic aerosol on summertime atmospheric aerosol in the forested Great Lakes region

NASA Astrophysics Data System (ADS)

Gunsch, Matthew J.; May, Nathaniel W.; Wen, Miao; Bottenus, Courtney L. H.; Gardner, Daniel J.; VanReken, Timothy M.; Bertman, Steven B.; Hopke, Philip K.; Ault, Andrew P.; Pratt, Kerri A.

2018-03-01

Long-range aerosol transport affects locations hundreds of kilometers from the point of emission, leading to distant particle sources influencing rural environments that have few major local sources. Source apportionment was conducted using real-time aerosol chemistry measurements made in July 2014 at the forested University of Michigan Biological Station near Pellston, Michigan, a site representative of the remote forested Great Lakes region. Size-resolved chemical composition of individual 0.5-2.0 µm particles was measured using an aerosol time-of-flight mass spectrometer (ATOFMS), and non-refractory aerosol mass less than 1 µm (PM1) was measured with a high-resolution aerosol mass spectrometer (HR-AMS). The field site was influenced by air masses transporting Canadian wildfire emissions and urban pollution from Milwaukee and Chicago. During wildfire-influenced periods, 0.5-2.0 µm particles were primarily aged biomass burning particles (88 % by number). These particles were heavily coated with secondary organic aerosol (SOA) formed during transport, with organics (average O/C ratio of 0.8) contributing 89 % of the PM1 mass. During urban-influenced periods, organic carbon, elemental carbon-organic carbon, and aged biomass burning particles were identified, with inorganic secondary species (ammonium, sulfate, and nitrate) contributing 41 % of the PM1 mass, indicative of atmospheric processing. With current models underpredicting organic carbon in this region and biomass burning being the largest combustion contributor to SOA by mass, these results highlight the importance for regional chemical transport models to accurately predict the impact of long-range transported particles on air quality in the upper Midwest, United States, particularly considering increasing intensity and frequency of Canadian wildfires.

Source apportionment of PM2.5 light extinction in an urban atmosphere in China.

PubMed

Lan, Zijuan; Zhang, Bin; Huang, Xiaofeng; Zhu, Qiao; Yuan, Jinfeng; Zeng, Liwu; Hu, Min; He, Lingyan

2018-01-01

Haze in China is primarily caused by high pollution of atmospheric fine particulates (PM 2.5 ). However, the detailed source structures of PM 2.5 light extinction have not been well established, especially for the roles of various organic aerosols, which makes haze management lack specified targets. This study obtained the mass concentrations of the chemical compositions and the light extinction coefficients of fine particles in the winter in Dongguan, Guangdong Province, using high time resolution aerosol observation instruments. We combined the positive matrix factor (PMF) analysis model of organic aerosols and the multiple linear regression method to establish a quantitative relationship model between the main chemical components, in particular the different sources of organic aerosols and the extinction coefficients of fine particles with a high goodness of fit (R 2 =0.953). The results show that the contribution rates of ammonium sulphate, ammonium nitrate, biomass burning organic aerosol (BBOA), secondary organic aerosol (SOA) and black carbon (BC) were 48.1%, 20.7%, 15.0%, 10.6%, and 5.6%, respectively. It can be seen that the contribution of the secondary aerosols is much higher than that of the primary aerosols (79.4% versus 20.6%) and are a major factor in the visibility decline. BBOA is found to have a high visibility destroying potential, with a high mass extinction coefficient, and was the largest contributor during some high pollution periods. A more detailed analysis indicates that the contribution of the enhanced absorption caused by BC mixing state was approximately 37.7% of the total particle absorption and should not be neglected. Copyright © 2017. Published by Elsevier B.V.

Source apportionment of lead-containing aerosol particles in Shanghai using single particle mass spectrometry.

PubMed

Zhang, Yaping; Wang, Xiaofei; Chen, Hong; Yang, Xin; Chen, Jianmin; Allen, Jonathan O

2009-01-01

Lead (Pb) in individual aerosol particles was measured using single particle aerosol mass spectrometer (ATOFMS) in the summer of 2007 in Shanghai, China. Pb was found in 3% of particles with diameters in the range 0.1-2.0 microm. Single particle data were analyzed focusing on the particles with high Pb content which were mostly submicron. Using the ART-2a neural network algorithm, these fine Pb-rich particles were classified into eight main classes by their mass spectral patterns. Based on the size distribution, temporal variation of number density, chemical composition and the correlation between different chemical species for each class, three major emission sources were identified. About 45% of the Pb-rich particles contained organic or elemental carbon and were attributed to the emission from coal combustion; particles with good correlation between Cl and Pb content were mostly attributed to waste incineration. One unique class of particles was identified by strong phosphate and Pb signals, which were assigned to emissions from phosphate industry. Other Pb-rich particles included aged sea salt and particles from metallurgical processes.

The application of chemical and isotopic tracers to characterize aerosol sources and processing in marine air

NASA Astrophysics Data System (ADS)

Turekian, Vaughan Charles

2000-12-01

Aerosol production, transport, chemical and physical evolution and deposition impact the environment by influencing radiation budgets, altering the composition of the atmosphere, and delivering nutrients to marine and terrestrial ecosystems. The objective of this research was to combine high-resolution chemical measurements with stable isotopic analysis in order to characterize the sources and processing of carbon, nitrogen and sulfur bearing compounds, associated with sized aerosols on Bermuda, during spring. Chemical tracers combined with forward and backward trajectories demonstrated the transport of biomass burning products from North America to Bermuda. The size distributions of NH4+ from 1998 differed from those during spring, 1997, a year without the large-scale burning. These results suggest that transport of biomass burning products altered the pH of the aerosols. Marine and continentally derived carbon was associated with all aerosol size fractions. Supermicron radius sea- salt aerosol was enriched in marine derived carbon by 2 orders of magnitude compared to bulk surface seawater. Enrichments of oxalate relative to methanesulfonic acid (MSA) in supermicron radius aerosol suggested in situ formation of oxalate within the sea-salt solution, or direct injection from the organic rich surface microlayer. Compound specific isotope analysis of oxalic acid, indicated a marine source for all aerosol size fractions, indicating formation from in the gas phase for the submicron radius aerosol. Stable sulfur isotopes indicated that the biogenic non- sea-salt (nss) SO42-/MSA ratio varied with aerosol size indicating that MSA may not be a conservative tracer of biogenic nss SO4 2- in bulk aerosol sampling. The calculated biogenic nss SO 42-/MSA based on stable isotopes and sized aerosol sampling, was 3 times lower than previous estimates for Bermuda. Stable nitrogen isotope values for submicron and supermicron aerosol where significantly different, consistent with their different chemical compositions. Results suggested that HNO3 incorporation into supermicron aerosol was essentially unidirectional whereas submicron aerosol was both a source and a sink for NH3(g). Variable aerosol liquid water content over the relatively longer atmospheric lifetimes of submicron aerosol may lead to multiple NH3 phase changes. This study was the first to combine sized aerosol sampling, high-resolution chemical analysis and multiple stable isotopes to characterize both the sources and the processing of aerosols in marine air. The results of this study, therefore, provide crucial information for source apportionment of environmentally important atmospheric species in continentally impacted, marine air.

Origins of aerosol chlorine during winter over north central Colorado, USA

NASA Astrophysics Data System (ADS)

Jordan, C. E.; Pszenny, A. A. P.; Keene, W. C.; Cooper, O. R.; Deegan, B.; Maben, J.; Routhier, M.; Sander, R.; Young, A. H.

2015-01-01

The Nitrogen, Aerosol Composition, and Halogens on a Tall Tower campaign (February-March 2011) near Boulder, Colorado, investigated nighttime ClNO2 production and processing. Virtually all particulate Cl was in the form of ionic Cl-. The size distributions of Cl- and Na+ were similar, with most of the mass in the supermicrometer size fraction, suggesting primary sources for both. Median Cl- concentrations were about half those of Na+ and Ca2+ for particle diameters centered at 1.4 and 2.5 µm. To investigate potential sources of Na+ and Cl-, four cases were studied that featured the prevalence of Na+ and Cl- and different transport pathways based on FLEXible PARTicle dispersion model (FLEXPART) retroplumes. Estimates of supermicrometer Na+ particle lifetime against deposition indicate that long-range transport of marine aerosols could account for the observed Na+. However, measured molar ratios of Ca2+ to Na+ (0.143-0.588) compared to seawater (0.022) indicate significant contributions from crustal sources to the supermicrometer aerosol composition during these four case studies. Further, low molar ratios of Mg2+ to Na+ (0.007-0.098) relative to seawater (0.114) suggest that some of the Na+, and presumably associated Cl-, originated from non-sea-salt sources. The heterogeneous chemical composition of saline soils throughout the western U.S., along with the nonlinearity of wind-driven soil deflation as a function of various surface soil properties, precludes a quantitative apportionment of soil, marine, and anthropogenic sources to the observed coarse-fraction aerosol. Nonetheless, results suggest that deflation of saline soils was a potentially important source of particulate Cl- that sustained atmospheric ClNO2 production and associated impacts on oxidation processes over northern Colorado.

Fine particulates over South Asia: Review and meta-analysis of PM2.5 source apportionment through receptor model.

PubMed

Singh, Nandita; Murari, Vishnu; Kumar, Manish; Barman, S C; Banerjee, Tirthankar

2017-04-01

Fine particulates (PM 2.5 ) constitute dominant proportion of airborne particulates and have been often associated with human health disorders, changes in regional climate, hydrological cycle and more recently to food security. Intrinsic properties of particulates are direct function of sources. This initiates the necessity of conducting a comprehensive review on PM 2.5 sources over South Asia which in turn may be valuable to develop strategies for emission control. Particulate source apportionment (SA) through receptor models is one of the existing tool to quantify contribution of particulate sources. Review of 51 SA studies were performed of which 48 (94%) were appeared within a span of 2007-2016. Almost half of SA studies (55%) were found concentrated over few typical urban stations (Delhi, Dhaka, Mumbai, Agra and Lahore). Due to lack of local particulate source profile and emission inventory, positive matrix factorization and principal component analysis (62% of studies) were the primary choices, followed by chemical mass balance (CMB, 18%). Metallic species were most regularly used as source tracers while use of organic molecular markers and gas-to-particle conversion were minimum. Among all the SA sites, vehicular emissions (mean ± sd: 37 ± 20%) emerged as most dominating PM 2.5 source followed by industrial emissions (23 ± 16%), secondary aerosols (22 ± 12%) and natural sources (20 ± 15%). Vehicular emissions (39 ± 24%) also identified as dominating source for highly polluted sites (PM 2.5 >100 μgm -3 , n = 15) while site specific influence of either or in combination of industrial, secondary aerosols and natural sources were recognized. Source specific trends were considerably varied in terms of region and seasonality. Both natural and industrial sources were most influential over Pakistan and Afghanistan while over Indo-Gangetic plain, vehicular, natural and industrial emissions appeared dominant. Influence of vehicular emission was found single dominating source over southern part while over Bangladesh, both vehicular, biomass burning and industrial sources were significant. Copyright © 2016 Elsevier Ltd. All rights reserved.

Source Apportionment of the Size-Fractionated Urban Aerosols in and around Kolkata, India

NASA Astrophysics Data System (ADS)

Sarkar, Ujjaini; Haque, Monirul; Roy, Rajdeep; Chakraborty, Sanjoy

Our main objective was to estimate the heavy metals like the Lead, Mercury, Cadmium, Sodium, Potassium, Calcium, Aluminium, and Iron, in addition to ammonium, chloride, nitrate, and sulphate ions, by Atomic Absorption Spectrophotometry and Ion Chromatography and apportion the most probable sources using the Chemical Mass Balance Model. The three urban locations of Behala Chowrasta, Rabindra Sadan, and Shyam Bazaar Five Points were chosen within the city of Kolkata. One rural location was chosen at the Indian Institute of Technology campus, Kharagpur, a rural site in the Midnapur District of the state of West Bengal, India. The results look quite encouraging.

Chemical Composition and Source Apportionment of Size ...

EPA Pesticide Factsheets

The Cleveland airshed comprises a complex mixture of industrial source emissions that contribute to periods of non-attainment for fine particulate matter (PM 2.5 ) and are associated with increased adverse health outcomes in the exposed population. Specific PM sources responsible for health effects however are not fully understood. Size-fractionated PM (coarse, fine, and ultrafine) samples were collected using a ChemVol sampler at an urban site (G.T. Craig (GTC)) and rural site (Chippewa Lake (CLM)) from July 2009 to June 2010, and then chemically analyzed. The resulting speciated PM data were apportioned by EPA positive matrix factorization to identify emission sources for each size fraction and location. For comparisons with the ChemVol results, PM samples were also collected with sequential dichotomous and passive samplers, and evaluated for source contributions to each sampling site. The ChemVol results showed that annual average concentrations of PM, elemental carbon, and inorganic elements in the coarse fraction at GTC were ~ 2, ~7, and ~3 times higher than those at CLM, respectively, while the smaller size fractions at both sites showed similar annual average concentrat ions. Seasonal variations of secondary aerosols (e.g., high N03- level in winter and high SO42- level in summer) were observed at both sites. Source apportionment results demonstrated that the PM samples at GTC and CLM were enriched with local industrial sources (e.g., steel plant and coa

Source Apportionment of Atmospheric Particles by Electron Probe X-Ray Microanalysis and Receptor Models.

NASA Astrophysics Data System (ADS)

van Borm, Werner August

Electron probe X-ray microanalysis (EPXMA) in combination with an automation system and an energy-dispersive X-ray detection system was used to analyse thousands of microscopical particles, originating from the ambient atmosphere. The huge amount of data was processed by a newly developed X-ray correction method and a number of data reduction procedures. A standardless ZAF procedure for EPXMA was developed for quick semi-quantitative analysis of particles starting from simple corrections, valid for bulk samples and modified taking into account the particle finit diameter, assuming a spherical shape. Tested on a limited database of bulk and particulate samples, the compromise between calculation speed and accuracy yielded for elements with Z > 14 accuracies on concentrations less than 10% while absolute deviations remained below 4 weight%, thus being only important for low concentrations. Next, the possibilities for the use of supervised and unsupervised multivariate particle classification were investigated for source apportionment of individual particles. In a detailed study of the unsupervised cluster analysis technique several aspects were considered, that have a severe influence on the final cluster analysis results, i.e. data acquisition, X-ray peak identification, data normalization, scaling, variable selection, similarity measure, cluster strategy, cluster significance and error propagation. A supervised approach was developed using an expert system-like approach in which identification rules are builded to describe the particle classes in a unique manner. Applications are presented for particles sampled (1) near a zinc smelter (Vieille-Montagne, Balen, Belgium), analyzed for heavy metals, (2) in an urban aerosol (Antwerp, Belgium), analyzed for over 20 elements and (3) in a rural aerosol originating from a swiss mountain area (Bern). Thus is was possible to pinpoint a number of known and unknown sources and characterize their emissions in terms of particles abundance and particle composition. Alternatively, the bulk analysis of filters (total, fine and coarse mode) using Particle Induced X -Ray Emission (PIXE) and the application of a receptor modeling approach provided for complementary information on a macroscopical level. A computer program was developed incorporating an absolute factor analysis based receptor modeling procedure. Source profiles and contributions are described by elemental concentrations and an atmospheric mass balance is put forward. The latter method was applied in a two year study of the Antwerp urban aerosol and for the swiss aerosol, revealing a number of previously known and unknown sources. Both methods were successfully combined to increase the source resolution.

Source apportionment of particulate pollutants in the atmosphere over the Northern Yellow Sea

NASA Astrophysics Data System (ADS)

Wang, L.; Qi, J. H.; Shi, J. H.; Chen, X. J.; Gao, H. W.

2013-05-01

Atmospheric aerosol samples were collected over the Northern Yellow Sea of China during the years of 2006 and 2007, in which the Total Carbon (TC), Cu, Pb, Cd, V, Zn, Fe, Al, Na+, Ca2+, Mg2+, NH4+, NO3-, SO42-, Cl-, and K+ were measured. The principle components analysis (PCA) and positive matrix factorization (PMF) receptor models were used to identify the sources of particulate matter. The results indicated that seven factors contributed to the atmospheric particles over the Northern Yellow Sea, i.e., two secondary aerosols (sulfate and nitrate), soil dust, biomass burning, oil combustion, sea salt, and metal smelting. When the whole database was considered, secondary aerosol formation contributed the most to the atmospheric particle content, followed by soil dust. Secondary aerosols and soil dust consisted of 65.65% of the total mass of particulate matter. The results also suggested that the aerosols over the North Yellow Sea were heavily influenced by ship emission over the local sea area and by continental agricultural activities in the northern China, indicating by high loading of V in oil combustion and high loading of K+ in biomass burning. However, the contribution of each factor varied greatly over the different seasons. In spring and autumn, soil dust and biomass burning were the dominant factors. In summer, heavy oil combustion contributed the most among these factors. In winter, secondary aerosols were major sources. Backward trajectories analysis indicated the 66% of air mass in summer was from the ocean, while the air mass is mainly from the continent in other seasons.

Single particle mass spectral signatures from vehicle exhaust particles and the source apportionment of on-line PM2.5 by single particle aerosol mass spectrometry.

PubMed

Yang, Jian; Ma, Shexia; Gao, Bo; Li, Xiaoying; Zhang, Yanjun; Cai, Jing; Li, Mei; Yao, Ling'ai; Huang, Bo; Zheng, Mei

2017-09-01

In order to accurately apportion the many distinct types of individual particles observed, it is necessary to characterize fingerprints of individual particles emitted directly from known sources. In this study, single particle mass spectral signatures from vehicle exhaust particles in a tunnel were performed. These data were used to evaluate particle signatures in a real-world PM 2.5 apportionment study. The dominant chemical type originating from average positive and negative mass spectra for vehicle exhaust particles are EC species. Four distinct particle types describe the majority of particles emitted by vehicle exhaust particles in this tunnel. Each particle class is labeled according to the most significant chemical features in both average positive and negative mass spectral signatures, including ECOC, NaK, Metal and PAHs species. A single particle aerosol mass spectrometry (SPAMS) was also employed during the winter of 2013 in Guangzhou to determine both the size and chemical composition of individual atmospheric particles, with vacuum aerodynamic diameter (d va ) in the size range of 0.2-2μm. A total of 487,570 particles were chemically analyzed with positive and negative ion mass spectra and a large set of single particle mass spectra was collected and analyzed in order to identify the speciation. According to the typical tracer ions from different source types and classification by the ART-2a algorithm which uses source fingerprints for apportioning ambient particles, the major sources of single particles were simulated. Coal combustion, vehicle exhaust, and secondary ion were the most abundant particle sources, contributing 28.5%, 17.8%, and 18.2%, respectively. The fraction with vehicle exhaust species particles decreased slightly with particle size in the condensation mode particles. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of polar organic compounds and source analysis of fine organic aerosols in Hong Kong

NASA Astrophysics Data System (ADS)

Li, Yunchun

Organic aerosols, as an important fraction of airborne particulate mass, significantly affect the environment, climate, and human health. Compared with inorganic species, characterization of individual organic compounds is much less complete and comprehensive because they number in thousands or more and are diverse in chemical structures. The source contributions of organic aerosols are far from being well understood because they can be emitted from a variety of sources as well as formed from photochemical reactions of numerous precursors. This thesis work aims to improve the characterization of polar organic compounds and source apportionment analysis of fine organic carbon (OC) in Hong Kong, which consists of two parts: (1) An improved analytical method to determine monocarboxylic acids, dicarboxylic acids, ketocarboxylic acids, and dicarbonyls collected on filter substrates has been established. These oxygenated compounds were determined as their butyl ester or butyl acetal derivatives using gas chromatography-mass spectrometry. The new method made improvements over the original Kawamura method by eliminating the water extraction and evaporation steps. Aerosol materials were directly mixed with the BF 3/BuOH derivatization agent and the extracting solvent hexane. This modification improves recoveries for both the more volatile and the less water-soluble compounds. This improved method was applied to study the abundances and sources of these oxygenated compounds in PM2.5 aerosol samples collected in Hong Kong under different synoptic conditions during 2003-2005. These compounds account for on average 5.2% of OC (range: 1.4%-13.6%) on a carbon basis. Oxalic acid was the most abundant species. Six C2 and C3 oxygenated compounds, namely oxalic, malonic, glyoxylic, pyruvic acids, glyoxal, and methylglyoxal, dominated this suite of oxygenated compounds. More efforts are therefore suggested to focus on these small compounds in understanding the role of oxygenated compounds in aerosol chemistry and physics. By reference to tracers for the major organic aerosol sources, it is deduced that the oxygenated compounds are mainly of secondary origin and direct/indirect contribution from biomass burning could also be important. The chemical composition of these oxygenated species in PM2.5 samples in Hong Kong provide useful information to further ambient and model study in the aspects of chemical formation pathways and speciated organic mass distribution. (2) Source apportionment of PM2.5 organic aerosols in Hong Kong were carried out in two studies. In the first study, chemical characterization and source analysis involved samples collected on high particulate matter (PM) days (avg. PM 2.5 >84 mug m-3) at six general stations and one roadside station from October to December in 2003. Analysis of synoptic weather conditions identified three types of high PM episodes: local, regional transport (RT) and long-range transport (LRT). Roadside samples were discussed separately. Using chemical mass balance (CMB) model, contributions of major primary sources (vehicle exhaust, cooking, biomass burning, cigarette smoke, vegetative detritus, and coal combustion) were estimated, which indicate that vehicle exhaust was the most important primary source, followed by cooking and biomass burning. All primary sources except vegetative detritus had the highest contributions at roadside station, in line with its site characteristics. Primary sources dominated roadside and local samples (>64% of fine OC), while un-apportioned OC (i.e., the difference between measured OC and apportioned primary OC) dominated RT and LRT episodes (>60% of fine OC) and un-apportioned OC had characteristics of secondary OC. In the second study, cold front episodes during winter 2004 and 2005 were targeted to investigate the effect of cold front-related LRT on chemical characteristics and organic aerosol sources of PM2.5 in Hong Kong. In comparison with days under influences of mainly local emissions or RT, cold front LRT brought more organic aerosols attributable to coal combustion and biomass burning. Both cold front episodes and RT brought in significant amount of secondary OC to Hong Kong. The relative abundances of major aerosol constituents (sulfate, nitrate, ammonium, organic matter, and elemental carbon) were similar in cold front periods and RT-dominated periods.

Development and Application of Novel Sampling Methodologies for Study of Volatile Particulate Matter in Military Aircraft Emissions

DTIC Science & Technology

2012-09-01

experiments. J. Aerosol Sci., 40, 603- 612. Zheng, M., Cass, G. R., Schauer, J. J., Edgerton, E. S. (2002) Source Apportionment of PM2.5 in the...Energy Heavy Vehicle Research Program. The SERDP project WP1627 team consists of the following members (listed in alphabetical order of the last name...aircraft emissions are dominated by a fleet of high payload aircraft, such as the C-130, B1 B-52, and a variety of heavy -lift turboshaft vehicles

Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

DOE PAGES

Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; ...

2015-07-16

We measured a large suite of gas- and particle-phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas andmore » particle phases, the latter being detected by temperature-programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO–HR-ToF-CIMS are highly correlated with, and explain at least 25–50 % of, the organic aerosol mass measured by an Aerodyne aerosol mass spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from high molecular weight organics and/or oligomers (i.e., multi-phase accretion reaction products). Approximately 50 % of the HR-ToF-CIMS particle-phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption-temperature-based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.« less

Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

DOE PAGES

Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; ...

2015-02-18

We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gasmore » and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25–50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas–particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.« less

A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG)

DOE PAGES

Zhang, Yaping; Williams, Brent J.; Goldstein, Allen H.; ...

2016-11-25

Here, we present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG) system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes) (Zhang et al., 2014). Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arrangedmore » into an input data matrix for positive matrix factorization (PMF), where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins) are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS), TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level resolution on other bulk aerosol components commonly observed by the AMS.« less

A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG)

NASA Astrophysics Data System (ADS)

Zhang, Yaping; Williams, Brent J.; Goldstein, Allen H.; Docherty, Kenneth S.; Jimenez, Jose L.

2016-11-01

We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography-mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG) system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes) (Zhang et al., 2014). Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF), where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins) are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS), TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level resolution on other bulk aerosol components commonly observed by the AMS.

Physicochemical variations in atmospheric aerosols recorded at sea onboard the Atlantic-Mediterranean 2008 Scholar Ship cruise (Part II): Natural versus anthropogenic influences revealed by PM 10 trace element geochemistry

NASA Astrophysics Data System (ADS)

Moreno, Teresa; Pérez, Noemi; Querol, Xavier; Amato, Fulvio; Alastuey, Andrés; Bhatia, Ravinder; Spiro, Baruch; Hanvey, Melanie; Gibbons, Wes

2010-07-01

The geochemistry of PM 10 filter samples collected at sea during the Scholar Ship Atlantic-Mediterranean 2008 research cruise reveals a constantly changing compositional mix of pollutants into the marine atmosphere. Source apportionment modelling using Positive Matrix Factorization identifies North African desert dust, sea spray, secondary inorganic aerosols, metalliferous carbon, and V-Ni-bearing combustion particles as the main PM 10 factors/sources. The least contaminated samples show an upper continental crust composition (UCC)-normalised geochemistry influenced by seawater chemistry, with marked depletions in Rb, Th and the lighter lanthanoid elements, whereas the arrival of desert dust intrusions imposes a more upper crustal signature enriched in "geological" elements such as Si, Al, Ti, Rb, Li and Sc. Superimposed on these natural background aerosol loadings are anthropogenic metal aerosols (e.g. Cu, Zn, Pb, V, and Mn) which allow identification of pollution sources such as fossil fuel combustion, biomass burning, metalliferous industries, and urban-industrial ports. A particularly sensitive tracer is La/Ce, which rises in response to contamination from coastal FCC oil refineries. The Scholar Ship database allows us to recognise seaborne pollution sourced from NW Africa, the Cape Verde and Canary islands, and European cities and industrial complexes, plumes which in extreme cases can produce a downwind deterioration in marine air quality comparable to that seen in many cities, and can persist hundreds of kilometres from land.

Chemical and microphysical properties of the aerosol during foggy and nonfoggy episodes: a relationship between organic and inorganic content of the aerosol

NASA Astrophysics Data System (ADS)

Kaul, D. S.; Gupta, T.; Tripathi, S. N.

2012-06-01

An extensive field measurement during winter was carried out at a site located in the Indo-Gangetic Plain (IGP) which gets heavily influenced by the fog during winter almost every year. The chemical and microphysical properties of the aerosols during foggy and nonfoggy episodes and chemical composition of the fogwater are presented. Positive matrix factorization (PMF) as a tool for the source apportionment was employed to understand the sources of pollution. Four major sources viz. biomass burning, refractory, secondary and mineral dust were identified. Aerosols properties during foggy episodes were heavily influenced by almost all the sources and they caused considerable loading of almost all the organic and inorganic species during the period. The biomass generated aerosols were removed from the atmosphere by scavenging during foggy episodes. The wet removal of almost all the species by the fog droplets was observed. The K+, water soluble organic carbon (WSOC), water soluble inorganic carbon (WSIC) and NO3- were most heavily scavenged among the species and their concentrations consequently became lower than the nonfoggy episode concentrations. The production of secondary inorganic aerosol, mainly sulfate and ammonium, during foggy episodes was considerably higher than nitrate which was rather heavily scavenged and removed by the fog droplets. The fogwater analysis showed that dissolved inorganic species play a vital role in processing of organic carbon such as the formation of organo-sulfate and organo-nitrate inside the fog droplets. The formation of organo-sulfate and organo-nitrate in aerosol and the influence of acidity on the secondary organic aerosol (SOA) formation were rather found to be negligible. The study average inorganic component of the aerosol was considerably higher than the carbonaceous component during both foggy and nonfoggy episode. The secondary production of the aerosol changed the microphysical properties of aerosol which was reflected by increase in the modal diameter of the size distribution during foggy episodes and growth in the diameter of the particles upon the fog evaporation.

Size-resolved source apportionment of carbonaceous particulate matter in urban and rural sites in central California

NASA Astrophysics Data System (ADS)

Ham, Walter A.; Kleeman, Michael J.

2011-08-01

Very little is currently known about the relationship between exposure to different sources of ambient ultrafine particles (PM 0.1) and human health effects. If human health effects are enhanced by PM 0.1's ability to cross cell membranes, then more information is needed describing the sources of ultrafine particles that are deposited in the human respiratory system. The current study presents results for the source apportionment of airborne particulate matter in six size fractions smaller than 1.8 μm particle diameter including ultrafine particles (PM 0.1) in one of the most polluted air basins in the United States. Size-resolved source apportionment results are presented at an urban site and rural site in central California's heavily polluted San Joaquin Valley during the winter and summer months using a molecular marker chemical mass balance (MM-CMB) method. Respiratory deposition calculations for the size-resolved source apportionment results are carried out with the Multiple Path Particle Dosimetry Model ( MPPD v 2.0), including calculations for ultrafine (PM 0.1) source deposition. Diesel engines accounted for the majority of PM 0.1 and PM 1.8 EC at both the urban and rural sampling locations during both summer and winter seasons. Meat cooking accounted for 33-67% and diesel engines accounted for 15-21% of the PM 0.1 OC at Fresno. Meat cooking accounted for 22-26% of the PM 0.1 OC at the rural Westside location, while diesel engines accounted for 8-9%. Wood burning contributions to PM 0.1 OC increased to as much as 12% of PM 0.1 OC during the wintertime. The modest contribution of wood smoke reflects the success of emissions control programs over the past decade. In contrast to PM 0.1, PM 1.8 OC had a higher fraction of unidentified source contributions (68-85%) suggesting that this material is composed of secondary organic aerosol (SOA) or primary organic aerosol (POA) that has been processed by atmospheric chemical reactions. Meat cooking was the largest identified source of PM 1.8 organic carbon (OC) at the Fresno site (12-13%) while diesel engines were the largest identified PM 1.8 OC source at the rural site (5-8%). Wood burning contributions to PM 1.8 OC increased during the wintertime at both sites (6-9%) but were relatively small during the summertime (˜1%). As expected, diesel engines were the dominant source of PM 0.1 EC respiratory deposition at both the urban and rural site in both summer and winter (0.01-0.03 μg PM 0.1 EC deposited per m 3 air inhaled). Meat cooking accounted for 0.01-0.025 μg PM 0.1 OC deposited per m 3 air inhaled while diesel fuel accounted for 0.005-0.013 μg PM 0.1 OC deposited per m 3 air inhaled. Minor contributions from wood burning, motor oil, and gasoline fuel were calculated at levels <0.005 μg PM 0.1 OC deposited per m 3 air inhaled at both urban and rural locations during winter and summer seasons. If the burden of PM 0.1 deposited in the respiratory system is relevant for human health effects, then future toxicology studies should be carried out at PM 0.1 concentrations and source mixtures equivalent to those measured in the current study.

Chemical characterization and source apportionment of submicron aerosols measured in Senegal during the 2015 SHADOW campaign

NASA Astrophysics Data System (ADS)

Rivellini, Laura-Hélèna; Chiapello, Isabelle; Tison, Emmanuel; Fourmentin, Marc; Féron, Anaïs; Diallo, Aboubacry; N'Diaye, Thierno; Goloub, Philippe; Canonaco, Francesco; Prévôt, André Stephan Henry; Riffault, Véronique

2017-09-01

The present study offers the first chemical characterization of the submicron (PM1) fraction in western Africa at a high time resolution, thanks to collocated measurements of nonrefractory (NR) species with an Aerosol Chemical Speciation Monitor (ACSM), black carbon and iron concentrations derived from absorption coefficient measurements with a 7-wavelength Aethalometer, and total PM1 determined by a TEOM-FDMS (tapered element oscillating microbalance-filtered dynamic measurement system) for mass closure. The field campaign was carried out over 3 months (March to June 2015) as part of the SHADOW (SaHAran Dust Over West Africa) project at a coastal site located in the outskirts of the city of Mbour, Senegal. With an averaged mass concentration of 5.4 µg m-3, levels of NR PM1 in Mbour were 3 to 10 times lower than those generally measured in urban and suburban polluted environments. Nonetheless the first half of the observation period was marked by intense but short pollution events (NR PM1 concentrations higher than 15 µg m-3), sea breeze phenomena and Saharan desert dust outbreaks (PM10 up to 900 µg m-3). During the second half of the campaign, the sampling site was mainly under the influence of marine air masses. The air masses on days under continental and sea breeze influences were dominated by organics (36-40 %), whereas sulfate particles were predominant (40 %) for days under oceanic influence. Overall, measurements showed that about three-quarters of the total PM1 were explained by NR PM1, BC (black carbon) and Fe (a proxy for dust) concentrations, leaving approximately one-quarter for other refractory species. A mean value of 4.6 % for the Fe / PM1 ratio was obtained. Source apportionment of the organic fraction, using positive matrix factorization (PMF), highlighted the impact of local combustion sources, such as traffic and residential activities, which contribute on average to 52 % of the total organic fraction. A new organic aerosol (OA) source, representing on average 3 % of the total OA fraction, showed similar variation to nonrefractory particulate chloride. Its rose plot and daily pattern pointed to local combustion processes, i.e., two open waste-burning areas located about 6 and 11 km away from the receptor site and to a lesser extent a traditional fish-smoking location. The remaining fraction was identified as oxygenated organic aerosols (OOA), a factor that prevailed regardless of the day type (45 %) and was representative of regional (approximately three-quarters) but also local (approximately one-quarter) sources due to enhanced photochemical processes.

Study of atmospheric aerosols by IBA techniques: The LABEC experience

NASA Astrophysics Data System (ADS)

Lucarelli, F.; Calzolai, G.; Chiari, M.; Nava, S.; Carraresi, L.

2018-02-01

At the 3 MV Tandetron accelerator of the LABEC laboratory of INFN (Florence, Italy) an external beam facility is fully dedicated to PIXE-PIGE measurements of the elemental composition of atmospheric aerosols. All the elements with Z > 10 are simultaneously detected by PIXE typically in one minute. This setup allows us an easy automatic positioning, changing and scanning of samples collected by different kinds of devices: long series of daily PM (Particulate Matter) samples can be analysed in short times, as well as size-segregated and high time-resolution aerosol samples. Thanks to the capability of detecting all the crustal elements, PIXE-PIGE analyses are unrivalled in the study of mineral dust: consequently, they are very effective in the study of natural aerosols, like, for example, Saharan dust intrusions. Among the detectable elements there are also important markers of anthropogenic sources, which allow effective source apportionment studies in polluted urban environments using a multivariate method like Positive Matrix Factorization (PMF). Examples regarding recent monitoring campaigns, performed in urban and remote areas, both daily and with high time resolution (hourly samples), as well as with size selection, are presented. The importance of the combined use of the Particle Induced Gamma Ray emission technique (PIGE) and of other complementary (non-nuclear) techniques is highlighted.

Open air mineral treatment operations and ambient air quality: assessment and source apportionment.

PubMed

Escudero, M; Alastuey, A; Moreno, T; Querol, X; Pérez, P

2012-11-01

We present a methodology for evaluating and quantifying the impact of inhalable mineral dust resuspension close to a potentially important industrial point source, in this case an open air plant producing sand, flux and kaolin in the Capuchinos district of Alcañiz (Teruel, NE Spain). PM(10) levels at Capuchinos were initially high (42 μg m(-3) as the annual average with 91 exceedances of the EU daily limit value during 2007) but subsequently decreased (26 μg m(-3) with 16 exceedances in 2010) due to a reduced demand for minerals from the ceramic industry and construction sector during the first stages of the economic crisis. Back trajectory and local wind pattern analyses revealed only limited contribution from exotic PM sources such as African dust intrusions whereas there was clearly a strong link with the mineral stockpiles of the local industry. This link was reinforced by chemical and mineral speciation and source apportionment analysis which showed a dominance of mineral matter (sum of CO(3)(2-), SiO(2), Al(2)O(3), Ca, Fe, K, Mg, P, and Ti: mostly aluminosilicates) which in 2007 contributed 76% of the PM(10) mass (44 μg m(-3) on average). The contribution from Secondary Inorganic Aerosols (SIA, sum of SO(4)(2-), NO(3)(-) and NH(4)(+)) reached 8.4 μg m(-3), accounting for 14% of the PM(10) mass, similar to the amount of calcareous road dust estimated to be present (8 μg m(-3); 13%). Organic matter and elemental carbon contributed 5.3 μg m(-3) (9%) whereas marine aerosol (Na + Cl) levels were minor with an average concentration of 0.4 μg m(-3) (1% of the PM(10) mass). Finally, chemical and mineralogical analysis of stockpile samples and comparison with filter samples confirmed the local industry to be the major source of ambient PM(10) in the area.

Fine particle receptor modeling in the atmosphere of Mexico City.

PubMed

Vega, Elizabeth; Lowenthal, Douglas; Ruiz, Hugo; Reyes, Elizabeth; Watson, John G; Chow, Judith C; Viana, Mar; Querol, Xavier; Alastuey, Andrés

2009-12-01

Source apportionment analyses were carried out by means of receptor modeling techniques to determine the contribution of major fine particulate matter (PM2.5) sources found at six sites in Mexico City. Thirty-six source profiles were determined within Mexico City to establish the fingerprints of particulate matter sources. Additionally, the profiles under the same source category were averaged using cluster analysis and the fingerprints of 10 sources were included. Before application of the chemical mass balance (CMB), several tests were carried out to determine the best combination of source profiles and species used for the fitting. CMB results showed significant spatial variations in source contributions among the six sites that are influenced by local soil types and land use. On average, 24-hr PM2.5 concentrations were dominated by mobile source emissions (45%), followed by secondary inorganic aerosols (16%) and geological material (17%). Industrial emissions representing oil combustion and incineration contributed less than 5%, and their contribution was higher at the industrial areas of Tlalnepantla (11%) and Xalostoc (8%). Other sources such as cooking, biomass burning, and oil fuel combustion were identified at lower levels. A second receptor model (principal component analysis, [PCA]) was subsequently applied to three of the monitoring sites for comparison purposes. Although differences were obtained between source contributions, results evidence the advantages of the combined use of different receptor modeling techniques for source apportionment, given the complementary nature of their results. Further research is needed in this direction to reach a better agreement between the estimated source contributions to the particulate matter mass.

Source apportionment of particulate organic matter using infrared spectra at multiple IMPROVE sites

NASA Astrophysics Data System (ADS)

Kuzmiakova, A.; Dillner, A. M.; Takahama, S.

2016-12-01

As organic aerosol is a dominant contributor to air pollution and radiative forcing in many regions in the United States, characterizing its composition and apportioning the organic mass to its major sources provides insight into atmospheric processes and guidance for decreasing its abundance. National networks, such as Interagency Monitoring of Protected Visual Environment (IMPROVE), provide multi-site and multi-year particulate matter samples useful for evaluating sources over all four seasons. To this end, our study focuses on apportioning the particulate organic matter (OM) to specific anthropogenic and biological processes from year-long infrared aerosol measurements collected at six IMPROVE sites (five national park sites and one urban site) during 2011. Pooling these organic aerosol samples into one dataset, we apply factor and cluster analyses to extract four chemical factors (two dominated by processed emissions, one dominated by hydroxyl groups, and one by hydrocarbons) and ascribe each factor to a specific source depending on the site and season. We also present a method to characterize measurement uncertainty in infrared instrumental analysis and investigate sensitivity analysis in generated factors. In Phoenix (the urban site) we find the majority (80-95%) of the OM consisted of anthropogenic activities, such as traffic emissions, fossil fuel combustion (both all year long), and residential wood burning (fall to winter). Mineral dust emissions accounted for the rest of OM (5-20%). At the National Park sites the OM concentration was lower on average and consisted of marine and dust aerosols, summertime biomass burning and biogenic aerosols, processed fossil fuel combustion, and emissions from ships and oil refineries. Our study highlights the potential for further site-specific or multi-year aerosol characterization in the context of a long-term atmospheric sampling program to quantify sources of organic particles impacting air quality, aid in policy-making, and assess which (trans)formation mechanisms proposed in laboratory studies are consistent with observations.

Chemical characterization and source apportionment of fine particulate matter in Yangzhou, China, using offline aerosol mass spectrometry

NASA Astrophysics Data System (ADS)

Li, L.; Ge, X.; Xu, J.; Ye, Z.

2016-12-01

In recent years, Aerodyne Aerosol Mass Spectrometer (AMS) has been widely used for online and real-time monitoring of fine aerosol particles all over the world. However, due to the high cost and complex maintenance, the AMS was typically deployed for short-term intense field measurements, limiting its ability in elucidating the long-term behaviors and dominant sources of regional fine particles (PM2.5). In this study, we collected daily PM2.5 filter samples across a relatively long period (November 2015 to April 2016, in total >100 samples) using a high-volume sampler, in urban Yangzhou - a city in the Yangtze River Delta region, China. These samples were analyzed by using a suite of analytical techniques, for the water-soluble inorganic ions (WSIs), organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and total nitrogen (TN), trace metal elements, etc. More importantly, an Aerodyne soot particle aerosol mass spectrometer (SP-AMS) was for the first time introduced for the offline characterization of the PM2.5 samples collected in this region. In particular, Positive matrix factorization was conducted on the SP-AMS determined water-soluble fraction of organic aerosols (WSOA), and three distinct sources were separated, including a primary OA (POA), a less oxygenated OA (LOOA), and a more oxygenated OA (MOOA). Chemical characteristics and evolution processes of these OA subcomponents were further discussed. Our results are useful for the air pollution management in the YRD region, and the technique developed can be applied elsewhere as well.

Carbon isotope-constrained seasonality of carbonaceous aerosol sources from an urban location (Kanpur) in the Indo-Gangetic Plain

NASA Astrophysics Data System (ADS)

Bikkina, Srinivas; Andersson, August; Ram, Kirpa; Sarin, M. M.; Sheesley, Rebecca J.; Kirillova, Elena N.; Rengarajan, R.; Sudheer, A. K.; Gustafsson, Örjan

2017-05-01

The Indo-Gangetic Plain (IGP) in northern India, Pakistan, and Bangladesh is a major source of carbonaceous aerosols in South Asia. However, poorly constrained seasonality of their sources over the IGP leads to large uncertainty in climate and health effects. Here we present a first data set for year-round radiocarbon (Δ14C) and stable carbon (δ13C)-based source apportionment of total carbon (TC) in ambient PM10 (n = 17) collected from an urban site (Kanpur: 26.5°N, 80.3°E) in the IGP during January 2007 to January 2008. The year-round 14C-based fraction biomass (fbio-TC) estimate at Kanpur averages 77 ± 7% and emphasizes an impact of biomass burning emissions (BBEs). The highest fbio-TC (%) is observed in fall season (October-November, 85 ± 6%) followed by winter (December-February, 80 ± 4%) and spring (March-May, 75 ± 8%), while lowest values are found in summer (June-September, 69 ± 2%). Since biomass/coal combustion and vehicular emissions mostly contribute to carbonaceous aerosols over the IGP, we predict δ13CTC (δ13Cpred) over Kanpur using known δ13C source signatures and the measured Δ14C value of each sample. The seasonal variability of δ13Cobs - δ13Cpred versus Δ14CTC together with air mass back trajectories and Moderate Resolution Imaging Spectroradiometer fire count data reveal that carbonaceous aerosols in winter/fall are significantly influenced by atmospheric aging (downwind transport of crop residue burning/wood combustion emissions in the northern IGP), while local sources (wheat residue combustion/vehicular emissions) dominate in spring/summer. Given the large temporal and seasonal variability in sources and emission strength of TC over the IGP, 14C-based constraints are, thus, crucial for reducing their uncertainties in carbonaceous aerosol budgets in climate models.

Characterization of the wintertime particulate (PM1) pollution at an urban background site of Nicosia, Cyprus

NASA Astrophysics Data System (ADS)

Pikridas, Michael; Sciare, Jean; Vrekoussis, Mihalis; Oikonomou, Konstantina; Merabet, Hamza; Mihalopoulos, Nikos; Yassaa, Nouredine; Savvides, Chrysanthos

2016-04-01

As part of MISTRALS-ChArMEx (Chemistry-Aerosol Mediterranean Experiment, http://charmex.lsce.ipsl.fr/), and MISTRALS-ENVI-Med "CyAr" (Cyprus Aerosols and gas precursors) programs, a 1-month intensive field campaign has been performed in December 2014 at an urban background site of Nicosia (Cyprus) - a typical European city of the Eastern Mediterranean - with the objective to document the major (local versus imported) sources responsible for wintertime particulate (PM1) pollution. Several near real-time analyzers were deployed for that purpose (TEOM 1400, OPC Grimm 1.108, Q-ACSM, Aethalometer AE31) allowing to investigate in near-real time the major chemical components of submicron aerosols (Black Carbon, Organics, Sulphate, Nitrate, Ammonium). Quality control of Q-ACSM and Aethalometer datasets was performed through closure studies (using co-located TEOM / OPC Grimm). Comparisons were also performed with other on-line / off-line measurements performed by the local Air quality network (DLI) at other locations in Nicosia with the objective to check the consistency and representativeness of our observations. Very high levels of Black Carbon and OA were systematically observed every night (with maximum concentrations around 22:00 local time) pointing to local combustion sources most probably related to domestic heating. Source apportionment of organic aerosols (OA) was performed using the SourceFinder software (SoFi, http://www.psi.ch/acsm-stations/me-2) allowing the distinction between various primary/secondary OA sources and helped us to better characterize the combustion sources being responsible for the observed elevated nighttime PM1 levels. Acknowledgements: This campaign has been funded by MISTRALS (ChArMEx et ENVI-Med CyAr programs), CNRS-INSU, CEA, CyI, DLI, CDER and ECPL.

Integrated Forensics Approach to Fingerprint PCB Sources in Sediments using Rapid Sediment Characterization (RSC) and Advanced Chemical Fingerprinting (ACF)

DTIC Science & Technology

2012-06-01

Source Compositions for HPS Dataset ...........................................78 Figure 25 Comparison of Source Apportionment for HPS Dataset...The similarity in the three source patterns from HPS makes the apportionment less certain at that site compared to the four source patterns at... apportionment of these sources across the site. Overall these techniques passed all the performance assessment tests that are presented in Section 6. 3.3

Physico-chemical properties of aerosols in Sao Paulo, Brazil and mechanisms of secondary organic aerosol formation.

NASA Astrophysics Data System (ADS)

Artaxo, Paulo; Ferreira de Brito, Joel; Varanda Rizzo, Luciana; Luiza Godoy, Maria; Godoy, Jose Marcus

2013-04-01

Megacities emissions are increasingly becoming a global issue, where emissions from the transportation sector play an increasingly important role. Sao Paulo is a megacity with a population of about 18 million people, 7 million cars and large-scale industrial emissions. As a result of the vehicular and industrial emissions, the air quality in Sao Paulo is bellow WMO standards for aerosol particles and ozone. Many uncertainties are found on gas- and particulate matter vehicular emission factors and their following atmospheric processes, e.g. secondary organic aerosol formation. Due to the uniqueness of the vehicular fuel in Brazil, largely based on ethanol use, such characterization currently holds further uncertainties. To improve the understanding of the role of this unique emission characteristics, we are running a source apportionment study in Sao Paulo focused on the mechanisms of organic aerosol formation. One of the goals of this study is a quantitative aerosol source apportionment focused on vehicular emissions, including ethanol and gasohol (both fuels used by light-duty vehicles). This study comprises four sampling sites with continuous measurements for one year, where trace elements and organic aerosol are being measured for PM2.5 and PM10 along with real-time NOx, O3, PM10 and CO measurements. Aerosol optical properties and size distribution are being measured on a rotation basis between sampling stations. Furthermore, a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) and an Aerosol Chemical Speciation Monitor (ACSM) are used to measure in real time VOCs and aerosol composition, respectively. Trace elements were measured using XRF and OC/EC analysis was determined with a Sunset OC/EC instrument. A TSI Nephelometer with 3 wavelengths measure light scattering and a MAAP measure black carbon. Results show aerosol number concentrations ranging between 10,000 and 35,000 cm-3, mostly concentrated in the nucleation and Aitken modes, with a peak in size at 80-120 nm. Average mass concentrations were measured at 11.5 ug/m3 and 30.7 ug/m3 for fine and coarse mode, respectively. The elemental analysis shows that Fe, Si and Al dominate the coarse mode indicating strong contribution from soil dust resuspension whereas sulfur dominates the fine mode (0.8 micrograms/m3). Scattering coefficients typically range between 20 and 150 Mm-1 at 637 nm, and absorption varied between 10 to 60 Mm-1 at 637 nm, respectively, both of them peaking at 7:00 local time, the morning rush hour. The corresponding single scattering albedo varies between 0.50 and 0.80, indicating a significant contribution of primary soot particles to the aerosol population. Organic aerosol accounts for 70% of the aerosol mass, with nitrates accounting for 11.7%, ammonia 8.4%, sulfate 8.2% and chlorine 1.6% pf PM1 measured by AMS techniques. Most of the organic aerosol were oxygenated. Several new particle formation events were observed, with a clear increase in organic aerosol and VOCs amounts associated with new particle formation. The study allows the characterization of a unique fueled fleet emissions and its impact on atmospheric chemistry, particle formation and other atmospheric dynamic processes. This work was funded by Petrobras S/A

An inter-comparison of PM2.5 at urban and urban background sites: Chemical characterization and source apportionment

NASA Astrophysics Data System (ADS)

Cesari, D.; Donateo, A.; Conte, M.; Merico, E.; Giangreco, A.; Giangreco, F.; Contini, D.

2016-06-01

A measurement campaign was performed between 04/03/2013 and 17/07/2013 for simultaneous collection of PM2.5 samples in two nearby sites in southeastern Italy: an urban site and an urban background site. PM2.5 at the two sites were similar; however, the chemical composition and the contributions of the main sources were significantly different. The coefficients of divergence (CODs) showed spatial heterogeneity of EC (higher at the urban site because of traffic emissions) and of all metals. Major ions (NH4+, Na+, and SO42 -) and OC had low CODs, suggesting a homogeneous distribution of sea spray, secondary sulfate, and secondary organic matter (SOM = 1.6*OCsec, where OCsec is the secondary OC). The strong correlations between Na+ and Cl-, and the low Cl-/Na+ ratios, suggested the presence of aged sea spray with chloride depletion (about 79% of Cl-) and formation of sodium nitrate at both sites. In both sites, the non-sea-salt sulfate was about 97% of sulfate, and the strong correlation between SO42 - and NH4+ indicated that ammonium was present as ammonium sulfate. However, during advection of Saharan Dust, calcium sulfate was present rather than ammonium sulfate. The source apportionment was performed using the Positive Matrix Factorization comparing outputs of model EPA PMF 3.0 and 5.0 version. Six aerosol sources were identified at both sites: traffic, biomass burning, crustal-resuspended dust, secondary nitrate, marine aerosol, and secondary sulfate. The PMF3.0 model was not completely able, in these sites, to separate marine contribution from secondary nitrate and secondary sulfate from OC, underestimating the marine contribution and overestimating the secondary sulfate with respect to stoichiometric calculations. The application of specific constraints on PMF5.0 provided cleaner profiles, improving the comparison with stoichiometric calculations. The seasonal trends revealed larger biomass burning contributions during the cold period at both sites due to domestic heating emissions added to those of agricultural practices. Secondary aerosol represented about 50% of PM2.5 at both sites (about 1/3 due to SOM), with a slight increase during the cold season, probably due to the formation of secondary OC via gas-to-particle conversion. Secondary inorganic aerosol (nitrate plus sulfate) did not show seasonal trend because the reduction of nitrate due to thermal instability during the warm season was compensated by an almost equivalent increase of sulfate.

Construction of Fine Particles Source Spectrum Bank in Typical Region and Empirical Research of Matching Diagnosis

NASA Astrophysics Data System (ADS)

Wang, Xing; Sun, Wenliang; Guo, Min; Li, Minjiao; Li, Wan

2018-01-01

The research object of this paper is fine particles in typical region. The construction of component spectrum bank is based on the technology of online source apportionment, then the result of the apportionment is utilized to verify the effectiveness of fine particles component spectrum bank and which also act as the matching basis of online source apportionment receptor sample. On the next, the particle source of air pollution is carried through the matching diagnosis empirical research by utilizing online source apportionment technology, to provide technical support for the cause analysis and treatment of heavy pollution weather.

Realtime chemical characterization of post monsoon organic aerosols in a polluted urban city: Sources, composition, and comparison with other seasons.

PubMed

Chakraborty, Abhishek; Mandariya, Anil Kumar; Chakraborti, Ruparati; Gupta, Tarun; Tripathi, S N

2018-01-01

Real time chemical characterization of non-refractory submicron aerosols (NR-PM 1 ) was carried out during post monsoon (September-October) via Aerosol Mass Spectrometer (AMS) at a polluted urban location of Kanpur, India. Organic aerosol (OA) was found to be the dominant species with 58% contribution to total NR-PM 1 mass, followed by sulfate (16%). Overall, OA was highly oxidized (average O/C = 0.66) with the dominance of oxidized OAs (60% of total OA) as revealed by source apportionment. Oxidized nature of OA was also supported by very high OC/EC ratios (average = 8.2) obtained from simultaneous offline filter sampling. High and low OA loading periods have very dramatic effects on OA composition and oxidation. OA O/C ratios during lower OA loading periods were on average 30% higher than the same from high loading periods with significant changes in types and relative contribution from oxidized OAs (OOA). Comparison of OA sources and chemistry among post monsoon and other seasons revealed significant differences. Characteristics of primary OAs remain very similar, but features of OOAs showed substantial changes from one season to another. Winter had lowest OOA contribution to total OA but similar overall O/C ratios as other seasons. This reveals that processing of primary OAs, local atmospheric chemistry, and regional contributions can significantly alter OA characteristics from one season to another. This study provides interesting insights into the seasonal variations of OA sources and evolution in a very polluted and complex environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Monitoring and source apportionment of trace elements in PM2.5: Implications for local air quality management.

PubMed

Li, Yueyan; Chang, Miao; Ding, Shanshan; Wang, Shiwen; Ni, Dun; Hu, Hongtao

2017-07-01

Fine particulate matter (PM 2.5 ) samples were collected simultaneously every hour in Beijing between April 2014 and April 2015 at five sites. Thirteen trace elements (TEs) in PM 2.5 were analyzed by online X-ray fluorescence (XRF). The annual average PM 2.5 concentrations ranged from 76.8 to 102.7 μg m -3 . TEs accounted for 5.9%-8.7% of the total PM 2.5 mass with Cl, S, K, and Si as the most dominant elements. Spearman correlation coefficients of PM 2.5 or TE concentrations between the background site and other sites showed that PM 2.5 and some element loadings were affected by regional and local sources, whereas Cr, Si, and Ni were attributed to substantial local emissions. Temporal variations of TEs in PM 2.5 were significant and provided information on source profiles. The PM 2.5 concentrations were highest in autumn and lowest in summer. Mn and Cr showed similar variation. Fe, Ca, Si, and Ti tended to show higher concentrations in spring, whereas concentrations of S peaked in summer. Concentrations of Cl, K, Pb, Zn, Cu, and Ni peaked in winter. PM 2.5 and TE median concentrations were higher on Saturdays than on weekdays. The diurnal pattern of PM 2.5 and TE median concentrations yielded similar bimodal patterns. Five dominant sources of PM 2.5 mass were identified via positive matrix factorization (PMF). These sources included the regional and local secondary aerosols, traffic, coal burning, soil dust, and metal processing. Air quality management strategies, including regional environmental coordination and collaboration, reduction in secondary aerosol precursors, restrictive vehicle emission standards, promotion of public transport, and adoption of clean energy, should be strictly implemented. High time-resolution measurements of TEs provided detailed source profiles, which can greatly improve precision in interpreting source apportionment calculations; the PMF analysis of online XRF data is a powerful tool for local air quality management. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anomalous elevated radiocarbon measurements of PM2.5

NASA Astrophysics Data System (ADS)

Buchholz, Bruce A.; Fallon, Stewart J.; Zermeño, Paula; Bench, Graham; Schichtel, Bret A.

2013-01-01

Two-component models are often used to determine the contributions made by fossil fuel and natural sources of carbon in airborne particulate matter (PM). The models reduce thousands of actual sources to two end members based on isotopic signature. Combustion of fossil fuels produces PM free of carbon-14 (14C). Wood or charcoal smoke, restaurant fryer emissions, and natural emissions from plants produce PM with the contemporary concentration of 14C approximately 1.2 × 10-1214C/C. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading and radiocarbon analysis is becoming a popular source apportionment method. Emissions from incinerators combusting medical or biological wastes containing tracer 14C can skew the 14C/C ratio of PM, however, so critical analysis of sampling sites for possible sources of elevated PM needs to be completed prior to embarking on sampling campaigns. Results are presented for two ambient monitoring sites in different areas of the United States where 14C contamination is apparent. Our experience suggests that such contamination is uncommon but is also not rare (∼10%) for PM sampling sites.

Sources of non-fossil-fuel emissions in carbonaceous aerosols during early winter in Chinese cities

NASA Astrophysics Data System (ADS)

Liu, Di; Li, Jun; Cheng, Zhineng; Zhong, Guangcai; Zhu, Sanyuan; Ding, Ping; Shen, Chengde; Tian, Chongguo; Chen, Yingjun; Zhi, Guorui; Zhang, Gan

2017-09-01

China experiences frequent and severe haze outbreaks from the beginning of winter. Carbonaceous aerosols are regarded as an essential factor in controlling the formation and evolution of haze episodes. To elucidate the carbon sources of air pollution, source apportionment was conducted using radiocarbon (14C) and unique molecular organic tracers. Daily 24 h PM2. 5 samples were collected continuously from October 2013 to November 2013 in 10 Chinese cities. The 14C results indicated that non-fossil-fuel (NF) emissions were predominant in total carbon (TC; average = 65 ± 7 %). Approximately half of the EC was derived primarily from biomass burning (BB) (average = 46 ± 11 %), while over half of the organic carbon (OC) fraction comprised NF (average = 68 ± 7 %). On average, the largest contributor to TC was NF-derived secondary OC (SOCnf), which accounted for 46 ± 7 % of TC, followed by SOC derived from fossil fuels (FF) (SOCf; 16 ± 3 %), BB-derived primary OC (POCbb; 13 ± 5 %), POC derived from FF (POCf; 12 ± 3 %), EC derived from FF (ECf; 7 ± 2 %) and EC derived from BB (ECbb; 6 ± 2 %). The regional background carbonaceous aerosol composition was characterized by NF sources; POCs played a major role in northern China, while SOCs contributed more in other regions. However, during haze episodes, there were no dramatic changes in the carbon source or composition in the cities under study, but the contribution of POC from both FF and NF increased significantly.

Source apportionment of atmospheric particulate matter (PM) using a constrained US-EPA-PMF5.0 model at different urban environments in France

NASA Astrophysics Data System (ADS)

Salameh, Dalia; Favez, Olivier; Golly, Benjamin; Besombes, Jean Luc; Alleman, Laurent; Albinet, Alexandre; Jaffrezo, Jean Luc

2017-04-01

Particulate matter (PM) is one of the most studied atmospheric pollutant in urban areas due to their adverse effects on human health (Pope et al., 2009). Intrinsic properties of PM (e.g. chemical composition and morphology) are directly linked to their origins. Therefore, a harmonized and comprehensive apportionment study of PM sources in urban environments is extremely required to connect source contributions with PM concentration levels and then develop effective PM abatement strategies. Multivariate receptor models such as Positive Matrix Factorization (PMF) are very useful and have been used worldwide for PM source apportionment (Viana et al., 2008). PMF uses a weighted least-squares fit and quantitatively determines source fingerprints (factors) and their contributions to the total PM mass. However, in many cases, it could be tricky to separate two factors that co-vary due to similar seasonal variations, making unclear the physical sense of the extracted factors. To address such issues of source collinearities, additional specific constraints are incorporated into the model (i.e., constrained PMF) based on user's external knowledge allowing better apportionment results. In this work and within the framework of the SOURCES project, a harmonized source apportionment approach has been implemented and applied for the determination of PM sources on a large number of sites (up to 20) of different typologies (e.g. urban background, industrial, traffic, rural and/or alpine sites) distributed all over France and previously investigated with annual or multiannual studies (2012-2016). A constrained PMF approach (using US-EPA PMF5.0 software) was applied to the comprehensive PM-offline chemical datasets (i.e. carbonaceous fraction, major ions, metals/trace elements, specific organic markers) in a harmonized way for all the investigated sites. Different types of specific chemical constraints from well-characterized sources were defined based on external knowledge and were imposed to some species in the PMF factor profiles. As an example, the contributions of the levoglucosan, a specific tracer of the biomass burning emissions, were pulled up maximally in the biomass burning factor profiles and were set to zero in all other resolved factors (e.g. vehicular emissions, biogenic emissions, etc,…). The different source categories contributing to ambient PM concentration levels were chemically characterized and quantified. Chemical profiles of the resolved common sources have been exploited and compared allowing us to get extra knowledge on the spatial variabilities of the source compositions. The presentation will address the main points achieved with this program. Pope, I. C., et al. (2009), New England Journal of Medicine, 360(4), 376-386. Viana, M., et al. (2008), Journal of Aerosol Science, 39(10), 827-849. Acknowledgments: This work, including a postdoctoral grant for D Salameh, is funded by the French Ministry of Environment, Energy, and Sea (MEEM) through the Environment and Energy Management Agency (ADEME, contract 1462C0044) and the national reference laboratory for air quality monitoring (LCSQA). The authors also gratefully acknowledge the funding by ANDRA of the program conducted at OPE by S Conil, and all dedicated staffs within the French regional monitoring networks for collecting the samples.

Fine particulate matter in the tropical environment: monsoonal effects, source apportionment, and health risk assessment

NASA Astrophysics Data System (ADS)

Khan, M. F.; Latif, M. T.; Saw, W. H.; Amil, N.; Nadzir, M. S. M.; Sahani, M.; Tahir, N. M.; Chung, J. X.

2016-01-01

The health implications of PM2.5 in the tropical region of Southeast Asia (SEA) are significant as PM2.5 can pose serious health concerns. PM2.5 concentration and sources here are strongly influenced by changes in the monsoon regime from the south-west quadrant to the north-east quadrant in the region. In this work, PM2.5 samples were collected at a semi-urban area using a high-volume air sampler at different seasons on 24 h basis. Analysis of trace elements and water-soluble ions was performed using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. Apportionment analysis of PM2.5 was carried out using the United States Environmental Protection Agency (US EPA) positive matrix factorization (PMF) 5.0 and a mass closure model. We quantitatively characterized the health risks posed to human populations through the inhalation of selected heavy metals in PM2.5. 48 % of the samples collected exceeded the World Health Organization (WHO) 24 h PM2.5 guideline but only 19 % of the samples exceeded 24 h US EPA National Ambient Air Quality Standard (NAAQS). The PM2.5 concentration was slightly higher during the north-east monsoon compared to south-west monsoon. The main trace metals identified were As, Pb, Cd, Ni, Mn, V, and Cr while the main ions were SO42-, NO3-, NH4+, and Na. The mass closure model identified four major sources of PM2.5 that account for 55 % of total mass balance. The four sources are mineral matter (MIN) (35 %), secondary inorganic aerosol (SIA) (11 %), sea salt (SS) (7 %), and trace elements (TE) (2 %). PMF 5.0 elucidated five potential sources: motor vehicle emissions coupled with biomass burning (31 %) were the most dominant, followed by marine/sulfate aerosol (20 %), coal burning (19 %), nitrate aerosol (17 %), and mineral/road dust (13 %). The hazard quotient (HQ) for four selected metals (Pb, As, Cd, and Ni) in PM2.5 mass was highest in PM2.5 mass from the coal burning source and least in PM2.5 mass originating from the mineral/road dust source. The main carcinogenic heavy metal of concern to health at the current location was As; the other heavy metals (Ni, Pb, and Cd) did not pose a significant cancer risk in PM2.5 mass concentration. Overall, the associated lifetime cancer risk posed by the exposure of hazardous metals in PM2.5 is 3-4 per 1 000 000 people at this location.

Comparative source apportionment of PM10 in Switzerland for 2008/2009 and 1998/1999 by Positive Matrix Factorisation

NASA Astrophysics Data System (ADS)

Gianini, M. F. D.; Fischer, A.; Gehrig, R.; Ulrich, A.; Wichser, A.; Piot, C.; Besombes, J.-L.; Hueglin, C.

2012-07-01

PM10 speciation data from various sites in Switzerland for two time periods (January 1998-March 1999 and August 2008-July 2009) have been analysed for major sources by receptor modelling using Positive Matrix Factorisation (PMF). For the 2008/2009 period, it was found that secondary aerosols (sulphate- and nitrate-rich secondary aerosols, SSA and NSA) are the most abundant components of PM10 at sites north of the Alps. Road traffic and wood combustion were found to be the largest sources of PM10 at these sites. Except at the urban roadside site where road traffic is dominating (40% of PM10 -- including road salt), the annual average contribution of these two sources is of similar importance (17% and 14% of PM10, respectively). At a rural site south of the Alps wood combustion and road traffic contributions to PM10 were higher (31% and 24%, respectively), and the fraction of secondary aerosols lower (29%) than at similar site types north of the Alps. Comparison of PMF analyses for the two time periods (1998/1999 and 2008/2009) revealed decreasing average contributions of road traffic and SSA to PM10 at all sites. This indicates that the measures that were implemented in Switzerland and in neighbouring countries to reduce emissions of sulphur dioxide and PM10 from road traffic were successful. On the other hand, contributions of wood combustion did not change during this ten year period, and the contribution of nitrate-rich secondary aerosols has even increased. It is shown that PMF can be a helpful tool for the assessment of long-term changes of source contributions to ambient particulate matter.

Characterization of Off-Road Diesel Emissions of Criteria Pollutants

DTIC Science & Technology

2008-10-01

Feasibility of soil dust source apportionment by the pyrolysis-gas chromatography/mass spectrometry method. J. Air Waste Manage. Assoc., 56(9):1230-1242...temperatures found in exhaust pipes. PM2.5 source profiles are important for speciated emission inventories and source apportionment , but few of these are...different between types. This method holds great potential for source apportionment , even in the absence of associating each pattern with a specific

Advanced source apportionment of carbonaceous aerosols by coupling offline AMS and radiocarbon size-segregated measurements over a nearly 2-year period

NASA Astrophysics Data System (ADS)

Vlachou, Athanasia; Daellenbach, Kaspar R.; Bozzetti, Carlo; Chazeau, Benjamin; Salazar, Gary A.; Szidat, Soenke; Jaffrezo, Jean-Luc; Hueglin, Christoph; Baltensperger, Urs; El Haddad, Imad; Prévôt, André S. H.

2018-05-01

Carbonaceous aerosols are related to adverse human health effects. Therefore, identification of their sources and analysis of their chemical composition is important. The offline AMS (aerosol mass spectrometer) technique offers quantitative separation of organic aerosol (OA) factors which can be related to major OA sources, either primary or secondary. While primary OA can be more clearly separated into sources, secondary (SOA) source apportionment is more challenging because different sources - anthropogenic or natural, fossil or non-fossil - can yield similar highly oxygenated mass spectra. Radiocarbon measurements provide unequivocal separation between fossil and non-fossil sources of carbon. Here we coupled these two offline methods and analysed the OA and organic carbon (OC) of different size fractions (particulate matter below 10 and 2.5 µm - PM10 and PM2.5, respectively) from the Alpine valley of Magadino (Switzerland) during the years 2013 and 2014 (219 samples). The combination of the techniques gave further insight into the characteristics of secondary OC (SOC) which was rather based on the type of SOC precursor and not on the volatility or the oxidation state of OC, as typically considered. Out of the primary sources separated in this study, biomass burning OC was the dominant one in winter, with average concentrations of 5.36 ± 2.64 µg m-3 for PM10 and 3.83 ± 1.81 µg m-3 for PM2.5, indicating that wood combustion particles were predominantly generated in the fine mode. The additional information from the size-segregated measurements revealed a primary sulfur-containing factor, mainly fossil, detected in the coarse size fraction and related to non-exhaust traffic emissions with a yearly average PM10 (PM2.5) concentration of 0.20 ± 0.24 µg m-3 (0.05 ± 0.04 µg m-3). A primary biological OC (PBOC) was also detected in the coarse mode peaking in spring and summer with a yearly average PM10 (PM2.5) concentration of 0.79 ± 0.31 µg m-3 (0.24 ± 0.20 µg m-3). The secondary OC was separated into two oxygenated, non-fossil OC factors which were identified based on their seasonal variability (i.e. summer and winter oxygenated organic carbon, OOC) and a third anthropogenic OOC factor which correlated with fossil OC mainly peaking in winter and spring, contributing on average 13 % ± 7 % (10 % ± 9 %) to the total OC in PM10 (PM2.5). The winter OOC was also connected to anthropogenic sources, contributing on average 13 % ± 13 % (6 % ± 6 %) to the total OC in PM10 (PM2.5). The summer OOC (SOOC), stemming from oxidation of biogenic emissions, was more pronounced in the fine mode, contributing on average 43 % ± 12 % (75 % ± 44 %) to the total OC in PM10 (PM2.5). In total the non-fossil OC significantly dominated the fossil OC throughout all seasons, by contributing on average 75 % ± 24 % to the total OC. The results also suggested that during the cold period the prevailing source was residential biomass burning while during the warm period primary biological sources and secondary organic aerosol from the oxidation of biogenic emissions became important. However, SOC was also formed by aged fossil fuel combustion emissions not only in summer but also during the rest of the year.

Chemical characterization of fine particulate matter in Changzhou, China, and source apportionment with offline aerosol mass spectrometry

NASA Astrophysics Data System (ADS)

Ye, Zhaolian; Liu, Jiashu; Gu, Aijun; Feng, Feifei; Liu, Yuhai; Bi, Chenglu; Xu, Jianzhong; Li, Ling; Chen, Hui; Chen, Yanfang; Dai, Liang; Zhou, Quanfa; Ge, Xinlei

2017-02-01

Knowledge of aerosol chemistry in densely populated regions is critical for effective reduction of air pollution, while such studies have not been conducted in Changzhou, an important manufacturing base and populated city in the Yangtze River Delta (YRD), China. This work, for the first time, performed a thorough chemical characterization on the fine particulate matter (PM2.5) samples, collected during July 2015 to April 2016 across four seasons in this city. A suite of analytical techniques was employed to measure the organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble inorganic ions (WSIIs), trace elements, and polycyclic aromatic hydrocarbons (PAHs) in PM2.5; in particular, an Aerodyne soot particle aerosol mass spectrometer (SP-AMS) was deployed to probe the chemical properties of water-soluble organic aerosol (WSOA). The average PM2.5 concentration was found to be 108.3 µg m-3, and all identified species were able to reconstruct ˜ 80 % of the PM2.5 mass. The WSIIs occupied about half of the PM2.5 mass (˜ 52.1 %), with SO42-, NO3-, and NH4+ as the major ions. On average, nitrate concentrations dominated over sulfate (mass ratio of 1.21), indicating that traffic emissions were more important than stationary sources. OC and EC correlated well with each other and the highest OC / EC ratio (5.16) occurred in winter, suggesting complex OC sources likely including both secondary and primary ones. Concentrations of eight trace elements (Mn, Zn, Al, B, Cr, Cu, Fe, Pb) can contribute up to ˜ 5.0 % of PM2.5 during winter. PAH concentrations were also high in winter (140.25 ng m-3), which were predominated by median/high molecular weight PAHs with five and six rings. The organic matter including both water-soluble and water-insoluble species occupied ˜ 21.5 % of the PM2.5 mass. SP-AMS determined that the WSOA had average atomic oxygen-to-carbon (O / C), hydrogen-to-carbon (H / C), nitrogen-to-carbon (N / C), and organic matter-to-organic carbon (OM / OC) ratios of 0.54, 1.69, 0.11, and 1.99, respectively. Source apportionment of WSOA further identified two secondary OA (SOA) factors (a less oxidized and a more oxidized oxygenated OA) and two primary OA (POA) factors (a nitrogen-enriched hydrocarbon-like traffic OA and a local primary OA likely including species from cooking, coal combustion, etc.). On average, the POA contribution outweighed SOA (55 % vs. 45 %), indicating the important role of local anthropogenic emissions in the aerosol pollution in Changzhou. Our measurement also shows the abundance of organic nitrogen species in WSOA, and the source analyses suggest these species are likely associated with traffic emissions, which warrants more investigations on PM samples from other locations.

Source characterization of ambient fine aerosol in Singapore during a haze episode in 2015

NASA Astrophysics Data System (ADS)

Hapsari Budisulistiorini, Sri; Riva, Matthieu; Williams, Michael; Miyakawa, Takuma; Komazaki, Yuichi; Chen, Jing; Surratt, Jason; Kuwata, Mikinori

2017-04-01

Recurring transboundary haze from Indonesia peatland fires in the previous decades has significantly elevated particulate matter (PM) concentration in Southeast Asia, particularly during the 2015 El Niño event. Previous studies have investigated chemical composition of particles emitted during haze episodes; however, they were limited to time-integrated samples and the number of identified compounds. Low time-resolution measurement results in co-variance of PM sources; therefore, higher time-resolution measurement is important in PM source apportionment. Between October 10-31, 2015, Aerodyne Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) was deployed for real-time chemical characterization of ambient submicron PM (NR-PM1) in Singapore. Simultaneously, PM2.5 filter samples were collected for molecular-level organic aerosol (OA) constituents, organic carbon (OC), elemental carbon (EC) and water-soluble OC (WSOC) analyses. OA constituents were quantified by gas chromatography interfaced to electron ionization mass spectrometry (GC/EI-MS) and ultra-performance liquid chromatography interfaced to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer operated in the negative ion mode (UPLC/(-)ESI-HR-Q-TOFMS). OA and SO42- are dominant components of the haze particles, accounting for ˜77% and ˜12% of the total NR-PM1 mass, respectively. OC/EC ratio of 4.8 might indicate formation of secondary OA (SOA) and aerosols from biomass burning, including those from peat burning. OA fraction from ToF-ACSM measurements was analyzed for source apportionment using a bilinear model through multi-linear engine algorithm (ME-2) in graphical user interface SoFi (Source Finder). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), peat burning OA (PBOA), low-volatility oxygenated OA (LV-OOA), and semi-volatile oxygenated OA (SV-OOA). The HOA factor shows a distinct diurnal profile peaking in the morning and evening, suggesting traffic influences. The BBOA factor was identified based on factor profile of wood burning particles and correlated with known biomass burning tracers (i.e. levoglucosan and mannosan). The PBOA factor was identified based on factor profile of laboratory-generated peat burning particles. This factor would be further identified with OA constituents in peat burning particles, such as brown carbon constituents. The LV-OOA and SV-OOA factors peak in the afternoon indicating they were likely formed through photochemistry. The LV-OOA factor might be a product of biomass burning aerosol aging as indicated by temporal trend correlations with BBOA and PBOA factors (r2 = 0.7-0.8). Contributions of the HOA and SV-OOA factors to OA mass are ˜12% and ˜21%, respectively. The biomass burning-related factors (BBOA and PBOA) account for ˜29% of OA mass, which likely indicates a lower-bound estimate of the transboundary impacts of primary emissions from peatland fires. The transboundary impacts of secondary aerosol from peatland fires might be represented by the LV-OOA factor accounting for ˜37% of OA mass. Overall, the transboundary haze could contribute to ˜66% of OA concentration, suggesting the strong influence of Indonesia peatland fires on the air quality of Singapore.

Chemical characteristics and source apportionment of fine particulate organic carbon in Hong Kong during high particulate matter episodes in winter 2003

NASA Astrophysics Data System (ADS)

Li, Yun-Chun; Yu, Jian Zhen; Ho, Steven Sai Hang; Schauer, James J.; Yuan, Zibing; Lau, Alexis K. H.; Louie, Peter K. K.

2013-02-01

PM2.5 samples were collected at six general stations and one roadside station in Hong Kong in two periods of high particulate matter (PM) in 2003 (27 October-4 November and 30 November-13 December). The highest PM2.5 reached 216 μg m- 3 during the first high PM period and 113 μg m- 3 during the second high PM period. Analysis of synoptic weather conditions identified individual sampling days under dominant influence of one of three types of air masses, that is, local, regional and long-range transported (LRT) air masses. Roadside samples were discussed separately due to heavy influences from vehicular emissions. This research examines source apportionment of fine organic carbon (OC) and contribution of secondary organic aerosol on high PM days under different synoptic conditions. Six primary OC (POC) sources (vehicle exhaust, biomass burning, cooking, cigarette smoke, vegetative detritus, and coal combustion) were identified on the basis of characteristic organic tracers. Individual POC source contributions were estimated using chemical mass balance model. In the roadside and the local samples, OC was dominated by the primary sources, accounting for more than 74% of OC. In the samples influenced by regional and LRT air masses, secondary OC (SOC), which was approximated to be the difference between the total measured OC and the apportioned POC, contributed more than 54% of fine OC. SOC was highly correlated with water-soluble organic carbon and sulfate, consistent with its secondary nature.

Trends and sources for heavy metals in urban atmosphere

NASA Astrophysics Data System (ADS)

Kemp, Kåre

2002-04-01

The concentrations of a number of heavy metals in the air in three Danish cities have been measured by means of PIXE for more than two decades. The well-known capability of PIXE for fast and efficient analysis of aerosol samples has been employed for analysis of daily samples from several sites during the whole period. The main sources are traffic, domestic heating and long-range transport. Source apportionment and trends for single metals are assessed by means of simple statistical methods. The most striking change has occurred for the Pb concentration, which is reduced by almost a factor of 100 following the reduction of the Pb content in petrol. The main source of Cu, Cr and Zn is the traffic. The concentrations of these elements have been slightly increasing. The concentrations for most of the other heavy metals, which originate mainly from sources outside the cities, have been decreasing.

Diurnal and seasonal trends and source apportionment of redox-active metals in Los Angeles using a novel online metal monitor and Positive Matrix Factorization (PMF)

NASA Astrophysics Data System (ADS)

Mousavi, Amirhosein; Sowlat, Mohammad H.; Sioutas, Constantinos

2018-02-01

In the present study, we identified the sources of four redox-active metals, including Iron (Fe), Chromium (Cr), Cupper (Cu), and Manganese (Mn) and quantified the contribution of these sources to PM2.5 concentrations in central Los Angeles, California, by employing time-resolved measurements (i.e., a time resolution of 2 h) with a recently developed online metal monitor and Positive Matrix Factorization (PMF). Size distribution of ambient PM (14 nm-10 μm) was measured using the Scanning Mobility Particle Sizer (SMPS) and Optical Particle Sizer (OPS). Auxiliary variables were also collected, including elemental (EC) and organic carbon (OC), gaseous pollutants (NO2 and O3), meteorological parameters (including relative humidity (RH) and temperature), and traffic data (for heavy- (HDVs) and light-duty vehicles (LDVs)). A 4-factor solution was found to be optimum for the chemically-speciated dataset, whereas a 5-factor solution appeared to be most plausible for the size distribution data. The factors included fresh traffic, soil/road dust, urban background aerosol, secondary aerosol, and nucleation (only resolved for the size distribution data). Fresh traffic was the major contributor to Fe and Cu concentrations, whereas Cr was mostly found in the urban background aerosol (reflecting a mixture of small local sources as well as aged traffic emissions), and Mn mostly came from both soil/road dust and was to a lesser degree found in urban background aerosol. Secondary aerosol did not contribute to the concentrations of any of these metals, but was associated with very high loading of OC, as expected. Even though the urban background aerosol and secondary aerosol appeared to be characterized by "aged" particles and have a rather homogeneous spatial distribution, the reactions and processes involved in their formation are entirely different. Our results provide insights into the sources of redox-active metals in central Los Angeles. They also underscore the benefits of novel measurement techniques for PM-bound metals, which could enhance our understanding of the sources of atmospheric aerosols by providing us with measurements with finer time resolutions that otherwise would not have been possible using traditional filter-based measurement techniques.

Enhancing non-refractory aerosol apportionment from an urban industrial site through receptor modeling of complete high time-resolution aerosol mass spectra

NASA Astrophysics Data System (ADS)

McGuire, M. L.; Chang, R. Y.-W.; Slowik, J. G.; Jeong, C.-H.; Healy, R. M.; Lu, G.; Mihele, C.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

2014-08-01

Receptor modeling was performed on quadrupole unit mass resolution aerosol mass spectrometer (Q-AMS) sub-micron particulate matter (PM) chemical speciation measurements from Windsor, Ontario, an industrial city situated across the Detroit River from Detroit, Michigan. Aerosol and trace gas measurements were collected on board Environment Canada's Canadian Regional and Urban Investigation System for Environmental Research (CRUISER) mobile laboratory. Positive matrix factorization (PMF) was performed on the AMS full particle-phase mass spectrum (PMFFull MS) encompassing both organic and inorganic components. This approach compared to the more common method of analyzing only the organic mass spectra (PMFOrg MS). PMF of the full mass spectrum revealed that variability in the non-refractory sub-micron aerosol concentration and composition was best explained by six factors: an amine-containing factor (Amine); an ammonium sulfate- and oxygenated organic aerosol-containing factor (Sulfate-OA); an ammonium nitrate- and oxygenated organic aerosol-containing factor (Nitrate-OA); an ammonium chloride-containing factor (Chloride); a hydrocarbon-like organic aerosol (HOA) factor; and a moderately oxygenated organic aerosol factor (OOA). PMF of the organic mass spectrum revealed three factors of similar composition to some of those revealed through PMFFull MS: Amine, HOA and OOA. Including both the inorganic and organic mass proved to be a beneficial approach to analyzing the unit mass resolution AMS data for several reasons. First, it provided a method for potentially calculating more accurate sub-micron PM mass concentrations, particularly when unusual factors are present, in this case the Amine factor. As this method does not rely on a priori knowledge of chemical species, it circumvents the need for any adjustments to the traditional AMS species fragmentation patterns to account for atypical species, and can thus lead to more complete factor profiles. It is expected that this method would be even more useful for HR-ToF-AMS data, due to the ability to understand better the chemical nature of atypical factors from high-resolution mass spectra. Second, utilizing PMF to extract factors containing inorganic species allowed for the determination of the extent of neutralization, which could have implications for aerosol parameterization. Third, subtler differences in organic aerosol components were resolved through the incorporation of inorganic mass into the PMF matrix. The additional temporal features provided by the inorganic aerosol components allowed for the resolution of more types of oxygenated organic aerosol than could be reliably resolved from PMF of organics alone. Comparison of findings from the PMFFull MS and PMFOrg MS methods showed that for the Windsor airshed, the PMFFull MS method enabled additional conclusions to be drawn in terms of aerosol sources and chemical processes. While performing PMFOrg MS can provide important distinctions between types of organic aerosol, it is shown that including inorganic species in the PMF analysis can permit further apportionment of organics for unit mass resolution AMS mass spectra.

Enhancing non-refractory aerosol apportionment from an urban industrial site through receptor modelling of complete high time-resolution aerosol mass spectra

NASA Astrophysics Data System (ADS)

McGuire, M. L.; Chang, R. Y.-W.; Slowik, J. G.; Jeong, C.-H.; Healy, R. M.; Lu, G.; Mihele, C.; Abbatt, J. P. D.; Brook, J. R.; Evans, G. J.

2014-02-01

Receptor modelling was performed on quadrupole unit mass resolution aerosol mass spectrometer (Q-AMS) sub-micron particulate matter (PM) chemical speciation measurements from Windsor, Ontario, an industrial city situated across the Detroit River from Detroit, Michigan. Aerosol and trace gas measurements were collected on board Environment Canada's CRUISER mobile laboratory. Positive matrix factorization (PMF) was performed on the AMS full particle-phase mass spectrum (PMFFull MS) encompassing both organic and inorganic components. This approach was compared to the more common method of analysing only the organic mass spectra (PMFOrg MS). PMF of the full mass spectrum revealed that variability in the non-refractory sub-micron aerosol concentration and composition was best explained by six factors: an amine-containing factor (Amine); an ammonium sulphate and oxygenated organic aerosol containing factor (Sulphate-OA); an ammonium nitrate and oxygenated organic aerosol containing factor (Nitrate-OA); an ammonium chloride containing factor (Chloride); a hydrocarbon-like organic aerosol (HOA) factor; and a moderately oxygenated organic aerosol factor (OOA). PMF of the organic mass spectrum revealed three factors of similar composition to some of those revealed through PMFFull MS: Amine, HOA and OOA. Including both the inorganic and organic mass proved to be a beneficial approach to analysing the unit mass resolution AMS data for several reasons. First, it provided a method for potentially calculating more accurate sub-micron PM mass concentrations, particularly when unusual factors are present, in this case, an Amine factor. As this method does not rely on a priori knowledge of chemical species, it circumvents the need for any adjustments to the traditional AMS species fragmentation patterns to account for atypical species, and can thus lead to more complete factor profiles. It is expected that this method would be even more useful for HR-ToF-AMS data, due to the ability to better understand the chemical nature of atypical factors from high resolution mass spectra. Second, utilizing PMF to extract factors containing inorganic species allowed for the determination of extent of neutralization, which could have implications for aerosol parameterization. Third, subtler differences in organic aerosol components were resolved through the incorporation of inorganic mass into the PMF matrix. The additional temporal features provided by the inorganic aerosol components allowed for the resolution of more types of oxygenated organic aerosol than could be reliably resolved from PMF of organics alone. Comparison of findings from the PMFFull MS and PMFOrg MS methods showed that for the Windsor airshed, the PMFFull MS method enabled additional conclusions to be drawn in terms of aerosol sources and chemical processes. While performing PMFOrg MS can provide important distinctions between types of organic aerosol, it is shown that including inorganic species in the PMF analysis can permit further apportionment of organics for unit mass resolution AMS mass spectra.

Physico-chemical characterization of Mediterranean background aerosol at the Capogranitola observatory (Sicily)

NASA Astrophysics Data System (ADS)

Rinaldi, Matteo; Gilardoni, Stefania; Paglione, Marco; Sandrini, Silvia; Decesari, Stefano; Zanca, Nicola; Marinoni, Angela; Cristofanelli, Paolo; Bonasoni, Paolo; Ielpo, Piera; Fossum, Kirsten; Gobbi, Gian Paolo; Facchini, Maria Cristina

2017-04-01

The Mediterranean basin is characterized by elevated aerosol amounts and co-existence of different aerosol types, both natural and anthropogenic, while it is one of the most climatically sensitive areas. Therefore, it offers ideal conditions for studying aerosol processes and aerosol-climate interactions. An intensive aerosol physico-chemical characterization campaign was held at the Environmental-Climatic Observatory at Capo Granitola (Sicily; 37.5753° N, 12.6595° E) during April 2016, under the framework of the project Air-Sea Lab. The Observatory is located at the coast-line, facing the Strait of Sicily, and is part of the national I-AMICA network (http://www.i-amica.it/i-amica/?lang=en). Sub-micrometer aerosol chemical composition was measured by high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS), for the first time at Capogranitola. Sea-salt concentration was estimated from AMS measurements following Ovadnevaite et al. (2012). For a complete mass closure of the submicron aerosol, black carbon (BC) concentration was derived from multiangle absorption photometer (MAAP) measurements. Positive matrix factorization was deployed to investigate organic aerosol (OA) sources at the site. Aerosol chemical composition confirms that Capogranitola is a representative background site, with generally low contribution of BC and nitrate and highly oxidized OA. In particular, aerosol sampled in the marine sector (130-310°) is less affected by local sources and it is likely representative of the central Mediterranean background. Aerosol in background conditions is dominated by sulfate and OA (37% and 31%), followed by ammonium (12%), sea-salt (10%), BC (6%) and nitrate (3%). The average reconstructed sub-micrometer aerosol mass in background conditions is 3.7±2.3 μg m-3. OA source apportionment shows a minor contribution from primary sources, with hydrocarbon-like OA (HOA), from fossil fuel combustion, contributing for 3% and biomass burning OA (BBOA) for 2%. Oxidized OA (OOA) dominates the rest of OA mass. In particular, OOA1 and OOA2 (70% in total, OM:OC ˜ 2.5) represent the result of prolonged atmospheric processing of OA, while OOA3 (25%, OM:OC ˜ 2.0) clearly represents fresher inputs of OOA from land. Investigation of HOA and BC time trends suggests that HOA in background conditions may be strongly contributed by ship traffic more than by land sources. The representativity of the background aerosol collected at Capogranitola will be discussed by comparing with measurements performed in parallel at the other I-AMICA southern Italy coastal stations and with those acquired in a subsequent cruise (May-June 2016) around the Italian Peninsula. Aerosol climate relevant properties, in relation with chemical composition, will be also presented and discussed. Ovadnevaite J. et al. (2012), J. Geophys. Res., 117, D16201.

Source apportionment and sensitivity analysis: two methodologies with two different purposes

NASA Astrophysics Data System (ADS)

Clappier, Alain; Belis, Claudio A.; Pernigotti, Denise; Thunis, Philippe

2017-11-01

This work reviews the existing methodologies for source apportionment and sensitivity analysis to identify key differences and stress their implicit limitations. The emphasis is laid on the differences between source impacts (sensitivity analysis) and contributions (source apportionment) obtained by using four different methodologies: brute-force top-down, brute-force bottom-up, tagged species and decoupled direct method (DDM). A simple theoretical example to compare these approaches is used highlighting differences and potential implications for policy. When the relationships between concentration and emissions are linear, impacts and contributions are equivalent concepts. In this case, source apportionment and sensitivity analysis may be used indifferently for both air quality planning purposes and quantifying source contributions. However, this study demonstrates that when the relationship between emissions and concentrations is nonlinear, sensitivity approaches are not suitable to retrieve source contributions and source apportionment methods are not appropriate to evaluate the impact of abatement strategies. A quantification of the potential nonlinearities should therefore be the first step prior to source apportionment or planning applications, to prevent any limitations in their use. When nonlinearity is mild, these limitations may, however, be acceptable in the context of the other uncertainties inherent to complex models. Moreover, when using sensitivity analysis for planning, it is important to note that, under nonlinear circumstances, the calculated impacts will only provide information for the exact conditions (e.g. emission reduction share) that are simulated.

Source Apportionment of PM2.5 Mass and Optical Attenuation Over an Ecologically Sensitive Zone in Central India by Positive Matrix Factorization

NASA Astrophysics Data System (ADS)

Nirmalkar, J.; Raman, R. S.

2016-12-01

Ambient PM2.5 samples (N=366) were collected over an ecologically sensitive zone (Van Vihar National Park) in Bhopal, Central India for two years (01 January, 2012 to 31 December, 2013). Samples were collected using three co-located Mini-Vol® samplers on Teflon, Nylon, and Quartz filter substrates. The aerosol was then chemically characterized for water-soluble inorganic ions, elements, and carbon fractions (elemental carbon and organic carbon) using ion chromatography, ED-XRF, and thermal-optical EC/OC analyzer, respectively. The optical attenuation (at 370 nm and 800 nm) of PM2.5 aerosols was also determined by optical transmissometry (OT-21). The application of Positive matrix factorization (PMF) to a combination of PM2.5 mass, its ions, elements, carbon fractions, and optical attenuation and its outcomes will be discussed.

Investigating the contribution of shipping emissions to atmospheric PM2.5 using a combined source apportionment approach.

PubMed

Lang, Jianlei; Zhou, Ying; Chen, Dongsheng; Xing, Xiaofan; Wei, Lin; Wang, Xiaotong; Zhao, Na; Zhang, Yanyun; Guo, Xiurui; Han, Lihui; Cheng, Shuiyuan

2017-10-01

Many studies have been conducted focusing on the contribution of land emission sources to PM 2.5 in China; however, little attention had been paid to other contributions, especially the secondary contributions from shipping emissions to atmospheric PM 2.5 . In this study, a combined source apportionment approach, including principle component analysis (PCA) and WRF-CMAQ simulation, was applied to identify both primary and secondary contributions from ships to atmospheric PM 2.5 . An intensive PM 2.5 observation was conducted from April 2014 to January 2015 in Qinhuangdao, which was close to the largest energy output port of China. The chemical components analysis results showed that the primary component was the major contributor to PM 2.5 , with proportions of 48.3%, 48.9%, 55.1% and 55.4% in spring, summer, autumn and winter, respectively. The secondary component contributed higher fractions in summer (48.2%) and winter (36.8%), but had lower percentages in spring (30.1%) and autumn (32.7%). The hybrid source apportionment results indicated that the secondary contribution (SC) of shipping emissions to PM 2.5 could not be ignored. The annual average SC was 2.7%, which was comparable to the primary contribution (2.9%). The SC was higher in summer (5.3%), but lower in winter (1.1%). The primary contributions to atmospheric PM 2.5 were 3.0%, 2.5%, 3.4% and 2.7% in spring, summer, autumn and winter, respectively. As for the detailed chemical components, the contributions of shipping emissions were 2.3%, 0.5%, 0.1%, 1.0%, 1.7% and 0.1% to elements & sea salt, primary organic aerosol (POA), element carbon (EC), nitrate, sulfate and secondary organic carbon (SOA), respectively. The results of this study will further the understanding of the implications of shipping emissions in PM 2.5 pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Source apportionment of aerosol particles at a European air pollution hot spot using particle number size distributions and chemical composition.

PubMed

Leoni, Cecilia; Pokorná, Petra; Hovorka, Jan; Masiol, Mauro; Topinka, Jan; Zhao, Yongjing; Křůmal, Kamil; Cliff, Steven; Mikuška, Pavel; Hopke, Philip K

2018-03-01

Ostrava in the Moravian-Silesian region (Czech Republic) is a European air pollution hot spot for airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and ultrafine particles (UFPs). Air pollution source apportionment is essential for implementation of successful abatement strategies. UFPs or nanoparticles of diameter <100 nm exhibit the highest deposition efficiency in human lungs. To permit apportionment of PM sources at the hot-spot including nanoparticles, Positive Matrix Factorization (PMF) was applied to highly time resolved particle number size distributions (NSD, 14 nm-10 μm) and PM 0.09-1.15 chemical composition. Diurnal patterns, meteorological variables, gaseous pollutants, organic markers, and associations between the NSD factors and chemical composition factors were used to identify the pollution sources. The PMF on the NSD reveals two factors in the ultrafine size range: industrial UFPs (28%, number mode diameter - NMD 45 nm), industrial/fresh road traffic nanoparticles (26%, NMD 26 nm); three factors in the accumulation size range: urban background (24%, NMD 93 nm), coal burning (14%, volume mode diameter - VMD 0.5 μm), regional pollution (3%, VMD 0.8 μm) and one factor in the coarse size range: industrial coarse particles/road dust (2%, VMD 5 μm). The PMF analysis of PM 0.09-1.15 revealed four factors: SIA/CC/BB (52%), road dust (18%), sinter/steel (16%), iron production (16%). The factors in the ultrafine size range resolved with NSD have a positive correlation with sinter/steel production and iron production factors resolved with chemical composition. Coal combustion factor resolved with NSD has moderate correlation with SIA/CC/BB factor. The organic markers homohopanes correlate with coal combustion and the levoglucosan correlates with urban background. The PMF applications to NSD and chemical composition datasets are complementary. PAHs in PM 1 were found to be associated with coal combustion factor. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photochemical grid model implementation and application of ...

EPA Pesticide Factsheets

For the purposes of developing optimal emissions control strategies, efficient approaches are needed to identify the major sources or groups of sources that contribute to elevated ozone (O3) concentrations. Source-based apportionment techniques implemented in photochemical grid models track sources through the physical and chemical processes important to the formation and transport of air pollutants. Photochemical model source apportionment has been used to track source impacts of specific sources, groups of sources (sectors), sources in specific geographic areas, and stratospheric and lateral boundary inflow on O3. The implementation and application of a source apportionment technique for O3 and its precursors, nitrogen oxides (NOx) and volatile organic compounds (VOCs), for the Community Multiscale Air Quality (CMAQ) model are described here. The Integrated Source Apportionment Method (ISAM) O3 approach is a hybrid of source apportionment and source sensitivity in that O3 production is attributed to precursor sources based on O3 formation regime (e.g., for a NOx-sensitive regime, O3 is apportioned to participating NOx emissions). This implementation is illustrated by tracking multiple emissions source sectors and lateral boundary inflow. NOx, VOC, and O3 attribution to tracked sectors in the application are consistent with spatial and temporal patterns of precursor emissions. The O3 ISAM implementation is further evaluated through comparisons of apportioned am

Fine Mode Aerosol over the United Arab Emirates

NASA Astrophysics Data System (ADS)

Ross, K. E.; Piketh, S. J.; Reid, J. S.; Reid, E. A.

2005-12-01

The aerosol loading of the atmosphere over the Arabian Gulf region is extremely diverse and is composed not only of dust, but also of pollution that is derived largely from oil-related activities. Fine mode pollution particles are most efficient at scattering incoming solar radiation and have the potential to act as cloud condensation nuclei (CCN), and may therefore have implications for climate change. The smaller aerosols may also pose a health hazard if present in high concentrations. The United Arab Emirates Unified Aerosol Experiment (UAE2) was designed to investigate aerosol and meteorological characteristics over the region using ground-based, aircraft and satellite measurements, and was conducted in August and September 2004. Aerosol chemical composition has been obtained from filters that were collected at the site of the Mobile Atmospheric Aerosol and Radiation Characterization Observatory (MAARCO) on the coast of the UAE between Abu Dhabi and Dubai. Filter samples were also collected on an airborne platform in order to assess how aerosol chemical composition varies across the region and throughout the depth of the boundary layer. Results of the analysis of the PM2.5 coastal samples show that ammonium sulphate is the most prevalent constituent of the fine mode aerosol in the region (>50% of the mass), followed by organic matter, alumino-silicates, calcium carbonate and black carbon. Source apportionment indicates that most of the fine aerosol mass is derived from fossil fuel combustion, while mineral dust and local vehicle emissions also contribute to the fine aerosol loading. The organic carbon-to-total carbon ratio of the aerosol is 0.65, which is typical of fossil fuel combustion. The dominance of sulphates means that the fine mode aerosol in the region is probably responsible for a negative radiative forcing, and that the polluting emissions significantly elevate the concentration of CCN.

Spatial and Temporal Variations of Aerosols Around Beijing in the Summer 2006: Model Evaluation and Source Apportionment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsui, Hitoshi; Koike, Makoto; Kondo, Yutaka

Regional aerosol model calculations were made using the WRF-CMAQ and WRF-chem models to study spatial and temporal variations of aerosols around Beijing, China, in August and September 2006 when the CAREBEIJING-2006 campaign was conducted. Model calculations were compared with in-situ observations made at the urban site in Beijing and suburb site in Yufa, which is 50 km to the south of Beijing. In general, the two model calculations reproduced features of temporal variations of meteorological parameters and concentrations of elemental carbon (EC) and inorganic aerosols (sulfate, ammonium, and nitrate). Spatial distributions of aerosol optical depth (AOD) obtained by the MODISmore » satellite sensor are also generally well reproduced. Model calculations show that enhancements in inorganic aerosol concentrations simultaneously observed at the two sites 4 to 5 times during the one-month observation period were resulted by accumulation of pollutants under stagnated air condition. Because Beijing is located at the north border the high anthropogenic emission area (the Great North China Plain), northward motion of air under the influence of anti-cyclone system caused enhancements in fine aerosol concentrations at Beijing. Concentrations of primary aerosols, such as EC, are found to be generally controlled by emissions within 100 km around Beijing within previous 24 hours. On the other hand, emissions as far as 500 km within previous 3 days were found to affect concentrations of secondary aerosols, such as sulfate. Because of significant contributions of secondary aerosols in Beijing, regional emission controls are found to be necessary for improvement of air quality in Beijing.« less

Measurements of the aerosol chemical composition and mixing state in the Po Valley using multiple spectroscopic techniques

NASA Astrophysics Data System (ADS)

Decesari, S.; Allan, J.; Plass-Duelmer, C.; Williams, B. J.; Paglione, M.; Facchini, M. C.; O'Dowd, C.; Harrison, R. M.; Gietl, J. K.; Coe, H.; Giulianelli, L.; Gobbi, G. P.; Lanconelli, C.; Carbone, C.; Worsnop, D.; Lambe, A. T.; Ahern, A. T.; Moretti, F.; Tagliavini, E.; Elste, T.; Gilge, S.; Zhang, Y.; Dall'Osto, M.

2014-11-01

The use of co-located multiple spectroscopic techniques can provide detailed information on the atmospheric processes regulating aerosol chemical composition and mixing state. So far, field campaigns heavily equipped with aerosol mass spectrometers have been carried out mainly in large conurbations and in areas directly affected by their outflow, whereas lesser efforts have been dedicated to continental areas characterised by a less dense urbanisation. We present here the results obtained at a background site in the Po Valley, Italy, in summer 2009. For the first time in Europe, six state-of-the-art spectrometric techniques were used in parallel: aerosol time-of-flight mass spectrometer (ATOFMS), two aerosol mass spectrometers (high-resolution time-of-flight aerosol mass spectrometer - HR-ToF-AMS and soot particle aerosol mass spectrometer - SP-AMS), thermal desorption aerosol gas chromatography (TAG), chemical ionisation mass spectrometry (CIMS) and (offline) proton nuclear magnetic resonance (1H-NMR) spectroscopy. The results indicate that, under high-pressure conditions, atmospheric stratification at night and early morning hours led to the accumulation of aerosols produced by anthropogenic sources distributed over the Po Valley plain. Such aerosols include primary components such as black carbon (BC), secondary semivolatile compounds such as ammonium nitrate and amines and a class of monocarboxylic acids which correspond to the AMS cooking organic aerosol (COA) already identified in urban areas. In daytime, the entrainment of aged air masses in the mixing layer is responsible for the accumulation of low-volatility oxygenated organic aerosol (LV-OOA) and also for the recycling of non-volatile primary species such as black carbon. According to organic aerosol source apportionment, anthropogenic aerosols accumulating in the lower layers overnight accounted for 38% of organic aerosol mass on average, another 21% was accounted for by aerosols recirculated in residual layers but still originating in northern Italy, while a substantial fraction (41%) was due to the most aged aerosols imported from transalpine areas. The different meteorological regimes also affected the BC mixing state: in periods of enhanced stagnation and recirculation of pollutants, the number fraction of the BC-containing particles determined by ATOFMS was 75% of the total, while in the days of enhanced ventilation of the planetary boundary layer (PBL), such fraction was significantly lower (50%) because of the relative greater influence of non-BC-containing aerosol local sources in the Po Valley. Overall, a full internal mixing between BC and the non-refractory aerosol chemical components was not observed during the experiment in this environment.

PM₁₀ and PM₂.₅ sources at an insular location in the western Mediterranean by using source apportionment techniques.

PubMed

Pey, Jorge; Alastuey, Andrés; Querol, Xavier

2013-07-01

PM₁₀ and PM₂.₅ chemical composition has been determined at a suburban insular site in the Balearic Islands (Spain) during almost one and a half year. As a result, 200 samples with more than 50 chemical parameters analyzed have been obtained. The whole database has been analyzed by two receptor modelling techniques (Principal Component Analysis and Positive Matrix Factorisation) in order to identify the main PM sources. After that, regression analyses with respect to the PM mass concentrations were conducted to quantify the daily contributions of each source. Four common sources were identified by both receptor models: secondary nitrate coupled with vehicular emissions, secondary sulphate influenced by fuel-oil combustion, aged marine aerosols and mineral dust. In addition, PCA isolated harbour emissions and a mixed anthropogenic factor containing industrial emissions; whereas PMF isolated an additional mineral factor interpreted as road dust+harbour emissions, and a vehicular abrasion products factor. The use of both methodologies appeared complementary. Nevertheless, PMF sources by themselves were better differentiated. Besides these receptor models, a specific methodology to quantify African dust was also applied. The combination of these three source apportionment tools allowed the identification of 8 sources, being 4 of them mineral (African, regional, urban and harbour dusts). As a summary, 29% of PM₁₀ was attributed to natural sources (African dust, regional dust and sea spray), whereas the proportion diminished to 11% in PM₂.₅. Furthermore, the secondary sulphate source, which accounted for about 22 and 32% of PM₁₀ and PM₂.₅, is strongly linked to the aged polluted air masses residing over the western Mediterranean in the warm period. Copyright © 2013 Elsevier B.V. All rights reserved.

Source apportionment of indoor air pollution

NASA Astrophysics Data System (ADS)

Sexton, Ken; Hayward, Steven B.

An understanding of the relative contributions from important pollutant sources to human exposures is necessary for the design and implementation of effective control strategies. In the past, societal efforts to control air pollution have focused almost exclusively on the outdoor (ambient) environment. As a result, substantial amounts of time and money have been spent to limit airborne discharges from mobile and stationary sources. Yet it is now recognized that exposures to elevated pollutant concentrations often occur as a result of indoor, rather than outdoor, emissions. While the major indoor sources have been identified, their relative impacts on indoor air quality have not been well defined. Application of existing source apportionment models to nonindustrial indoor environments is only just beginning. It is possible that these models might be used to distinguish between indoor and outdoor emissions, as well as to distinguish among indoor sources themselves. However, before the feasibility and suitability of source-apportionment methods for indoor applications can be assessed adequately, it is necessary to take account of model assumptions and associated data requirements. This paper examines the issue of indoor source apportionment and reviews the need for emission characterization studies to support such source-apportionment efforts.

Quantifying the effect of organic aerosol aging and intermediate-volatility emissions on regional-scale aerosol pollution in China

PubMed Central

Zhao, Bin; Wang, Shuxiao; Donahue, Neil M.; Jathar, Shantanu H.; Huang, Xiaofeng; Wu, Wenjing; Hao, Jiming; Robinson, Allen L.

2016-01-01

Secondary organic aerosol (SOA) is one of the least understood constituents of fine particles; current widely-used models cannot predict its loadings or oxidation state. Recent laboratory experiments demonstrated the importance of several new processes, including aging of SOA from traditional precursors, aging of primary organic aerosol (POA), and photo-oxidation of intermediate volatility organic compounds (IVOCs). However, evaluating the effect of these processes in the real atmosphere is challenging. Most models used in previous studies are over-simplified and some key reaction trajectories are not captured, and model parameters are usually phenomenological and lack experimental constraints. Here we comprehensively assess the effect of organic aerosol (OA) aging and intermediate-volatility emissions on regional-scale OA pollution with a state-of-the-art model framework and experimentally constrained parameters. We find that OA aging and intermediate-volatility emissions together increase OA and SOA concentrations in Eastern China by about 40% and a factor of 10, respectively, thereby improving model-measurement agreement significantly. POA and IVOCs both constitute over 40% of OA concentrations, and IVOCs constitute over half of SOA concentrations; this differs significantly from previous apportionment of SOA sources. This study facilitates an improved estimate of aerosol-induced climate and health impacts, and implies a shift from current fine-particle control policies. PMID:27350423

Source apportionment of organic aerosol across Houston, TX during DISCOVER-AQ

NASA Astrophysics Data System (ADS)

Yoon, S.; Clark, A. E.; Ortiz, S. M.; Usenko, S.; Sheesley, R. J.

2015-12-01

As part of the ground-based sampling efforts during DISCOVER-AQ's Houston month-long campaign in September 2013, atmospheric particulate matter (PM) samples were collected at four sites: Moody Tower (urban), Manvel Croix (southern suburb), Conroe (northern suburb), and La Porte (urban industrial). The Houston metropolitan area, especially the Houston Ship Channel, is a densely industrialized urban city with large concentrations of petroleum refining, petrochemical manufacturing, and heavy traffic during peak hours. Due to these and other emission sources, the area is heavily impacted by ambient PM. This study will be looking at fine PM (diameter less than 2.5µm, PM2.5) from all four sites. PM2.5fraction is relevant for understanding fate and transport of organic contaminants and is widely known to negatively impact human health. Chemical analysis including radiocarbon (14C) and organic tracer measurements (polycyclic aromatic hydrocarbons, alkanes, hopanes, steranes, and levoglucosan) were used for source apportionment. The 14C measurements constrained CMB results to estimate both primary and secondary contributions to total organic carbon (TOC). Results indicate that Moody Tower had consistent primary motor vehicle exhaust contribution (18-27%) and a fossil secondary organic aerosol (SOA) contribution from 5-33% depending on atmospheric conditions. Conroe had a lower contribution of motor vehicle exhaust (5-10%) and similarly variable fraction of fossil SOA (4-25%). Manvel Croix had an interim motor vehicle contribution (9-15%) with a variable fossil SOA (5-30%). For contemporary OC, there was minimal contribution of wood smoke during examined weeks (0-9%) but larger contributor of biogenic SOA ranging from 40-75% at Moody Tower, 56-81% at Manvel Croix and 60-79% at Conroe. Overall, the motor vehicle contribution was consistent at each site during the analysis week, biogenic SOA was consistently high, while fossil SOA showed the most variability.

Sophisticated Clean Air Strategies Required to Mitigate Against Particulate Organic Pollution

NASA Astrophysics Data System (ADS)

Grigas, T.; Ovadnevaite, J.; Ceburnis, D.; Moran, E.; McGovern, F. M.; Jennings, S. G.; O'Dowd, C.

2017-03-01

Since the 1980’s, measures mitigating the impact of transboundary air pollution have been implemented successfully as evidenced in the 1980-2014 record of atmospheric sulphur pollution over the NE-Atlantic, a key region for monitoring background northern-hemisphere pollution levels. The record reveals a 72-79% reduction in annual-average airborne sulphur pollution (SO4 and SO2, respectively) over the 35-year period. The NE-Atlantic, as observed from the Mace Head research station on the Irish coast, can be considered clean for 64% of the time during which sulphate dominates PM1 levels, contributing 42% of the mass, and for the remainder of the time, under polluted conditions, a carbonaceous (organic matter and Black Carbon) aerosol prevails, contributing 60% to 90% of the PM1 mass and exhibiting a trend whereby its contribution increases with increasing pollution levels. The carbonaceous aerosol is known to be diverse in source and nature and requires sophisticated air pollution policies underpinned by sophisticated characterisation and source apportionment capabilities to inform selective emissions-reduction strategies. Inauspiciously, however, this carbonaceous concoction is not measured in regulatory Air Quality networks.

Sophisticated Clean Air Strategies Required to Mitigate Against Particulate Organic Pollution.

PubMed

Grigas, T; Ovadnevaite, J; Ceburnis, D; Moran, E; McGovern, F M; Jennings, S G; O'Dowd, C

2017-03-17

Since the 1980's, measures mitigating the impact of transboundary air pollution have been implemented successfully as evidenced in the 1980-2014 record of atmospheric sulphur pollution over the NE-Atlantic, a key region for monitoring background northern-hemisphere pollution levels. The record reveals a 72-79% reduction in annual-average airborne sulphur pollution (SO 4 and SO 2 , respectively) over the 35-year period. The NE-Atlantic, as observed from the Mace Head research station on the Irish coast, can be considered clean for 64% of the time during which sulphate dominates PM 1 levels, contributing 42% of the mass, and for the remainder of the time, under polluted conditions, a carbonaceous (organic matter and Black Carbon) aerosol prevails, contributing 60% to 90% of the PM 1 mass and exhibiting a trend whereby its contribution increases with increasing pollution levels. The carbonaceous aerosol is known to be diverse in source and nature and requires sophisticated air pollution policies underpinned by sophisticated characterisation and source apportionment capabilities to inform selective emissions-reduction strategies. Inauspiciously, however, this carbonaceous concoction is not measured in regulatory Air Quality networks.

Positive matrix factorization of PM2.5 - eliminating the effects of gas/particle partitioning of semivolatile organic compounds.

PubMed

Xie, M; Barsanti, K C; Hannigan, M P; Dutton, S J; Vedal, S

2013-01-01

Gas-phase concentrations of semi-volatile organic compounds (SVOCs) were calculated from gas/particle (G/P) partitioning theory using their measured particle-phase concentrations. The particle-phase data were obtained from an existing filter measurement campaign (27 January 2003-2 October 2005) as a part of the Denver Aerosol Sources and Health (DASH) study, including 970 observations of 71 SVOCs (Xie et al., 2013). In each compound class of SVOCs, the lighter species (e.g. docosane in n alkanes, fluoranthene in PAHs) had higher total concentrations (gas + particle phase) and lower particle-phase fractions. The total SVOC concentrations were analyzed using positive matrix factorization (PMF). Then the results were compared with source apportionment results where only particle-phase SVOC concentrations were used (particle only-based study; Xie et al., 2013). For the particle only-based PMF analysis, the factors primarily associated with primary or secondary sources ( n alkane, EC/sterane and inorganic ion factors) exhibit similar contribution time series ( r = 0.92-0.98) with their corresponding factors ( n alkane, sterane and nitrate+sulfate factors) in the current work. Three other factors (light n alkane/PAH, PAH and summer/odd n alkane factors) are linked with pollution sources influenced by atmospheric processes (e.g. G/P partitioning, photochemical reaction), and were less correlated ( r = 0.69-0.84) with their corresponding factors (light SVOC, PAH and bulk carbon factors) in the current work, suggesting that the source apportionment results derived from particle-only SVOC data could be affected by atmospheric processes. PMF analysis was also performed on three temperature-stratified subsets of the total SVOC data, representing ambient sampling during cold (daily average temperature < 10 °C), warm (≥ 10 °C and ≤ 20 °C) and hot (> 20 °C) periods. Unlike the particle only-based study, in this work the factor characterized by the low molecular weight (MW) compounds (light SVOC factor) exhibited strong correlations ( r = 0.82-0.98) between the full data set and each sub-data set solution, indicating that the impacts of G/P partitioning on receptor-based source apportionment could be eliminated by using total SVOC concentrations.

Contributions and source identification of biogenic and anthropogenic hydrocarbons to secondary organic aerosols at Mt. Tai in 2014.

PubMed

Zhu, Yanhong; Yang, Lingxiao; Kawamura, Kimitaka; Chen, Jianmin; Ono, Kaori; Wang, Xinfeng; Xue, Likun; Wang, Wenxing

2017-01-01

Ambient fine particulate matter (PM 2.5 ) and volatile organic compounds (VOCs) collected at Mt. Tai in summer 2014 were analysed and the data were used to identify the contribution of biogenic and anthropogenic hydrocarbons to secondary organic aerosols (SOA) and their sources and potential source areas in high mountain regions. Compared with those in 2006, the 2014 anthropogenic SOA tracers in PM 2.5 aerosols and VOC species related to vehicular emissions exhibited higher concentrations, whereas the levels of biogenic SOA tracers were lower, possibly due to decreased biomass burning. Using the SOA tracer and parameterisation method, we estimated the contributions from biogenic and anthropogenic VOCs, respectively. The results showed that the average concentration of biogenic SOA was 1.08 ± 0.51 μg m -3 , among which isoprene SOA tracers were dominant. The anthropogenic VOC-derived SOA were 7.03 ± 1.21 μg m -3 and 1.92 ± 1.34 μg m -3 under low- and high-NO x conditions, respectively, and aromatics made the greatest contribution. However, the sum of biogenic and anthropogenic SOA only contributed 18.1-49.1% of the total SOA. Source apportionment by positive matrix factorisation (PMF) revealed that secondary oxidation and biomass burning were the major sources of biogenic SOA tracers. Anthropogenic aromatics mainly came from solvent use, fuel and plastics combustion and vehicular emissions. However, for > C6 alkanes and cycloalkanes, vehicular emissions and fuel and plastics combustion were the most important contributors. The potential source contribution function (PSCF) identified the Bohai Sea Region (BSR) as the major source area for organic aerosol compounds and VOC species at Mt. Tai. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical Characterization and Source Apportionment of Size Fractionated Atmospheric Aerosols, and, Evaluating Student Attitudes and Learning in Large Lecture General Chemistry Classes

NASA Astrophysics Data System (ADS)

Allen, Gregory Harold

Chemical speciation and source apportionment of size fractionated atmospheric aerosols were investigated using laser desorption time-of-flight mass spectrometry (LD TOF-MS) and source apportionment was carried out using carbon-14 accelerator mass spectrometry (14C AMS). Sample collection was carried out using the Davis Rotating-drum Unit for Monitoring impact analyzer in Davis, Colfax, and Yosemite, CA. Ambient atmospheric aerosols collected during the winter of 2010/11 and 2011/12 showed a significant difference in the types of compounds found in the small and large sized particles. The difference was due to the increase number of oxidized carbon species that were found in the small particles size ranges, but not in the large particles size ranges. Overall, the ambient atmospheric aerosols collected during the winter in Davis, CA had and average fraction modern of F14C = 0.753 +/- 0.006, indicating that the majority of the size fractionated particles originated from biogenic sources. Samples collected during the King Fire in Colfax, CA were used to determine the contribution of biomass burning (wildfire) aerosols. Factor analysis was used to reduce the ions found in the LD TOF-MS analysis of the King Fire samples. The final factor analysis generated a total of four factors that explained an overall 83% of the variance in the data set. Two of the factors correlated heavily with increased smoke events during the sample period. The increased smoke events produced a large number of highly oxidized organic aerosols (OOA2) and aromatic compounds that are indicative of biomass burning organic aerosols (WBOA). The signal intensities of the factors generated in the King Fire data were investigated in samples collected in Yosemite and Davis, CA to look at the impact of biomass burning on ambient atmospheric aerosols. In both comparison sample collections the OOA2 and WBOA factors both increased during biomass burning events located near the sampling sites. The correlation between the OOA2 and WBOA factors and smoke levels indicates that these factors can be used to identify the influence of biomass burning on ambient aerosols. The effectiveness of using the ChemWiki instead of a traditional textbook was investigated during the spring quarter of 2014. Student performance was measured using common midterms, a final, and a pre/post content exams. We also employed surveys, the Colorado Learning Attitudes about Science Survey (CLASS) for Chemistry, and a weekly time-on-task survey to quantify students' attitudes and study habits. The effectiveness of the ChemWiki compared to a traditional textbook was examined using multiple linear regression analysis with a standard non-inferiority testing framework. Results show that the performance of students in the section who were assigned readings from the ChemWiki was non-inferior to the performance of students in the section who were assigned readings from the traditional textbook, indicating that the ChemWiki does not substantially differ from the standard textbook in terms of student learning outcomes. The results from the surveys also suggest that the two classes were similar in their beliefs about chemistry and overall average time spent studying. These results indicate that the ChemWiki is a viable cost-saving alternative to traditional textbooks. The impact of using active learning techniques in a large lecture general chemistry class was investigated by assessing student performance and attitudes during the fall 2014 and winter 2015 quarters. One instructor applied active learning strategies while the remaining instructors employed more traditional lecture styles. Student performance, learning, learning environments, and attitudes were measured using a standardized pre/post exams, common final exams, classroom observations, and the CLASS chemistry instrument in large lecture general chemistry courses. Classroom observation data showed that the active learning class was the most student centered and of the other classes two instructors were transitional in their teaching style and the remaining two primarily employed traditional lecture techniques. The active learning class had the highest student performance but the difference was only statistically significant when compared to the two traditional lecture classes. Overall, our data showed a trend that student performance increased as the instructional style became more student centered. Student attitudes didn't seem to correlate with any specific instructional style and the students in the active learning class had similar attitudes to the other general students. The active learning class was successful in increasing the average time students spent studying outside of the class, a statistically significant difference of about 1.5 to 3.0 hrs/week.

Changes in concentration, composition and source contribution of atmospheric organic aerosols by shifting coal to natural gas in Urumqi

NASA Astrophysics Data System (ADS)

Ren, Yanqin; Wang, Gehui; Wu, Can; Wang, Jiayuan; Li, Jianjun; Zhang, Lu; Han, Yanni; Liu, Lang; Cao, Cong; Cao, Junji; He, Qing; Liu, Xinchun

2017-01-01

Size-segregated aerosols were collected in Urumqi, a megacity in northwest China, during two heating seasons, i.e., before (heating season І: January-March 2012) and after (heating season II: January-March 2014) the project "shifting coal to natural gas", and determined for n-alkanes, PAHs and oxygenated PAHs to investigate the impact of replacement of coal by natural gas on organic aerosols in the urban atmosphere. Our results showed that compared to those in heating season I concentrations of n-alkanes, PAHs and OPAHs decreased by 74%, 74% and 82% in heating season II, respectively. Source apportionment analysis suggested that coal combustion, traffic emission and biomass burning are the major sources of the determined organics during the heating seasons in Urumqi. Traffic emission is the main source for n-alkanes in the city. Coal combustion is the dominant source of PAHs and OPAHs in heating season І, but traffic emission becomes their major source in heating season ІI. Relative contributions of coal combustion to n-alkanes, PAHs and OPAHs in Urumqi decreased from 21 to 75% in heating season I to 4.0-21% in heating season II due to the replacement of coal with natural gas for house heating. Health risk assessment further indicated that compared with that in heating season I the number of lung cancer related to PAHs exposure in Urumqi decreased by 73% during heating season II due to the project implementation. Our results suggest that replacing coal by clean energy sources for house heating will significantly mitigate air pollution and improve human health in China.

Composition and sources of fine particulate matter across urban and rural sites in the Midwestern United States

PubMed Central

Kundu, Shuvashish; Stone, Elizabeth. A.

2014-01-01

The composition and sources of fine particulate matter (PM2.5) were investigated in rural and urban locations in Iowa, located in the agricultural and industrial Midwestern United States from April 2009 to December 2012. Major chemical contributors to PM2.5 mass were sulfate, nitrate, ammonium, and organic carbon. Non-parametric statistical analyses demonstrated that the two rural sites had significantly enhanced levels of crustal materials (Si, Al) driven by agricultural activities and unpaved roads. Meanwhile, the three urban areas had enhanced levels of secondary aerosol (nitrate, sulfate, and ammonium) and combustion (organic and elemental carbon). The heavily industrialized Davenport site had significantly higher levels of PM2.5 and trace metals (Fe, Pb, Zn), demonstrating the important local impact of industrial point sources on air quality. Sources of PM2.5 were evaluated by the multi-variant positive matrix factorization (PMF) source apportionment model. For each individual site, seven to nine factors were identified: secondary sulfate (accounting for 29–30% of PM2.5), secondary nitrate (17–24%), biomass burning (9–21%), gasoline combustion (6–16), diesel combustion (3–9%), dust (6–11%), industry (0.4–5%) and winter salt (2–6%). Source contributions demonstrated a clear urban enhancement in PM2.5 from gasoline engines (by a factor of 1.14) and diesel engines (by a factor of 2.3), which is significant due to the well-documented negative health impacts of vehicular emissions. This study presents the first source apportionment results from the state of Iowa and is broadly applicable to understanding the differences in anthropogenic and natural sources in the urban-rural continuum of particle air pollution. PMID:24736797

Chemical speciation and source apportionment of Non-Methane Volatile Organic Compounds (NMVOCs) in a Middle Eastern country

NASA Astrophysics Data System (ADS)

Salameh, Therese; Sauvage, Stéphane; Afif, Charbel; Borbon, Agnès; Locoge, Nadine

2014-05-01

NMVOCs, emitted from various sources, are of particular interest since they contribute to the formation of tropospheric ozone, PAN and secondary organic aerosols resulting in negative impacts on human health, climate and on the environment. To identify abatement measures, a profound knowledge of emission sources and their composition is a prerequisite. Air pollution in the Middle East region remains difficult to assess and understand because of a lack of ground-based measurements and the limited information on NMVOC chemical speciation and source apportionment. Based on a large database of NMVOC observations obtained in Beirut, the capital of Lebanon (a developing country in the Middle East region, located in Western Asia on the eastern shore of the Mediterranean Sea), the overall objective of this work is to apportion the sources of NMVOCs encountered in Lebanon. First, source profiles were determined with field measurements close to the main potential emitters namely the road transport, gasoline vapour, power generation and solvent uses. The results obtained are compared to other studies held in other regions and are used to assess the emission inventory developed for Lebanon. Secondly, two intensive field campaigns were held in a receptor site in Beirut during summer 2011 and winter 2012 in order to obtain a large time resolved dataset. The PMF analysis of this dataset was applied to apportion anthropogenic sources in this area. In both seasons, combustion (road transport and power generation) and gasoline evaporation, especially in winter, were the main sources contributing to the NMVOCs in Beirut. The results will support model implementation especially by completing the emission inventory established for the year 2010 by Waked et al. 2012 according to the EEA/EMEP guidelines because of the lack of Lebanon-specific emission factor.

Contributions to cities' ambient particulate matter (PM): A systematic review of local source contributions at global level

NASA Astrophysics Data System (ADS)

Karagulian, Federico; Belis, Claudio A.; Dora, Carlos Francisco C.; Prüss-Ustün, Annette M.; Bonjour, Sophie; Adair-Rohani, Heather; Amann, Markus

2015-11-01

For reducing health impacts from air pollution, it is important to know the sources contributing to human exposure. This study systematically reviewed and analysed available source apportionment studies on particulate matter (of diameter of 10 and 2.5 microns, PM10 and PM2.5) performed in cities to estimate typical shares of the sources of pollution by country and by region. A database with city source apportionment records, estimated with the use of receptor models, was also developed and available at the website of the World Health Organization. Systematic Scopus and Google searches were performed to retrieve city studies of source apportionment for particulate matter. Six source categories were defined. Country and regional averages of source apportionment were estimated based on city population weighting. A total of 419 source apportionment records from studies conducted in cities of 51 countries were used to calculate regional averages of sources of ambient particulate matter. Based on the available information, globally 25% of urban ambient air pollution from PM2.5 is contributed by traffic, 15% by industrial activities, 20% by domestic fuel burning, 22% from unspecified sources of human origin, and 18% from natural dust and salt. The available source apportionment records exhibit, however, important heterogeneities in assessed source categories and incompleteness in certain countries/regions. Traffic is one important contributor to ambient PM in cities. To reduce air pollution in cities and the substantial disease burden it causes, solutions to sustainably reduce ambient PM from traffic, industrial activities and biomass burning should urgently be sought. However, further efforts are required to improve data availability and evaluation, and possibly to combine with other types of information in view of increasing usefulness for policy making.

Source apportionment of PM10 by positive matrix factorization in urban area of Mumbai, India.

PubMed

Gupta, Indrani; Salunkhe, Abhaysinh; Kumar, Rakesh

2012-01-01

Particulate Matter (PM(10)) has been one of the main air pollutants exceeding the ambient standards in most of the major cities in India. During last few years, receptor models such as Chemical Mass Balance, Positive Matrix Factorization (PMF), PCA-APCS and UNMIX have been used to provide solutions to the source identification and contributions which are accepted for developing effective and efficient air quality management plans. Each site poses different complexities while resolving PM(10) contributions. This paper reports the variability of four sites within Mumbai city using PMF. Industrial area of Mahul showed sources such as residual oil combustion and paved road dust (27%), traffic (20%), coal fired boiler (17%), nitrate (15%). Residential area of Khar showed sources such as residual oil combustion and construction (25%), motor vehicles (23%), marine aerosol and nitrate (19%), paved road dust (18%) compared to construction and natural dust (27%), motor vehicles and smelting work (25%), nitrate (16%) and biomass burning and paved road dust (15%) in Dharavi, a low income slum residential area. The major contributors of PM(10) at Colaba were marine aerosol, wood burning and ammonium sulphate (24%), motor vehicles and smelting work (22%), Natural soil (19%), nitrate and oil burning (18%).

PM SOURCE APPORTIONMENT/RECEPTOR MODELING

EPA Science Inventory

Source apportionment (receptor) models are mathematical procedures for identifying and quantifying the sources of ambient air pollutants and their effects at a site (the receptor), primarily on the basis of species concentration measurements at the receptor, and generally without...

Anthropogenic Osmium in Airborne Particles from Woods Hole, Massachusetts, USA

NASA Astrophysics Data System (ADS)

Peucker-Ehrenbrink, B.; Sen, I. S.; Geboy, N.

2012-12-01

The global geochemical cycle of osmium has been significantly disturbed by the introduction of automobile exhaust catalysts to convert noxious gas emissions into more benign forms. Anthropogenic osmium has been reported in rainwater, snow, and in the urban airborne particles from around the world to reveal global-scale osmium pollution [1, 2]. In this study, we report on the platinum group element (PGE) concentrations and osmium isotope ratios of airborne particles (PM10) collected in Woods Hole, a small coastal town in Massachusetts to better understand inputs of anthropogenic osmium to rural environments. We further investigate the use of osmium isotopes to track sources of airborne particles and support source apportionment studies on a continental scale. The samples used in this study were collected at Woods Hole Oceanographic Institution over one year (2008-2009). From this collection twelve samples for which the backward air mass trajectories have been determined were selected for osmium isotope analyses. Our results show that the osmium and platinum concentrations are an order of magnitude lower when compared to downtown Boston [2]. The average Os, Pt and Ir concentrations are 0.006±0.012, 0.019±0.023, and 0.685±0.634 pg m-3, respectively. The 187Os/188Os of the aerosols range from 0.275 to 0.788. As continental crust is radiogenic (187Os/188Os >1) and PGE ore bodies generally have unradiogenic 187Os/188Os (~0.2), the unradiogenic 187Os/188Os signature of the aerosols indicates anthropogenic contributions. With 95% of the total osmium mobilization on land being attributed to human activities [3], it is clear that human imprint on airborne particles is not restricted to urban centers with high traffic flows, but also affects rural environments. Aerosol particles that have backward air mass trajectories from the Southwest, the densely populated and industrialized Eastern seaboard, are characterized by unradiogenic osmium, while air masses from the North have radiogenic signatures. Our results suggest that 187Os/188Os has potential for source apportionment studies. [1] Rauch et al. (2005), Environ. Sci. Technol., 39, p. 9464-9470 [2] Chen et al. (2009), PNAS, 106, p. 7724-7728 [3] Sen and Peucker-Ehrenbrink (2012), Environ. Sci. Technol., dx.doi.org/10.102/es301261x

Geochemistry of regional background aerosols in the Western Mediterranean

NASA Astrophysics Data System (ADS)

Pey, J.; Pérez, N.; Castillo, S.; Viana, M.; Moreno, T.; Pandolfi, M.; López-Sebastián, J. M.; Alastuey, A.; Querol, X.

2009-11-01

The chemical composition of regional background aerosols, and the time variability and sources in the Western Mediterranean are interpreted in this study. To this end 2002-2007 PM speciation data from an European Supersite for Atmospheric Aerosol Research (Montseny, MSY, located 40 km NNE of Barcelona in NE Spain) were evaluated, with these data being considered representative of regional background aerosols in the Western Mediterranean Basin. The mean PM 10, PM 2.5 and PM 1 levels at MSY during 2002-2007 were 16, 14 and 11 µg/m 3, respectively. After compiling data on regional background PM speciation from Europe to compare our data, it is evidenced that the Western Mediterranean aerosol is characterised by higher concentrations of crustal material but lower levels of OM + EC and ammonium nitrate than at central European sites. Relatively high PM 2.5 concentrations due to the transport of anthropogenic aerosols (mostly carbonaceous and sulphate) from populated coastal areas were recorded, especially during winter anticyclonic episodes and summer midday PM highs (the latter associated with the transport of the breeze and the expansion of the mixing layer). Source apportionment analyses indicated that the major contributors to PM 2.5 and PM 10 were secondary sulphate, secondary nitrate and crustal material, whereas the higher load of the anthropogenic component in PM 2.5 reflects the influence of regional (traffic and industrial) emissions. Levels of mineral, sulphate, sea spray and carbonaceous aerosols were higher in summer, whereas nitrate levels and Cl/Na were higher in winter. A considerably high OC/EC ratio (14 in summer, 10 in winter) was detected, which could be due to a combination of high biogenic emissions of secondary organic aerosol, SOA precursors, ozone levels and insolation, and intensive recirculation of aged air masses. Compared with more locally derived crustal geological dusts, African dust intrusions introduce relatively quartz-poor but clay mineral-rich silicate PM, with more kaolinitic clays from central North Africa in summer, and more smectitic clays from NW Africa in spring.

Characterization of the wintertime particulate (PM1) pollution at an urban background site of Nicosia, Cyprus

NASA Astrophysics Data System (ADS)

Sciare, Jean; Kleanthous, Savvas; Pikridas, Michael; Vrekoussis, Mihalis; Oikonomou, Konstantina; Merabet, Hamza; Mihalopoulos, Nikos; Yassaa, Noureddine

2015-04-01

A 1-month intensive campaign was performed during December 2014 at Nicosia, Cyprus, a city of 240,000 inhabitants, representative of E. Mediterranean medium sized cities. This is the first of a series of intensive campaigns, part of the MISTRALS-ENVI-Med "CyAr" project (Cyprus Aerosols and gas precursors) and MISTRALS-ChArMEx program (Chemistry-Aerosol Mediterranean Experiment, http://charmex.lsce.ipsl.fr/), and , with the objective to distinguish between local and transported sources responsible for wintertime particulate pollution. The mass and composition of the major chemical constituents of submicron aerosols (PM1) was monitored at an urban background station located at the city's suburbs with a suite of real-time analyzers (TEOM 1400, OPC Grimm 1.108, Q-ACSM, Aethalometer AE31). Quality control of Q-ACSM and Aethalometer datasets was performed through closure studies (using co-located TEOM / OPC Grimm). The consistency of the dataset was further validated using the integrated (off-line) and real-time measurements performed by the local air quality network at other locations in the same city. Very high levels of Black Carbon and organics were systematically observed every night, typically maximizing at 22:00 local time, pointing to local combustion sources most probably related to domestic heating. Similar pattern has been observed in other cities in the Eastern Mediterranean (Pikridas et al., 2013) and partly has been attributed to the economic crisis (Vrekoussis et al., 2013). Source apportionment of organic aerosols (OA) was performed using the SourceFinder software (SoFi, http://www.psi.ch/acsm-stations/me-2) allowing the distinction between various primary/secondary OA sources that allowed us to better characterize the combustion sources responsible for the observed elevated nighttime PM1 levels. Acknowledgements: This campaign has been funded by MISTRALS (ENVI-Med CyAr & ChArMEx), CNRS-INSU, CEA, CyI, DLI, CDER and ECPL.

Proceedings from the Workshop on Research Needs for Assessment and Management of Non-Point Air Emissions from Department of Defense Activities held in Research Triangle Park, North Carolina on 19-21 February 2008

DTIC Science & Technology

2008-10-01

Chow, J.C. (2006). Feasibility of soil dust source apportionment by the pyrolysis-gas chromatography/mass spectrometry method. J. Air Waste Manage...receptor-oriented source apportionment models. • Develop monitoring methods to determine source and fence line amounts of fugitive dust emissions for...offsite impact, including evaluation with receptor- oriented source apportionment models 76 8.8.1 Background 76 8.8.2 Significance 77 8.8.3

Photochemical grid model implementation and application of VOC, NOx, and O3 source apportionment

EPA Science Inventory

For the purposes of developing optimal emissions control strategies, efficient approaches are needed to identify the major sources or groups of sources that contribute to elevated ozone (O3) concentrations. Source-based apportionment techniques implemented in photochemical grid m...

Day-night differences in the composition and sources of carbonaceous aerosol at a polluted regional background site in the Netherlands

NASA Astrophysics Data System (ADS)

Dusek, Ulrike; Broekema, Elise; Holzinger, Rupert; Röckmann, Thomas; Meijer, Harro

2017-04-01

The origin of carbonaceous aerosol differs during day- and night-time, because emissions from major sources such as traffic, biomass combustion, and secondary organic aerosol formation show a distinct diurnal pattern. Moreover, photochemical processing and evaporation of semi-volatile organic compounds are enhanced during day-time, due to the availability of sunlight and higher temperatures. Assessing day-night differences in sources and chemical composition can give an indication of the importance of local/regional carbon sources and processing, since day-night differences should be averaged out during long-range transport. If local sources dominate, one could expect a strong diurnal variation in the source profile, but if long-range transport dominates the diurnal variation would be much weaker. In this study we measure the isotopic (14C and 13C) and detailed chemical composition of the organic fraction of the aerosol on high volume PM2.5 filter samples that were collected separately during day and night time. Radiocarbon (14C) measurements are used to estimate three main aerosol sources of organic and elemental carbon (OC and EC): Fossil fuel combustion (ff), biomass combustion (bb), and biogenic sources (bio). The detailed chemical and stable isotopic composition are measured at different desorption temperatures from the filter, which separates the more and less refractory organic compounds. The composition of the organic aerosol is measured using an thermal-desporption Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) method (Holzinger et al, 2010) and the stable isotopic composition is measured using a thermal desorption IRMS method (Dusek et al., 2013). Source apportionment results using 14C show that the contribution of fossil fuel combustion to EC and OC is higher during day-time than during night-time. This is valid for all seasons. During night-time biomass combustion plays a bigger role as a source of carbonaceous aerosol. Even in the summer, when biomass combustion is a small source, its relative contribution increases between 19:00 and 07:00. However, the diurnal changes in source contributions are relatively moderate (e.g., the biomass burning contribution to TC increased from 31% to 43% for the winter sample with the most distinct day-night difference.) This highlights the importance of long-range transport as a source of the carbonaceous aerosol in this region. First results from chemical composition measurements on four of the samples show that the concentration of less refractory organic carbon (desorption temperature up to 200 °C) increases at night-time much more strongly than the concentration of the more refractory carbon. Similarly, the concentration of small organic compounds with m/z < 100 also increases more strongly than heavier compounds. This indicates partitioning of semi-volatile OC as a possible additional night-time source. The chemical composition will be studied in more detail, focusing on diurnal changes in O/C ratios, individual compounds and compound classes, such as hydrocarbons or organic acids. Dusek, U., Meusinger, C., Oyama, B., Ramon, W., de Wilde, P., Holzinger, R., and Röckmann, T.: A thermal desorption system for measuring δ 13 C ratios on organic aerosol, Journal of aerosol science, 66, 72-82, 2013. Holzinger, R., Williams, J., Herrmann, F., Lelieveld, J., Donahue, N., Röckmann, T., 2010. Aerosol analysis using a Thermal-Desorption Proton-Transfer-Reaction Mass Spectrometer (TD-PTR-MS): a new approach to study processing of organic aerosols. Atmospheric chemistry and physics 10, 2257-2267.

Source apportionment of carbonaceous chemical species to fossil fuel combustion, biomass burning and biogenic emissions by a coupled radiocarbon-levoglucosan marker method

NASA Astrophysics Data System (ADS)

Salma, Imre; Németh, Zoltán; Weidinger, Tamás; Maenhaut, Willy; Claeys, Magda; Molnár, Mihály; Major, István; Ajtai, Tibor; Utry, Noémi; Bozóki, Zoltán

2017-11-01

An intensive aerosol measurement and sample collection campaign was conducted in central Budapest in a mild winter for 2 weeks. The online instruments included an FDMS-TEOM, RT-OC/EC analyser, DMPS, gas pollutant analysers and meteorological sensors. The aerosol samples were collected on quartz fibre filters by a low-volume sampler using the tandem filter method. Elemental carbon (EC), organic carbon (OC), levoglucosan, mannosan, galactosan, arabitol and mannitol were determined, and radiocarbon analysis was performed on the aerosol samples. Median atmospheric concentrations of EC, OC and PM2.5 mass were 0.97, 4.9 and 25 µg m-3, respectively. The EC and organic matter (1.6 × OC) accounted for 4.8 and 37 %, respectively, of the PM2.5 mass. Fossil fuel (FF) combustion represented 36 % of the total carbon (TC = EC + OC) in the PM2.5 size fraction. Biomass burning (BB) was a major source (40 %) for the OC in the PM2.5 size fraction, and a substantial source (11 %) for the PM10 mass. We propose and apply here a novel, straightforward, coupled radiocarbon-levoglucosan marker method for source apportionment of the major carbonaceous chemical species. The contributions of EC and OC from FF combustion (ECFF and OCFF) to the TC were 11.0 and 25 %, respectively, EC and OC from BB (ECBB and OCBB) were responsible for 5.8 and 34 %, respectively, of the TC, while the OC from biogenic sources (OCBIO) made up 24 % of the TC. The overall relative uncertainty of the OCBIO and OCBB contributions was assessed to be up to 30 %, while the relative uncertainty for the other apportioned species is expected to be below 20 %. Evaluation of the apportioned atmospheric concentrations revealed some of their important properties and relationships among them. ECFF and OCFF were associated with different FF combustion sources. Most ECFF was emitted by vehicular road traffic, while the contribution of non-vehicular sources such as domestic and industrial heating or cooking using gas, oil or coal to OCFF was substantial. The mean contribution of BB to EC particles was smaller by a factor of approximately 2 than that of road traffic. The main formation processes of OCFF, OCBB and OCBIO from volatile organic compounds were jointly influenced by a common factor, which is most likely the atmospheric photochemistry, while primary organic emissions can also be important. Technological improvements and control measures for various BB appliances, together with efficient education and training of their users, in particular on the admissible fuel types, offer an important potential for improving the air quality in Budapest, and likely in other cities as well.

Importance of data comparability for multi-year trends and source apportionment of NMHC concentrations observed in France

NASA Astrophysics Data System (ADS)

Sauvage, Stéphane; Waked, Antoine; Leonardis, Thierry; Locoge, Nadine

2017-04-01

Non Methane Hydrocarbon Compounds (NMHCs) are of interest due to their potential health impact and their key role in atmospheric processes as precursors of secondary pollutants such as ozone (O3) and secondary organic aerosols (SOA). Hourly measurements of 31 non-methane hydrocarbons (NMHCs) were carried out at three urban sites in France over the period of a decade. The trends analysis showed a significant yearly decrease in pollutant concentrations over the study period and for the majority of species in the range of -1 to -7% in accordance with the decrease of NMHC emissions in France (-5 to -9%). Concentrations of long-lived species such as ethane and propane which are known as tracers of distant sources and natural gas remained constant. These trends are consistent with those recently described at urban and background sites in the northern mid-latitudes and with emission inventories. They are compared with the ones reported for 3 French rural sites (EMEP). A year per year source apportionment study using PMF was also conducted for 2 of the urban sites over the period 2005-2013. Using source fingerprints, five common anthropogenic sources were identified for Paris and Strasbourg: traffic-exhaust emissions (21±5%, 18±5%), evaporative sources (17±4%, 24±7%), natural gas & background (22±5%, 25±5%), residential heating (17±4%, 17±5%) and solvent use (19±7%, 12±5%). Biogenic sources were also identified and accounted for 4±1% of the total measured NMHC's at both sites. Along the presentation, the robustness of these results will be discussed regarding the site representativeness, the data comparability, and the temporal variation of the data quality

Assessment of light extinction at a European polluted urban area during wintertime: Impact of PM1 composition and sources.

PubMed

Vecchi, R; Bernardoni, V; Valentini, S; Piazzalunga, A; Fermo, P; Valli, G

2018-02-01

In this paper, results from receptor modelling performed on a well-characterised PM 1 dataset were combined to chemical light extinction data (b ext ) with the aim of assessing the impact of different PM 1 components and sources on light extinction and visibility at a European polluted urban area. It is noteworthy that, at the state of the art, there are still very few papers estimating the impact of different emission sources on light extinction as we present here, although being among the major environmental challenges at many polluted areas. Following the concept of the well-known IMPROVE algorithm, here a tailored site-specific approach (recently developed by our group) was applied to assess chemical light extinction due to PM 1 components and major sources. PM 1 samples collected separately during daytime and nighttime at the urban area of Milan (Italy) were chemically characterised for elements, major ions, elemental and organic carbon, and levoglucosan. Chemical light extinction was estimated and results showed that at the investigated urban site it is heavily impacted by ammonium nitrate and organic matter. Receptor modelling (i.e. Positive Matrix Factorization, EPA-PMF 5.0) was effective to obtain source apportionment; the most reliable solution was found with 7 factors which were tentatively assigned to nitrates, sulphates, wood burning, traffic, industry, fine dust, and a Pb-rich source. The apportionment of aerosol light extinction (b ext,aer ) according to resolved sources showed that considering all samples together nitrate contributed at most (on average 41.6%), followed by sulphate, traffic, and wood burning accounting for 18.3%, 17.8% and 12.4%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Source apportionment and location by selective wind sampling and Positive Matrix Factorization.

PubMed

Venturini, Elisa; Vassura, Ivano; Raffo, Simona; Ferroni, Laura; Bernardi, Elena; Passarini, Fabrizio

2014-10-01

In order to determine the pollution sources in a suburban area and identify the main direction of their origin, PM2.5 was collected with samplers coupled with a wind select sensor and then subjected to Positive Matrix Factorization (PMF) analysis. In each sample, soluble ions, organic carbon, elemental carbon, levoglucosan, metals, and Polycyclic Aromatic Hydrocarbons (PAHs) were determined. PMF results identified six main sources affecting the area: natural gas home appliances, motor vehicles, regional transport, biomass combustion, manufacturing activities, and secondary aerosol. The connection of factor temporal trends with other parameters (i.e., temperature, PM2.5 concentration, and photochemical processes) confirms factor attributions. PMF analysis indicated that the main source of PM2.5 in the area is secondary aerosol. This should be mainly due to regional contributions, owing to both the secondary nature of the source itself and the higher concentration registered in inland air masses. The motor vehicle emission source contribution is also important. This source likely has a prevalent local origin. The most toxic determined components, i.e., PAHs, Cd, Pb, and Ni, are mainly due to vehicular traffic. Even if this is not the main source in the study area, it is the one of greatest concern. The application of PMF analysis to PM2.5 collected with this new sampling technique made it possible to obtain more detailed results on the sources affecting the area compared to a classical PMF analysis.

Composition and source apportionment of fine particulate matter during extended calm periods in the city of Rijeka, Croatia

NASA Astrophysics Data System (ADS)

Ivošević, T.; Orlić, I.; Bogdanović Radović, I.; Čargonja, M.; Stelcer, E.

2017-09-01

In the city of Rijeka, Croatia, an extended, two-year aerosol pollution monitoring campaign was recently completed. During that period, 345 samples of fine fraction of aerosols were collected on stretched Teflon filters. All samples were analyzed by Ion Beam Analysis techniques Proton Induced X-ray Emission and Proton Induced γ-Ray Emission and concentrations of 22 elements were determined. Concentrations of black carbon were determined by Laser Integrated Plate Method. For the Bay of Kvarner, where the city of Rijeka is located, long periods of calm weather are common. As a consequence, during these periods, air pollution is steadily increasing. To pin-point and characterize local, mostly anthropogenic, air pollution sources, only samples collected during the extended calm periods were used in this work. As a cut-off wind speed, speed of 1.5 m/s was used. In that way, out of all 345 samples, only 188 were selected. Those samples were statistically evaluated by means of positive matrix factorization. Results show that from all anthropogenic sources (vehicles, secondary sulphates, smoke, heavy oil combustion, road dust, industry Fe and port activities) only secondary sulphates and heavy oil combustion were significantly higher (40% and 50%, respectively) during calm periods. On the other hand, natural components of aerosol pollution such as soil and sea salts, (typically present in concentrations of 1.4% and 9%, respectively) are practically non-existent for calm weather conditions.

The use of marine cloud water samples as a diagnostic tool for aqueous chemistry, cloud microphysical processes and dynamics

NASA Astrophysics Data System (ADS)

Crosbie, E.; Ziemba, L. D.; Moore, R.; Shook, M.; Jordan, C.; Thornhill, K. L., II; Winstead, E.; Shingler, T.; Brown, M.; MacDonald, A. B.; Dadashazar, H.; Sorooshian, A.; Weiss-Penzias, P. S.; Anderson, B.

2017-12-01

Clouds play several roles in the Earth's climate system. In addition to their clear significance to the hydrological cycle, they strongly modulate the shortwave and longwave radiative balance of the atmosphere, with subsequent feedback on the atmospheric circulation. Furthermore, clouds act as a conduit for the fate and emergence of important trace chemical species and are the predominant removal mechanism for atmospheric aerosols. Marine boundary layer clouds cover large swaths of the global oceans. Because of their global significance, they have attracted significant attention into understanding how changes in aerosols are translated into changes in cloud macro- and microphysical properties. The circular nature of the influence of clouds-on-aerosols and aerosols-on-clouds has been used to explain the chaotic patterns often seen in marine clouds, however, this feedback also presents a substantial hurdle in resolving the uncertain role of anthropogenic aerosols on climate. Here we discuss ways in which the chemical constituents found in cloud water can offer insight into the physical and chemical processes inherent in marine clouds, through the use of aircraft measurements. We focus on observational data from cloud water samples collected during flights conducted over the remote North Atlantic and along coastal California across multiple campaigns. We explore topics related to aqueous processing, wet scavenging and source apportionment.

Source Contributions of Urban PM2.5 in the Beijing-Tianjin-Hebei Region: Changes between 2006 and 2013 and Relative Impacts of Emissions and Meteorology

NASA Astrophysics Data System (ADS)

Li, X.; Zhang, Q.; Zhang, Y.; Zheng, B.; Li, M.; Wang, K.; Chen, Y.; Wallington, T. J.; Han, W.; Shen, W.; Zhang, X.; He, K.

2015-12-01

Anthropogenic emissions in China have been controlled for years to improve ambient air quality. However, severe haze events caused by atmospheric aerosols with aerodynamic diameter less than or equal to 2.5 μm (PM2.5) have continued to occur, especially in the Beijing-Tianjin-Hebei (BTH) region. The Chinese government has set an ambitious goal to reduce urban PM2.5 concentrations by 25% in BTH by 2017 relative to the 2012 levels. Source apportionment (SA) is necessary to the development of the effective emission control strategies. In this work, the Comprehensive Air Quality Model with extensions (CAMx) with the Particulate Source Apportionment Technology (PSAT) is applied to the China domain for the years 2006 and 2013. Ambient surface concentrations of PM2.5 and its components are generally well reproduced. To quantify the contributions of each emission category or region to PM2.5 in BTH, the total emissions are divided into 7 emission categories and 11 source regions. The source contributions determined in this work are generally consistent with results from previous work. In 2013, the industrial (44%) and residential (27%) sectors are the dominant contributors to urban PM2.5 in BTH. The residential sector is the largest contributor in winter; the industry sector dominates in other seasons. A slight increasing trend (+3% for industry and +6% for residential) is found in 2013 relative to 2006, necessitating more attention to these two sectors. Local emissions make the largest contribution (40%-60%) for all receptors. Change of source contribution of PM2.5 in Beijing and northern Hebei are dominate by change of local emission. However, for Tianjin, and central and southern Hebei, change of meteorology condition are as important as change of emission, because regional inflow in these areas is more important than in Beijing and northern Hebei and can increase under unfavorable weather conditions, indicating a strong need for regional joint emission control efforts. The results in this study enhance the quantitative understanding of the source-receptor relationships and provide an important basis for policymaking to advance the control of PM2.5 pollution in China. Both sector-based and fuel-based source apportionment will be available to further improve the comparability with receptor model results.

Characterization and source apportionment of organic aerosol at 260 m on a meteorological tower in Beijing, China

NASA Astrophysics Data System (ADS)

Zhou, Wei; Wang, Qingqing; Zhao, Xiujuan; Xu, Weiqi; Chen, Chen; Du, Wei; Zhao, Jian; Canonaco, Francesco; Prévôt, André S. H.; Fu, Pingqing; Wang, Zifa; Worsnop, Douglas R.; Sun, Yele

2018-03-01

Despite extensive efforts toward the characterization of submicron aerosols at ground level in the megacity of Beijing, our understanding of aerosol sources and processes at high altitudes remains low. Here we conducted a 3-month real-time measurement of non-refractory submicron aerosol (NR-PM1) species at a height of 260 m from 10 October 2014 to 18 January 2015 using an aerosol chemical speciation monitor. Our results showed a significant change in aerosol composition from the non-heating period (NHP) to the heating period (HP). Organics and chloride showed clear increases during HP due to coal combustion emissions, while nitrate showed substantial decreases from 28 to 15-18 %. We also found that NR-PM1 species in the heating season can have average mass differences of 30-44 % under similar emission sources yet different meteorological conditions. Multi-linear engine 2 (ME-2) using three primary organic aerosol (OA) factors as constraints, i.e., fossil-fuel-related OA (FFOA) dominantly from coal combustion emissions, cooking OA (COA), and biomass burning OA (BBOA) resolved from ground high-resolution aerosol mass spectrometer measurements, was applied to OA mass spectra of ACSM. Two types of secondary OA (SOA) that were well correlated with nitrate and chloride-CO, respectively, were identified. SOA played a dominant role in OA during all periods at 260 m although the contributions were decreased from 72 % during NHP to 58-64 % during HP. The SOA composition also changed significantly from NHP to HP. While the contribution of oxygenated OA (OOA) was decreased from 56-63 to 32-40 %, less oxidized OOA (LO-OOA) showed a large increase from 9-16 to 24-26 %. COA contributed a considerable fraction of OA at high altitude, and the contribution was relatively similar across different periods (10-13 %). In contrast, FFOA showed a large increase during HP due to the influences of coal combustion emissions. We also observed very different OA composition between ground level and 260 m. Particularly, the contributions of COA and BBOA at the ground site were nearly twice those at 260 m, while SOA at 260 m was ˜ 15-34 % higher than that at ground level. Bivariate polar plots and back-trajectory analysis further illustrated the different source regions of OA factors in different seasons.

Linking trace gas measurements and molecular tracers of organic matter in aerosols for identification of ecosystem sources and types of wildfires in Central Siberia

NASA Astrophysics Data System (ADS)

Panov, A. V.; Prokushkin, A. S.; Korets, M. A.; Bryukhanov, A. V.; Myers-Pigg, A. N.; Louchouarn, P.; Sidenko, N. V.; Amon, R.; Andreae, M. O.; Heimann, M.

2016-11-01

Summer 2012 was one of the extreme wildfire years in Siberia. At the surface air monitoring station “ZOTTO” (60°48'N, 89°21'E, 114 m a.s.l.) in Central Siberia we observed biomass burning (BB) influence on the ongoing atmospheric measurements within more than 50 % of the time in June-July 2012 that indicates a 30 times greater wildfire signal compared to previously reported ordinary biomass burning signature for the study area. While previous studies thoroughly estimated a relative input of BB into aerosol composition (i.e. size distribution, physical and optical parameters etc.) at ZOTTO, in this paper we characterize the source apportionment of the smoke aerosols with molecular tracer techniques from large-scale wildfires occurred in 2012 in the two prevailing types of Central Siberian ecosystems: complexes of pine forests and bogs and dark coniferous forests. Wildfires in the selected ecosystems are highly differed by their combustion phase (flaming/smoldering), the type of fire (crown/ground), biomass fuel, and nature of soil that greatly determines the smoke particle composition. Anhydrosugars (levoglucosan and its isomers) and lignin phenols taken as indicators of the sources and the state of particulate matter (PM) inputs in the specific fire plumes were used as powerful tools to compare wildfires in different environmental conditions and follow the role and contribution of different sources of terrestrial organic matter in the transport of BB pollutants into the pristine atmosphere of boreal zone in Central Siberia.

Complex anthropogenic sources of platinum group elements in aerosols on Cape Cod, USA.

PubMed

Sen, Indra S; Peucker-Ehrenbrink, Bernhard; Geboy, Nicholas

2013-09-17

Platinum group elements (PGE) of anthropogenic origin have been reported in rainwater, snow, roadside soil and vegetation, industrial waste, and urban airborne particles around the world. As recent studies have shown that PGE are bioavailable in the environment and pose health risks at chronic levels, the extent of PGE pollution is of global concern. In this study, we report PGE concentrations and osmium isotope ((187)Os/(188)Os) ratios of airborne particles (particulate matter, PM10) collected in Woods Hole, a small coastal village on Cape Cod, Massachusetts, U.S.A. The sampling site is more than 100 km away from the nearest urban centers (Boston, Providence) and has no large industrial emission center within a 30 km radius. The study reveals that, although PGE concentrations in rural airborne particulate matter are orders of magnitude lower than in urban aerosols, 69% of the total osmium is of anthropogenic origin. Anthropogenic PGE signatures in airborne particles are thus not restricted to large cities with high traffic flows and substantial industries; they can also be found in rural environments. We further conclude that the combination of Pt/Rh concentration ratios and (187)Os/(188)Os composition can be used to trace PGE sources. The Pt/Rh and (187)Os/(188)Os composition of Woods Hole aerosols indicate that the anthropogenic PGE fraction is primarily sourced from ore smelting processes, with possible minor contributions from fossil fuel burning and automobile catalyst-derived materials. Our results further substantiate the use of (187)Os/(188)Os in source apportionment studies on continental scales.

SOURCE APPORTIONMENT OF EXPOSURES TO VOLATILE ORGANIC COMPOUNDS: I. EVALUATION OF RECEPTOR MODELS USING SIMULATED EXPOSURE DATA. (R826788)

EPA Science Inventory

Four receptor-oriented source apportionment models were evaluated by applying them to simulated personal exposure data for select volatile organic compounds (VOCs) that were generated by Monte Carlo sampling from known source contributions and profiles. The exposure sources mo...

DEVELOPMENT AND EVALUATION OF PM 2.5 SOURCE APPORTIONMENT METHODOLOGIES

EPA Science Inventory

The receptor model called Positive Matrix Factorization (PMF) has been extensively used to apportion sources of ambient fine particulate matter (PM_2.5), but the accuracy of source apportionment results currently remains unknown. In addition, air quality forecast model...

Chemical characterization of atmospheric particles and source apportionment in the vicinity of a steelmaking industry.

PubMed

Almeida, S M; Lage, J; Fernández, B; Garcia, S; Reis, M A; Chaves, P C

2015-07-15

The objective of this work was to provide a chemical characterization of atmospheric particles collected in the vicinity of a steelmaking industry and to identify the sources that affect PM10 levels. A total of 94 PM samples were collected in two sampling campaigns that occurred in February and June/July of 2011. PM2.5 and PM2.5-10 were analyzed for a total of 22 elements by Instrumental Neutron Activation Analysis and Particle Induced X-ray Emission. The concentrations of water soluble ions in PM10 were measured by Ion Chromatography and Indophenol-Blue Spectrophotometry. Positive Matrix Factorization receptor model was used to identify sources of particulate matter and to determine their mass contribution to PM10. Seven main groups of sources were identified: marine aerosol identified by Na and Cl (22%), steelmaking and sinter plant represented by As, Cr, Cu, Fe, Ni, Mn, Pb, Sb and Zn (11%), sinter plant stack identified by NH4(+), K and Pb (12%), an unidentified Br source (1.8%), secondary aerosol from coke making and blast furnace (19%), fugitive emissions from the handling of raw material, sinter plant and vehicles dust resuspension identified by Al, Ca, La, Si, Ti and V (14%) and sinter plant and blast furnace associated essentially with Fe and Mn (21%). Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous factor analysis of organic particle and gas mass spectra: AMS and PTR-MS measurements at an urban site

NASA Astrophysics Data System (ADS)

Slowik, J. G.; Vlasenko, A.; McGuire, M.; Evans, G. J.; Abbatt, J. P. D.

2009-03-01

During the winter component of the SPORT (Seasonal Particle Observations in the Region of Toronto) field campaign, particulate non-refractory chemical composition and concentration of selected volatile organic compounds (VOCs) were measured by an Aerodyne time-of-flight aerosol mass spectrometer (AMS) and a proton transfer reaction-mass spectrometer (PTR-MS), respectively. Sampling was performed in downtown Toronto ~15 m from a major road. The mass spectra from the AMS and PTR-MS were combined into a unified dataset, which was analyzed using positive matrix factorization (PMF). The two instruments were given equal weight in the PMF analysis by application of a scaling factor to the uncertainties of each instrument. A residual based metric, Δesc, was used to evaluate the relative weight. The PMF analysis yielded a 5-factor solution that included factors characteristic of regional transport, local traffic emissions, charbroiling, and oxidative processing. The unified dataset provides information on particle and VOC sources and atmospheric processing that cannot be obtained from the datasets of the individual instruments, such as apportionment of oxygenated VOCs to direct emission sources vs. secondary reaction products, improved correlation of oxygenated aerosol factors with photochemical age, and increased detail regarding the composition of oxygenated organic aerosol factors. This analysis represents the first application of PMF to a unified AMS/PTR-MS dataset.

Towards the isolation and estimation of elemental carbon in atmospheric aerosols using supercritical fluid extraction and thermo-optical analysis.

PubMed

Azeem, Hafiz Abdul; Martinsson, Johan; Stenström, Kristina Eriksson; Swietlicki, Erik; Sandahl, Margareta

2017-07-01

Air-starved combustion of biomass and fossil fuels releases aerosols, including airborne carbonaceous particles, causing negative climatic and health effects. Radiocarbon analysis of the elemental carbon (EC) fraction can help apportion sources of its emission, which is greatly constrained by the challenges in isolation of EC from organic compounds in atmospheric aerosols. The isolation of EC using thermo-optical analysis is however biased by the presence of interfering compounds that undergo pyrolysis during the analysis. EC is considered insoluble in all acidic, basic, and organic solvents. Based on the property of insolubility, a sample preparation method using supercritical CO 2 and methanol as co-solvent was developed to remove interfering organic compounds. The efficiency of the method was studied by varying the density of supercritical carbon dioxide by means of temperature and pressure and by varying the methanol content. Supercritical CO 2 with 10% methanol by volume at a temperature of 60 °C, a pressure of 350 bar and 20 min static mode extraction were found to be the most suitable conditions for the removal of 59 ± 3% organic carbon, including compounds responsible for pyrolysis with 78 ± 16% EC recovery. The results indicate that the method has potential for the estimation and isolation of EC from OC for subsequent analysis methods and source apportionment studies.

Quantification of Aerosol Derived Particulate Matter and Trace gases in the Coastal Belt of Kochi, Kerala, India

NASA Astrophysics Data System (ADS)

H, S. C.

2016-02-01

Aerosol chemistry is a window to unravel the various environmental health hazard problems. This open forum which deals with the study of formation, interaction, transformation of aerosol species, which could enable in the assessment of biogeochemical cycling of anthropogenic and toxic species. It also preserves the temperature balance and reservoir and sink for nutrients, trace metals and organic species. An inventory of air pollutants is a proactive and necessary first step towards the control of air pollution. Surveys and studies on the sources of pollution and their apportionment to different sources are a pre-requisite for alleviating environmental disorder. The Kochi City (The Queen of Arabian Sea), Kerala, India is a fast growing industrial region where mounting urbanization has been affecting the quality of the atmospheric environment. Cochin estuarine environment is progressively affected by marine pollution concomitant by industrial hazardous chemicals and municipal waste. Further, rapid urbanization and industrialization has lead to lofting and large scale advection of these omnipresent species in the atmosphere. Studies were conducted to assess the significance and potential impact occupied to these ubiquitous species. The major gaseous pollutants include gases like sulphur dioxide, nitrogen dioxide, ammonia and particulate matter (PM). An attempt was performed to unravel the inorganic species in the atmosphere and programmed by means of quantification of PM10 and trace gases. Their distribution pattern and outcomes are inferred.

Chemical composition of aerosol particles and light extinction apportionment before and during the heating season in Beijing, China

NASA Astrophysics Data System (ADS)

Wang, Qingqing; Sun, Yele; Jiang, Qi; Du, Wei; Sun, Chengzhu; Fu, Pingqing; Wang, Zifa

2015-12-01

Despite extensive efforts into characterization of the sources and formation mechanisms of severe haze pollution in the megacity of Beijing, the response of aerosol composition and optical properties to coal combustion emissions in the heating season remain poorly understood. Here we conducted a 3 month real-time measurement of submicron aerosol (PM1) composition by an Aerosol Chemical Speciation Monitor and particle light extinction by a Cavity Attenuated Phase Shift extinction monitor in Beijing, China, from 1 October to 31 December 2012. The average (±σ) PM1 concentration was 82.4 (±73.1) µg/m3 during the heating period (HP, 15 November to 31 December), which was nearly 50% higher than that before HP (1 October to 14 November). While nitrate and secondary organic aerosol (SOA) showed relatively small changes, organics, sulfate, and chloride were observed to have significant increases during HP, indicating the dominant impacts of coal combustion sources on these three species. The relative humidity-dependent composition further illustrated an important role of aqueous-phase processing for the sulfate enhancement during HP. We also observed great increases of hydrocarbon-like OA (HOA) and coal combustion OA (CCOA) during HP, which was attributed to higher emissions at lower temperatures and coal combustion emissions, respectively. The relationship between light extinction and chemical composition was investigated using a multiple linear regression model. Our results showed that the largest contributors to particle extinction were ammonium nitrate (32%) and ammonium sulfate (28%) before and during HP, respectively. In addition, the contributions of SOA and primary OA to particle light extinction were quantified. The results showed that the OA extinction was mainly caused by SOA before HP and by SOA and CCOA during HP, yet with small contributions from HOA and cooking aerosol for the entire study period. Our results elucidate substantial changes of aerosol composition, formation mechanisms, and optical properties due to coal combustion emissions and meteorological changes in the heating season.

Selective Collection of Airborne Particulate Matter

DOE PAGES

Cheng, Meng -Dawn

2018-01-01

Here, airborne particulate matter (PM) or aerosol particles or simply aerosol are ubiquitous in the environment. They originate from natural processes such as wind erosion, road dust, forest fire, ocean spray and volcanic eruption, and man-made sources consuming fossil fuels resulting from utility power generation and transportation, and numerous industrial processes. Aerosols affect our daily life in many ways; PM reduces visibility in many polluted metropolitan areas, adversely impact human health and local air quality around the world. Aerosol alters cloud cycles and change atmospheric radiation balance. Changes in daily mortality associated with particulate air pollution were typically estimated atmore » approximately 0.5–1.5% per 10 µg m –3 increase in PM10 concentrations. Laden et al. (2006) found “an increase in overall mortality associated with each 10 µg m –3 increase in PM2.5 concentration either as the overall mean (rate ratio [RR], 1.16; 95% confidence interval [CI], 1.07–1.26) or as exposure in the year of death (RR, 1.14; 95% CI, 1.06–1.22). PM2.5 exposure was associated with lung cancer (RR, 1.27; 95% CI, 0.96–1.69) and cardiovascular deaths (RR, 1.28; 95% CI, 1.13–1.44). Improved overall mortality was associated with decreased mean PM 2.5 (10 µg m –3) between periods (RR, 0.73; 95% CI, 0.57–0.95)”. Aerosol particles also play an important role in source identification and apportionment. Since the PM problem is associated with many facets of societal issues such as energy production and economic development, making progress on reducing the effects of PM will require integrated strategies that bring together scientists, engineers and decision makers from different disciplines to consider tradeoffs.« less

Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

NASA Astrophysics Data System (ADS)

Ulevicius, V.; Byčenkienė, S.; Bozzetti, C.; Vlachou, A.; Plauškaitė, K.; Mordas, G.; Dudoitis, V.; Abbaszade, G.; Remeikis, V.; Garbaras, A.; Masalaite, A.; Blees, J.; Fröhlich, R.; Dällenbach, K. R.; Canonaco, F.; Slowik, J. G.; Dommen, J.; Zimmermann, R.; Schnelle-Kreis, J.; Salazar, G. A.; Agrios, K.; Szidat, S.; El Haddad, I.; Prévôt, A. S. H.

2015-09-01

In early spring the Baltic region is frequently affected by high pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB) on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1) was measured by an Aerodyne aerosol chemical speciation monitor (ACSM) and a source apportionment with the multilinear engine (ME-2) running the positive matrix factorization (PMF) model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m-3 and black carbon (BC) up to 17 μg m-3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C) measurements of the elemental (EC) and organic (OC) carbon fractions. Non-fossil organic carbon (OCnf) was the dominant fraction of PM1, with the primary (POCnf) and secondary (SOCnf) fractions contributing 26-44 % and 13-23 % to the TC, respectively. 5-8 % of the TC had a primary fossil origin (POCf), whereas the contribution of fossil secondary organic carbon (SOCf) was 4-13 %. Non-fossil EC (ECnf) and fossil EC (ECf) ranged from 13-24 % and 7-12 %, respectively. Isotope ratio of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

NASA Astrophysics Data System (ADS)

Ulevicius, Vidmantas; Byčenkienė, Steigvilė; Bozzetti, Carlo; Vlachou, Athanasia; Plauškaitė, Kristina; Mordas, Genrik; Dudoitis, Vadimas; Abbaszade, Gülcin; Remeikis, Vidmantas; Garbaras, Andrius; Masalaite, Agne; Blees, Jan; Fröhlich, Roman; Dällenbach, Kaspar R.; Canonaco, Francesco; Slowik, Jay G.; Dommen, Josef; Zimmermann, Ralf; Schnelle-Kreis, Jürgen; Salazar, Gary A.; Agrios, Konstantinos; Szidat, Sönke; El Haddad, Imad; Prévôt, André S. H.

2016-05-01

In early spring the Baltic region is frequently affected by high-pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB) on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1) was measured by an Aerodyne aerosol chemical speciation monitor (ACSM) and a source apportionment with the multilinear engine (ME-2) running the positive matrix factorization (PMF) model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m-3 and black carbon (BC) up to 17 µg m-3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C) measurements of the elemental (EC) and organic (OC) carbon fractions. Non-fossil organic carbon (OCnf) was the dominant fraction of PM1, with the primary (POCnf) and secondary (SOCnf) fractions contributing 26-44 % and 13-23 % to the total carbon (TC), respectively. 5-8 % of the TC had a primary fossil origin (POCf), whereas the contribution of fossil secondary organic carbon (SOCf) was 4-13 %. Non-fossil EC (ECnf) and fossil EC (ECf) ranged from 13-24 and 7-13 %, respectively. Isotope ratios of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

Selective Collection of Airborne Particulate Matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Meng -Dawn

Here, airborne particulate matter (PM) or aerosol particles or simply aerosol are ubiquitous in the environment. They originate from natural processes such as wind erosion, road dust, forest fire, ocean spray and volcanic eruption, and man-made sources consuming fossil fuels resulting from utility power generation and transportation, and numerous industrial processes. Aerosols affect our daily life in many ways; PM reduces visibility in many polluted metropolitan areas, adversely impact human health and local air quality around the world. Aerosol alters cloud cycles and change atmospheric radiation balance. Changes in daily mortality associated with particulate air pollution were typically estimated atmore » approximately 0.5–1.5% per 10 µg m –3 increase in PM10 concentrations. Laden et al. (2006) found “an increase in overall mortality associated with each 10 µg m –3 increase in PM2.5 concentration either as the overall mean (rate ratio [RR], 1.16; 95% confidence interval [CI], 1.07–1.26) or as exposure in the year of death (RR, 1.14; 95% CI, 1.06–1.22). PM2.5 exposure was associated with lung cancer (RR, 1.27; 95% CI, 0.96–1.69) and cardiovascular deaths (RR, 1.28; 95% CI, 1.13–1.44). Improved overall mortality was associated with decreased mean PM 2.5 (10 µg m –3) between periods (RR, 0.73; 95% CI, 0.57–0.95)”. Aerosol particles also play an important role in source identification and apportionment. Since the PM problem is associated with many facets of societal issues such as energy production and economic development, making progress on reducing the effects of PM will require integrated strategies that bring together scientists, engineers and decision makers from different disciplines to consider tradeoffs.« less

77 FR 11974 - Approval and Promulgation of Implementation Plans; State of Iowa Regional Haze State...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-28

... and beyond. The modeling was based on PM Source Apportionment Technology (PSAT) for the Comprehensive... sources and the State adequately determined the apportionment of those pollutants from sources located... Class I areas caused by emissions of air pollutants from numerous sources located over a wide geographic...

Methods for Characterizing the Distribution of Exhaust Emissions from Light-Duty, Gasoline-Powered Motor Vehicles in the U.S. Fleet

EPA Science Inventory

Mobile sources significantly contribute to ambient concentrations of airborne particulate matter. Source apportionment studies for PMlO and PM2.5 indicate that mobile sources can be responsible for over half of the ambient PM measured in an urban area. Recent source apportionment...

Enterococcus and Escherichia coli fecal source apportionment with microbial source tracking genetic markers - is it feasible?

EPA Science Inventory

Fecal pollution is measured in surface waters using culture-based measurements of enterococci and Escherichia coli bacteria. Source apportionment of these two fecal indicator bacteria is an urgent need for prioritizing remediation efforts and quantifying health risks associated...

Spatial and temporal variation of sources contributing to quasi-ultrafine particulate matter PM0.36 in Augsburg, Germany.

PubMed

Li, Fengxia; Schnelle-Kreis, Jürgen; Cyrys, Josef; Wolf, Kathrin; Karg, Erwin; Gu, Jianwei; Orasche, Jürgen; Abbaszade, Gülcin; Peters, Annette; Zimmermann, Ralf

2018-08-01

to study the sources contributing to quasi-ultrafine particle (UFP) organic carbon and the spatial temporal variability of the sources. 24h quasi-UFP (particulate matter <0.36μm in this study) was sampled at a reference site continuously and at one of 5 other sites (T1, T2, T3, T4 and B1) in parallel in Augsburg, Germany from April 11th, 2014 to February 22nd, 2015, attempting to conduct 2-week campaigns at each site in 3 different seasons. Positive matrix factorization (PMF) was applied to measured organic tracers for source apportionment analyses. Pearson correlation coefficient r and coefficient of divergence (COD) were calculated to investigate spatial temporal variation of source contributions. 5 sources were identified comprising biomass burning (BB), traffic emissions (Traffic), biogenic secondary organic aerosol (bioSOA), isoprene originated secondary organic aerosol (isoSOA) and biomass burning related secondary organic aerosol (bbSOA). In general, good temporal correlation and uniform distribution within the study area are found for bioSOA and bbSOA, probably resulting from regional formation/transport. Lower temporal correlation and spatial heterogeneity of isoSOA were found at the city background site with local influence from green space and less traffic impact. BB demonstrated very good temporal correlation, but higher contributions at sites influenced by local residential heating emissions were observed. Traffic showed the least seasonality and lower correlation over time among the sources. However, it demonstrated low spatial heterogeneity of absolute contribution, and only a few days of elevated contribution was found at T3 when wind came directly from the street nearby. temporal correlation and spatial variability of sources contributing to the organic fraction of quasi-UFP vary among sites and source types and show source-specific characteristics. Therefore, caution should be taken when using one monitor site measurement to assess human exposure in health effect studies of quasi-UFP. Copyright © 2018 Elsevier B.V. All rights reserved.

Secondary inorganic aerosols in Europe: sources and the significant influence of biogenic VOC emissions, especially on ammonium nitrate

NASA Astrophysics Data System (ADS)

Aksoyoglu, Sebnem; Ciarelli, Giancarlo; El-Haddad, Imad; Baltensperger, Urs; Prévôt, André S. H.

2017-06-01

Contributions of various anthropogenic sources to the secondary inorganic aerosol (SIA) in Europe as well as the role of biogenic emissions on SIA formation were investigated using the three-dimensional regional model CAMx (comprehensive air quality model with extensions). Simulations were carried out for two periods of EMEP field campaigns, February-March 2009 and June 2006, which are representative of cold and warm seasons, respectively. Biogenic volatile organic compounds (BVOCs) are known mainly as precursors of ozone and secondary organic aerosol (SOA), but their role on inorganic aerosol formation has not attracted much attention so far. In this study, we showed the importance of the chemical reactions of BVOCs and how they affect the oxidant concentrations, leading to significant changes, especially in the formation of ammonium nitrate. A sensitivity test with doubled BVOC emissions in Europe during the warm season showed a large increase in secondary organic aerosol (SOA) concentrations (by about a factor of two), while particulate inorganic nitrate concentrations decreased by up to 35 %, leading to a better agreement between the model results and measurements. Sulfate concentrations decreased as well; the change, however, was smaller. The changes in inorganic nitrate and sulfate concentrations occurred at different locations in Europe, indicating the importance of precursor gases and biogenic emission types for the negative correlation between BVOCs and SIA. Further analysis of the data suggested that reactions of the additional terpenes with nitrate radicals at night were responsible for the decline in inorganic nitrate formation, whereas oxidation of BVOCs with OH radicals led to a decrease in sulfate. Source apportionment results suggest that the main anthropogenic source of precursors leading to formation of particulate inorganic nitrate is road transport (SNAP7; see Table 1 for a description of the categories), whereas combustion in energy and transformation industries (SNAP1) was the most important contributor to sulfate particulate mass. Emissions from international shipping were also found to be very important for both nitrate and sulfate formation in Europe. In addition, we also examined contributions from the geographical source regions to SIA concentrations in the most densely populated region of Switzerland, the Swiss Plateau.

Source apportionment of particulate matter and trace gases near a major refinery near the Houston Ship Channel

NASA Astrophysics Data System (ADS)

Wallace, Henry W.; Sanchez, Nancy P.; Flynn, James H.; Erickson, Mathew H.; Lefer, Barry L.; Griffin, Robert J.

2018-01-01

From February 7 to 27, 2015, a mobile air quality laboratory was deployed to a location proximate to a major refinery, the Port of Houston, and several neighborhoods to conduct measurements of atmospheric trace gases and particulate matter. Two statistical models were utilized to apportion the sources of pollution impacting this site and the denizens of the nearby neighborhoods. Positive matrix factorization (PMF) was performed on the organic signal of the aerosol mass spectra, resulting in five factors totaling an average of 4.1 μg/m3 of the organic aerosol: hydrocarbon-like (0.67 μg/m3), cooking (0.35 μg/m3) biomass burning (1.14 μg/m3), low-volatility oxidized (1.15 μg/m3), and semi-volatile oxidized (0.78 μg/m3). Principal component analysis was performed on daytime and nighttime data, including concentrations from PMF output, of other PM1 components, and of trace gases. This generated five daytime and five nighttime factors that explained 74.5% and 73.0% of the variance, respectively. The most important factors impacting this site were from mobile source exhaust and petrochemical aromatic compound emissions. Together these two factors also constitute most of the observed carcinogens.

Chemical composition of PM2.5 at an urban site of Chengdu in southwestern China

NASA Astrophysics Data System (ADS)

Tao, Jun; Cheng, Tiantao; Zhang, Renjian; Cao, Junji; Zhu, Lihua; Wang, Qiyuan; Luo, Lei; Zhang, Leiming

2013-07-01

PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous matter. The annual average of PM2.5 was 165 μg m-3, which is generally higher than measurements in other Chinese cities, suggesting serious particulate pollution issues in the city. Water soluble ions contributed 43.5% to the annual total PM2.5 mass, carbonaceous aerosols including elemental carbon and organic carbon contributed 32.0%, and trace elements contributed 13.8%. Distinct daily and seasonal variations were observed in the mass concentrations of PM2.5 and its components, reflecting the seasonal variations of different anthropogenic and natural sources. Weakly acidic to neutral particles were found for PM2.5. Major sources of PM2.5 identified from source apportionment analysis included coal combustion, traffic exhaust, biomass burning, soil dust, and construction dust emissions. The low nitrate: sulfate ratio suggested that stationary emissions were more important than vehicle emissions. The reconstructed masses of ammonium sulfate, ammonium nitrate, particulate carbonaceous matter, and fine soil accounted for 79% of the total measured PM2.5 mass; they also accounted for 92% of the total measured particle scattering.

Radiocarbon-based source apportionment of carbonaceous aerosols at a regional background site on Hainan Island, South China.

PubMed

Zhang, Yan-Lin; Li, Jun; Zhang, Gan; Zotter, Peter; Huang, Ru-Jin; Tang, Jian-Hui; Wacker, Lukas; Prévôt, André S H; Szidat, Sönke

2014-01-01

To assign fossil and nonfossil contributions to carbonaceous particles, radiocarbon ((14)C) measurements were performed on organic carbon (OC), elemental carbon (EC), and water-insoluble OC (WINSOC) of aerosol samples from a regional background site in South China under different seasonal conditions. The average contributions of fossil sources to EC, OC and WINSOC were 38 ± 11%, 19 ± 10%, and 17 ± 10%, respectively, indicating generally a dominance of nonfossil emissions. A higher contribution from fossil sources to EC (∼51%) and OC (∼30%) was observed for air-masses transported from Southeast China in fall, associated with large fossil-fuel combustion and vehicle emissions in highly urbanized regions of China. In contrast, an increase of the nonfossil contribution by 5-10% was observed during the periods with enhanced open biomass-burning activities in Southeast Asia or Southeast China. A modified EC tracer method was used to estimate the secondary organic carbon from fossil emissions by determining (14)C-derived fossil WINSOC and fossil EC. This approach indicates a dominating secondary component (70 ± 7%) of fossil OC. Furthermore, contributions of biogenic and biomass-burning emissions to contemporary OC were estimated to be 56 ± 16% and 44 ± 14%, respectively.

In situ measurement and source apportionment of aerosols in the Kathmandu valley, Nepal, April 2015.

NASA Astrophysics Data System (ADS)

DeCarlo, P. F.; Werden, B.; Goetz, J. D.; Giordano, M.; Bhave, P.; Jayarathne, T. S.; Stockwell, C.; Christian, T. J.; Nadler, W.; Panday, A. K.; Yokelson, R. J.; Stone, E. A.

2017-12-01

The Kathmandu Valley in Nepal is home to over 2.5 Million people, and is one of the fastest growing metropolitan areas in South Asia. It is subject to extreme pollution events due to numerous unregulated localized pollution sources and regional transport from the Indo-Gangetic Plain (IGP). Over 10% of Nepali fatalities are from lung disorders, making it the most common cause of death in the country. Previous field work has studied gas species, wintertime VOCs and PM in the valley. The Nepal Ambient Measurement and Site Testing Experiment [NAMaSTE] is the first deployment of a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) in Nepal and allows for a more comprehensive analysis of aerosol species and their source contributions. Ambient measurements for the NAMaSTE campaign were made in Bode, 8 km east of Kathmandu. Intensive measurements were made in April 2015, but cut short by the 2015 Gorka earthquake. HR-ToF-AMS measurements provided detailed chemical composition information on particulate matter in the valley. Ancillary measurements of chemical species CO, CO2, CH4, H2O, O3, NOx, BC and PM were carried out and compared to AMS data and meteorological parameters. AMS species show a clear diurnal pattern, with extremely elevated concentrations in the morning, with a wind shift to westerly in the afternoon. PMF was performed on the ambient data set, and mass spectral data was compared to source mass spectra generated from emission testing of various local sources measured during the campaign. The mean concentration of PM2.5 was 83 ± 45 µg/m3, which is above the 24 hour WHO exposure threshold of 25 µg/m3 and annual continous exposure limit of 10 µg/m3­­. Localized sources of anthropogenic emissions such as garbage burning, coal for brick kilns, dung and biomass burning for cooking and agriculture are likely sources of elevated pollutant emissions. Unmitigated burning of trash and biomass coupled with irregular fuels are a major source of pollutant species and aerosols in the undeveloped world.

Sophisticated Clean Air Strategies Required to Mitigate Against Particulate Organic Pollution

PubMed Central

Grigas, T.; Ovadnevaite, J.; Ceburnis, D.; Moran, E.; McGovern, F. M.; Jennings, S. G.; O’Dowd, C.

2017-01-01

Since the 1980’s, measures mitigating the impact of transboundary air pollution have been implemented successfully as evidenced in the 1980–2014 record of atmospheric sulphur pollution over the NE-Atlantic, a key region for monitoring background northern-hemisphere pollution levels. The record reveals a 72–79% reduction in annual-average airborne sulphur pollution (SO4 and SO2, respectively) over the 35-year period. The NE-Atlantic, as observed from the Mace Head research station on the Irish coast, can be considered clean for 64% of the time during which sulphate dominates PM1 levels, contributing 42% of the mass, and for the remainder of the time, under polluted conditions, a carbonaceous (organic matter and Black Carbon) aerosol prevails, contributing 60% to 90% of the PM1 mass and exhibiting a trend whereby its contribution increases with increasing pollution levels. The carbonaceous aerosol is known to be diverse in source and nature and requires sophisticated air pollution policies underpinned by sophisticated characterisation and source apportionment capabilities to inform selective emissions-reduction strategies. Inauspiciously, however, this carbonaceous concoction is not measured in regulatory Air Quality networks. PMID:28303958

Scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and aerosol time-of-flight mass spectrometry (ATOFMS) single particle analysis of metallurgy plant emissions.

PubMed

Arndt, J; Deboudt, K; Anderson, A; Blondel, A; Eliet, S; Flament, P; Fourmentin, M; Healy, R M; Savary, V; Setyan, A; Wenger, J C

2016-03-01

The chemical composition of single particles deposited on industrial filters located in three different chimneys of an iron-manganese (Fe-Mn) alloy manufacturing plant have been compared using aerosol time-of-flight mass spectrometry (ATOFMS) and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX). Very similar types of particles were observed using both analytical techniques. Calcium-containing particles dominated in the firing area of the sintering unit, Mn and/or Al-bearing particles were observed at the cooling area of the sintering unit, while Mn-containing particles were dominant at the smelting unit. SEM-EDX analysis of particles collected downstream of the industrial filters showed that the composition of the particles emitted from the chimneys is very similar to those collected on the filters. ATOFMS analysis of ore samples was also performed to identify particulate emissions that could be generated by wind erosion and manual activities. Specific particle types have been identified for each emission source (chimneys and ore piles) and can be used as tracers for source apportionment of ambient PM measured in the vicinity of the industrial site. Copyright © 2015 Elsevier Ltd. All rights reserved.

Carbonaceous aerosols in the Western Mediterranean during summertime and their contribution to the aerosol optical properties at ground level: First results of the ChArMEx-ADRIMED 2013 intensive campaign in Corsica

NASA Astrophysics Data System (ADS)

Sciare, Jean; Dulac, Francois; Feron, Anais; Crenn, Vincent; Sarda Esteve, Roland; Baisnee, Dominique; Bonnaire, Nicolas; Hamonou, Eric; Mallet, Marc; Lambert, Dominique; Nicolas, Jose B.; Bourrianne, Thierry; Petit, Jean-Eudes; Favez, Olivier; Canonaco, Francesco; Prevot, Andre; Mocnik, Grisa; Drinovec, Luka; Marpillat, Alexandre; Serrie, Wilfrid

2014-05-01

As part of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/), the CORSiCA (http://www.obs-mip.fr/corsica) and the ANR-ADRIMED programs, a large set of real-time measurements of carbonaceous aerosols was deployed in June 2013 at the Cape Corsica atmospheric supersite (http://gaw.empa.ch/gawsis/reports.asp?StationID=2076203042). Submicron organic aerosols (OA) were monitored every 30 min using an Aerosol Chemical Speciation Monitor (ACSM; Aerodyne Res. Inc. MA, USA); Fine (PM2.5) Organic Carbon (OC) and Elemental Carbon (EC) were measured every 2h using an OCEC Sunset Field Instrument (Sunset Lab, OR, USA) and every 12h using a low-vol (Leckel) filter sampler running at 2.3m3/h. Equivalent Black Carbon (BC) was monitored using two Aethalometers (models AE31 and AE33, Magee Scientific, US & Aerosol d.o.o., Slovenia) and a MAAP instrument (Thermo). Quality control of this large dataset was performed through chemical mass closure studies (using co-located SMPS and TEOM-FDMS) and direct comparisons with other real-time instruments running in parallel (Particle-Into-Liquid-Sampler-Ion-Chromatograph for ions, filter sampling, ...). Source apportionment of OA was then performed using the SourceFinder software (SoFi v4.5, http://www.psi.ch/acsm-stations/me-2) allowing the distinction between hydrogen- and oxygen-like organic aerosols (HOA and OOA, respectively) and highlighting the major contribution of secondary OA in the Western Mediterranean during summer. Using this time-resolved chemical information, reconstruction of the optical aerosol properties were performed and compared with integrating nephelometer (Model 3563, TSI, US) and photoacoustic extinctiometer (PAX, DMT, US) measurements performed in parallel. Results of these different closure studies (chemical/physical/optical) are presented and discussed here in details. They highlight the central role of carbonaceous aerosols on the optical properties of aerosols at ground level in the Western Mediterranean Sea during summertime. Acknowledgements: Aerosol measurements performed at Cape Corsica Station were mainly funded by ANR, CNRS-INSU, ADEME, Collectivité Territoriale de Corse through EU-FEDER Operational program 2007-2013, CEA, METEO-FRANCE, MGR-KROP, AEROSOL D.O.O., ECOMESURE, and ENVICONTROL

MONITORING AND SOURCE APPORTIONMENT OF PARTICULATE MATTER NEAR A LARGE PHOSPHORUS PRODUCTION FACILITY

EPA Science Inventory

A source apportionment study was conducted to identify sources within a large elemental phosphorus plant that contribute to exceedances of the National Ambient Air Quality Standard for 24-h PM10. Ambient data were collected at three monitoring sites from October 1996 through Ju...

Characterization of carbonaceous materials in PM2.5 and PM10 size fractions in Morogoro, Tanzania, during 2006 wet season campaign

NASA Astrophysics Data System (ADS)

Mkoma, Stelyus L.; Chi, Xuguang; Maenhaut, Willy

2010-05-01

Atmospheric aerosol samples in PM10 and PM2.5 size fractions were collected in parallel at a rural site in Morogoro during wet season in March and April 2006. All samples were analysed for the particulate matter mass, for organic, elemental, and total carbon (OC, EC, and TC), and for water-soluble OC (WSOC). The average PM10 and PM2.5 mass concentrations and associated standard deviations were 14 ± 13 μg/m 3 and 7.3 ± 4 μg/m 3 respectively. On average, TC accounted for 33% of the PM10 mass and 44% of the PM2.5 mass for the campaign. The average OC/PM percentage ratios were 27% and 33% in PM10 and PM2.5 size fractions respectively and a larger fraction of the OC was water-soluble. The observed low EC/TC mean percentage ratios of 10-14% respectively for PM10 and PM2.5 fractions indicate that the carbonaceous aerosol originates mainly from biogenic aerosols and/or biomass burning. A simple source apportionment approach was used to apportion the OC to biofuel and charcoal burning. On average, 93% of the PM10 OC was attributed to biofuel and 7% to charcoal burning in the 2006 wet season campaign. However, it is suggested that a contribution to the OC at Morogoro could also come from other natural biogenic matter, and/or biomass burning aerosols. The results for the sources of OC at Morogoro should therefore be considered with great caution.

Speciation of organic fractions does matter for aerosol source apportionment. Part 2: Intensive short-term campaign in the Paris area (France).

PubMed

Srivastava, D; Favez, O; Bonnaire, N; Lucarelli, F; Haeffelin, M; Perraudin, E; Gros, V; Villenave, E; Albinet, A

2018-09-01

The present study aimed at performing PM 10 source apportionment, using positive matrix factorization (PMF), based on filter samples collected every 4h at a sub-urban station in the Paris region (France) during a PM pollution event in March 2015 (PM 10 >50μgm -3 for several consecutive days). The PMF model allowed to deconvolve 11 source factors. The use of specific primary and secondary organic molecular markers favoured the determination of common sources such as biomass burning and primary traffic emissions, as well as 2 specific biogenic SOA (marine+isoprene) and 3 anthropogenic SOA (nitro-PAHs+oxy-PAHs+phenolic compounds oxidation) factors. This study is probably the first one to report the use of methylnitrocatechol isomers as well as 1-nitropyrene to apportion secondary OA linked to biomass burning emissions and primary traffic emissions, respectively. Secondary organic carbon (SOC) fractions were found to account for 47% of the total OC. The use of organic molecular markers allowed the identification of 41% of the total SOC composed of anthropogenic SOA (namely, oxy-PAHs, nitro-PAHs and phenolic compounds oxidation, representing 15%, 9%, 11% of the total OC, respectively) and biogenic SOA (marine+isoprene) (6% in total). Results obtained also showed that 35% of the total SOC originated from anthropogenic sources and especially PAH SOA (oxy-PAHs+nitro-PAHs), accounting for 24% of the total SOC, highlighting its significant contribution in urban influenced environments. Anthropogenic SOA related to nitro-PAHs and phenolic compounds exhibited a clear diurnal pattern with high concentrations during the night indicating the prominent role of night-time chemistry but with different chemical processes involved. Copyright © 2018 Elsevier B.V. All rights reserved.

Source apportionment of submicron organic aerosol at an urban background and a road site in Barcelona (Spain) during SAPUSS

NASA Astrophysics Data System (ADS)

Alier, M.; van Drooge, B. L.; Dall'Osto, M.; Querol, X.; Grimalt, J. O.; Tauler, R.

2013-10-01

This study investigates the contribution of potential sources to the submicron (PM1) organic aerosol (OA) simultaneously detected at an urban background (UB) and a road site (RS) in Barcelona during the 30 days of the intensive field campaign of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies, September-October 2010). A total of 103 filters at 12 h sampling time resolution were collected at both sites. Thirty-six neutral and polar organic compounds of known emission sources and photo-chemical transformation processes were analyzed by gas chromatography-mass spectrometry (GC-MS). The concentrations of the trace chemical compounds analyzed are herein presented and discussed. Additionally, OA source apportionment was performed by multivariate curve resolution-alternating least squares (MCR-ALS) and six OA components were identified at both sites: two were of primary anthropogenic OA origin and three of secondary OA origin, while a sixth one was not clearly defined. Primary organics from emissions of local anthropogenic activities (urban primary organic aerosol, or POA Urban), mainly traffic emissions but also cigarette smoke, contributed 43% (1.5 μg OC m-3) and 18% (0.4 μg OC m-3) to OA at RS and UB, respectively. A secondary primary source - biomass burning (BBOA) - was found in all the samples (average values 7% RS; 12% UB; 0.3 μg OC m-3), but this component was substantially contributing to OA only when the sampling sites were under influence of regional air mass circulation (REG.). Three secondary organic aerosol (SOA) components (describing overall 60% of the variance) were observed in the urban ambient PM1. Products of isoprene oxidation (SOA ISO) - i.e. 2-methylglyceric acid, C5 alkene triols and 2-methyltetrols - showed the highest abundance at both sites when the city was under influence of inland air masses. The overall concentrations of SOA ISO were similar at both sites (0.4 and 0.3 μg m-3, or 16% and 7%, at UB and RS, respectively). By contrast, a SOA biogenic component attributed to α-pinene oxidation (SOA BIO PIN) presented average concentrations of 0.5 μg m-3 at UB (24% of OA) and 0.2 μg m-3 at RS (7%), respectively, suggesting that this SOA component did not impact the two monitoring sites at the same level. A clear anti-correlation was observed between SOA ISO and SOA PIN during nucleation days, surprisingly suggesting that some of the growth of urban freshly nucleating particles may be driven by biogenic α-pinene oxidation products but inhibited by isoprene organic compounds. A third SOA component was formed by a mixture of aged anthropogenic and biogenic secondary organic compounds (SOA Aged) that accumulated under stagnant atmospheric conditions, contributing for 12% to OA at RS (0.4 μg OC m-3) and for 18% at UB (0.4 μg OC m-3). A sixth component, formed by C7-C9 dicarboxylic acids and detected especially during daytime, was called "urban oxygenated organic aerosol" (OOA Urban) due to its high abundance at urban RS (23%; 0.8 μg OCm-3) vs. UB (10%; 0.2 μg OCm-3), with a well-defined daytime maximum. This temporal trend and geographical differentiation suggests that local anthropogenic sources were determining this component. However, the changes of these organic molecules were also influenced by the air mass trajectories, indicating that atmospheric conditions have an influence on this component, although the specific origin on this component remains unclear. It points to a secondary organic component driven by primary urban sources including cooking and traffic (mainly gasoline) activities.

Source apportionment of submicron organic aerosol at an urban background and a road site in Barcelona, Spain

NASA Astrophysics Data System (ADS)

Alier, M.; van Drooge, B. L.; Dall'Osto, M.; Querol, X.; Grimalt, J. O.; Tauler, R.

2013-04-01

This study investigates the contribution of potential sources to the sub-micron (PM1) organic aerosol (OA) simultaneously detected at an urban background (UB) and a road site (RS) in Barcelona during the 30 days of the intensive field campaign of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies, September-October 2010). 103 filters at 12 h sampling time resolution were collected at both sites. Thirty-six neutral and polar organic compounds of known emission sources and photo-chemical transformation processes were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). The concentrations of the trace chemical compounds analyzed are herein presented and discussed. Additionally, OA source apportionment was performed by Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) and six OA components were identified at both sites: two were of primary anthropogenic OA origin, three of secondary OA origin while a sixth one was not clearly defined. Primary organics from emissions of local anthropogenic activities (Urban primary organic aerosol, Urban POA) contributed for 43% (1.5 μg OC m-3) and 18% (0.4 μg OC m-3) to OA in RS and UB, respectively. A secondary primary source - biomass burning (BBOA) - was found in all the samples (average values 7% RS; 12% UB; 0.3 μg OC m-3), but this component was substantially contributing to OA only when the sampling sites were under influence of regional air mass circulation. Three Secondary Organic Aerosol (SOA) components (describing overall 60% of the variance) were observed in the urban ambient PM1. Products of isoprene oxidation (SOA ISO), i.e. 2-methylglyceric acid, C5 alkene triols and 2-methyltetrols, showed the highest abundance at both sites when the city was under influence of inland air masses. The overall concentrations of SOA ISO were similar at both sites (0.4 and 0.3 μg m-3, 16% and 7%, at UB and RS, respectively). By contrast, a SOA biogenic component attributed to α-pinene oxidation (SOA BIO PIN) presented average concentrations of 0.5 μg m-3 at UB (24% of OA) and 0.2 μg m-3 at RS (7%), respectively, suggesting that this SOA component did not impact the two monitoring site at the same level. A clear anti correlation was observed between SOA ISO and SOA PIN during nucleation days, surprisingly suggesting that some of the growth of urban freshly nucleating particles may be driven by biogenic α-pinene oxidation products but inhibited by isoprene organic compounds. A third SOA component was formed by a mixture of aged anthropogenic and biogenic secondary organic compounds (Aged SOA) that accumulated under stagnant atmospheric conditions, contributing for 12% to OA at RS (0.4 μg OC m-3) and for 18% at UB (0.4 μg OC m-3). A sixth component, formed by C7-C9 dicarboxylic acids and detected especially during daytime, was called "urban oxygenated organic aerosol" (Urban OOA) due to its high abundance in urban RS (23%; 0.8 μg OC m-3) vs. UB (10%; 0.2 μg OC m-3), with a well-defined daytime maximum. This temporal trend and geographical differentiation suggests that local anthropogenic sources were determining this component. However, the changes of these organic molecules were also influenced by the air mass trajectories, indicating that atmospheric conditions had an influence on this component although the specific origin on this component remains unclear. It points to a secondary organic component driven by primary urban sources including cooking and traffic (mainly gasoline) activities.

Organic composition and source apportionment of fine aerosol at Monterrey, Mexico, based on organic markers

NASA Astrophysics Data System (ADS)

Mancilla, Y.; Mendoza, A.; Fraser, M. P.; Herckes, P.

2016-01-01

Primary emissions from anthropogenic and biogenic sources as well as secondary formation are responsible for the pollution levels of ambient air in major urban areas. These sources release fine particles into the air that negatively impact human health and the environment. Organic molecular markers, which are compounds that are unique to specific PM2.5 sources, can be utilized to identify the major emission sources in urban areas. In this study, 43 representative PM2.5 samples, for both daytime and nighttime periods, were built from individual samples collected in an urban site of the Monterrey metropolitan area (MMA) during the spring and fall of 2011 and 2012. The samples were analyzed for organic carbon, elemental carbon, and organic molecular markers. Several diagnostic tools were employed for the preliminary identification of emission sources. Organic compounds for eight compound classes were quantified. The n-alkanoic acids were the most abundant, followed by n-alkanes, wood smoke markers, and levoglucosan/alkenoic acids. Polycyclic aromatic hydrocarbons (PAHs) and hopanes were less abundant. The carbon preference index (0.7-2.6) for n-alkanes indicates a major contribution of anthropogenic and mixed sources during the fall and the spring, respectively. Hopanes levels confirmed the contribution from gasoline and diesel engines. In addition, the contribution of gasoline and diesel vehicle exhaust was confirmed and identified by the PAH concentrations in PM2.5. Diagnostic ratios of PAHs showed emissions from burning coal, wood, biomass, and other fossil fuels. The total PAHs and elemental carbon were correlated (r2 = 0.39-0.70) across the monitoring periods, reinforcing that motor vehicles are the major contributors of PAHs. Cholesterol levels remained constant during the spring and fall, showing evidence of the contribution of meat-cooking operations, while the isolated concentrations of levoglucosan suggested occasional biomass burning events. Finally, source attribution results obtained using the CMB (chemical mass balance) model indicate that emissions from motor vehicle exhausts are the most important, accounting for the 64 % of the PM2.5, followed by meat-cooking operations with 31 % The vegetative detritus and biomass burning had the smallest contribution (2.2 % of the PM2.5). To our knowledge, this is only the second study to explore the organic composition and source apportionment of fine organic aerosol based on molecular markers in Mexico and the first for the MMA. Particularly molecular marker were quantified by solvent extraction with dichloromethane, derivatization, and gas chromatography with mass spectrometry (GC/MS).

PM2.5 Source Apportionment: Reconciling Receptor Models for U.S. Nonurban and Urban Long-Term Networks.

PubMed

Chen, L-W Antony; Watson, John G; Chow, Judith C; DuBois, Dave W; Herschberger, Lisa

2011-11-01

Chemical mass balance (CMB) and trajectory receptor models were applied to speciated particulate matter with aerodynamic diameter ≤2.5 μm (PM 2.5 ) measurements from Speciation Trends Network (STN; part of the Chemical Speciation Network [CSN]) and Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network across the state of Minnesota as part of the Minnesota PM 2.5 Source Apportionment Study (MPSAS). CMB equations were solved by the Unmix, positive matrix factorization (PMF), and effective variance (EV) methods, giving collective source contribution and uncertainty estimates. Geological source profiles developed from local dust materials were either incorporated into the EV-CMB model or used to verify factors derived from Unmix and PMF. Common sources include soil dust, calcium (Ca)-rich dust, diesel and gasoline vehicle exhausts, biomass burning, secondary sulfate, and secondary nitrate. Secondary sulfate and nitrate aerosols dominate PM 2.5 mass (50-69%). Mobile sources outweigh area sources at urban sites, and vice versa at rural sites due to traffic emissions. Gasoline and diesel contributions can be separated using data from the STN, despite significant uncertainties. Major differences between MPSAS and earlier studies on similar environments appear to be the type and magnitude of stationary sources, but these sources are generally minor (<7%) in this and other studies. Ensemble back-trajectory analysis shows that the lower Midwestern states are the predominant source region for secondary ammoniated sulfate in Minnesota. It also suggests substantial contributions of biomass burning and soil dust from out-of-state on occasions, although a quantitative separation of local and regional contributions was not achieved in the current study. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for a summary of input data, Unmix and PMF factor profiles, and additional maps. [Box: see text].

Chemical composition and source apportionment of size fractionated particulate matter in Cleveland, Ohio, USA.

PubMed

Kim, Yong Ho; Krantz, Q Todd; McGee, John; Kovalcik, Kasey D; Duvall, Rachelle M; Willis, Robert D; Kamal, Ali S; Landis, Matthew S; Norris, Gary A; Gilmour, M Ian

2016-11-01

The Cleveland airshed comprises a complex mixture of industrial source emissions that contribute to periods of non-attainment for fine particulate matter (PM 2.5 ) and are associated with increased adverse health outcomes in the exposed population. Specific PM sources responsible for health effects however are not fully understood. Size-fractionated PM (coarse, fine, and ultrafine) samples were collected using a ChemVol sampler at an urban site (G.T. Craig (GTC)) and rural site (Chippewa Lake (CLM)) from July 2009 to June 2010, and then chemically analyzed. The resulting speciated PM data were apportioned by EPA positive matrix factorization to identify emission sources for each size fraction and location. For comparisons with the ChemVol results, PM samples were also collected with sequential dichotomous and passive samplers, and evaluated for source contributions to each sampling site. The ChemVol results showed that annual average concentrations of PM, elemental carbon, and inorganic elements in the coarse fraction at GTC were ∼2, ∼7, and ∼3 times higher than those at CLM, respectively, while the smaller size fractions at both sites showed similar annual average concentrations. Seasonal variations of secondary aerosols (e.g., high NO 3 - level in winter and high SO 4 2- level in summer) were observed at both sites. Source apportionment results demonstrated that the PM samples at GTC and CLM were enriched with local industrial sources (e.g., steel plant and coal-fired power plant) but their contributions were influenced by meteorological conditions and the emission source's operation conditions. Taken together the year-long PM collection and data analysis provides valuable insights into the characteristics and sources of PM impacting the Cleveland airshed in both the urban center and the rural upwind background locations. These data will be used to classify the PM samples for toxicology studies to determine which PM sources, species, and size fractions are of greatest health concern. Copyright © 2016 Elsevier Ltd. All rights reserved.

PM2.5 pollution from household solid fuel burning practices in Central India: 2. Application of receptor models for source apportionment.

PubMed

Matawle, Jeevan Lal; Pervez, Shamsh; Deb, Manas Kanti; Shrivastava, Anjali; Tiwari, Suresh

2018-02-01

USEPA's UNMIX, positive matrix factorization (PMF) and effective variance-chemical mass balance (EV-CMB) receptor models were applied to chemically speciated profiles of 125 indoor PM 2.5 measurements, sampled longitudinally during 2012-2013 in low-income group households of Central India which uses solid fuels for cooking practices. Three step source apportionment studies were carried out to generate more confident source characterization. Firstly, UNMIX6.0 extracted initial number of source factors, which were used to execute PMF5.0 to extract source-factor profiles in second step. Finally, factor analog locally derived source profiles were supplemented to EV-CMB8.2 with indoor receptor PM 2.5 chemical profile to evaluate source contribution estimates (SCEs). The results of combined use of three receptor models clearly describe that UNMIX and PMF are useful tool to extract types of source categories within small receptor dataset and EV-CMB can pick those locally derived source profiles for source apportionment which are analog to PMF-extracted source categories. The source apportionment results have also shown three fold higher relative contribution of solid fuel burning emissions to indoor PM 2.5 compared to those measurements reported for normal households with LPG stoves. The previously reported influential source marker species were found to be comparatively similar to those extracted from PMF fingerprint plots. The comparison between PMF and CMB SCEs results were also found to be qualitatively similar. The performance fit measures of all three receptor models were cross-verified and validated and support each other to gain confidence in source apportionment results.

Source attribution of aerosol size distributions and model evaluation using Whistler Mountain measurements and GEOS-Chem-TOMAS simulations

NASA Astrophysics Data System (ADS)

D'Andrea, S. D.; Ng, J. Y.; Kodros, J. K.; Atwood, S. A.; Wheeler, M. J.; Macdonald, A. M.; Leaitch, W. R.; Pierce, J. R.

2016-01-01

Remote and free-tropospheric aerosols represent a large fraction of the climatic influence of aerosols; however, aerosol in these regions is less characterized than those polluted boundary layers. We evaluate aerosol size distributions predicted by the GEOS-Chem-TOMAS global chemical transport model with online aerosol microphysics using measurements from the peak of Whistler Mountain, British Columbia, Canada (2182 m a.s.l., hereafter referred to as Whistler Peak). We evaluate the model for predictions of aerosol number, size, and composition during periods of free-tropospheric (FT) and boundary-layer (BL) influence at "coarse" 4° × 5° and "nested" 0.5° × 0.667° resolutions by developing simple FT/BL filtering techniques. We find that using temperature as a proxy for upslope flow (BL influence) improved the model-measurement comparisons. The best threshold temperature was around 2 °C for the coarse simulations and around 6 °C for the nested simulations, with temperatures warmer than the threshold indicating boundary-layer air. Additionally, the site was increasingly likely to be in cloud when the measured relative humidity (RH) was above 90 %, so we do not compare the modeled and measured size distributions during these periods. With the inclusion of these temperature and RH filtering techniques, the model-measurement comparisons improved significantly. The slope of the regression for N80 (the total number of particles with particle diameter, Dp, > 80 nm) in the nested simulations increased from 0.09 to 0.65, R2 increased from 0.04 to 0.46, and log-mean bias improved from 0.95 to 0.07. We also perform simulations at the nested resolution without Asian anthropogenic emissions and without biomass-burning emissions to quantify the contribution of these sources to aerosols at Whistler Peak (through comparison with simulations with these emissions on). The long-range transport of Asian anthropogenic aerosol was found to be significant throughout all particle number concentrations, and increased N80 by more than 50 %, while decreasing the number of smaller particles because of suppression of new-particle formation and enhanced coagulation sink. Similarly, biomass burning influenced Whistler Peak during summer months, with an increase in N80 exceeding 5000 cm-3. Occasionally, Whistler Peak experienced N80 > 1000 cm-3 without significant influence from Asian anthropogenic or biomass-burning aerosol. Air masses were advected at low elevations through forested valleys during times when temperature and downwelling insolation were high, ideal conditions for formation of large sources of low-volatility biogenic secondary organic aerosol (SOA). This condensable material increased particle growth and hence N80. The low-cost filtering techniques and source apportionment used in this study can be used in other global models to give insight into the sources and processes that shape the aerosol at mountain sites, leading to a better understanding of mountain meteorology and chemistry.

Source attribution of aerosol size distributions and model evaluation using Whistler Mountain measurements and GEOS-Chem-TOMAS simulations

NASA Astrophysics Data System (ADS)

D'Andrea, S. D.; Ng, J. Y.; Kodros, J. K.; Atwood, S. A.; Wheeler, M. J.; Macdonald, A. M.; Leaitch, W. R.; Pierce, J. R.

2015-09-01

Remote and free tropospheric aerosols represent a large fraction of the climatic influence of aerosols; however, aerosol in these regions is less characterized than those polluted boundary layers. We evaluate aerosol size distributions predicted by the GEOS-Chem-TOMAS global chemical transport model with online aerosol microphysics using measurements from the peak of Whistler Mountain, BC, Canada (2182 m a.s.l.). We evaluate the model for predictions of aerosol number, size and composition during periods of free tropospheric (FT) and boundary-layer (BL) influence at "coarse" 4° × 5° and "nested" 0.5° × 0.667° resolutions by developing simple FT/BL filtering techniques. We find that using temperature as a proxy for upslope flow (BL influence) improved the model measurement comparisons. The best threshold temperature was around 2 °C for the coarse simulations and around 6 °C for the nested simulations, with temperatures warmer than the threshold indicating boundary-layer air. Additionally, the site was increasingly likely to be in-cloud when the measured RH was above 90 %, so we do not compare the modeled and measured size distributions during these periods. With the inclusion of these temperature and RH filtering techniques, the model-measurement comparisons improved significantly. The slope of the regression for N80 (the total number of particles with particle diameter, Dp > 80 nm) in the nested simulations increased from 0.09 to 0.65, R2 increased from 0.04 to 0.46, and log-mean bias improved from 0.95 to 0.07. We also perform simulations at the nested resolution without Asian anthropogenic (AA) emissions and without biomass-burning (BB) emissions to quantify the contribution of these sources to aerosols at Whistler Peak (through comparison with simulations with these emissions on). The long-range transport of AA aerosol was found to be significant throughout all particle number concentrations, and increased the number of particles larger than 80 nm (N80) by more than 50 %, while decreasing the number of smaller particles because of suppression of new-particle formation and enhanced coagulation sink. Similarly, BB influenced Whistler Peak during summer months, with an increase in N80 exceeding 5000 cm-3. Occasionally, Whistler Peak experienced N80 > 1000 cm-3 without significant influence from AA or BB aerosol. Air masses were advected at low elevations through forested valleys during times when temperature and downwelling insolation were high, ideal conditions for formation of large sources of low-volatility biogenic secondary organic aerosol (SOA). This condensable material increased particle growth and hence N80. The low-cost filtering techniques and source apportionment used in this study can be used in other global models to give insight into the sources and processes that shape the aerosol at mountain sites, leading to a better understanding of mountain meteorology and chemistry.

Chemical characteristics and source of size-fractionated atmospheric particle in haze episode in Beijing

NASA Astrophysics Data System (ADS)

Tan, Jihua; Duan, Jingchun; Zhen, Naijia; He, Kebin; Hao, Jiming

2016-01-01

The abundance, behavior, and source of chemical species in size-fractionated atmospheric particle were studied with a 13-stage low pressure impactor (ELPI) during high polluted winter episode in Beijing. Thirty three elements (Al, Ca, Fe, K, Mg, Na, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, and Pb) and eight water soluble ions (Cl-, NO3-, SO42 -, NH4+, Na+, K+, Ca2 +, and Mg2 +) were determined by ICP/MS and IC, respectively. The size distribution of TC (OC + EC) was reconstructed. Averagely, 51.5 ± 5.3% and 74.1 ± 3.7% of the total aerosol mass was distributed in the sub-micron (PM1) and fine particle (PM2.5), respectively. A significant shift to larger fractions during heavy pollution episode was observed for aerosol mass, NH4+, SO42 -, NO3-, K, Fe, Cu, Zn, Cd, and Pb. The mass size distributions of NH4+, SO42 -, NO3-, and K were dominated by accumulation mode. Size distributions of elements were classified into four main types: (I) elements were enriched within the accumulation mode (< 1 μm, Ge, Se, Ag, Sn, Sb, Cs, Hg, Ti, and Pb); (II) those mass (K, Cr, Mn, Cu, Zn, As, Mo, and Cd) was resided mainly within the accumulation mode, ranged from 1 to 2 μm; (III) Na, V, Co, Ni, and Ga were distributed among fine, intermediate, and coarse modes; and (IV) those which were mainly found within particles larger than 2.7 μm (Al, Mg, Si, Ca, Sc, Tl, Fe, Sr, Zr, and Ba). [H+]cor showed an accumulation mode at 600-700 nm and the role of Ca2 + should be fully considered in the estimation of acidity. The acidity in accumulation mode particles suggested that generally gaseous NH3 was not enough to neutralize sulfate completely. PMF method was applied for source apportionment of elements combined with water soluble ions. Dust, vehicle, aged coal combustion, and sea salt were identified, and the size resolved source apportionments were discussed. Aged coal combustion was the important source of fine particles and dust contributed most to coarse particle.

A Handbook for Determining the Sources of PCB Contamination in Sediments

DTIC Science & Technology

2012-10-01

identifying sources for initial source control to later use for remedial cost apportionment . Often, forensic investigations are successfully used to...alteration processes, source apportionment can be difficult. For instance, one can easily imagine an onshore spill or source of PCB oil that results in a...the use of Aroclor analyses for identifying contamination sources to only fresh samples (for example, PCB oils or soils with freshly spilled PCB

Measurements of the aerosol chemical composition and mixing state in the Po Valley using multiple spectroscopic techniques

NASA Astrophysics Data System (ADS)

Decesari, S.; Allan, J.; Plass-Duelmer, C.; Williams, B. J.; Paglione, M.; Facchini, M. C.; O'Dowd, C.; Harrison, R. M.; Gietl, J. K.; Coe, H.; Giulianelli, L.; Gobbi, G. P.; Lanconelli, C.; Carbone, C.; Worsnop, D.; Lambe, A. T.; Ahern, A. T.; Moretti, F.; Tagliavini, E.; Elste, T.; Gilde, S.; Zhang, Y.; Dall'Osto, M.

2014-04-01

The use of co-located multiple spectroscopic techniques can provide detailed information on the atmospheric processes regulating aerosol chemical composition and mixing state. So far, field campaigns heavily equipped with aerosol mass spectrometers have been carried out mainly in large conurbations and in areas directly affected by their outflow, whereas lesser efforts have been dedicated to continental areas characterized by a less dense urbanization. We present here the results obtained in San Pietro Capofiume, which is located in a sparsely inhabited sector of the Po Valley, Italy. The experiment was carried out in summer 2009 in the framework of the EUCAARI project ("European Integrated Project on Aerosol, Cloud Climate Aerosol Interaction"). For the first time in Europe, six state-of-the-art techniques were used in parallel: (1) on-line TSI aerosol time-of-flight mass spectrometer (ATOFMS), (2) on-line Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS), (3) soot particle aerosol mass spectrometer (SP-AMS), (4) on-line high resolution time-of-flight mass spectrometer-thermal desorption aerosol gas chromatograph (HR-ToFMS-TAG), (5) off-line twelve-hour resolution proton nuclear magnetic resonance (H-NMR) spectroscopy, and (6) chemical ionization mass spectrometry (CIMS) for the analysis of gas-phase precursors of secondary aerosol. Data from each aerosol spectroscopic method were analysed individually following ad-hoc tools (i.e. PMF for AMS, Art-2a for ATOFMS). The results obtained from each techniques are herein presented and compared. This allows us to clearly link the modifications in aerosol chemical composition to transitions in air mass origin and meteorological regimes. Under stagnant conditions, atmospheric stratification at night and early morning hours led to the accumulation of aerosols produced by anthropogenic sources distributed over the Po Valley plain. Such aerosols include primary components such as black carbon (BC), only partly internally mixed with secondary semivolatile compounds such as ammonium nitrate and amines. Other organic components originating from anthropogenic sources at night include monocarboxylic acids which correspond to an AMS factor analogous to the "cooking" organic aerosol (COA) already identified in urban areas. In daytime, enhanced mixing in the planetary boundary layer (PBL) along with increasing temperature determined dramatic changes in aerosol composition caused by the evaporation of semivolatile components and by the entrainment of aged aerosols transported downwards from residual layers. In other words, the entrainment of aged air masses is responsible for the accumulation of low-volatility oxygenated organic aerosol (LV-OOAs) and also for the recycling of primary species such as black carbon. The LV-OOA concentrations were shown to correlate to the simple meteorological tracers of humid PBL air produced by daytime convection over land areas. In particular, both PMF-AMS and PMF-NMR could resolve two components of LV-OOA: one from long-range transport from Central Europe, the second from recirculated PBL air from the Po Valley. According to organic aerosol source apportionment by PMF-AMS, anthropogenic aerosols accumulating in the lower layers overnight accounted for 38% of organic aerosol mass on average, another 21% was accounted for by aerosols recirculated in residual layers but still originating in North Italy, while a substantial fraction (41%) was due to the most aged aerosols imported from transalpine areas. Overall, the deployment of six state-of-the-art spectrometric techniques provided a comprehensive picture of the nature and source contributions of aerosols and aerosol precursors at a European rural site with unprecedented level of details.

Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Niu, Hewen; Kang, Shichang; Wang, Hailong; Zhang, Rudong; Lu, Xixi; Qian, Yun; Paudyal, Rukumesh; Wang, Shijin; Shi, Xiaofei; Yan, Xingguo

2018-05-01

Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32 µg m-3, respectively. Although the annual mean OC / EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a. s. l. ) of Mt. Yulong. Strong photochemical reactions and local tourism activities were likely the main factors inducing high OC / EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m2 g-1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol-climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 %) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.

Receptor modeling of PM2.5, PM10 and TSP in different seasons and long-range transport analysis at a coastal site of Tianjin, China.

PubMed

Kong, Shaofei; Han, Bin; Bai, Zhipeng; Chen, Li; Shi, Jianwu; Xu, Zhun

2010-09-15

Atmospheric particulate matter (PM(2.5), PM(10) and TSP) were sampled synchronously during three monitoring campaigns from June 2007 to February 2008 at a coastal site in TEDA of Tianjin, China. Chemical compositions including 19 elements, 6 water-solubility ions, organic and elemental carbon were determined. principle components analysis (PCA) and chemical mass balance modeling (CMB) were applied to determine the PM sources and their contributions with the assistance of NSS SO(4)(2)(-), the mass ratios of NO(3)(-) to SO(4)(2)(-) and OC to EC. Air mass backward trajectory model was compared with source apportionment results to evaluate the origin of PM. Results showed that NSS SO(4)(2)(-) values for PM(2.5) were 2147.38, 1701.26 and 239.80 ng/m(3) in summer, autumn and winter, reflecting the influence of sources from local emissions. Most of it was below zero in summer for PM(10) indicating the influence of sea salt. The ratios of NO(3)(-) to SO(4)(2)(-) was 0.19 for PM(2.5), 0.18 for PM(10) and 0.19 for TSP in winter indicating high amounts of coal consumed for heating purpose. Higher OC/EC values (mostly larger than 2.5) demonstrated that secondary organic aerosol was abundant at this site. The major sources were construction activities, road dust, vehicle emissions, marine aerosol, metal manufacturing, secondary sulfate aerosols, soil dust, biomass burning, some pharmaceutics industries and fuel-oil combustion according to PCA. Coal combustion, marine aerosol, vehicular emission and soil dust explained 5-31%, 1-13%, 13-44% and 3-46% for PM(2.5), PM(10) and TSP, respectively. Backward trajectory analysis showed air parcels originating from sea accounted for 39% in summer, while in autumn and winter the air parcels were mainly related to continental origin. Copyright 2010 Elsevier B.V. All rights reserved.

Studying organic aerosols during bonfire night in Manchester: ME-2 source apportionment

NASA Astrophysics Data System (ADS)

Reyes Villegas, Ernesto; Allan, James

2016-04-01

Over the past decade, there has been an increasing interest in short-term events that negatively affect air quality (Zhao et al. 2014) such as bonfires and fireworks. In general, during these episodes, high particulate matter concentrations drop within 24 hrs; however, it is the fine fraction that dominates the emissions, known to have a potentially negative impact on air quality, thus the impact of bonfires/fireworks on air quality must be considered. Aerosols and gases were measured using a variety of instruments at The University of Manchester, sampling atmospheric emissions on Bonfire night, 5 November, one week before and one week later, in 2013 and 2014. The Multilinear Engine (ME-2) factorization tool was used through the recently developed source finder interface (SoFi, Canonaco et al. 2013) to identify sources of organic aerosols (OA) sampled with an Aerosol Mass Spectrometer (AMS). ME-2 identified five sources: solid fuel OA (SFOA), hydrocarbon like OA (HOA), cooking OA (COA), semi-volatile (SVOOA) and low volatility (LVOOA) during both years. In 2014, air pollutant concentrations were particularly high, with the highest SFOA concentrations being 20 μgm-3 at 20:30 hrs. when fireworks from different parks in Manchester were launched. Black carbon (BC) concentrations started increasing before the fireworks, around 18:00 hrs; these concentrations are representative of bonfire emissions. However, traffic emissions may be contributing to BC here; further work will be done to differentiate traffic emissions from solid fuel emissions. By analysing daily aerosol concentrations according to DEFRA's Daily Air Quality Index, it is possible to observe that in 2014, PM2.5 concentrations were considered to be high (65 μgm-3) while in 2013, PM2.5 concentrations were considered low (12 μgm-3); in the case of BBOA, concentrations ranged from 2.9 μgm-3 in 2014 to 0.65 μgm-3 in 2013. The discrepancy between these studies is mainly a result of different meteorological conditions: 5°C in 2014; 12°C in 2013. For NH4NO3, a range of 1.5-2.9 for the ratio of concentrations NO+/NO+2 (m/z ratio of 30:46) has previously been reported (Fry et al. 2009) while the ratio for organic nitrate is much higher, with values of 10-15 (Hao et al. 2014). In this study, a ratio of 9.5 was observed on bonfire night and a ratio of 3.5 was observed during episodes without bonfire/fireworks emissions. This study shows OA source apportionment on bonfire night where significant SFOA emissions are present, suggesting that high concentrations are not only attributed to bonfires/fireworks emissions but also to meteorological conditions. Organic nitrate was identified during bonfire night suggesting a nighttime chemistry with anthropogenic oxidants. This analysis may provide vital information to strengthen legislation as well as to support health studies in order to improve air quality in the UK. Canonaco, F. et al. Atmos Meas Tech. 6, 3649-3661, 2013. Fry, J. et al. Atmos. Chem. Phys. 9, 1431-1449, 2009. Hao, L. Atmos. Chem. Phys., 14, 13483-13495, 2014. Zhao, S. et al. Atmospheric Pollution Research. 5, 335-343, 2014.

Heating Rate of Light Absorbing Aerosols: Time-Resolved Measurements, the Role of Clouds, and Source Identification.

PubMed

Ferrero, Luca; Močnik, Griša; Cogliati, Sergio; Gregorič, Asta; Colombo, Roberto; Bolzacchini, Ezio

2018-03-20

Light absorbing aerosols (LAA) absorb sunlight and heat the atmosphere. This work presents a novel methodology to experimentally quantify the heating rate (HR) induced by LAA into an atmospheric layer. Multiwavelength aerosol absorption measurements were coupled with spectral measurements of the direct, diffuse and surface reflected radiation to obtain highly time-resolved measurements of HR apportioned in the context of LAA species (black carbon, BC; brown carbon, BrC; dust), sources (fossil fuel, FF; biomass burning, BB), and as a function of cloudiness. One year of continuous and time-resolved measurements (5 min) of HR were performed in the Po Valley. We experimentally determined (1) the seasonal behavior of HR (winter 1.83 ± 0.02 K day -1 ; summer 1.04 ± 0.01 K day -1 ); (2) the daily cycle of HR (asymmetric, with higher values in the morning than in the afternoon); (3) the HR in different sky conditions (from 1.75 ± 0.03 K day -1 in clear sky to 0.43 ± 0.01 K day -1 in complete overcast); (4) the apportionment to different sources: HR FF (0.74 ± 0.01 K day -1 ) and HR BB (0.46 ± 0.01 K day -1 ); and (4) the HR of BrC (HR BrC : 0.15 ± 0.01 K day -1 , 12.5 ± 0.6% of the total) and that of BC (HR BC : 1.05 ± 0.02 K day -1 ; 87.5 ± 0.6% of the total).

Development and characterization of an aircraft aerosol time-of-flight mass spectrometer.

PubMed

Pratt, Kerri A; Mayer, Joseph E; Holecek, John C; Moffet, Ryan C; Sanchez, Rene O; Rebotier, Thomas P; Furutani, Hiroshi; Gonin, Marc; Fuhrer, Katrin; Su, Yongxuan; Guazzotti, Sergio; Prather, Kimberly A

2009-03-01

Vertical and horizontal profiles of atmospheric aerosols are necessary for understanding the impact of air pollution on regional and global climate. To gain further insight into the size-resolved chemistry of individual atmospheric particles, a smaller aerosol time-of-flight mass spectrometer (ATOFMS) with increased data acquisition capabilities was developed for aircraft-based studies. Compared to previous ATOFMS systems, the new instrument has a faster data acquisition rate with improved ion transmission and mass resolution, as well as reduced physical size and power consumption, all required advances for use in aircraft studies. In addition, real-time source apportionment software allows the immediate identification and classification of individual particles to guide sampling decisions while in the field. The aircraft (A)-ATOFMS was field-tested on the ground during the Study of Organic Aerosols in Riverside, CA (SOAR) and aboard an aircraft during the Ice in Clouds Experiment-Layer Clouds (ICE-L). Initial results from ICE-L represent the first reported aircraft-based single-particle dual-polarity mass spectrometry measurements and provide an increased understanding of particle mixing state as a function of altitude. Improved ion transmission allows for the first single-particle detection of species out to approximately m/z 2000, an important mass range for the detection of biological aerosols and oligomeric species. In addition, high time resolution measurements of single-particle mixing state are demonstrated and shown to be important for airborne studies where particle concentrations and chemistry vary rapidly.

Fine particulate matter associated with monsoonal effect and the responses of biomass fire hotspots in the tropical environment

NASA Astrophysics Data System (ADS)

Khan, M. F.; Latif, M. T.; Saw, W. H.; Amil, N.; Nadzir, M. S. M.; Sahani, M.; Tahir, N. M.; Chung, J. X.

2015-08-01

The health implications of PM2.5 in tropical regions of Southeast Asia are significant as PM2.5 can pose serious health concerns. PM2.5 is strongly influenced by the monsoon. We quantitatively characterize the health risks posed to human populations by selected heavy metals in PM2.5. Monsoonal effects as well as factors influencing the sources of PM2.5 were also determined. Apportionment analysis of PM2.5 was undertaken using US EPA positive matrix factorization (PMF) 5.0 and a mass closure model. Overall, 48 % of the samples exceeded the World Health Organization (WHO) 24 h guideline. The mass closure model identified four sources of PM2.5: (a) mineral matter (MIN) (35 %), (b) secondary inorganic aerosol (SIA) (11 %), (c) sea salt (SS) (7 %), (d) trace elements (TE) (2 %) and (e) undefined (UD) (45 %). PMF 5.0 identified five potential sources and motor vehicle emissions and biomass burning were dominant followed by marine and sulfate aerosol, coal burning, nitrate aerosol, and mineral and road dust. The non-carcinogenic risk level for four selected metals (Pb, As, Cd and Ni) in PM2.5 and in the identified major sources by PMF > 5.0, with respect to inhalation follows the order of PM2.5 > coal burning > motor vehicle emissions/biomass burning > mineral/road dust. The lifetime cancer risk follows the order of As > Ni > Pb > Cd for mineral/road dust, coal burning and overall of PM2.5 concentration and As > Pb > Ni > Cd for motor vehicle/biomass burning. Overall, the associated cancer risk posed by the exposure of toxic metals in PM2.5 is three to four in 1 000 000 people in this location.

Source apportionment revisited for long-term measurements of fine aerosol trace elements at two locations in southern Norway

NASA Astrophysics Data System (ADS)

Maenhaut, Willy

2018-02-01

Five-year-long (1991-1996) aerosol trace element data sets for the fine (PM2) size fraction from the sites of Birkenes and Skreådalen in southern Norway were reanalysed by US EPA positive matrix factorization PMF5 in order to assess the sources and their contribution to the PM2 aerosol. The data sets contained the concentrations of the particulate mass (PM), black carbon (BC) and 21 elements in over 700 samples for each of the two sites. The PM was obtained from weighing with a microbalance and BC was determined with a light reflectance technique. The data for the elements were obtained by a combination of particle-induced X-ray emission and instrumental neutron activation analysis. Eight source factors were retained for each site, i.e., (i) secondary sulfate, which accounted for around 40% of the average measured PM2 mass, (ii) wood burning, with BC, K, Zn and As, which accounted for about 17%, (iii) an iodine factor (with also Br and Se), which is probably related to a marine biogenic source and was responsible for about 6.5%, (iv) aged sea salt with Na, Mg, Cl and Ca, but heavily depleted in Cl; (v) a crustal factor containing Al, Si, Ca, Ti and Fe; (vi) a heavy oil burning factor with V and Ni in a ratio of 3-4; (vii) a general pollution factor (with Cu, Zn, As, Se, Sb and Pb), and (viii) an almost pure manganese factor, which is attributed to Mn and FeMn industries in southern Norway. The results were substantially different from those of an earlier PMF analysis, in which use was made of PMF2.

Guidance Document for PMF Applications with the Multilinear Engine

EPA Science Inventory

This document serves as a guide for users of the Multilinear Engine version 2 (ME-2) for source apportionment applications utilizing positive matrix factorization (PMF). It aims to educate experienced source apportionment analysts on available ME rotational tools and provides gui...

Source apportionment of PM2.5 organic carbon in the San Joaquin Valley using monthly and daily observations and meteorological clustering.

PubMed

Skiles, Matthew J; Lai, Alexandra M; Olson, Michael R; Schauer, James J; de Foy, Benjamin

2018-06-01

Two hundred sixty-three fine particulate matter (PM 2.5 ) samples collected on 3-day intervals over a 14-month period at two sites in the San Joaquin Valley (SJV) were analyzed for organic carbon (OC), elemental carbon (EC), water soluble organic carbon (WSOC), and organic molecular markers. A unique source profile library was applied to a chemical mass balance (CMB) source apportionment model to develop monthly and seasonally averaged source apportionment results. Five major OC sources were identified: mobile sources, biomass burning, meat smoke, vegetative detritus, and secondary organic carbon (SOC), as inferred from OC not apportioned by CMB. The SOC factor was the largest source contributor at Fresno and Bakersfield, contributing 44% and 51% of PM mass, respectively. Biomass burning was the only source with a statistically different average mass contribution (95% CI) between the two sites. Wintertime peaks of biomass burning, meat smoke, and total OC were observed at both sites, with SOC peaking during the summer months. Exceptionally strong seasonal variation in apportioned meat smoke mass could potentially be explained by oxidation of cholesterol between source and receptor and trends in wind transport outlined in a Residence Time Analysis (RTA). Fast moving nighttime winds prevalent during warmer months caused local emissions to be replaced by air mass transported from the San Francisco Bay Area, consisting of mostly diluted, oxidized concentrations of molecular markers. Good agreement was observed between SOC derived from the CMB model and from non-biomass burning WSOC mass, suggesting the CMB model is sufficiently accurate to assist in policy development. In general, uncertainty in monthly mass values derived from daily CMB apportionments were lower than that of CMB results produced with monthly marker composites, further validating daily sampling methodologies. Strong seasonal trends were observed for biomass and meat smoke OC apportionment, and monthly mass averages had lowest uncertainty when derived from daily CMB apportionments. Copyright © 2018 Elsevier Ltd. All rights reserved.

A combined approach for the evaluation of a volatile organic compound emissions inventory.

PubMed

Choi, Yu-Jin; Calabrese, Richard V; Ehrman, Sheryl H; Dickerson, Russell R; Stehr, Jeffrey W

2006-02-01

Emissions inventories significantly affect photochemical air quality model performance and the development of effective control strategies. However, there have been very few studies to evaluate their accuracy. Here, to evaluate a volatile organic compound (VOC) emissions inventory, we implemented a combined approach: comparing the ratios of carbon bond (CB)-IV VOC groups to nitrogen oxides (NOx) or carbon monoxide (CO) using an emission preprocessing model, comparing the ratios of VOC source contributions from a source apportionment technique to NOx or CO, and comparing ratios of CB-IV VOC groups to NOx or CO and the absolute concentrations of CB-IV VOC groups using an air quality model, with the corresponding ratios and concentrations observed at three sites (Maryland, Washington, DC, and New Jersey). The comparisons of the ethene/NOx ratio, the xylene group (XYL)/NOx ratio, and ethene and XYL concentrations between estimates and measurements showed some differences, depending on the comparison approach, at the Maryland and Washington, DC sites. On the other hand, consistent results at the New Jersey site were observed, implying a possible overestimation of vehicle exhaust. However, in the case of the toluene group (TOL), which is emitted mainly from surface coating and printing sources in the solvent utilization category, the ratios of TOL/ NOx or CO, as well as the absolute concentrations revealed an overestimate of these solvent sources by a factor of 1.5 to 3 at all three sites. In addition, the overestimate of these solvent sources agreed with the comparisons of surface coating and printing source contributions relative to NOx from a source apportionment technique to the corresponding value of estimates at the Maryland site. Other studies have also suggested an overestimate of solvent sources, implying a possibility of inaccurate emission factors in estimating VOC emissions from surface coating and printing sources. We tested the impact of these overestimates with a chemical transport model and found little change in ozone but substantial changes in calculated secondary organic aerosol concentrations.

Chemical Characterization and Source Apportionment of Indoor and Outdoor Fine Particulate Matter (PM2.5) in Retirement Communities of the Los Angeles Basin

PubMed Central

Hasheminassab, Sina; Daher, Nancy; Shafer, Martin M.; Schauer, James J.; Delfino, Ralph J.; Sioutas, Constantinos

2014-01-01

Concurrent indoor and outdoor measurements of fine particulate matter (PM2.5) were conducted at three retirement homes in the Los Angeles Basin during two separate phases (cold and warm) between 2005 and 2006. Indoor-to-outdoor relationships of PM2.5 chemical constituents were determined and sources of indoor and outdoor PM2.5 were evaluated using a molecular marker-based chemical mass balance (MM-CMB) model. Indoor levels of elemental carbon (EC) along with metals and trace elements were found to be significantly affected by outdoor sources. EC, in particular, displayed very high indoor-to-outdoor (I/O) mass ratios accompanied by strong I/O correlations, illustrating the significant impact of outdoor sources on indoor levels of EC. Similarly, indoor levels of polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes were strongly correlated with their outdoor components and displayed I/O ratios close to unity. On the other hand, concentrations of n-alkanes and organic acids inside the retirement communities were dominated by indoor sources (e.g. food cooking and consumer products), as indicated by their I/O ratios, which exceeded unity. Source apportionment results revealed that vehicular emissions were the major contributor to both indoor and outdoor PM2.5, accounting for 39 and 46% of total mass, respectively. Moreover, the contribution of vehicular sources to indoor levels was generally comparable to its corresponding outdoor estimate. Other water-insoluble organic matter (other WIOM), which accounts for emissions from uncharacterized primary biogenic sources, displayed a wider range of contributions, varying from 2 to 73% of PM2.5, across all sites and phases of the study. Lastly, higher indoor than outdoor contribution of other water-soluble organic matter (other WSOM) was evident at some of the sites, suggesting the production of secondary aerosols as well as direct emissions from primary sources (including cleaning or other consumer products) at the indoor environments. PMID:24880542

Concentrations and source apportionment of PM10 and associated elemental and ionic species in a lignite-burning power generation area of southern Greece.

PubMed

Argyropoulos, G; Grigoratos, Th; Voutsinas, M; Samara, C

2013-10-01

Ambient concentrations of PM10 and associated elemental and ionic species were measured over the cold and the warm months of 2010 at an urban and two rural sites located in the lignite-fired power generation area of Megalopolis in Peloponnese, southern Greece. The PM10 concentrations at the urban site (44.2 ± 33.6 μg m(-3)) were significantly higher than those at the rural sites (23.7 ± 20.4 and 22.7 ± 26.9 μg m(-3)). Source apportionment of PM10 and associated components was accomplished by an advanced computational procedure, the robotic chemical mass balance model (RCMB), using chemical profiles for a variety of local fugitive dust sources (power plant fly ash, flue gas desulfurization wet ash, feeding lignite, infertile material from the opencast mines, paved and unpaved road dusts, soil), which were resuspended and sampled through a PM10 inlet onto filters and then chemically analyzed, as well as of other common sources such as vehicular traffic, residential oil combustion, biomass burning, uncontrolled waste burning, marine aerosol, and secondary aerosol formation. Geological dusts (road/soil dust) were found to be major PM10 contributors in both the cold and warm periods of the year, with average annual contribution of 32.6 % at the urban site vs. 22.0 and 29.0 % at the rural sites. Secondary aerosol also appeared to be a significant source, contributing 22.1 % at the urban site in comparison to 30.6 and 28.7 % at the rural sites. At all sites, the contribution of biomass burning was most significant in winter (28.2 % at the urban site vs. 14.6 and 24.6 % at the rural sites), whereas vehicular exhaust contribution appeared to be important mostly in the summer (21.9 % at the urban site vs. 11.5 and 10.5 % at the rural sites). The highest contribution of fly ash (33.2 %) was found at the rural site located to the north of the power plants during wintertime, when winds are favorable. In the warm period, the highest contribution of fly ash was found at the rural site located to the south of the power plants, although it was less important (7.2 %). Moderate contributions of fly ash were found at the urban site (5.4 and 2.7 % in the cold and the warm period, respectively). Finally, the mine field was identified as a minor PM10 source, occasionally contributing with lignite dust and/or deposited wet ash dust under dry summer conditions, with the summertime contributions ranging between 3.1 and 11.0 % among the three sites. The non-parametric bootstrapped potential source contribution function analysis was further applied to localize the regions of sources apportioned by the RCMB. For the majority of sources, source regions appeared as being located within short distances from the sampling sites (within the Peloponnesse Peninsula). More distant Greek areas of the NNE sector also appeared to be source regions for traffic emissions and secondary calcium sulfate dust.

Characterization of water-soluble organic aerosol in coastal New England: Implications of variations in size distribution

NASA Astrophysics Data System (ADS)

Ziemba, L. D.; Griffin, R. J.; Whitlow, S.; Talbot, R. W.

2011-12-01

Size distributions up to 10-micron aerosol diameter ( DP) of organic carbon (OC) and water-soluble organic carbon (WSOC) were measured at two sites in coastal New England, slightly inland at Thompson Farm (TF) and offshore at Isles of Shoals (IOS). Significant OC concentrations were measured across the full size distribution at TF and IOS, respectively. The WSOC fraction (WSOC/OC) was largest in the accumulation mode with values of 0.86 and 0.93 and smallest in the coarse mode with values of 0.61 and 0.79 at TF and IOS, respectively. Dicarboxylic acids containing up to five carbon atoms (C 5) were concentrated in droplet and accumulation mode aerosol with only minor contributions in the coarse mode. C 1-C 3 monocarboxylic acids were generally near or below detection limits. Results from proton nuclear magnetic resonance (H +-NMR) spectroscopy analyses showed that the organic functional group characterized by protons in the alpha position to an unsaturated carbon atoms ([H-C-C dbnd ]) was the dominant WSOC functionality at both TF and IOS, constituting 34 and 43% of carbon-weighted H +-NMR signal, respectively. Size distributions of each H +-NMR-resolved organic functionality are presented. Source apportionment using H +-NMR fingerprints is also presented, and results indicate that nearly all of the WSOC at TF and IOS spectroscopically resembled secondary organic aerosol, regardless of DP.

Relative Impact of Emissions Controls and Meteorology on Air Pollution Mitigation Associated with the Asia-Pacific Economic Cooperation (APEC) Conference in Beijing, China

NASA Astrophysics Data System (ADS)

Zhang, Y.; Wang, Y.; Schauer, J. J.; de Foy, B.

2016-12-01

The Beijing government and its surrounding provinces implemented a series of measures to ensure haze-free skies during the 22nd Asia-Pacific Economic Cooperation (APEC) conference (November 10th - 11th, 2014). These measures included restrictions on traffic, construction, and industrial activity. Twelve hour measurements of the concentration and composition of ambient fine particulate matter (PM2.5) were performed for 5 consecutive months near the APEC conference site before (September 11th - November 2nd, 2014), during (November 3rd - 12th, 2014) and after (November 13th, 2014 - January 31st, 2015). The measurements are used in a positive matrix factorization model to determine the contributions from seven sources of PM2.5: secondary aerosols, mobile source, industrial emission, road dust, soil dust, biomass burning and residual oil combustion. The source apportionment results are integrated with backward trajectory analysis using Weather Research and Forecast (WRF) meteorological simulations, which determine the relative influence of new regulation and meteorology upon improved air quality during the APEC conference. Data show that controls are very effective, but meteorology must be taken into account to determine the actual influence of the controls on pollution reduction. The Industry source control is the most effective for reducing concentrations, follows by secondary aerosol and biomass controls, while the least effective control is for the residual oil combustion source. The largest reductions in concentrations occur when air mass transport is from the west-northwest (Ulanqab). Secondary aerosol and mobile source reductions are most significant for air mass transport from the north-northwest (Xilingele League) origin, and least significant for northeast transport (Chifeng via Tangshan conditions). The largest reductions of soil dust, biomass burning, and industrial source are distinctly seen for Ulanqab conditions and least distinct for Xilingele League.

Atmospheric water-soluble organic nitrogen (WSON) in the eastern Mediterranean: origin and ramifications regarding marine productivity

NASA Astrophysics Data System (ADS)

Nehir, Münevver; Koçak, Mustafa

2018-03-01

Aerosol and rain sampling in two size fractions was carried out at a rural site located on the coast of the eastern Mediterranean, Erdemli, Turkey (36°33'54'' N, 34°15'18'' E). A total of 674 aerosol samples in two size fractions (337 coarse, 337 fine) and 23 rain samples were collected between March 2014 and April 2015. Samples were analyzed for NO3-, NH4+ and ancillary water-soluble ions using ion chromatography and water-soluble total nitrogen (WSTN) by applying a high-temperature combustion method. The mean aerosol water-soluble organic nitrogen (WSON) was 23.8 ± 16.3 nmol N m-3, reaching a maximum of 79 nmol N m-3, with about 66 % being associated with coarse particles. The volume weighted mean (VWM) concentration of WSON in rain was 21.5 µmol N L-1. The WSON contributed 37 and 29 % to the WSTN in aerosol and rainwater, respectively. Aerosol WSON concentrations exhibited large temporal variation, mainly due to meteorology and the origin of air mass flow. The highest mean aerosol WSON concentration was observed in the summer and was attributed to the absence of rain and resuspension of cultivated soil in the region. The mean concentration of WSON during dust events (38.2 ± 17.5 nmol N m-3) was 1.3 times higher than that of non-dust events (29.4 ± 13.9 nmol N m-3). Source apportionment analysis demonstrated that WSON was originated from agricultural activities (43 %), secondary aerosol (20 %), nitrate (22 %), crustal material (10 %) and sea salt (5 %). The dry and wet depositions of WSON were equivalent and amounted to 36 % of the total atmospheric WSTN flux.

Formation of Oxidized Organic Aerosol (OOA) through Fog Processing in the Po Valley

NASA Astrophysics Data System (ADS)

Gilardoni, S.; Paglione, M.; Rinaldi, M.; Giulianelli, L.; Massoli, P.; Hillamo, R. E.; Carbone, S.; Lanconelli, C.; Laaksonen, A. J.; Russell, L. M.; Poluzzi, V.; Fuzzi, S.; Facchini, C.

2014-12-01

Aqueous phase chemistry might be responsible for the formation of a significant fraction of the organic aerosol (OA) observed in the atmosphere, and could explain some of the discrepancies between OA concentration and properties predicted by models and observed in the environment. Aerosol - fog interaction and its effect on submicron aerosol properties were investigated in the Po Valley (northern Italy) during fall 2011, in the framework of the Supersite project (ARPA Emilia Romagna). Composition and physical properties of submicron aerosol were measured online by a High Resolution- Time of Flight - Aerosol Mass Spectrometer (HR-TOF-AMS), a Soot Photometer - Aerosol Mass Spectrometer (SP-AMS), and a Tandem Differential Mobility Particle Sizer (TDMPS). Organic functional group analysis was performed off-line by Hydrogen - Nuclear Magnetic Resonance (H-NMR) spectrometry and by Fourier Transform Infrared (FTIR) spectrometry. Aerosol absorption, scattering, and total extinction were measured simultaneously with a Particle Soot Absorption Photometer (PSAP), a Nephelometer, and a Cavity Attenuated Phase Shift Spectrometer particle extinction monitor (CAPS PMex), respectively. Water-soluble organic carbon in fog-water was characterized off-line by HR-TOF-AMS. Fourteen distinct fog events were observed. Fog dissipation left behind an aerosol enriched in particles larger than 400 nm, typical of fog and cloud processing, and dominated by secondary species, including ammonium nitrate, ammonium sulfate and oxidized OA (OOA). Source apportionment of OA allowed us to identify OOA as the difference between total OA and primary OA (hydrocarbon like OA and biomass burning OA). The formation of OOA through fog processing is proved by the correlation of OOA concentration with hydroxyl methyl sulfonate signal and by the similarity of OOA spectra with organic mass spectra obtained by re-aerosolization of fog water samples. The oxygen to carbon ratio and the hydrogen to carbon ratio of this OOA fraction was about 0.6 and 1.3, respectively. Organic functional group analysis showed that OOA observed after fog dissipation was characterized by organic-sulfur and organic-nitrogen species.

Chemical composition and characteristics of ambient aerosols and rainwater residues during Indian summer monsoon: Insight from aerosol mass spectrometry

NASA Astrophysics Data System (ADS)

Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida N.

2016-07-01

Real time composition of non-refractory submicron aerosol (NR-PM1) is measured via Aerosol mass spectrometer (AMS) for the first time during Indian summer monsoon at Kanpur, a polluted urban location located at the heart of Indo Gangetic Plain (IGP). Submicron aerosols are found to be dominated by organics followed by nitrate. Source apportionment of organic aerosols (OA) via positive matrix factorization (PMF) revealed several types of secondary/oxidized and primary organic aerosols. On average, OA are completely dominated by oxidized OA with a very little contribution from biomass burning OA. During rain events, PM1 concentration is decreased almost by 60%, but its composition remains nearly the same. Oxidized OA showed slightly more decrease than primary OAs, probably due to their higher hygroscopicity. The presence of organo nitrates (ON) is also detected in ambient aerosols. Apart from real-time sampling, collected fog and rainwater samples were also analyzed via AMS in offline mode and in the ICP-OES (Inductively coupled plasma - Optical emission spectrometry) for elements. The presence of sea salt, organo nitrates and sulfates has been observed. Rainwater residues are also dominated by organics but their O/C ratios are 15-20% lower than the observed values for ambient OA. Alkali metals such as Ca, Na, K are found to be most abundant in the rainwater followed by Zn. Rainwater residues are also found to be much less oxidized than the aerosols present inside the fog water, indicating presence of less oxidized organics. These findings indicate that rain can act as an effective scavenger of different types of pollutants even for submicron particle range. Rainwater residues also contain organo sulfates which indicate that some portion of the dissolved aerosols has undergone aqueous processing, possibly inside the cloud. Highly oxidized and possibly hygroscopic OA during monsoon period compared to other seasons (winter, post monsoon), indicates that they can act more efficiently as cloud condensation nuclei.

Simultaneous factor analysis of organic particle and gas mass spectra: AMS and PTR-MS measurements at an urban site

NASA Astrophysics Data System (ADS)

Slowik, J. G.; Vlasenko, A.; McGuire, M.; Evans, G. J.; Abbatt, J. P. D.

2010-02-01

During the winter component of the SPORT (Seasonal Particle Observations in the Region of Toronto) field campaign, particulate non-refractory chemical composition and concentration of selected volatile organic compounds (VOCs) were measured by an Aerodyne time-of-flight aerosol mass spectrometer (AMS) and a proton transfer reaction-mass spectrometer (PTR-MS), respectively. Sampling was performed in downtown Toronto ~15 m from a major road. The mass spectra from the AMS and PTR-MS were combined into a unified dataset, which was analysed using positive matrix factorization (PMF). The two instruments were given balanced weight in the PMF analysis by the application of a scaling factor to the uncertainties of each instrument. A residual based metric, Δesc, was used to evaluate the instrument relative weight within each solution. The PMF analysis yielded a 6-factor solution that included factors characteristic of regional transport, local traffic emissions, charbroiling and oxidative processing. The unified dataset provides information on emission sources (particle and VOC) and atmospheric processing that cannot be obtained from the datasets of the individual instruments: (1) apportionment of oxygenated VOCs to either direct emission sources or secondary reaction products; (2) improved correlation of oxygenated aerosol factors with photochemical age; and (3) increased detail regarding the composition of oxygenated organic aerosol factors. This analysis represents the first application of PMF to a unified AMS/PTR-MS dataset.

SOURCE APPORTIONMENT OF EXPOSURES TO VOLATILE ORGANIC COMPOUNDS: II. APPLICATION OF RECEPTOR MODELS TO TEAM STUDY DATA. (R826788)

EPA Science Inventory

Four receptor-oriented source apportionment models were applied to personal exposure measurements for toxic volatile organic compounds (VOCs). The measurements are from the total exposure assessment methodology studies conducted from 1980 to 1984 in New Jersey (NJ) and Califor...

IMPROVING PARTICULATE MATTER SOURCE APPORTIONMENT FOR HEALTH STUDIES: A TRAINED RECEPTOR MODELING APPROACH WITH SENSITIVITY, UNCERTAINTY AND SPATIAL ANALYSES

EPA Science Inventory

An approach for conducting PM source apportionment will be developed, tested, and applied that directly addresses limitations in current SA methods, in particular variability, biases, and intensive resource requirements. Uncertainties in SA results and sensitivities to SA inpu...

Defense Coastal/Estuarine Research Program (DCERP) Strategic Plan

DTIC Science & Technology

2007-09-01

atmospheric deposition. The source apportionment of nutrients from atmospheric deposition (especially nitrogen) to estuarine waters derived from direct...migrating wildlife, and nutrient release from soil weathering, atmospheric deposition represents the only source of new nutrients into the... apportionment to properly assess the contributions of off-site and on-site emission sources to regional levels of PM2.5. In preparing this DCERP Strategic

Distributions of Polycyclic Aromatic Hydrocarbons, Aromatic Ketones, Carboxylic Acids, and Trace Metals in Arctic Aerosols: Long-Range Atmospheric Transport, Photochemical Degradation/Production at Polar Sunrise.

PubMed

Singh, Dharmendra Kumar; Kawamura, Kimitaka; Yanase, Ayako; Barrie, Leonard A

2017-08-15

The distributions, correlations, and source apportionment of aromatic acids, aromatic ketones, polycyclic aromatic hydrocarbons (PAHs), and trace metals were studied in Canadian high Arctic aerosols. Nineteen PAHs including minor sulfur-containing heterocyclic PAH (dibenzothiophene) and major 6 carcinogenic PAHs were detected with a high proportion of fluoranthene followed by benzo[k]fluoranthene, pyrene, and chrysene. However, in the sunlit period of spring, their concentrations significantly declined likely due to photochemical decomposition. During the polar sunrise from mid-March to mid-April, benzo[a]pyrene to benzo[e]pyrene ratios significantly dropped, and the ratios diminished further from late April to May onward. These results suggest that PAHs transported over the Arctic are subjected to strong photochemical degradation at polar sunrise. Although aromatic ketones decreased in spring, concentrations of some aromatic acids such as benzoic and phthalic acids increased during the course of polar sunrise, suggesting that aromatic hydrocarbons are oxidized to result in aromatic acids. However, PAHs do not act as the major source for low molecular weight (LMW) diacids such as oxalic acid that are largely formed at polar sunrise in the arctic atmosphere because PAHs are 1 to 2 orders of magnitude less abundant than LMW diacids. Correlations of trace metals with organics, their sources, and the possible role of trace transition metals are explained.

Source apportionment and health risk assessment among specific age groups during haze and non-haze episodes in Kuala Lumpur, Malaysia.

PubMed

Sulong, Nor Azura; Latif, Mohd Talib; Khan, Md Firoz; Amil, Norhaniza; Ashfold, Matthew J; Wahab, Muhammad Ikram Abdul; Chan, Kok Meng; Sahani, Mazrura

2017-12-01

This study aims to determine PM 2.5 concentrations and their composition during haze and non-haze episodes in Kuala Lumpur. In order to investigate the origin of the measured air masses, the Numerical Atmospheric-dispersion Modelling Environment (NAME) and Global Fire Assimilation System (GFAS) were applied. Source apportionment of PM 2.5 was determined using Positive Matrix Factorization (PMF). The carcinogenic and non-carcinogenic health risks were estimated using the United State Environmental Protection Agency (USEPA) method. PM 2.5 samples were collected from the centre of the city using a high-volume air sampler (HVS). The results showed that the mean PM 2.5 concentrations collected during pre-haze, haze and post-haze periods were 24.5±12.0μgm -3 , 72.3±38.0μgm -3 and 14.3±3.58μgm -3 , respectively. The highest concentration of PM 2.5 during haze episode was five times higher than World Health Organisation (WHO) guidelines. Inorganic compositions of PM 2.5 , including trace elements and water soluble ions were determined using inductively coupled plasma-mass spectrometry (ICP-MS) and ion chromatography (IC), respectively. The major trace elements identified were K, Al, Ca, Mg and Fe which accounted for approximately 93%, 91% and 92% of the overall metals' portions recorded during pre-haze, haze and post-haze periods, respectively. For water-soluble ions, secondary inorganic aerosols (SO 4 2- , NO 3 - and NH 4 + ) contributed around 12%, 43% and 16% of the overall PM 2.5 mass during pre-haze, haze and post-haze periods, respectively. During haze periods, the predominant source identified using PMF was secondary inorganic aerosol (SIA) and biomass burning where the NAME simulations indicate the importance of fires in Sumatra, Indonesia. The main source during pre-haze and post-haze were mix SIA and road dust as well as mineral dust, respectively. The highest non-carcinogenic health risk during haze episode was estimated among the infant group (HI=1.06) while the highest carcinogenic health risk was estimated among the adult group (2.27×10 -5 ). Copyright © 2017 Elsevier B.V. All rights reserved.

Fine Particle Sources and Cardiorespiratory Morbidity: An Application of Chemical Mass Balance and Factor Analytical Source-Apportionment Methods

PubMed Central

Sarnat, Jeremy A.; Marmur, Amit; Klein, Mitchel; Kim, Eugene; Russell, Armistead G.; Sarnat, Stefanie E.; Mulholland, James A.; Hopke, Philip K.; Tolbert, Paige E.

2008-01-01

Background Interest in the health effects of particulate matter (PM) has focused on identifying sources of PM, including biomass burning, power plants, and gasoline and diesel emissions that may be associated with adverse health risks. Few epidemiologic studies, however, have included source-apportionment estimates in their examinations of PM health effects. We analyzed a time-series of chemically speciated PM measurements in Atlanta, Georgia, and conducted an epidemiologic analysis using data from three distinct source-apportionment methods. Objective The key objective of this analysis was to compare epidemiologic findings generated using both factor analysis and mass balance source-apportionment methods. Methods We analyzed data collected between November 1998 and December 2002 using positive-matrix factorization (PMF), modified chemical mass balance (CMB-LGO), and a tracer approach. Emergency department (ED) visits for a combined cardiovascular (CVD) and respiratory disease (RD) group were assessed as end points. We estimated the risk ratio (RR) associated with same day PM concentrations using Poisson generalized linear models. Results There were significant, positive associations between same-day PM2.5 (PM with aero-dynamic diameter ≤ 2.5 μm) concentrations attributed to mobile sources (RR range, 1.018–1.025) and biomass combustion, primarily prescribed forest burning and residential wood combustion, (RR range, 1.024–1.033) source categories and CVD-related ED visits. Associations between the source categories and RD visits were not significant for all models except sulfate-rich secondary PM2.5 (RR range, 1.012–1.020). Generally, the epidemiologic results were robust to the selection of source-apportionment method, with strong agreement between the RR estimates from the PMF and CMB-LGO models, as well as with results from models using single-species tracers as surrogates of the source-apportioned PM2.5 values. Conclusions Despite differences among the source-apportionment methods, these findings suggest that modeled source-apportioned data can produce robust estimates of acute health risk. In Atlanta, there were consistent associations across methods between PM2.5 from mobile sources and biomass burning with both cardiovascular and respiratory ED visits, and between sulfate-rich secondary PM2.5 with respiratory visits. PMID:18414627

Constraining Aerosol Optical Models Using Ground-Based, Collocated Particle Size and Mass Measurements in Variable Air Mass Regimes During the 7-SEAS/Dongsha Experiment

NASA Technical Reports Server (NTRS)

Bell, Shaun W.; Hansell, Richard A.; Chow, Judith C.; Tsay, Si-Chee; Wang, Sheng-Hsiang; Ji, Qiang; Li, Can; Watson, John G.; Khlystov, Andrey

2012-01-01

During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulphate, nitrate, and elemental carbon. Our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulphate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Extinctive features at significantly smaller time scales than the one-day sample period of IMPROVE are more difficult to reproduce, as this requires further knowledge concerning the source apportionment of major chemical components in the model. Consistency between the measured and modeled optical parameters serves as an important link for advancing remote sensing and climate research studies in dynamic aerosol-rich environments like Dongsha.

Source apportionment of soil heavy metals using robust absolute principal component scores-robust geographically weighted regression (RAPCS-RGWR) receptor model.

PubMed

Qu, Mingkai; Wang, Yan; Huang, Biao; Zhao, Yongcun

2018-06-01

The traditional source apportionment models, such as absolute principal component scores-multiple linear regression (APCS-MLR), are usually susceptible to outliers, which may be widely present in the regional geochemical dataset. Furthermore, the models are merely built on variable space instead of geographical space and thus cannot effectively capture the local spatial characteristics of each source contributions. To overcome the limitations, a new receptor model, robust absolute principal component scores-robust geographically weighted regression (RAPCS-RGWR), was proposed based on the traditional APCS-MLR model. Then, the new method was applied to the source apportionment of soil metal elements in a region of Wuhan City, China as a case study. Evaluations revealed that: (i) RAPCS-RGWR model had better performance than APCS-MLR model in the identification of the major sources of soil metal elements, and (ii) source contributions estimated by RAPCS-RGWR model were more close to the true soil metal concentrations than that estimated by APCS-MLR model. It is shown that the proposed RAPCS-RGWR model is a more effective source apportionment method than APCS-MLR (i.e., non-robust and global model) in dealing with the regional geochemical dataset. Copyright © 2018 Elsevier B.V. All rights reserved.

Semi-continuous mass closure of the major components of fine particulate matter in Riverside, CA

NASA Astrophysics Data System (ADS)

Grover, Brett D.; Eatough, Norman L.; Woolwine, Woods R.; Cannon, Justin P.; Eatough, Delbert J.; Long, Russell W.

The application of newly developed semi-continuous aerosol monitors allows for the measurement of all the major species of PM 2.5 on a 1-h time basis. Temporal resolution of both non-volatile and semi-volatile species is possible. A suite of instruments to measure the major chemical species of PM 2.5 allows for semi-continuous mass closure. A newly developed dual-oven Sunset carbon monitor is used to measure non-volatile organic carbon, semi-volatile organic carbon and elemental carbon. Inorganic species, including sulfate and nitrate, can be measured with an ion chromatograph based sampler. Comparison of the sum of the major chemical species in an urban aerosol with mass measured by an FDMS resulted in excellent agreement. Linear regression analysis resulted in a zero-intercept slope of 0.98±0.01 with an R2=0.86. One-hour temporal resolution of the major species of PM 2.5 may reduce the uncertainty in receptor based source apportionment modeling, will allow for better forecasting of PM 2.5 episodes, and may lead to increased understanding of related health effects.

Stable sulfur isotope ratios and chemical compositions of fine aerosols (PM2.5) in Beijing, China.

PubMed

Wei, Lianfang; Yue, Siyao; Zhao, Wanyu; Yang, Wenyi; Zhang, Yingjie; Ren, Lujie; Han, Xiaokun; Guo, Qingjun; Sun, Yele; Wang, Zifa; Fu, Pingqing

2018-08-15

Pervasive particulate pollution has been observed over large areas of the North China Plain. The high level of sulfate, a major component in fine particles, is pronounced during heavy pollution periods. Being different from source apportionments by atmospheric chemistry-transport model and receptor modeling methods, here we utilize sulfur isotopes to discern the potential emission sources. Sixty-five daily PM 2.5 samples were collected at an urban site in Beijing between September 2013 and July 2014. Inorganic ions, organic/elemental carbon and stable sulfur isotopes of sulfate were analyzed. The "fingerprint" characteristics of stable sulfur isotopic composition, together with trajectory clustering modeled by HYSPLIT-4 (HYbrid Single-Particle Lagrangian Integrated Trajectory) and FLEXPART ("FLEXible PARTicle dispersion model"), was employed to identify potential aerosol sources in Beijing. Results exhibited a distinctive seasonality with sulfate, nitrate, ammonium, organic matter, and element carbon being the dominant species of PM 2.5 . Elevated concentrations of chloride with high organic matter were found in autumn and winter as a result of enhanced fossil fuel (mainly coal) combustion. The δ 34 S values of the Beijing aerosols ranged from 2.8‰ to 9.9‰ with an average of 6.0 ± 1.8‰, further indicating that the major sulfur source was direct coal burning emission. Owing to the changing patterns between oxidation pathways of S(IV) in different seasons, δ 34 S values varied with a winter maximum (8.2 ± 1.1‰) and a summer minimum (4.9 ± 1.9‰). The results of trajectory clustering and FLEXPART demonstrated that higher concentrations of sulfate with lower sulfur isotope ratios (4.6 ± 0.8‰) were associated with air masses from the south or east, whereas lower sulfate concentrations with heavier sulfur isotope ratios (6.7 ± 1.6‰) were observed when the air masses were mainly from the north or northwest. These results suggested that the fine aerosol pollution in Beijing, especially sulfate pollution, was mainly due to coal combustion sources from regional and local regions. Copyright © 2018 Elsevier B.V. All rights reserved.

Control of Toxic Chemicals in Puget Sound, Phase 3: Study Of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound

DTIC Science & Technology

2007-01-01

deposition directly to Puget Sound was an important source of PAHs, polybrominated diphenyl ethers (PBDEs), and heavy metals . In most cases, atmospheric...versus Atmospheric Fluxes ........................................................................66  PAH Source Apportionment ...temperature inversions) on air quality during the wet season. A semi-quantitative apportionment study permitted a first-order characterization of source

Biogenic and biomass burning organic aerosol in a boreal forest at Hyytiälä, Finland, during HUMPPA-COPEC 2010

NASA Astrophysics Data System (ADS)

Corrigan, A. L.; Russell, L. M.; Takahama, S.; Äijälä, M.; Ehn, M.; Junninen, H.; Rinne, J.; Petäjä, T.; Kulmala, M.; Vogel, A. L.; Hoffmann, T.; Ebben, C. J.; Geiger, F. M.; Chhabra, P.; Seinfeld, J. H.; Worsnop, D. R.; Song, W.; Auld, J.; Williams, J.

2013-12-01

Submicron aerosol particles were collected during July and August 2010 in Hyytiälä, Finland, to determine the composition and sources of aerosol at that boreal forest site. Submicron particles were collected on Teflon filters and analyzed by Fourier transform infrared (FTIR) spectroscopy for organic functional groups (OFGs). Positive matrix factorization (PMF) was applied to aerosol mass spectrometry (AMS) measurements and FTIR spectra to identify summertime sources of submicron aerosol mass at the sampling site. The two largest sources of organic mass (OM) in particles identified at Hyytiälä were (1) biogenic aerosol from surrounding local forest and (2) biomass burning aerosol, transported 4-5 days from large wildfires burning near Moscow, Russia, and northern Ukraine. The robustness of this apportionment is supported by the agreement of two independent analytical methods for organic measurements with three statistical techniques. FTIR factor analysis was more sensitive to the chemical differences between biogenic and biomass burning organic components, while AMS factor analysis had a higher time resolution that more clearly linked the temporal behavior of separate OM factors to that of different source tracers even though their fragment mass spectrum were similar. The greater chemical sensitivity of the FTIR is attributed to the nondestructive preparation and the functional group specificity of spectroscopy. The FTIR spectra show strong similarities among biogenic and biomass burning factors from different regions as well as with reference OM (namely olive tree burning organic aerosol and α-pinene chamber secondary organic aerosol (SOA)). The biogenic factor correlated strongly with temperature and oxidation products of biogenic volatile organic compounds (BVOCs), included more than half of the oxygenated OFGs (carbonyl groups at 29% and carboxylic acid groups at 22%), and represented 35% of the submicron OM. Compared to previous studies at Hyytiälä, the summertime biogenic OM is 1.5 to 3 times larger than springtime biogenic OM (0.64 μg m-3 and 0.4 μg m-3, measured in 2005 and 2007, respectively), even though it contributed only 35% of OM. The biomass burning factor contributed 25% of OM on average and up to 62% of OM during three periods of transported biomass burning emissions: 26-28 July, 29-30 July, and 8-9 August, with OFG consisting mostly of carbonyl (41%) and alcohol (25%) groups. The high summertime terrestrial biogenic OM (1.7 μg m-3) and the high biomass burning contributions (1.2 μg m-3) were likely due to the abnormally high temperatures that resulted in both stressed boreal forest conditions with high regional BVOC emissions and numerous wildfires in upwind regions.

Measurement of nonvolatile particle number size distribution

NASA Astrophysics Data System (ADS)

Gkatzelis, G. I.; Papanastasiou, D. K.; Florou, K.; Kaltsonoudis, C.; Louvaris, E.; Pandis, S. N.

2016-01-01

An experimental methodology was developed to measure the nonvolatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a nonvolatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol (OA; 40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50-60 % of the particles had a nonvolatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon with an 80 % contribution, while OA was responsible for another 15-20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

Measurement of non-volatile particle number size distribution

NASA Astrophysics Data System (ADS)

Gkatzelis, G. I.; Papanastasiou, D. K.; Florou, K.; Kaltsonoudis, C.; Louvaris, E.; Pandis, S. N.

2015-06-01

An experimental methodology was developed to measure the non-volatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a non-volatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol, OA (40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50-60 % of the particles had a non-volatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon (BC) with an 80 % contribution, while OA was responsible for another 15-20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

A review of current knowledge concerning PM2. 5 chemical composition, aerosol optical properties and their relationships across China

NASA Astrophysics Data System (ADS)

Tao, Jun; Zhang, Leiming; Cao, Junji; Zhang, Renjian

2017-08-01

To obtain a thorough knowledge of PM2. 5 chemical composition and its impact on aerosol optical properties across China, existing field studies conducted after the year 2000 are reviewed and summarized in terms of geographical, interannual and seasonal distributions. Annual PM2. 5 was up to 6 times the National Ambient Air Quality Standards (NAAQS) in some megacities in northern China. Annual PM2. 5 was higher in northern than southern cities, and higher in inland than coastal cities. In a few cities with data longer than a decade, PM2. 5 showed a slight decrease only in the second half of the past decade, while carbonaceous aerosols decreased, sulfate (SO42-) and ammonium (NH4+) remained at high levels, and nitrate (NO3-) increased. The highest seasonal averages of PM2. 5 and its major chemical components were typically observed in the cold seasons. Annual average contributions of secondary inorganic aerosols to PM2. 5 ranged from 25 to 48 %, and those of carbonaceous aerosols ranged from 23 to 47 %, both with higher contributions in southern regions due to the frequent dust events in northern China. Source apportionment analysis identified secondary inorganic aerosols, coal combustion and traffic emission as the top three source factors contributing to PM2. 5 mass in most Chinese cities, and the sum of these three source factors explained 44 to 82 % of PM2. 5 mass on annual average across China. Biomass emission in most cities, industrial emission in industrial cities, dust emission in northern cities and ship emission in coastal cities are other major source factors, each of which contributed 7-27 % to PM2. 5 mass in applicable cities. The geographical pattern of scattering coefficient (bsp) was similar to that of PM2. 5, and that of aerosol absorption coefficient (bap) was determined by elemental carbon (EC) mass concentration and its coating. bsp in ambient condition of relative humidity (RH) = 80 % can be amplified by about 1.8 times that under dry conditions. Secondary inorganic aerosols accounted for about 60 % of aerosol extinction coefficient (bext) at RH greater than 70 %. The mass scattering efficiency (MSE) of PM2. 5 ranged from 3.0 to 5.0 m2 g-1 for aerosols produced from anthropogenic emissions and from 0.7 to 1.0 m2 g-1 for natural dust aerosols. The mass absorption efficiency (MAE) of EC ranged from 6.5 to 12.4 m2 g-1 in urban environments, but the MAE of water-soluble organic carbon was only 0.05 to 0.11 m2 g-1. Historical emission control policies in China and their effectiveness were discussed based on available chemically resolved PM2. 5 data, which provides the much needed knowledge for guiding future studies and emissions policies.

Composition and sources of carbonaceous aerosols in Northern Europe during winter

NASA Astrophysics Data System (ADS)

Glasius, M.; Hansen, A. M. K.; Claeys, M.; Henzing, J. S.; Jedynska, A. D.; Kasper-Giebl, A.; Kistler, M.; Kristensen, K.; Martinsson, J.; Maenhaut, W.; Nøjgaard, J. K.; Spindler, G.; Stenström, K. E.; Swietlicki, E.; Szidat, S.; Simpson, D.; Yttri, K. E.

2018-01-01

Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The Netherlands; Melpitz, Germany) during winter 2013. Analysis of 14C and a set of molecular tracers were used to constrain the sources of EC and OC. During the four-week campaign, most sites (in particular those in Germany and The Netherlands) were affected by an episode during the first two weeks with high concentrations of aerosol, as continental air masses were transported westward. The analysis results showed a clear, increasing north to south gradient for most molecular tracers. Total carbon (TC = OC + EC) at Birkenes showed an average concentration of 0.5 ± 0.3 μg C m-3, whereas the average concentration at Melpitz was 6.0 ± 4.3 μg C m-3. One weekly mean TC concentration as high as 11 μg C m-3 was observed at Melpitz. Average levoglucosan concentrations varied by an order of magnitude from 25 ± 13 ng m-3 (Birkenes) to 249 ± 13 ng m-3 (Melpitz), while concentrations of tracers of fungal spores (arabitol and mannitol) and vegetative debris (cellulose) were very low, showing a minor influence of primary biological aerosol particles during the North European winter. The fraction of modern carbon generally varied from 0.57 (Melpitz) to 0.91 (Birkenes), showing an opposite trend compared to the molecular tracers and TC. Total concentrations of 10 biogenic and anthropogenic carboxylic acids, mainly of secondary origin, were 4-53 ng m-3, with the lowest concentrations observed at Birkenes and the highest at Melpitz. However, the highest relative concentrations of carboxylic acids (normalized to TC) were observed at the most northern sites. Levels of organosulphates and nitrooxy organosulphates varied more than two orders of magnitude, from 2 to 414 ng m-3, between individual sites and samples. The three sites Melpitz, Rotterdam and Cabauw, located closest to source regions in continental Europe, showed very high levels of organosulphates and nitrooxy organosulphates (up to 414 ng m-3) during the first two weeks of the study, while low levels (<7 ng m-3) were found at all sites except Melpitz during the last week. The large variation in organosulphate levels probably reflects differences in the presence of acidic sulphate aerosols, known from laboratory studies to accelerate the formation of these compounds. On average, the ratio of organic sulphate to inorganic sulphate was 1.5 ± 1.0% (range 0.1-3.4%). Latin-hypercube source apportionment techniques identified biomass burning as the major source of OC for all samples at all sites (typically >40% of TC), while use and combustion of fossil fuels was the second most important source. Furthermore, EC from biomass burning accounted for 7-16% of TC, whereas EC from fossil sources contributed to <2-23% of TC, of which the highest percentages were observed for low-concentration aerosol samples. Unresolved non-fossil sources (such as cooking and biogenic secondary organic aerosols) did not account for more than 5-12% of TC. The results confirm that wood combustion is a major source to OC and EC in Northern Europe during winter.

Chemical and optical properties of PM2.5 from on-road operation of light duty vehicles in Delhi city.

PubMed

Jaiprakash; Habib, Gazala

2017-05-15

This study reports emission factors of PM 2.5 , elemental carbon (EC), organic carbon (OC), ions, trace elements and mass absorption cross-sections (MAC) of aerosol emitted from the on-road operation of light duty vehicles of different vintages. A portable dilution system was used to achieve complete quenching of aerosol at near ambient condition. The particles were collected on the filters and analyzed for chemical and light absorbing properties of aerosol. The diesel-powered passenger cars emitted higher PM 2.5 (56-356mgkm -1 ) with a large fraction of EC (37-65%), while emissions from gasoline (46-78mgkm -1 ), and CNG vehicles (33-34mgkm -1 ) were low and contained low EC (5-15%) and remarkably high OC (46-91%). The MAC of aerosols for diesel vehicles (32-208m 2 g -1 of PM 2.5 ) were well explained by EC content (31-62%) and showed similarity with MAC values reported for wood fuel combustion in cooking stoves indicating the two sources cannot be resolved on the basis of light absorption properties in source apportionment studies. Ionic contributions to PM 2.5 were highest for 4W-gasoline (11-19%) compared to 4W-diesel (7-11%), and CNG (9-10%). The abundance of ions such as Na + , Ca 2+ , SO 4 2- , NO 3 - , and NH 4 + could be due to use of lubricant oil and abrasive nature of engine of old vehicles. Trace elements (Al, Fe, Zn, Pb, and Cu) emitted from after-treatment devices, additives in lube oil, and wearing of engine components, were found to be 2-14%, 3-8% and 11-12% of total PM 2.5 for 4W of diesel, gasoline, and CNG respectively. This study indicates that aerosol emissions from on-road vehicles show a strong dependency on vehicle maintenance, engine type and after-treatment techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

Source apportionment of exposures to volatile organic compounds. I. Evaluation of receptor models using simulated exposure data

NASA Astrophysics Data System (ADS)

Miller, Shelly L.; Anderson, Melissa J.; Daly, Eileen P.; Milford, Jana B.

Four receptor-oriented source apportionment models were evaluated by applying them to simulated personal exposure data for select volatile organic compounds (VOCs) that were generated by Monte Carlo sampling from known source contributions and profiles. The exposure sources modeled are environmental tobacco smoke, paint emissions, cleaning and/or pesticide products, gasoline vapors, automobile exhaust, and wastewater treatment plant emissions. The receptor models analyzed are chemical mass balance, principal component analysis/absolute principal component scores, positive matrix factorization (PMF), and graphical ratio analysis for composition estimates/source apportionment by factors with explicit restriction, incorporated in the UNMIX model. All models identified only the major contributors to total exposure concentrations. PMF extracted factor profiles that most closely represented the major sources used to generate the simulated data. None of the models were able to distinguish between sources with similar chemical profiles. Sources that contributed <5% to the average total VOC exposure were not identified.

Problems in the fingerprints based polycyclic aromatic hydrocarbons source apportionment analysis and a practical solution.

PubMed

Zou, Yonghong; Wang, Lixia; Christensen, Erik R

2015-10-01

This work intended to explain the challenges of the fingerprints based source apportionment method for polycyclic aromatic hydrocarbons (PAH) in the aquatic environment, and to illustrate a practical and robust solution. The PAH data detected in the sediment cores from the Illinois River provide the basis of this study. Principal component analysis (PCA) separates PAH compounds into two groups reflecting their possible airborne transport patterns; but it is not able to suggest specific sources. Not all positive matrix factorization (PMF) determined sources are distinguishable due to the variability of source fingerprints. However, they constitute useful suggestions for inputs for a Bayesian chemical mass balance (CMB) analysis. The Bayesian CMB analysis takes into account the measurement errors as well as the variations of source fingerprints, and provides a credible source apportionment. Major PAH sources for Illinois River sediments are traffic (35%), coke oven (24%), coal combustion (18%), and wood combustion (14%). Copyright © 2015. Published by Elsevier Ltd.

Identification and chemical characterization of industrial particulate matter sources in southwest Spain.

PubMed

Alastuey, Andrés; Querol, Xavier; Plana, Feliciano; Viana, Mar; Ruiz, Carmen R; Sánchez de la Campa, Ana; de la Rosa, Jesús; Mantilla, Enrique; García dos Santos, Saul

2006-07-01

A detailed physical and chemical characterization of coarse particulate matter (PM10) and fine particulate matter (PM2.5) in the city of Huelva (in Southwestern Spain) was carried out during 2001 and 2002. To identify the major emission sources with a significant influence on PM10 and PM2.5, a methodology was developed based on the combination of: (1) real-time measurements of levels of PM10, PM2.5, and very fine particulate matter (PM1); (2) chemical characterization and source apportionment analysis of PM10 and PM2.5; and (3) intensive measurements in field campaigns to characterize the emission plumes of several point sources. Annual means of 37, 19, and 16 microg/m3 were obtained for the study period for PM10, PM2.5, and PM1, respectively. High PM episodes, characterized by a very fine grain size distribution, are frequently detected in Huelva mainly in the winter as the result of the impact of the industrial emission plumes on the city. Chemical analysis showed that PM at Huelva is characterized by high PO4(3-) and As levels, as expected from the industrial activities. Source apportionment analyses identified a crustal source (36% of PM10 and 31% of PM2.5); a traffic-related source (33% of PM10 and 29% of PM2.5), and a marine aerosol contribution (only in PM10, 4%). In addition, two industrial emission sources were identified in PM10 and PM2.5: (1) a petrochemical source, 13% in PM10 and 8% in PM2.5; and (2) a mixed metallurgical-phosphate source, which accounts for 11-12% of PM10 and PM2.5. In PM2.5 a secondary source has been also identified, which contributed to 17% of the mass. A complete characterization of industrial emission plumes during their impact on the ground allowed for the identification of tracer species for specific point sources, such as petrochemical, metallurgic, and fertilizer and phosphate production industries.

Air Quality Monitoring and Forecasting Applications of Suomi NPP VIIRS Aerosol Products

NASA Astrophysics Data System (ADS)

Kondragunta, Shobha

The Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument was launched on October 28, 2011. It provides Aerosol Optical Thickness (AOT) at two different spatial resolutions: a pixel level (~750 m at nadir) product called the Intermediate Product (IP) and an aggregated (~6 km at nadir) product called the Environmental Data Record (EDR), and a Suspended Matter (SM) EDR that provides aerosol type (dust, smoke, sea salt, and volcanic ash) information. An extensive validation of VIIRS best quality aerosol products with ground based L1.5 Aerosol Robotic NETwork (AERONET) data shows that the AOT EDR product has an accuracy/precision of -0.01/0.11 and 0.01/0.08 over land and ocean respectively. Globally, VIIRS mean AOT EDR (0.20) is similar to Aqua MODIS (0.16) with some important regional and seasonal differences. The accuracy of the SM product, however, is found to be very low (20 percent) when compared to Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) and AERONET. Several algorithm updates which include a better approach to retrieve surface reflectance have been developed for AOT retrieval. For dust aerosol type retrieval, a new approach that takes advantage of spectral dependence of Rayleigh scattering, surface reflectance, dust absorption in the deep blue (412 nm), blue (440 nm), and mid-IR (2.2 um) has been developed that detects dust with an accuracy of ~80 percent. For smoke plume identification, a source apportionment algorithm that combines fire hot spots with AOT imagery has been developed that provides smoke plume extent with an accuracy of ~70 percent. The VIIRS aerosol products will provide continuity to the current operational use of aerosol products from Aqua and Terra MODIS. These include aerosol data assimilation in Naval Research Laboratory (NRL) global aerosol model, verification of National Weather Service (NWS) dust and smoke forecasts, exceptional events monitoring by different states, air quality warnings by Environmental Protection Agency (EPA). This talk will provide an overview of VIIRS algorithms, aerosol product validation, and examples of various applications with a discussion on the relevance of product accuracy.

Relative impact of emissions controls and meteorology on air pollution mitigation associated with the Asia-Pacific Economic Cooperation (APEC) conference in Beijing, China.

PubMed

Wang, Yuqin; Zhang, Yang; Schauer, James Jay; de Foy, Benjamin; Guo, Bo; Zhang, Yuanxun

2016-11-15

The Beijing government and its surrounding provinces implemented a series of measures to ensure haze-free skies during the 22(nd) Asia-Pacific Economic Cooperation (APEC) conference (November 10(th)-11(th), 2014). These measures included restrictions on traffic, construction, and industrial activity. Twelve hour measurements of the concentration and composition of ambient fine particulate matter (PM2.5) were performed for 5 consecutive months near the APEC conference site before (September 11(th)-November 2(nd), 2014), during (November 3(rd)-12(th), 2014) and after (November 13(th), 2014-January 31(st), 2015). The measurements are used in a positive matrix factorization model to determine the contributions from seven sources of PM2.5: secondary aerosols, traffic exhaust, industrial emission, road dust, soil dust, biomass burning and residual oil combustion. The source apportionment results are integrated with backward trajectory analysis using Weather Research and Forecast (WRF) meteorological simulations, which determine the relative influence of new regulation and meteorology upon improved air quality during the APEC conference. Data show that controls are very effective, but meteorology must be taken into account to determine the actual influence of the controls on pollution reduction. The industry source control is the most effective for reducing concentrations, followed by secondary aerosol and biomass controls, while the least effective control is for the residual oil combustion source. The largest reductions in concentrations occur when air mass transport is from the west-northwest (Ulanqab). Secondary aerosol and traffic exhaust reductions are most significant for air mass transport from the north-northwest (Xilingele League) origin, and least significant for northeast transport (Chifeng via Tangshan conditions). The largest reductions of soil dust, biomass burning, and industrial source are distinctly seen for Ulanqab conditions and least distinct for Xilingele League. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of the absorption Ångström exponents for traffic and wood burning in the Aethalometer-based source apportionment using radiocarbon measurements of ambient aerosol

NASA Astrophysics Data System (ADS)

Zotter, Peter; Herich, Hanna; Gysel, Martin; El-Haddad, Imad; Zhang, Yanlin; Močnik, Griša; Hüglin, Christoph; Baltensperger, Urs; Szidat, Sönke; Prévôt, André S. H.

2017-03-01

Equivalent black carbon (EBC) measured by a multi-wavelength Aethalometer can be apportioned to traffic and wood burning. The method is based on the differences in the dependence of aerosol absorption on the wavelength of light used to investigate the sample, parameterized by the source-specific absorption Ångström exponent (α). While the spectral dependence (defined as α values) of the traffic-related EBC light absorption is low, wood smoke particles feature enhanced light absorption in the blue and near ultraviolet. Source apportionment results using this methodology are hence strongly dependent on the α values assumed for both types of emissions: traffic αTR, and wood burning αWB. Most studies use a single αTR and αWB pair in the Aethalometer model, derived from previous work. However, an accurate determination of the source specific α values is currently lacking and in some recent publications the applicability of the Aethalometer model was questioned.Here we present an indirect methodology for the determination of αWB and αTR by comparing the source apportionment of EBC using the Aethalometer model with 14C measurements of the EC fraction on 16 to 40 h filter samples from several locations and campaigns across Switzerland during 2005-2012, mainly in winter. The data obtained at eight stations with different source characteristics also enabled the evaluation of the performance and the uncertainties of the Aethalometer model in different environments. The best combination of αTR and αWB (0.9 and 1.68, respectively) was obtained by fitting the Aethalometer model outputs (calculated with the absorption coefficients at 470 and 950 nm) against the fossil fraction of EC (ECF / EC) derived from 14C measurements. Aethalometer and 14C source apportionment results are well correlated (r = 0.81) and the fitting residuals exhibit only a minor positive bias of 1.6 % and an average precision of 9.3 %. This indicates that the Aethalometer model reproduces reasonably well the 14C results for all stations investigated in this study using our best estimate of a single αWB and αTR pair. Combining the EC, 14C, and Aethalometer measurements further allowed assessing the dependence of the mass absorption cross section (MAC) of EBC on its source. Results indicate no significant difference in MAC at 880 nm between EBC originating from traffic or wood-burning emissions. Using ECF / EC as reference and constant a priori selected αTR values, αWB was also calculated for each individual data point. No clear station-to-station or season-to-season differences in αWB were observed, but αTR and αWB values are interdependent. For example, an increase in αTR by 0.1 results in a decrease in αWB by 0.1. The fitting residuals of different αTR and αWB combinations depend on ECF / EC such that a good agreement cannot be obtained over the entire ECF / EC range using other α pairs. Additional combinations of αTR = 0.8, and 1.0 and αWB = 1.8 and 1.6, respectively, are possible but only for ECF / EC between ˜ 40 and 85 %. Applying α values previously used in the literature such as αWB of ˜ 2 or any αWB in combination with αTR = 1.1 to our data set results in large residuals. Therefore we recommend to use the best α combination as obtained here (αTR = 0.9 and αWB = 1.68) in future studies when no or only limited additional information like 14C measurements are available. However, these results were obtained for locations impacted by black carbon (BC) mainly from traffic consisting of a modern car fleet and residential wood combustion with well-constrained combustion efficiencies. For regions of the world with different combustion conditions, additional BC sources, or fuels used, further investigations are needed.

SOURCE APPORTIONMENT OF PM 2.5 AND CARBON IN SEATTLE USING CHEMICAL MASS BALANCE AND POSITIVE MATRIX FACTORIZATION

EPA Science Inventory

Three years of PM2.5 speciated data were collected and chemically analyzed using the IMPROVE protocol at the Beacon Hill site in Seattle. The data were analyzed by the Chemical Mass Balance Version 8 (CMB8) and Positive Matrix Factorization (PMF) source apportionment models. T...

Stable carbon isotopes and levoglucosan for PM2.5 elemental carbon source apportionments in the largest city of Northwest China

NASA Astrophysics Data System (ADS)

Zhao, Zhuzi; Cao, Junji; Zhang, Ting; Shen, Zhenxing; Ni, Haiyan; Tian, Jie; Wang, Qiyuan; Liu, Suixin; Zhou, Jiamao; Gu, Jian; Shen, Ganzhou

2018-07-01

Stable carbon isotopes provide information on aerosol sources, but no extensive long-term studies of these isotopes have been conducted in China, and they have mainly been used for qualitative rather than quantitative purposes. Here, 24 h PM2.5 samples (n = 58) were collected from July 2008 to June 2009 at Xi'an, China. The concentrations of organic and elemental carbon (OC and EC), water-soluble OC, and the stable carbon isotope abundances of OC and EC were determined. In spring, summer, autumn and winter, the mean stable carbon isotope in OC (δ13COC) were -26.4 ± 0.6, -25.8 ± 0.7, -25.0 ± 0.6 and -24.4 ± 0.8‰, respectively, and the corresponding δ13CEC values were -25.5 ± 0.4, -25.5 ± 0.8, -25.2 ± 0.7 and -23.7 ± 0.6‰. Large δ13CEC and δ13COC values in winter can be linked to the burning coal for residential heating. Less biomass is burned during spring and summer than winter or fall (manifested in the levels of levoglucosan, i.e., 178, 85, 370, 935 ng m-3 in spring, summer, autumn, and winter), and the more negative δ13COC in the warmer months can be explained by the formation of secondary organic aerosols. A levoglucosan tracer method combined with an isotope mass balance analysis indicated that biomass burning accounted for 1.6-29.0% of the EC, and the mean value in winter (14.9 ± 7.5%) was 7 times higher than summer (2.1 ± 0.4%), with intermediate values of 6.1 ± 5.6 and 4.5 ± 2.4% in autumn and spring. Coal combustion accounted for 45.9 ± 23.1% of the EC overall, and the percentages were 63.0, 37.2, 36.7, and 33.7% in winter, autumn, summer and spring respectively. Motor vehicles accounted for 46.6 ± 26.5% of the annual EC, and these contributed over half (56.7-61.8%) of the EC in all seasons except winter. Correlations between motor vehicle-EC and coal combustion-EC with established source indicators (B(ghi)P and As) support the source apportionment results. This paper describes a simple and accurate method for apportioning the sources of EC, and the results may be beneficial for developing model simulations as well as controlling strategies in future.

Biogenic and biomass burning organic aerosol in a boreal forest at Hyytiälä, Finland, during HUMPPA-COPEC 2010

NASA Astrophysics Data System (ADS)

Corrigan, A. L.; Russell, L. M.; Takahama, S.; Äijälä, M.; Ehn, M.; Junninen, H.; Rinne, J.; Petäjä, T.; Kulmala, M.; Vogel, A. L.; Hoffmann, T.; Ebben, C. J.; Geiger, F. M.; Chhabra, P.; Seinfeld, J. H.; Worsnop, D. R.; Song, W.; Auld, J.; Williams, J.

2013-06-01

Submicron aerosol particles were collected during July and August 2010 in Hyytiälä, Finland, to determine the composition and sources of aerosol at that Boreal forest site. Submicron particles were collected on Teflon filters and analyzed by Fourier transform infrared (FTIR) spectroscopy for organic functional groups (OFG). Positive matrix factorization (PMF) was applied to aerosol mass spectrometry (AMS) measurements and FTIR spectra to identify summertime sources of submicron aerosol mass at the sampling site. The two largest sources of organic mass (OM) in particles identified at Hyytiälä were (1) biogenic aerosol from surrounding local forest and (2) biomass burning aerosol, transported 4-5 days from large wildfires burning near Moscow, Russia, and northern Ukraine. The robustness of this apportionment is supported by the agreement of two independent analytical methods for organic measurements with three statistical techniques. FTIR factor analysis was more sensitive to the chemical differences between biogenic and biomass burning organic components, while AMS factor analysis had a higher time resolution that more clearly linked the temporal behavior of separate OM factors to that of different source tracers even though their fragment mass spectrum were similar. The greater chemical sensitivity of the FTIR is attributed to the nondestructive preparation and the functional group specificity of spectroscopy. The FTIR spectra show strong similarities among biogenic and biomass burning factors from different regions as well as with reference OM (namely olive tree burning BBOA and α-pinene chamber secondary organic aerosol (SOA)). The biogenic factor correlated strongly with temperature and oxidation products of biogenic volatile organic compounds (BVOCs), included more than half oxygenated OFGs (carbonyl groups at 29% and carboxylic acid groups at 22%), and represented 35% of the submicron OM. Compared to previous studies at Hyytiälä, the summertime biogenic OM is 1.5 to 3 times larger than springtime biogenic OM (0.64 μg m-3 and 0.4 μg m-3, measured in 2005 and 2007, respectively), even though it contributed only 35% of OM. The biomass burning factor contributed 25% OM on average and up to 62% OM during three periods of transported biomass burning emissions: 26-28 July, 29-30 July, and 8-9 August, with OFG consisting mostly of carbonyl (41%) and alcohol (25%) groups. The high summertime terrestrial biogenic OM (1.7 μg m-3) and the high biomass burning contributions (1.2 μg m-3) were likely due to the abnormally high temperatures that resulted in both stressed boreal forest conditions with high regional BVOC emissions and numerous wildfires in upwind regions.

[Size distributions and source apportionment of soluble ions in aerosol in Nanjing].

PubMed

Xue, Guo-Qiang; Zhu, Bin; Wang, Hong-Lei

2014-05-01

To explore the seasonal variation and source apportionment of soluble ions in PM10, PM2.1 and PM1.1, the aerosol mass. concentration and soluble ion concentration were investigated during a one-year observation in the urban-district and north suburb. As the results showed, (1)The concentrations of PM10, PM2.1, PM1.1 were in the order of winter > spring > autumn > summer. In spring, summer and autumn, the concentrations of PM10, PM2.1, PM1.1 in the north suburb were higher than in the urban, while the situation, was opposite in winter. (2) SO(2-)(4), NO(-)(3), Ca2+, NH(+)(4), Cl-, K+, Na+, F-, NO;, Mg2+ were measured, and their total concentration in PM10 was 46 microg.m -3 in urban sites and 39.6 microg m in north suburbs. Mass fraction percentage o f water soluble ion in PM2.1-10, PM1 1-2.1, PM1.1 in the urban district increased from 20.4% to 49.5% and 56% , and the value in the north suburb increased from 18.3% to 37. 9% and 42.5%. (3) Major ions, SO(2-)(4), NO(-)(3) , NH(+)(4) , second components and Ca2+ , had significant seasonal variation. In the urban district, the highest concentrations were observed in winter, and the lowest in summer, while in the. north suburb, the highest concentrations were observed in spring, and the lowest in summer. The seasonal changing climate in Nanjing and different anthropogenic influences with land surface in urban-suburb may be the major factors for the ions' seasonal variation. (4) NH(+)(4) , SO(2-)(4) , NO(-)(3) came from secondary chemical reactions of NH3, SO2, NO,, and these precursors mostly came from automobile exhaust in Summer while equally came from automobile exhaust and fossil fuel in winter. Cl- came from biomass burning in Winter . while transported from sea salt with Na+ in Summer. Ca2+ and Mg2+ came from ground dust and construction dust. K+, F- , NO(-)(2) may come from biomass burning and industrial emissions.

Source apportionment of carbonaceous aerosols in a megacity of northwest China: insights from radiocarbon measurement

NASA Astrophysics Data System (ADS)

Ni, Haiyan; Huang, Rujin; Dusek, Ulrike

2017-04-01

Fine particulate matter (PM2.5) samples were collected from 5 July 2008 to 27 June 2009 at Xi'an, a very polluted megacity in Northwest China. The 24 h averaged PM2.5concentrations (ranged from 32 μg m-3 to 339 μg m-3) were 1-14 times higher than the WHO guideline for 24 h PM2.5(25 μg m-3). In this work, we unambiguously quantify fossil (e.g., vehicle emissions, coal burning etc.) and non-fossil (e.g., biomass burning, cooking, biogenic emissions etc.) contributions to organic carbon (OC) and elemental carbon (EC) of PM2.5using radiocarbon (14C) measurement. In addition, we measured PM2.5 major components and source markers, including OC and EC, ions, trace elements, polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (o-PAHs), anhydrous sugars and hopanes. The preliminary results of radiocarbon measurements in OC and EC show that the annual mean contributions from fossil-fuel combustion to EC was 76 ± 8% (6 ± 2 μg m-3). The remaining 24 ± 8% (2 ± 1 μg m-3) was attributed to biomass burning, with higher contribution in the cold period (˜33%) compared to the warm period (˜21%), due to enhanced emissions from local biomass burning activities in winter. In contrast with EC, OC was dominated by non-fossil sources, with an annual average of 54 ± 8 % (13 ± 10 μg m-3). Clear seasonal variations were seen in OC concentrations both from fossil fuel (OCff), and from non-fossil sources (OCnf), with maxima in the cold period and minima in the warm period, because of enhanced fossil and non-fossil activities in winter, mainly biomass burning and domestic coal burning. Further source apportionment of OC, including primary/secondary fossil OC, primary/secondary non-fossil OC, will be conducted by combining 14C results with positive matrix factorization (PMF) analysis of organic matter (OM).

Radiocarbon determination of fossil and contemporary carbon contribution to aerosol in the Pacific Islands.

PubMed

Isley, C F; Nelson, P F; Taylor, M P; Williams, A A; Jacobsen, G E

2018-06-21

Combustion emissions are of growing concern across all Pacific Island Countries, which account for >10,000 km 2 of the earth's surface area; as for many other small island states globally. Apportioning emissions inputs for Suva, the largest Pacific Island city, will aid in development of emission reduction strategies. Total suspended particulate (TSP) and fine particulate (PM 2.5 ) samples were collected for Suva City, a residential area (Kinoya, TSP) and a mainly ocean-influenced site (Suva Point, TSP) from 2014 to 2015. Percentages of contemporary and fossil carbon were determined by radiocarbon analysis (accelerator mass spectrometry); for non‑carbonate carbon (NCC), elemental carbon (EC) and organic carbon (OC). Source contributions to particulate matter were identified and the accuracy of previous emissions inventory and source apportionment studies was evaluated. Suva Point NCC concentrations (2.7 ± 0.4 μg/m 3 ) were four times lower than for City (13 ± 2 μg/m 3 in TSP) and Kinoya (13 ± 1 μg/m 3 in TSP); demonstrating the contribution of land-based emissions activities in city and residential areas. In Suva City, total NCC in air was 81% (79%-83%) fossil carbon, from vehicles, shipping, power generation and industry; whilst in the residential area, 48% (46%-50%) of total NCC was contemporary carbon; reflecting the higher incidence of biomass and waste burning and of cooking activities. Secondary organic fossil carbon sources contributed >36% of NCC mass at the city and >29% at Kinoya; with biogenic carbon being Kinoya's most significant source (approx. 30% of NCC mass). These results support the previous source apportionment studies for the city area; yet show that, in line with emissions inventory studies, biomass combustion contributes more PM 2.5 mass in residential areas. Hence air quality management strategies need to target open burning activities as well as fossil fuel combustion. Copyright © 2018 Elsevier B.V. All rights reserved.

A Regional Assessment of Marine Vessel PM2.5 Impacts in the U.S. Pacific Northwest Using a Receptor Based Source Apportionment Method

EPA Science Inventory

This work reports the results of a regional receptor-based source apportionment analysis using the Positive Matrix Factorization (PMF) model on chemically speciated PM2.5 data from 36 urban and rural monitoring sites within the U.S. Pacific Northwest. The approach taken is to mo...

Tracking Intercontinental Dust Transport With Radiogenic Isotopes: Hefei, China to California, Spring 2002

NASA Astrophysics Data System (ADS)

Christensen, J. N.; Cliff, S. S.; Vancuren, R. A.; Perry, K. D.; Depaolo, D. J.

2006-12-01

Research over the past decade has highlighted the importance of intercontinental transport and exchange of atmospheric aerosols, including soil-derived dust and industrial pollutants. Far-traveled aerosols can affect air quality, atmospheric radiative forcing and cloud formation and can be an important component in soils. Principal component analysis of elemental data for aerosols collected over California has identified a persistent Asian soil dust component that peaks with Asian dust storm events [1]. Isotopic fingerprinting can provide an additional and potentially more discriminating tool for tracing sources of dust. For example, the naturally variable isotopic compositions of Sr and Nd reflect both the geochemistry of the dust source and its pre- weathering geologic history. Sr and Nd isotopic data and chemical data have been collected for a time series of PM2.5 filter samples from Hefei, China taken from eraly April into early May, 2002. This period encompassed a series of dust storms. The sampling time frame overlapped with the 2002 Intercontinental Transport and Chemical Transformation (ITCT-2K2) experiment along the Pacific coast of North America and inland California. Highs in 87Sr/86Sr in the Hefei time series coincide with peaks in Ca and Si representing peaks in mineral particulate loading resulting from passing dust storms. Mixing diagrams combining isotopic data with chemical data identify several components; a high 87Sr/86Sr component that we identify with mineral dust (loess), and two different low 87Sr/86Sr components (local sources and marine aerosol). Using our measured isotopic composition of the "loess" standard CJ-1 [2] as representative of the pure high 87Sr/86Sr component, we calculate 24 hour average loess particulate concentrations in air which range up to 35 micrograms per cubic meter. Marine aerosol was a major component on at least one of the sampled days. The results for the Hefei samples provide a basis for our isotopic study of California mineral aerosols, including the identification and apportionment of local and far-traveled Asian dust components and their variation in time. [1]VanCuren R.A., Cliff, S.S., Perry, K.D. and Jimenez-Cruz, M. (2005) J. Geophys. Res., 110, D09S90, doi: 10.1029/2004JD004973 [2]Nishikawa, M., Hao, Q. and Morita, M. (2000) Global Environ. Res. 4, 1:103-113.

Weak acid extractable metals in Bramble Bay, Queensland, Australia: temporal behaviour, enrichment and source apportionment.

PubMed

Brady, James P; Ayoko, Godwin A; Martens, Wayde N; Goonetilleke, Ashantha

2015-02-15

Sediment samples were taken from six sampling sites in Bramble Bay, Queensland, Australia between February and November in 2012. They were analysed for a range of heavy metals including Al, Fe, Mn, Ti, Ce, Th, U, V, Cr, Co, Ni, Cu, Zn, As, Cd, Sb, Te, Hg, Tl and Pb. Fraction analysis, Enrichment Factors and Principal Component Analysis-Absolute Principal Component Scores (PCA-APCS) were carried out in order to assess metal pollution, potential bioavailability and source apportionment. Cr and Ni exceeded the Australian Interim Sediment Quality Guidelines at some sampling sites, while Hg was found to be the most enriched metal. Fraction analysis identified increased weak acid soluble Hg and Cd during the sampling period. Source apportionment via PCA-APCS found four sources of metals pollution, namely, marine sediments, shipping, antifouling coatings and a mixed source. These sources need to be considered in any metal pollution control measure within Bramble Bay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Organic aerosols over Indo-Gangetic Plain: Sources, distributions and climatic implications

NASA Astrophysics Data System (ADS)

Singh, Nandita; Mhawish, Alaa; Deboudt, Karine; Singh, R. S.; Banerjee, Tirthankar

2017-05-01

Organic aerosol (OA) constitutes a dominant fraction of airborne particulates over Indo-Gangetic Plain (IGP) especially during post-monsoon and winter. Its exposure has been associated with adverse health effects while there are evidences of its interference with Earth's radiation balance and cloud condensation (CC), resulting possible alteration of hydrological cycle. Therefore, presence and effects of OA directly link it with food security and thereby, sustainability issues. In these contexts, atmospheric chemistry involving formation, volatility and aging of primary OA (POA) and secondary OA (SOA) have been reviewed with specific reference to IGP. Systematic reviews on science of OA sources, evolution and climate perturbations are presented with databases collected from 82 publications available throughout IGP till 2016. Both gaseous and aqueous phase chemical reactions were studied in terms of their potential to form SOA. Efforts were made to recognize the regional variation of OA, its chemical constituents and sources throughout IGP and inferences were made on its possible impacts on regional air quality. Mass fractions of OA to airborne particulate showed spatial variation likewise in Lahore (37 and 44% in fine and coarse fractions, respectively), Patiala (28 and 37%), Delhi (25 and 38%), Kanpur (24 and 30%), Kolkata (11 and 21%) and Dhaka. Source apportionment studies indicate biomass burning, coal combustion and vehicular emissions as predominant OA sources. However, sources represent considerable seasonal variations with dominance of gasoline and diesel emissions during summer and coal and biomass based emissions during winter and post-monsoon. Crop residue burning over upper-IGP was also frequently held responsible for massive OA emission, mostly characterized by its hygroscopic nature, thus having potential to act as CC nuclei. Conclusively, climatic implication of particulate bound OA has been discussed in terms of its interaction with radiation balance.

Comprehensive assessment of PM2.5 physicochemical properties during the Southeast Asia dry season (southwest monsoon)

NASA Astrophysics Data System (ADS)

Khan, Md Firoz; Sulong, Nor Azura; Latif, Mohd Talib; Nadzir, Mohd Shahrul Mohd; Amil, Norhaniza; Hussain, Dini Fajrina Mohd; Lee, Vernon; Hosaini, Puteri Nurafidah; Shaharom, Suhana; Yusoff, Nur Amira Yasmin Mohd; Hoque, Hossain Mohammed Syedul; Chung, Jing Xiang; Sahani, Mazrura; Mohd Tahir, Norhayati; Juneng, Liew; Maulud, Khairul Nizam Abdul; Abdullah, Sharifah Mastura Syed; Fujii, Yusuke; Tohno, Susumu; Mizohata, Akira

2016-12-01

A comprehensive assessment of fine particulate matter (PM2.5) compositions during the Southeast Asia dry season is presented. Samples of PM2.5 were collected between 24 June and 14 September 2014 using a high-volume sampler. Water-soluble ions, trace species, rare earth elements, and a range of elemental carbon (EC) and organic carbon were analyzed. The characterization and source apportionment of PM2.5 were investigated. The results showed that the 24 h PM2.5 concentration ranged from 6.64 to 68.2 µg m-3. Meteorological driving factors strongly governed the diurnal concentration of aerosol, while the traffic in the morning and evening rush hours coincided with higher levels of CO and NO2. The correlation analysis for non sea-salt K+-EC showed that EC is potentially associated with biomass burning events, while the formation of secondary organic carbon had a moderate association with motor vehicle emissions. Positive matrix factorization (PMF) version 5.0 identified the sources of PM2.5: (i) biomass burning coupled with sea salt [I] (7%), (ii) aged sea salt and mixed industrial emissions (5%), (iii) road dust and fuel oil combustion (7%), (iv) coal-fired combustion (25%), (v) mineral dust (8%), (vi) secondary inorganic aerosol (SIA) coupled with F- (15%), and (vii) motor vehicle emissions coupled with sea salt [II] (24%). Motor vehicle emissions, SIA, and coal-fired power plant are the predominant sources contributing to PM2.5. The response of the potential source contribution function and Hybrid Single-Particle Lagrangian Integrated Trajectory backward trajectory model suggest that the outline of source regions were consistent to the sources by PMF 5.0.

Diagnosis of aged prescribed burning plumes impacting an urban area.

PubMed

Lee, Sangil; Kim, Hyeon K; Yan, Bo; Cobb, Charles E; Hennigan, Chris; Nichols, Sara; Chamber, Michael; Edgerton, Eric S; Jansen, John J; Hu, Yongtao; Zheng, Mei; Weber, Rodney J; Russell, Armistead G

2008-03-01

An unanticipated wind shift led to the advection of plumes from two prescribed burning sites that impacted Atlanta, GA, producing a heavy smoke event late in the afternoon on February 28, 2007. Observed PM2.5 concentrations increased to over 140 microg/m3 and O3 concentrations up to 30 ppb in a couple of hours, despite the late hour in February when photochemistry is less vigorous. A detailed investigation of PM2.5 chemical composition and source apportionment analysis showed that the increase in PM2.5 mass was driven mainly by organic carbon (OC). However, both results from source apportionment and an observed nonlinear relationship between OC and PM2.5 potassium (K) indicate that the increased OC was not due solely to primary emissions. Most of the OC was water-soluble organic carbon (WSOC) and was dominated by hydrophobic compounds. The data are consistent with large enhancements in isoprenoid (isoprene and monoterpenes) and other volatile organic compounds emitted from prescribed burning that led to both significant O3 and secondary organic aerosol (SOA) production. Formation of oligomers from oxidation products of isoprenoid compounds or condensation of volatile organic compounds (VOCs) with multiple functional groups emitted during prescribed burning appears to be a major component of the secondary organic contributor of the SOA. The results from this study imply that enhanced emissions due to the fire itself and elevated temperature in the burning region should be considered in air quality models (e.g., receptor and emission-based models) to assess impacts of prescribed burning emissions on ambient air quality.

Origin and variability in volatile organic compounds observed at an Eastern Mediterranean background site (Cyprus)

NASA Astrophysics Data System (ADS)

Debevec, Cécile; Sauvage, Stéphane; Gros, Valérie; Sciare, Jean; Pikridas, Michael; Stavroulas, Iasonas; Salameh, Thérèse; Leonardis, Thierry; Gaudion, Vincent; Depelchin, Laurence; Fronval, Isabelle; Sarda-Esteve, Roland; Baisnée, Dominique; Bonsang, Bernard; Savvides, Chrysanthos; Vrekoussis, Mihalis; Locoge, Nadine

2017-09-01

More than 7000 atmospheric measurements of over 60 C2 - C16 volatile organic compounds (VOCs) were conducted at a background site in Cyprus during a 1-month intensive field campaign held in March 2015. This exhaustive dataset consisted of primary anthropogenic and biogenic VOCs, including a wide range of source-specific tracers, and oxygenated VOCs (with various origins) that were measured online by flame ionization detection-gas chromatography and proton transfer mass spectrometry. Online submicron aerosol chemical composition was performed in parallel using an aerosol mass spectrometer. This study presents the high temporal variability in VOCs and their associated sources. A preliminary analysis of their time series was performed on the basis of independent tracers (NO, CO, black carbon), meteorological data and the clustering of air mass trajectories. Biogenic compounds were mainly attributed to a local origin and showed compound-specific diurnal cycles such as a daily maximum for isoprene and a nighttime maximum for monoterpenes. Anthropogenic VOCs as well as oxygenated VOCs displayed higher mixing ratios under the influence of continental air masses (i.e., western Asia), indicating that long-range transport significantly contributed to the VOC levels in the area. Source apportionment was then conducted on a database of 20 VOCs (or grouped VOCs) using a source receptor model. The positive matrix factorization and concentration field analyses were hence conducted to identify and characterize covariation factors of VOCs that were representative of primary emissions as well as chemical transformation processes. A six-factor PMF solution was selected, namely two primary biogenic factors (relative contribution of 43 % to the total mass of VOCs) for different types of emitting vegetation; three anthropogenic factors (short-lived combustion source, evaporative sources, industrial and evaporative sources; 21 % all together), identified as being either of local origin or from more distant emission zones (i.e., the south coast of Turkey); and a last factor (36 %) associated with regional background pollution (air masses transported both from the Western and Eastern Mediterranean regions). One of the two biogenic and the regional background factors were found to be the largest contributors to the VOC concentrations observed at our sampling site. Finally, a combined analysis of VOC PMF factors with source-apportioned organic aerosols (OAs) helped to better distinguish between anthropogenic and biogenic influences on the aerosol and gas phase compositions. The highest OA concentrations were observed when the site was influenced by air masses rich in semi-volatile OA (less oxidized aerosols) originating from the southwest of Asia, in contrast with OA factor contributions associated with the remaining source regions. A reinforcement of secondary OA formation also occurred due to the intense oxidation of biogenic precursors.

Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacier region of the southeastern Tibetan Plateau

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, Hewen; Kang, Shichang; Wang, Hailong

Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32μg m -3, respectively. Although the annual mean OC/EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a.s.l.) of Mt. Yulong. Strong photochemical reactions and local tourism activitiesmore » were likely the main factors inducing high OC/EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m 2g -1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol–climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50%) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.« less

26 CFR 1.861-8 - Computation of taxable income from sources within the United States and from other sources and...

Code of Federal Regulations, 2010 CFR

2010-04-01

... income. [Reserved]. For guidance, see § 1.861-8T(c)(1). (2) Apportionment based on assets. [Reserved.... [Reserved]. For guidance, see § 1.861-8T(d)(2). (e) Allocation and apportionment of certain deductions—(1... section. (2) Interest. [Reserved]. For guidance, see § 1.861-8T(e)(2). (3) Research and experimental...

Time-resolved analysis of particle emissions from residential biomass combustion - Emissions of refractory black carbon, PAHs and organic tracers

NASA Astrophysics Data System (ADS)

Nielsen, Ingeborg E.; Eriksson, Axel C.; Lindgren, Robert; Martinsson, Johan; Nyström, Robin; Nordin, Erik Z.; Sadiktsis, Ioannis; Boman, Christoffer; Nøjgaard, Jacob K.; Pagels, Joakim

2017-09-01

Time-resolved particle emissions from a conventional wood stove were investigated with aerosol mass spectrometry to provide links between combustion conditions, emission factors, mixing state of refractory black carbon and implications for organic tracer methods. The addition of a new batch of fuel results in low temperature pyrolysis as the fuel heats up, resulting in strong, short-lived, variable emission peaks of organic aerosol-containing markers of anhydrous sugars, such as levoglucosan (fragment at m/z 60). Flaming combustion results in emissions dominated by refractory black carbon co-emitted with minor fractions of organic aerosol and markers of anhydrous sugars. Full cycle emissions are an external mixture of larger organic aerosol-dominated and smaller thinly coated refractory black carbon particles. A very high burn rate results in increased full cycle mass emission factors of 66, 2.7, 2.8 and 1.3 for particulate polycyclic aromatic hydrocarbons, refractory black carbon, total organic aerosol and m/z 60, respectively, compared to nominal burn rate. Polycyclic aromatic hydrocarbons are primarily associated with refractory black carbon-containing particles. We hypothesize that at very high burn rates, the central parts of the combustion zone become air starved, leading to a locally reduced combustion temperature that reduces the conversion rates from polycyclic aromatic hydrocarbons to refractory black carbon. This facilitates a strong increase of polycyclic aromatic hydrocarbons emissions. At nominal burn rates, full cycle emissions based on m/z 60 correlate well with organic aerosol, refractory black carbon and particulate matter. However, at higher burn rates, m/z 60 does not correlate with increased emissions of polycyclic aromatic hydrocarbons, refractory black carbon and organic aerosol in the flaming phase. The new knowledge can be used to advance source apportionment studies, reduce emissions of genotoxic compounds and model the climate impacts of refractory black carbon, such as absorption enhancement by lensing.

Submicron particulate organic matter in the urban atmosphere: a new method for real-time measurement, molecular-level characterization and source apportionment

NASA Astrophysics Data System (ADS)

Müller, Markus; Eichler, Philipp; D'Anna, Barbara; Tan, Wen; Wisthaler, Armin

2017-04-01

We used a novel chemical analytical method for measuring submicron particulate organic matter in the atmosphere of three European cities (Innsbruck, Lyon, Valencia). Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) was used in combination with the "chemical analysis of aerosol online" (CHARON) inlet for detecting particulate organic compounds on-line (i.e. without filter pre-collection), in real-time (1-min time resolution), at ng m-3 concentrations, with molecular-level resolution (i.e. obtaining molecular weight and elemental composition information). The CHARON-PTR-ToF-MS system monitored molecular tracers associated with different particle sources including levoglucosan from biomass combustion, PAHs from vehicular traffic, nicotine from cigarette smoking, and monoterpene oxidation products secondarily formed from biogenic emissions. The tracer information was used for interpreting positive matrix factorization (PMF) data which allowed us to apportion the sources of submicron particulate organic matter in the different urban environments. This work was funded through the PIMMS ITN, which was supported by the European Commission's 7th Framework Programme under grant agreement number 287382.

Fine particulate matter (PM2.5) in Edmonton, Canada: Source apportionment and potential risk for human health.

PubMed

Bari, Md Aynul; Kindzierski, Warren B

2016-11-01

To design effective PM 2.5 control strategies in urban centers, there is a need to better understand local and remote sources influencing PM 2.5 levels and associated risk to public health. An investigation of PM 2.5 levels, sources and potential human health risk associated with trace elements in the PM 2.5 was undertaken in Edmonton over a 6-year period (September 2009-August 2015). The geometric mean PM 2.5 concentration of was 7.11 μg/m 3 (interquartile range, IQR = 4.83-10.08 μg/m 3 ). Positive matrix factorization (PMF) receptor modeling identified secondary organic aerosol (SOA) as the major contributor (2.2 μg/m 3 , 27%), followed by secondary nitrate (1.3 μg/m 3 , 17%) and secondary sulfate (1.2 μg/m 3 , 15%). Other local sources included transportation (1.1 μg/m 3 , 14%) and industry-related emissions (0.26 μg/m 3 , 3.4%), biomass burning (1.0 μg/m 3 , 13%) and soil (0.54 μg/m 3 , 6.8%). Five factors (i.e., SOA, secondary nitrate, secondary sulfate, transportation and biomass burning) contributed more than 85% to PM 2.5 for the 2009-2015 period. Geometric (arithmetic) mean and maximum ambient air concentrations for hazardous trace elements of public health concern in PM 2.5 during the study period were below United States regulatory agency chronic and acute health risk screening criteria. Carcinogenic and non-carcinogenic risk of trace elements and source-specific risk values were well below acceptable and safe levels of risks recommended by regulatory agencies. More work is needed to understand the origin of potential SOA and wintertime wood burning sources in Edmonton and the surrounding region and to apply source-risk apportionment using all available hazardous air pollutants (HAPs) including organic compounds to better interpret the potential health risk posed by various sources in urban areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Organic carbon at a remote site of the western Mediterranean Basin: sources and chemistry during the ChArMEx SOP2 field experiment

NASA Astrophysics Data System (ADS)

Michoud, Vincent; Sciare, Jean; Sauvage, Stéphane; Dusanter, Sébastien; Léonardis, Thierry; Gros, Valérie; Kalogridis, Cerise; Zannoni, Nora; Féron, Anaïs; Petit, Jean-Eudes; Crenn, Vincent; Baisnée, Dominique; Sarda-Estève, Roland; Bonnaire, Nicolas; Marchand, Nicolas; Langley DeWitt, H.; Pey, Jorge; Colomb, Aurélie; Gheusi, François; Szidat, Sonke; Stavroulas, Iasonas; Borbon, Agnès; Locoge, Nadine

2017-07-01

The ChArMEx (Chemistry and Aerosols Mediterranean Experiments) SOP2 (special observation period 2) field campaign took place from 15 July to 5 August 2013 in the western Mediterranean Basin at Ersa, a remote site in Cape Corse. During the campaign more than 80 volatile organic compounds (VOCs), including oxygenated species, were measured by different online and offline techniques. At the same time, an exhaustive description of the chemical composition of fine aerosols was performed with an aerosol chemical speciation monitor (ACSM). Low levels of anthropogenic VOCs (typically tens to hundreds of parts per trillion for individual species) and black carbon (0.1-0.9 µg m-3) were observed, while significant levels of biogenic species (peaking at the ppb level) were measured. Furthermore, secondary oxygenated VOCs (OVOCs) largely dominated the VOC speciation during the campaign, while organic matter (OM) dominated the aerosol chemical composition, representing 55 % of the total mass of non-refractory PM1 on average (average of 3.74 ± 1.80 µg m-3), followed by sulfate (27 %, 1.83 ± 1.06 µg m-3), ammonium (13 %, 0.90 ± 0.55 µg m-3) and nitrate (5 %, 0.31 ± 0.18 µg m-3). Positive matrix factorization (PMF) and concentration field (CF) analyses were performed on a database containing 42 VOCs (or grouped VOCs), including OVOCs, to identify the covariation factors of compounds that are representative of primary emissions or chemical transformation processes. A six-factor solution was found for the PMF analysis, including a primary and secondary biogenic factor correlated with temperature and exhibiting a clear diurnal profile. In addition, three anthropogenic factors characterized by compounds with various lifetimes and/or sources have been identified (long-lived, medium-lived and short-lived anthropogenic factors). The anthropogenic nature of these factors was confirmed by the CF analysis, which identified potential source areas known for intense anthropogenic emissions (north of Italy and southeast of France). Finally, a factor characterized by OVOCs of both biogenic and anthropogenic origin was found. This factor was well correlated with submicron organic aerosol (OA) measured by an aerosol chemical speciation monitor (ACSM), highlighting the close link between OVOCs and organic aerosols; the latter is mainly associated (96 %) with the secondary OA fraction. The source apportionment of OA measured by ACSM led to a three-factor solution identified as hydrogen-like OA (HOA), semi-volatile oxygenated OA (SV-OOA) and low volatility OOA (LV-OOA) for averaged mass concentrations of 0.13, 1.59 and 1.92 µg m-3, respectively. A combined analysis of gaseous PMF factors with inorganic and organic fractions of aerosols helped distinguish between anthropogenic continental and biogenic influences on the aerosol- and gas-phase compositions.

Source apportionment of 1 h semi-continuous data during the 2005 Study of Organic Aerosols in Riverside (SOAR) using positive matrix factorization

NASA Astrophysics Data System (ADS)

Eatough, Delbert J.; Grover, Brett D.; Woolwine, Woods R.; Eatough, Norman L.; Long, Russell; Farber, Robert

Positive matrix factorization (PMF2) was used to elucidate sources of fine particulate material (PM 2.5) for a study conducted during July and August 2005, in Riverside, CA. One-hour averaged semi-continuous measurements were made with a suite of instruments to provide PM 2.5 mass and chemical composition data. Total PM 2.5 mass concentrations (non-volatile plus semi-volatile) were measured with an R&P filter dynamic measurement system (FDMS TEOM) and a conventional TEOM monitor was used to measure non-volatile mass concentrations. PM 2.5 chemical species monitors included a dual-oven Sunset monitor to measure both non-volatile and semi-volatile carbonaceous material, an ion chromatographic-based monitor to measure sulfate and nitrate and an Anderson Aethalometer to measure black carbon (BC). Gas phase data including CO, NO 2, NO x and O 3 were also collected during the sampling period. In addition, single-particle measurements were made using aerosol time-of-flight mass spectrometry (ATOFMS). Twenty different single-particle types consistent with those observed in previous ATOFMS studies in Riverside were identified for the PMF2 analysis. Finally, time-of-flight aerosol mass spectrometry (ToF-AMS) provided data on markers of primary and secondary organic aerosol. Two distinct PMF2 analyses were performed. In analysis 1, all the data except for the ATOFMS and ToF-AMS data were used in an initial evaluation of sources at Riverside during the study. PMF2 was able to identify six factors from the data set corresponding to both primary and secondary sources, primarily from automobile emissions, diesel emissions, secondary nitrate formation, a secondary photochemical associated source, organic emissions and Basin transported pollutants. In analysis 2, the ATOFMS and ToF-AMS data were included in the analysis. In the second analysis, PMF2 was able to identify 16 factors with a variety of both primary and secondary factors being identified, corresponding to both primary and secondary material from both anthropogenic and natural sources. Based on relationships with Basin meteorology, the PMF identified source profiles and diurnal patterns in the source concentrations, sources were identified as being of local origin or resulting from transport of pollutants across the Basin due to onshore flow. Good agreement was observed between the PMF2 predicted mass and the FDMS measured mass for both analyses.

High-resolution sampling and analysis of ambient particulate matter in the Pearl River Delta region of southern China: source apportionment and health risk implications

NASA Astrophysics Data System (ADS)

Zhou, Shengzhen; Davy, Perry K.; Huang, Minjuan; Duan, Jingbo; Wang, Xuemei; Fan, Qi; Chang, Ming; Liu, Yiming; Chen, Weihua; Xie, Shanju; Ancelet, Travis; Trompetter, William J.

2018-02-01

Hazardous air pollutants, such as trace elements in particulate matter (PM), are known or highly suspected to cause detrimental effects on human health. To understand the sources and associated risks of PM to human health, hourly time-integrated major trace elements in size-segregated coarse (PM2.5-10) and fine (PM2.5) particulate matter were collected at the industrial city of Foshan in the Pearl River Delta region, China. Receptor modeling of the data set by positive matrix factorization (PMF) was used to identify six sources contributing to PM2.5 and PM10 concentrations at the site. Dominant sources included industrial coal combustion, secondary inorganic aerosol, motor vehicles and construction dust along with two intermittent sources (biomass combustion and marine aerosol). The biomass combustion source was found to be a significant contributor to peak PM2.5 episodes along with motor vehicles and industrial coal combustion. Conditional probability function (CPF) analysis was applied to estimate the source locations using the PMF-resolved source contribution coupled with the surface wind direction data. Health exposure risk of hazardous trace elements (Pb, As, Si, Cr, Mn and Ni) and source-specific values were estimated. The total hazard quotient (HQ) of PM2.5 was 2.09, higher than the acceptable limit (HQ = 1). The total carcinogenic risk (CR) was 3.37 × 10-3 for PM2.5, which was 3 times higher than the least stringent limit (1.0 × 10-4). Among the selected trace elements, As and Pb posed the highest non-carcinogenic and carcinogenic risks to human health, respectively. In addition, our results show that the industrial coal combustion source is the dominant non-carcinogenic and carcinogenic risk contributor, highlighting the need for stringent control of this source. This study provides new insight for policy makers to prioritize sources in air quality management and health risk reduction.

Trends in PM2.5 emissions, concentrations and apportionments in Detroit and Chicago

NASA Astrophysics Data System (ADS)

Milando, Chad; Huang, Lei; Batterman, Stuart

2016-03-01

PM2.5 concentrations throughout much of the U.S. have decreased over the last 15 years, but emissions and concentration trends can vary by location and source type. Such trends should be understood to inform air quality management and policies. This work examines trends in emissions, concentrations and source apportionments in two large Midwest U.S. cities, Detroit, Michigan, and Chicago, Illinois. Annual and seasonal trends were investigated using National Emission Inventory (NEI) data for 2002 to 2011, speciated ambient PM2.5 data from 2001 to 2014, apportionments from positive matrix factorization (PMF) receptor modeling, and quantile regression. Over the study period, county-wide data suggest emissions from point sources decreased (Detroit) or held constant (Chicago), while emissions from on-road mobile sources were constant (Detroit) or increased (Chicago), however changes in methodology limit the interpretation of inventory trends. Ambient concentration data also suggest source and apportionment trends, e.g., annual median concentrations of PM2.5 in the two cities declined by 3.2-3.6%/yr (faster than national trends), and sulfate concentrations (due to coal-fired facilities and other point source emissions) declined even faster; in contrast, organic and elemental carbon (tracers of gasoline and diesel vehicle exhaust) declined more slowly or held constant. The PMF models identified nine sources in Detroit and eight in Chicago, the most important being secondary sulfate, secondary nitrate and vehicle emissions. A minor crustal dust source, metals sources, and a biomass source also were present in both cities. These apportionments showed that the median relative contributions from secondary sulfate sources decreased by 4.2-5.5% per year in Detroit and Chicago, while contributions from metals sources, biomass sources, and vehicles increased from 1.3 to 9.2% per year. This first application of quantile regression to trend analyses of speciated PM2.5 data reveals that source contributions to PM2.5 varied as PM2.5 concentrations decreased, and that the fraction of PM2.5 due to emissions from vehicles and other local emissions has increased. Each data source has uncertainties, but emissions, monitoring and PMF data provide complementary information that can help to discern trends and identify contributing sources. Study results emphasize the need to target specific sources in policies and regulations aimed at decreasing PM2.5 concentrations in urban areas.

Evolution of Submicrometer Organic Aerosols during a Complete Residential Coal Combustion Process.

PubMed

Zhou, Wei; Jiang, Jingkun; Duan, Lei; Hao, Jiming

2016-07-19

In the absence of particulate matter (PM) control devices, residential coal combustion contributes significantly to ambient PM pollution. Characterizing PM emissions from residential coal combustion with high time resolution is beneficial for developing control policies and evaluating the environmental impact of PM. This study reports the evolution of submicrometer organic aerosols (OA) during a complete residential coal combustion process, that is, from fire start to fire extinction. Three commonly used coal types (bituminous, anthracite, and semicoke coals) were evaluated in a typical residential stove in China. For all three types of coal, the OA emission exhibited distinct characteristics in the four stages, that is, ignition, fierce combustion, relatively stable combustion, and ember combustion. OA emissions during the ignition stage accounted for 58.2-85.4% of the total OA emission of a complete combustion process. The OA concentration decreased rapidly during the fierce combustion stage and remained low during the relatively stable combustion stage. During these two stages, a significant ion peak of m/z 73 from organic acids were observed. The degree of oxidation of the OA increased from the first stage to the last stage. Implications for ambient OA source-apportionment and residential PM emission characterization and control are discussed.

A modified receptor model for source apportionment of heavy metal pollution in soil.

PubMed

Huang, Ying; Deng, Meihua; Wu, Shaofu; Japenga, Jan; Li, Tingqiang; Yang, Xiaoe; He, Zhenli

2018-07-15

Source apportionment is a crucial step toward reduction of heavy metal pollution in soil. Existing methods are generally based on receptor models. However, overestimation or underestimation occurs when they are applied to heavy metal source apportionment in soil. Therefore, a modified model (PCA-MLRD) was developed, which is based on principal component analysis (PCA) and multiple linear regression with distance (MLRD). This model was applied to a case study conducted in a peri-urban area in southeast China where soils were contaminated by arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). Compared with existing models, PCA-MLRD is able to identify specific sources and quantify the extent of influence for each emission. The zinc (Zn)-Pb mine was identified as the most important anthropogenic emission, which affected approximately half area for Pb and As accumulation, and approximately one third for Cd. Overall, the influence extent of the anthropogenic emissions decreased in the order of mine (3 km) > dyeing mill (2 km) ≈ industrial hub (2 km) > fluorescent factory (1.5 km) > road (0.5 km). Although algorithm still needs to improved, the PCA-MLRD model has the potential to become a useful tool for heavy metal source apportionment in soil. Copyright © 2018 Elsevier B.V. All rights reserved.

Diagnostic Air Quality Model Evaluation of Source-Specific ...

EPA Pesticide Factsheets

Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004–February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of −0.55 μgC/m3 was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (−0.46 μgC/m3 on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others. The National Exposure Research L

Diagnostic air quality model evaluation of source-specific primary and secondary fine particulate carbon.

PubMed

Napelenok, Sergey L; Simon, Heather; Bhave, Prakash V; Pye, Havala O T; Pouliot, George A; Sheesley, Rebecca J; Schauer, James J

2014-01-01

Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004-February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of -0.55 μgC/m(3) was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (-0.46 μgC/m(3) on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others.

Fossil vs. non-fossil sources of fine carbonaceous aerosols in four Chinese cities during the extreme winter haze episode of 2013

NASA Astrophysics Data System (ADS)

Zhang, Y.-L.; Huang, R.-J.; El Haddad, I.; Ho, K.-F.; Cao, J.-J.; Han, Y.; Zotter, P.; Bozzetti, C.; Daellenbach, K. R.; Canonaco, F.; Slowik, J. G.; Salazar, G.; Schwikowski, M.; Schnelle-Kreis, J.; Abbaszade, G.; Zimmermann, R.; Baltensperger, U.; Prévôt, A. S. H.; Szidat, S.

2015-02-01

During winter 2013, extremely high concentrations (i.e., 4-20 times higher than the World Health Organization guideline) of PM2.5 (particulate matter with an aerodynamic diameter < 2.5 μm) mass concentrations (24 h samples) were found in four major cities in China including Xi'an, Beijing, Shanghai and Guangzhou. Statistical analysis of a combined data set from elemental carbon (EC), organic carbon (OC), 14C and biomass-burning marker measurements using Latin hypercube sampling allowed a quantitative source apportionment of carbonaceous aerosols. Based on 14C measurements of EC fractions (six samples each city), we found that fossil emissions from coal combustion and vehicle exhaust dominated EC with a mean contribution of 75 ± 8% across all sites. The remaining 25 ± 8% was exclusively attributed to biomass combustion, consistent with the measurements of biomass-burning markers such as anhydrosugars (levoglucosan and mannosan) and water-soluble potassium (K+). With a combination of the levoglucosan-to-mannosan and levoglucosan-to-K+ ratios, the major source of biomass burning in winter in China is suggested to be combustion of crop residues. The contribution of fossil sources to OC was highest in Beijing (58 ± 5%) and decreased from Shanghai (49 ± 2%) to Xi'an (38 ± 3%) and Guangzhou (35 ± 7%). Generally, a larger fraction of fossil OC was from secondary origins than primary sources for all sites. Non-fossil sources accounted on average for 55 ± 10 and 48 ± 9% of OC and total carbon (TC), respectively, which suggests that non-fossil emissions were very important contributors of urban carbonaceous aerosols in China. The primary biomass-burning emissions accounted for 40 ± 8, 48 ± 18, 53 ± 4 and 65 ± 26% of non-fossil OC for Xi'an, Beijing, Shanghai and Guangzhou, respectively. Other non-fossil sources excluding primary biomass burning were mainly attributed to formation of secondary organic carbon (SOC) from non-fossil precursors such as biomass-burning emissions. For each site, we also compared samples from moderately to heavily polluted days according to particulate matter mass. Despite a significant increase of the absolute mass concentrations of primary emissions from both fossil and non-fossil sources during the heavily polluted events, their relative contribution to TC was even decreased, whereas the portion of SOC was consistently increased at all sites. This observation indicates that SOC was an important fraction in the increment of carbonaceous aerosols during the haze episode in China.

Source apportionment of PM2.5 at the Lin'an regional background site in China with three receptor models

NASA Astrophysics Data System (ADS)

Deng, Junjun; Zhang, Yanru; Qiu, Yuqing; Zhang, Hongliang; Du, Wenjiao; Xu, Lingling; Hong, Youwei; Chen, Yanting; Chen, Jinsheng

2018-04-01

Source apportionment of fine particulate matter (PM2.5) were conducted at the Lin'an Regional Atmospheric Background Station (LA) in the Yangtze River Delta (YRD) region in China from July 2014 to April 2015 with three receptor models including principal component analysis combining multiple linear regression (PCA-MLR), UNMIX and Positive Matrix Factorization (PMF). The model performance, source identification and source contribution of the three models were analyzed and inter-compared. Source apportionment of PM2.5 was also conducted with the receptor models. Good correlations between the reconstructed and measured concentrations of PM2.5 and its major chemical species were obtained for all models. PMF resolved almost all masses of PM2.5, while PCA-MLR and UNMIX explained about 80%. Five, four and seven sources were identified by PCA-MLR, UNMIX and PMF, respectively. Combustion, secondary source, marine source, dust and industrial activities were identified by all the three receptor models. Combustion source and secondary source were the major sources, and totally contributed over 60% to PM2.5. The PMF model had a better performance on separating the different combustion sources. These findings improve the understanding of PM2.5 sources in background region.

Source Apportionment of Particle Bound Polycyclic Aromatic Hydrocarbons at an Industrial Location in Agra, India

PubMed Central

Lakhani, Anita

2012-01-01

16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were quantified in total suspended ambient particulate matter (TSPM) collected from an industrial site in Agra (India) using gas chromatography. The major industrial activities in Agra are foundries that previously used coal and coke as fuel in cupola furnaces. These foundries have now switched over to natural gas. In addition, use of compressed natural gas has also been promoted and encouraged in automobiles. This study attempts to apportion sources of PAH in the ambient air and the results reflect the advantages associated with the change of fuel. The predominant PAHs in TSPM include high molecular weight (HMW) congeners BghiP, DbA, IP, and BaP. The sum of 16 priority PAHs had a mean value of 72.7 ± 4.7 ng m−3. Potential sources of PAHs in aerosols were identified using diagnostic ratios and principal component analysis. The results reflect a blend of emissions from diesel and natural gas as the major sources of PAH in the city along with contribution from emission of coal, coke, and gasoline. PMID:22606062

Impact of aerosol particle sources on optical properties in urban, regional and remote areas in the north-western Mediterranean

NASA Astrophysics Data System (ADS)

Ealo, Marina; Alastuey, Andrés; Pérez, Noemí; Ripoll, Anna; Querol, Xavier; Pandolfi, Marco

2018-01-01

Further research is needed to reduce the existing uncertainties on the effect that specific aerosol particle sources have on light extinction and consequently on climate. This study presents a new approach that aims to quantify the mass scattering and absorption efficiencies (MSEs and MAEs) of different aerosol sources at urban (Barcelona - BCN), regional (Montseny - MSY) and remote (Montsec - MSA) background sites in the north-western (NW) Mediterranean. An analysis of source apportionment to the measured multi-wavelength light scattering (σsp) and absorption (σap) coefficients was performed by means of a multilinear regression (MLR) model for the periods 2009-2014, 2010-2014 and 2011-2014 at BCN, MSY and MSA respectively. The source contributions to PM10 mass concentration, identified by means of the positive matrix factorization (PMF) model, were used as dependent variables in the MLR model. With this approach we addressed both the effect that aerosol sources have on air quality and their potential effect on light extinction through the determination of their MSEs and MAEs. An advantage of the presented approach is that the calculated MSEs and MAEs take into account the internal mixing of atmospheric particles. Seven aerosol sources were identified at MSA and MSY, and eight sources at BCN. Mineral, aged marine, secondary sulfate, secondary nitrate and V-Ni bearing sources were common at the three sites. Traffic, industrial/metallurgy and road dust resuspension sources were isolated at BCN, whereas mixed industrial/traffic and aged organics sources were identified at MSY and MSA. The highest MSEs were observed for secondary sulfate (4.5 and 10.7 m2 g-1, at MSY and MSA), secondary nitrate (8.8 and 7.8 m2 g-1) and V-Ni bearing source (8 and 3.5 m2 g-1). These sources dominated the scattering throughout the year with marked seasonal trends. The V-Ni bearing source, originating mainly from shipping in the area under study, simultaneously contributed to both σsp and σap, being the second most efficient light-absorbing source in BCN (MAE = 0.9 m2 g-1). The traffic source at BCN and the industrial/traffic at MSY exhibited the highest MAEs (1.7 and 0.9 m2 g-1). These sources were major contributors to σap at BCN and MSY; however at MSA, secondary nitrate exerted the highest influence on σap (MAE = 0.4 m2 g-1). The sources which were predominantly composed of fine and relatively dark particles, such as industrial/traffic, aged organics and V-Ni, were simultaneously characterized by low single scattering albedo (SSA) and a high scattering Ångström exponent (SAE). Conversely, mineral and aged marine showed the lowest SAE and the highest SSA, being scattering the dominant process in the light extinction. The good agreement found between modelled and measured particle optical properties allowed the reconstruction of σsp and σap long-term series over the period 2004-2014 at MSY. Significant decreasing trends were found for the modelled σsp and σap (-4.6 and -4.1 % yr-1).

Elemental Mixing State of Aerosol Particles Collected in Central Amazonia during GoAmazon2014/15

DOE PAGES

Fraund, Matthew; Pham, Don; Bonanno, Daniel; ...

2017-09-15

Two complementary techniques, Scanning Transmission X-ray Microscopy/Near Edge Fine Structure spectroscopy (STXM/NEXAFS) and Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX), have been quantitatively combined to characterize individual atmospheric particles. This pair of techniques was applied to particle samples at three sampling sites (ATTO, ZF2, and T3) in the Amazon basin as part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign during the dry season of 2014. The combined data was subjected to k-means clustering using mass fractions of the following elements: C, N, O, Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Ni, andmore » Zn. Cluster analysis identified 12 particle types, across different sampling sites and particle sizes. Samples from the remote Amazon Tall Tower Observatory (ATTO, also T0a) exhibited less cluster variety and fewer anthropogenic clusters than samples collected at the sites nearer to the Manaus metropolitan region, ZF2 (also T0t) or T3. Samples from the ZF2 site contained aged/anthropogenic clusters not readily explained by transport from ATTO or Manaus, possibly suggesting the effects of long range atmospheric transport or other local aerosol sources present during sampling. In addition, this data set allowed for recently established diversity parameters to be calculated. All sample periods had high mixing state indices (χ) that were >0.8. Two individual particle diversity (D i) populations were observed, with particles <0.5 μm having a D i of ~2.4 and >0.5 μm particles having a D i of ~3.6, which likely correspond to fresh and aged aerosols respectively. The diversity parameters determined by the quantitative method presented here will serve to aid in the accurate representation of aerosol mixing state, source apportionment, and aging in both less polluted and more industrialized environments in the Amazon Basin.« less

Elemental Mixing State of Aerosol Particles Collected in Central Amazonia during GoAmazon2014/15

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraund, Matthew; Pham, Don; Bonanno, Daniel

Two complementary techniques, Scanning Transmission X-ray Microscopy/Near Edge Fine Structure spectroscopy (STXM/NEXAFS) and Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX), have been quantitatively combined to characterize individual atmospheric particles. This pair of techniques was applied to particle samples at three sampling sites (ATTO, ZF2, and T3) in the Amazon basin as part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign during the dry season of 2014. The combined data was subjected to k-means clustering using mass fractions of the following elements: C, N, O, Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Ni, andmore » Zn. Cluster analysis identified 12 particle types, across different sampling sites and particle sizes. Samples from the remote Amazon Tall Tower Observatory (ATTO, also T0a) exhibited less cluster variety and fewer anthropogenic clusters than samples collected at the sites nearer to the Manaus metropolitan region, ZF2 (also T0t) or T3. Samples from the ZF2 site contained aged/anthropogenic clusters not readily explained by transport from ATTO or Manaus, possibly suggesting the effects of long range atmospheric transport or other local aerosol sources present during sampling. In addition, this data set allowed for recently established diversity parameters to be calculated. All sample periods had high mixing state indices (χ) that were >0.8. Two individual particle diversity (D i) populations were observed, with particles <0.5 μm having a D i of ~2.4 and >0.5 μm particles having a D i of ~3.6, which likely correspond to fresh and aged aerosols respectively. The diversity parameters determined by the quantitative method presented here will serve to aid in the accurate representation of aerosol mixing state, source apportionment, and aging in both less polluted and more industrialized environments in the Amazon Basin.« less

Wintertime aerosol chemical composition and source apportionment of the organic fraction across Ireland

NASA Astrophysics Data System (ADS)

Ovadnevaite, J.; Lin, C.; Ceburnis, D.; Huang, R. J. J.; O'Dowd, C. D. D.

2017-12-01

A national wide characterization of PM1 was studied for the first time using a high-time resolution Aerosol Chemical Speciation Monitor (ACSM) and Aethalometer in Ireland during the heating season. Dublin, the capital of Ireland, is the most polluted area with an average PM1 of 7.6 μg/m3, with frequent occurrence of peak concentration over 200 μg/m3 primarily due to solid fuels burning, while Mace Head, in the west coast, is least polluted with an average PM1 of 0.8 μg/m3 due to the distance from the emission sources. The organic aerosol is the most dominant species across Ireland, contributing 65%, 58%, 32%, 33% to total PM1 mass in Dublin, Birr, Carnsore Point, and Mace Head, respectively. Birr, a small town in the midland of Ireland, has comparable PM1 levels (4.8 μg/m3) and similar chemical compositions with that in Dublin. Carnsore Point, on the southeast coast, has similar composition with that at Mace Head, but nearly 3 times the levels of PM1 mass due to its relative closeness to other European countries. Positive matrix factorization (PMF) with the multi-linear engine (ME-2) was performed on the organic matrix to quantify the contribution of factor candidates. Peat burning was found to be the dominant factor across Ireland, contributing more than 40% of the total organic mass in Dublin and Birr while OOA is dominant at rural Carnsore Point and Mace Head. Possible geographic origins of PM1 species and organic factors using polar plots were explored. The findings of solid fuels burning (primarily peat burning) driving the pollution episodes suggest an elimination or controlled emission of solid fuels burning would reduce PM1 by at least 50%.

Secondary organic aerosol origin in an urban environment: influence of biogenic and fuel combustion precursors.

PubMed

Minguillón, M C; Pérez, N; Marchand, N; Bertrand, A; Temime-Roussel, B; Agrios, K; Szidat, S; van Drooge, B; Sylvestre, A; Alastuey, A; Reche, C; Ripoll, A; Marco, E; Grimalt, J O; Querol, X

2016-07-18

Source contributions of organic aerosol (OA) are still not fully understood, especially in terms of quantitative distinction between secondary OA formed from anthropogenic precursors vs. that formed from natural precursors. In order to investigate the OA origin, a field campaign was carried out in Barcelona in summer 2013, including two periods characterized by low and high traffic conditions. Volatile organic compound (VOC) concentrations were higher during the second period, especially aromatic hydrocarbons related to traffic emissions, which showed a marked daily cycle peaking during traffic rush hours, similarly to black carbon (BC) concentrations. Biogenic VOC (BVOC) concentrations showed only minor changes from the low to the high traffic period, and their intra-day variability was related to temperature and solar radiation cycles, although a decrease was observed for monoterpenes during the day. The organic carbon (OC) concentrations increased from the first to the second period, and the fraction of non-fossil OC as determined by (14)C analysis increased from 43% to 54% of the total OC. The combination of (14)C analysis and Aerosol Chemical Speciation Monitor (ACSM) OA source apportionment showed that the fossil OC was mainly secondary (>70%) except for the last sample, when the fossil secondary OC only represented 51% of the total fossil OC. The fraction of non-fossil secondary OC increased from 37% of total secondary OC for the first sample to 60% for the last sample. This enhanced formation of non-fossil secondary OA (SOA) could be attributed to the reaction of BVOC precursors with NOx emitted from road traffic (or from its nocturnal derivative nitrate that enhances night-time semi-volatile oxygenated OA (SV-OOA)), since NO2 concentrations increased from 19 to 42 μg m(-3) from the first to the last sample.

An integrated approach to assess heavy metal source apportionment in peri-urban agricultural soils.

PubMed

Huang, Ying; Li, Tingqiang; Wu, Chengxian; He, Zhenli; Japenga, Jan; Deng, Meihua; Yang, Xiaoe

2015-12-15

Three techniques (Isotope Ratio Analysis, GIS mapping, and Multivariate Statistical Analysis) were integrated to assess heavy metal pollution and source apportionment in peri-urban agricultural soils. The soils in the study area were moderately polluted with cadmium (Cd) and mercury (Hg), lightly polluted with lead (Pb), and chromium (Cr). GIS Mapping suggested Cd pollution originates from point sources, whereas Hg, Pb, Cr could be traced back to both point and non-point sources. Principal component analysis (PCA) indicated aluminum (Al), manganese (Mn), nickel (Ni) were mainly inherited from natural sources, while Hg, Pb, and Cd were associated with two different kinds of anthropogenic sources. Cluster analysis (CA) further identified fertilizers, waste water, industrial solid wastes, road dust, and atmospheric deposition as potential sources. Based on isotope ratio analysis (IRA) organic fertilizers and road dusts accounted for 74-100% and 0-24% of the total Hg input, while road dusts and solid wastes contributed for 0-80% and 19-100% of the Pb input. This study provides a reliable approach for heavy metal source apportionment in this particular peri-urban area, with a clear potential for future application in other regions. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of a source apportionment model in consideration of volatile organic compounds in an urban stream

USGS Publications Warehouse

Asher, W.E.; Luo, W.; Campo, K.W.; Bender, D.A.; Robinson, K.W.; Zogorski, J.S.; Pankow, J.F.

2007-01-01

Position-dependent concentrations of trichloroethylene and methyl-tert-butyl ether are considered for a 2.81-km section of the Aberjona River in Massachusetts, USA. This river flows through Woburn and Winchester (Massachusetts, USA), an area that is highly urbanized, has a long history of industrial activities dating to the early 1800s, and has gained national attention because of contamination from chlorinated solvent compounds in Woburn wells G and H. The river study section is in Winchester and begins approximately five stream kilometers downstream from the Woburn wells superfund site. Approximately 300 toxic release sites are documented in the watershed upstream from the terminus of the study section. The inflow to the river study section is considered one source of contamination. Other sources are the atmosphere, a tributary flow, and groundwater flows entering the river; the latter are categorized according to stream zone (1, 2, 3, etc.). Loss processes considered include outflows to groundwater and water-to-atmosphere transfer of volatile compounds. For both trichloroethylene and methyl-rerf-butyl ether, degradation is neglected over the timescale of interest. Source apportionment fractions with assigned values ??inflow, ??1, ??2, ??3, etc. are tracked by a source apportionment model. The strengths of the groundwater and tributary sources serve as fitting parameters when minimizing a reduced least squares statistic between water concentrations measured during a synoptic study in July 2001 versus predictions from the model. The model fits provide strong evidence of substantial unknown groundwater sources of trichloroethylene and methyl-tert-butyl ether amounting to tens of grams per day of trichloroethylene and methyl-tert-butyl ether in the river along the study section. Modeling in a source apportionment manner can be useful to water quality managers allocating limited resources for remediation and source control. ?? 2007 SETAC.

A clustering algorithm for sample data based on environmental pollution characteristics

NASA Astrophysics Data System (ADS)

Chen, Mei; Wang, Pengfei; Chen, Qiang; Wu, Jiadong; Chen, Xiaoyun

2015-04-01

Environmental pollution has become an issue of serious international concern in recent years. Among the receptor-oriented pollution models, CMB, PMF, UNMIX, and PCA are widely used as source apportionment models. To improve the accuracy of source apportionment and classify the sample data for these models, this study proposes an easy-to-use, high-dimensional EPC algorithm that not only organizes all of the sample data into different groups according to the similarities in pollution characteristics such as pollution sources and concentrations but also simultaneously detects outliers. The main clustering process consists of selecting the first unlabelled point as the cluster centre, then assigning each data point in the sample dataset to its most similar cluster centre according to both the user-defined threshold and the value of similarity function in each iteration, and finally modifying the clusters using a method similar to k-Means. The validity and accuracy of the algorithm are tested using both real and synthetic datasets, which makes the EPC algorithm practical and effective for appropriately classifying sample data for source apportionment models and helpful for better understanding and interpreting the sources of pollution.

Chemical apportionment of aerosol optical properties during the Asia-Pacific Economic Cooperation summit in Beijing, China

NASA Astrophysics Data System (ADS)

Han, Tingting; Xu, Weiqi; Chen, Chen; Liu, Xingang; Wang, Qingqing; Li, Jie; Zhao, Xiujuan; Du, Wei; Wang, Zifa; Sun, Yele

2015-12-01

We have investigated the chemical and optical properties of aerosol particles during the 2014 Asia-Pacific Economic Cooperation (APEC) summit in Beijing, China, using the highly time-resolved measurements by a high-resolution aerosol mass spectrometer and a cavity attenuated phase shift extinction monitor. The average (±σ) extinction coefficient (bext) and absorption coefficient (bap) were 186.5 (±184.5) M m-1 and 23.3 (±21.9) M m-1 during APEC, which were decreased by 63% and 56%, respectively, compared to those before APEC primarily due to strict emission controls. The aerosol composition and size distributions showed substantial changes during APEC; as a response, the mass scattering efficiency (MSE) of PM1 was decreased from 4.7 m2 g-1 to 3.5 m2 g-1. Comparatively, the average single-scattering albedo (SSA) remained relatively unchanged, illustrating the synchronous reductions of bext and bap during APEC. MSE and SSA were found to increase as function of the oxidation degree of organic aerosol (OA), indicating a change of aerosol optical properties during the aging processes. The empirical relationships between chemical composition and particle extinction were established using a multiple linear regression model. Our results showed the largest contribution of ammonium nitrate to particle extinction, accounting for 35.1% and 29.3% before and during APEC, respectively. This result highlights the important role of ammonium nitrate in the formation of severe haze pollution during this study period. We also observed very different optical properties of primary and secondary aerosol. Owing to emission controls in Beijing and surrounding regions and also partly the influences of meteorological changes, the average bext of secondary aerosol during APEC was decreased by 71% from 372.3 M m-1 to 108.5 M m-1, whereas that of primary aerosol mainly from cooking, traffic, and biomass burning emissions showed a smaller reduction from 136.7 M m-1 to 71.3 M m-1. As a result, the contribution of primary aerosol to particle extinction increased from 26.8% to 39.6%, elucidating an enhanced role of local primary sources in visibility deterioration during APEC. Further analysis of chemically resolved particle extinction showed that the extinction contributions of aerosol species varied greatly between different air masses but generally with ammonium nitrate, ammonium sulfate, and secondary OA being the three major contributors.

Bioavailability of Polycyclic Aromatic Hydrocarbons and their Potential Application in Eco-risk Assessment and Source Apportionment in Urban River Sediment

PubMed Central

Yang, Xunan; Yu, Liuqian; Chen, Zefang; Xu, Meiying

2016-01-01

Traditional risk assessment and source apportionment of sediments based on bulk polycyclic aromatic hydrocarbons (PAHs) can introduce biases due to unknown aging effects in various sediments. We used a mild solvent (hydroxypropyl-β-cyclodextrin) to extract the bioavailable fraction of PAHs (a-PAHs) from sediment samples collected in Pearl River, southern China. We investigated the potential application of this technique for ecological risk assessments and source apportionment. We found that the distribution of PAHs was associated with human activities and that the a-PAHs accounted for a wide range (4.7%–21.2%) of total-PAHs (t-PAHs), and high risk sites were associated with lower t-PAHs but higher a-PAHs. The correlation between a-PAHs and the sediment toxicity assessed using tubificid worms (r = −0.654, P = 0.021) was greater than that from t-PAH-based risk assessment (r = −0.230, P = 0.472). Moreover, the insignificant correlation between a-PAH content and mPEC-Q of low molecular weight PAHs implied the potiential bias of t-PAH-based risk assessment. The source apportionment from mild extracted fractions was consistent across different indicators and was in accordance with typical pollution sources. Our results suggested that mild extraction-based approaches reduce the potential error from aging effects because the mild extracted PAHs provide a more direct indicator of bioavailability and fresher fractions in sediments. PMID:26976450

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

2004-04-01

This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of September 2003 through February 2004. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. Results highlighted in this report include chemical fractionation of the organic fraction to quantify the ratio of organic mass to organic carbon (OM/OC). The average OM/OC ratio for the 31 samples analyzed so far is 1.89, ranging between 1.62 and 2.53, which is consistent with expectations for an atmospherically processed regional aerosol. Analysis of the single particle datamore » reveals that a on a particles in Pittsburgh consist of complex mixture of primary and secondary components. Approximately 79% of all particles measured with the instrument containing some form of carbon, with Carbonaceous Ammonium Nitrate (54.43%) being the dominant particle class. PMCAMx predictions were compared with data from more than 50 sites of the STN network located throughout the Eastern United States for the July 2001 period. OC and sulfate concentrations predicted by PMCAMx are within {+-}30% of the observed concentration at most of these sites. Spherical Aluminum Silicate particle concentrations (SAS) were used to estimate the contribution of primary coal emissions to fine particle levels at the central monitoring site. Primary emissions from coal combustion contribute on average 0.44 {+-} 0.3 {micro}g/m{sup 3} to PM{sub 2.5} at the site or 1.4 {+-} 1.3% of the total PM{sub 2.5} mass. Chemical mass balance analysis was performed to apportion the primary organic aerosol. About 70% of the primary OC emissions are from vehicular sources, with the gasoline contribution being on average three times greater than the diesel emissions in the summer.« less

Estimation of the local and long-range contributions to particulate matter levels using continuous measurements in a single urban background site

NASA Astrophysics Data System (ADS)

Diamantopoulou, Marianna; Skyllakou, Ksakousti; Pandis, Spyros N.

2016-06-01

The Particulate Matter Source Apportionment Technology (PSAT) algorithm is used together with PMCAMx, a regional chemical transport model, to develop a simple observation-based method (OBM) for the estimation of local and regional contributions of sources of primary and secondary pollutants in urban areas. We test the hypothesis that the minimum of the diurnal average concentration profile of the pollutant is a good estimate of the average contribution of long range transport levels. We use PMCAMx to generate "pseudo-observations" for four different European cities (Paris, London, Milan, and Dusseldorf) and PSAT to estimate the corresponding "true" local and regional contributions. The predictions of the proposed OBM are compared to the "true" values for different definitions of the source area. During winter, the estimates by the OBM for the local contributions to the concentrations of total PM2.5, primary pollutants, and sulfate are within 25% of the "true" contributions of the urban area sources. For secondary organic aerosol the OBM overestimates the importance of the local sources and it actually estimates the contributions of sources within 200 km from the receptor. During summer for primary pollutants and cities with low nearby emissions (ratio of emissions in an area extending 100 km from the city over local emissions lower than 10) the OBM estimates correspond to the city emissions within 25% or so. For cities with relatively high nearby emissions the OBM estimates correspond to emissions within 100 km from the receptor. For secondary PM2.5 components like sulfate and secondary organic aerosol the OBM's estimates correspond to sources within 200 km from the receptor. Finally, for total PM2.5 the OBM provides approximately the contribution of city emissions during the winter and the contribution of sources within 100 km from the receptor during the summer.

Chemical characteristics and source apportionment of indoor and outdoor fine particles observed in an urban environment in Korea

NASA Astrophysics Data System (ADS)

Heo, J.; Yi, S. M.

2016-12-01

Paired indoor-outdoor fine particulate matter (PM2.5) samples were collected at subway stations, underground shopping centers, and schools in Seoul metropolitan over a 4-year period between 2004 and 2007. Relationships between indoor and outdoor PM2.5 chemical species were determined and source contributions to indoor and outdoor PM2.5 mass were estimated using a positive matrix factorization (PMF) model. The PM2.5 samples were analyzed for major chemical components including organic carbon and elemental carbon, ions, and metals, and the results were used in the PMF model. The levels of the PM2.5 mass and its chemical components observed at the indoor sites were higher than those at the outdoor sites. Indoor levels of ions (i.e. sulfate, nitrate, ammonium), elemental carbon, and several metals (i.e. Fe, Zn, and Cu) were found to be significantly affected by outdoor sources. Very high indoor-to-outdoor mass ratio of these chemical components, in particular, were observed, representing the significant impacts of outdoor sources on indoor levels of them. Seven sources (secondary sulfate, secondary nitrate, mobile, biomass burning, roadway emissions, dust, and sea salt) were resolved by the PMF model at both of the indoor and outdoor sites. The secondary inorganic aerosol (i.e. secondary sulfate and nitrate) and the mobile sources were major contributors to the indoor and outdoor PM2.5, accounting for 47% and 27% of the outdoor PM2.5 and 40% and 25% of the indoor PM2.5, respectively. Furthermore, the contributions of the secondary inorganic aerosol and the mobile sources to the indoor PM2.5 were very comparable to its corresponding contributions to the outdoor PM2.5 levels. The spatial and temporal characteristics of each of sources resolved by the PMF model across the sites were examined using summary statistics, correlation analysis, and coefficient of variation and divergence analysis and the detailed results will be discussed in the presentation.

Concentrations, sources and geochemistry of airborne particulate matter at a major European airport.

PubMed

Amato, Fulvio; Moreno, Teresa; Pandolfi, Marco; Querol, Xavier; Alastuey, Andrés; Delgado, Ana; Pedrero, Manuel; Cots, Nuria

2010-04-01

Monitoring of aerosol particle concentrations (PM(10), PM(2.5), PM(1)) and chemical analysis (PM(10)) was undertaken at a major European airport (El Prat, Barcelona) for a whole month during autumn 2007. Concentrations of airborne PM at the airport were close to those at road traffic hotspots in the nearby Barcelona city, with means measuring 48 microg PM(10)/m(3), 21 microg PM(2.5)/m(3) and 17 microg PM(1)/m(3). Meteorological controls on PM at El Prat are identified as cleansing daytime sea breezes with abundant coarse salt particles, alternating with nocturnal land-sourced winds which channel air polluted by industry and traffic (PM(1)/PM(10) ratios > 0.5) SE down the Llobregat Valley. Chemical analyses of the PM(10) samples show that crustal PM is dominant (38% of PM(10)), followed by total carbon (OC + EC, 25%), secondary inorganic aerosols (SIA, 20%), and sea salt (6%). Local construction work for a new airport terminal was an important contributor to PM(10) crustal levels. Source apportionment modelling PCA-MLRA identifies five factors: industrial/traffic, crustal, sea salt, SIA, and K(+) likely derived from agricultural biomass burning. Whereas most of the atmospheric contamination concerning ambient air PM(10) levels at El Prat is not attributable directly to aircraft movement, levels of carbon are unusually high (especially organic carbon), as are metals possibly sourced from tyre detritus/smoke in runway dust (Ba, Zn, Mo) and from brake dust in ambient PM(10) (Cu, Sb), especially when the airport is at its most busy. We identify microflakes of aluminous alloys in ambient PM(10) filters derived from corroded fuselage and wings as an unequivocal and highly distinctive tracer for aircraft movement.

Chemical and geochemical composition of spring-summer Arctic aerosol collected at Ny Alesund, Svalbard Islands.

NASA Astrophysics Data System (ADS)

Udisti, Roberto; Becagli, Silvia; Caiazzo, Laura; Cappelletti, David; Giardi, Fabio; Grotti, Marco; Lucarelli, Franco; Moroni, Beatrice; Nava, Silvia; Severi, Mirko; Traversi, Rita

2017-04-01

Since March 2010, spring-summer (usually March - September) campaigns were continuously carried out at the Italian Gruvebadet Observatory, Ny Alesund, Svalbard Island. Aerosol was sampled by PM10 (daily) and 4-stage (4-day resolution) collector devices and size distribution was evaluated at 10 min resolution in the range 10 nm - 20 um (106 size classes by a TSI SMPS-APS integrated system). Six-year (2010-2015) PM10 and size-segregated (>10, 10-2.5, 2.5-1, < 1 um) filters were analyzed for ion composition (inorganic anions and cations, and selected organic anions by Ion Chromatography), metal content (major and trace metals, including Rare Earth Elements - REEs, by PIXE and ICP-MS), Pb isotopic composition (by ICP-MS) and Elemental and Organic Carbon (EC-OC) concentrations. The data set was elaborated by multi-parametric statistical analysis (Positive Matrix Factorization - PMF), in order to identifying and quantifying the contribution of the main anthropic and natural aerosol sources. Particular attention was spent in evaluating the anthropic contribution of nss-sulphate, nitrate, EC and heavy metals during the Arctic Haze in spring. The isotopic composition of Pb was used in identifying the source areas (North America, Greenland, North Europe, Siberia, Iceland) of anthropic emissions as a function of seasonality (different atmospheric circulation pathway). Crustal metals and, especially, REEs anomalies (with respect to the Chondrite-normalized profile) allowed characterizing the dust emissions from their Potential Source Areas (PSA). Biogenic markers (especially methane sulfonic acid - MSA - and bio-nss-sulphate) was used to obtain relevant information about the relationship between marine biogenic activity (primary productivity) and sea ice coverage and atmospheric conditions (irradiance, temperature, circulation pathways). The seasonal pattern of the nitrate deposition was also investigated. Chemical and geochemical measurements were compared with high-resolution size distribution and back-trajectory cluster analysis in order to understand the seasonal pattern of the contributions of long-range transport (particles distributed in the accumulation mode, especially in spring) as well as the occurrence of nucleation events (in the nano-metric range, especially in late spring-summer). Bibliography R. Udisti et al., "Sulfate source apportionment in the Ny-Alesund (Svalbard Islands) Arctic aerosol". Rend. Fis. Acc. Lincei, 2016, 27, S85-S94. doi: 10.1007/s12210-016-0517-7. B. Moroni et al., "Local vs. long range sources of aerosol particles upon Ny-Alesund (Svalbard Islands): mineral chemistry and geochemical records". Rend. Fis. Acc. Lincei, 2016, 27, S115-S127. DOI 10.1007/s12210-016-0533-7. S. Becagli et al., "Relationships linking prymary production, sea ice melting, and biogenic aerosol in the Arctic". Atmos. Environ., 2016, 136, 1-15. http://dx.doi.org/10.1016/j.atmosenv.2016.04.002. A. Bazzano et al., "Long-range transport of atmospheric lead reaching Ny Alesund: inter-annual and seasonal variations of potential source areas". Atmos. Environ., 2016, 139, 11-19. http://dx.doi.org/10.1016/j.atmosenv.2016.05.026.

Two Model-Based Methods for Policy Analyses of Fine Particulate Matter Control in China: Source Apportionment and Source Sensitivity

NASA Astrophysics Data System (ADS)

Li, X.; Zhang, Y.; Zheng, B.; Zhang, Q.; He, K.

2013-12-01

Anthropogenic emissions have been controlled in recent years in China to mitigate fine particulate matter (PM2.5) pollution. Recent studies show that sulfate dioxide (SO2)-only control cannot reduce total PM2.5 levels efficiently. Other species such as nitrogen oxide, ammonia, black carbon, and organic carbon may be equally important during particular seasons. Furthermore, each species is emitted from several anthropogenic sectors (e.g., industry, power plant, transportation, residential and agriculture). On the other hand, contribution of one emission sector to PM2.5 represents contributions of all species in this sector. In this work, two model-based methods are used to identify the most influential emission sectors and areas to PM2.5. The first method is the source apportionment (SA) based on the Particulate Source Apportionment Technology (PSAT) available in the Comprehensive Air Quality Model with extensions (CAMx) driven by meteorological predictions of the Weather Research and Forecast (WRF) model. The second method is the source sensitivity (SS) based on an adjoint integration technique (AIT) available in the GEOS-Chem model. The SA method attributes simulated PM2.5 concentrations to each emission group, while the SS method calculates their sensitivity to each emission group, accounting for the non-linear relationship between PM2.5 and its precursors. Despite their differences, the complementary nature of the two methods enables a complete analysis of source-receptor relationships to support emission control policies. Our objectives are to quantify the contributions of each emission group/area to PM2.5 in the receptor areas and to intercompare results from the two methods to gain a comprehensive understanding of the role of emission sources in PM2.5 formation. The results will be compared in terms of the magnitudes and rankings of SS or SA of emitted species and emission groups/areas. GEOS-Chem with AIT is applied over East Asia at a horizontal grid resolution of 0.5° (Lat) × 0.67° (Lon). WRF/CAMx with PSAT is applied to nested grids: 36-km × 36-km over China and 12-km × 12-km over northern China. These simulations are performed for 2006 and 2011. Beijing and northern Hebei are selected as representative receptor areas. Simulated surface concentrations by both models are evaluated with available observations in China. Focusing on inorganic aerosols (sulfate, nitrate and ammonium), preliminary SS results from GEOS-Chem/AIT at Beijing identify the top three major emission sectors to be agriculture, residential, and transportation in winter and agriculture, industry and power plant in summer. The top four source areas are northern Hebei, local, Neimenggu, and Liaoning in winter and northern Hebei, local, Shandong, and southern Hebei in summer. The synthesis of SS and SA for influential emission groups or areas from this work will provide a quantitative basis for emission control strategy development and policy making for PM2.5 control in China.

Smoke aerosol chemistry and aging of Siberian biomass burning emissions in a large aerosol chamber

NASA Astrophysics Data System (ADS)

Kalogridis, A.-C.; Popovicheva, O. B.; Engling, G.; Diapouli, E.; Kawamura, K.; Tachibana, E.; Ono, K.; Kozlov, V. S.; Eleftheriadis, K.

2018-07-01

Vegetation open fires constitute a significant source of particulate pollutants on a global scale and play an important role in both atmospheric chemistry and climate change. To better understand the emission and aging characteristics of smoke aerosols, we performed small-scale fire experiments using the Large Aerosol Chamber (LAC, 1800 m3) with a focus on biomass burning from Siberian boreal coniferous forests. A series of burn experiments were conducted with typical Siberian biomass (pine and debris), simulating separately different combustion conditions, namely, flaming, smoldering and mixed phase. Following smoke emission and dispersion in the combustion chamber, we investigated aging of aerosols under dark conditions. Here, we present experimental data on emission factors of total, elemental and organic carbon, as well as individual organic compounds, such as anhydrosugars, phenolic and dicarboxylic acids. We found that total carbon accounts for up to 80% of the fine mode (PM2.5) smoke aerosol. Higher PM2.5 emission factors were observed in the smoldering compared to flaming phase and in pine compared to debris smoldering phase. For low-temperature combustion, organic carbon (OC) contributed to more than 90% of total carbon, whereas elemental carbon (EC) dominated the aerosol composition in flaming burns with a 60-70% contribution to the total carbon mass. For all smoldering burns, levoglucosan (LG), a cellulose decomposition product, was the most abundant organic species (average LG/OC = 0.26 for pine smoldering), followed by its isomer mannosan or dehydroabietic acid (DA), an important constituent of conifer resin (DA/OC = 0.033). A levoglucosan-to-mannosan ratio of about 3 was observed, which is consistent with ratios reported for coniferous biomass and more generally softwood. The rates of aerosol removal for OC and individual organic compounds were investigated during aging in the chamber in terms of mass concentration loss rates over time under dark conditions and compared to the loss rate of EC. The latter is used as an inert tracer for estimating aerosol mechanical deposition and wall losses of the otherwise chemically conserved aerosol species. The OC/EC ratio increased with smoke aging for the flaming phase, suggesting a production/partitioning of organic compounds after emission. On the other hand, for smoldering burns OC/EC ratios decreased further with aging due to additional sinks of OC, other than those related to deposition and wall losses alone, such as evaporation of semi-volatile compounds. The chemical fingerprints of the major PM components of fresh and aged smoke found in this study are proposed to be used for the assessment of contributions from Siberian biomass burning to atmospheric pollution in source apportionment studies like those using molecular marker approaches.

Measurements and Analysis of Chemical Composition of Particulate Matter during High Pollution Events at Guanzhong Plain, China

NASA Astrophysics Data System (ADS)

Junji, C.

2017-12-01

Particulate matter pollution is a serious environmental problem which influencing air quality, regional and global climates, and human health. PM2.5 samples were collected at Guanzhong Plain with six sampling sites atdifferent cities in the year scale from 2012 to 2014. All of the six sites exhibited highest organic carbon (OC)and elemental carbon (EC) values in winter and lowest values in summer. OC correlates well with EC indicating similar emission sources. The contributions of secondary species SO42-, NO3- and NH4+ in total ions were greatest, and the high concentrations in winter were mainly due to emissions from coal combustion and biomass burning.During autumn the haze days were severest in Xi'an city with similar tendency of PM2.5 variations, and it was proved that biomass burning may be the main emission source of the regional pollution. In winter pollution episodes, the pollution patterns in Guanzhong Plain were similar which was resulted from strong secondary reactions and coal burning.Source apportionment using a positive matrix factorizationreceptor model indicates that on average secondary aerosol was the main source of PM2.5 (39.3%), followed by coal burning (17.3%), motor vehicle/industrial emissions (15.7%), fugitive dust (14.9%), and biomass burning (12.8%). The online, in situ measurement airborne species, especially the chemical composition of non-refectory submicron aerosol, during a heavyhaze-fog event, was analyzed in detailed.The formation of secondary sulfate and organic aerosol were observed during the event. The sulfur oxidation ratio (SOR), defined as sulfate/(SO2+sulfate) were mostly over 0.10, with a maximum of 0.30, when relative humidity > 80%. The aging product of organic aerosol (OA) were also observed in the event. The wet scattering coefficient was influenced by secondary sulfate, in the form of (NH4)2SO4, with contribution of 48.9% of wet particulate phase scattering. Thus decreased the visibility dramatically with a minimum of 128m. The current WRF-Chem model study suggested the secondary sulfate formation was essential to the increasing of sulfate concentration. The formation of secondary species was a decisive reason to form severe haze after fog event.

Advanced receptor modelling for the apportionment of road dust resuspension to atmospheric PM

NASA Astrophysics Data System (ADS)

Amato, F.; Pandolfi, M.; Escrig, A.; Querol, X.; Alastuey, A.; Pey, J.; Perez, N.; Hopke, P. K.

2009-04-01

Fugitive emissions from traffic resuspension can often represent an important source of atmospheric particulate matter in urban environments, especially when the scarce precipitations favour the accumulation of road dust. Resuspension of road dust can lead to high exposures to heavy metals, metalloids and mineral matter. Knowing the amount of its contribution to atmospheric PM is a key task for establishing eventual mitigation or preventive measures. Factor analysis techniques are widely used tools for atmospheric aerosol source apportionment, based on the mass conservation principle. Paatero and Tapper (1993) suggested the use of a Weighted Least Squares scheme with the aim of obtaining a minimum variance solution. Additionally they proposed to incorporate the basic physical constraint of non negativity, calling their approach Positive Matrix Factorization (PMF), which can be performed by the program PMF2 released by Paatero (1997). Nevertheless, Positive Matrix Factorization can be either solved with the Multilinear Engine (ME-2), a more flexible program, also developed by Paatero (1999), which can solve any model consisting in sum of products of unknowns. The main difference with PMF2 is that ME-2 does not solve only well-defined tasks, but its actions are defined in a "script file" written in a special-purpose programming language, allowing incorporating additional tasks such as data processing etc. Thus in ME-2 a priori information, e.g. chemical fingerprints can be included as auxiliary terms of the object function to be minimized. This feature of ME-2 make it especially suitable for source apportionment studies where some knowledge (chemical ratios, profiles, mass conservation etc) of involved sources is available. The aim of this study was to quantify the contribution of road dust resuspension in PM10, PM2.5 and PM1 data set from Barcelona (Spain). Given that recently the emission profile of local road dust was characterized (Amato et al., in press), authors show how to apply in ME-2 this knowledge to obtain a quantitative assessment of this source. The achievement of this objective permitted to show how is possible to improve a basic solution of PMF2 basing on an extended model. Results show that road dust resuspension accounted for 6.7 µg/m3 (16%) in PM10, 2.2 µg/m3 (8%) of PM2.5 and 0.3 µg/m3 (1%) of PM1, revealing that fugitive emissions were responsible of the 36%, 18% and 2% of total traffic emissions respectively in PM10, PM2.5 and PM1. Acknowledments: This work was funded by the Spanish Ministry of Science and Innovation (GRACCIE-SCD2007-00067)

Photochemical oxidation and changes in molecular composition of organic aerosol in the regional context

NASA Astrophysics Data System (ADS)

Robinson, Allen L.; Donahue, Neil M.; Rogge, Wolfgang F.

2006-02-01

This paper presents evidence that condensed-phase organic compounds are significantly oxidized in regional air masses and in locations affected by regional transport, especially during the summer. The core of the paper examines a large data set of ambient organic aerosol concentrations for removal of reactive compounds relative to less-reactive compounds. The approach allows visualization of both photochemistry and mixing of emissions from multiple sources in order to differentiate between the two phenomena. The focus is on hopanes and alkenoic acids, important markers for motor vehicle and cooking emissions. Ambient data from Pittsburgh, PA and the Southeastern United States contain evidence for significant photochemical oxidation of these compounds in the summertime. There is a strong seasonal pattern in the ratio of different hopanes to elemental carbon consistent with oxidation. In addition, measurements at rural sites indicate that hopanes are severely depleted in the regional air mass during the summer. Alkenoic acids also appear to be photochemically oxidized during the summertime; however, the oxidation rate appears to be much slower than that inferred from laboratory experiments. The significance of photochemistry is supported by rudimentary calculations which indicate substantial oxidation by OH radicals and ozone on a time scale of a few days or so, comparable to time scales for regional transport. Oxidation is non-linear; therefore it represents a very substantial complication to linear source apportionment techniques such as the Chemical Mass Balance model.

On the possibility of real time air quality and toxicology assessment using multi-wavelength photoacoustic spectroscopy

NASA Astrophysics Data System (ADS)

Ajtai, Tibor; Pinter, Mate; Utry, Noemi; Kiss-Albert, Gergely; Palagyi, Andrea; Manczinger, Laszlo; Vagvölgyi, Csaba; Szabo, Gabor; Bozoki, Zoltan

2016-04-01

In this study we present results of field measurement campaigns focusing on the in-situ characterization of absorption spectra and the health relevance of light absorbing carbonaceous (LAC) in the ambient. The absorption spectra is measured @ 266, 355, 532 and 1064 nm by our state-of-the-art four-wavelength photoacoustic instrument, while for health relevance the eco- cito and genotoxicity parameters were measured using standardized methodologies. We experimentally demonstrated a correlation between the toxicities and the measured absorption spectra quantified by its wavelength dependency. Based on this correlation, we present novel possibilities on real-time air quality monitoring. LAC is extensively studied not only because of its considerable climate effects but as a serious air pollutant too. Gradually increasing number of studies demonstrated experimentally that the health effect of LAC is more serious than it is expected based on its share in total atmospheric aerosol mass. Furthermore during many local pollution events LAC not only has dominancy but it is close to exclusivity. Altogether due to its climate and health effects many studies and proposed regulations focus on the physical, chemical and toxicological properties of LAC as well as on its source apportionment. Despites of its importance, there is not yet a widely accepted standard methodology for the real-time and selective identification of LAC. There are many different reasons of that: starting from its complex inherent physicochemical features including many unknown constituents, via masking effect of ambient on the inherent physicochemical properties taking place even in case of a short residence, ending with the lack of reliable instrumentation for its health or source relevant parameters. Therefore, the methodology and instrument development for selective and reliable identification of LAC is timely and important issues in climate and air quality researches. Recently, many studies demonstrated correlation between the chemical compositions and the absorption features of LAC which open up novel possibilities in real time source apportionment and in air quality monitoring.

Impact of secondary inorganic aerosol and road traffic at a suburban air quality monitoring station.

PubMed

Megido, L; Negral, L; Castrillón, L; Fernández-Nava, Y; Suárez-Peña, B; Marañón, E

2017-03-15

PM10 from a suburban site in the northwest of Spain was assessed using data from chemical determinations, meteorological parameters, aerosol maps and five-day back trajectories of air masses. Temporal variations in the chemical composition of PM10 were subsequently related to stationary/mobile local sources and long-range transport stemming from Europe and North Africa. The presence of secondary inorganic species (sulphates, nitrates and ammonium) in airborne particulate matter constituted one of the main focuses of this study. These chemical species formed 16.5% of PM10 on average, in line with other suburban background sites in Europe. However, a maximum of 47.8% of PM10 were recorded after several days under the influence of European air masses. Furthermore, the highest values of these three chemical species coincided with episodes of poor air circulation and influxes of air masses from Europe. The relationship between SO 4 2- and NH 4 + (R 2  = 0.57, p-value<0.01) was found to improve considerably in summer and spring (R 2  = 0.88 and R 2  = 0.87, respectively, p-value<0.01), whereas NO 3 - and NH 4 + (R 2  = 0.55, p-value<0.01) reproduced this pattern in winter (R 2  = 0.91, p-value<0.01). The application of a receptor model to the dataset led to the identification of notable apportionments due to road traffic and other types of combustion processes. In fact, large amounts of particulate matter were released to the atmosphere during episodes of biomass burning in forest fires. On isolated days, combustion was estimated to contribute up to 21.0 μg PM/m 3 (50.8% of PM10). The contribution from industrial processes to this source is also worth highlighting given the presence of Ni and Co in its profile. Furthermore, African dust outbreaks at the sampling site, characterised by an arc through the Atlantic Ocean, were usually associated with a higher concentration of Al 2 O 3 in PM10. Results evidenced the relevance of stationary (i.e., steelworks and thermal power station) and mobile sources in the air quality at the suburban site under study, with important apportionments of particulate matter coming from road traffic and as consequence of releasing precursor gases of secondary particles to the atmosphere. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of Organic Aerosol Formation and Apportionment in a polluted Megacity

NASA Astrophysics Data System (ADS)

Tsimpidi, A. P.; Karydis, V. A.; Zavala, M.; Lei, W.; Decarlo, P. F.; Ulbrich, I.; Jimenez, J. L.; Molina, L. T.; Pandis, S. N.

2009-04-01

Pollution from megacities and large urban areas is important not only for local effects on health, visibility, and ecosystems but also because of their collective influence on atmospheric chemistry and radiative forcing in regional and global scale. Organic species account for a large fraction of the submicron aerosol mass at most megacities. Urban areas are large sources of organic aerosols and their precursors. Nevertheless, the contributions of primary (POA) and secondary organic aerosol (SOA) have been difficult to quantify. In this study, new primary and secondary organic aerosol modules were added to PMCAMx, a three dimensional chemical transport model (Gaydos et al., 2007). The new modeling framework is based on the volatility basis-set approach (Lane et al., 2007): both primary and secondary organic components are assumed to be semivolatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The emission inventory is modified and the POA emissions are distributed by volatility based on dilution experiments (Robinson et al., 2007). PMCAMx is applied in the Mexico City Metropolitan Area during April 2003 and March 2006. The model predictions are compared with Aerodyne's Aerosol Mass Spectrometer (AMS) observations from the MCMA and MILAGRO campaigns respectively. Furthermore, the predicted concentrations over Mexico City are compared against measurements from a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) which was onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign (DeCarlo et al., 2008). The organic aerosol (OA) to CO ratio is used as an indicator in order to evaluate the photo-oxidation of the predicted OA after its horizontal and vertical advection. References Gaydos, T.M.; Pinder, R.W.; Koo, B.; Fahey, K.M.; Pandis, S.N., 2007. Development and application of a three-dimensional aerosol chemical transport model, PMCAMx. Atmospheric Environment 41, 2594-2611. Lane, T.E.; Donahue, N.M.; Pandis, S.N. 2008. Simulating Secondary Organic Aerosol Formation using the Votality Basis-Set Approach in a Chemical Transport Model, Atmospheric Environment 42, 7439-7451 Robinson, A.L.; Donahue, N.M.; Shrivastava, M.K.; Weitkamp, E.A.; Sage, A.M.; Grieshop, A.P.; Lane, T.E.; Pandis, S.N.; Pierce, J.R., 2007. Rethinking organic aerosols: semivolatile emissions and photochemical aging. Science 315, 1259-1262. DeCarlo, P.F.; Dunlea, E.J., Kimmel,et al., 2008. Fast Airborne Aerosol Size and Chemistry Measurements with the High Resolution Aerosol Mass Spectrometer during the MILAGRO Campaign, Atmos. Chem. Phys., 8, 4027-4048.

Preliminary Results of the first European Source Apportionment intercomparison for Receptor and Chemical Transport Models

NASA Astrophysics Data System (ADS)

Belis, Claudio A.; Pernigotti, Denise; Pirovano, Guido

2017-04-01

Source Apportionment (SA) is the identification of ambient air pollution sources and the quantification of their contribution to pollution levels. This task can be accomplished using different approaches: chemical transport models and receptor models. Receptor models are derived from measurements and therefore are considered as a reference for primary sources urban background levels. Chemical transport model have better estimation of the secondary pollutants (inorganic) and are capable to provide gridded results with high time resolution. Assessing the performance of SA model results is essential to guarantee reliable information on source contributions to be used for the reporting to the Commission and in the development of pollution abatement strategies. This is the first intercomparison ever designed to test both receptor oriented models (or receptor models) and chemical transport models (or source oriented models) using a comprehensive method based on model quality indicators and pre-established criteria. The target pollutant of this exercise, organised in the frame of FAIRMODE WG 3, is PM10. Both receptor models and chemical transport models present good performances when evaluated against their respective references. Both types of models demonstrate quite satisfactory capabilities to estimate the yearly source contributions while the estimation of the source contributions at the daily level (time series) is more critical. Chemical transport models showed a tendency to underestimate the contribution of some single sources when compared to receptor models. For receptor models the most critical source category is industry. This is probably due to the variety of single sources with different characteristics that belong to this category. Dust is the most problematic source for Chemical Transport Models, likely due to the poor information about this kind of source in the emission inventories, particularly concerning road dust re-suspension, and consequently the little detail about the chemical components of this source used in the models. The sensitivity tests show that chemical transport models show better performances when displaying a detailed set of sources (14) than when using a simplified one (only 8). It was also observed that an enhanced vertical profiling can improve the estimation of specific sources, such as industry, under complex meteorological conditions and that an insufficient spatial resolution in urban areas can impact on the capabilities of models to estimate the contribution of diffuse primary sources (e.g. traffic). Both families of models identify traffic and biomass burning as the first and second most contributing categories, respectively, to elemental carbon. The results of this study demonstrate that the source apportionment assessment methodology developed by the JRC is applicable to any kind of SA model. The same methodology is implemented in the on-line DeltaSA tool to support source apportionment model evaluation (http://source-apportionment.jrc.ec.europa.eu/).

Source apportionment of PM₁₀ and PM₂.₅ in a desert region in northern Chile.

PubMed

Jorquera, Héctor; Barraza, Francisco

2013-02-01

Estimating contributions of anthropogenic sources to ambient particulate matter (PM) in desert regions is a challenging issue because wind erosion contributions are ubiquitous, significant and difficult to quantify by using source-oriented, dispersion models. A receptor modeling analysis has been applied to ambient PM(10) and PM(2.5) measured in an industrial zone ~20 km SE of Antofagasta (23.63°S, 70.39°W), a midsize coastal city in northern Chile; the monitoring site is within a desert region that extends from northern Chile to southern Perú. Integrated 24-hour ambient samples of PM(10) and PM(2.5) were taken with Harvard Impactors; samples were analyzed by X Ray Fluorescence, ionic chromatography (NO(3)(-) and SO(4)(=)), atomic absorption (Na(+), K(+)) and thermal optical transmission for elemental and organic carbon determination. Receptor modeling was carried out using Positive Matrix Factorization (US EPA Version 3.0); sources were identified by looking at specific tracers, tracer ratios, local winds and wind trajectories computed from NOAA's HYSPLIT model. For the PM(2.5) fraction, six contributions were found - cement plant, 33.7 ± 1.3%; soil dust, 22.4 ± 1.6%; sulfates, 17.8 ± 1.7%; mineral stockpiles and brine plant, 12.4 ± 1.2%; Antofagasta, 8.5 ± 1.3% and copper smelter, 5.3 ± 0.8%. For the PM(10) fraction five sources were identified - cement plant, 38.2 ± 1.5%; soil dust, 31.2 ± 2.3%; mineral stockpiles and brine plant, 12.7 ± 1.7%; copper smelter, 11.5 ± 1.6% and marine aerosol, 6.5 ± 2.4%. Therefore local sources contribute to ambient PM concentrations more than distant sources (Antofagasta, marine aerosol) do. Soil dust is enriched with deposition of marine aerosol and calcium, sulfates and heavy metals from surrounding industrial activities. The mean contribution of suspended soil dust to PM(10) is 50 μg/m(3) and the peak daily value is 104 μg/m(3). For the PM(2.5) fraction, suspended soil dust contributes with an average of 9.3 μg/m(3) and a peak daily value of 31.5 μg/m(3). Copyright © 2012 Elsevier B.V. All rights reserved.

Chemical composition and sources of organic aerosols over London from the ClearfLo 2012 campaigns

NASA Astrophysics Data System (ADS)

Finessi, Emanuela; Holmes, Rachel; Hopkins, James; Lee, James; Harrison, Roy; Hamilton, Jacqueline

2014-05-01

Air quality in urban areas represents a major public health issue with around one third of the European population concentrated in cities and numbers expected to increase at global scale, particularly in developing countries. Particulate matter (PM) represents a primary threat for human health as numerous studies have confirmed the association between increased levels of cardiovascular and respiratory diseases with the exposure to PM. Despite considerable efforts made in improving air quality and progressively stricter emissions regulations, the PM concentrations have not changed much over the past decades for reasons that remain unclear, and highlight that studies on PM source apportionment are required for the formulation of effective policy. We investigated the chemical composition of organic aerosol (OA) collected during two intensive field campaigns held in winter and summer 2012 in the frame of the project Clean air for London (http://www.clearflo.ac.uk/). PM samples were collected both at a city background site (North Kensington) and at a rural site 50 km southeast of London (Detling) with 8 to 24 hours sampling schedule and analysed using off-line methods. Thermal-optical analysis was used to quantify OC-EC components while a suite of soft ionization mass spectrometric techniques was deployed for detailed chemical characterization. Liquid chromatography mass Spectrometry (LC-MSn) was mostly used for the simultaneous detection and quantification of various tracers for both primary and secondary OA sources. Well-established markers for wood burning primary OA like levoglucosan and azelaic acid were quantified together with various classes of nitroaromatics including methyl-nitrocatechols that are potential tracers for wood burning secondary OA. In addition, oxidation products of biogenic VOCs such as isoprene and monoterpenes were also quantified for both seasons and sites. A non-negligible contribution from biogenic SOA to urban OA was found in summertime measurements. It is hoped that these data will provide an insight into the sources and chemical processing of organic aerosol in London and help to evaluate the effects of this megacity on the surrounding areas.

Seasonal variation and light absorption property of carbonaceous aerosol in a typical glacieri region of the southeastern Tibetan Plateau

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, Hewen; Kang, Shichang; Wang, Hailong

2018-05-07

Deposition and accumulation of light-absorbing carbonaceous aerosol on glacier surfaces can alter the energy balance of glaciers. In this study, 2 years (December 2014 to December 2016) of continuous observations of carbonaceous aerosols in the glacierized region of the Mt. Yulong and Ganhaizi (GHZ) basin are analyzed. The average elemental carbon (EC) and organic carbon (OC) concentrations were 1.51±0.93 and 2.57±1.32 µg m−3, respectively. Although the annual mean OC ∕ EC ratio was 2.45±1.96, monthly mean EC concentrations during the post-monsoon season were even higher than OC in the high altitudes (approximately 5000 m a. s. l. ) of Mt. Yulong. Strong photochemical reactions and local tourism activities weremore » likely the main factors inducing high OC ∕ EC ratios in the Mt. Yulong region during the monsoon season. The mean mass absorption efficiency (MAE) of EC, measured for the first time in Mt. Yulong, at 632 nm with a thermal-optical carbon analyzer using the filter-based method, was 6.82±0.73 m2 g−1, comparable with the results from other studies. Strong seasonal and spatial variations of EC MAE were largely related to the OC abundance. Source attribution analysis using a global aerosol–climate model, equipped with a black carbon (BC) source tagging technique, suggests that East Asia emissions, including local sources, have the dominant contribution (over 50 %) to annual mean near-surface BC in the Mt. Yulong area. There is also a strong seasonal variation in the regional source apportionment. South Asia has the largest contribution to near-surface BC during the pre-monsoon season, while East Asia dominates the monsoon season and post-monsoon season. Results in this study have great implications for accurately evaluating the influences of carbonaceous matter on glacial melting and water resource supply in glacierization areas.« less

Indoor source apportionment in urban communities near industrial sites

NASA Astrophysics Data System (ADS)

Tunno, Brett J.; Dalton, Rebecca; Cambal, Leah; Holguin, Fernando; Lioy, Paul; Clougherty, Jane E.

2016-08-01

Because fine particulate matter (PM2.5) differs in chemical composition, source apportionment is frequently used for identification of relative contributions of multiple sources to outdoor concentrations. Indoor air pollution and source apportionment is often overlooked, though people in northern climates may spend up to 90% of their time inside. We selected 21 homes for a 1-week indoor sampling session during summer (July to September 2011), repeated in winter (January to March 2012). Elemental analysis was performed using inductively-coupled plasma mass spectrometry (ICP-MS), and factor analysis was used to determine constituent grouping. Multivariate modeling was run on factor scores to corroborate interpretations of source factors based on a literature review. For each season, a 5-factor solution explained 86-88% of variability in constituent concentrations. Indoor sources (i.e. cooking, smoking) explained greater variability than did outdoor sources in these industrial communities. A smoking factor was identified in each season, predicted by number of cigarettes smoked. Cooking factors were also identified in each season, explained by frequency of stove cooking and stovetop frying. Significant contributions from outdoor sources including coal and motor vehicles were also identified. Higher coal and secondary-related elemental concentrations were detected during summer than winter. Our findings suggest that source contributions to indoor concentrations can be identified and should be examined in relation to health effects.

Integrating Source Apportionment Tracers into a Bottom-up Inventory of Methane Emissions in the Barnett Shale Hydraulic Fracturing Region.

PubMed

Townsend-Small, Amy; Marrero, Josette E; Lyon, David R; Simpson, Isobel J; Meinardi, Simone; Blake, Donald R

2015-07-07

A growing dependence on natural gas for energy may exacerbate emissions of the greenhouse gas methane (CH4). Identifying fingerprints of these emissions is critical to our understanding of potential impacts. Here, we compare stable isotopic and alkane ratio tracers of natural gas, agricultural, and urban CH4 sources in the Barnett Shale hydraulic fracturing region near Fort Worth, Texas. Thermogenic and biogenic sources were compositionally distinct, and emissions from oil wells were enriched in alkanes and isotopically depleted relative to natural gas wells. Emissions from natural gas production varied in δ(13)C and alkane ratio composition, with δD-CH4 representing the most consistent tracer of natural gas sources. We integrated our data into a bottom-up inventory of CH4 for the region, resulting in an inventory of ethane (C2H6) sources for comparison to top-down estimates of CH4 and C2H6 emissions. Methane emissions in the Barnett are a complex mixture of urban, agricultural, and fossil fuel sources, which makes source apportionment challenging. For example, spatial heterogeneity in gas composition and high C2H6/CH4 ratios in emissions from conventional oil production add uncertainty to top-down models of source apportionment. Future top-down studies may benefit from the addition of δD-CH4 to distinguish thermogenic and biogenic sources.

Microbial water pollution: a screening tool for initial catchment-scale assessment and source apportionment.

PubMed

Kay, D; Anthony, S; Crowther, J; Chambers, B J; Nicholson, F A; Chadwick, D; Stapleton, C M; Wyer, M D

2010-11-01

The European Union Water Framework Directive requires that Management Plans are developed for individual River Basin Districts. From the point of view of faecal indicator organisms (FIOs), there is a critical need for screening tools that can provide a rapid assessment of the likely FIO concentrations and fluxes within catchments under base- and high-flow conditions, and of the balance ('source apportionment') between agriculture- and sewage-derived sources. Accordingly, the present paper reports on: (1) the development of preliminary generic models, using water quality and land cover data from previous UK catchment studies for assessing FIO concentrations, fluxes and source apportionment within catchments during the summer bathing season; (2) the calibration of national land use data, against data previously used in the models; and (3) provisional FIO concentration and source-apportionment assessments for England and Wales. The models clearly highlighted the crucial importance of high-flow conditions for the flux of FIOs within catchments. At high flow, improved grassland (and associated livestock) was the key FIO source; FIO loadings derived from catchments with high proportions of improved grassland were shown to be as high as from urbanized catchments; and in many rural catchments, especially in NW and SW England and Wales, which are important areas of lowland livestock (especially dairy) farming, ≥ 40% of FIOs was assessed to be derived from agricultural sources. In contrast, under base-flow conditions, when there was little or no runoff from agricultural land, urban (i.e. sewerage-related) sources were assessed to dominate, and even in rural areas the majority of FIOs were attributed to urban sources. The results of the study demonstrate the potential of this type of approach, particularly in light of climate change and the likelihood of more high-flow events, in underpinning informed policy development and prioritization of investment. Copyright © 2009 Elsevier B.V. All rights reserved.

Sediment source apportionment in Laurel Hill Creek, PA, using Bayesian chemical mass balance and isotope fingerprinting

USGS Publications Warehouse

Stewart, Heather; Massoudieh, Arash; Gellis, Allen C.

2015-01-01

A Bayesian chemical mass balance (CMB) approach was used to assess the contribution of potential sources for fluvial samples from Laurel Hill Creek in southwest Pennsylvania. The Bayesian approach provides joint probability density functions of the sources' contributions considering the uncertainties due to source and fluvial sample heterogeneity and measurement error. Both elemental profiles of sources and fluvial samples and 13C and 15N isotopes were used for source apportionment. The sources considered include stream bank erosion, forest, roads and agriculture (pasture and cropland). Agriculture was found to have the largest contribution, followed by stream bank erosion. Also, road erosion was found to have a significant contribution in three of the samples collected during lower-intensity rain events. The source apportionment was performed with and without isotopes. The results were largely consistent; however, the use of isotopes was found to slightly increase the uncertainty in most of the cases. The correlation analysis between the contributions of sources shows strong correlations between stream bank and agriculture, whereas roads and forest seem to be less correlated to other sources. Thus, the method was better able to estimate road and forest contributions independently. The hypothesis that the contributions of sources are not seasonally changing was tested by assuming that all ten fluvial samples had the same source contributions. This hypothesis was rejected, demonstrating a significant seasonal variation in the sources of sediments in the stream.

High-resolution sampling and analysis of air particulate matter in the Pear River Delta region of Southern China: source apportionment and health risk assessment

NASA Astrophysics Data System (ADS)

Zhou, S.; Day, P. K.; Wang, X.

2017-12-01

Hazardous air pollutants, such as trace elements in particulate matters (PM), are known or highly suspected to cause detrimental effects on human health. To understand the sources and associated risks of PM to human health, hourly time-integrated major trace elements in size-segregated coarse (PM10-2.5) and fine (PM2.5) particulate matter were collected and examined in an industrial city of Foshan in the Pearl River Delta region, China. Receptor modeling of the dataset by positive matrix factorization (PMF) was used to identify six sources contributing to PM2.5 and PM10 concentrations at the site. Dominant sources included industrial coal combustion, secondary inorganic aerosol, motor vehicles and construction dust along with two intermittent sources, biomass combustion and marine aerosol. The biomass combustion source was found to be a significant contributor to peak PM2.5 episodes along with motor vehicles and industrial coal combustion. Conditional probability function (CPF) was applied to estimate the local source effects from wind direction using the PMF-resolved source contribution coupled with the surface wind direction data. Health exposure risk for hazardous trace elements (Pb, As, Cr, Ni, Zn, V, Cu, Mn, Fe) and source-specific values were estimated. The total hazard quotient (total HQ =HI) of PM2.5 was 2.09, which is two times higher than the acceptable limit (HQ = 1). The total carcinogenic risk was 3.37*10-3 for PM2.5, which was three orders higher than the acceptable limit (i.e. 1.0*10-6). Among the selected trace elements, As and Pb posed the highest non-carcinogenic and carcinogenic risks for human health, respectively. In additional, our results showed that industrial coal combustion source was the dominant non-carcinogenic and carcinogenic risks contributor, highlighting the need for stringent control of this source. This study can provide new insight for policy makers to prioritize sources in air quality management and health risk reduction.

Examining the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol formation during the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee ground site

NASA Astrophysics Data System (ADS)

Budisulistiorini, S. H.; Li, X.; Bairai, S. T.; Renfro, J.; Liu, Y.; Liu, Y. J.; McKinney, K. A.; Martin, S. T.; McNeill, V. F.; Pye, H. O. T.; Nenes, A.; Neff, M. E.; Stone, E. A.; Mueller, S.; Knote, C.; Shaw, S. L.; Zhang, Z.; Gold, A.; Surratt, J. D.

2015-08-01

A suite of offline and real-time gas- and particle-phase measurements was deployed at Look Rock, Tennessee (TN), during the 2013 Southern Oxidant and Aerosol Study (SOAS) to examine the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formation. High- and low-time-resolution PM2.5 samples were collected for analysis of known tracer compounds in isoprene-derived SOA by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) and ultra performance liquid chromatography/diode array detection-electrospray ionization-high-resolution quadrupole time-of-flight mass spectrometry (UPLC/DAD-ESI-HR-QTOFMS). Source apportionment of the organic aerosol (OA) was determined by positive matrix factorization (PMF) analysis of mass spectrometric data acquired on an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Campaign average mass concentrations of the sum of quantified isoprene-derived SOA tracers contributed to ~ 9 % (up to 28 %) of the total OA mass, with isoprene-epoxydiol (IEPOX) chemistry accounting for ~ 97 % of the quantified tracers. PMF analysis resolved a factor with a profile similar to the IEPOX-OA factor resolved in an Atlanta study and was therefore designated IEPOX-OA. This factor was strongly correlated (r2 > 0.7) with 2-methyltetrols, C5-alkene triols, IEPOX-derived organosulfates, and dimers of organosulfates, confirming the role of IEPOX chemistry as the source. On average, IEPOX-derived SOA tracer mass was ~ 26 % (up to 49 %) of the IEPOX-OA factor mass, which accounted for 32 % of the total OA. A low-volatility oxygenated organic aerosol (LV-OOA) and an oxidized factor with a profile similar to 91Fac observed in areas where emissions are biogenic-dominated were also resolved by PMF analysis, whereas no primary organic aerosol (POA) sources could be resolved. These findings were consistent with low levels of primary pollutants, such as nitric oxide (NO ~ 0.03 ppb), carbon monoxide (CO ~ 116 ppb), and black carbon (BC ~ 0.2 μg m-3). Particle-phase sulfate is fairly correlated (r2 ~ 0.3) with both methacrylic acid epoxide (MAE)/hydroxymethyl-methyl-α-lactone (HMML)- (henceforth called methacrolein (MACR)-derived SOA tracers) and IEPOX-derived SOA tracers, and more strongly correlated (r2 ~ 0.6) with the IEPOX-OA factor, in sum suggesting an important role of sulfate in isoprene SOA formation. Moderate correlation between the MACR-derived SOA tracer 2-methylglyceric acid with sum of reactive and reservoir nitrogen oxides (NOy; r2 = 0.38) and nitrate (r2 = 0.45) indicates the potential influence of anthropogenic emissions through long-range transport. Despite the lack of a clear association of IEPOX-OA with locally estimated aerosol acidity and liquid water content (LWC), box model calculations of IEPOX uptake using the simpleGAMMA model, accounting for the role of acidity and aerosol water, predicted the abundance of the IEPOX-derived SOA tracers 2-methyltetrols and the corresponding sulfates with good accuracy (r2 ~ 0.5 and ~ 0.7, respectively). The modeling and data combined suggest an anthropogenic influence on isoprene-derived SOA formation through acid-catalyzed heterogeneous chemistry of IEPOX in the southeastern US. However, it appears that this process was not limited by aerosol acidity or LWC at Look Rock during SOAS. Future studies should further explore the extent to which acidity and LWC as well as aerosol viscosity and morphology becomes a limiting factor of IEPOX-derived SOA, and their modulation by anthropogenic emissions.

Verifying Sediment Fingerprinting Results with Known Mixtures

NASA Astrophysics Data System (ADS)

Gellis, A.; Gorman-Sanisaca, L.; Cashman, M. J.

2017-12-01

Sediment fingerprinting is a widely used approach to determine the specific sources of fluvial sediment within a watershed. It relies on the principle that potential sediment sources can be identified using a set of chemical tracers (or fingerprints), and comparison of these source fingerprints with fluvial (target) sediment allows for source apportionment of the fluvial sediment. There are numerous source classifications, fingerprints, and statistical approaches used in the literature to apportion sources of sediment. However, few of these studies have sought to test the method by creating controls on the ratio of sources in the target sediment. Without a controlled environment for inputs and outputs, such verification of results is ambiguous. Here, we generated artificial mixtures of source sediment from an agricultural/forested watershed in Virginia, USA (Smith Creek, 246 km2) to verify the apportionment results. Target samples were established from known mixtures of the four major sediment sources in the watershed (forest, pasture, cropland, and streambanks). The target samples were sieved to less than 63 microns and analyzed for elemental and isotopic chemistry. The target samples and source samples were run through the Sediment Source Assessment Tool (Sed_SAT) to verify if the statistical operations provided the correct apportionment. Sed_SAT uses a multivariate parametric approach to identify the minimum suite of fingerprints that discriminate the source areas and applies these fingerprints through an unmixng model to apportion sediment. The results of this sediment fingerprinting verification experiment will be presented in this session.

[Preliminary study of source apportionment of PM10 and PM2.5 in three cities of China during spring].

PubMed

Gao, Shen; Pan, Xiao-chuan; Madaniyazi, Li-na; Xie, Juan; He, Ya-hui

2013-09-01

To study source apportionment of atmospheric PM10 (particle matter ≤ 10 µm in aerodynamic diameter) and PM2.5 (particle matter ≤ 2.5 µm in aerodynamic diameter) in Beijing,Urumqi and Qingdao, China. The atmospheric particle samples of PM10 and PM2.5 collected from Beijing between May 17th and June 18th, 2005, from Urumqi between April 20th and June 1st, 2006 and from Qingdao between April 4th and May 15th, 2005, were detected to trace the source apportionment by factor analysis and enrichment factor methods. In Beijing, the source apportionment results derived from factor analysis model for PM10 were construction dust and soil sand dust (contributing rate of variance at 45.35%), industry dust, coal-combusted smoke and vehicle emissions (contributing rate at 31.83%), and biomass burning dust (13.57%). The main pollution element was Pb, while the content (median (minimum value-maximum value)was 0.216 (0.040-0.795) µg/m(3)) . As for PM2.5, the sources were construction dust and soil sand dust (38.86%), industry dust, coal-combusted smoke and vehicle emissions (25.73%), biomass burning dust (13.10%) and burning oil dust (11.92%). The main pollution element was Zn (0.365(0.126-0.808) µg/m(3)).In Urumqi, source apportionment results for PM10 were soil sand dust and coal-combusted dust(49.75%), industry dust, vehicle emissions and secondary particles dust (30.65%). The main characteristic pollution element was Cd (0.463(0.033-1.351) ng/m(3)). As for PM2.5, the sources were soil sand dust and coal-combusted dust (43.26%), secondary particles dust (22.29%), industry dust and vehicle emissions (20.50%). The main characteristic pollution element was As (14.599 (1.696-36.741) µg/m(3)).In Qingdao, source apportionment results for PM10 were construction dust (30.91%), vehicle emissions and industry dust (29.65%) and secondary particles dust (28.99%). The main characteristic pollution element was Pb (64.071 (5.846-346.831) µg/m(3)). As for PM2.5, the sources were secondary particles dust, industry dust and vehicle emissions (49.82%) and construction dust (33.71%). The main characteristic pollution element was Pb(57.340 (5.004-241.559) µg/m(3)).Enrichment factors of Zn, Pb, As and Cd in PM2.5 were higher than those in PM10 both in Beijing and Urumqi. The major sources of the atmospheric particles PM10 and PM2.5 in Beijing were cement dust from construction sites and sand dust from soil; while the major sources of those in Urumqi were pollution by smoke and sand dust from burning coal. The major sources of the atmospheric particles PM10 in Qingdao were cement dust from construction sites; however, the major sources of PM2.5 there were secondary particles dust, industry dust and vehicle emissions. According to our study, the heavy metal elements were likely to gather in PM2.5.

High time-resolved chemical compositions, sources and evolution for atmospheric submicron aerosols in the winter of Beijing

NASA Astrophysics Data System (ADS)

Min, H.; Hu, W.; Zheng, J.; Guo, S.; Wu, Y.; Zeng, L.; Lu, S.; Xie, S.; Zhang, Y.

2017-12-01

Severe regional haze problem in the megacity Beijing and surrounding areas has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, intensive campaigns were conducted in the winter of 2010 and 2013 at an urban site in Beijing. An Aerodyne high resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) was deployed to measure chemical components of PM1, coupled with multiple state of the art online instruments. In the winter of 2010, PM1 mass concentrations changed dramatically along with meteorological conditions. The high average fraction (58%) of primary species in PM1 indicated that primary emissions usually played a more important role. Based on the source apportionment results, 45% POA are from non-fossil sources, contributed by cooking OA and biomass burning OA (BBOA). Cooking OA, accounting for 13-24% of OA, is an important non-fossil carbon source in all years of Beijing and should not be neglected. The fossil sources of POA include hydrocarbon-like OA from vehicle emissions and coal combustion OA (CCOA). The CCOA and BBOA were the two main contributors (57% of OA) for the highest OA concentrations (>100 μg m-3). In the winter of 2013, OOA (MO-OOA and LO-OOA), accounted for 50% of PM1, while (OOA+SNA) contributed 60-80%, suggesting that secondary formation played an important role in the PM pollution. In the winter of 2010 higher OOA/Ox (= NO2 + O3) ratio (0.49 μg m-3 ppb-1) than these ratios from western cities (0.03-0.16 μg m-3 ppb-1) was observed, which may be due to the aqueous reaction or extra SOA formation contributed by semi-VOCs from various primary sources (e.g., BBOA or CCOA). However, aqueous chemistry resulting in efficient secondary formation during occasional periods with high relative humidity may also contribute substantially to haze in winter. CCOA was only identified in winter due to domestic heating. These results signified that the comprehensive management for biomass burning and coal combustion emissions is needed. Further strengthening the regional emission control of primary particulate and precursors of secondary species is expected.

The CSSIAR v.1.00 Software: A new tool based on SIAR to assess soil redistribution using Compound Specific Stable Isotopes

NASA Astrophysics Data System (ADS)

Sergio, de los Santos-Villalobos; Claudio, Bravo-Linares; dos Anjos Roberto, Meigikos; Renan, Cardoso; Max, Gibbs; Andrew, Swales; Lionel, Mabit; Gerd, Dercon

Soil erosion is one of the biggest challenges for food production around the world. Many techniques have been used to evaluate and mitigate soil degradation. Nowadays isotopic techniques are becoming a powerful tool to assess soil apportionment. One of the innovative techniques used is the Compound Specific Stable Isotopes (CSSI) analysis, which has been used to track down sediments and specify their sources by the isotopic signature of δ13 C in specific fatty acids. The application of this technique on soil apportionment has been recently developed, however there is a lack of user-friendly Software for data processing and interpretation. The aim of this article is to introduce a new open source tool for working with data sets generated by the use of the CSSI technique to assess soil apportionment, called the CSSIARv1.00 Software

Source contributions of urban PM2.5 in the Beijing-Tianjin-Hebei region: Changes between 2006 and 2013 and relative impacts of emissions and meteorology

NASA Astrophysics Data System (ADS)

Li, Xin; Zhang, Qiang; Zhang, Yang; Zheng, Bo; Wang, Kai; Chen, Ying; Wallington, Timothy J.; Han, Weijian; Shen, Wei; Zhang, Xiaoye; He, Kebin

2015-12-01

Anthropogenic emissions in China have been controlled for years to improve ambient air quality. However, severe haze events caused by atmospheric aerosols with aerodynamic diameter less than or equal to 2.5 μm (PM2.5) have continued to occur, especially in the Beijing-Tianjin-Hebei (BTH) region. The Chinese government has set an ambitious goal to reduce urban PM2.5 concentrations by 25% in BTH by 2017 relative to the 2012 levels. Source apportionment (SA) is necessary to the development of the effective emission control strategies. In this work, the Comprehensive Air Quality Model with extensions (CAMx) with the Particulate Source Apportionment Technology (PSAT) is applied to the China domain for the years 2006 and 2013. Ambient surface concentrations of PM2.5 and its components are generally well reproduced. To quantify the contributions of each emission category or region to PM2.5 in BTH, the total emissions are divided into 7 emission categories and 11 source regions. The source contributions determined in this work are generally consistent with results from previous work. In 2013, the industrial (44%) and residential (27%) sectors are the dominant contributors to urban PM2.5 in BTH. The residential sector is the largest contributor in winter; the industry sector dominates in other seasons. A slight increasing trend (+3% for industry and +6% for residential) is found in 2013 relative to 2006, necessitating more attention to these two sectors. Local emissions make the largest contribution (40%-60%) for all receptors. Change of source contribution of PM2.5 in Beijing and northern Hebei are dominate by change of local emission. However, for Tianjin, and central and southern Hebei, change of meteorology condition are as important as change of emission, because regional inflow in these areas is more important than in Beijing and northern Hebei and can increase under unfavorable weather conditions, indicating a strong need for regional joint emission control efforts. The results in this study enhance the quantitative understanding of the source-receptor relationships and provide an important basis for policymaking to advance the control of PM2.5 pollution in China.

Size-resolved source apportionment of particulate matter in urban Beijing during haze and non-haze episodes

NASA Astrophysics Data System (ADS)

Tian, S. L.; Pan, Y. P.; Wang, Y. S.

2015-03-01

More size-resolved chemical information is needed before the physicochemical characteristics and sources of airborne particles can be understood, but this information remains unavailable in most regions of China due to a paucity of measurement data. In this study, we report a one-year observation of various chemical species in size-segregated particle samples collected in urban Beijing, a mega city that experiences severe haze episodes. In addition to fine particles, the measured particle size distributions showed high concentrations of coarse particles during the haze periods. The abundance and chemical compositions of the particles in this study were temporally and spatially variable, with major contributions from organic matter and secondary inorganic aerosols. The contribution of the organic matter to the mass decreased from 37.9 to 33.1%, whereas the total contribution of SO42-, NO3- and NH4+ increased from 19.1 to 32.3% on non-haze and haze days, respectively. Due to heterogeneous reactions and hygroscopic growth, the peaks in the size distributions of organic carbon, SO42-, NO3-, NH4+, Cl-, K+ and Cu shifted from 0.43-0.65 μm on non-haze days to 0.65-1.1 μm on haze days. Although the size distributions are similar for the heavy metals Pb, Cd and Tl during the observation period, their concentrations increased by a factor of more than 1.5 on haze days compared with non-haze days. We found that NH4+ with a size range of 0.43-0.65 μm, SO42- and NO3- with a size range of 0.65-1.1 μm and Ca2+ with a size range of 5.8-9 μm as well as the meteorological factors of relative humidity and wind speed were responsible for the haze pollution when the visibility was less than 15 km. Source apportionment using positive matrix factorization identified six common sources: secondary inorganic aerosols (26.1% for fine particles vs. 9.5% for coarse particles), coal combustion (19 vs. 23.6%), primary emissions from vehicles (5.9 vs. 8.0%), biomass burning (8.5 vs. 2.9%), industrial pollution (6.3 vs. 8.5%) and mineral dust (16.1 vs. 35.1%). The first four factors were higher on haze days, while the latter factors were higher on non-haze days. The sources generally increased with decreasing size with the exception of mineral dust. However, two peaks were consistently found in the fine and coarse particles. The contributing sources also varied with the wind direction; coal and oil combustion products increased during southern flows, indicating that any mitigation strategy should consider the wind pattern, especially during the haze periods. The findings indicated that the PM2.5-based dataset is insufficient for the Chinese source control policy, and detailed size-resolved information is urgently needed to characterize the important sources in urban regions and better understand severe haze pollution.

Source Apportionment and Elemental Composition of PM2.5 and PM10 in Jeddah City, Saudi Arabia.

PubMed

Khodeir, Mamdouh; Shamy, Magdy; Alghamdi, Mansour; Zhong, Mianhua; Sun, Hong; Costa, Max; Chen, Lung-Chi; Maciejczyk, Polina

2012-07-01

This paper presents the first comprehensive investigation of PM2.5 and PM10 composition and sources in Saudi Arabia. We conducted a multi-week multiple sites sampling campaign in Jeddah between June and September, 2011, and analyzed samples by XRF. The overall mean mass concentration was 28.4 ± 25.4 μg/m 3 for PM2.5 and 87.3 ± 47.3 μg/m 3 for PM10, with significant temporal and spatial variability. The average ratio of PM2.5/PM10 was 0.33. Chemical composition data were modeled using factor analysis with varimax orthogonal rotation to determine five and four particle source categories contributing significant amount of for PM2.5 and PM10 mass, respectively. In both PM2.5 and PM10 sources were (1) heavy oil combustion characterized by high Ni and V; (2) resuspended soil characterized by high concentrations of Ca, Fe, Al, and Si; and (3) marine aerosol. The two other sources in PM2.5 were (4) Cu/Zn source; (5) traffic source identified by presence of Pb, Br, and Se; while in PM10 it was a mixed industrial source. To estimate the mass contributions of each individual source category, the CAPs mass concentration was regressed against the factor scores. Cumulatively, resuspended soil and oil combustion contributed 77 and 82% mass of PM2.5 and PM10, respectively.

Source Apportionment and Elemental Composition of PM2.5 and PM10 in Jeddah City, Saudi Arabia

PubMed Central

Khodeir, Mamdouh; Shamy, Magdy; Alghamdi, Mansour; Zhong, Mianhua; Sun, Hong; Costa, Max; Chen, Lung-Chi; Maciejczyk, Polina

2014-01-01

This paper presents the first comprehensive investigation of PM2.5 and PM10 composition and sources in Saudi Arabia. We conducted a multi-week multiple sites sampling campaign in Jeddah between June and September, 2011, and analyzed samples by XRF. The overall mean mass concentration was 28.4 ± 25.4 μg/m3 for PM2.5 and 87.3 ± 47.3 μg/m3 for PM10, with significant temporal and spatial variability. The average ratio of PM2.5/PM10 was 0.33. Chemical composition data were modeled using factor analysis with varimax orthogonal rotation to determine five and four particle source categories contributing significant amount of for PM2.5 and PM10 mass, respectively. In both PM2.5 and PM10 sources were (1) heavy oil combustion characterized by high Ni and V; (2) resuspended soil characterized by high concentrations of Ca, Fe, Al, and Si; and (3) marine aerosol. The two other sources in PM2.5 were (4) Cu/Zn source; (5) traffic source identified by presence of Pb, Br, and Se; while in PM10 it was a mixed industrial source. To estimate the mass contributions of each individual source category, the CAPs mass concentration was regressed against the factor scores. Cumulatively, resuspended soil and oil combustion contributed 77 and 82% mass of PM2.5 and PM10, respectively. PMID:24634602

Direct Radiative Effect and Heating Rate of black carbon aerosol: high time resolution measurements and source-identified forcing effects

NASA Astrophysics Data System (ADS)

Ferrero, Luca; Mocnik, Grisa; Cogliati, Sergio; Comi, Alberto; Degni, Francesca; Di Mauro, Biagio; Colombo, Roberto; Bolzacchini, Ezio

2016-04-01

Black carbon (BC) absorbs sunlight in the atmosphere heating it. However, up to now, heating rate (HR) calculations from the divergence of the net radiative flux with altitude or from the modelling activity are too sparse. This work fills the aforementioned gap presenting a new methodology based on a full set of physical equations to experimentally determine both the radiative power density absorbed into a ground-based atmospheric layer (ADRE), and the consequent HR induced by the absorptive component of aerosol. In urban context, it is essentially related to the BC. The methodology is also applicable to natural components (i.e. dust) and is obtained solving the first derivative of the main radiative transfer equations. The ADRE and the consequent HR can be determined coupling spectral aerosol absorption measurements with the spectrally resolved measurements of the direct, diffuse downward radiation and the surface reflected radiance components. Moreover, the spectral absorption of BC aerosol allows its source apportionment (traffic and biomass burning (BB)) allowing the same apportionment on HR. This work reports one year of high-time resolution measurements (5 min) of sunlight absorption and HR induced by BC aerosol over Milan. A unique sampling site was set up from March 2015 with: 1) Aethalometer (AE-31, Magee Scientific, 7-λ), 2) the Multiplexer-Radiometer-Irradiometer which detects downward and reflected radiance (350-1000 nm in 3648 spectral bands) coupled with a rotating shadow-band to measure spectrally-resolved global and diffuse radiation (thus direct), 3) a meteorological station (LSI-Lastem) equipped with 3 pyranometers (global, diffuse and refrected radiation; 300-3000 nm), a thermohygrometer, a barometer, an anemometer, 4) condensation and optical particle counters (TSI 3775 and Grimm 1.107), 5) low volume sampler (FAI Hydra dual sampler, PM2.5 and PM10) for sample collection and chemistry determination. Results concerning the radiative power density absorbed by BC and the consequent HR allowed to determine: 1) the mean monthly values along one year (i.e. October: 14.5±0.2 mW/m3, 1.04±0.01 K/day of HR, 3.0±0.1 μg/m3 of BC); 2) the importance of the direct, diffuse and reflected radiation and thus of sky conditions (clear/cloudy) on the HR (i.e. October HR: 0.42±0.10 K/day for direct, 0.44±0.10 K/day for diffuse, 0.18±0.10 K/day for reflected); 3) the daily cycle influence of BC and radiation on HR; 4) the influence of anthropogenic activity studying the daily cycle along working and non-working days (i.e. September HR: 1.00±0.06 K/day for working days, 0.35±0.02 K/day for non-working days); 5) determine the radiative effect of traffic and BB sources of BC in function of the domestic heating operation. In particular, the domestic heating is allowed in Italy starting from 15th October: traffic BC for 1-15 and 15-31 October was 1.3±0.1 μg/m3 and 2.3±0.1 μg/m3 respectively, while BB BC was 0.7±0.1 μg/m3 and 1.5±0.1 μg/m3. In terms of HR, traffic BC for 1-15 and 15-31 October contributed with 0.46±0.01 K/day and 0.74±0.02 K/day while BB BC was 0.28±0.01 K/day and 0.61±0.02 K/day. All of the aforementioned results will be detailed in the presentation using the full set of data collected.

Examining the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol formation during the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee, ground site

NASA Astrophysics Data System (ADS)

Budisulistiorini, S. H.; Li, X.; Bairai, S. T.; Renfro, J.; Liu, Y.; Liu, Y. J.; McKinney, K. A.; Martin, S. T.; McNeill, V. F.; Pye, H. O. T.; Nenes, A.; Neff, M. E.; Stone, E. A.; Mueller, S.; Knote, C.; Shaw, S. L.; Zhang, Z.; Gold, A.; Surratt, J. D.

2015-03-01

A suite of offline and real-time gas- and particle-phase measurements was deployed at Look Rock, Tennessee (TN), during the 2013 Southern Oxidant and Aerosol Study (SOAS) to examine the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formation. High- and low-time resolution PM2.5 samples were collected for analysis of known tracer compounds in isoprene-derived SOA by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) and ultra performance liquid chromatography/diode array detection-electrospray ionization-high-resolution quadrupole time-of-flight mass spectrometry (UPLC/DAD-ESI-HR-QTOFMS). Source apportionment of the organic aerosol (OA) was determined by positive matrix factorization (PMF) analysis of mass spectrometric data acquired on an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Campaign average mass concentrations of the sum of quantified isoprene-derived SOA tracers contributed to ~9% (up to 26%) of the total OA mass, with isoprene-epoxydiol (IEPOX) chemistry accounting for ~97% of the quantified tracers. PMF analysis resolved a factor with a profile similar to the IEPOX-OA factor resolved in an Atlanta study and was therefore designated IEPOX-OA. This factor was strongly correlated (r2>0.7) with 2-methyltetrols, C5-alkene triols, IEPOX-derived organosulfates, and dimers of organosulfates, confirming the role of IEPOX chemistry as the source. On average, IEPOX-derived SOA tracer mass was ~25% (up to 47%) of the IEPOX-OA factor mass, which accounted for 32% of the total OA. A low-volatility oxygenated organic aerosol (LV-OOA) and an oxidized factor with a profile similar to 91Fac observed in areas where emissions are biogenic-dominated were also resolved by PMF analysis, whereas no primary organic aerosol (POA) sources could be resolved. These findings were consistent with low levels of primary pollutants, such as nitric oxide (NO~0.03ppb), carbon monoxide (CO~116 ppb), and black carbon (BC~0.2 μg m-3). Particle-phase sulfate is fairly correlated (r2~0.3) with both MAE- and IEPOX-derived SOA tracers, and more strongly correlated (r2~0.6) with the IEPOX-OA factor, in sum suggesting an important role of sulfate in isoprene SOA formation. Moderate correlation between the methacrylic acid epoxide (MAE)-derived SOA tracer 2-methylglyceric acid with sum of reactive and reservoir nitrogen oxides (NOy; r2=0.38) and nitrate (r2=0.45) indicates the potential influence of anthropogenic emissions through long-range transport. Despite the lack of a~clear association of IEPOX-OA with locally estimated aerosol acidity and liquid water content (LWC), box model calculations of IEPOX uptake using the simpleGAMMA model, accounting for the role of acidity and aerosol water, predicted the abundance of the IEPOX-derived SOA tracers 2-methyltetrols and the corresponding sulfates with good accuracy (r2~0.5 and ~0.7, respectively). The modeling and data combined suggest an anthropogenic influence on isoprene-derived SOA formation through acid-catalyzed heterogeneous chemistry of IEPOX in the southeastern US. However, it appears that this process was not limited by aerosol acidity or LWC at Look Rock during SOAS. Future studies should further explore the extent to which acidity and LWC becomes a limiting factor of IEPOX-derived SOA, and their modulation by anthropogenic emissions.

Impacts of Combustion Conditions and Photochemical Processing on the Light Absorption of Biomass Combustion Aerosol.

PubMed

Martinsson, J; Eriksson, A C; Nielsen, I Elbæk; Malmborg, V Berg; Ahlberg, E; Andersen, C; Lindgren, R; Nyström, R; Nordin, E Z; Brune, W H; Svenningsson, B; Swietlicki, E; Boman, C; Pagels, J H

2015-12-15

The aim was to identify relationships between combustion conditions, particle characteristics, and optical properties of fresh and photochemically processed emissions from biomass combustion. The combustion conditions included nominal and high burn rate operation and individual combustion phases from a conventional wood stove. Low temperature pyrolysis upon fuel addition resulted in "tar-ball" type particles dominated by organic aerosol with an absorption Ångström exponent (AAE) of 2.5-2.7 and estimated Brown Carbon contributions of 50-70% to absorption at the climate relevant aethalometer-wavelength (520 nm). High temperature combustion during the intermediate (flaming) phase was dominated by soot agglomerates with AAE 1.0-1.2 and 85-100% of absorption at 520 nm attributed to Black Carbon. Intense photochemical processing of high burn rate flaming combustion emissions in an oxidation flow reactor led to strong formation of Secondary Organic Aerosol, with no or weak absorption. PM1 mass emission factors (mg/kg) of fresh emissions were about an order of magnitude higher for low temperature pyrolysis compared to high temperature combustion. However, emission factors describing the absorption cross section emitted per kg of fuel consumed (m(2)/kg) were of similar magnitude at 520 nm for the diverse combustion conditions investigated in this study. These results provide a link between biomass combustion conditions, emitted particle types, and their optical properties in fresh and processed plumes which can be of value for source apportionment and balanced mitigation of biomass combustion emissions from a climate and health perspective.

Numerical simulations for the sources apportionment and control strategies of PM2.5 over Pearl River Delta, China, part I: Inventory and PM2.5 sources apportionment.

PubMed

Huang, Yeqi; Deng, Tao; Li, Zhenning; Wang, Nan; Yin, Chanqin; Wang, Shiqiang; Fan, Shaojia

2018-09-01

This article uses the WRF-CMAQ model to systematically study the source apportionment of PM 2.5 under typical meteorological conditions in the dry season (November 2010) in the Pearl River Delta (PRD). According to the geographical location and the relative magnitude of pollutant emission, Guangdong Province is divided into eight subdomains for source apportionment study. The Brute-Force Method (BFM) method was implemented to simulate the contribution from different regions to the PM 2.5 pollution in the PRD. Results show that the industrial sources accounted for the largest proportion. For emission species, the total amount of NO x and VOC in Guangdong Province, and NH 3 and VOC in Hunan Province are relatively larger. In Guangdong Province, the emission of SO 2 , NO x and VOC in the PRD are relatively larger, and the NH 3 emissions are higher outside the PRD. In northerly-controlled episodes, model simulations demonstrate that local emissions are important for PM 2.5 pollution in Guangzhou and Foshan. Meanwhile, emissions from Dongguan and Huizhou (DH), and out of Guangdong Province (SW) are important contributors for PM 2.5 pollution in Guangzhou. For PM 2.5 pollution in Foshan, emissions in Guangzhou and DH are the major contributors. In addition, high contribution ratio from DH only occurs in severe pollution periods. In southerly-controlled episode, contribution from the southern PRD increases. Local emissions and emissions from Shenzhen, DH, Zhuhai-Jiangmen-Zhongshan (ZJZ) are the major contributors. Regional contribution to the chemical compositions of PM 2.5 indicates that the sources of chemical components are similar to those of PM 2.5 . In particular, SO 4 2- is mainly sourced from emissions out of Guangdong Province, while the NO 3- and NH 4+ are more linked to agricultural emissions. Copyright © 2018 Elsevier B.V. All rights reserved.

Contamination source apportionment and health risk assessment of heavy metals in soil around municipal solid waste incinerator: A case study in North China.

PubMed

Ma, Wenchao; Tai, Lingyu; Qiao, Zhi; Zhong, Lei; Wang, Zhen; Fu, Kaixuan; Chen, Guanyi

2018-08-01

Few studies have comprehensively taken into account the source apportionment and human health risk of soil heavy metals in the vicinity of municipal solid waste incinerator (MSWI) in high population density area. In this study, 8 elements (Cr, Pb, Cu, Ni, Zn, Cd, Hg, and As) in fly ash, soil samples from different functional areas and vegetables collected surrounding the MSWI in North China were determined. The single pollution index, integrated Nemerow pollution index, principal component analysis (PCA), absolute principle component score-multiple linear regression (APCS-MLR) model and dose-response model were used in this study. The results showed that the soils around the MSWI were moderately polluted by Cu, Pb, Zn, and Hg, and heavily polluted by As and Cd. MSWI had a significant influence on the distribution of soil heavy metals in different distances from MSWI. The source apportionment results showed that MSWI, natural source, industrial discharges and coal combustion were the four major potential sources for heavy metals in the soils, with the contributions of 36.08%, 29.57%, 10.07%, and 4.55%, respectively. MSWI had a major impact on Zn, Cu, Pb, Cd, and Hg contamination in soil. The non-carcinogenic risk and carcinogenic risk posed by soil heavy metals surrounding the MSWI were unacceptable. The soil heavy metals concentrations and health risks in different functional areas were distinct. MSWI was the predominate source of non-carcinogenic risk with the average contribution rate of 36.99% and carcinogenic risk to adult male, adult female and children with 4.23×10 -4 , 4.57×10 -4 , and 1.41×10 -4 respectively, implying that the impact of MSWI on human health was apparent. This study provided a new insight for the source apportionment and health risk assessment of soil heavy metals in the vicinity of MSWI. Copyright © 2018. Published by Elsevier B.V.

Temporal trend and source apportionment of water pollution in different functional zones of Qiantang River, China.

PubMed

Su, Shiliang; Li, Dan; Zhang, Qi; Xiao, Rui; Huang, Fang; Wu, Jiaping

2011-02-01

The increasingly serious river water pollution in developing countries poses great threat to environmental health and human welfare. The assignment of river function to specific uses, known as zoning, is a useful tool to reveal variations of water environmental adaptability to human impact. Therefore, characterizing the temporal trend and identifying responsible pollution sources in different functional zones could greatly improve our knowledge about human impacts on the river water environment. The aim of this study is to obtain a deeper understanding of temporal trends and sources of water pollution in different functional zones with a case study of the Qiantang River, China. Measurement data were obtained and pretreated for 13 variables from 41 monitoring sites in four categories of functional zones during the period 1996-2004. An exploratory approach, which combines smoothing and non-parametric statistical tests, was applied to characterize trends of four significant parameters (permanganate index, ammonia nitrogen, total cadmium and fluoride) accounting for differences among different functional zones identified by discriminant analysis. Aided by GIS, yearly pollution index (PI) for each monitoring site was further mapped to compare the within-group variations in temporal dynamics for different functional zones. Rotated principal component analysis and receptor model (absolute principle component score-multiple linear regression, APCS-MLR) revealed that potential pollution sources and their corresponding contributions varied among the four functional zones. Variations of APCS values for each site of one functional zone as well as their annual average values highlighted the uncertainties associated with cross space-time effects in source apportionment. All these results reinforce the notion that the concept of zoning should be taken seriously in water pollution control. Being applicable to other rivers, the framework of management-oriented source apportionment is thus believed to have potentials to offer new insights into water management and advance the source apportionment framework as an operational basis for national and local governments. © 2010 Elsevier Ltd. All rights reserved.

Countering Air and Missile Threats

DTIC Science & Technology

2012-03-23

information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources , gathering... apportionment guidance by the JFC. Functional component commands serve to ease the burden on the theater and joint task force staffs, free the JFC to focus...action (COA) to attain the desired objectives. Counterair requires a combination of OCA and DCA operations based on the JFC’s air apportionment

Source apportionment of secondary organic aerosol in China using a regional source-oriented chemical transport model and two emission inventories.

PubMed

Wang, Peng; Ying, Qi; Zhang, Hongliang; Hu, Jianlin; Lin, Yingchao; Mao, Hongjun

2018-06-01

A Community Multiscale Air Quality (CMAQ) model with source-oriented lumped SAPRC-11 (S11L) photochemical mechanism and secondary organic aerosol (SOA) module was applied to determine the contributions of anthropogenic and biogenic sources to SOA concentrations in China. A one-year simulation of 2013 using the Multi-resolution Emission Inventory for China (MEIC) shows that summer SOA are generally higher (10-15 μg m -3 ) due to large contributions of biogenic (country average 60%) and industrial sources (17%). In winter, SOA formation was mostly due to anthropogenic emissions from industries (40%) and residential sources (38%). Emissions from other countries in southeast China account for approximately 14% of the SOA in both summer and winter, and 46% in spring due to elevated open biomass burning in southeast Asia. The Regional Emission inventory in ASia v2.1 (REAS2) was applied in this study for January and August 2013. Two sets of simulations with the REAS2 inventory were conducted using two different methods to speciate total non-methane carbon into model species. One approach uses total non-methane hydrocarbon (NMHC) emissions and representative speciation profiles from the SPECIATE database. The other approach retains the REAS2 speciated species that can be directly mapped to S11L model species and uses source specific splitting factors to map other REAS2 lumped NMHC species. Biogenic emissions are still the most significant contributor in summer based on these two sets of simulations. However, contributions from the transportation sector to SOA in January are predicted to be much more important based on the two REAS2 emission inventories (∼30-40% vs. ∼5% by MEIC), and contributions from residential sources according to REAS2 was much lower (∼21-24% vs. ∼42%). These discrepancies in source contributions to SOA need to be further investigated as the country seeks for optimal emission control strategies to fight severe air pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Source apportionment of PM2.5 chemically speciated mass and particle number concentrations in New York City

NASA Astrophysics Data System (ADS)

Masiol, M.; Hopke, P. K.; Felton, H. D.; Frank, B. P.; Rattigan, O. V.; Wurth, M. J.; LaDuke, G. H.

2017-01-01

The major sources of fine particulate matter (PM2.5) in New York City (NYC) were apportioned by applying positive matrix factorization (PMF) to two different sets of particle characteristics: mass concentrations using chemical speciation data and particle number concentrations (PNC) using number size distribution, continuously monitored gases, and PM2.5 data. Post-processing was applied to the PMF results to: (i) match with meteorological data, (ii) use wind data to detect the likely locations of the local sources, and (iii) use concentration weighted trajectory models to assess the strength of potential regional/transboundary sources. Nine sources of PM2.5 mass were apportioned and identified as: secondary ammonium sulfate, secondary ammonium nitrate, road traffic exhaust, crustal dust, fresh sea-salt, aged sea-salt, biomass burning, residual oil/domestic heating and zinc. The sources of PNC were investigated using hourly average number concentrations in six size bins, gaseous air pollutants, mass concentrations of PM2.5, particulate sulfate, OC, and EC. These data were divided into 3 periods indicative of different seasonal conditions. Five sources were resolved for each period: secondary particles, road traffic, NYC background pollution (traffic and oil heating largely in Manhattan), nucleation and O3-rich aerosol. Although traffic does not account for large amounts of PM2.5 mass, it was the main source of particles advected from heavily trafficked zones. The use of residual oil had limited impacts on PM2.5 mass but dominates PNC in cold periods.

Atmospheric particulate mercury in the megacity Beijing: Spatio-temporal variations and source apportionment

NASA Astrophysics Data System (ADS)

Schleicher, N. J.; Schäfer, J.; Blanc, G.; Chen, Y.; Chai, F.; Cen, K.; Norra, S.

2015-05-01

Particulate mercury (HgP) concentrations in weekly aerosol samples (PM2.5 and TSP) from Beijing, China, were measured for a complete year. In addition, spatial differences were measured for a shorter time period at four different sites and potential source materials were analyzed. Average HgP concentrations in PM2.5 samples were 0.26 ng/m3 for day-time PM2.5, 0.28 ng/m3 for night-time PM2.5, and 0.57 ng/m3 for TSP samples, respectively. Coal combustion was identified as the major source of HgP in Beijing. Other sources included industrial activities as well as red color on historical buildings as a minor contribution. Spatial differences were pronounced with highest concentrations in the inner city (inside the 3rd ring road). The results further showed a strong seasonality with highest concentrations in winter and lowest in summer due to local meteorological conditions (precipitation in summer and stagnant conditions and low mixing layer height in winter) as well as seasonal sources, such as coal combustion for heating purposes. Day-night differences also showed a seasonal pattern with higher night-time concentrations during summer and higher day-time concentrations during winter. Compared to other cities worldwide, the HgP concentrations in Beijing were alarmingly high, suggesting that airborne particulate Hg should be the focus of future monitoring activities and mitigation measures.

The Use of Principal Component Analysis for Source Identification of PM2.5 from Selected Urban and Regional Background Sites in Poland

NASA Astrophysics Data System (ADS)

Błaszczak, Barbara

2018-01-01

The paper reports the results of the measurements of water-soluble ions and carbonaceous matter content in the fine particulate matter (PM2.5), as well as the contributions of major sources in PM2.5. Daily PM2.5 samples were collected during heating and non-heating season of the year 2013 in three different locations in Poland: Szczecin (urban background), Trzebinia (urban background) and Złoty Potok (regional background). The concentrations of PM2.5, and its related components, exhibited clear spatiotemporal variability with higher levels during the heating period. The share of the total carbon (TC) in PM2.5 exceeded 40% and was primarily determined by fluctuations in the share of OC. Sulfates (SO42-), nitrates (NO3-) and ammonium (NH4+) dominated in the ionic composition of PM2.5 and accounted together 34% (Szczecin), 30% (Trzebinia) and 18% (Złoty Potok) of PM2.5 mass. Source apportionment analysis, performed by PCA-MLRA model (Principal Component Analysis - Multilinear Regression Analysis), revealed that secondary aerosol, whose presence is related to oxidation of gaseous precursors emitted from fuel combustion and biomass burning, had the largest contribution in observed PM2.5 concentrations. In addition, the contribution of traffic sources together with road dust resuspension, was observed. The share of natural sources (sea spray, crustal dust) was generally lower.

Testing of an automated online EA-IRMS method for fast and simultaneous carbon content and stable isotope measurement of aerosol samples

NASA Astrophysics Data System (ADS)

Major, István; Gyökös, Brigitta; Túri, Marianna; Futó, István; Filep, Ágnes; Hoffer, András; Molnár, Mihály

2016-04-01

Comprehensive atmospheric studies have demonstrated that carbonaceous aerosol is one of the main components of atmospheric particulate matter over Europe. Various methods, considering optical or thermal properties, have been developed for quantification of the accurate amount of both organic and elemental carbon constituents of atmospheric aerosol. The aim of our work was to develop an alternative fast and easy method for determination of the total carbon content of individual aerosol samples collected on prebaked quartz filters whereby the mass and surface concentration becomes simply computable. We applied the conventional "elemental analyzer (EA) coupled online with an isotope ratio mass spectrometer (IRMS)" technique which is ubiquitously used in mass spectrometry. Using this technique we are able to measure simultaneously the carbon stable isotope ratio of the samples, as well. During the developing process, we compared the EA-IRMS technique with an off-line catalytic combustion method worked out previously at Hertelendi Laboratory of Environmental Studies (HEKAL). We tested the combined online total carbon content and stable isotope ratio measurement both on standard materials and real aerosol samples. Regarding the test results the novel method assures, on the one hand, at least 95% of carbon recovery yield in a broad total carbon mass range (between 100 and 3000 ug) and, on the other hand, a good reproducibility of stable isotope measurements with an uncertainty of ± 0.2 per mill. Comparing the total carbon results obtained by the EA-IRMS and the off-line catalytic combustion method we found a very good correlation (R2=0.94) that proves the applicability of both preparation method. Advantages of the novel method are the fast and simplified sample preparation steps and the fully automated, simultaneous carbon stable isotope ratio measurement processes. Furthermore stable isotope ratio results can effectively be applied in the source apportionment investigations of atmospheric carbonaceous aerosol. This research was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP 4.2.4.A/2-11-1-2012-0001 'National Excellence Program.

Source apportionment of PM2.5 for supporting control strategies in the Monterrey Metropolitan Area, Mexico.

PubMed

Martínez-Cinco, Marco; Santos-Guzmán, Jesús; Mejía-Velázquez, Gerardo

2016-06-01

The Monterrey Metropolitan Area (MMA) in Northeast Mexico has shown high PM2.5 concentrations since 2003. The data shows that the annual average concentration exceeds from 2 to 3 times the Mexican PM2.5 annual air quality standard of 12 µg/m(3). In a previous work we studied the chemical characterization of PM2.5 in two sites of the MMA during the winter season. Among the most important components we found ammonium sulfate and nitrate, elemental and organic carbon, and crustal matter. In this work we present the results of a second chemical characterization study performed during the summer time and the application of the chemical mass balance (CMB) model to determine the source apportionment of air pollutants in the region. The chemical analysis results show that the chemical composition of PM2.5 is similar in both sites and periods of the year. The results of the chemical analysis and the CMB model show that industrial, traffic, and combustion activities in the area are the major sources of primary PM2.5 and precursor gases of secondary inorganic and organic aerosol (SO2, NOx, NH3, and volatile organic compounds [VOCs]). We also found that black carbon and organic carbon are important components of PM2.5 in the MMA. These results are consistent with the MMA emission inventory that reports as major sources of particles and SO2 a refinery and fuel combustion, as well as nitrogen oxides and ammonium from transportation and industrial activities in the MMA and ammonium form agricultural activities in the state. The results of this work are important to identify and support effective actions to reduce direct emissions of PM2.5 and its precursor gases to improve air quality in the MMA. The Monterrey Metropolitan Area (MMA) has been classified as the most air-polluted area in Mexico by the World Health Organization (WHO). Effective actions need to be taken to control primary sources of PM2.5 and its precursors, reducing health risks on the population exposed and their associated costs. The results of this study identify the main sources and their estimated contribution to PM2.5 mass concentration, providing valuable information to the local environmental authorities to take decisions on PM2.5 control strategies in the MMA.

High Aerosol Concentration cases measured at Vessel Gisang 1 over the Yellow Sea during KORUS-AQ Campaign

NASA Astrophysics Data System (ADS)

Ryoo, S. B.; Yun Kyu, L.; Lee, H. C.; Cha, J. W.

2017-12-01

ADAM-Haze (Asian Dust and Haze Model) model of NIMS (National Institute of Meteorological Sciences) /KMA (Korean Meteorological Administration) was used to assess the high aerosol mass concentration cases for the cruise area using research vessel Gisang 1 over the Yellow sea during KORUS-AQ (Korea-United States Air Quality Study) campaign in 2016. In order to simplify the analysis of the route of the air mass, it is classified into five categories according to the regional characteristics of the pollution sources.(I: Around inner Mongolia and Beijing regions in China, II: Around Liaoning province in China and North Korea, III: Around South Korea and Japan, IV: Around East China sea, V: Around Shandong Peninsula and Shanghai regions in China.) using by the HYSPLIT 4 model developed by the National Oceanic and Atmospheric Administration / Air Resources Laboratory. The most frequent airborne trajectories were category V, which accounted for 32% of the total. The category I, II, and III also accounted for 19%, 21% and 26% , respectively. That means the atmospheric aerosol over the Yellow sea during the campaign was affected about 70% from China and 26% from South Korea. To clearly investigate the transport process, ADAM-Haze model separately ran for dust and non-dust cases over the Yellow sea during the cruise. For example, the model showed the Asian dust influenced the vessel observations with pollutants on May 7 2016 in I category and strong haze from Shandong peninsula in China attributed to them on May 29 2016 in V category. In addition, the comparison of the vessel observation with the model out is under study and the source apportionment will be implemented by using numerical method such as DDM (Decoupled Direct Method) calculation. Therefore, we will show you the results for the comparison and DDM calculation as well as detail results of the evaluating model performance in the conference.

Oxidative potential of ambient water-soluble PM2.5 in the southeastern United States: contrasts in sources and health associations between ascorbic acid (AA) and dithiothreitol (DTT) assays

NASA Astrophysics Data System (ADS)

Fang, Ting; Verma, Vishal; Bates, Josephine T.; Abrams, Joseph; Klein, Mitchel; Strickland, Matthew J.; Sarnat, Stefanie E.; Chang, Howard H.; Mulholland, James A.; Tolbert, Paige E.; Russell, Armistead G.; Weber, Rodney J.

2016-03-01

The ability of certain components of particulate matter to induce oxidative stress through the generation of reactive oxygen species (ROS) in vivo may be one mechanism accounting for observed linkages between ambient aerosols and adverse health outcomes. A variety of assays have been used to measure this so-called aerosol oxidative potential. We developed a semi-automated system to quantify oxidative potential of filter aqueous extracts utilizing the dithiothreitol (DTT) assay and report here the development of a similar semi-automated system for the ascorbic acid (AA) assay. Approximately 500 PM2.5 filter samples collected in contrasting locations in the southeastern US were analyzed for a host of aerosol species, along with AA and DTT activities. We present a detailed contrast in findings from these two assays. Water-soluble AA activity was higher in summer and fall than in winter, with highest levels near heavily trafficked highways, whereas DTT activity was higher in winter compared to summer and fall and more spatially homogeneous. AA activity was nearly exclusively correlated with water-soluble Cu (r = 0.70-0.94 at most sites), whereas DTT activity was correlated with organic and metal species. Source apportionment models, positive matrix factorization (PMF) and a chemical mass balance method with ensemble-averaged source impact profiles (CMB-E), suggest a strong contribution from traffic emissions and secondary processes (e.g., organic aerosol oxidation or metals mobilization by secondary acids) to both AA and DTT activities in urban Atlanta. In contrast, biomass burning was a large source for DTT activity, but insignificant for AA. AA activity was not correlated with PM2.5 mass, while DTT activity co-varied strongly with mass (r = 0.49-0.86 across sites and seasons). Various linear models were developed to estimate AA and DTT activities for the central Atlanta Jefferson Street site, based on the CMB-E sources. The models were then used to estimate daily oxidative potential at this site over the 1998-2009 period. Time series epidemiological analyses were conducted to assess daily emergency department (ED) visits data for the five-county Atlanta metropolitan area based on the estimated 10-year backcast oxidative potential. Estimated AA activity was not statistically associated with any tested health outcome, while DTT activity was associated with ED visits for both asthma or wheeze and congestive heart failure. The findings point to the importance of both organic components and transition metals from biomass burning and mobile sources to adverse health outcomes in this region.

Part 2. Development of Enhanced Statistical Methods for Assessing Health Effects Associated with an Unknown Number of Major Sources of Multiple Air Pollutants.

PubMed

Park, Eun Sug; Symanski, Elaine; Han, Daikwon; Spiegelman, Clifford

2015-06-01

A major difficulty with assessing source-specific health effects is that source-specific exposures cannot be measured directly; rather, they need to be estimated by a source-apportionment method such as multivariate receptor modeling. The uncertainty in source apportionment (uncertainty in source-specific exposure estimates and model uncertainty due to the unknown number of sources and identifiability conditions) has been largely ignored in previous studies. Also, spatial dependence of multipollutant data collected from multiple monitoring sites has not yet been incorporated into multivariate receptor modeling. The objectives of this project are (1) to develop a multipollutant approach that incorporates both sources of uncertainty in source-apportionment into the assessment of source-specific health effects and (2) to develop enhanced multivariate receptor models that can account for spatial correlations in the multipollutant data collected from multiple sites. We employed a Bayesian hierarchical modeling framework consisting of multivariate receptor models, health-effects models, and a hierarchical model on latent source contributions. For the health model, we focused on the time-series design in this project. Each combination of number of sources and identifiability conditions (additional constraints on model parameters) defines a different model. We built a set of plausible models with extensive exploratory data analyses and with information from previous studies, and then computed posterior model probability to estimate model uncertainty. Parameter estimation and model uncertainty estimation were implemented simultaneously by Markov chain Monte Carlo (MCMC*) methods. We validated the methods using simulated data. We illustrated the methods using PM2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter) speciation data and mortality data from Phoenix, Arizona, and Houston, Texas. The Phoenix data included counts of cardiovascular deaths and daily PM2.5 speciation data from 1995-1997. The Houston data included respiratory mortality data and 24-hour PM2.5 speciation data sampled every six days from a region near the Houston Ship Channel in years 2002-2005. We also developed a Bayesian spatial multivariate receptor modeling approach that, while simultaneously dealing with the unknown number of sources and identifiability conditions, incorporated spatial correlations in the multipollutant data collected from multiple sites into the estimation of source profiles and contributions based on the discrete process convolution model for multivariate spatial processes. This new modeling approach was applied to 24-hour ambient air concentrations of 17 volatile organic compounds (VOCs) measured at nine monitoring sites in Harris County, Texas, during years 2000 to 2005. Simulation results indicated that our methods were accurate in identifying the true model and estimated parameters were close to the true values. The results from our methods agreed in general with previous studies on the source apportionment of the Phoenix data in terms of estimated source profiles and contributions. However, we had a greater number of statistically insignificant findings, which was likely a natural consequence of incorporating uncertainty in the estimated source contributions into the health-effects parameter estimation. For the Houston data, a model with five sources (that seemed to be Sulfate-Rich Secondary Aerosol, Motor Vehicles, Industrial Combustion, Soil/Crustal Matter, and Sea Salt) showed the highest posterior model probability among the candidate models considered when fitted simultaneously to the PM2.5 and mortality data. There was a statistically significant positive association between respiratory mortality and same-day PM2.5 concentrations attributed to one of the sources (probably industrial combustion). The Bayesian spatial multivariate receptor modeling approach applied to the VOC data led to a highest posterior model probability for a model with five sources (that seemed to be refinery, petrochemical production, gasoline evaporation, natural gas, and vehicular exhaust) among several candidate models, with the number of sources varying between three and seven and with different identifiability conditions. Our multipollutant approach assessing source-specific health effects is more advantageous than a single-pollutant approach in that it can estimate total health effects from multiple pollutants and can also identify emission sources that are responsible for adverse health effects. Our Bayesian approach can incorporate not only uncertainty in the estimated source contributions, but also model uncertainty that has not been addressed in previous studies on assessing source-specific health effects. The new Bayesian spatial multivariate receptor modeling approach enables predictions of source contributions at unmonitored sites, minimizing exposure misclassification and providing improved exposure estimates along with their uncertainty estimates, as well as accounting for uncertainty in the number of sources and identifiability conditions.

Source apportionment of Baltimore aerosol from combined size distribution and chemical composition data

NASA Astrophysics Data System (ADS)

Ogulei, David; Hopke, Philip K.; Zhou, Liming; Patrick Pancras, J.; Nair, Narayanan; Ondov, John M.

Several multivariate data analysis methods have been applied to a combination of particle size and composition measurements made at the Baltimore Supersite. Partial least squares (PLS) was used to investigate the relationship (linearity) between number concentrations and the measured PM2.5 mass concentrations of chemical species. The data were obtained at the Ponca Street site and consisted of six days' measurements: 6, 7, 8, 18, 19 July, and 21 August 2002. The PLS analysis showed that the covariance between the data could be explained by 10 latent variables (LVs), but only the first four of these were sufficient to establish the linear relationship between the two data sets. More LVs could not make the model better. The four LVs were found to better explain the covariance between the large sized particles and the chemical species. A bilinear receptor model, PMF2, was then used to simultaneously analyze the size distribution and chemical composition data sets. The resolved sources were identified using information from number and mass contributions from each source (source profiles) as well as meteorological data. Twelve sources were identified: oil-fired power plant emissions, secondary nitrate I, local gasoline traffic, coal-fired power plant, secondary nitrate II, secondary sulfate, diesel emissions/bus maintenance, Quebec wildfire episode, nucleation, incinerator, airborne soil/road-way dust, and steel plant emissions. Local sources were mostly characterized by bi-modal number distributions. Regional sources were characterized by transport mode particles (0.2- 0.5μm).

Application of an integrated Weather Research and Forecasting (WRF)/CALPUFF modeling tool for source apportionment of atmospheric pollutants for air quality management: A case study in the urban area of Benxi, China.

PubMed

Wu, Hao; Zhang, Yan; Yu, Qi; Ma, Weichun

2018-04-01

In this study, the authors endeavored to develop an effective framework for improving local urban air quality on meso-micro scales in cities in China that are experiencing rapid urbanization. Within this framework, the integrated Weather Research and Forecasting (WRF)/CALPUFF modeling system was applied to simulate the concentration distributions of typical pollutants (particulate matter with an aerodynamic diameter <10 μm [PM 10 ], sulfur dioxide [SO 2 ], and nitrogen oxides [NO x ]) in the urban area of Benxi. Statistical analyses were performed to verify the credibility of this simulation, including the meteorological fields and concentration fields. The sources were then categorized using two different classification methods (the district-based and type-based methods), and the contributions to the pollutant concentrations from each source category were computed to provide a basis for appropriate control measures. The statistical indexes showed that CALMET had sufficient ability to predict the meteorological conditions, such as the wind fields and temperatures, which provided meteorological data for the subsequent CALPUFF run. The simulated concentrations from CALPUFF showed considerable agreement with the observed values but were generally underestimated. The spatial-temporal concentration pattern revealed that the maximum concentrations tended to appear in the urban centers and during the winter. In terms of their contributions to pollutant concentrations, the districts of Xihu, Pingshan, and Mingshan all affected the urban air quality to different degrees. According to the type-based classification, which categorized the pollution sources as belonging to the Bengang Group, large point sources, small point sources, and area sources, the source apportionment showed that the Bengang Group, the large point sources, and the area sources had considerable impacts on urban air quality. Finally, combined with the industrial characteristics, detailed control measures were proposed with which local policy makers could improve the urban air quality in Benxi. In summary, the results of this study showed that this framework has credibility for effectively improving urban air quality, based on the source apportionment of atmospheric pollutants. The authors endeavored to build up an effective framework based on the integrated WRF/CALPUFF to improve the air quality in many cities on meso-micro scales in China. Via this framework, the integrated modeling tool is accurately used to study the characteristics of meteorological fields, concentration fields, and source apportionments of pollutants in target area. The impacts of classified sources on air quality together with the industrial characteristics can provide more effective control measures for improving air quality. Through the case study, the technical framework developed in this study, particularly the source apportionment, could provide important data and technical support for policy makers to assess air pollution on the scale of a city in China or even the world.

Preliminary analysis of columnar aerosol properties in relation to surface PM measurements in the DAMOCLES 2006 field campaign (Spain)

NASA Astrophysics Data System (ADS)

Estelles, V.; Esteve, A.; Pey, J.; Martinez-Lozano, J. A.; Utrillas, M. P.; Querol, X.; de La Rosa, J.; Gonzalez-Castanedo, Y.; Alastuey, A.; Gangoiti, G.

2009-04-01

The DAMOCLES network is a Spanish thematic network, started in 2004, whose main objective is the establishment of a link among the different groups that perform research on atmospheric aerosols in Spain. Under the DAMOCLES coordination, a field campaign was held in summer 2006 at the INTA installations (El Arenosillo, Huelva) for the intercomparison of different kind of instruments devoted to in - situ and columnar aerosol measurement. During this field campaign, two daily meteorological soundings were carried out at noon and midnight for characterization of the atmospheric condition. A plane was also flown by the National Institute of Aerospace Technology (INTA) to carry airborne sensors for measuring different atmospheric factors: meteorological parameters, ozone with a 2BTech analyzer, and aerosol particle size distributions in the range (0.01-2) microns, by using a PCASP probe. The columnar aerosol properties were measured by seven CIMEL CE318 sun photometers. For in situ aerosol characterization, high volume collectors (DIGITEL and MCV) with DIGITEL for PM10, PM2.5 and PM1 measurement were used, with two cascade impactors for particulate matter measurement in 7 -8 granulometric fractions. For the PM10, PM2.5 and PM1 measurement, quartz fibre filters of 150 mm diameter were adapted. Other in situ deployed instruments were a Scanning Mobility Particle Sizer (SMPS, Model 3936), two Aerodynamic Particle Sizer (APS Model 3321) and one Grimm Spectrometer (Model #190). For characterization of the aerosol scattering at ground level, three integrating nephelometers TSI-3563 were used. For the columnar profiling we deployed five LIDAR instruments. In this study we have related the columnar aerosol measurements retrieved with one CE318 sun photometer to the surface PM measurements, mainly in some interesting situations where nearby pollution sources were influencing the local atmosphere. For the sun photometric analysis, we have applied the EuroSkyRad package (ESR.pack) to the data from the CE318 serial number #430, from the University of Valencia at Burjassot (Spain). This package is a quite new open source package composed of scripts and inversion algorithms for the processing of both Prede POM and Cimel CE318 instruments. The chemical analysis and source apportionment of the PM data was previously presented. Mean levels recorded during the campaign reached 23, 15 and 12 µg m-3 for PM10, PM2.5 and PM1, respectively. These values fell in the usual range of rural background sites of Southern Spain. Two kind of PM episodes were detected: short episodes recorded at midnight to early morning or at midday, coinciding with transitory hours when the land-sea breeze changed and stagnation conditions occurred, with pollution coming from the Huelva area; and a longer PM episode starting on 30th June 2006 and ending at the end of 1st July 2006, probably associated with the mid to long range transport of polluted air masses from Western Iberia and the Gulf of Cadiz.

Sources of ambient concentrations and chemical composition of PM 2.5-0.1 in Cork Harbour, Ireland

NASA Astrophysics Data System (ADS)

Hellebust, S.; Allanic, A.; O'Connor, I. P.; Jourdan, C.; Healy, D.; Sodeau, J. R.

2010-02-01

Particulate matter (PM 10-2.5 and PM 2.5-0.1) has been collected over a period of one year in Cork Harbour, Ireland, using a high-volume cascade impactor and polyurethane foam collection substrate. Collected PM 2.5-0.1 was analysed for water-soluble inorganic ions and metal content using ion chromatography and inductively coupled plasma-optical emission spectroscopy. On average approximately 50% by mass of the chemical content of PM was identified. The motivation for the study was to assess the potential impact of shipping emissions on air quality in Cork Harbour and City, with a view to informing public health impacts. The average ambient concentration of PM 10 between May 2007 and April 2008 was 4.6 µgm - 3 and the maximum concentration measured in one sample, representing a 4 day collection period, was 16 µgm - 3 . The major inorganic constituents identified in PM collected in Haulbowline Island in Cork Harbour were sulfate, ammonium, nitrate, chloride and sodium ions, which were mainly attributable to sea salt and secondary inorganic aerosols from regional sources. The results were analysed by principal component analysis for the purpose of source apportionment. Four factors were identified explaining over 80% of the data set variance. The factors were: shipping, sea salt, crustal material and secondary inorganic aerosols (SIA). The smaller size fraction was frequently observed to dominate, as the average concentration was 2.77 µgm - 3 for PM 2.5-0.1 compared to 1.9 µgm - 3 for PM 10-2.5. Fresh ship plumes were not found to make a significant contribution to primary PM 2.5-0.1 concentrations adjacent to the shipping channel. However, this was partially attributed to the ultrafine nature of ship emissions and the majority of the toxic metal content was attributed to emissions associated with heavy oil combustion sources, which include ship engines.

Regional evaluation of particulate matter composition in an Atlantic coastal area (Cantabria region, northern Spain): Spatial variations in different urban and rural environments

NASA Astrophysics Data System (ADS)

Arruti, A.; Fernández-Olmo, I.; Irabien, A.

2011-07-01

The aim of this study was to determine the major components (Na, Ca, K, Mg, Fe, Al, NH 4+, SO 42-, NO 3-, Cl - and TC) and trace-metal levels (As, Ni, Cd, Pb, Ti, V, Cr, Mn, Cu, Mo, Rh and Hg) in PM 10 and PM 2.5 at an Atlantic coastal city (Santander, Cantabria region, Northern Spain). Additional samples were collected in other urban sites of the Cantabria region to assess the metal content found in different urban environments within the region. To control for the mass attributed to inland regional background particulate matter, samples were also collected in Los Tojos village. The spatial variability of the major PM components shows that PM origins are different at inland and coastal sites. In the coastal city of Santander, the most important contributors are (i) the marine aerosol and (ii) the secondary inorganic aerosol (SIA) and the total carbon (TC) in PM 10 and PM 2.5, respectively. Additionally, the influence of the coastal location on the ionic balance of PM is also studied. The trace metal spatial variability is studied using the coefficient of divergence (COD), which shows that the levels of trace metals at the three studied urban sites are mainly influenced by local emission sources. The main local tracers are identified as follows: Mn in the Santander area; Mo, Cr and Pb at Reinosa; and Ni and V at Castro Urdiales. A more detailed source apportionment study of the local trace metals at Santander is conducted by Principal Component Analysis (PCA) and Positive Matrix Factorisation (PMF); these two receptor models report complementary information. From these statistical analyses, the identified sources of trace metals in PM 10 are urban background sources, industrial sources and traffic. The industrial factor was dominated by Mn, Cu and Pb, which are trace metals used in steel production and manganese-ferroalloy production plant. With respect to PM 2.5, the identified emission sources of trace metals are combustion processes as well as traffic and industrial sources.

Aliphatic and polycyclic aromatic hydrocarbons characterisation of Coimbra and Oporto PM2.5 urban aerosol

NASA Astrophysics Data System (ADS)

Rocha, A. C.; Mirante, F.; Gonçalves, C.; Nunes, T.; Alves, C.; Evtyugina, M.; Kowacz, M.; Pio, C.; Rocha, C.; Vasconcelos, T.

2009-04-01

The concentration of organic pollutants in urban areas is mostly due to incomplete combustion from vehicles, industries and domestic heating. Some of these compounds, principally the aliphatic (ALIPH) and polycyclic aromatic hydrocarbons (PAHs) promote harmful effects in human health. The determination of the ALIPH and PAHs concentration levels and their possible emission sources are useful for air quality management and source apportionment studies. In order to estimate and compare the ambient concentrations and establish the main sources of these compounds, the fine fraction of the atmospheric particulate matter (PM2.5) was collected simultaneously in Oporto and Coimbra during summer and winter seasons using a high volume sampler. The organic compounds were extracted from the particulate matter, under reflux with dichloromethane and the total organic extract (TOE) was fractionated by flash chromatography using five different eluents with increasing polarity. The hydrocarbon fractions were analysed by gas chromatography/mass spectrometry (GC/MS). Here we present and discuss the qualitative and quantitative composition of the aliphatic and aromatic fractions present in PM2.5 samples from both cities. The homologous series of C14 to C34 n-alkanes, isoprenoid hydrocarbons (pristane and phytane), PAHs and some petroleum markers have been identified and quantified. With the purpose of identifying the possible sources, various molecular diagnostic ratios were calculated. The global carbon preference index (CPI) closer to the unity, the large concentration of the unresolved complex mixture (UCM) and the presence of PAHs indicate that motor vehicle exhaust was the main emission source of the aliphatic and polycyclic aromatic fractions of Oporto and Coimbra aerosol, especially in the first city. Also, the remarkable presence of petroleum biomarkers such, as hopanes, confirms the previous results. Concentration ratios between PAHs were calculated and used to assign emission sources. The abundance and the sources of these organic pollutants for the two cities are discussed and compared taking into account the local/regional characteristics. Acknowledgement: The authors would like to thank Fundação para a Ciência e Tecnologia (FCT) for the financial support through the project POCI/AMB/60267/2004 which provided funding for the work presented here.

Source apportionment for fine particulate matter in a Chinese city using an improved gas-constrained method and comparison with multiple receptor models.

PubMed

Shi, Guoliang; Liu, Jiayuan; Wang, Haiting; Tian, Yingze; Wen, Jie; Shi, Xurong; Feng, Yinchang; Ivey, Cesunica E; Russell, Armistead G

2018-02-01

PM 2.5 is one of the most studied atmospheric pollutants due to its adverse impacts on human health and welfare and the environment. An improved model (the chemical mass balance gas constraint-Iteration: CMBGC-Iteration) is proposed and applied to identify source categories and estimate source contributions of PM 2.5. The CMBGC-Iteration model uses the ratio of gases to PM as constraints and considers the uncertainties of source profiles and receptor datasets, which is crucial information for source apportionment. To apply this model, samples of PM 2.5 were collected at Tianjin, a megacity in northern China. The ambient PM 2.5 dataset, source information, and gas-to-particle ratios (such as SO 2 /PM 2.5 , CO/PM 2.5 , and NOx/PM 2.5 ratios) were introduced into the CMBGC-Iteration to identify the potential sources and their contributions. Six source categories were identified by this model and the order based on their contributions to PM 2.5 was as follows: secondary sources (30%), crustal dust (25%), vehicle exhaust (16%), coal combustion (13%), SOC (7.6%), and cement dust (0.40%). In addition, the same dataset was also calculated by other receptor models (CMB, CMB-Iteration, CMB-GC, PMF, WALSPMF, and NCAPCA), and the results obtained were compared. Ensemble-average source impacts were calculated based on the seven source apportionment results: contributions of secondary sources (28%), crustal dust (20%), coal combustion (18%), vehicle exhaust (17%), SOC (11%), and cement dust (1.3%). The similar results of CMBGC-Iteration and ensemble method indicated that CMBGC-Iteration can produce relatively appropriate results. Copyright © 2017 Elsevier Ltd. All rights reserved.

Source apportionment and a novel approach of estimating regional contributions to ambient PM2.5 in Haikou, China.

PubMed

Liu, Baoshuang; Li, Tingkun; Yang, Jiamei; Wu, Jianhui; Wang, Jiao; Gao, Jixin; Bi, Xiaohui; Feng, Yinchang; Zhang, Yufen; Yang, Haihang

2017-04-01

A novel approach was developed to estimate regional contributions to ambient PM 2.5 in Haikou, China. In this paper, the investigation was divided into two main steps. The first step: analysing the characteristics of the chemical compositions of ambient PM 2.5 , as well as the source profiles, and then conducting source apportionments by using the CMB and CMB-Iteration models. The second step: the development of estimation approaches for regional contributions in terms of local features of Haikou and the results of source apportionment, and estimating regional contributions to ambient PM 2.5 in Haikou by this new approach. The results indicate that secondary sulphate, resuspended dust and vehicle exhaust were the major sources of ambient PM 2.5 in Haikou, contributing 9.9-21.4%, 10.1-19.0% and 10.5-20.2%, respectively. Regional contributions to ambient PM 2.5 in Haikou in spring, autumn and winter were 22.5%, 11.6% and 32.5%, respectively. The regional contribution in summer was assumed to be zero according to the better atmospheric quality and assumptions of this new estimation approach. The higher regional contribution in winter might be mainly attributable to the transport of polluted air originating in mainland China, especially from the north, where coal is burned for heating in winter. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combining emission inventory and isotope ratio analyses for quantitative source apportionment of heavy metals in agricultural soil.

PubMed

Chen, Lian; Zhou, Shenglu; Wu, Shaohua; Wang, Chunhui; Li, Baojie; Li, Yan; Wang, Junxiao

2018-08-01

Two quantitative methods (emission inventory and isotope ratio analysis) were combined to apportion source contributions of heavy metals entering agricultural soils in the Lihe River watershed (Taihu region, east China). Source apportionment based on the emission inventory method indicated that for Cd, Cr, Cu, Pb, and Zn, the mean percentage input from atmospheric deposition was highest (62-85%), followed by irrigation (12-27%) and fertilization (1-14%). Thus, the heavy metals were derived mainly from industrial activities and traffic emissions. For Ni the combined percentage input from irrigation and fertilization was approximately 20% higher than that from atmospheric deposition, indicating that Ni was mainly derived from agricultural activities. Based on isotope ratio analysis, atmospheric deposition accounted for 57-93% of Pb entering soil, with the mean value of 69.3%, which indicates that this was the major source of Pb entering soil in the study area. The mean contributions of irrigation and fertilization to Pb pollution of soil ranged from 0% to 10%, indicating that they played only a marginally important role. Overall, the results obtained using the two methods were similar. This study provides a reliable approach for source apportionment of heavy metals entering agricultural soils in the study area, and clearly have potential application for future studies in other regions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Contribution of regional-scale fire events to ozone and PM2.5 ...

EPA Pesticide Factsheets

Two specific fires from 2011 are tracked for local to regional scale contribution to ozone (O3) and fine particulate matter (PM2.5) using a freely available regulatory modeling system that includes the BlueSky wildland fire emissions tool, Spare Matrix Operator Kernel Emissions (SMOKE) model, Weather and Research Forecasting (WRF) meteorological model, and Community Multiscale Air Quality (CMAQ) photochemical grid model. The modeling system was applied to track the contribution from a wildfire (Wallow) and prescribed fire (Flint Hills) using both source sensitivity and source apportionment approaches. The model estimated fire contribution to primary and secondary pollutants are comparable using source sensitivity (brute-force zero out) and source apportionment (Integrated Source Apportionment Method) approaches. Model estimated O3 enhancement relative to CO is similar to values reported in literature indicating the modeling system captures the range of O3 inhibition possible near fires and O3 production both near the fire and downwind. O3 and peroxyacetyl nitrate (PAN) are formed in the fire plume and transported downwind along with highly reactive VOC species such as formaldehyde and acetaldehyde that are both emitted by the fire and rapidly produced in the fire plume by VOC oxidation reactions. PAN and aldehydes contribute to continued downwind O3 production. The transport and thermal decomposition of PAN to nitrogen oxides (NOX) enables O3 production in areas

Atmospheric bulk deposition to the Lagoon of Venice Part II. Source apportionment analysis near the industrial zone of Porto Marghera, Italy.

PubMed

Guerzoni, S; Rampazzo, G; Molinaroli, E; Rossini, P

2005-09-01

Multivariate statistical analyses were applied to measurements of atmospheric deposition of total particulate (TSP), inorganic elements (Al, Ca, Na, K, Mg, Si, Mn, Fe, Zn, Ni, Cr, Cu, Pb, Cd, As, Hg, V and S) and organic compounds (PAH, PCB, HCB and PCDD/F) collected in four stations, all located in the Lagoon of Venice. Aerosols at the scale of the basin (i.e., within a distance of 20 km) were mainly characterised by two end-members, one natural (composed of mineral particulate and marine spray) and one anthropogenic (with at least two different source components), affecting the sites in various ways. Variability at the two distant (>20 km) sites (Valle Dogà, Valle Figheri) was mainly due to natural components, whereas the other two stations (city of Venice, Dogaletto, approximately 5 km) were mainly impacted by industrial (and urban) sources. Total annual inputs were compared with the limits recently set by law (maximum allowed discharge=MAD). In the year of study, MAD values were exceeded for total As, Cd, Hg, Pb, dissolved Zn, PAH and PCDD/F. These results indicate that industrial sources gave rise to a quasi-permanent compositional (background) effect near the industrial area. The risk associated with atmospheric deposition should be quantified within the DSPIR framework to avoid future negative consequences in populations living in the vicinity of Porto Marghera.

Detection of Saharan dust and biomass burning events using near-real-time intensive aerosol optical properties in the north-western Mediterranean

NASA Astrophysics Data System (ADS)

Ealo, Marina; Alastuey, Andrés; Ripoll, Anna; Pérez, Noemí; Cruz Minguillón, María; Querol, Xavier; Pandolfi, Marco

2016-10-01

The study of Saharan dust events (SDEs) and biomass burning (BB) emissions are both topics of great scientific interest since they are frequent and important polluting scenarios affecting air quality and climate. The main aim of this work is evaluating the feasibility of using near-real-time in situ aerosol optical measurements for the detection of these atmospheric events in the western Mediterranean Basin (WMB). With this aim, intensive aerosol optical properties (SAE: scattering Ångström exponent, AAE: absorption Ångström exponent, SSAAE: single scattering albedo Ångström exponent and g: asymmetry parameter) were derived from multi-wavelength aerosol light scattering, hemispheric backscattering and absorption measurements performed at regional (Montseny; MSY, 720 m a.s.l.) and continental (Montsec; MSA, 1570 m a.s.l.) background sites in the WMB. A sensitivity study aiming at calibrating the measured intensive optical properties for SDEs and BB detection is presented and discussed. The detection of SDEs by means of the SSAAE parameter and Ångström matrix (made up by SAE and AAE) depended on the altitude of the measurement station and on SDE intensity. At MSA (mountain-top site) SSAAE detected around 85 % of SDEs compared with 50 % at the MSY station, where pollution episodes dominated by fine anthropogenic particles frequently masked the effect of mineral dust on optical properties during less intense SDEs. Furthermore, an interesting feature of SSAAE was its capability to detect the presence of mineral dust after the end of SDEs. Thus, resuspension processes driven by summer regional atmospheric circulations and dry conditions after SDEs favoured the accumulation of mineral dust at regional level having important consequences for air quality. On average, SAE, AAE and g ranged between -0.7 and 1, 1.3 and 2.5 and 0.5 and 0.75 respectively during SDEs. Based on the aethalometer model, BB contribution to equivalent black carbon (BC) accounted for 36 and 40 % at MSY and MSA respectively. Linear relationships were found between AAE and %BCbb, with AAE values reaching around 1.5 when %BCbb was higher than 50 %. BB contribution to organic matter (OM) at MSY was around 30 %. Thus fossil fuel (FF) combustion sources showed important contributions to both BC and OM in the region under study. Results for OM source apportionment showed good agreement with simultaneous biomass burning organic aerosol (BBOA) and hydrocarbon-like organic aerosol (HOA) obtained by applying a positive matrix factorization model (PMF) to simultaneous Aerosol Chemical Speciation Monitor (ACSM) measurements. A wildfire episode was identified at MSY, showing AAE values up to 2 when daily BB contributions to BC and OM were 73 and 78 % respectively.

Implementation and evaluation of PM2.5 source contribution analysis in a photochemical model

EPA Science Inventory

Source culpability assessments are useful for developing effective emissions control programs. The Integrated Source Apportionment Method (ISAM) has been implemented in the Community Multiscale Air Quality (CMAQ) model to track contributions from source groups and regions to ambi...

Source Region Identification Using Kernel Smoothing

EPA Science Inventory

As described in this paper, Nonparametric Wind Regression is a source-to-receptor source apportionment model that can be used to identify and quantify the impact of possible source regions of pollutants as defined by wind direction sectors. It is described in detail with an exam...

Radiocarbon-insights into temporal variations in the sources and concentrations of carbonaceous aerosols in the Los Angeles and Salt Lake City Metropolitan Areas

NASA Astrophysics Data System (ADS)

Czimczik, Claudia; Mouteva, Gergana; Simon, Fahrni; Guaciara, Santos; James, Randerson

2014-05-01

Increased fossil fuel consumption and biomass burning are contributing to significantly larger emissions of black carbon (BC) aerosols to the atmosphere. Together with organic carbon (OC), BC is a major constituent of fine particulate matter in urban air, contributes to haze and has been linked to a broad array of adverse health effects. Black carbon's high light absorption capacity and role in key (in-)direct climate feedbacks also lead to a range of impacts in the Earth system (e.g. warming, accelerated snow melt, changes in cloud formation). Recent work suggests that regulating BC emissions can play an important role in improving regional air quality and reducing future climate warming. However, BC's atmospheric transport pathways, lifetime and magnitudes of emissions by sector and region, particularly emissions from large urban centers, remain poorly constrained by measurements. Contributions of fossil and modern sources to the carbonaceous aerosol pool (corresponding mainly to traffic/industrial and biomass-burning/biogenic sources, respectively) can be quantified unambiguously by measuring the aerosol radiocarbon (14C) content. However, accurate 14C-based source apportionment requires the physical isolation of BC and OC, and minimal sample contamination with extraneous carbon or from OC charring. Compound class-specific 14C analysis of BC remains challenging due to very small sample sizes (5-15 ug C). Therefore, most studies to date have only analyzed the 14C content of the total organic carbonaceous aerosol fraction. Here, we present time-series 14C data of BC and OC from the Los Angeles (LA) metropolitan area in California - one of two megacities in the United States - and from Salt Lake City (SLC), UT. In the LA area, we analyzed 48h-PM10 samples near the LA port throughout 2007 and 2008 (with the exception of summer). We also collected monthly-PM2.5 samples at the University of California - Irvine, with shorter sampling periods during regional wildfire activity and Santa Ana winds from March to August 2013. In SLC, we seasonally collected 48h-PM2.5 samples from October 2012 to February 2014. We isolated and quantified BC and OC using a thermo-optical analyzer (RT 3080, Sunset Laboratory, Tigard, OR, USA) with the Swiss_4S protocol, and measured the 14C content of BC and OC with accelerator mass spectrometry at UCI's KCCAMS facility. We also measured the concentration and stable isotope composition of total (organic) carbon and nitrogen on the aerosol filters with EA-IRMS (Carlo Erba coupled to Finnigan DeltaPlus). Preliminary results suggest that in LA, PM10-BC concentrations are on the order of 2-8 ug C/m3. Black carbon is 14C-depleted (FM 0.04-0.21) - indicating that fossil sources dominate emissions. In comparison, OC concentrations were higher (12-17 ugC/m3) and more enriched in 14C (FM 0.54-0.83). In SLC, PM2.5-BC concentrations range from <1 to 3 ug C/m3, with the highest concentrations observed during wintertime inversions. The BC fraction is strongly 14C -depleted (FM 0.06 to 0.12) - indicating a dominance of fossil BC emissions throughout the year. Together, our measurements contribute to a comprehensive quantification of temporal and spatial variations in urban BC, a key uncertainty in constraining BC sources and transport in western North America.

Temporal-spatial characteristics and source apportionment of PM2.5 as well as its associated chemical species in the Beijing-Tianjin-Hebei region of China.

PubMed

Gao, Jiajia; Wang, Kun; Wang, Yong; Liu, Shuhan; Zhu, Chuanyong; Hao, Jiming; Liu, Huanjia; Hua, Shenbing; Tian, Hezhong

2018-02-01

PM 2.5 and its major chemical compositions were sampled and analyzed in January, April, July and October of 2014 at Beijing (BJ), Tianjin (TJ), Langfang (LF) and Baoding (BD) in order to probe the temporal and spatial characteristics as well as source apportionment of PM 2.5 in the Beijing-Tianjin-Hebei (BTH) region. The results showed that PM 2.5 pollution was severe in the BTH region. The average annual concentrations of PM 2.5 at four sampling sites were in the range of 126-180 μg/m 3 , with more than 95% of sampling days exceeding 35 μg/m 3 , the limit ceiling of average annual concentration of PM 2.5 regulated in the Chinese National Ambient Air Quality Standards (GB3095-2012). Additionally, concentrations of PM 2.5 and its major chemical species were seasonally dependent and demonstrated spatially similar variation characteristics in the BTH region. Concentration of toxic heavy metals, such as As, Cd, Cr, Cu, Mn, Ni, Pb, Sb, Se, and Zn, were higher in winter and autumn. Secondary inorganic ions (SO 4 2- , NO 3 - , and NH 4 + ) were the three-major water-soluble inorganic ions (WSIIs) of PM 2.5 and their mass ratios to PM 2.5 were higher in summer and autumn. The organic carbon (OC) and elemental carbon (EC) concentrations were lower in spring and summer than in autumn and winter. Five factors were selected in Positive Matrix Factorization (PMF) model analysis, and the results showed that PM 2.5 pollution was dominated by vehicle emissions in Beijing, combustion emissions including coal burning and biomass combustion in Langfang and Baoding, and soil and construction dust emissions in Tianjin, respectively. The air mass that were derived from the south and southeast local areas around BTH regions reflected the features of short-distant and small-scale air transport. Shandong, Henan, and Hebei were identified the major potential sources-areas of secondary aerosol emissions to PM 2.5 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Introductory lecture: atmospheric organic aerosols: insights from the combination of measurements and chemical transport models.

PubMed

Pandis, Spyros N; Donahue, Neil M; Murphy, Benjamin N; Riipinen, Ilona; Fountoukis, Christos; Karnezi, Eleni; Patoulias, David; Skyllakou, Ksakousti

2013-01-01

The formation, atmospheric evolution, properties, and removal of organic particulate matter remain some of the least understood aspects of atmospheric chemistry despite the importance of organic aerosol (OA) for both human health and climate change. Here, we summarize our recent efforts to deal with the chemical complexity of the tens of thousands of organic compounds in the atmosphere using the volatility-oxygen content framework (often called the 2D-Volatility Basis Set, 2D-VBS). Our current ability to measure the ambient OA concentration as a function of its volatility and oxygen to carbon (O:C) ratio is evaluated. The combination of a thermodenuder, isothermal dilution and Aerosol Mass Spectrometry (AMS) together with a mathematical aerosol dynamics model is a promising approach. The development of computational modules based on the 2D-VBS that can be used in chemical transport models (CTMs) is described. Approaches of different complexity are tested against ambient observations, showing the challenge of simulating the complex chemical evolution of atmospheric OA. The results of the simplest approach describing the net change due to functionalization and fragmentation are quite encouraging, reproducing both the observed OA levels and O : C in a variety of conditions. The same CTM coupled with source-apportionment algorithms can be used to gain insights into the travel distances and age of atmospheric OA. We estimate that the average age of OA near the ground in continental locations is 1-2 days and most of it was emitted (either as precursor vapors or particles) hundreds of kilometers away. Condensation of organic vapors on fresh particles is critical for the growth of these new particles to larger sizes and eventually to cloud condensation nuclei (CCN) sizes. The semivolatile organics currently simulated by CTMs are too volatile to condense on these tiny particles with high curvature. We show that chemical aging reactions converting these semivolatile compounds to extremely low volatility compounds can explain the observed growth rates of new particles in rural environments.

Winter-time size distribution and source apportionment of total suspended particulate matter and associated metals in Delhi

NASA Astrophysics Data System (ADS)

Srivastava, Arun; Gupta, Sandeep; Jain, V. K.

2009-03-01

A study of the winter time size distribution and source apportionment of total suspended particulate matter (TSPM) and associated heavy metal concentrations have been carried out for the city of Delhi. This study is important from the point of view of implementation of compressed natural gas (CNG) as alternate of diesel fuel in the public transport system in 2001 to reduce the pollution level. TSPM were collected using a five-stage cascade impactor at six sites in the winters of 2005-06. The results of size distribution indicate that a major portion (~ 40%) of TSPM concentration is in the form of PM0.7 (< 0.7 μm). Similar trends were observed with most of the heavy metals associated with various size fractions of TSPM. A very good correlation between coarse and fine size fraction of TSPM was observed. It was also observed that the metals associated with coarse particles have more chances of correlation with other metals; rather they are associated with fine particles. Source apportionment was carried out separately in coarse and fine size modes of TSPM by Chemical Mass Balance Receptor Model (CMB8) as well as by Principle Component Analysis (PCA) of SPSS. Source apportionment by PCA reveals that there are two major sources (possibly vehicular and crustal re-suspension) in both coarse and fine size fractions. Results obtained by CMB8 show the dominance of vehicular pollutants and crustal dust in fine and coarse size mode respectively. Noticeably the dominance of vehicular pollutants are now confined to fine size only whilst during pre CNG era it dominated both coarse and fine size mode. An increase of 42.5, 44.4, 48.2, 38.6 and 38.9% in the concentrations of TSPM, PM10.9, coarse particles, fine particles and lead respectively was observed during pre (2001) to post CNG (2005-06) period.

Laboratory and field measurements of organic aerosols with the photoionization aerosol mass spectrometer

NASA Astrophysics Data System (ADS)

Dreyfus, Matthew A.

Analytical methods developed to sample and characterize ambient organic aerosols often face the trade-off between long sampling times and the loss of detailed information regarding specific chemical species present. The soft, universal ionization scheme of the Photoionization Aerosol Mass Spectrometer (PIAMS) allows for identification of various chemical compounds by a signature ion, often the molecular ion. The goal of this thesis work is to apply PIAMS to both laboratory and field experiments to answer questions regarding the formation, composition, and behavior of organic aerosols. To achieve this goal, a variety of hardware and software upgrades were administered to PIAMS to optimize the instrument. Data collection and processing software were either refined or built from the ground up to simplify difficult or monotonous tasks. Additional components were added to PIAMS with the intent to automate the instrument, enhance the results, and make the instrument more rugged and user-friendly. These changes, combined with the application of an external particle concentration system (mini-Versatile Aerosol Concentration Enrichment System, m-VACES), allowed PIAMS to be suitable for field measurements of organic aerosols. Two such field campaigns were completed, both at the State of Delaware Air Quality Monitoring Site in Wilmington, Delaware: a one week period in June, 2006, and an 18 day period in October and November of 2007. A sampling method developed was capable of collecting sufficient ambient organic aerosol and analyzing it with a time resolution of 3.5 minutes. Because of this method, short term concentration changes of individual species can be tracked. Combined with meteorological data, the behavior of these species can be analyzed as a function of time or wind direction. Many compounds are found at enhanced levels during the evening/night-time hours; potentially due to the combined effects of temperature inversion, and fresh emissions in a cooler environment. The high-time resolution data shows that rapid concentration changes of a common individual species can be lost with traditional bulk sampling, and a time resolution of 30 minutes is suggested to accurately represent these changes. Using the mass spectra collected from the extended sampling campaign, source apportionment was performed with positive matrix factorization (PMF). The resulting model features six factors either correlated to specific sources (meat cooking, car emissions/road dust, diesel exhaust) or types of compounds (phthalates, alkanes/alkanoic acids, PAHs). The high-time resolution data allowed for the observation of specific trends in each factor's behavior as a function of time and wind direction relative to the receptor site. Elemental carbon/organic carbon (EC/OC) data is used to calculate the percentages of primary and secondary organic aerosol. Primary organic aerosol (POA) constituted the vast majority of the total carbon at 91% (an average of 2.8 +/- 1.1mug/m 3); 30% of which came from combustion, and 70% from non-combustion sources. These results can be explained by the PIAMS data: the diesel factor contributes to the combustion-related POA; the car/road dust, meat cooking, and alkane/alkanoic acid factors contribute the majority of non-combustion POA. The remaining factors represent <5% of the remaining OC. Considering the compatibility of data from the EC/OC and PIAMS, the ability of PIAMS to yield molecular species information to further define the primary and secondary organic aerosol factions is a distinct advantage in describing the behavior of the Wilmington organic aerosol. PIAMS was also applied to laboratory experiments. These experiments simulated complex environmental processes in order to focus on answering a central question. By mixing cholesterol aerosol with ozone in a smog chamber, and monitoring the concentration of cholesterol with PIAMS, the rate of reaction was determined. This rate indicates that cholesterol aerosol, which is a suggested source tracer, will remain in the ambient air for a few days under normal conditions. PIAMS was also used to assist in identifying products from the ozonolysis of various monoterpenes. The product ion peaks observed indicates that both the stabilized Criegee intermediate pathway and the hydroperoxide channel are both active pathways in yielding dimers and high-order oligomer.

Spatial variability of trace elements and sources for improved exposure assessment in Barcelona

NASA Astrophysics Data System (ADS)

Minguillón, María Cruz; Cirach, Marta; Hoek, Gerard; Brunekreef, Bert; Tsai, Ming; de Hoogh, Kees; Jedynska, Aleksandra; Kooter, Ingeborg M.; Nieuwenhuijsen, Mark; Querol, Xavier

2014-06-01

Trace and major elements concentrations in PM10 and PM2.5 were measured at 20 sites spread in the Barcelona metropolitan area (1 rural background, 6 urban background, 13 road traffic sites) and at 1 reference site. Three 2-week samples per site and size fraction were collected during 2009 using low volume samplers, adding a total of 120 samples. Collected samples were analysed for elemental composition using Energy Dispersive X-ray fluorescence (XRF). EC, OC, and hopanes and steranes concentrations in PM2.5 were determined. Positive Matrix Factorisation (PMF) model was used for a source apportionment analysis. The work was performed as part of the ESCAPE project. Elements were found in concentrations within the usual range in Spanish urban areas. Mineral elements were measured in higher concentrations during the warm season, due to enhanced resuspension; concentrations of fueloil combustion elements were also higher in summer. Elements in higher concentration at the traffic sites were: Ba, Cr, Cu, Fe, Mn, Mo, Pb, Sn, Zn and Zr. Spatial variations related to non-traffic sources were observed for concentrations of Br, Cl, K, and Na (sea salt origin) and Ni, V and S (shipping emissions), which were higher at the coastal sites, as well as for Zn and Pb, higher at sites closer to industrial facilities. Five common sources for PM10 and PM2.5 were identified by PMF: road traffic (with tracers Ba, Cr, Cu, Fe, Mo and Zn); fueloil combustion (Ni and V); secondary sulphate; industry (Pb and Zn); and mineral source (Al, Ca, Mg, Si, Sr and Ti). A marine aerosol source, a mixture of sea salt with aged anthropogenic aerosols, was found only in PM10. EC, hopanes and steranes concentrations correlate strongly with the PM10 road traffic source contributions, being hence all attributed to the same source. OC may arise from other sources in addition to road traffic and have a high contribution of secondary OC. Significant spatial and temporal variation in the PM2.5 and PM10 elemental composition was found. Spatial patterns differed per element, related to the main source. The identified source contributions can be used in health studies of source-specific particles.

Carbonaceous aerosols emitted from light-duty vehicles operating on gasoline and ethanol fuel blends.

PubMed

Hays, Michael D; Preston, William; George, Barbara J; Schmid, Judy; Baldauf, Richard; Snow, Richard; Robinson, James R; Long, Thomas; Faircloth, James

2013-12-17

This study examines the chemical properties of carbonaceous aerosols emitted from three light-duty gasoline vehicles (LDVs) operating on gasoline (e0) and ethanol-gasoline fuel blends (e10 and e85). Vehicle road load simulations were performed on a chassis dynamometer using the three-phase LA-92 unified driving cycle (UDC). Effects of LDV operating conditions and ambient temperature (-7 and 24 °C) on particle-phase semivolatile organic compounds (SVOCs) and organic and elemental carbon (OC and EC) emissions were investigated. SVOC concentrations and OC and EC fractions were determined with thermal extraction-gas chromatography-mass spectrometry (TE-GC-MS) and thermal-optical analysis (TOA), respectively. LDV aerosol emissions were predominantly carbonaceous, and EC/PM (w/w) decreased linearly with increasing fuel ethanol content. TE-GC-MS analysis accounted for up to 4% of the fine particle (PM2.5) mass, showing the UDC phase-integrated sum of identified SVOC emissions ranging from 0.703 μg km(-1) to 18.8 μg km(-1). Generally, higher SVOC emissions were associated with low temperature (-7 °C) and engine ignition; mixed regression models suggest these emissions rate differences are significant. Use of e85 significantly reduced the emissions of lower molecular weight PAH. However, a reduction in higher molecular weight PAH entities in PM was not observed. Individual SVOC emissions from the Tier 2 LDVs and fuel technologies tested are substantially lower and distributed differently than those values populating the United States emissions inventories currently. Hence, this study is likely to influence future apportionment, climate, and air quality model predictions that rely on source combustion measurements of SVOCs in PM.

O3 Source Contribution During a Heavy O3 Pollution Episode in Shanghai China

EPA Science Inventory

Source culpability assessments are useful for developing effective emission control strategies. The Integrated Source Apportionment Method (ISAM) has been implemented in CMAQ to track contributions from source groups and regions to ambient levels and deposited amounts of O3. CMAQ...

Sensitivity tests to define the source apportionment performance criteria in the DeltaSA tool

NASA Astrophysics Data System (ADS)

Pernigotti, Denise; Belis, Claudio A.

2017-04-01

Identification and quantification of the contribution of emission sources to a given area is a key task for the design of abatement strategies. Moreover, European member states are obliged to report this kind of information for zones where the pollution levels exceed the limit values. At present, little is known about the performance and uncertainty of the variety of methodologies used for source apportionment and the comparability between the results of studies using different approaches. The source apportionment Delta (SA Delta) is a tool developed by the EC-JRC to support the particulate matter source apportionment modellers in the identification of sources (for factor analysis studies) and/or in the measure of their performance. The source identification is performed by the tool measuring the proximity of any user chemical profile to preloaded repository data (SPECIATE and SPECIEUROPE). The model performances criteria are based on standard statistical indexes calculated by comparing participants' source contribute estimates and their time series with preloaded references data. Those preloaded data refer to previous European SA intercomparison exercises: the first with real world data (22 participants), the second with synthetic data (25 participants) and the last with real world data which was also extended to Chemical Transport Models (38 receptor models and 4 CTMs). The references used for the model performances are 'true' (predefined by JRC) for the synthetic while they are calculated as ensemble average of the participants' results in real world intercomparisons. The candidates used for each source ensemble reference calculation were selected among participants results based on a number of consistency checks plus the similarity between their chemical profiles to the repository measured data. The estimation of the ensemble reference uncertainty is crucial in order to evaluate the users' performances against it. For this reason a sensitivity analysis on different methods to estimate the ensemble references' uncertainties was performed re-analyzing the synthetic intercomparison dataset, the only one where 'true' reference and ensemble reference contributions were both present. The Delta SA is now available on-line and will be presented, with a critical discussion of the sensitivity analysis on the ensemble reference uncertainty. In particular the grade of among participants mutual agreement on the presence of a certain source should be taken into account. Moreover also the importance of the synthetic intercomparisons in order to catch receptor models common biases will be stressed.

Sources and atmospheric processing of size segregated aerosol particles revealed by stable carbon isotope ratios and chemical speciation.

PubMed

Masalaite, A; Holzinger, R; Ceburnis, D; Remeikis, V; Ulevičius, V; Röckmann, T; Dusek, U

2018-05-07

Size-segregated aerosol particles were collected during winter sampling campaigns at a coastal (55°37' N, 21°03'E) and an urban (54°64' N, 25°18' E) site. Organic compounds were thermally desorbed from the samples at different temperature steps ranging from 100 °C to 350 °C. The organic matter (OM) desorbed at each temperature step is analysed for stable carbon isotopes using an isotope ratio mass spectrometer (IRMS) and for individual organic compounds using a Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-MS). The OM desorbed at temperatures <200 °C was classified as less refractory carbon and the OM desorbed at temperatures between 200 °C and 350 °C was classified as more refractory carbon. At the coastal site, we identified two distinct time periods. The first period was more frequently influenced by marine air masses than the second time period, which was characterized by Easterly wind directions and continental air masses. During the first period OM contained a large fraction of hydrocarbons and had a carbon isotopic signature typical of liquid fossil fuels in the region. Organic mass spectra provide strong evidence that shipping emissions are a significant source of OM at this coastal site. The isotopic and chemical composition of OM during the second period at the coastal site was similar to the composition at the urban site. There was a clear distinction in source contribution between the less refractory OM and the more refractory OM at these sites. According to the source apportionment method used in this study, we were able to identify fossil fuel burning as predominant source of the less refractory OM in the smallest particles (D 50  < 0.18 μm), and biomass burning as predominant source of the more refractory OM in the larger size range (0.32 < D 50  < 1 μm). Copyright © 2018 Elsevier Ltd. All rights reserved.

SPECIATE--EPA'S DATABASE OF SPECIATED EMISSION PROFILES

EPA Science Inventory

SPECIATE is EPA's repository of Total Organic Compound and Particulate Matter speciated profiles for a wide variety of sources. The profiles in this system are provided for air quality dispersion modeling and as a library for source-receptor and source apportionment type models. ...

RECENT APPLICATIONS OF SOURCE APPORTIONMENT METHODS AND RELATED NEEDS

EPA Science Inventory

Traditional receptor modeling studies have utilized factor analysis (like principal component analysis, PCA) and/or Chemical Mass Balance (CMB) to assess source influences. The limitations with these approaches is that PCA is qualitative and CMB requires the input of source pr...

"OZONE SOURCE APPORTIONMENT IN CMAQ'

EPA Science Inventory

Ozone source attribution has been used to support various policy purposes including interstate transport (Cross State Air Pollution Rule) by U.S. EPA and ozone nonattainment area designations by State agencies. Common scientific applications include tracking intercontinental tran...

Source apportionment of heavy metals in agricultural soil based on PMF: A case study in Hexi Corridor, northwest China.

PubMed

Guan, Qingyu; Wang, Feifei; Xu, Chuanqi; Pan, Ninghui; Lin, Jinkuo; Zhao, Rui; Yang, Yanyan; Luo, Haiping

2018-02-01

Hexi Corridor is the most important base of commodity grain and producing area for cash crops. However, the rapid development of agriculture and industry has inevitably led to heavy metal contamination in the soils. Multivariate statistical analysis, GIS-based geostatistical methods and Positive Matrix Factorization (PMF) receptor modeling techniques were used to understand the levels of heavy metals and their source apportionment for agricultural soil in Hexi Corridor. The results showed that the average concentrations of Cr, Cu, Ni, Pb and Zn were lower than the secondary standard of soil environmental quality; however, the concentrations of eight metals (Cr, Cu, Mn, Ni, Pb, Ti, V and Zn) were higher than background values, and their corresponding enrichment factor values were significantly greater than 1. Different degrees of heavy metal pollution occurred in the agricultural soils; specifically, Ni had the most potential for impacting human health. The results from the multivariate statistical analysis and GIS-based geostatistical methods indicated both natural sources (Co and W) and anthropogenic sources (Cr, Cu, Mn, Ni, Pb, Ti, V and Zn). To better identify pollution sources of heavy metals in the agricultural soils, the PMF model was applied. Further source apportionment revealed that enrichments of Pb and Zn were attributed to traffic sources; Cr and Ni were closely related to industrial activities, including mining, smelting, coal combustion, iron and steel production and metal processing; Zn and Cu originated from agricultural activities; and V, Ti and Mn were derived from oil- and coal-related activities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advanced source apportionment of size-resolved trace elements at multiple sites in London during winter

DOE PAGES

Visser, S.; Slowik, Jay G.; Furger, M.; ...

2015-10-12

Here, trace element measurements in PM 10–2.5, PM 2.5–1.0 and PM 1.0–0.3 aerosol were performed with 2 h time resolution at kerbside, urban background and rural sites during the ClearfLo winter 2012 campaign in London. The environment-dependent variability of emissions was characterized using the Multilinear Engine implementation of the positive matrix factorization model, conducted on data sets comprising all three sites but segregated by size. Combining the sites enabled separation of sources with high temporal covariance but significant spatial variability. Separation of sizes improved source resolution by preventing sources occurring in only a single size fraction from having too smallmore » a contribution for the model to resolve. Anchor profiles were retrieved internally by analysing data subsets, and these profiles were used in the analyses of the complete data sets of all sites for enhanced source apportionment. A total of nine different factors were resolved (notable elements in brackets): in PM 10–2.5, brake wear (Cu, Zr, Sb, Ba), other traffic-related (Fe), resuspended dust (Si, Ca), sea/road salt (Cl), aged sea salt (Na, Mg) and industrial (Cr, Ni); in PM 2.5–1.0, brake wear, other traffic-related, resuspended dust, sea/road salt, aged sea salt and S-rich (S); and in PM 1.0–0.3, traffic-related (Fe, Cu, Zr, Sb, Ba), resuspended dust, sea/road salt, aged sea salt, reacted Cl (Cl), S-rich and solid fuel (K, Pb). Human activities enhance the kerb-to-rural concentration gradients of coarse aged sea salt, typically considered to have a natural source, by 1.7–2.2. These site-dependent concentration differences reflect the effect of local resuspension processes in London. The anthropogenically influenced factors traffic (brake wear and other traffic-related processes), dust and sea/road salt provide further kerb-to-rural concentration enhancements by direct source emissions by a factor of 3.5–12.7. The traffic and dust factors are mainly emitted in PM 10–2.5 and show strong diurnal variations with concentrations up to 4 times higher during rush hour than during night-time. Regionally influenced S-rich and solid fuel factors, occurring primarily in PM 1.0–0.3, have negligible resuspension influences, and concentrations are similar throughout the day and across the regions.« less

Advanced source apportionment of size-resolved trace elements at multiple sites in London during winter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Visser, S.; Slowik, Jay G.; Furger, M.

Here, trace element measurements in PM 10–2.5, PM 2.5–1.0 and PM 1.0–0.3 aerosol were performed with 2 h time resolution at kerbside, urban background and rural sites during the ClearfLo winter 2012 campaign in London. The environment-dependent variability of emissions was characterized using the Multilinear Engine implementation of the positive matrix factorization model, conducted on data sets comprising all three sites but segregated by size. Combining the sites enabled separation of sources with high temporal covariance but significant spatial variability. Separation of sizes improved source resolution by preventing sources occurring in only a single size fraction from having too smallmore » a contribution for the model to resolve. Anchor profiles were retrieved internally by analysing data subsets, and these profiles were used in the analyses of the complete data sets of all sites for enhanced source apportionment. A total of nine different factors were resolved (notable elements in brackets): in PM 10–2.5, brake wear (Cu, Zr, Sb, Ba), other traffic-related (Fe), resuspended dust (Si, Ca), sea/road salt (Cl), aged sea salt (Na, Mg) and industrial (Cr, Ni); in PM 2.5–1.0, brake wear, other traffic-related, resuspended dust, sea/road salt, aged sea salt and S-rich (S); and in PM 1.0–0.3, traffic-related (Fe, Cu, Zr, Sb, Ba), resuspended dust, sea/road salt, aged sea salt, reacted Cl (Cl), S-rich and solid fuel (K, Pb). Human activities enhance the kerb-to-rural concentration gradients of coarse aged sea salt, typically considered to have a natural source, by 1.7–2.2. These site-dependent concentration differences reflect the effect of local resuspension processes in London. The anthropogenically influenced factors traffic (brake wear and other traffic-related processes), dust and sea/road salt provide further kerb-to-rural concentration enhancements by direct source emissions by a factor of 3.5–12.7. The traffic and dust factors are mainly emitted in PM 10–2.5 and show strong diurnal variations with concentrations up to 4 times higher during rush hour than during night-time. Regionally influenced S-rich and solid fuel factors, occurring primarily in PM 1.0–0.3, have negligible resuspension influences, and concentrations are similar throughout the day and across the regions.« less

Contamination characteristics and source apportionment of trace metals in soils around Miyun Reservoir.

PubMed

Chen, Haiyang; Teng, Yanguo; Chen, Ruihui; Li, Jiao; Wang, Jinsheng

2016-08-01

Due to their toxicity and bioaccumulation, trace metals in soils can result in a wide range of toxic effects on animals, plants, microbes, and even humans. Recognizing the contamination characteristics of soil metals and especially apportioning their potential sources are the necessary preconditions for pollution prevention and control. Over the past decades, several receptor models have been developed for source apportionment. Among them, positive matrix factorization (PMF) has gained popularity and was recommended by the US Environmental Protection Agency as a general modeling tool. In this study, an extended chemometrics model, multivariate curve resolution-alternating least squares based on maximum likelihood principal component analysis (MCR-ALS/MLPCA), was proposed for source apportionment of soil metals and applied to identify the potential sources of trace metals in soils around Miyun Reservoir. Similar to PMF, the MCR-ALS/MLPCA model can incorporate measurement error information and non-negativity constraints in its calculation procedures. Model validation with synthetic dataset suggested that the MCR-ALS/MLPCA could extract acceptable recovered source profiles even considering relatively larger error levels. When applying to identify the sources of trace metals in soils around Miyun Reservoir, the MCR-ALS/MLPCA model obtained the highly similar profiles with PMF. On the other hand, the assessment results of contamination status showed that the soils around reservoir were polluted by trace metals in slightly moderate degree but potentially posed acceptable risks to the public. Mining activities, fertilizers and agrochemicals, and atmospheric deposition were identified as the potential anthropogenic sources with contributions of 24.8, 14.6, and 13.3 %, respectively. In order to protect the drinking water source of Beijing, special attention should be paid to the metal inputs to soils from mining and agricultural activities.

Source apportionment of settleable particles in an impacted urban and industrialized region in Brazil.

PubMed

Santos, Jane Meri; Reis, Neyval Costa; Galvão, Elson Silva; Silveira, Alexsander; Goulart, Elisa Valentim; Lima, Ana Teresa

2017-09-01

Settleable particulate matter (SPM), especially coarser particles with diameters greater than 10 μm, has been found culprit of high deposition rates in cities affected by hinterland industrial activities. This is the case of Metropolitan Region of Vitoria (MRV), Espirito Santo, Brazil where industrial facilities are located within the urban sprawl and building constructions are intense. Frequent population complaints to the environmental protection agency (IEMA) throughout the years have triggered monitoring campaigns to determine SPM deposition rates and source apportionment. Eight different locations were monitored throughout the MRV, and SPM was quantified and chemically characterized. Sources profiles were defined either by using US EPA SPECIATE data or by experimental analysis. Atmospheric fallout in the MRV ranged between 2 and 20g/(m 2 30-day), with only one monitoring station ranging from 6-10 g/(m 2 30-day). EC, OC, Fe, Al, and Si were found the main constituents of dry deposition in the region. Source apportionment by the chemical mass balance (CMB) model determined that steel and iron ore pelletizing industries were the main contributor to one of the eight locations whereas resuspension, civil construction, and vehicular sources were also very important contributors to the other stations. Quarries and soil were also considered expressive SPM sources, but at the city periphery. CMB model could differentiate contributions from six industrial source groups: thermoelectric; iron ore, pellet, and pellet furnaces; coal coke and coke oven; sintering, blast furnace, and basic oxygen furnace; and soil, resuspension, and vehicles. However, the CMB model was unable to differentiate between iron ore and pellet stockpiles which are present in both steel and iron ore pelletizing industries. Further characterization of source and SPM might be necessary to aid local authorities in decision-making regarding these two industrial sources.

SOURCES OF MERCURY WET DEPOSITION IN EASTERN OHIO, USA

EPA Science Inventory

In the fall of 2002, an enhanced air monitoring site was established in Steubenville, Ohio as part of a multi-year comprehensive mercury monitoring and source apportionment study to investigate the impact of local and regional coal combustion sources on atmospheric mercury deposi...

Trace elements and common ions in southeastern Idaho snow: Regional air pollutant tracers for source area emissions

USGS Publications Warehouse

Abbott, M.; Einerson, J.; Schuster, P.; Susong, D.; Taylor, Howard E.; ,

2004-01-01

Snow sampling and analysis methods which produce accurate and ultra-low measurements of trace elements and common ion concentration in southeastern Idaho snow, were developed. Snow samples were collected over two winters to assess trace elements and common ion concentrations in air pollutant fallout across the southeastern Idaho. The area apportionment of apportionment of fallout concentrations measured at downwind location were investigated using pattern recognition and multivariate statistical technical techniques. Results show a high level of contribution from phosphates processing facilities located outside Pocatello in the southern portion of the Eastern Snake River Plain, and no obvious source area profiles other than at Pocatello.

Atmospheric polycyclic aromatic hydrocarbons in the urban environment: Occurrence, toxicity and source apportionment.

PubMed

Mishra, Nitika; Ayoko, Godwin A; Morawska, Lidia

2016-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) represent a major class of toxic pollutants because of their carcinogenic and mutagenic characteristics. People living in urban areas are regularly exposed to PAHs because of abundance of their emission sources. Within this context, this study aimed to: (i) identify and quantify the levels of ambient PAHs in an urban environment; (ii) evaluate their toxicity; and (iii) identify their sources as well as the contribution of specific sources to measured concentrations. Sixteen PAHs were identified and quantified in air samples collected from Brisbane. Principal Component Analysis - Absolute Principal Component Scores (PCA-APCS) was used in order to conduct source apportionment of the measured PAHs. Vehicular emissions, natural gas combustion, petrol emissions and evaporative/unburned fuel were the sources identified; contributing 56%, 21%, 15% and 8% of the total PAHs emissions, respectively, all of which need to be considered for any pollution control measures implemented in urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

RECEPTOR MODEL DEVELOPMENT AND APPLICATION

EPA Science Inventory

Source apportionment (receptor) models are mathematical procedures for identifying and quantifying the sources of ambient air pollutants and their effects at a site (the receptor), primarily on the basis of species concentration measurements at the receptor, and generally without...

SOURCE APPORTIONMENT OF FINE PARTICLES IN THE U.S. AND ASSOCIATIONS BETWEEN INFLAMMATORY MARKER IL -8

EPA Science Inventory

Associations are well established between particulate matter (PM) and increased human mortality and morbidity. The association between PM sources and inflammatory marker IL-8 was evaluated in this study.

Source apportionment of trace metals in surface waters of a polluted stream using multivariate statistical analyses.

PubMed

Pekey, Hakan; Karakaş, Duran; Bakoğlu, Mithat

2004-11-01

Surface water samples were collected from ten previously selected sites of the polluted Dil Deresi stream, during two field surveys, December 2001 and April 2002. All samples were analyzed using ICP-AES, and the concentrations of trace metals (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Pb, Sn and Zn) were determined. The results were compared with national and international water quality guidelines, as well as literature values reported for similar rivers. Factor analysis (FA) and a factor analysis-multiple regression (FA-MR) model were used for source apportionment and estimation of contributions from identified sources to the concentration of each parameter. By a varimax rotated factor analysis, four source types were identified as the paint industry; sewage, crustal and road traffic runoff for trace metals, explaining about 83% of the total variance. FA-MR results showed that predicted concentrations were calculated with uncertainties lower than 15%.

Source apportionment and pollution evaluation of heavy metals in water and sediments of Buriganga River, Bangladesh, using multivariate analysis and pollution evaluation indices.

PubMed

Bhuiyan, Mohammad Amir Hossain; Dampare, Samuel B; Islam, M A; Suzuki, Shigeyuki

2015-01-01

Concentrations of heavy metals in water and sediment samples of Buriganga River in the capital city Dhaka, Bangladesh, were studied to understand the level of heavy metals and their source apportionment. The results showed that the mean concentrations of heavy metals both in water and sediment samples were very high and, in most cases, exceeded the permissible limits recommended by the Bangladesh government and other international organizations. Significantly higher concentrations of Pb, Cr, Mn, Co, Ni, Cu, Zn, As, and Cd were found in sediment samples. However, average concentrations of metals both in water and sediment samples were above the effect range median. The heavy metal pollution index (HPI) and degree of contamination (Cd) yielded different results in water samples despite significant correlations between them. The heavy metal evaluation index (HEI) showed strong correlations with HPI and Cd and provided better assessment of pollution levels. The enrichment factor (EF) and geoaccumulation index (Igeo) showed the elevated value of Cr, Pb, and Cd in access of background values. The measured elements were subjected to positive matrix factorization (PMF) and examining correlations in order to explain the content, behavior, and source apportionment of metals. PMF resulted in a successful partitioning of variances into sources related to background geochemistry and contaminant influences. However, the PMF approach successfully demarcated the major sources of metals from tannery, paint, municipal sewage, textiles, and agricultural activities.

Carbonaceous species in PM2.5 and PM10 in urban area of Zhengzhou in China: Seasonal variations and source apportionment

NASA Astrophysics Data System (ADS)

Wang, Qun; Jiang, Nan; Yin, Shasha; Li, Xiao; Yu, Fei; Guo, Yue; Zhang, Ruiqin

2017-07-01

PM2.5 and PM10 samples were simultaneously collected in an urban site in Zhengzhou, China from October 2014 to July 2015 representing the four seasons. Organic carbon (OC), elemental carbon (EC), and non-polar organic compounds including n-alkanes (C8-C40) and polycyclic aromatic hydrocarbons (PAHs) were quantified. The characteristics of their concentrations, seasonal variations, and sources of n-alkanes and PAHs were investigated. Diagnostic ratios and positive matrix factorization (PMF) were used to characterize carbonaceous species, identify their possible sources, and apportion the contributions from each possible source. The concentrations of the components exhibited distinct seasonal variation, that is, the concentrations are high in winter and low in summer. This finding could be associated with increase in air pollutant emissions during heating season and stable weather condition. The estimated total carbonaceous aerosol accounts for 32% of PM2.5 and 30% of PM10. Hence, carbonaceous compounds were the major components of particulate matter in the study area. Moreover, OC, EC, PAHs, and n-alkanes preferentially accumulated into fine particles. The carbonaceous components exhibited high correlation in PM2.5 and PM10, thereby indicating that their sources were similar. The PMF results revealed that the main sources of PAHs were coal combustion (40%) and motor vehicles (29%); n-alkanes were mainly from burning of fossil fuel (48%). These sources were consistent with the diagnostic ratios obtained. This study provides guidance for improving air quality and reducing human exposure to toxic air pollutants.

Inter-comparison of receptor models for PM source apportionment: Case study in an industrial area

NASA Astrophysics Data System (ADS)

Viana, M.; Pandolfi, M.; Minguillón, M. C.; Querol, X.; Alastuey, A.; Monfort, E.; Celades, I.

2008-05-01

Receptor modelling techniques are used to identify and quantify the contributions from emission sources to the levels and major and trace components of ambient particulate matter (PM). A wide variety of receptor models are currently available, and consequently the comparability between models should be evaluated if source apportionment data are to be used as input in health effects studies or mitigation plans. Three of the most widespread receptor models (principal component analysis, PCA; positive matrix factorization, PMF; chemical mass balance, CMB) were applied to a single PM10 data set (n=328 samples, 2002-2005) obtained from an industrial area in NE Spain, dedicated to ceramic production. Sensitivity and temporal trend analyses (using the Mann-Kendall test) were applied. Results evidenced the good overall performance of the three models (r2>0.83 and α>0.91×between modelled and measured PM10 mass), with a good agreement regarding source identification and high correlations between input (CMB) and output (PCA, PMF) source profiles. Larger differences were obtained regarding the quantification of source contributions (up to a factor of 4 in some cases). The combined application of different types of receptor models would solve the limitations of each of the models, by constructing a more robust solution based on their strengths. The authors suggest the combined use of factor analysis techniques (PCA, PMF) to identify and interpret emission sources, and to obtain a first quantification of their contributions to the PM mass, and the subsequent application of CMB. Further research is needed to ensure that source apportionment methods are robust enough for application to PM health effects assessments.

Fine Particulate Pollution and Source Apportionment in the Urban Centers for Africa, Asia and Latin America

NASA Astrophysics Data System (ADS)

Guttikunda, S. K.; Johnson, T. M.; Procee, P.

2004-12-01

Fossil fuel combustion for domestic cooking and heating, power generation, industrial processes, and motor vehicles are the primary sources of air pollution in the developing country cities. Over the past twenty years, major advances have been made in understanding the social and economic consequences of air pollution. In both industrialized and developing countries, it has been shown that air pollution from energy combustion has detrimental impacts on human health and the environment. Lack of information on the sectoral contributions to air pollution - especially fine particulates, is one of the typical constraints for an effective integrated urban air quality management program. Without such information, it is difficult, if not impossible, for decision makers to provide policy advice and make informed investment decisions related to air quality improvements in developing countries. This also raises the need for low-cost ways of determining the principal sources of fine PM for a proper planning and decision making. The project objective is to develop and verify a methodology to assess and monitor the sources of PM, using a combination of ground-based monitoring and source apportionment techniques. This presentation will focus on four general tasks: (1) Review of the science and current activities in the combined use of monitoring data and modeling for better understanding of PM pollution. (2) Review of recent advances in atmospheric source apportionment techniques (e.g., principal component analysis, organic markers, source-receptor modeling techniques). (3) Develop a general methodology to use integrated top-down and bottom-up datasets. (4) Review of a series of current case studies from Africa, Asia and Latin America and the methodologies applied to assess the air pollution and its sources.

Chemical Composition and Source Apportionment of Size Fractionated Particulate Matter in Cleveland, Ohio, USA

EPA Science Inventory

The Cleveland airshed comprises a complex mixture of industrial source emissions that contribute to periods of non-attainment for fine particulate matter (PM 2.5 ) and are associated with increased adverse health outcomes in the exposed population. Specific PM sources responsible...

Tim Watkins

EPA Pesticide Factsheets

Tim’s expertise and interests lie in the area of air pollution exposure assessment, including ambient air monitoring, personal monitoring, source apportionment, and air quality and exposure modeling.

Source apportionment of speciated PM2.5 and non-parametric regressions of PM2.5 and PM(coarse) mass concentrations from Denver and Greeley, Colorado, and construction and evaluation of dichotomous filter samplers

NASA Astrophysics Data System (ADS)

Piedrahita, Ricardo A.

The Denver Aerosol Sources and Health study (DASH) was a long-term study of the relationship between the variability in fine particulate mass and chemical constituents (PM2.5, particulate matter less than 2.5mum) and adverse health effects such as cardio-respiratory illnesses and mortality. Daily filter samples were chemically analyzed for multiple species. We present findings based on 2.8 years of DASH data, from 2003 to 2005. Multilinear Engine 2 (ME-2), a receptor-based source apportionment model was applied to the data to estimate source contributions to PM2.5 mass concentrations. This study relied on two different ME-2 models: (1) a 2-way model that closely reflects PMF-2; and (2) an enhanced model with meteorological data that used additional temporal and meteorological factors. The Coarse Rural Urban Sources and Health study (CRUSH) is a long-term study of the relationship between the variability in coarse particulate mass (PMcoarse, particulate matter between 2.5 and 10mum) and adverse health effects such as cardio-respiratory illnesses, pre-term births, and mortality. Hourly mass concentrations of PMcoarse and fine particulate matter (PM2.5) are measured using tapered element oscillating microbalances (TEOMs) with Filter Dynamics Measurement Systems (FDMS), at two rural and two urban sites. We present findings based on nine months of mass concentration data, including temporal trends, and non-parametric regressions (NPR) results, which were used to characterize the wind speed and wind direction relationships that might point to sources. As part of CRUSH, 1-year coarse and fine mode particulate matter filter sampling network, will allow us to characterize the chemical composition of the particulate matter collected and perform spatial comparisons. This work describes the construction and validation testing of four dichotomous filter samplers for this purpose. The use of dichotomous splitters with an approximate 2.5mum cut point, coupled with a 10mum cut diameter inlet head allows us to collect the separated size fractions that the collocated TEOMs collect continuously. Chemical analysis of the filters will include inorganic ions, organic compounds, EC, OC, and biological analyses. Side by side testing showed the cut diameters were in agreement with each other, and with a well characterized virtual impactor lent to the group by the University of Southern California. Error propagation was performed and uncertainty results were similar to the observed standard deviations.

Limitation of the Use of the Absorption Angstrom Exponent for Source Apportionment of Equivalent Black Carbon: a Case Study from the North West Indo-Gangetic Plain.

PubMed

Garg, Saryu; Chandra, Boggarapu Praphulla; Sinha, Vinayak; Sarda-Esteve, Roland; Gros, Valerie; Sinha, Baerbel

2016-01-19

Angstrom exponent measurements of equivalent black carbon (BCeq) have recently been introduced as a novel tool to apportion the contribution of biomass burning sources to the BCeq mass. The BCeq is the mass of ideal BC with defined optical properties that, upon deposition on the aethalometer filter tape, would cause equal optical attenuation of light to the actual PM2.5 aerosol deposited. The BCeq mass hence is identical to the mass of the total light-absorbing carbon deposited on the filter tape. Here, we use simultaneously collected data from a seven-wavelength aethalometer and a high-sensitivity proton-transfer reaction mass spectrometer installed at a suburban site in Mohali (Punjab), India, to identify a number of biomass combustion plumes. The identified types of biomass combustion include paddy- and wheat-residue burning, leaf litter, and garbage burning. Traffic plumes were selected for comparison. We find that the combustion efficiency, rather than the fuel used, determines αabs, and consequently, the αabs can be ∼1 for flaming biomass combustion and >1 for older vehicles that operate with poorly optimized engines. Thus, the absorption angstrom exponent is not representative of the fuel used and, therefore, cannot be used as a generic tracer to constrain source contributions.

Characteristics of tyre dust in polluted air: Studies by single particle mass spectrometry (ATOFMS)

NASA Astrophysics Data System (ADS)

Dall'Osto, Manuel; Beddows, David C. S.; Gietl, Johanna K.; Olatunbosun, Oluremi A.; Yang, Xiaoguang; Harrison, Roy M.

2014-09-01

There is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35 nm and 85 nm were obtained from SMPS/APS measurements over the range 6-20,000 nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000 nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z > 100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment.

Seasonal and spatial variation of organic tracers for biomass burning in PM1 aerosols from highly insolated urban areas.

PubMed

van Drooge, B L; Fontal, M; Bravo, N; Fernández, P; Fernández, M A; Muñoz-Arnanz, J; Jiménez, B; Grimalt, J O

2014-10-01

PM1 aerosol characterization on organic tracers for biomass burning (levoglucosan and its isomers and dehydroabietic acid) was conducted within the AERTRANS project. PM1 filters (N = 90) were sampled from 2010 to 2012 in busy streets in the urban centre of Madrid and Barcelona (Spain) at ground-level and at roof sites. In both urban areas, biomass burning was not expected to be an important local emission source, but regional emissions from wildfires, residential heating or biomass removal may influence the air quality in the cities. Although both areas are under influence of high solar radiation, Madrid is situated in the centre of the Iberian Peninsula, while Barcelona is located at the Mediterranean Coast and under influence of marine atmospheres. Two extraction methods were applied, i.e. Soxhlet and ASE, which showed equivalent results after GC-MS analyses. The ambient air concentrations of the organic tracers for biomass burning increased by an order of magnitude at both sites during winter compared to summer. An exception was observed during a PM event in summer 2012, when the atmosphere in Barcelona was directly affected by regional wildfire smoke and levels were four times higher as those observed in winter. Overall, there was little variation between the street and roof sites in both cities, suggesting that regional biomass burning sources influence the urban areas after atmospheric transport. Despite the different atmospheric characteristics in terms of air relative humidity, Madrid and Barcelona exhibit very similar composition and concentrations of biomass burning organic tracers. Nevertheless, levoglucosan and its isomers seem to be more suitable for source apportionment purposes than dehydroabietic acid. In both urban areas, biomass burning contributions to PM were generally low (2 %) in summer, except on the day when wildfire smoke arrive to the urban area. In the colder periods the contribution increase to around 30 %, indicating that regional biomass burning has a substantial influence on the urban air quality.

Chemical composition and source apportionment of PM10 and PM2.5 in different functional areas of Lanzhou, China.

PubMed

Qiu, Xionghui; Duan, Lei; Gao, Jian; Wang, Shulan; Chai, Fahe; Hu, Jun; Zhang, Jingqiao; Yun, Yaru

2016-02-01

To elucidate the air pollution characteristics of northern China, airborne PM10 (atmospheric dynamic equivalent diameter ≤ 10 μm) and PM2.5 (atmospheric dynamic equivalent diameter ≤ 2.5 μm) were sampled in three different functional areas (Yuzhong County, Xigu District and Chengguan District) of Lanzhou, and their chemical composition (elements, ions, carbonaceous species) was analyzed. The results demonstrated that the highest seasonal mean concentrations of PM10 (369.48 μg/m(3)) and PM2.5 (295.42 μg/m(3)) were detected in Xigu District in the winter, the lowest concentration of PM2.5 (53.15 μg/m(3)) was observed in Yuzhong District in the fall and PM10 (89.60 μg/m(3)) in Xigu District in the fall. The overall average OC/EC (organic carbon/elemental carbon) value was close to the representative OC/EC ratio for coal consumption, implying that the pollution of Lanzhou could be attributed to the burning of coal. The content of SNA (the sum of sulfate, nitrate, ammonium, SNA) in PM2.5 in Yuzhong County was generally lower than that at other sites in all seasons. The content of SNA in PM2.5 and PM10 in Yuzhong County was generally lower than that at other sites in all seasons (0.24-0.38), indicating that the conversion ratios from precursors to secondary aerosols in the low concentration area was slower than in the area with high and intense pollutants. Six primary particulate matter sources were chosen based on positive matrix factorization (PMF) analysis, and emissions from dust, secondary aerosols, and coal burning were identified to be the primary sources responsible for the particle pollution in Lanzhou. Copyright © 2015. Published by Elsevier B.V.

OM/OC Ratio and Specific Attenuation Coefficient in Ambient Particulate Matter at a Rural Site in Southern Ontario: Implications for Aerosol Aging and Emission Sources

NASA Astrophysics Data System (ADS)

Chan, T. W.; Huang, L.; Leaitch, R.; Sharma, S.; Brook, J.; Slowik, J.; Abbatt, J.

2008-05-01

Carbonaceous species (organic carbon (OC) and elemental carbon (EC)) contribute a large portion of atmospheric fine particle mass and influence air quality, human health, and climate forcing. However, their emission sources and atmospheric aging processes are not well understood. The OM/OC ratio, defined as the organic mass per unit OC mass, is useful to understand the degree of oxidation of aerosol particles in atmospheric processes. We define the modified BC/EC (mod BC/EC) ratio as the ratio of the non-scattering corrected absorption coefficient per unit mass of EC. The mod BC/EC ratio has a similar meaning as the site specific attenuation coefficient, which is an important parameter used to convert light absorption measurements to black carbon mass. The mod BC/EC ratio can vary due to light scattering effect on absorption measurements, in which the oxygenated organics may play a role. The pyrolysis organic carbon (POC) is defined as the carbon mass fraction obtained at T= 870°C under a pure helium environment using the thermal separation method [Huang et al., 2006]. Since POC mass is generally proportional to the amount of oxygenated OC, studying the relationships among OC, EC, POC, as well as OM/OC and mod BC/EC ratios may help us understand the mechanisms of aerosol aging from different emission sources. Two 1-month field studies were conducted at a rural site in southern Ontario (NW of Toronto) during fall 2005 and spring 2007. Quartz filter samples were collected and analyzed for OC, POC, and EC concentrations using a thermal/optical method [Huang et al., 2006]. Together with the total organic matter measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and the absorption coefficient obtained from a Particle Soot Absorption Photometer (PSAP), the OM/OC and mod BC/EC ratios for ambient aerosols were obtained. Our results show that when air mass was mainly from south, OC, POC, and EC were relatively high, with average ratios of OC/EC, OM/OC, and POC/EC as 1.94, 1.41, and 0.52, respectively; this indicates significant anthropogenic impacts and relatively large portion of oxygenated OC, which might be due to either primary emissions or photo-chemical reactions occurred in a short period of time. When air mass was mainly from north, OC, POC, and EC were much lower, with average ratios of OC/EC, OM/OC, and POC/EC as 3.10, 1.20, and 0.79, respectively; this suggests less influence from anthropogenic emissions and relatively aged air mass from biogenic-source dominated clean air. Using POC, we estimate the specific attenuation at the site to be 5.8 m2 g-1 independent of the air mass origin. The relationships among OM/OC, mod BC/EC, and POC will be further discussed. References: Huang, L., Brook, J.R., Zhang, W., Li, S.M., Graham, L., Ernst, D., Chivulescu, A., and Lu, G. (2006) Stable isotope measurements of carbon fractions (OC/EC) in airborne particulate: a new dimension for source characterization and apportionment, Atmospheric Environment, 40, 2690-2705.

Spatio-temporal patterns and source apportionment of pollution in Qiantang River (China) using neural-based modeling and multivariate statistical techniques

NASA Astrophysics Data System (ADS)

Su, Shiliang; Zhi, Junjun; Lou, Liping; Huang, Fang; Chen, Xia; Wu, Jiaping

Characterizing the spatio-temporal patterns and apportioning the pollution sources of water bodies are important for the management and protection of water resources. The main objective of this study is to describe the dynamics of water quality and provide references for improving river pollution control practices. Comprehensive application of neural-based modeling and different multivariate methods was used to evaluate the spatio-temporal patterns and source apportionment of pollution in Qiantang River, China. Measurement data were obtained and pretreated for 13 variables from 41 monitoring sites for the period of 2001-2004. A self-organizing map classified the 41 monitoring sites into three groups (Group A, B and C), representing different pollution characteristics. Four significant parameters (dissolved oxygen, biochemical oxygen demand, total phosphorus and total lead) were identified by discriminant analysis for distinguishing variations of different years, with about 80% correct assignment for temporal variation. Rotated principal component analysis (PCA) identified four potential pollution sources for Group A (domestic sewage and agricultural pollution, industrial wastewater pollution, mineral weathering, vehicle exhaust and sand mining), five for Group B (heavy metal pollution, agricultural runoff, vehicle exhaust and sand mining, mineral weathering, chemical plants discharge) and another five for Group C (vehicle exhaust and sand mining, chemical plants discharge, soil weathering, biochemical pollution, mineral weathering). The identified potential pollution sources explained 75.6% of the total variances for Group A, 75.0% for Group B and 80.0% for Group C, respectively. Receptor-based source apportionment was applied to further estimate source contributions for each pollution variable in the three groups, which facilitated and supported the PCA results. These results could assist managers to develop optimal strategies and determine priorities for river pollution control and effective water resources management.

Source apportionment of VOCs and the contribution to photochemical ozone formation during summer in the typical industrial area in the Yangtze River Delta, China

NASA Astrophysics Data System (ADS)

Shao, Ping; An, Junlin; Xin, Jinyuan; Wu, Fangkun; Wang, Junxiu; Ji, Dongsheng; Wang, Yuesi

2016-07-01

Volatile organic compounds (VOCs) were continuously observated in a northern suburb of Nanjing, a typical industrial area in the Yangtze River Delta, in a summer observation period from 15th May to 31st August 2013. The average concentration of total VOCs was (34.40 ± 25.20) ppbv, including alkanes (14.98 ± 12.72) ppbv, alkenes (7.35 ± 5.93) ppbv, aromatics (9.06 ± 6.64) ppbv and alkynes (3.02 ± 2.01) ppbv, respectively. Source apportionment via Positive Matrix Factorization was conducted, and six major sources of VOCs were identified. The industry-related sources, including industrial emissions and industrial solvent usage, occupied the highest proportion, accounting for about 51.26% of the VOCs. Vehicular emissions occupied the second highest proportion, accounting for about 34.08%. The rest accounted for about 14.66%, including vegetation emission and liquefied petroleum gas/natural gas usage. Contributions of VOCs to photochemical O3 formation were evaluated by the application of a detailed chemical mechanism model (NCAR MM). Alkenes were the dominant contributors to the O3 photochemical production, followed by aromatics and alkanes. Alkynes had a very small impact on photochemical O3 formation. Based on the outcomes of the source apportionment, a sensitivity analysis of relative O3 reduction efficiency (RORE), under different source removal regimes such as using the reduction of VOCs from 10% to 100% as input, was conducted. The RORE was the highest (~ 20%-40%) when the VOCs from solvent-related sources decreased by 40%. The highest RORE values for vegetation emissions, industrial emissions, vehicle exhaust, and LPG/NG usage were presented in the scenarios of 50%, 80%, 40% and 40%, respectively.

The application of carbon-14 analyses to the source apportionment of atmospheric carbonaceous particulate matter: a review.

PubMed

Heal, Mathew R

2014-01-01

Organic carbon (OC) and elemental carbon (EC) together constitute a substantial proportion of airborne particulate matter (PM). Insight into the sources of this major contributor to PM is important for policies to mitigate the impact of PM on human health and climate change. In recent years measurement of the abundance of the radioisotope of carbon ((14)C) in samples of PM by accelerator mass spectrometry has been used to help quantify the relative contributions from sources of fossil carbon and contemporary carbon. This review provides an introduction to the different sources of carbon within PM and the role of (14)C measurements, a description of the preparation of PM samples and of the instrumentation used to quantify (14)C, and a summary of the results and source apportionment methods reported in published studies since 2004. All studies report a sizable fraction of the carbonaceous PM as of non-fossil origin. Even for PM collected in urban locations, the proportions of non-fossil carbon generally exceed 30%; typically the proportion in urban background locations is around 40-60% depending on the local influence of biomass burning. Where values have been measured directly, proportions of non-fossil carbon in EC are lower than in OC, reflecting the greater contribution of fossil-fuel combustion to EC and the generally small sources of contemporary EC. Detailed source apportionment studies point to important contributions from biogenic-derived secondary OC, consistent with other evidence of a ubiquitous presence of heavily oxidized background secondary OC. The review concludes with some comments on current issues and future prospects, including progress towards compound-class and individual-compound-specific (14)C analyses.

Biomass burning contributed most to the human cancer risk exposed to the soil-bound PAHs from Chengdu Economic Region, western China.

PubMed

Zheng, Huang; Xing, Xinli; Hu, Tianpeng; Zhang, Yuan; Zhang, Jiaquan; Zhu, Gehao; Li, Ying; Qi, Shihua

2018-05-03

The purpose of this study was to assess the human cancer risk due to the exposure to the soil-bound polycyclic aromatic hydrocarbons (PAHs) from Chengdu Economic Region (CER), western China with the main concern on cancer risk source apportionment. The total concentrations of sixteen PAHs ranged from 12.5 to 75431 ng g -1 , with a mean value of 3106 ng g -1 , which suggested that the most areas of CER were contaminated. Source apportionment of PAHs was conducted by the positive matrix factorization (PMF) model and the biomass burning contributed most (63.6%) to the total PAHs, followed by petroleum combustion (16.0%), coke source (11.3%), and petrogenic source (9.2%). Results from incremental lifetime cancer risk (ILCR) calculation showed that soil ingestion exerted the highest cancer risk (accounted for 98.1 - 99.3% of the total cancer risk) on human health among three different exposure pathways, followed by dermal contact (0.66 - 1.83%) and inhalation (0.03 - 0.04%). Among different age groups, adult suffered the highest cancer risk via any exposure pathways. Based on PMF and ILCR methods, the cancer risk source apportionment was conducted and the biomass burning showed moderate cancer risk. The petrogenic, coke, and petroleum sources showed low cancer risks to human. To analyze the sensitivity of the parameters used in ILCR calculation, Monte Carlo simulation was employed. The results indicated that the contribution of each source and exposure duration (ED) were the influential parameters on human health associated with soil-bound PAHs. Therefore, much attentions should be paid to biomass burning to avoid cumulative cancer risk. Copyright © 2018 Elsevier Inc. All rights reserved.

Source apportionment of lead in the blood of women of reproductive age living near tailings in Taxco, Guerrero, Mexico: An isotopic study.

PubMed

Vázquez Bahéna, Analine Berenice; Talavera Mendoza, Oscar; Moreno Godínez, Ma Elena; Salgado Souto, Sergio Adrián; Ruiz, Joaquín; Huerta Beristain, Gerardo

2017-04-01

The concentration and isotopic composition of lead in the blood of forty seven women of reproductive age (15-45y) exposed to multiple sources in two rural communities of the mining region of Taxco, Guerrero in southern Mexico were determined in order to identify specific contributing sources and their apportionment and to trace probable ingestion pathways. Our data indicate that >36% of the studied women have blood lead concentrations above 10μgdL -1 and up to 87% above 5μgdL -1 . Tailings contain between 2128 and 5988mgkg -1 of lead and represent the most conspicuous source in the area. Lead contents in indoor dust are largely variable (21.7-987mgkg -1 ) but only 15% of samples are above the Mexican Regulatory Guideline for urban soils (400mgkg -1 ). By contrast, 85% of glazed containers (range: 0.026-68.6mgkg -1 ) used for cooking and food storage are above the maximum 2mgL -1 of soluble lead established in the Mexican Guideline. The isotopic composition indicates that lead in the blood of 95% of the studied women can be modeled in terms of a mixing system between local ores (and derivatives), glazed pottery and Morelos bedrock, end-members, with the two former being largely the most important contributors. Only one sample shows influence of indoor paints. Indoor dust is dominated by ores and derivatives but some samples show evidence of contribution from a less radiogenic source very likely represented by interior paints. This study supports the application of lead isotopic ratios to identify potential sources and their apportionment in humans exposed to multiple sources of lead from both, natural and anthropogenic origin. Copyright © 2017 Elsevier B.V. All rights reserved.

Inverse modeling to estimate local source contributions in a complex environment with nearby port, airport, highway, and industrial sources

EPA Science Inventory

Source apportionment is challenging in urban environments with clustered sourceemissions that have similar chemical signatures. A field and inverse modeling studywas conducted in Elizabeth, New Jersey to observe gaseous and particulate pollutionnear the Port of New York and New J...

77 FR 11914 - Approval and Promulgation of Air Quality Implementation Plans; Vermont; Regional Haze

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-28

... United States. Through source apportionment modeling, MANE-VU assisted States in determining their... Contributions of Pollutants to Visibility Impairments 2. Procedure for Identifying Sources To Evaluate for... is visibility impairment that is produced by a multitude of sources and activities which are located...

SOURCE APPORTIONMENT RESULTS, UNCERTAINTIES, AND MODELING TOOLS

EPA Science Inventory

Advanced multivariate receptor modeling tools are available from the U.S. Environmental Protection Agency (EPA) that use only speciated sample data to identify and quantify sources of air pollution. EPA has developed both EPA Unmix and EPA Positive Matrix Factorization (PMF) and ...

Size distribution of particle-phase sugar and nitrophenol tracers during severe urban haze episodes in Shanghai

NASA Astrophysics Data System (ADS)

Li, Xiang; Jiang, Li; Hoa, Le Phuoc; Lyu, Yan; Xu, Tingting; Yang, Xin; Iinuma, Yoshiteru; Chen, Jianmin; Herrmann, Hartmut

2016-11-01

In this study, measurements of size-resolved sugar and nitrophenol concentrations and their distributions during Shanghai haze episodes were performed. The primary goal was to track their possible source categories and investigate the contribution of biological and biomass burning aerosols to urban haze events through regional transport. The results showed that levoglucosan had the highest concentration (40-852 ng m-3) followed by 4-nitrophenol (151-768 ng m-3), sucrose (38-380 ng m-3), 4-nitrocatechol (22-154 ng m-3), and mannitol (5-160 ng m-3). Size distributions exhibited over 90% of levoglucosan and 4-nitrocatechol to the total accumulated in the fine-particle size fraction (<2.1 μm), particularly in heavier haze periods. The back trajectories further supported the fact that levoglucosan was linked to biomass-burning particles, with higher values of associated with air masses passing from biomass burning areas (fire spots) before reaching Shanghai. Other primary saccharide and nitrophenol species showed an unusually large peak in the coarse-mode size fraction (>2.1 μm), which can be correlated with emissions from local sources (biological emission). Principal component analysis (PCA) and positive matrix factorization (PMF) revealed four probable sources (biomass burning: 28%, airborne pollen: 25%, fungal spores: 24%, and combustion emission: 23%) responsible for urban haze events. Taken together, these findings provide useful insight into size-resolved source apportionment analysis via molecular markers for urban haze pollution events in Shanghai.

Chemical characterization of fine organic aerosol for source apportionment at Monterrey, Mexico

NASA Astrophysics Data System (ADS)

Mancilla, Y.; Mendoza, A.; Fraser, M. P.; Herckes, P.

2015-07-01

Primary emissions from anthropogenic and biogenic sources as well as secondary formation are responsible for the pollution levels of ambient air in major urban areas. These sources release fine particles into the air that negatively impact human health and the environment. Organic molecular markers, which are compounds that are unique to specific PM2.5 sources, can be utilized to identify the major emission sources in urban areas. In this study, 43 representative PM2.5 samples, for both daytime and nighttime periods, were built from individual samples collected in an urban site of the Monterrey Metropolitan Area (MMA) during the spring and fall of 2011 and 2012. The samples were analyzed for organic carbon, elemental carbon, and organic molecular markers. Several diagnostic tools were employed for the preliminary identification of emission sources. Organic compounds for eight compound classes were quantified. The n-alkanoic acids were the most abundant, followed by n-alkanes, wood smoke markers, and levoglucosan/alkenoic acids. Polycyclic aromatic hydrocarbons (PAHs) and hopanes were less abundant. The carbon preference index (0.7-2.6) for n-alkanes indicate a major contribution of anthropogenic and mixed sources during the fall and the spring, respectively. Hopanes levels confirmed the contribution from gasoline and diesel engines. In addition, the contribution of gasoline and diesel vehicle exhaust was confirmed and identified by the PAH concentrations in PM2.5. Diagnostic ratios of PAH showed emissions from burning coal, wood, biomass, and other fossil fuels. The total PAH and elemental carbon (EC) were correlated (r2 = 0.39-0.70) across the monitoring periods, reinforcing that motor vehicles are the major contributors of PAH. Cholesterol levels remained constant during the spring and fall, showing evidence of the contribution of meat cooking operations, while the isolated concentrations of levoglucosan suggested occasional biomass burning events. Finally, source attribution results obtained using the CMB model indicate that emissions from motor vehicle exhausts are the most important, accounting for the 64 % of the PM2.5. The vegetative detritus and biomass burning had the smallest contribution (2.2 % of the PM2.5). To our knowledge, this is the second study to explore the broad chemical characterization of fine organic aerosol in Mexico and the first for the MMA.

Impacts of Oil and Gas Production on Winter Ozone Pollution in the Uintah Basin Using Model Source Apportionment

NASA Astrophysics Data System (ADS)

Tran, H. N. Q.; Tran, T. T.; Mansfield, M. L.; Lyman, S. N.

2014-12-01

Contributions of emissions from oil and gas activities to elevated ozone concentrations in the Uintah Basin - Utah were evaluated using the CMAQ Integrated Source Apportionment Method (CMAQ-ISAM) technique, and were compared with the results of traditional budgeting methods. Unlike the traditional budgeting method, which compares simulations with and without emissions of the source(s) in question to quantify its impacts, the CMAQ-ISAM technique assigns tags to emissions of each source and tracks their evolution through physical and chemical processes to quantify the final ozone product yield from the source. Model simulations were performed for two episodes in winter 2013 of low and high ozone to provide better understanding of source contributions under different weather conditions. Due to the highly nonlinear ozone chemistry, results obtained from the two methods differed significantly. The growing oil and gas industry in the Uintah Basin is the largest contributor to the elevated zone (>75 ppb) observed in the Basin. This study therefore provides an insight into the impact of oil and gas industry on the ozone issue, and helps in determining effective control strategies.

A Bayesian Multivariate Receptor Model for Estimating Source Contributions to Particulate Matter Pollution using National Databases.

PubMed

Hackstadt, Amber J; Peng, Roger D

2014-11-01

Time series studies have suggested that air pollution can negatively impact health. These studies have typically focused on the total mass of fine particulate matter air pollution or the individual chemical constituents that contribute to it, and not source-specific contributions to air pollution. Source-specific contribution estimates are useful from a regulatory standpoint by allowing regulators to focus limited resources on reducing emissions from sources that are major contributors to air pollution and are also desired when estimating source-specific health effects. However, researchers often lack direct observations of the emissions at the source level. We propose a Bayesian multivariate receptor model to infer information about source contributions from ambient air pollution measurements. The proposed model incorporates information from national databases containing data on both the composition of source emissions and the amount of emissions from known sources of air pollution. The proposed model is used to perform source apportionment analyses for two distinct locations in the United States (Boston, Massachusetts and Phoenix, Arizona). Our results mirror previous source apportionment analyses that did not utilize the information from national databases and provide additional information about uncertainty that is relevant to the estimation of health effects.

Size resolved fog water chemistry and its atmospheric implications

NASA Astrophysics Data System (ADS)

Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida; Ervens, Barbara; Bhattu, Deepika

2015-04-01

Fog is a natural meteorological phenomenon that occurs throughout the world. It usually contains substantial quantity of liquid water and results in severe visibility reduction leading to disruption of normal life. Fog is generally seen as a natural cleansing agent but it also has the potential to form Secondary Organic Aerosol (SOA) via aqueous processing of ambient aerosols. Size- resolved fog water chemistry for inorganics were reported in previous studies but processing of organics inside the fog water and quantification of aqSOA remained a challenge. To assess the organics processing via fog aqueous processing, size resolved fog water samples were collected in two consecutive winter seasons (2012-13, 2013-14) at Kanpur, a heavily polluted urban area of India. Caltech 3 stage fog collector was used to collect the fog droplets in 3 size fraction; coarse (droplet diameter > 22 µm), medium (22> droplet diameter >16 µm) and fine (16> droplet diameter >4 µm). Collected samples were atomized into various instruments such as Aerosol Mass Spectrometer (AMS), Cloud Condensation Nucleus Counter (CCNc), Total Organic Carbon (TOC) and a thermo denuder (TD) for the physico-chemical characterization of soluble constituents. Fine droplets are found to be more enriched with different aerosol species and interestingly contain more aged and less volatile organics compared to other coarser sizes. Organics inside fine droplets have an average O/C = 0.87 compared to O/C of 0.67 and 0.74 of coarse and medium droplets. Metal chemistry and higher residence time of fine droplets are seemed to be the two most likely reasons for this outcome from as the results of a comprehensive modeling carried out on the observed data indicate. CCN activities of the aerosols from fine droplets are also much higher than that of coarse or medium droplets. Fine droplets also contain light absorbing material as was obvious from their 'yellowish' solution. Source apportionment of fog water organics via PMF (Positive matrix factorization) revealed presence of some very highly oxidized OA inside fog water samples. From PMF results a method for aqSOA estimation is developed and aqSOA was found to be substantially contributing to total SOA. These findings indicate that light fog with large number of fine droplets can process the ambient aerosols more efficiently than very dense fog with larger droplets where scavenging becomes more important. These findings also highlight the need of incorporating fog size resolved chemistry along with metal chemistry into global models for accurately predicting aqSOA formation and contribution to total organic aerosol loading.

Heavy metal contamination status and source apportionment in sediments of Songhua River Harbin region, Northeast China.

PubMed

Li, Ning; Tian, Yu; Zhang, Jun; Zuo, Wei; Zhan, Wei; Zhang, Jian

2017-02-01

The Songhua River represents one of the seven major river systems in China. It flows through Harbin city with 66 km long, locating in the northern China with a longer winter time. This paper aimed to study concentration distributions, stability, risk assessment, and source apportionment of heavy metals including chromium (Cr), cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), copper (Cu), zinc (Zn), and nickel (Ni) in 11 selected sections of the Songhua River Harbin region. Results showed that Cr, Cd, Pb, Hg, and As exceeded their respective geochemical background values in sediments of most monitoring sections. Compared with other important rivers and lakes in China, Cr, Hg, Cd, and As pollutions in surface sediments were above medium level. Further analysis of chemical speciation indicated that Cr and As in surface sediments were relatively stable while Pb and Cd were easily bioavailable. Correlation analysis revealed sources of these metals except As might be identical. Pollution levels and ecological risks of heavy metals in surface sediments presented higher in the mainstream region (45° 47.0' N ~ 45° 53.3' N, 126° 37.0' E ~ 126° 42.1' E). Source apportionment found Hejiagou and Ashi River were the main contributors to metal pollution of this region. Thus, anthropogenic activities along the Hejiagou and Ashi River should be restricted in order to protect the Songhua River Harbin region from metal contamination.

DEVELOPMENT OF URINARY METABOLITE BIOMARKERS TO ASSESS POPULATION EXPOSURE TO PM2.5 FROM VARIOUS COMBUSTION SOURCES

EPA Science Inventory

A primary goal of our research is to validate the use of urinary biomarkers to apportion the sources of human exposure to PM2.5. Organic source tracers have been used in source apportionment studies of ambient PM2.5 to distinguish a range of combustion sources. Both gas and par...

Receptor modeling for source apportionment of polycyclic aromatic hydrocarbons in urban atmosphere.

PubMed

Singh, Kunwar P; Malik, Amrita; Kumar, Ranjan; Saxena, Puneet; Sinha, Sarita

2008-01-01

This study reports source apportionment of polycyclic aromatic hydrocarbons (PAHs) in particulate depositions on vegetation foliages near highway in the urban environment of Lucknow city (India) using the principal components analysis/absolute principal components scores (PCA/APCS) receptor modeling approach. The multivariate method enables identification of major PAHs sources along with their quantitative contributions with respect to individual PAH. The PCA identified three major sources of PAHs viz. combustion, vehicular emissions, and diesel based activities. The PCA/APCS receptor modeling approach revealed that the combustion sources (natural gas, wood, coal/coke, biomass) contributed 19-97% of various PAHs, vehicular emissions 0-70%, diesel based sources 0-81% and other miscellaneous sources 0-20% of different PAHs. The contributions of major pyrolytic and petrogenic sources to the total PAHs were 56 and 42%, respectively. Further, the combustion related sources contribute major fraction of the carcinogenic PAHs in the study area. High correlation coefficient (R2 > 0.75 for most PAHs) between the measured and predicted concentrations of PAHs suggests for the applicability of the PCA/APCS receptor modeling approach for estimation of source contribution to the PAHs in particulates.

Urban air quality in a mid-size city - PM2.5 composition, sources and identification of impact areas: From local to long range contributions

NASA Astrophysics Data System (ADS)

Squizzato, Stefania; Cazzaro, Marta; Innocente, Elena; Visin, Flavia; Hopke, Philip K.; Rampazzo, Giancarlo

2017-04-01

Urban air quality represents a major public health burden and is a long-standing concern to European citizens. Combustion processes and traffic-related emissions represent the main primary particulate matter (PM) sources in urban areas. Other sources can also affect air quality (e.g., secondary aerosol, industrial) depending on the characteristics of the study area. Thus, the identification and the apportionment of all sources is of crucial importance to make effective corrective decisions within environmental policies. The aim of this study is to evaluate the impacts of different emissions sources on PM2.5 concentrations and compositions in a mid-size city in the Po Valley (Treviso, Italy). Data have been analyzed to highlight compositional differences (elements and major inorganic ions), to determine PM2.5 sources and their contributions, and to evaluate the influence of air mass movements. Non-parametric tests, positive matrix factorization (PMF), conditional bivariate probability function (CBPF), and concentration weighted trajectory (CWT) have been used in a multi-chemometrics approach to understand the areal-scale (proximate, local, long-range) where different sources act on PM2.5 levels and composition. Results identified three levels of scale from which the pollution arose: (i) a proximate local scale (close to the sampling site) for traffic non-exhaust and resuspended dust sources; (ii) a local urban scale (including both sampling site and areas close to them) for combustion and industrial; and (iii) a regional scale characterized by ammonium nitrate and ammonium sulfate. This approach and results can help to develop and adopt better air quality policy action.

Characterization of Aral Sea Particulate Matter in Kyrgyzstan

EPA Science Inventory

1. Elemental analyses of resuspendable soils from the Aral Sea region and Kyrgyz soils show that the composition of the soils are remarkably uniform thereby supporting chemical source apportionment models that treat this region as a homogeneous source with respect to elemental co...

PARTICLE SPECIATION AND EMISSION PROFILES OF SMALL 2-STROKE ENGINES

EPA Science Inventory

The Human Exposure and Atmospheric Sciences Division (HEASD) conducts studies designed to acquire information from emission sources for use in source apportionment studies. The objective of this work is to characterize a complete, speciated emission profile (PM and air toxics) ...

Size distribution of chemical elements and their source apportionment in ambient coarse, fine, and ultrafine particles in Shanghai urban summer atmosphere.

PubMed

Lü, Senlin; Zhang, Rui; Yao, Zhenkun; Yi, Fei; Ren, Jingjing; Wu, Minghong; Feng, Man; Wang, Qingyue

2012-01-01

Ambient coarse particles (diameter 1.8-10 microm), fine particles (diameter 0.1-1.8 microm), and ultrafine particles (diameter < 0.1 microm) in the atmosphere of the city of Shanghai were sampled during the summer of 2008 (from Aug 27 to Sep 08). Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX). Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence (SRXRF). Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 +/- 2.18, 8.82 +/- 3.52, and 2.02 +/- 0.41 microg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.

Characterization of Arctic elemental carbon in Barrow, AK using radiocarbon source apportionment

NASA Astrophysics Data System (ADS)

Barrett, T. E.; Usenko, S.; Robinson, E. M.; Sheesley, R. J.

2013-12-01

Currently, the Arctic is one of the fastest warming regions on earth with surface temperatures increasing at a rate nearly double the global mean over recent decades. Despite the fact that atmospheric concentrations of elemental carbon (EC) are lower in the Arctic than in lower latitudes, deposition of EC on snow and ice may exacerbate regional warming by simultaneously decreasing albedo and increasing melt rates. Due to the intensifying Arctic oil exploration in areas such as the Beaufort and Chukchi seas, the impact of new emission sources such as heavy fuel and heavy diesel combustion on regional carbon needs to be assessed. The first step in developing mitigation strategies for reducing current and future EC emissions in the Arctic is to determine emission source contributions. This study aims to determine the relative contributions of fossil fuel and biomass combustion and to identify major source regions of EC to the Arctic. Radiocarbon analysis of both total organic carbon (TOC) and EC combined with organic tracer and back trajectory analysis has been applied to a set of wintertime coarse particulate matter (PM10) samples from Barrow, AK. Preliminary apportionment for January 2013 indicates roughly half of TOC is from biogenic/biomass burning emissions and one third of EC is due to biomass burning emissions. The radiocarbon results will be combined with organic tracer analysis (polycyclic aromatic hydrocarbons, petroleum biomarkers and normal alkanes), increasing the specificity of the relative contribution of both the fossil and modern (biogenic/biomass burning) carbon emission sources. This research represents the first reported radiocarbon values for Arctic EC, providing highly conclusive source apportionment prior to the influence of increased drilling operations and ship traffic in the Beaufort and Chukchi seas.

Source apportionment of trace metals in river sediments: A comparison of three methods.

PubMed

Chen, Haiyang; Teng, Yanguo; Li, Jiao; Wu, Jin; Wang, Jinsheng

2016-04-01

Increasing trace metal pollution in river sediment poses a significant threat to watershed ecosystem health. Identifying potential sources of sediment metals and apportioning their contributions are of key importance for proposing prevention and control strategies of river pollution. In this study, three advanced multivariate receptor models, factor analysis with nonnegative constraints (FA-NNC), positive matrix factorization (PMF), and multivariate curve resolution weighted-alternating least-squares (MCR-WALS), were comparatively employed for source apportionment of trace metals in river sediments and applied to the Le'an River, a main tributary of Poyang Lake which is the largest freshwater lake in China. The pollution assessment with contamination factor and geoaccumulation index suggested that the river sediments in Le'an River were contaminated severely by trace metals due to human activities. With the three apportionment tools, similar source profiles of trace metals in sediments were extracted. Especially, the MCR-WALS and PMF models produced essentially the same results. Comparatively speaking, the weighted schemes might give better solutions than the unweighted FA-NNC because the uncertainty information of environmental data was considered by PMF and MCR-WALS. Anthropogenic sources were apportioned as the most important pollution sources influencing the sediment metals in Le'an River with contributions of about 90%. Among them, copper tailings occupied the largest contribution (38.4-42.2%), followed by mining wastewater (29.0-33.5%), and agricultural activities (18.2-18.7%). To protect the ecosystem of Le'an River and Poyang Lake, special attention should be paid to the discharges of mining wastewater and the leachates of copper tailing ponds in that region. Copyright © 2015 Elsevier Ltd. All rights reserved.

26 CFR 1.168(i)-0 - Table of contents for the general asset account rules.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) Source of ordinary income, gain, or loss. (i) Source determined by allocation and apportionment of depreciation allowed. (ii) Formula for determining foreign source income, gain, or loss. (3) Section 904(d... disposed or converted asset. (k) Effect of adjustments on prior dispositions. (l) Election. (1) Irrevocable...

26 CFR 1.168(i)-0 - Table of contents for the general asset account rules.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) Source of ordinary income, gain, or loss. (i) Source determined by allocation and apportionment of depreciation allowed. (ii) Formula for determining foreign source income, gain, or loss. (3) Section 904(d... disposed or converted asset. (k) Effect of adjustments on prior dispositions. (l) Election. (1) Irrevocable...

26 CFR 1.168(i)-0 - Table of contents for the general asset account rules.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) Source of ordinary income, gain, or loss. (i) Source determined by allocation and apportionment of depreciation allowed. (ii) Formula for determining foreign source income, gain, or loss. (3) Section 904(d... disposed or converted asset. (k) Effect of adjustments on prior dispositions. (l) Election. (1) Irrevocable...

DeltaSA tool for source apportionment benchmarking, description and sensitivity analysis

NASA Astrophysics Data System (ADS)

Pernigotti, D.; Belis, C. A.

2018-05-01

DeltaSA is an R-package and a Java on-line tool developed at the EC-Joint Research Centre to assist and benchmark source apportionment applications. Its key functionalities support two critical tasks in this kind of studies: the assignment of a factor to a source in factor analytical models (source identification) and the model performance evaluation. The source identification is based on the similarity between a given factor and source chemical profiles from public databases. The model performance evaluation is based on statistical indicators used to compare model output with reference values generated in intercomparison exercises. The references values are calculated as the ensemble average of the results reported by participants that have passed a set of testing criteria based on chemical profiles and time series similarity. In this study, a sensitivity analysis of the model performance criteria is accomplished using the results of a synthetic dataset where "a priori" references are available. The consensus modulated standard deviation punc gives the best choice for the model performance evaluation when a conservative approach is adopted.

Distribution and source apportionment of polycyclic aromatic hydrocarbons in surface sediments from Zhoushan Archipelago and Xiangshan Harbor, East China Sea.

PubMed

Wang, Xiaoyan; Xu, Huanzhi; Zhou, Yongdong; Wu, Changwen; Kanchanopas-Barnette, Praparsiri

2015-12-30

Zhoushan Archipelago and the adjacent Xiangshan Harbor are important commercial, tourism, fishing, and mariculture areas. Considering the concern on the effects of anthropogenic activities on the environment, the level and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments were investigated. The sum of 16 PAH (∑16 PAH) concentrations in the Zhoushan Archipelago ranged from 3.67 to 31.30 ng g(-1) d.w., with a mean of 15.01 ± 1.21 ng g(-1) d.w., and that in Xiangshan Harbor varied from 11.58 to 481.44 ng g(-1) d.w., with a mean of 62.52 ± 32.85 ng g(-1) d.w. Diagnostic ratios and factor analysis were performed to identify PAH sources. Results show that PAHs have mixed origins (i.e., traffic-related sources, coal combustion, petrogenic sources, and biomass burning), with pyrolytic-related pollution as the dominant source. This study provided a baseline to promote environmental protection and pollution episode monitoring in the East China Sea. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spatiotemporal distribution and source apportionment of low molecular weight organic acids in wet precipitation at a coastal city, China.

PubMed

Du, Wenjiao; Hong, Zhenyu; Chen, Yanting; Deng, Junjun; Chen, Jinsheng; Xu, Lingling; Hong, Youwei; Xiao, Hang

2017-03-01

To investigate the characteristics and sources of low molecular weight (LMW) organic acids in wet precipitation at a coastal city, Xiamen, a total of 313 rainwater samples were collected at seven different functional areas from September 2012 to August 2013. Spatiotemporal characteristics of LMW organic acids as well as pH and electrical conductivity were analyzed. Meanwhile, air mass clusters in different seasons and the positive matrix factorization (PMF) source apportion model were comprehensively used to identify the sources of organic acids. In conclusion, the volume-weighted mean (VWM) concentration of formic (3.20 μmol/L), acetic (1.84 μmol/L), lactic (0.44 μmol/L), and oxalic acid (0.53 μmol/L) were obtained, which jointly contributed to 4.33% of the total free acidity (TFA). At the same time, the highest wet deposition flux of LMW organic acids and contribution of that to TFA were achieved at the forest protection area during growing season in Xiamen. In addition, biogenic emissions (77.12%), sea salts (13.77%), regional agriculture activities (3.92%), soil emissions (2.56%), biomass burning (1.47%), and secondary aerosols (1.15%) were determined as the source of LMW organic acids. Besides, the dominancy of biomass burning via long-range transport in non-growing season (NGS) and the contribution of biogenic emission in growing season (GS) were recognized. Finally, the considerable influence of sea salts on the LMW organic acids (13.77%) in Xiamen was quantified, especially for oxalic acid.

RADIOCARBON SOURCE APPORTIONMENT IN A BIOFUELS ERA

EPA Science Inventory

Biofuels (gasohol and biodiesel) introduce radiocarbon into the U.S. mobile source fuel supply where it was previously absent. Initial measurements of radiocarbon in the PM_2.5 combustion emissions from engines using gasohol indicate that this may have less effect on r...

The source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the topsoil in Xiaodian sewage irrigation area, North of China.

PubMed

Li, Jia-Le; Wang, Yan-Xin; Zhang, Cai-Xiang; Dong, Yi-Hui; Du, Bin; Liao, Xiao-Ping

2014-12-01

31 topsoil samples were collected by grid method in Xiaodian sewage irrigation area, Taiyuan City, North of China. The concentrations of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatograph coupled with mass spectrum. Generally speaking, the distribution order of PAHs in the area is: those with five and six rings > those with four rings > those with two and three rings. Source apportionment shows a significant zonation of the source of PAHs: the civil coal pollution occurred in the north part, the local and far factory pollution happened in the middle area and the mixed pollution sources from coal and wood combustion, automotive emission, presented in the south area. The distribution of PAHs has a definite relationship with the sewage water flow and soil adsorption. The related coefficient between PAHs and physicochemical property showed there was a negative correlation between pH, silt, clay and PAHs while there was a positive correlation between total organic carbon, sand and PAHs.

Chemometric techniques in distribution, characterisation and source apportionment of polycyclic aromatic hydrocarbons (PAHS) in aquaculture sediments in Malaysia.

PubMed

Retnam, Ananthy; Zakaria, Mohamad Pauzi; Juahir, Hafizan; Aris, Ahmad Zaharin; Zali, Munirah Abdul; Kasim, Mohd Fadhil

2013-04-15

This study investigated polycyclic aromatic hydrocarbons (PAHs) pollution in surface sediments within aquaculture areas in Peninsular Malaysia using chemometric techniques, forensics and univariate methods. The samples were analysed using soxhlet extraction, silica gel column clean-up and gas chromatography mass spectrometry. The total PAH concentrations ranged from 20 to 1841 ng/g with a mean of 363 ng/g dw. The application of chemometric techniques enabled clustering and discrimination of the aquaculture sediments into four groups according to the contamination levels. A combination of chemometric and molecular indices was used to identify the sources of PAHs, which could be attributed to vehicle emissions, oil combustion and biomass combustion. Source apportionment using absolute principle component scores-multiple linear regression showed that the main sources of PAHs are vehicle emissions 54%, oil 37% and biomass combustion 9%. Land-based pollution from vehicle emissions is the predominant contributor of PAHs in the aquaculture sediments of Peninsular Malaysia. Copyright © 2013 Elsevier Ltd. All rights reserved.

Occurrence and source apportionment of sulfonamides and their metabolites in Liaodong Bay and the adjacent Liao River basin, North China.

PubMed

Jia, Ai; Hu, Jianying; Wu, Xiaoqin; Peng, Hui; Wu, Shimin; Dong, Zhaomin

2011-06-01

The presence of antibiotics in the environment is of great concern because of their potential for resistance selection among pathogens. In the present study we investigated the occurrence of 19 sulfonamides, five N-acetylated sulfonamide metabolites, and trimethoprim in the Liao River basin and adjacent Liaodong Bay, China, as well as 10 human/agricultural source samples. Within the 35 river samples, 12 sulfonamides, four acetylated sulfonamides, and trimethoprim were detected, with the dominant being sulfamethoxazole (66.6 ng/L), N-acetylsulfamethoxazole (63.1 ng/L), trimethoprim (29.0 ng/L), sulfadiazine (14.0 ng/L), and sulfamonomethoxine (8.4 ng/L); within the 36 marine samples, 10 chemicals were detected, with the main contributions from sulfamethoxazole (25.2 ng/L) and N-acetylsulfamethoxazole (28.6 ng/L). Sulfamethoxazole (25.9%), N-acetylsulfamethoxazole (46.6%), trimethoprim (22.9%), and sulfapyridine (1.4%) were the main chemicals from human sources, while sulfamonomethoxine, sulfamethazine, sulfaquinoxaline, sulfaguanidine, sulfadiazine, sulfanilamide, and sulfamethoxypyridazine were dominant in the animal husbandry sources, specifically, swine and poultry farms, and sulfamethoxazole (91%) was dominant in the mariculture source. A principal component analysis with multiple linear regression was performed to evaluate the source apportionment of total sulfonamides in Liaodong Bay. It was found that animal husbandry contributed 15.2% of total sulfonamides, while human sources contributed 28.5%, and combined human and mariculture sources contributed 56.3%. In addition, the mariculture contribution was 24.1% of total sulfonamides into the sea based on mass flux estimation. The present study is the first report that the environmental levels of sulfonamide metabolites were comparable to the corresponding parents; therefore, we should pay attention to their environmental occurrence. Source apportionment showed human discharge (60.7%) significantly contributed to these antibiotics in Liaodong Bay, which provides important information for environmental management. Copyright © 2011 SETAC.

Water Soluble Organic Nitrogen (WSON) in Ambient Fine Particles Over a Megacity in South China: Spatiotemporal Variations and Source Apportionment

NASA Astrophysics Data System (ADS)

Yu, Xu; Yu, Qingqing; Zhu, Ming; Tang, Mingjin; Li, Sheng; Yang, Weiqiang; Zhang, Yanli; Deng, Wei; Li, Guanghui; Yu, Yuegang; Huang, Zhonghui; Song, Wei; Ding, Xiang; Hu, Qihou; Li, Jun; Bi, Xinhui; Wang, Xinming

2017-12-01

Organic nitrogen aerosols are complex mixtures and important compositions in ambient fine particulate matters (PM2.5), yet their sources and spatiotemporal patterns are not well understood particularly in regions influenced by intensive human activities. In this study, filter-based ambient PM2.5 samples at four stations (one urban, two rural, plus one urban roadside) and PM samples from combustion sources (vehicle exhaust, ship emission, and biomass burning) were collected in the coastal megacity Guangzhou, south China, for determining water soluble organic nitrogen (WSON) along with other organic and inorganic species. The annual average WSON concentrations, as well as the ratios of WSON to water soluble total nitrogen, were all significantly higher at rural sites than urban sites. Average WSON concentrations at the four sites during the wet season were quite near each other, ranging from 0.41 to 0.49 μg/m3; however, they became 2 times higher at the rural sites than at the urban sites during the dry season. Five major sources for WSON were identified through positive matrix factorization analysis. Vehicle emission (29.3%), biomass burning (22.8%), and secondary formation (20.2%) were three dominant sources of WSON at the urban station, while vehicle emission (45.4%) and dust (28.6%) were two dominant sources at the urban roadside station. At the two rural sites biomass burning (51.1% and 34.1%, respectively) and secondary formation (17.8% and 30.5%, respectively) were dominant sources of WSON. Ship emission contributed 8-12% of WSON at the four sites. Natural vegetation seemed to have very minor contribution to WSON.

Spatial and temporal characteristics of PM2.5 and source apportionment in Wuhan

NASA Astrophysics Data System (ADS)

Hao, Hanzhou; Guo, Qianqian

2018-02-01

In order to study the pollution characteristics and sources of PM2.5, the PM2.5 in Wuhan atmosphere was sampled continuously. Inductively coupled plasma mass spectrometry (ICP-MS) were employed to measure Na, K, Mg, Ca, Al, Mn, Cu, Zn, As, Pb, Cr, Ni, Co, Cd, Fe, V, Ti, Hg, Si, while water soluble ions (Cl-, NO3-, SO4 2-) as well as carbonaceous mass (EC and OC) were analyzed using ion chromatograph(IC) and carbon analyzer, respectively. The results show: (1) In 2014 and 2015, Wuhan PM2.5 values were 81.4μg/m3and 69.2μg/m3 respectively far exceed the national standard level 2, i.e. annual average 35 μg/m3 in China, annual average limit 10 μg/m3 by the World Health Organization, the annual limit of 15 μg/m3 in the United States. (2) Taking Huaqiao and Qihao as research points, the Spring Festival effect of PM2.5 in Wuhan city is analyzed. It shows that the concentration of PM2.5 in 2014 and 2015 is before Spring Festival> during Spring Festival> after Spring Festival. As a backdrop, during the Spring Festival, Qihao PM2.5 concentration than Huaqiao average low 20 μg/m3. (3) The results of positive factor matrix factorization (PMF) analysis show that PM2.5 in Summer in Wuhan mainly comes from the automobile source, soil dust source, biomass combustion, industrial source, secondary aerosol source, combustion coal source, the contribution rate is 37.7%. 25%, 16.4%, 8.1%, 6.5%,6.4%, respectively.

Oxidative potential of ambient water-soluble PM2.5 measured by Dithiothreitol (DTT) and Ascorbic Acid (AA) assays in the southeastern United States: contrasts in sources and health associations

NASA Astrophysics Data System (ADS)

Fang, T.; Verma, V.; Bates, J. T.; Abrams, J.; Klein, M.; Strickland, M. J.; Sarnat, S. E.; Chang, H. H.; Mulholland, J. A.; Tolbert, P. E.; Russell, A. G.; Weber, R. J.

2015-11-01

The ability of certain components of particulate matter to induce oxidative stress through catalytic generation of reactive oxygen species (ROS) in vivo may be one mechanism accounting for observed linkages between ambient aerosols and adverse health outcomes. A variety of assays have been used to measure this so-called aerosol oxidative potential. We developed a semi-automated system to quantify oxidative potential of filter aqueous extracts utilizing the dithiothreitol (DTT) assay and have recently developed a similar semi-automated system using the ascorbic acid (AA) assay. Approximately 500 PM2.5 filter samples collected in contrasting locations in the southeastern US were analyzed using both assays. We found that water-soluble DTT activity on a per air volume basis was more spatially uniform than water-soluble AA activity. DTT activity was higher in winter than in summer/fall, whereas AA activity was higher in summer/fall compared to winter, with highest levels near highly trafficked highways. DTT activity was correlated with organic and metal species, whereas AA activity was correlated with water-soluble metals (especially water-soluble Cu, r=0.70-0.91 at most sites). Source apportionment models, Positive Matrix Factorization (PMF) and a Chemical Mass Balance Method with ensemble-averaged source impact profiles (CMB-E), suggest a strong contribution from secondary processes (e.g., organic aerosol oxidation or metal mobilization by formation of an aqueous particle with secondary acids) and traffic emissions to both DTT and AA activities in urban Atlanta. Biomass burning was a large source for DTT activity, but insignificant for AA. DTT activity was well correlated with PM2.5 mass (r=0.49-0.86 across sites/seasons), while AA activity did not co-vary strongly with mass. A linear model was developed to estimate DTT and AA activities for the central Atlanta Jefferson Street site, based on the CMB-E sources that are statistically significant with positive coefficients. The model was used to estimate oxidative potential at this site over the period 1998-2009. Time-series epidemiological analyses were conducted to assess daily emergency department (ED) visits data for the five-county Atlanta metropolitan area based on the estimated 10 year backcast oxidative potential. Results suggest that estimated DTT activity was associated with ED visits for both asthma/wheeze and congestive heart failure, while AA activity was not linked to any health outcomes. The findings point to the importance of both organic components and transition metals from biomass burning and mobile sources to adverse health outcomes in this region.

Speciated Elemental and Isotopic Characterization of Atmospheric Aerosols - Recent Advances

NASA Astrophysics Data System (ADS)

Shafer, M.; Majestic, B.; Schauer, J.

2007-12-01

Detailed elemental, isotopic, and chemical speciation analysis of aerosol particulate matter (PM) can provide valuable information on PM sources, atmospheric processing, and climate forcing. Certain PM sources may best be resolved using trace metal signatures, and elemental and isotopic fingerprints can supplement and enhance molecular maker analysis of PM for source apportionment modeling. In the search for toxicologically relevant components of PM, health studies are increasingly demanding more comprehensive characterization schemes. It is also clear that total metal analysis is at best a poor surrogate for the bioavailable component, and analytical techniques that address the labile component or specific chemical species are needed. Recent sampling and analytical developments advanced by the project team have facilitated comprehensive characterization of even very small masses of atmospheric PM. Historically; this level of detail was rarely achieved due to limitations in analytical sensitivity and a lack of awareness concerning the potential for contamination. These advances have enabled the coupling of advanced chemical characterization to vital field sampling approaches that typically supply only very limited PM mass; e.g. (1) particle size-resolved sampling; (2) personal sampler collections; and (3) fine temporal scale sampling. The analytical tools that our research group is applying include: (1) sector field (high-resolution-HR) ICP-MS, (2) liquid waveguide long-path spectrophotometry (LWG-LPS), and (3) synchrotron x-ray absorption spectroscopy (sXAS). When coupled with an efficient and validated solubilization method, the HR-ICP-MS can provide quantitative elemental information on over 50 elements in microgram quantities of PM. The high mass resolution and enhanced signal-to-noise of HR-ICP-MS significantly advance data quality and quantity over that possible with traditional quadrupole ICP-MS. The LWG-LPS system enables an assessment of the soluble/labile components of PM, while simultaneously providing critical oxidation state speciation data. Importantly, the LWG- LPS can be deployed in a semi-real-time configuration to probe fine temporal scale variations in atmospheric processing or sources of PM. The sXAS is providing complementary oxidation state speciation of bulk PM. Using examples from our research; we will illustrate the capabilities and applications of these new methods.

[Source apportionment of soil heavy metals in Jiapigou goldmine based on the UNMIX model].

PubMed

Ai, Jian-chao; Wang, Ning; Yang, Jing

2014-09-01

The paper determines 16 kinds of metal elements' concentration in soil samples which collected in Jipigou goldmine upper the Songhua River. The UNMIX Model which was recommended by US EPA to get the source apportionment results was applied in this study, Cd, Hg, Pb and Ag concentration contour maps were generated by using Kriging interpolation method to verify the results. The main conclusions of this study are: (1)the concentrations of Cd, Hg, Pb and Ag exceeded Jilin Province soil background values and enriched obviously in soil samples; (2)using the UNMIX Model resolved four pollution sources: source 1 represents human activities of transportation, ore mining and garbage, and the source 1's contribution is 39. 1% ; Source 2 represents the contribution of the weathering of rocks and biological effects, and the source 2's contribution is 13. 87% ; Source 3 is a comprehensive source of soil parent material and chemical fertilizer, and the source 3's contribution is 23. 93% ; Source 4 represents iron ore mining and transportation sources, and the source 4's contribution is 22. 89%. (3)the UNMIX Model results are in accordance with the survey of local land-use types, human activities and Cd, Hg and Pb content distributions.

PM10 source apportionment in Milan (Italy) using time-resolved data.

PubMed

Bernardoni, Vera; Vecchi, Roberta; Valli, Gianluigi; Piazzalunga, Andrea; Fermo, Paola

2011-10-15

In this work Positive Matrix Factorization (PMF) was applied to 4-hour resolved PM10 data collected in Milan (Italy) during summer and winter 2006. PM10 characterisation included elements (Mg-Pb), main inorganic ions (NH(4)(+), NO(3)(-), SO(4)(2-)), levoglucosan and its isomers (mannosan and galactosan), and organic and elemental carbon (OC and EC). PMF resolved seven factors that were assigned to construction works, re-suspended dust, secondary sulphate, traffic, industry, secondary nitrate, and wood burning. Multi Linear Regression was applied to obtain the PM10 source apportionment. The 4-hour temporal resolution allowed the estimation of the factor contributions during peculiar episodes, which would have not been detected with the traditional 24-hour sampling strategy. Copyright © 2011 Elsevier B.V. All rights reserved.

PARTICULATE ORGANIC SOURCE MARKERS IN THE NEW YORK CITY METROPOLITAN AREA

EPA Science Inventory

A sampling network of four sites was established for the Speciation of Organics for Apportionment of PM2.5 (SOAP) project during 2002-2003 to investigate composition, seasonal and spatial variability, and source contributions to particulate organic matter in the New York City met...

EPA’s Study of Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: Wastewater Source Apportionment Project

EPA Pesticide Factsheets

EPA scientists evaluated sources of bromide and other inorganic pollutants impacting drinking water intakes on the Allegheny River in Pennsylvania to examine the potential impacts related to the treatment and disposal of oil & gas well produced wastewater.

Constrained positive matrix factorization: Elemental ratios, spatial distinction, and chemical transport model source contributions

NASA Astrophysics Data System (ADS)

Sturtz, Timothy M.

Source apportionment models attempt to untangle the relationship between pollution sources and the impacts at downwind receptors. Two frameworks of source apportionment models exist: source-oriented and receptor-oriented. Source based apportionment models use presumed emissions and atmospheric processes to estimate the downwind source contributions. Conversely, receptor based models leverage speciated concentration data from downwind receptors and apply statistical methods to predict source contributions. Integration of both source-oriented and receptor-oriented models could lead to a better understanding of the implications sources have on the environment and society. The research presented here investigated three different types of constraints applied to the Positive Matrix Factorization (PMF) receptor model within the framework of the Multilinear Engine (ME-2): element ratio constraints, spatial separation constraints, and chemical transport model (CTM) source attribution constraints. PM10-2.5 mass and trace element concentrations were measured in Winston-Salem, Chicago, and St. Paul at up to 60 sites per city during two different seasons in 2010. PMF was used to explore the underlying sources of variability. Information on previously reported PM10-2.5 tire and brake wear profiles were used to constrain these features in PMF by prior specification of selected species ratios. We also modified PMF to allow for combining the measurements from all three cities into a single model while preserving city-specific soil features. Relatively minor differences were observed between model predictions with and without the prior ratio constraints, increasing confidence in our ability to identify separate brake wear and tire wear features. Using separate data, source contributions to total fine particle carbon predicted by a CTM were incorporated into the PMF receptor model to form a receptor-oriented hybrid model. The level of influence of the CTM versus traditional PMF was varied using a weighting parameter applied to an object function as implemented in ME-2. The resulting hybrid model was used to quantify the contributions of total carbon from both wildfires and biogenic sources at two Interagency Monitoring of Protected Visual Environment monitoring sites, Monture and Sula Peak, Montana, from 2006 through 2008.

Source apportionment of ambient non-methane hydrocarbons in Hong Kong: application of a principal component analysis/absolute principal component scores (PCA/APCS) receptor model.

PubMed

Guo, H; Wang, T; Louie, P K K

2004-06-01

Receptor-oriented source apportionment models are often used to identify sources of ambient air pollutants and to estimate source contributions to air pollutant concentrations. In this study, a PCA/APCS model was applied to the data on non-methane hydrocarbons (NMHCs) measured from January to December 2001 at two sampling sites: Tsuen Wan (TW) and Central & Western (CW) Toxic Air Pollutants Monitoring Stations in Hong Kong. This multivariate method enables the identification of major air pollution sources along with the quantitative apportionment of each source to pollutant species. The PCA analysis identified four major pollution sources at TW site and five major sources at CW site. The extracted pollution sources included vehicular internal engine combustion with unburned fuel emissions, use of solvent particularly paints, liquefied petroleum gas (LPG) or natural gas leakage, and industrial, commercial and domestic sources such as solvents, decoration, fuel combustion, chemical factories and power plants. The results of APCS receptor model indicated that 39% and 48% of the total NMHCs mass concentrations measured at CW and TW were originated from vehicle emissions, respectively. 32% and 36.4% of the total NMHCs were emitted from the use of solvent and 11% and 19.4% were apportioned to the LPG or natural gas leakage, respectively. 5.2% and 9% of the total NMHCs mass concentrations were attributed to other industrial, commercial and domestic sources, respectively. It was also found that vehicle emissions and LPG or natural gas leakage were the main sources of C(3)-C(5) alkanes and C(3)-C(5) alkenes while aromatics were predominantly released from paints. Comparison of source contributions to ambient NMHCs at the two sites indicated that the contribution of LPG or natural gas at CW site was almost twice that at TW site. High correlation coefficients (R(2) > 0.8) between the measured and predicted values suggested that the PCA/APCS model was applicable for estimation of sources of NMHCs in ambient air.

Two year-long continuous monitoring of PM1 aerosol chemical composition at the Cyprus Atmospheric Observatory. Source apportionment of the Organic content and geographic origins.

NASA Astrophysics Data System (ADS)

Stavroulas, Iasonas; Pikridas, Michael; Oikonomou, Kostantina; Vasiliadou, Emily; Savvides, Chrysanthos; Vrekoussis, Mihalis; Mihalopoulos, Nikolaos; Gros, Valerie; Sciare, Jean

2017-04-01

Particulate matter with diameter smaller than 1{μ}m (PM1) induces direct and indirect effects on local and regional pollution, global climate and health. As of the beginning of 2015, the chemical composition of submicron aerosols, is continuously being monitored at the newly established Cyprus Atmospheric Observatory (CAO, http://www.cyi.ac.cy/index.php/cao.html), a national facility of the ACTRIS Research Infrastructure operated by The Cyprus Institute. Cyprus, an island located in the Eastern Mediterranean Middle East region and influenced by diverse air masses throughout the year, is ideal for monitoring photochemically aged aerosols and gaseous pollutants of both natural and anthropogenic origin. Furthermore this is a unique dataset for this area in such proximity to the Middle East, a poorly documented area in terms of atmospheric aerosol observations. An Aerodyne Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) is currently deployed at the CAO premises (35.04N - 33.06E) situated at the rural area of Agia Marina Xyliatou on the foothill of mount Troodos at an elevation of 532m above sea level (asl). The ACSM delivers chemical composition of the major non-refractory aerosol (PM1) chemical constituents (organics, sulfate, nitrate, ammonium, chloride) with an effective (close to 100{%}) collection efficiency for particles in the diameter range of 65-700 nm at a 30 minute temporal resolution. Black Carbon (BC) was also monitored using both Magee Scientific AE-31 and AE-33 aethalometers. Quality control of the PM chemical dataset was conducted by comparison with chemical analysis performed on collocated 24-h filter samples (PM1) and comparison with 1-h PM2.5 derived from a Thermo Scientific TEOM (1400a) Monitor. Positive Matrix Factorization (PMF) was conducted and different organic aerosol factors were distinguished using the Igor based SoFi toolkit utilizing the ME-2 multilinear engine. Air mass origin was investigated for each measurement day using the Lagrangian dispersion model FLEXPART in backward mode. Analysis of the PMF on the organic mass spectra, based on good agreement with external standard mass spectra, led to the selection of a solution with three factors, an HOA (Hydrocarbon-like Organic Aerosol) factor with relatively low overall contribution (9{%}), a typical Low Volatility (LV-OOA) factor contributing 54{%}, and a factor attributed to Semi-Volatile organics (SV-OOA), contributing 37{%}. The FLEXPART model analysis, led to eight main regions of influence, namely Europe, West Turkey, Anatolia, Middle East, North Africa, Marine, Local and Mixed. Organic content exhibits maximum values when air masses originate from the wider northern sector (West Turkey and Anatolia) and the Middle East. Less aged organic content was identified for air masses originating from the immediate neighboring regions (West Turkey, Anatolia, Middle East and North Africa) while fresh organics peaked when air masses originated from the Middle East, coinciding with elevated BC concentrations, suggesting strong anthropogenic sources for this sector. This project received funding from the ChArMEx (Chemistry Aerosol Mediterranean Experiment) program, the ENVI-MED CyAr project, the European Union's Seventh Framework Programme (FP7) project BACCHUS under grant agreement no. 603445, and the European Union's Horizon 2020 research and innovation programme ACTRIS-2 under grant agreement No 654109.

77 FR 4510 - Air Quality Implementation Plans; Kentucky; Attainment Plan for the Kentucky Portion of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-30

... and population based apportionment of the area and nonroad sectors to support the mobile source... and nitrogen oxides (NO X ) for the mobile source contribution to ambient PM 2.5 levels for the.... Attainment Date B. Insignificance Determination for the Mobile Source Contribution to PM 2.5 and NO X...

Source identification and apportionment of halogenated compounds observed at a remote site in East Asia.

PubMed

Li, Shanlan; Kim, Jooil; Park, Sunyoung; Kim, Seung-Kyu; Park, Mi-Kyung; Mühle, Jens; Lee, Gangwoong; Lee, Meehye; Jo, Chun Ok; Kim, Kyung-Ryul

2014-01-01

The sources of halogenated compounds in East Asia associated with stratospheric ozone depletion and climate change are relatively poorly understood. High-precision in situ measurements of 18 halogenated compounds and carbonyl sulfide (COS) made at Gosan, Jeju Island, Korea, from November 2007 to December 2011 were analyzed by a positive matrix factorization (PMF). Seven major industrial sources were identified from the enhanced concentrations of halogenated compounds observed at Gosan and corresponding concentration-based source contributions were also suggested: primary aluminum production explaining 37% of total concentration enhancements, solvent usage of which source apportionment is 25%, fugitive emissions from HCFC/HFC production with 11%, refrigerant replacements (9%), semiconductor/electronics industry (9%), foam blowing agents (6%), and fumigation (3%). Statistical trajectory analysis was applied to specify the potential emission regions for seven sources using back trajectories. Primary aluminum production, solvent usage and fugitive emission sources were mainly contributed by China. Semiconductor/electronics sources were dominantly located in Korea. Refrigerant replacement, fumigation and foam blowing agent sources were spread throughout East Asian countries. The specified potential source regions are consistent with country-based consumptions and emission patterns, verifying the PMF analysis results. The industry-based emission sources of halogenated compounds identified in this study help improve our understanding of the East Asian countries' industrial contributions to halogenated compound emissions.

ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

2005-04-01

This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of September 2004 through February 2005. Significant progress was made this project period on the analysis of ambient data, source apportionment, and deterministic modeling activities. The major experimental achievement this project period was the characterization of the mercury and fine particle emissions from two modern, large, commercial pulverized coal boilers. This testing completes the field work component of the Source Characterization Activity. This report highlights results from mercury emission measurements made using a dilution sampler. The measurements clearly indicate that mercury is beingmore » transformed from an oxidized to an elemental state within the dilution. However, wall effects are significant making it difficult to determine whether or not these changes occur in the gas phase or due to some interaction with the sampler walls. This report also presents results from an analysis that uses spherical aluminum silicate (SAS) particles as a marker for primary PM{sub 2.5} emitted from coal combustion. Primary emissions from coal combustion contribute only a small fraction of the PM{sub 2.5} mass (less than 1.5% in the summer and less than 3% in the winter) at the Pittsburgh site. Ambient SAS concentrations also appear to be reasonably spatially homogeneous. Finally, SAS emission factors measured at pilot-scale are consistent with measurements made at full-scale. This report also presents results from applying the Unmix and PMF models to estimate the contribution of different sources to the PM{sub 2.5} mass concentrations in Pittsburgh using aerosol composition information. Comparison of the two models shows similar source composition and contribution for five factors: crustal material, nitrate, an Fe, Mn, and Zn factor, specialty steel production, and a cadmium factor. PMF found several additional factors. Comparison between source contributions for the similar factors shows reasonable agreement between the two models. The sulfate factor shows the highest contribution to local PM{sub 2.5} with an annual average contribution of approximately 28% (from PMF). The nitrate, crustal material, and primary OC and EC factors also show significant contributions on the order of 10-14%. The sulfate factor is affected by photochemistry and therefore shows maximum values in summer.« less

Approaches to Children’s Exposure Assessment: Case Study with Diethylhexylphthalate (DEHP)

PubMed Central

Ginsberg, Gary; Ginsberg, Justine; Foos, Brenda

2016-01-01

Children’s exposure assessment is a key input into epidemiology studies, risk assessment and source apportionment. The goals of this article are to describe a methodology for children’s exposure assessment that can be used for these purposes and to apply the methodology to source apportionment for the case study chemical, diethylhexylphthalate (DEHP). A key feature is the comparison of total (aggregate) exposure calculated via a pathways approach to that derived from a biomonitoring approach. The 4-step methodology and its results for DEHP are: (1) Prioritization of life stages and exposure pathways, with pregnancy, breast-fed infants, and toddlers the focus of the case study and pathways selected that are relevant to these groups; (2) Estimation of pathway-specific exposures by life stage wherein diet was found to be the largest contributor for pregnant women, breast milk and mouthing behavior for the nursing infant and diet, house dust, and mouthing for toddlers; (3) Comparison of aggregate exposure by pathways vs biomonitoring-based approaches wherein good concordance was found for toddlers and pregnant women providing confidence in the exposure assessment; (4) Source apportionment in which DEHP presence in foods, children’s products, consumer products and the built environment are discussed with respect to early life mouthing, house dust and dietary exposure. A potential fifth step of the method involves the calculation of exposure doses for risk assessment which is described but outside the scope for the current case study. In summary, the methodology has been used to synthesize the available information to identify key sources of early life exposure to DEHP. PMID:27376320

Chemical mass balance source apportionment of fine and PM10 in the Desert Southwest, USA

EPA Science Inventory

The Desert Southwest Coarse Particulate Matter Study was undertaken in Pinal County, Arizona, to better understand the origin and impact of sources of fine and coarse particulate matter (PM) in rural, arid regions of the U.S. southwestern desert. The desert southwest experiences ...

SOURCE APPORTIONMENT OF FINE PARTICULATE MATTER IN THE U.S. AND ASSOCIATIONS WITH LUNG INFLAMMATORY MARKERS IL -8, COX -2 AND HO -1

EPA Science Inventory

Associations are well established between particulate matter (PM) and increased human mortality and morbidity. The association between fine PM sources and lung inflammatory markers IL-8, COX-2, and HO-1 was evaluated in this study.

Close ISR Support: Re-organizing the Combined Forces Air Component Commander’s Intelligence, Surveillance and Reconnaissance Processes and Agencies

DTIC Science & Technology

2009-12-01

instruction, searching existing data sources , gathering and maintaining the data needed, and completing and reviewing the collection of information...146 1. Allocation vs. Apportionment .........................................................146 2. Collection Management Authority...290 D. MEASUREMENT AND SIGNATURE INTELLIGENCE .....................291 E. OPEN- SOURCE

Size-Differentiated Chemical Composition of Re-Suspended Soil Dust from the Desert Southwest United States

EPA Science Inventory

As part of the Desert Southwest Coarse Particulate Matter Study which characterized the composition of fine and coarse particulate matter in Pinal County, AZ, several source samples were collected from several different soil types to assist in source apportionment analysis of the...

THE WORKSHOP ON THE SOURCE APPORTIONMENT OF PM HEALTH EFFECTS: INTER-COMPARISON OF RESULTS AND IMPLICATIONS

EPA Science Inventory

While the association between exposure to ambient fine particulate matter mass (PM2.5) and human mortality is well established, the most responsible particle types/sources are not yet certain. In May 2003, the U.S. Environmental Protection Agency's Particulate Matter Centers Prog...

Behavior of the main sources that contribute to ambient PM2.5 in Santiago since 1998

NASA Astrophysics Data System (ADS)

Barraza, F.; Lambert, F.; Jorquera, H.; Villalobos, A. M.; Gallardo, L.

2016-12-01

Santiago's inhabitants have been exposed to high concentrations of fine particle matter (PM2.5) for decades. To contribute to a solution for this long-standing problem it is necessary to clearly identify and quantify the agents that contribute to ambient levels of PM2.5. We present an analysis of a long historical elemental concentrations database measured in air filter particles taken in central Santiago from April 1998 to August 2012 (1243 daily samples). We identify and quantify the main sources that contribute to PM2.5 levels using the source-receptor models PMF 5.0 and UNMIX 6.0. . The 6 main sources that contribute to outdoor PM2.5 levels were: vehicles (13.26±0.42 µg/m3), industrial sulfates (6.60±0.0.47 µg/m3), copper smelters (5.12±0.29 µg/m3), residential wood burning (4.38±0.36 µg/m3), marine aerosols (3.39±0.24 µg/m3), and urban dust (1.07±0.42 µg/m3). The unexplained fraction amounts to 1.76±0.90 µg/m3). The similar results obtained with both receptor models suggest a robust estimation of the main Santiago PM2.5 source apportionment. The analysis of the time series of these sources shows that their absolute contribution to PM2.5 levels has been decreasing during the last decade (except for urban dust which is increasing), and shows the effectiveness of government emission reduction policies. However, these improvements have not been sufficient to reduce PM2.5 concentrations to daily levels below the Chilean standard of 50 µg/m3, let alone the WHO standard of 25 µg/m3.

Characteristics and source apportionment of fine haze aerosol in Beijing during the winter of 2013

NASA Astrophysics Data System (ADS)

Shang, Xiaona; Zhang, Kai; Meng, Fan; Wang, Shihao; Lee, Meehye; Suh, Inseon; Kim, Daigon; Jeon, Kwonho; Park, Hyunju; Wang, Xuezhong; Zhao, Yuxi

2018-02-01

For PM2.5 filter samples collected daily at the Chinese Research Academy of Environmental Sciences (Beijing, China) from December of 2013 to February of 2014 (the winter period), chemical characteristics and sources were investigated with an emphasis on haze events in different alert levels. During the 3 months, the average PM2.5 concentration was 89 µg m-3, exceeding the Chinese national standard of 75 µg m-3 in 24  h. The maximum PM2.5 concentration was 307 µg m-3, which characterizes developed-type pollution (PM2.5 / PM10>0.5) in the World Health Organization criteria. PM2.5 was dominated by SO42-, NO3-, and pseudo-carbonaceous compounds with obvious differences in concentrations and proportions between non-haze and haze episodes. The non-negative matrix factorization (NMF) analysis provided reasonable PM2.5 source profiles, by which five sources were identified: soil dust, traffic emission, biomass combustion, industrial emission, and coal combustion accounting for 13, 22, 12, 28, and 25  % of the total, respectively. The dust impact increased with northwesterlies during non-haze periods and decreased under stagnant conditions during haze periods. A blue alert of heavy air pollution was characterized by the greatest contribution from industrial emissions (61  %). During the Chinese Lantern Festival, an orange alert was issued and biomass combustion was found to be the major source owing to firework explosions. Red-alert haze was almost equally contributed by local traffic and transported coal combustion emissions from the vicinity of Beijing (approximately 40  % each) that was distinguished by the highest levels of NO3- and SO42-, respectively. This study also reveals that the severity and source of haze are largely dependent on meteorological conditions.

Air quality assessment and the use of specific markers to apportion pollutants to source

NASA Astrophysics Data System (ADS)

Douce, David Stewart

The contributions of specific polluting sources to both indoor and outdoor atmospheric pollution are difficult to determine, as solid and gaseous products from different combustion sources are often similar. Sometimes, however, a marker compound can be identified that is unique to a pollution source (or at least not present in most other local combustion sources) and which will allow assessment of the contribution of that source to total atmospheric pollution.The aim of this study was to identify suitable marker compounds and methods for the apportionment (assessment of percentage contribution) of specific sources to atmospheric pollution. The sources selected were diesel exhaust emissions in outdoor, and environmental tobacco smoke (ETS) in indoor environments. Studies with controlled (laboratory) atmospheres would be followed by field studies using these methods and markers to produce apportionments for these sources to air pollution in selected environments. Initial analysis of such polluting sources was therefore the qualitative analysis of volatile compounds and particulate associated material, both organic and inorganic. Volatile organic compounds were adsorbed onto various resins, while particulate material was sampled onto various filter paper types. Organics were determined by GC-AED and GC-MS, and elements by ICP-MS.1-Nitropyrene was identified as a suitable marker for diesel particulate emissions (<5um). A large volume air sample from Sheffield city centre using 1-nitropyrene as a marker suggested that 63% of atmospheric particulate material (<5um) might be of diesel origin. However the concentration of 1-nitropyrene is low in atmospheric samples, and in the volumes used in routine sampling the amount of 1-nitropyrene was below the limit of detection on the instrument used. In an alternative approach the aliphatic alkane tetracosane (C24) was used as a diesel marker for urban air, with a 1-nitropyrene:tetracosane ratio derived from the average results from laboratory experiments with a diesel engine running at various speeds and loads. This approach yielded apportionment values ranging from 5-85% for the diesel contribution to particulate material (<5mum) in the urban air of Sheffield. No volatile marker compound was found for diesel apportionment.The contribution of ETS to atmospheric pollution has previously been estimated from the measurement of respirable suspended particulates (RSP), which was superseded by total UV absorbance and total fluorescence of a methanol extract. More recent work has suggested the use of solanesol or scopoletin as marker compounds. This thesis shows that the non specific methods overestimated the particulate contribution of ETS in some atmospheres, and that solanesol is a better marker compound than scopoletin. Preliminary studies from a small number of smokers homes and offices, with solanesol as a marker compound for particulate ETS, indicated that ETS contributions to total particulate material (<5mum) ranged from 6 to 49% in homes and 11 to 28% in offices.Pyrrole was used as a marker for ETS contribution to volatile organic pollution, and studies with controlled atmospheres with a smoking machine allowed calculation of the ratios of pyrrole to other volatile organic compounds (VOC's) in ETS. Samples from the field study were used to produce apportionment percentage levels of benzene, toluene, o-xylene and p+m-xylene associated with ETS.In addition the use of tree bark as a atmospheric sink for airborne particulates was investigated. Six nitrated polycyclic aromatic hydrocarbons associated with diesel emissions were quantified in bark extracts and levels of these were found to be highest during winter months.

Ensemble-Based Source Apportionment of Fine Particulate Matter and Emergency Department Visits for Pediatric Asthma

PubMed Central

Gass, Katherine; Balachandran, Sivaraman; Chang, Howard H.; Russell, Armistead G.; Strickland, Matthew J.

2015-01-01

Epidemiologic studies utilizing source apportionment (SA) of fine particulate matter have shown that particles from certain sources might be more detrimental to health than others; however, it is difficult to quantify the uncertainty associated with a given SA approach. In the present study, we examined associations between source contributions of fine particulate matter and emergency department visits for pediatric asthma in Atlanta, Georgia (2002–2010) using a novel ensemble-based SA technique. Six daily source contributions from 4 SA approaches were combined into an ensemble source contribution. To better account for exposure uncertainty, 10 source profiles were sampled from their posterior distributions, resulting in 10 time series with daily SA concentrations. For each of these time series, Poisson generalized linear models with varying lag structures were used to estimate the health associations for the 6 sources. The rate ratios for the source-specific health associations from the 10 imputed source contribution time series were combined, resulting in health associations with inflated confidence intervals to better account for exposure uncertainty. Adverse associations with pediatric asthma were observed for 8-day exposure to particles generated from diesel-fueled vehicles (rate ratio = 1.06, 95% confidence interval: 1.01, 1.10) and gasoline-fueled vehicles (rate ratio = 1.10, 95% confidence interval: 1.04, 1.17). PMID:25776011

Trace element contents in fine particulate matter (PM2.5) in urban school microenvironments near a contaminated beach with mine tailings, Chañaral, Chile.

PubMed

Mesías Monsalve, Stephanie; Martínez, Leonardo; Yohannessen Vásquez, Karla; Alvarado Orellana, Sergio; Klarián Vergara, José; Martín Mateo, Miguel; Costilla Salazar, Rogelio; Fuentes Alburquenque, Mauricio; Cáceres Lillo, Dante D

2018-06-01

Air quality in schools is an important public health issue because children spend a considerable part of their daily life in classrooms. Particulate size and chemical composition has been associated with negative health effects. We studied levels of trace element concentrations in fine particulate matter (PM 2.5 ) in indoor versus outdoor school settings from six schools in Chañaral, a coastal city with a beach severely polluted with mine tailings. Concentrations of trace elements were measured on two consecutive days during the summer and winter of 2012 and 2013 and determined using X-ray fluorescence. Source apportionment and element enrichment were measured using principal components analysis and enrichment factors. Trace elements were higher in indoor school spaces, especially in classrooms compared with outdoor environments. The most abundant elements were Na, Cl, S, Ca, Fe, K, Mn, Ti, and Si, associated with earth's crust. Conversely, an extremely high enrichment factor was determined for Cu, Zn, Ni and Cr; heavy metals associated with systemic and carcinogenic risk effects, whose probably origin sources are industrial and mining activities. These results suggest that the main source of trace elements in PM 2.5 from these school microenvironments is a mixture of dust contaminated with mine tailings and marine aerosols. Policymakers should prioritize environmental management changes to minimize further environmental damage and its direct impact on the health of children exposed.

Combustion aerosols: factors governing their size and composition and implications to human health.

PubMed

Lighty, J S; Veranth, J M; Sarofim, A F

2000-09-01

Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 microns (PM2.5) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-temperature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated that susceptible individuals are being harmed by ambient PM. Particle surface area, number of ultrafine particles, bioavailable transition metals, polycyclic aromatic hydrocarbons (PAH), and other particle-bound organic compounds are suspected to be more important than particle mass in determining the effects of air pollution. Time- and size-resolved PM measurements are needed for testing mechanistic toxicological hypotheses, for characterizing the relationship between combustion operating conditions and transient emissions, and for source apportionment studies to develop air quality plans. Citations are provided to more specialized reviews, and the concluding comments make suggestions for further research.

An overview of the characterization of occupational exposure to nanoaerosols in workplaces

NASA Astrophysics Data System (ADS)

Castellano, Paola; Ferrante, Riccardo; Curini, Roberta; Canepari, Silvia

2009-05-01

Currently, there is a lack of standardized sampling and metric methods that can be applied to measure the level of exposure to nanosized aerosols. Therefore, any attempt to characterize exposure to nanoparticles (NP) in a workplace must involve a multifaceted approach characterized by different sampling and analytical techniques to measure all relevant characteristics of NP exposure. Furthermore, as NP aerosols are always complex mixtures of multiple origins, sampling and analytical methods need to be improved to selectively evaluate the apportionment from specific sources to the final nanomaterials. An open question at the world's level is how to relate specific toxic effects of NP with one or more among several different parameters (such as particle size, mass, composition, surface area, number concentration, aggregation or agglomeration state, water solubility and surface chemistry). As the evaluation of occupational exposure to NP in workplaces needs dimensional and chemical characterization, the main problem is the choice of the sampling and dimensional separation techniques. Therefore a convenient approach to allow a satisfactory risk assessment could be the contemporary use of different sampling and measuring techniques for particles with known toxicity in selected workplaces. Despite the lack of specific NP exposure limit values, exposure metrics, appropriate to nanoaerosols, are discussed in the Technical Report ISO/TR 27628:2007 with the aim to enable occupational hygienists to characterize and monitor nanoaerosols in workplaces. Moreover, NIOSH has developed the Document Approaches to Safe Nanotechnology (intended to be an information exchange with NIOSH) in order to address current and future research needs to understanding the potential risks that nanotechnology may have to workers.

The influence of temperature calibration on the OC-EC results from a dual-optics thermal carbon analyzer

NASA Astrophysics Data System (ADS)

Pavlovic, J.; Kinsey, J. S.; Hays, M. D.

2014-09-01

Thermal-optical analysis (TOA) is a widely used technique that fractionates carbonaceous aerosol particles into organic and elemental carbon (OC and EC), or carbonate. Thermal sub-fractions of evolved OC and EC are also used for source identification and apportionment; thus, oven temperature accuracy during TOA analysis is essential. Evidence now indicates that the "actual" sample (filter) temperature and the temperature measured by the built-in oven thermocouple (or set-point temperature) can differ by as much as 50 °C. This difference can affect the OC-EC split point selection and consequently the OC and EC fraction and sub-fraction concentrations being reported, depending on the sample composition and in-use TOA method and instrument. The present study systematically investigates the influence of an oven temperature calibration procedure for TOA. A dual-optical carbon analyzer that simultaneously measures transmission and reflectance (TOT and TOR) is used, functioning under the conditions of both the National Institute of Occupational Safety and Health Method 5040 (NIOSH) and Interagency Monitoring of Protected Visual Environment (IMPROVE) protocols. The application of the oven calibration procedure to our dual-optics instrument significantly changed NIOSH 5040 carbon fractions (OC and EC) and the IMPROVE OC fraction. In addition, the well-known OC-EC split difference between NIOSH and IMPROVE methods is even further perturbed following the instrument calibration. Further study is needed to determine if the widespread application of this oven temperature calibration procedure will indeed improve accuracy and our ability to compare among carbonaceous aerosol studies that use TOA.

Atmospheric aerosol source identification and estimates of source contributions to air pollution in Dundee, UK

NASA Astrophysics Data System (ADS)

Qin, Y.; Oduyemi, K.

Anthropogenic aerosol (PM 10) emission sources sampled at an air quality monitoring station in Dundee have been analysed. However, the information on local natural aerosol emission sources was unavailable. A method that combines receptor model and atmospheric dispersion model was used to identify aerosol sources and estimate source contributions to air pollution. The receptor model identified five sources. These are aged marine aerosol source with some chlorine replaced by sulphate, secondary aerosol source of ammonium sulphate, secondary aerosol source of ammonium nitrate, soil and construction dust source, and incinerator and fuel oil burning emission source. For the vehicle emission source, which has been comprehensively described in the atmospheric emission inventory but cannot be identified by the receptor model, an atmospheric dispersion model was used to estimate its contributions. In Dundee, a significant percentage, 67.5%, of the aerosol mass sampled at the study station could be attributed to the six sources named above.

Gaseous and particulate emissions from prescribed burning in Georgia.

PubMed

Lee, Sangil; Baumann, Karsten; Schauer, James J; Sheesley, Rebecca J; Naeher, Luke P; Meinardi, Simone; Blake, Donald R; Edgerton, Eric S; Russell, Armistead G; Clements, Mark

2005-12-01

Prescribed burning is a significant source of fine particulate matter (PM2.5) in the southeastern United States. However, limited data exist on the emission characteristics from this source. Various organic and inorganic compounds both in the gas and particle phase were measured in the emissions of prescribed burnings conducted at two pine-dominated forest areas in Georgia. The measurements of volatile organic compounds (VOCs) and PM2.5 allowed the determination of emission factors for the flaming and smoldering stages of prescribed burnings. The VOC emission factors from smoldering were distinctly higher than those from flaming except for ethene, ethyne, and organic nitrate compounds. VOC emission factors show that emissions of certain aromatic compounds and terpenes such as alpha and beta-pinenes, which are important precursors for secondary organic aerosol (SOA), are much higher from active prescribed burnings than from fireplace wood and laboratory open burning studies. Levoglucosan is the major particulate organic compound (POC) emitted for all these studies, though its emission relative to total organic carbon (mg/g OC) differs significantly. Furthermore, cholesterol, an important fingerprint for meat cooking, was observed only in our in situ study indicating a significant release from the soil and soil organisms during open burning. Source apportionment of ambient primary fine particulate OC measured at two urban receptor locations 20-25 km downwind yields 74 +/- 11% during and immediately after the burns using our new in situ profile. In comparison with the previous source profile from laboratory simulations, however, this OC contribution is on average 27 +/- 5% lower.

Chemical characterization and source apportionment of size-resolved particles in Hong Kong sub-urban area

NASA Astrophysics Data System (ADS)

Gao, Yuan; Lee, Shun-Cheng; Huang, Yu; Chow, Judith C.; Watson, John G.

2016-03-01

Size-resolved particulate matter (PM) samples were collected with a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) at a sub-urban site (Tung Chung) in Hong Kong for four non-consecutive months representing four seasons from 2011 to 2012. Major chemical components were water-soluble anions (i.e., Cl-, NO3-, and SO42 -), cations (i.e., NH4+, Na+, K+, and Ca2 +), organic and elemental carbon and elements. Both chemical mass closure and positive matrix factorization (PMF) were employed to understand the chemical composition, resolve particle size modes, and evaluate the PM sources. Tri-modal size distributions were found for PM mass and major chemical components (e.g., SO42 -, NH4+, and OC). Mass median aerodynamic diameters (MMADs) with similar standard deviations (1.32 < σ < 1.42) were 0.4, 0.7 and 3.8 μm, consistent with condensation, droplet and coarse modes. A bi-modal distribution peaking at condensation and droplet modes was found for EC, with a single mode peaking at 3.8 μm for Cl-. Besides secondary SO42 -, carbonaceous aerosol dominated the condensation mode with 27% by engine exhaust and 18-19% each by residual oil combustion (shipping) and coal/biomass burning. Secondary SO42 - is also the most dominant component in the droplet mode, accounting for 23% of PM mass, followed by an industrial source (19%). Engine exhaust, secondary NO3-, and sea salt each accounted for 13-15% of PM mass. Sea salt and soil are the dominated sources in the coarse mode, accounting for 80% of coarse mass.

Source apportionment of PAH in Hamilton Harbour suspended sediments: comparison of two factor analysis methods.

PubMed

Sofowote, Uwayemi M; McCarry, Brian E; Marvin, Christopher H

2008-08-15

A total of 26 suspended sediment samples collected over a 5-year period in Hamilton Harbour, Ontario, Canada and surrounding creeks were analyzed for a suite of polycyclic aromatic hydrocarbons and sulfur heterocycles. Hamilton Harbour sediments contain relatively high levels of polycyclic aromatic compounds and heavy metals due to emissions from industrial and mobile sources. Two receptor modeling methods using factor analyses were compared to determine the profiles and relative contributions of pollution sources to the harbor; these methods are principal component analyses (PCA) with multiple linear regression analysis (MLR) and positive matrix factorization (PMF). Both methods identified four factors and gave excellent correlation coefficients between predicted and measured levels of 25 aromatic compounds; both methods predicted similar contributions from coal tar/coal combustion sources to the harbor (19 and 26%, respectively). One PCA factor was identified as contributions from vehicular emissions (61%); PMF was able to differentiate vehicular emissions into two factors, one attributed to gasoline emissions sources (28%) and the other to diesel emissions sources (24%). Overall, PMF afforded better source identification than PCA with MLR. This work constitutes one of the few examples of the application of PMF to the source apportionment of sediments; the addition of sulfur heterocycles to the analyte list greatly aided in the source identification process.

Identification of biased sectors in emission data using a combination of chemical transport model and receptor model

NASA Astrophysics Data System (ADS)

Uranishi, Katsushige; Ikemori, Fumikazu; Nakatsubo, Ryohei; Shimadera, Hikari; Kondo, Akira; Kikutani, Yuki; Asano, Katsuyoshi; Sugata, Seiji

2017-10-01

This study presented a comparison approach with multiple source apportionment methods to identify which sectors of emission data have large biases. The source apportionment methods for the comparison approach included both receptor and chemical transport models, which are widely used to quantify the impacts of emission sources on fine particulate matter of less than 2.5 μm in diameter (PM2.5). We used daily chemical component concentration data in the year 2013, including data for water-soluble ions, elements, and carbonaceous species of PM2.5 at 11 sites in the Kinki-Tokai district in Japan in order to apply the Positive Matrix Factorization (PMF) model for the source apportionment. Seven PMF factors of PM2.5 were identified with the temporal and spatial variation patterns and also retained features of the sites. These factors comprised two types of secondary sulfate, road transportation, heavy oil combustion by ships, biomass burning, secondary nitrate, and soil and industrial dust, accounting for 46%, 17%, 7%, 14%, 13%, and 3% of the PM2.5, respectively. The multiple-site data enabled a comprehensive identification of the PM2.5 sources. For the same period, source contributions were estimated by air quality simulations using the Community Multiscale Air Quality model (CMAQ) with the brute-force method (BFM) for four source categories. Both models provided consistent results for the following three of the four source categories: secondary sulfates, road transportation, and heavy oil combustion sources. For these three target categories, the models' agreement was supported by the small differences and high correlations between the CMAQ/BFM- and PMF-estimated source contributions to the concentrations of PM2.5, SO42-, and EC. In contrast, contributions of the biomass burning sources apportioned by CMAQ/BFM were much lower than and little correlated with those captured by the PMF model, indicating large uncertainties in the biomass burning emissions used in the CMAQ simulations. Thus, this comparison approach using the two antithetical models enables us to identify which sectors of emission data have large biases for improvement of future air quality simulations.

Positive matrix factorization as source apportionment of soil lead and cadmium around a battery plant (Changxing County, China).

PubMed

Xue, Jian-long; Zhi, Yu-you; Yang, Li-ping; Shi, Jia-chun; Zeng, Ling-zao; Wu, Lao-sheng

2014-06-01

Chemical compositions of soil samples are multivariate in nature and provide datasets suitable for the application of multivariate factor analytical techniques. One of the analytical techniques, the positive matrix factorization (PMF), uses a weighted least square by fitting the data matrix to determine the weights of the sources based on the error estimates of each data point. In this research, PMF was employed to apportion the sources of heavy metals in 104 soil samples taken within a 1-km radius of a lead battery plant contaminated site in Changxing County, Zhejiang Province, China. The site is heavily contaminated with high concentrations of lead (Pb) and cadmium (Cd). PMF successfully partitioned the variances into sources related to soil background, agronomic practices, and the lead battery plants combined with a geostatistical approach. It was estimated that the lead battery plants and the agronomic practices contributed 55.37 and 29.28%, respectively, for soil Pb of the total source. Soil Cd mainly came from the lead battery plants (65.92%), followed by the agronomic practices (21.65%), and soil parent materials (12.43%). This research indicates that PMF combined with geostatistics is a useful tool for source identification and apportionment.

Mineral dust transport and deposition to Antarctica: a climate model perspective

NASA Astrophysics Data System (ADS)

Albani, S.; Mahowald, N. M.; Maggi, V.; Delmonte, B.

2009-04-01

Windblown mineral dust is a useful proxy for paleoclimates. Its life cycle is determined by climate conditions in the source areas, and following the hydrological cycle, and the intensity and dynamics of the atmospheric circulation. In addition aeolian dust itself is an active component of the climate system, influencing the radiative balance of the atmosphere through its interaction with incoming solar radiation and outgoing planetary radiation. The mineral aerosols also have indirect effects on climate, and are linked to interactions with cloud microphysics and atmospheric chemistry as well as to dust's role of carrier of iron and other elements that constitute limitating nutrients for phytoplancton to remote ocean areas. We use climate model (CCSM) simulations that include a scheme for dust mobilization, transport and deposition in order to describe the evolution of dust deposition in some Antarctic ice cores sites where mineral dust records are available. Our focus is to determine the source apportionment for dust deposited to Antarctica under current and Last Glacial Maximum climate conditions, as well as to give an insight in the spatial features of transport patterns. The understanding of spatial and temporal representativeness of an ice core record is crucial to determine its value as a proxy of past climates and a necessary step in order to produce a global picture of how the dust component of the climate system has changed through time.

Urban air-quality assessment and source apportionment studies for Bhubaneshwar, Odisha

NASA Astrophysics Data System (ADS)

Mahapatra, Parth Sarathi; Ray, Sanak; Das, Namrata; Mohanty, Ayusman; Ramulu, T. S.; Das, Trupti; Chaudhury, G. Roy; Das, S. N.

2013-04-01

Acid- and water-soluble component of suspended particulate matter was studied from January 2009 to December 2009 at Bhubaneshwar, an urban coastal location of eastern India, by high-volume sampler, environmental dust monitor using GRIMM®, and scanning electron microscope and energy dispersive X-ray spectrometer. The water-soluble components accounted for 30-45 % of the total suspended particulate matter, and the major elements were observed to be ammonium and nitrate as the cationic and anionic species, respectively. The acid-soluble component like copper, nickel, cobalt, iron, and lead accounted for 5-15 % of the total particulate matter concentration. The composition of particulate matter shows a clear seasonal variation in relation to wind speed, wind direction, and trajectories of the air mass movement. The GRIMM spectrometer analysis shows higher concentration of fine particulate matter. Source apportionment and enrichment factor analysis indicated that except sodium and chloride, all other elements have emerged from different sources such as crustal as well as anthropogenic.

Source apportionment of population representative samples of PM(2.5) in three European cities using structural equation modelling.

PubMed

Ilacqua, Vito; Hänninen, Otto; Saarela, Kristina; Katsouyanni, Klea; Künzli, Nino; Jantunen, Matti

2007-10-01

Apportionment of urban particulate matter (PM) to sources is central for air quality management and efficient reduction of the substantial public health risks associated with fine particles (PM(2.5)). Traffic is an important source combustion particles, but also a significant source of resuspended particles that chemically resemble Earth's crust and that are not affected by development of cleaner motor technologies. A substantial fraction of urban ambient PM originates from long-range transport outside the immediate urban environment including secondary particles formed from gaseous emissions of mainly sulphur, nitrogen oxides and ammonia. Most source apportionment studies are based on small number of fixed monitoring sites and capture well population exposures to regional and long-range transported particles. However, concentrations from local sources are very unevenly distributed and the results from such studies are therefore poorly representative of the actual exposures. The current study uses PM(2.5) data observed at population based random sampled residential locations in Athens, Basle and Helsinki with 17 elemental constituents, selected VOCs (xylenes, trimethylbenzenes, nonane and benzene) and light absorbance (black smoke). The major sources identified across the three cities included crustal, salt, long-range transported inorganic and traffic sources. Traffic was associated separately with source categories with crustal (especially Athens and Helsinki) and long-range transported chemical composition (all cities). Remarkably high fractions of the variability of elemental (R(2)>0.6 except for Ca in Basle 0.38) and chemical concentrations (R(2)>0.5 except benzene in Basle 0.22 and nonane in Athens 0.39) are explained by the source factors of an SEM model. The RAINS model that is currently used as the main tool in developing European air quality management policies seems to capture the local urban fraction (the city delta term) quite well, but underestimates crustal particle levels in the three cities of the current study. Utilizing structural equation modelling parallel with traditional principal component analysis (PCA) provides an objective method to determine the number of factors to be retained in a model and allows for formal hypotheses testing.

A stable isotope model for combined source apportionment and degradation quantification of environmental pollutants

NASA Astrophysics Data System (ADS)

Lutz, Stefanie; Van Breukelen, Boris

2014-05-01

Natural attenuation can represent a complementary or alternative approach to engineered remediation of polluted sites. In this context, compound specific stable isotope analysis (CSIA) has proven a useful tool, as it can provide evidence of natural attenuation and assess the extent of in-situ degradation based on changes in isotope ratios of pollutants. Moreover, CSIA can allow for source identification and apportionment, which might help to identify major emission sources in complex contamination scenarios. However, degradation and mixing processes in aquifers can lead to changes in isotopic compositions, such that their simultaneous occurrence might complicate combined source apportionment (SA) and assessment of the extent of degradation (ED). We developed a mathematical model (stable isotope sources and sinks model; SISS model) based on the linear stable isotope mixing model and the Rayleigh equation that allows for simultaneous SA and quantification of the ED in a scenario of two emission sources and degradation via one reaction pathway. It was shown that the SISS model with CSIA of at least two elements contained in the pollutant (e.g., C and H in benzene) allows for unequivocal SA even in the presence of degradation-induced isotope fractionation. In addition, the model enables precise quantification of the ED provided degradation follows instantaneous mixing of two sources. If mixing occurs after two sources have degraded separately, the model can still yield a conservative estimate of the overall extent of degradation. The SISS model was validated against virtual data from a two-dimensional reactive transport model. The model results for SA and ED were in good agreement with the simulation results. The application of the SISS model to field data of benzene contamination was, however, challenged by large uncertainties in measured isotope data. Nonetheless, the use of the SISS model provided a better insight into the interplay of mixing and degradation processes at the field site, as it revealed the prevailing contribution of one emission source and a low overall ED. The model can be extended to a larger number of sources and sinks. It may aid in forensics and natural attenuation assessment of soil, groundwater, surface water, or atmospheric pollution.

SOURCE APPORTIONMENT OF PM2.5 AT AN URBAN IMPROVE SITE IN SEATTLE, WA

EPA Science Inventory

The multivariate receptor models Positive Matrix Factorization (PMF) and Unmix were used along with EPA's Chemical Mass Balance model to deduce the sources of PM2.5 at a centrally located urban site in Seattle, Washington. A total of 289 filter samples were obtained with an IM...

77 FR 11798 - Approval and Promulgation of Air Quality Implementation Plans; Rhode Island; Regional Haze

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-28

...; and Lye Brook Wilderness Area in Vermont. Through source apportionment modeling, MANE-VU assisted... sources and activities which are located across a broad geographic area and emit fine particles and their...., sulfates, nitrates, organic carbon, elemental carbon, and soil dust), which also impair visibility by...

ENVIRONMENTAL APPLICATIONS OF NOVEL INSTRUMENTATION FOR MEASUREMENT OF LEAD ISOTOPE RATIOS IN ATMOSPHERIC POLLUTION SOURCE APPORTIONMENT STUDIES

EPA Science Inventory

In spite of the reduced flux of lead to the atmosphere from the combustion of leaded gasoline, anthropogenic sources still dominate the supply of lead to the atmosphere and the environment. Emissions from coal and oil combustion, industrial processes, and municipal incineration w...

Levels and source apportionment of children's lead exposure: could urinary lead be used to identify the levels and sources of children's lead pollution?

PubMed

Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

2015-04-01

As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Apportionment of the sources of high fine particulate matter concentration events in a developing aerotropolis in Taoyuan, Taiwan.

PubMed

Chuang, Ming-Tung; Chen, Yu-Chieh; Lee, Chung-Te; Cheng, Chung-Hao; Tsai, Yu-Jen; Chang, Shih-Yu; Su, Zhen-Sen

2016-07-01

To investigate the characteristics and contributions of the sources of fine particulate matter with a size of up to 2.5 μm (PM2.5) during the period when pollution events could easily occur in Taoyuan aerotropolis, Taiwan, this study conducted sampling at three-day intervals from September 2014 to January 2015. Based on the mass concentration of PM2.5, the sampling days were classified into high PM2.5 concentration event days (PM2.5>35 μg m(-3)) and non-event days (PM2.5<35 μg m(-3)). In addition, the chemical species, including water-soluble inorganic ions, carbonaceous components, and metal elements, were analyzed. The sources of pollution and their contributions were estimated using the positive matrix factorization (PMF) model. Furthermore, the effect of the weather type on the measurement results was also explored based on wind field conditions. The mass fractions of Cl(-) and NO3(-) increased when a high PM2.5 concentration event occurred, and they were also higher under local emitted conditions than under long range transported conditions, indicating that secondary nitrate aerosols were the major increasing local species that caused high PM2.5 concentration events. Seven sources of pollution could be distinguished using the PMF model on the basis of the characteristics of the species. Industrial emissions, coal combustion/urban waste incineration, and local emissions from diesel/gasoline vehicles were the main sources that contributed to pollution on high PM2.5 concentration event days. In order to reduction of high PM2.5 concentration events, the control of diesel and gasoline vehicle emission is important and should be given priority. Copyright © 2016 Elsevier Ltd. All rights reserved.

Understanding the Impacts of Land Uses on the Source Apportionment of Atmospheric Contamination By Polycyclic Aromatic Hydrocarbons throughout a Small State in the Northeast United States

NASA Astrophysics Data System (ADS)

Schifman, L. A.; Boving, T. B.

2014-12-01

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous contaminants that enter the environment through combustion processes and are often found in higher concentration of urban areas. However, once released, these compounds can travel long distances via transport through the atmosphere and can be deposited on the landscape far away from their original source. This PAH deposition pattern can slowly lead to the diffuse contamination of whole landscapes. Since most of the air masses entering the northeastern United States originate from the Midwest where coal burning power plants are plentiful, several atmospheric pollutants are introduced to the region in addition to local sources. Here, atmospheric deposition of PAHs in six different locations throughout Rhode Island was measured using passive bulk-deposition samplers for 3 years. The data were analyzed statistically by principal component analysis and factor analysis to identify the source of contamination and respective apportionment. The data clearly show that an urban-to- rural gradient exists where deposition rates are significantly higher in urban areas (up to 12325 ng/d m2 ∑PAH) compared to rural areas (as low as 11 ng/d m2 ∑PAH) and also follow seasonal trends that show higher deposition rates in the fall and winter compared to the summer and spring time. Further, based on PAH source apportionment ratios, contamination origins differ spatially. For example, fossil fuel, coal, and vehicle combustion is present in all samples; however fossil fuel combustion is dominant in urban samples. In Rural areas biomass combustion is much more prevalent and is not as greatly represented in urban or suburban areas. Therefore, even in a small state such as Rhode Island airborne PAH contamination can be fingerprinted readily for different sampling areas, indicating that distant emission sources have a widespread impact on regional air quality.

Space-time quantitative source apportionment of soil heavy metal concentration increments.

PubMed

Yang, Yong; Christakos, George; Guo, Mingwu; Xiao, Lu; Huang, Wei

2017-04-01

Assessing the space-time trends and detecting the sources of heavy metal accumulation in soils have important consequences in the prevention and treatment of soil heavy metal pollution. In this study, we collected soil samples in the eastern part of the Qingshan district, Wuhan city, Hubei Province, China, during the period 2010-2014. The Cd, Cu, Pb and Zn concentrations in soils exhibited a significant accumulation during 2010-2014. The spatiotemporal Kriging technique, based on a quantitative characterization of soil heavy metal concentration variations in terms of non-separable variogram models, was employed to estimate the spatiotemporal soil heavy metal distribution in the study region. Our findings showed that the Cd, Cu, and Zn concentrations have an obvious incremental tendency from the southwestern to the central part of the study region. However, the Pb concentrations exhibited an obvious tendency from the northern part to the central part of the region. Then, spatial overlay analysis was used to obtain absolute and relative concentration increments of adjacent 1- or 5-year periods during 2010-2014. The spatial distribution of soil heavy metal concentration increments showed that the larger increments occurred in the center of the study region. Lastly, the principal component analysis combined with the multiple linear regression method were employed to quantify the source apportionment of the soil heavy metal concentration increments in the region. Our results led to the conclusion that the sources of soil heavy metal concentration increments should be ascribed to industry, agriculture and traffic. In particular, 82.5% of soil heavy metal concentration increment during 2010-2014 was ascribed to industrial/agricultural activities sources. Using STK and SOA to obtain the spatial distribution of heavy metal concentration increments in soils. Using PCA-MLR to quantify the source apportionment of soil heavy metal concentration increments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial-temporal Variations and Source Apportionment of typical Heavy Metals in Beijing-Tianjin-Hebei (BTH) region of China Based on Localized Air Pollutants Emission Inventory and WRF-CMAQ modelling

NASA Astrophysics Data System (ADS)

Tian, H.; Liu, S.; Zhu, C.; Liu, H.; Wu, B.

2017-12-01

Abstract: Anthropogenic atmospheric emissions of air pollutants have caused worldwide concerns due to their adverse effects on human health and the ecosystem. By determining the best available emission factors for varied source categories, we established the comprehensive atmospheric emission inventories of hazardous air pollutants including 12 typical toxic heavy metals (Hg, As, Se, Pb, Cd, Cr, Ni, Sb, Mn, Co, Cu, and Zn) from primary anthropogenic activities in Beijing-Tianjin-Hebei (BTH) region of China for the period of 2012 for the first time. The annual emissions of these pollutants were allocated at a high spatial resolution of 9km × 9km grid with ArcGIS methodology and surrogate indexes, such as regional population and gross domestic product (GDP). Notably, the total heavy metal emissions from this region represented about 10.9% of the Chinese national total emissions. The areas with high emissions of heavy metals were mainly concentrated in Tangshan, Shijiazhuang, Handan and Tianjin. Further, WRF-CMAQ modeling system were applied to simulate the regional concentration of heavy metals to explore their spatial-temporal variations, and the source apportionment of these heavy metals in BTH region was performed using the Brute-Force method. Finally, integrated countermeasures were proposed to minimize the final air pollutants discharge on account of the current and future demand of energy-saving and pollution reduction in China. Keywords: heavy metals; particulate matter; emission inventory; CMAQ model; source apportionment Acknowledgment. This work was funded by the National Natural Science Foundation of China (21377012 and 21177012) and the Trail Special Program of Research on the Cause and Control Technology of Air Pollution under the National Key Research and Development Plan of China (2016YFC0201501).

Fugitive Dust Emissions: Development of a Real-time Monitor

DTIC Science & Technology

2011-10-01

the mechanical disturbance of soils which injects particles into the air. Common sources of FD include vehicles driving on unpaved roads...agricultural tilling, and heavy construction operations. For these sources the dust-generation process is caused by two basic physical phenomena...visibility, source apportionment , etc. The PM10 standard set by the U.S. Environmental Protection Agency in 1987 is an example of size-selective