Science.gov

Sample records for aerosol precursor emissions

  1. Regional and seasonal radiative forcing by perturbations to aerosol and ozone precursor emissions

    NASA Astrophysics Data System (ADS)

    Bellouin, Nicolas; Baker, Laura; Hodnebrog, Øivind; Olivié, Dirk; Cherian, Ribu; Macintosh, Claire; Samset, Bjørn; Esteve, Anna; Aamaas, Borgar; Quaas, Johannes; Myhre, Gunnar

    2016-11-01

    Predictions of temperature and precipitation responses to changes in the anthropogenic emissions of climate forcers require the quantification of the radiative forcing exerted by those changes. This task is particularly difficult for near-term climate forcers like aerosols, methane, and ozone precursors because their short atmospheric lifetimes cause regionally and temporally inhomogeneous radiative forcings. This study quantifies specific radiative forcing, defined as the radiative forcing per unit change in mass emitted, for eight near-term climate forcers as a function of their source regions and the season of emission by using dedicated simulations by four general circulation and chemistry-transport models. Although differences in the representation of atmospheric chemistry and radiative processes in different models impede the creation of a uniform dataset, four distinct findings can be highlighted. Firstly, specific radiative forcing for sulfur dioxide and organic carbon are stronger when aerosol-cloud interactions are taken into account. Secondly, there is a lack of agreement on the sign of the specific radiative forcing of volatile organic compound perturbations, suggesting they are better avoided in climate mitigation strategies. Thirdly, the strong seasonalities of the specific radiative forcing of most forcers allow strategies to minimise positive radiative forcing based on the timing of emissions. Finally, European and shipping emissions exert stronger aerosol specific radiative forcings compared to East Asia where the baseline is more polluted. This study can therefore form the basis for further refining climate mitigation options based on regional and seasonal controls on emissions. For example, reducing summertime emissions of black carbon and wintertime emissions of sulfur dioxide in the more polluted regions is a possible way to improve air quality without weakening the negative radiative forcing of aerosols.

  2. Effect of bark beetle infestation on secondary organic aerosol precursor emissions.

    PubMed

    Amin, Hardik; Atkins, P Tyson; Russo, Rachel S; Brown, Aaron W; Sive, Barkley; Hallar, A Gannet; Huff Hartz, Kara E

    2012-06-05

    Bark beetles are a potentially destructive force in forest ecosystems; however, it is not known how insect attacks affect the atmosphere. The emissions of volatile organic compounds (VOCs) were sampled i.) from bark beetle infested and healthy lodgepole pine (Pinus contorta var. latifolia) trees and ii.) from sites with and without active mountain pine beetle infestation. The emissions from the trunk and the canopy were collected via sorbent traps. After collection, the sorbent traps were extracted with hexane, and the extracts were separated and detected using gas chromatography/mass spectroscopy. Canister samples were also collected and analyzed by a multicolumn gas chromatographic system. The samples from bark beetle infested lodgepole pine trees suggest a 5- to 20-fold enhancement in total VOCs emissions. Furthermore, increases in the β-phellandrene emissions correlated with bark beetle infestation. A shift in the type and the quantity of VOC emissions can be used to identify bark beetle infestation but, more importantly, can lead to increases in secondary organic aerosol from these forests as potent SOA precursors are produced.

  3. Projected response of East Asian summer monsoon system to future reductions in emissions of anthropogenic aerosols and their precursors

    NASA Astrophysics Data System (ADS)

    Wang, Zhili; Zhang, Hua; Zhang, Xiaoye

    2016-09-01

    The response of the East Asian summer monsoon (EASM) system to reductions in emissions of anthropogenic aerosols and their precursors at the end of the twenty-first century projected by Representative Concentration Pathway 4.5 is studied using an aerosol-climate model with aerosol direct, semi-direct, and indirect effects included. Our results show that the global annual mean aerosol effective radiative forcing at the top of the atmosphere (TOA) is +1.45 W m-2 from 2000 to 2100. The summer mean net all-sky shortwave fluxes averaged over the East Asian monsoon region (EAMR) at the TOA and surface increased by +3.9 and +4.0 W m-2, respectively, due to the reductions of aerosols in 2100 relative to 2000. Changes in radiations affect local thermodynamic and dynamic processes and the hydrological cycle. The summer mean surface temperature and pressure averaged over the EAMR are shown to increase by 1.7 K and decreased by 0.3 hPa, respectively, due to the reduced aerosols. The magnitudes of these changes are larger over land than ocean, causing a marked increase in the contrast of land-sea surface temperature and pressure in the EAMR, thus strengthening the EASM. The summer mean southwest and south winds at 850 hPa are enhanced over eastern and southern China and the surrounding oceans, and the East Asian subtropical jet shifted northward due to the decreases of aerosols. These factors also indicate enhanced EASM circulation, which in turn causes a 10 % increase in summer mean precipitation averaged over the EAMR.

  4. Plant and Soil Emissions of Amines and Amino Acids: A Source of Secondary Aerosol Precursors

    NASA Astrophysics Data System (ADS)

    Jackson, M. L.; Doskey, P. V.; Pypker, T. G.

    2011-12-01

    Ammonia (NH3) is the most abundant alkaline gas in the atmosphere and forms secondary aerosol by neutralizing sulfuric and nitric acids that are released during combustion of fossil fuels. Ammonia is primarily emitted by cropping and livestock operations. However, C2 and C3 amines (pKb 3.3-3.4), which are stronger bases than NH3 (pKb 4.7) have been observed in nuclei mode aerosol that is the precursor to secondary aerosol. Mixtures of amines and amino acids have been identified in diverse environments in aerosol, fog water, cloud water, the soluble fraction of precipitation, and in dew. Glycine (pKb 4.2), serine (pKb 4.8) and alanine (pKb 3.7 and 4.1 for the D and L forms, respectively) are typically the most abundant species. The only reported values of gas-phase glycine, serine and alanine were in marine air and ranged from 6-14 pptv. The origin of atmospheric amines and amino acids has not been fully identified, although sources are likely similar to NH3. Nitrate assimilation in plants forms glycine, serine, and L-alanine, while D-alanine is present in bacterial cell walls. Glycine is converted to serine during C3 plant photorespiration, producing CO2 and NH3. Bacteria metabolize glycine and alanine to methylamine and ethylamine via decarboxylation. Likely sources of amino acids are plants and bacteria, thus concentrations near continental sources are likely greater than those measured in marine air. The overall goal of the research is to examine seasonal variations and relationships between the exchange of CO2, NH3, amines, and amino acids with a corn/soybean rotation in the Midwest Corn Belt. The study presents gaseous profiles of organic amine compounds from various species of vegetation using a mist chamber trapping technique and analysis of the derivatized species by high pressure liquid chromatography with fluorescence detection. Amino acid and amine profiles were obtained for red oak (Quercus rubra), sugar maple (Acer saccharinum), white pine (Pinus

  5. Design of Aerosol Coating Reactors: Precursor Injection

    PubMed Central

    Buesser, Beat; Pratsinis, Sotiris E.

    2013-01-01

    Particles are coated with thin shells to facilitate their processing and incorporation into liquid or solid matrixes without altering core particle properties (coloristic, magnetic, etc.). Here, computational fluid and particle dynamics are combined to investigate the geometry of an aerosol reactor for continuous coating of freshly-made titanium dioxide core nanoparticles with nanothin silica shells by injection of hexamethyldisiloxane (HMDSO) vapor downstream of TiO2 particle formation. The focus is on the influence of HMDSO vapor jet number and direction in terms of azimuth and inclination jet angles on process temperature and coated particle characteristics (shell thickness and fraction of uncoated particles). Rapid and homogeneous mixing of core particle aerosol and coating precursor vapor facilitates synthesis of core-shell nanoparticles with uniform shell thickness and high coating efficiency (minimal uncoated core and free coating particles). PMID:23658471

  6. Multi-instrument comparison and compilation of non-methane organic gas emissions from biomass burning and implications for smoke-derived secondary organic aerosol precursors

    NASA Astrophysics Data System (ADS)

    Hatch, Lindsay E.; Yokelson, Robert J.; Stockwell, Chelsea E.; Veres, Patrick R.; Simpson, Isobel J.; Blake, Donald R.; Orlando, John J.; Barsanti, Kelley C.

    2017-01-01

    Multiple trace-gas instruments were deployed during the fourth Fire Lab at Missoula Experiment (FLAME-4), including the first application of proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS) and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS) for laboratory biomass burning (BB) measurements. Open-path Fourier transform infrared spectroscopy (OP-FTIR) was also deployed, as well as whole-air sampling (WAS) with one-dimensional gas chromatography-mass spectrometry (GC-MS) analysis. This combination of instruments provided an unprecedented level of detection and chemical speciation. The chemical composition and emission factors (EFs) determined by these four analytical techniques were compared for four representative fuels. The results demonstrate that the instruments are highly complementary, with each covering some unique and important ranges of compositional space, thus demonstrating the need for multi-instrument approaches to adequately characterize BB smoke emissions. Emission factors for overlapping compounds generally compared within experimental uncertainty, despite some outliers, including monoterpenes. Data from all measurements were synthesized into a single EF database that includes over 500 non-methane organic gases (NMOGs) to provide a comprehensive picture of speciated, gaseous BB emissions. The identified compounds were assessed as a function of volatility; 6-11 % of the total NMOG EF was associated with intermediate-volatility organic compounds (IVOCs). These atmospherically relevant compounds historically have been unresolved in BB smoke measurements and thus are largely missing from emission inventories. Additionally, the identified compounds were screened for published secondary organic aerosol (SOA) yields. Of the total reactive carbon (defined as EF scaled by the OH rate constant and carbon number of each compound) in the BB emissions, 55-77 % was associated with compounds for

  7. Atmospheric science: marine aerosols and iodine emissions.

    PubMed

    McFiggans, Gordon

    2005-02-10

    O'Dowd et al. describe the formation of marine aerosols from biogenic iodine and the growth of these aerosols into cloud-condensation nuclei (CCN). Based on chamber and modelling results, the authors suggest that biogenic organic iodine compounds emitted from macroalgae may be responsible for coastal particle bursts and that production of these compounds in the open ocean could increase CCN there too. It has since been shown that coastal particles are more likely to be produced from the photooxidation of molecular iodine. Moreover, I contend that open-ocean particle production and cloud enhancement do not result from emissions of organic iodine at atmospheric levels. For iodine particles to affect cloud properties over the remote ocean, an additional source of iodine is necessary as organic precursors cannot be responsible.

  8. Identification of significant precursor gases of secondary organic aerosols from residential wood combustion

    NASA Astrophysics Data System (ADS)

    Bruns, Emily A.; El Haddad, Imad; Slowik, Jay G.; Kilic, Dogushan; Klein, Felix; Baltensperger, Urs; Prévôt, André S. H.

    2016-06-01

    Organic gases undergoing conversion to form secondary organic aerosol (SOA) during atmospheric aging are largely unidentified, particularly in regions influenced by anthropogenic emissions. SOA dominates the atmospheric organic aerosol burden and this knowledge gap contributes to uncertainties in aerosol effects on climate and human health. Here we characterize primary and aged emissions from residential wood combustion using high resolution mass spectrometry to identify SOA precursors. We determine that SOA precursors traditionally included in models account for only ~3–27% of the observed SOA, whereas for the first time we explain ~84–116% of the SOA by inclusion of non-traditional precursors. Although hundreds of organic gases are emitted during wood combustion, SOA is dominated by the aging products of only 22 compounds. In some cases, oxidation products of phenol, naphthalene and benzene alone comprise up to ~80% of the observed SOA. Identifying the main precursors responsible for SOA formation enables improved model parameterizations and SOA mitigation strategies in regions impacted by residential wood combustion, more productive targets for ambient monitoring programs and future laboratories studies, and links between direct emissions and SOA impacts on climate and health in these regions.

  9. Identification of significant precursor gases of secondary organic aerosols from residential wood combustion

    PubMed Central

    Bruns, Emily A.; El Haddad, Imad; Slowik, Jay G.; Kilic, Dogushan; Klein, Felix; Baltensperger, Urs; Prévôt, André S. H.

    2016-01-01

    Organic gases undergoing conversion to form secondary organic aerosol (SOA) during atmospheric aging are largely unidentified, particularly in regions influenced by anthropogenic emissions. SOA dominates the atmospheric organic aerosol burden and this knowledge gap contributes to uncertainties in aerosol effects on climate and human health. Here we characterize primary and aged emissions from residential wood combustion using high resolution mass spectrometry to identify SOA precursors. We determine that SOA precursors traditionally included in models account for only ~3–27% of the observed SOA, whereas for the first time we explain ~84–116% of the SOA by inclusion of non-traditional precursors. Although hundreds of organic gases are emitted during wood combustion, SOA is dominated by the aging products of only 22 compounds. In some cases, oxidation products of phenol, naphthalene and benzene alone comprise up to ~80% of the observed SOA. Identifying the main precursors responsible for SOA formation enables improved model parameterizations and SOA mitigation strategies in regions impacted by residential wood combustion, more productive targets for ambient monitoring programs and future laboratories studies, and links between direct emissions and SOA impacts on climate and health in these regions. PMID:27312480

  10. Can scooter emissions dominate urban organic aerosol?

    NASA Astrophysics Data System (ADS)

    El Haddad, Imad; Platt, Stephen; Huang, Ru-Jin; Zardini, Alessandro; Clairotte, Micheal; Pieber, Simone; Pfaffenberger, Lisa; Fuller, Steve; Hellebust, Stig; Temime-Roussel, Brice; Slowik, Jay; Chirico, Roberto; Kalberer, Markus; Marchand, Nicolas; Dommen, Josef; Astorga, Covadonga; Baltensperger, Urs; Prevot, Andre

    2014-05-01

    In urban areas, where the health impact of pollutants increases due to higher population density, traffic is a major source of ambient organic aerosol (OA). A significant fraction of OA from traffic is secondary, produced via the reaction of exhaust volatile organic compounds (VOCs) with atmospheric oxidants. Secondary OA (SOA) has not been systematically assessed for different vehicles and driving conditions and thus its relative importance compared to directly emitted, primary OA (POA) is unknown, hindering the design of effective vehicle emissions regulations. 2-stroke (2S) scooters are inexpensive and convenient and as such a popular means of transportation globally, particularly in Asia. European regulations for scooters are less stringent than for other vehicles and thus primary particulate emissions and SOA precursor VOCs from 2S engines are estimated to be much higher. Assessing the effects of scooters on public health requires consideration of both POA, and SOA production. Here, we quantify POA emission factors and potential SOA EFs from 2S scooters, and the effect of using aromatic free fuel instead of standard gasoline thereon. During the tests, Euro 1 and Euro 2 2S scooters were run in idle or simulated low power conditions. Emissions from a Euro 2 2S scooter were also sampled during regulatory driving cycles on a chassis dynamometer. Vehicle exhaust was introduced into smog chambers, where POA emission and SOA production were quantified using a high-resolution time-of-flight aerosol mass spectrometer. A high resolution proton transfer time-of-flight mass spectrometer was used to investigate volatile organic compounds and a suite of instruments was utilized to quantify CO, CO2, O3, NOX and total hydrocarbons. We show that the oxidation of VOCs in the exhaust emissions of 2S scooters produce significant SOA, exceeding by up to an order of magnitude POA emissions. By monitoring the decay of VOC precursors, we show that SOA formation from 2S scooter

  11. Secondary aerosol production from agricultural gas precursors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies of air quality indicate that agricultural emissions may impact particulate mass concentrations through both primary and secondary processes. Increasing evidence from both laboratory and field work suggests that not only does ammonia produce secondary particulate matter, but some volatile org...

  12. Aerosols from overseas rival domestic emissions over North America.

    PubMed

    Yu, Hongbin; Remer, Lorraine A; Chin, Mian; Bian, Huisheng; Tan, Qian; Yuan, Tianle; Zhang, Yan

    2012-08-03

    Many types of aerosols have lifetimes long enough for their transcontinental transport, making them potentially important contributors to air quality and climate change in remote locations. We estimate that the mass of aerosols arriving at North American shores from overseas is comparable with the total mass of particulates emitted domestically. Curbing domestic emissions of particulates and precursor gases, therefore, is not sufficient to mitigate aerosol impacts in North America. The imported contribution is dominated by dust leaving Asia, not by combustion-generated particles. Thus, even a reduction of industrial emissions of the emerging economies of Asia could be overwhelmed by an increase of dust emissions due to changes in meteorological conditions and potential desertification.

  13. COS in the stratosphere. [sulfuric acid aerosol precursor

    NASA Technical Reports Server (NTRS)

    Inn, E. C. Y.; Vedder, J. F.; Tyson, B. J.; Ohara, D.

    1979-01-01

    Carbonyl sulfide (COS) has been detected in the stratosphere, and mixing ratio measurements are reported for altitudes of 15.2 to 31.2 km. A large volume, cryogenic sampling system mounted on board a U-2 aircraft has been used for lower stratosphere measurements and a balloon platform for measurement at 31.2 km. These observations and measurements strongly support the concept that stratospheric COS is an important precursor in the formation of sulfuric acid aerosols.

  14. Distributions and regional budgets of aerosols and their precursors simulated with the EMAC chemistry-climate model

    NASA Astrophysics Data System (ADS)

    Pozzer, A.; de Meij, A.; Pringle, K. J.; Tost, H.; Doering, U. M.; van Aardenne, J.; Lelieveld, J.

    2012-01-01

    The new global anthropogenic emission inventory (EDGAR-CIRCE) of gas and aerosol pollutants has been incorporated in the chemistry general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). A relatively high horizontal resolution simulation is performed for the years 2005-2008 to evaluate the capability of the model and the emissions to reproduce observed aerosol concentrations and aerosol optical depth (AOD) values. Model output is compared with observations from different measurement networks (CASTNET, EMEP and EANET) and AODs from remote sensing instruments (MODIS and MISR). A good spatial agreement of the distribution of sulfate and ammonium aerosol is found when compared to observations, while calculated nitrate aerosol concentrations show some discrepancies. The simulated temporal development of the inorganic aerosols is in line with measurements of sulfate and nitrate aerosol, while for ammonium aerosol some deviations from observations occur over the USA, due to the wrong temporal distribution of ammonia gas emissions. The calculated AODs agree well with the satellite observations in most regions, while negative biases are found for the equatorial area and in the dust outflow regions (i.e. Central Atlantic and Northern Indian Ocean), due to an underestimation of biomass burning and aeolian dust emissions, respectively. Aerosols and precursors budgets for five different regions (North America, Europe, East Asia, Central Africa and South America) are calculated. Over East-Asia most of the emitted aerosols (precursors) are also deposited within the region, while in North America and Europe transport plays a larger role. Further, it is shown that a simulation with monthly varying anthropogenic emissions typically improves the temporal correlation by 5-10% compared to one with constant annual emissions.

  15. Future aerosol emissions: a multi-model comparison

    SciTech Connect

    Smith, Steven J.; Rao, Shilpa; Riahi, Keywan; van Vuuren, Detlef P.; Calvin, Katherine V.; Kyle, Page

    2016-08-02

    This paper compares projections over the 21st century of SO2, BC, and OC emissions from three technologically detailed, long-term integrated assessment models. The character of the projections and the response of emissions due to a comprehensive climate policy are discussed. In a continuation of historical experience, aerosol and precursor emissions are increasingly decoupled from carbon dioxide emissions over the 21st century. Implementation of a comprehensive climate policy further reduces emissions, although there is significant variation in this response by sector and by model. Differences in model responses can be traced to specific characteristics of reference case end-use and supply-side technology deployment and emissions control assumptions, which are detailed by sector.

  16. Titan Aerosol Analogs from Aromatic Precursors: Comparisons to Cassini CIRS Observations in the Thermal Infrared

    NASA Technical Reports Server (NTRS)

    Trainer, Melissa G.; Sebree, Joshua A.; Anderson, Carrie M.; Loeffler, Mark J.

    2012-01-01

    Since Cassini's arrival at Titan, ppm levels of benzene (C6H6) as well as large positive ions, which may be polycyclic aromatic hydrocarbons (PAHs). have been detected in the atmosphere. Aromatic molecules. photolytically active in the ultraviolet, may be important in the formation of the organic aerosol comprising the Titan haze layer even when present at low mixing ratios. Yet there have not been laboratory simulations exploring the impact of these molecules as precursors to Titan's organic aerosol. Observations of Titan by the Cassini Composite Infrared Spectrometer (CIRS) in the far-infrared (far-IR) between 560 and 20/cm (approx. 18 to 500 microns) and in the mid-infrared (mid-IR) between 1500 and 600/cm (approx. 7 to 17 microns) have been used to infer the vertical variations of Titan's aerosol from the surface to an altitude of 300 km in the far-IR and between 150 and 350 km in the mid-IR. Titan's aerosol has several observed emission features which cannot be reproduced using currently available optical constants from laboratory-generated Titan aerosol analogs, including a broad far-IR feature centered approximately at 140/cm (71 microns).

  17. Aerosol Emission during Human Speech

    NASA Astrophysics Data System (ADS)

    Asadi, Sima; Ristenpart, William

    2016-11-01

    The traditional emphasis for airborne disease transmission has been on coughing and sneezing, which are dramatic expiratory events that yield easily visible droplets. Recent research suggests that normal speech can release even larger quantities of aerosols that are too small to see with the naked eye, but are nonetheless large enough to carry a variety of pathogens (e.g., influenza A). This observation raises an important question: what types of speech emit the most aerosols? Here we show that the concentration of aerosols emitted during healthy human speech is positively correlated with both the amplitude (loudness) and fundamental frequency (pitch) of the vocalization. Experimental measurements with an aerodynamic particle sizer (APS) indicate that speaking in a loud voice (95 decibels) yields up to fifty times more aerosols than in a quiet voice (75 decibels), and that sounds associated with certain phonemes (e.g., [a] or [o]) release more aerosols than others. We interpret these results in terms of the egressive airflow rate associated with each phoneme and the corresponding fundamental frequency, which is known to vary significantly with gender and age. The results suggest that individual speech patterns could affect the probability of airborne disease transmission.

  18. Distribution of sulfur aerosol precursors in the SPCZ released by continuous volcanic degassing at Ambrym, Vanuatu

    NASA Astrophysics Data System (ADS)

    Lefèvre, Jérôme; Menkes, Christophe; Bani, Philipson; Marchesiello, Patrick; Curci, Gabriele; Grell, Georg A.; Frouin, Robert

    2016-08-01

    The Melanesian Volcanic Arc (MVA) emits about 12 kT d- 1 of sulfur dioxide (SO2) to the atmosphere from continuous passive (non-explosive) volcanic degassing, which contributes 20% of the global SO2 emission from volcanoes. Here we assess, from up-to-date and long-term observations, the SO2 emission of the Ambrym volcano, one of the dominant volcanoes in the MVA, and we investigate its role as sulfate precursor on the regional distribution of aerosols, using both satellite observations and model results at 1° × 1° spatial resolution from WRF-Chem/GOCART. Without considering aerosol forcing on clouds, our model parameterizations for convection, vertical mixing and cloud properties provide a reliable chemical weather representation, making possible a cross-examination of model solution and observations. This preliminary work enables the identification of biases and limitations affecting both the model (missing sources) and satellite sensors and algorithms (for aerosol detection and classification) and leads to the implementation of improved transport and aerosol processes in the modeling system. On the one hand, the model confirms a 50% underestimation of SO2 emissions due to satellite swath sampling of the Ozone Monitoring Instrument (OMI), consistent with field studies. The OMI irregular sampling also produces a level of noise that impairs its monitoring capacity during short-term volcanic events. On the other hand, the model reveals a large sensitivity on aerosol composition and Aerosol Optical Depth (AOD) due to choices of both the source function in WRF-Chem and size parameters for sea-salt in FlexAOD, the post-processor used to compute offline the simulated AOD. We then proceed to diagnosing the role of SO2 volcanic emission in the regional aerosol composition. The model shows that both dynamics and cloud properties associated with the South Pacific Convergence Zone (SPCZ) have a large influence on the oxidation of SO2 and on the transport pathways of

  19. Aerosol Formation In The Free Troposphere: Aircraft and Laboratory Measurements of Ionic and Gaseous Aerosol Precursors

    NASA Astrophysics Data System (ADS)

    Arnold, F.

    Aerosol formation seems to be very efficient in the upper troposphere (UT) as in- dicated by the frequent presence of numerous very small and therefore very young aerosol particles. Aersosol formation proceeds via nucleation of supersaturated low volatility trace gases (LVG) involving either a homogeneous (HONU) or an ion- induced (INU) mechanism. LVG experience rapid removal by condenstation on prefer- ably pre-existing aerosol particles and therefore LVG must be formed locally in the UT by photochemical conversion of precursor gases. A prominent example is gaseous sulfuric acid which is formed from SO2. This SO2 originates at least in the northern hemisphere mostly from fossil fuel combustion at ground-level and to some part origi- nates also from jet aircraft cruising in the UT. Other conceivable LVG's are low volatil- ity organic compounds. After formation by nucleation new particles may experience condensational growth involving LVG. Alternatively new particles may experience scavenging by attachment to pre-existing larger particles. The LVG-concentration has a strong influence on the growth-rate of new particles and thereby on the possibil- ity for growth to the size of a cloud condensation nucleus. Unfortunately present knowledge on free tropospheric LVG is rather poor. Here will be reported free tropo- spheric aircraft-based measurements of ionic and gaseous aerosol-precursors. These include both measurements in the "background" FT as well as measurements in ex- haust plumes of jet aircraft cruising in the UT. Furthermore accompanying new labo- ratory investigations of INU and measurements behind aircraft jet engines at ground- level will also be adressed.

  20. Measurements of Biogenic and Anthropogenic Ozone and Aerosol Precursors during the SENEX (Southeast Nexus) Campaign 2013

    NASA Astrophysics Data System (ADS)

    Warneke, C.; Trainer, M.; De Gouw, J. A.

    2013-12-01

    Natural emissions of ozone and aerosol precursor gases such as isoprene and monoterpenes are the highest in the southeast of the U.S. and rival those found in tropical forests. In addition, anthropogenic emissions are significant in the Southeast and photochemistry is rapid. The southeast U.S. has not warmed like other parts of the U.S. in response to global climate change, and the temperature anomaly has been suggested to be related to aerosols derived from a combination of anthropogenic and biogenic precursors. The NOAA SENEX aircraft campaign took place in June-July 2013 in the southeast U.S. as part of the Southeast Atmosphere Study (SAS). The NOAA WP-3 aircraft conducted 20 research flights between May 27 and July 10, 2013 based out of Smyrna, TN. To investigate the combination of anthropogenic and biogenic emissions several flights were designed to follow the emissions of cities and power plants as they are transported over forested regions in the Southeast. For example, over-flights of Atlanta, Birmingham and Nashville were performed and the plumes were followed to the forested areas with high isoprene and monoterpene emissions. The same was done for several power plants such as EC Gaston, Scherer and Johnsonville. In the anthropogenic plumes, effects such as the modulation of the isoprene chemistry by high NOx and particle formation and growth were investigated. The same strategy was used for three nighttime flights over Atlanta, Birmingham and the New Madrid and White Bluff power plants. Flights over and downwind of St Lois and Indianapolis were used as a contrast in areas with smaller biogenic emissions. Other anthropogenic emissions sources that were investigated during SENEX included bio refineries, paper mills, coalmines, poultry and pork farming. Also biomass burning emissions were observed during one daytime and one nighttime flight. Another focus of the SENEX campaign was to determine the emissions of natural gas and oil production from the

  1. Far-IR Absorption Features of Titan Aerosol Analogs Produced from Aromatic Precursors

    NASA Astrophysics Data System (ADS)

    Sebree, Joshua; Trainer, M. G.; Anderson, C. M.; Loeffler, M. J.

    2012-10-01

    The arrival of the Cassini spacecraft in orbit around Saturn has led to the discovery of benzene (C6H6) at ppm levels, as well as large positive ions in Titan’s atmosphere, tentatively identified as polycyclic aromatic hydrocarbons (PAHs).[1] The presence of aromatic molecules, which are photolytically active in the ultraviolet, may be an important part of the formation of aerosol particles in Titan’s haze layers, even at these low concentrations. To date, there have been no laboratory experiments in the literature exploring this area of study. The analysis of data from the Composite Infrared Spectrometer (CIRS) on-board Cassini has recently uncovered a broad emission feature centered at 140 cm-1 in the far-IR that is unique to the aerosol layers of Titan’s atmosphere.[2] Current optical constants from laboratory-generated aerosol analogs have been unable to reproduce this feature.[3,4] From the broadness of this feature, we speculate that the emission is a blended composite of low-energy vibrations of large molecules such as PAHs and their nitrogen containing counterparts, polycyclic aromatic nitrogen heterocycles (PANHs). We hypothesize that the inclusion of trace amounts of aromatic precursors will aid in the production of these large structures in the laboratory-generated aerosols. In this study, we perform UV irradiation of several aromatic precursors, both with and without nitrogen heteroatoms, to understand their influence on the observable characteristics of the aerosol. Measured optical and chemical properties will be compared to those formed from CH4/N2 mixtures [5,6] as well as to those from Cassini observations. [1] Waite, J. H., et al. (2007) Science 316 870-875. [2] Anderson, C.M, et al. (2011) Icarus 212 762-778. [3] Khare, B.N., et al. (1984) Icarus 60 127-137. [4] Imanaka, H., et al. (2012) Icarus 218 247-261. [5] Trainer, M.G., et al. (2006) PNAS 103 18035-18042. [6] Trainer, M.G., et al. (2012) Astrobiology 12 315-326.

  2. Future Projections of Aerosol Optical Depth, Radiative Forcing, and Climate Response Due to Declining Aerosol Emissions in the Representative Concentration Pathways

    NASA Astrophysics Data System (ADS)

    Westervelt, D. M.; Mauzerall, D. L.; Horowitz, L. W.; Naik, V.

    2014-12-01

    It is widely expected that global emissions of atmospheric aerosols and their precursors will decrease strongly throughout the remainder of the 21st century, due to emission reduction policies enacted based on human health concerns. However, the resulting decrease in atmospheric aerosol burden will have unintended climate consequences. Since aerosols generally exert a net cooling influence on the climate, their removal will lead to an unmasking of global warming as well as other changes to the climate system. Aerosol and precursor global emissions decrease by as much as 80% by the year 2100, according to projections in four Representative Concentration Pathway (RCP) scenarios. We use the Geophysical Fluid Dynamics Laboratory Climate Model version 3 (GFDL CM3) to simulate future climate over the 21st century with and without aerosol emission changes projected by the RCPs in order to isolate the radiative forcing and climate response due to the aerosol reductions. We find that up to 1 W m-2 of radiative forcing may be unmasked globally by 2100 due to reductions in aerosol and precursor emissions, leading to average global temperature increases up to 1 K and global precipitation rate increases up to 0.09 mm d-1 (3%). Regionally and locally, climate impacts are much larger, as RCP8.5 projects a 2.1 K warming over China, Japan, and Korea due to reduced aerosol emissions. Our results highlight the importance of crafting emissions control policies with both climate and air pollution benefits in mind. The expected unmasking of additional global warming from aerosol reductions highlights the importance of robust greenhouse gas mitigation policies and may require more aggressive policies than anticipated.

  3. 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.

  4. The impact of residential combustion emissions on atmospheric aerosol, human health and climate

    NASA Astrophysics Data System (ADS)

    Butt, E. W.; Rap, A.; Schmidt, A.; Reddington, C.; Scott, C.; Pringle, K.; Woodhouse, M.; Spracklen, D. V.

    2015-12-01

    Combustion of fuels in the residential sector for cooking and heating, results in the emission of aerosol and aerosol precursors that effect air quality, human health and climate. Residential emissions are dominated by the combustion of solid fuels which are the primary energy source for nearly half the world's population. Despite this importance, residential emissions are poorly quantified, as are their impacts on air quality and climate. We used a global aerosol microphysics model to simulate the impact of residential emissions on atmospheric aerosol in the year 2000, and evaluated simulated concentrations against surface observations of aerosol mass and number. Residential emissions make the largest contributions to surface particulate matter (PM2.5) concentrations in East Asia, South Asia and Eastern Europe, matching regions of greatest emissions. We used concentration response functions to estimate a global annual excess adult (> 30 years of age) premature mortality due to residential emissions of between 113, 300 and 827, 000 when uncertainties in both residential emissions and health effects of PM2.5 were accounted for. Premature mortality was greatest in Asia, with China and India accounting for 50% of simulated global excess mortality. Using an offline radiative transfer model, we show that residential emissions exerted a global annual mean direct radiative effect of between -66 mW m-2 and +21 mW m-2, accounting for uncertainties in emissions flux and assumed ratio of carbonaceous and sulphur emissions. Residential emissions exerted a negative global annual mean first aerosol indirect effect of between -52 mW m-2 and -16 mW m-2, which was found to be sensitive to the assumed size distribution of carbonaceous emissions. Our results demonstrate that reducing residential combustion emissions would have substantial benefits for human health through reductions in ambient PM2.5 concentrations.

  5. Impacts of controlling biomass burning emissions on wintertime carbonaceous aerosol in Europe

    NASA Astrophysics Data System (ADS)

    Fountoukis, C.; Butler, T.; Lawrence, M. G.; Denier van der Gon, H. A. C.; Visschedijk, A. J. H.; Charalampidis, P.; Pilinis, C.; Pandis, S. N.

    2014-04-01

    We use a 3-D regional chemical transport model, with the latest advancements in the organic aerosol (OA) treatment, and an updated emission inventory for wood combustion to study the organic aerosol change in response to the replacement of current residential wood combustion technologies with pellet stoves. Simulations show a large decrease of fine organic aerosol (more than 60%) in urban and suburban areas during winter and decreases of 30-50% in elemental carbon levels in large parts of Europe. There is also a considerable decrease (around 40%) of oxidized OA, mostly in rural and remote regions. Total PM2.5 mass is predicted to decrease by 15-40% on average during the winter in continental Europe. Accurate representation of the intermediate volatility precursors of organic aerosol in the emission inventory is crucial in assessing the efficiency of such abatement strategies.

  6. Secondary Aerosol: Precursors and Formation Mechanisms. Technical Report on Grant

    SciTech Connect

    Weinstein-Lloyd, Judith B

    2009-05-04

    This project focused on studying trace gases that participate in chemical reactions that form atmospheric aerosols. Ammonium sulfate is a major constituent of these tiny particles, and one important pathway to sulfate formation is oxidation of dissolved sulfur dioxide by hydrogen peroxide in cloud, fog and rainwater. Sulfate aerosols influence the number and size of cloud droplets, and since these factors determine cloud radiative properties, sulfate aerosols also influence climate. Peroxide measurements, in conjunction with those of other gaseous species, can used to distinguish the contribution of in-cloud reaction to new sulfate aerosol formation from gas-phase nucleation reactions. This will lead to more reliable global climate models. We constructed and tested a new 4-channel fluorescence detector for airborne detection of peroxides. We integrated the instrument on the G-1 in January, 2006 and took a test flight in anticipation of the MAX-Mex field program, where we planned to fly under pressurized conditions for the first time. We participated in the 2006 Megacity Initiative: Local and Global Research Observations (MILAGRO) - Megacity Aerosol EXperiment Mexico City (MAX-Mex) field measurement campaign. Peroxide instrumentation was deployed on the DOE G-1 research aircraft based in Veracruz, and at the surface site at Tecamac University.

  7. Have tropospheric aerosol emissions contributed to the recent climate hiatus?

    NASA Astrophysics Data System (ADS)

    Kühn, Thomas; Partanen, Antti-Ilari; Laakso, Anton; Lu, Zifeng; Bergman, Tommi; Mikkonen, Santtu; Kokkola, Harri; Korhonen, Hannele; Räisänen, Petri; Streets, David G.; Romakkaniemi, Sami; Laaksonen, Ari

    2014-05-01

    During the last 15 years global warming has slowed considerably, with the resulting plateau in global temperature records being dubbed the climate hiatus. Apart from variations in solar irradiance and ocean temperature, increased anthropogenic aerosol emissions in South and East Asia have been suggested as possible causes for this hiatus. While European and and North American aerosol emissions have constantly decreased since the 1980's, emissions in China and India have started increasing at the same time and, although total global aerosol emissions have decreased, aerosol effects on the global energy budget are expected to enhance towards the equator due to stronger irradiance there. In this study we used the aerosol-climate model ECHAM5-HAM2 to assess the effect that this re-distribution of anthropogenic aerosol emissions towards the equator may have on climate. To this end, we computed radiative forcing and equilibrium temperature response due to the change in global aerosol emissions (black carbon (BC), organic carbon and sulphur dioxide) between 1996 and 2010, keeping all other anthropogenic influences fixed. Surprisingly we found that the cooling due the increased aerosol emissions in China and India is almost negligible compared to the warming caused by the decreasing aerosol emissions in Europe and North America. The radiative flux perturbation (RFP; includes aerosol indirect effects) was 0.42 W/m2 and the change in global equilibrium 2 m temperature increased by 0.25 °C. The lack of cooling in China and India stems from a cancellation of sulfate cooling and BC warming, especially over China. There, the strong cloud cover leads to both attenuation of sulphate aerosol light scattering and saturation tendency of indirect aerosol effects on clouds. BC levels on the other hand increase also above the clouds (relative increase of BC levels is almost uniform with height), leading to warming through light absorption.

  8. Secondary organic aerosol formation from gasoline passenger vehicle emissions investigated in a smog chamber

    NASA Astrophysics Data System (ADS)

    Nordin, E. Z.; Eriksson, A. C.; Roldin, P.; Nilsson, P. T.; Carlsson, J. E.; Kajos, M. K.; Hellén, H.; Wittbom, C.; Rissler, J.; Löndahl, J.; Swietlicki, E.; Svenningsson, B.; Bohgard, M.; Kulmala, M.; Hallquist, M.; Pagels, J.

    2012-12-01

    Gasoline vehicles have elevated emissions of volatile organic compounds during cold starts and idling and have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from one Euro II, one Euro III and one Euro IV passenger vehicles were investigated using photo-oxidation experiments in a 6 m3 smog chamber. The experiments were carried out at atmospherically relevant organic aerosol mass concentrations. The characterization methods included a high resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind urban areas. After 4 h aging the formed SOA was 1-2 orders of magnitude higher than the Primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f43 (mass fraction at m/z = 4 3) approximately two times higher than to the gasoline SOA. However O : C and H : C ratios were similar for the two cases. Classical C6-C9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher order aromatic compounds such as C10, C11 light aromatics, naphthalene and methyl-naphthalenes.

  9. Secondary organic aerosol formation from idling gasoline passenger vehicle emissions investigated in a smog chamber

    NASA Astrophysics Data System (ADS)

    Nordin, E. Z.; Eriksson, A. C.; Roldin, P.; Nilsson, P. T.; Carlsson, J. E.; Kajos, M. K.; Hellén, H.; Wittbom, C.; Rissler, J.; Löndahl, J.; Swietlicki, E.; Svenningsson, B.; Bohgard, M.; Kulmala, M.; Hallquist, M.; Pagels, J. H.

    2013-06-01

    Gasoline vehicles have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from three passenger vehicles (EURO2-EURO4) were investigated with photo-oxidation experiments in a 6 m3 smog chamber. The experiments were carried out down to atmospherically relevant organic aerosol mass concentrations. The characterization instruments included a high-resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind of urban areas. After a cumulative OH exposure of ~5 × 106 cm-3 h, the formed SOA was 1-2 orders of magnitude higher than the primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f43 (mass fraction at m/z = 43), approximately two times higher than to the gasoline SOA. However O : C and H : C ratios were similar for the two cases. Classical C6-C9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher-order aromatic compounds such as C10 and C11 light aromatics, naphthalene and methyl-naphthalenes. We conclude that approaches using only light aromatic precursors give an incomplete picture of the magnitude of SOA formation and the SOA composition from gasoline exhaust.

  10. Semi-quantitative characterisation of ambient ultrafine aerosols resulting from emissions of coal fired power stations.

    PubMed

    Hinkley, J T; Bridgman, H A; Buhre, B J P; Gupta, R P; Nelson, P F; Wall, T F

    2008-02-25

    Emissions from coal fired power stations are known to be a significant anthropogenic source of fine atmospheric particles, both through direct primary emissions and secondary formation of sulfate and nitrate from emissions of gaseous precursors. However, there is relatively little information available in the literature regarding the contribution emissions make to the ambient aerosol, particularly in the ultrafine size range. In this study, the contribution of emissions to particles smaller than 0.3 mum in the ambient aerosol was examined at a sampling site 7 km from two large Australian coal fired power stations equipped with fabric filters. A novel approach was employed using conditional sampling based on sulfur dioxide (SO(2)) as an indicator species, and a relatively new sampler, the TSI Nanometer Aerosol Sampler. Samples were collected on transmission electron microscope (TEM) grids and examined using a combination of TEM imaging and energy dispersive X-ray (EDX) analysis for qualitative chemical analysis. The ultrafine aerosol in low SO(2) conditions was dominated by diesel soot from vehicle emissions, while significant quantities of particles, which were unstable under the electron beam, were observed in the high SO(2) samples. The behaviour of these particles was consistent with literature accounts of sulfate and nitrate species, believed to have been derived from precursor emissions from the power stations. A significant carbon peak was noted in the residues from the evaporated particles, suggesting that some secondary organic aerosol formation may also have been catalysed by these acid seed particles. No primary particulate material was observed in the minus 0.3 mum fraction. The results of this study indicate the contribution of species more commonly associated with gas to particle conversion may be more significant than expected, even close to source.

  11. Influence of Aerosol Acidity on the Formation of Secondary Organic Aerosol from Biogenic Precursor Hydrocarbons

    EPA Science Inventory

    Secondary organic aerosol (SOA) formation and dynamics may be important factors for the role of aerosols in adverse health effects, visibility and climate change. Formation of SOA occurs when a parent volatile organic compound is oxidized to create products that form in a conden...

  12. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

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

    PubMed

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

    2016-06-28

    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.

  15. Secondary organic aerosol formation from gasoline vehicle emissions in a new mobile environmental reaction chamber

    NASA Astrophysics Data System (ADS)

    Platt, S. M.; El Haddad, I.; Zardini, A. A.; Clairotte, M.; Astorga, C.; Wolf, R.; Slowik, J. G.; Temime-Roussel, B.; Marchand, N.; Ježek, I.; Drinovec, L.; Močnik, G.; Möhler, O.; Richter, R.; Barmet, P.; Bianchi, F.; Baltensperger, U.; Prévôt, A. S. H.

    2013-09-01

    We present a new mobile environmental reaction chamber for the simulation of the atmospheric aging of different emission sources without limitation from the instruments or facilities available at any single site. Photochemistry is simulated using a set of 40 UV lights (total power 4 KW). Characterisation of the emission spectrum of these lights shows that atmospheric aging of emissions may be simulated over a range of temperatures (-7 to 25 °C). A photolysis rate of NO2, JNO2, of (8.0 ± 0.7) × 10-3 s-1 was determined at 25 °C. We demonstrate the utility of this new system by presenting results on the aging (OH = 12 × 106 cm-3 h) of emissions from a modern (Euro 5) gasoline car operated during a driving cycle (New European Driving Cycle, NEDC) on a chassis dynamometer in a vehicle test cell. Emissions from the entire NEDC were sampled and aged in the chamber. Total organic aerosol (OA; primary organic aerosol (POA) emission + secondary organic aerosol (SOA) formation) was (369.8-397.5)10-3 g kg-1 fuel, or (13.2-15.4) × 10-3 g km-1, after aging, with aged OA/POA in the range 9-15. A thorough investigation of the composition of the gas phase emissions suggests that the observed SOA is from previously unconsidered precursors and processes. This large enhancement in particulate matter mass from gasoline vehicle aerosol emissions due to SOA formation, if it occurs across a wider range of gasoline vehicles, would have significant implications for our understanding of the contribution of on-road gasoline vehicles to ambient aerosols.

  16. Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions.

    PubMed

    Gentner, Drew R; Jathar, Shantanu H; Gordon, Timothy D; Bahreini, Roya; Day, Douglas A; El Haddad, Imad; Hayes, Patrick L; Pieber, Simone M; Platt, Stephen M; de Gouw, Joost; Goldstein, Allen H; Harley, Robert A; Jimenez, Jose L; Prévôt, André S H; Robinson, Allen L

    2017-02-07

    Secondary organic aerosol (SOA) is formed from the atmospheric oxidation of gas-phase organic compounds leading to the formation of particle mass. Gasoline- and diesel-powered motor vehicles, both on/off-road, are important sources of SOA precursors. They emit complex mixtures of gas-phase organic compounds that vary in volatility and molecular structure-factors that influence their contributions to urban SOA. However, the relative importance of each vehicle type with respect to SOA formation remains unclear due to conflicting evidence from recent laboratory, field, and modeling studies. Both are likely important, with evolving contributions that vary with location and over short time scales. This review summarizes evidence, research needs, and discrepancies between top-down and bottom-up approaches used to estimate SOA from motor vehicles, focusing on inconsistencies between molecular-level understanding and regional observations. The effect of emission controls (e.g., exhaust aftertreatment technologies, fuel formulation) on SOA precursor emissions needs comprehensive evaluation, especially with international perspective given heterogeneity in regulations and technology penetration. Novel studies are needed to identify and quantify "missing" emissions that appear to contribute substantially to SOA production, especially in gasoline vehicles with the most advanced aftertreatment. Initial evidence suggests catalyzed diesel particulate filters greatly reduce emissions of SOA precursors along with primary aerosol.

  17. The impact of residential combustion emissions on atmospheric aerosol, human health, and climate

    NASA Astrophysics Data System (ADS)

    Butt, E. W.; Rap, A.; Schmidt, A.; Scott, C. E.; Pringle, K. J.; Reddington, C. L.; Richards, N. A. D.; Woodhouse, M. T.; Ramirez-Villegas, J.; Yang, H.; Vakkari, V.; Stone, E. A.; Rupakheti, M.; Praveen, P. S.; van Zyl, P. G.; Beukes, J. P.; Josipovic, M.; Mitchell, E. J. S.; Sallu, S. M.; Forster, P. M.; Spracklen, D. V.

    2016-01-01

    Combustion of fuels in the residential sector for cooking and heating results in the emission of aerosol and aerosol precursors impacting air quality, human health, and climate. Residential emissions are dominated by the combustion of solid fuels. We use a global aerosol microphysics model to simulate the impact of residential fuel combustion on atmospheric aerosol for the year 2000. The model underestimates black carbon (BC) and organic carbon (OC) mass concentrations observed over Asia, Eastern Europe, and Africa, with better prediction when carbonaceous emissions from the residential sector are doubled. Observed seasonal variability of BC and OC concentrations are better simulated when residential emissions include a seasonal cycle. The largest contributions of residential emissions to annual surface mean particulate matter (PM2.5) concentrations are simulated for East Asia, South Asia, and Eastern Europe. We use a concentration response function to estimate the human health impact due to long-term exposure to ambient PM2.5 from residential emissions. We estimate global annual excess adult (> 30 years of age) premature mortality (due to both cardiopulmonary disease and lung cancer) to be 308 000 (113 300-497 000, 5th to 95th percentile uncertainty range) for monthly varying residential emissions and 517 000 (192 000-827 000) when residential carbonaceous emissions are doubled. Mortality due to residential emissions is greatest in Asia, with China and India accounting for 50 % of simulated global excess mortality. Using an offline radiative transfer model we estimate that residential emissions exert a global annual mean direct radiative effect between -66 and +21 mW m-2, with sensitivity to the residential emission flux and the assumed ratio of BC, OC, and SO2 emissions. Residential emissions exert a global annual mean first aerosol indirect effect of between -52 and -16 mW m-2, which is sensitive to the assumed size distribution of carbonaceous emissions

  18. “APEC Blue”: Secondary Aerosol Reductions from Emission Controls in Beijing

    NASA Astrophysics Data System (ADS)

    Sun, Yele; Wang, Zifa; Wild, Oliver; Xu, Weiqi; Chen, Chen; Fu, Pingqing; Du, Wei; Zhou, Libo; Zhang, Qi; Han, Tingting; Wang, Qingqing; Pan, Xiaole; Zheng, Haitao; Li, Jie; Guo, Xiaofeng; Liu, Jianguo; Worsnop, Douglas R.

    2016-02-01

    China implemented strict emission control measures in Beijing and surrounding regions to ensure good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit. We conducted synchronous aerosol particle measurements with two aerosol mass spectrometers at different heights on a meteorological tower in urban Beijing to investigate the variations in particulate composition, sources and size distributions in response to emission controls. Our results show consistently large reductions in secondary inorganic aerosol (SIA) of 61–67% and 51–57%, and in secondary organic aerosol (SOA) of 55% and 37%, at 260 m and ground level, respectively, during the APEC summit. These changes were mainly caused by large reductions in accumulation mode particles and by suppression of the growth of SIA and SOA by a factor of 2–3, which led to blue sky days during APEC commonly referred to as “APEC Blue”. We propose a conceptual framework for the evolution of primary and secondary species and highlight the importance of regional atmospheric transport in the formation of severe pollution episodes in Beijing. Our results indicate that reducing the precursors of secondary aerosol over regional scales is crucial and effective in suppressing the formation of secondary particulates and mitigating PM pollution.

  19. “APEC Blue”: Secondary Aerosol Reductions from Emission Controls in Beijing

    PubMed Central

    Sun, Yele; Wang, Zifa; Wild, Oliver; Xu, Weiqi; Chen, Chen; Fu, Pingqing; Du, Wei; Zhou, Libo; Zhang, Qi; Han, Tingting; Wang, Qingqing; Pan, Xiaole; Zheng, Haitao; Li, Jie; Guo, Xiaofeng; Liu, Jianguo; Worsnop, Douglas R.

    2016-01-01

    China implemented strict emission control measures in Beijing and surrounding regions to ensure good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit. We conducted synchronous aerosol particle measurements with two aerosol mass spectrometers at different heights on a meteorological tower in urban Beijing to investigate the variations in particulate composition, sources and size distributions in response to emission controls. Our results show consistently large reductions in secondary inorganic aerosol (SIA) of 61–67% and 51–57%, and in secondary organic aerosol (SOA) of 55% and 37%, at 260 m and ground level, respectively, during the APEC summit. These changes were mainly caused by large reductions in accumulation mode particles and by suppression of the growth of SIA and SOA by a factor of 2–3, which led to blue sky days during APEC commonly referred to as “APEC Blue”. We propose a conceptual framework for the evolution of primary and secondary species and highlight the importance of regional atmospheric transport in the formation of severe pollution episodes in Beijing. Our results indicate that reducing the precursors of secondary aerosol over regional scales is crucial and effective in suppressing the formation of secondary particulates and mitigating PM pollution. PMID:26891104

  20. Primary particulate emissions and secondary organic aerosol (SOA) formation from idling diesel vehicle exhaust in China.

    PubMed

    Deng, Wei; Hu, Qihou; Liu, Tengyu; Wang, Xinming; Zhang, Yanli; Song, Wei; Sun, Yele; Bi, Xinhui; Yu, Jianzhen; Yang, Weiqiang; Huang, Xinyu; Zhang, Zhou; Huang, Zhonghui; He, Quanfu; Mellouki, Abdelwahid; George, Christian

    2017-03-26

    In China diesel vehicles dominate the primary emission of particulate matters from on-road vehicles, and they might also contribute substantially to the formation of secondary organic aerosols (SOA). In this study tailpipe exhaust of three typical in-use diesel vehicles under warm idling conditions was introduced directly into an indoor smog chamber with a 30m(3) Teflon reactor to characterize primary emissions and SOA formation during photo-oxidation. The emission factors of primary organic aerosol (POA) and black carbon (BC) for the three types of Chinese diesel vehicles ranged 0.18-0.91 and 0.15-0.51gkg-fuel(-1), respectively; and the SOA production factors ranged 0.50-1.8gkg-fuel(-1) and SOA/POA ratios ranged 0.7-3.7 with an average of 2.2. The fuel-based POA emission factors and SOA production factors from this study for idling diesel vehicle exhaust were 1-3 orders of magnitude higher than those reported in previous studies for idling gasoline vehicle exhaust. The emission factors for total particle numbers were 0.65-4.0×10(15)particleskg-fuel(-1), and particles with diameters less than 50nm dominated in total particle numbers. Traditional C2-C12 precursor non-methane hydrocarbons (NMHCs) could only explain less than 3% of the SOA formed during aging and contribution from other precursors including intermediate volatile organic compounds (IVOC) needs further investigation.

  1. Identifying precursors and aqueous organic aerosol formation pathways during the SOAS campaign

    NASA Astrophysics Data System (ADS)

    Sareen, Neha; Carlton, Annmarie G.; Surratt, Jason D.; Gold, Avram; Lee, Ben; Lopez-Hilfiker, Felipe D.; Mohr, Claudia; Thornton, Joel A.; Zhang, Zhenfa; Lim, Yong B.; Turpin, Barbara J.

    2016-11-01

    Aqueous multiphase chemistry in the atmosphere can lead to rapid transformation of organic compounds, forming highly oxidized, low-volatility organic aerosol and, in some cases, light-absorbing (brown) carbon. Because liquid water is globally abundant, this chemistry could substantially impact climate, air quality, and health. Gas-phase precursors released from biogenic and anthropogenic sources are oxidized and fragmented, forming water-soluble gases that can undergo reactions in the aqueous phase (in clouds, fogs, and wet aerosols), leading to the formation of secondary organic aerosol (SOAAQ). Recent studies have highlighted the role of certain precursors like glyoxal, methylglyoxal, glycolaldehyde, acetic acid, acetone, and epoxides in the formation of SOAAQ. The goal of this work is to identify additional precursors and products that may be atmospherically important. In this study, ambient mixtures of water-soluble gases were scrubbed from the atmosphere into water at Brent, Alabama, during the 2013 Southern Oxidant and Aerosol Study (SOAS). Hydroxyl (OH⚫) radical oxidation experiments were conducted with the aqueous mixtures collected from SOAS to better understand the formation of SOA through gas-phase followed by aqueous-phase chemistry. Total aqueous-phase organic carbon concentrations for these mixtures ranged from 92 to 179 µM-C, relevant for cloud and fog waters. Aqueous OH-reactive compounds were primarily observed as odd ions in the positive ion mode by electrospray ionization mass spectrometry (ESI-MS). Ultra high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) spectra and tandem MS (MS-MS) fragmentation of these ions were consistent with the presence of carbonyls and tetrols. Products were observed in the negative ion mode and included pyruvate and oxalate, which were confirmed by ion chromatography. Pyruvate and oxalate have been found in the particle phase in many locations (as salts and complexes). Thus

  2. Infrared Emission from Gas-Aerosol Reactions

    DTIC Science & Technology

    1982-09-01

    Gaseous Amonia Infrared (IR) "Gas-aerosol Reactions Sulfuric Acid- amonia IR Luminescence Exothermic Reactions Octanoic Acid- amonia IR Laser Acid-base...of radiation observed from the reactions of chloro- sulfuric acid aerosol with gaseous amonia and water. Other systems which were screened including...phase diffusion, diffusion of reactants and/or products in the particle, by the bulk chemical reaction, or by processes occurring in the droplet

  3. Unique airborne measurements at the tropopause of Fukushima Xe-133, aerosol, and aerosol precursors indicate aerosol formation via homogeneous and cosmic ray induced nucleation

    NASA Astrophysics Data System (ADS)

    Schlager, Hans; Arnold, Frank; Aufmhoff, Heinfried; Minikin, Andreas; Baumann, Robert; Simgen, Hardy; Lindemann, Stefan; Rauch, Ludwig; Kaether, Frank; Pirjola, Liisa; Schumann, Ulrich

    2014-05-01

    We report unique airborne measurements, at the tropopause, of the Fukushima radio nuclide Xe-133, aerosol particles (size, shape, number concentration, volatility), aerosol precursor gases (particularly SO2, HNO3, H2O). Our measurements and accompanying model simulations indicate homogeneous and cosmic ray induced aerosol formation at the tropopause. Using an extremely sensitive detection method, we managed to detect Fukushima Xe-133, an ideal transport tracer, at and even above the tropopause. To our knowledge, these airborne Xe-133 measurements are the only of their kind. Our investigations represent a striking example how a pioneering measurement of a Fukshima radio nuclide, employing an extremely sensitive method, can lead to new insights into an important atmospheric process. After the Fukushima accidential Xe-133 release (mostly during 11-15 March 2011), we have conducted two aircraft missions, which took place over Central Europe, on 23 March and 11 April 2011. In the air masses, encountered by the research aircraft on 23 March, we have detected Fukushima Xe-133 by an extremely sensitive method, at and even above the tropopause. Besides increased concentrations of Xe-133, we have detected also increased concentrations of the gases SO2, HNO3, and H2O. The Xe-133 data and accompanying transport model simulations indicate that a West-Pacific Warm Conveyor Belt (WCB) lifted East-Asian planetary boundary layer air to and even above the tropopause, followed by relatively fast quasi-horizontal advection to Europe. Along with Xe-133, anthropogenic SO2, NOx (mostly released from East-Asian ground-level combustion sources), and warer vapour were also lifted by the WCB. After the lift, SO2 and NOx experienced efficient solar UV-radiation driven conversion to the important aerosol precursors gases H2SO4 and HNO3. Our investigations indicate that, increased concentrations of the gases SO2, HNO3, and H2O promoted homogeneous and cosmic ray induced aerosol formation at and

  4. Global volcanic aerosol properties derived from emissions, 1990-2014, using CESM1(WACCM): VOLCANIC AEROSOLS DERIVED FROM EMISSIONS

    SciTech Connect

    Mills, Michael J.; Schmidt, Anja; Easter, Richard; Solomon, Susan; Kinnison, Douglas E.; Ghan, Steven J.; Neely, Ryan R.; Marsh, Daniel R.; Conley, Andrew; Bardeen, Charles G.; Gettelman, Andrew

    2016-03-06

    Accurate representation of global stratospheric aerosol properties from volcanic and non-volcanic sulfur emissions is key to understanding the cooling effects and ozone-loss enhancements of recent volcanic activity. Attribution of climate and ozone variability to volcanic activity is of particular interest in relation to the post-2000 slowing in the apparent rate of global average temperature increases, and variable recovery of the Antarctic ozone hole. We have developed a climatology of global aerosol properties from 1990 to 2014 calculated based on volcanic and non-volcanic emissions of sulfur sources. We have complied a database of volcanic SO2 emissions and plume altitudes for eruptions between 1990 and 2014, and a new prognostic capability for simulating stratospheric sulfate aerosols in version 5 of the Whole Atmosphere Community Climate Model, a component of the Community Earth System Model. Our climatology shows remarkable agreement with ground-based lidar observations of stratospheric aerosol optical depth (SAOD), and with in situ measurements of aerosol surface area density (SAD). These properties are key parameters in calculating the radiative and chemical effects of stratospheric aerosols. Our SAOD climatology represents a significant improvement over satellite-based analyses, which ignore aerosol extinction below 15 km, a region that can contain the vast majority of stratospheric aerosol extinction at mid- and high-latitudes. Our SAD climatology significantly improves on that provided for the Chemistry-Climate Model Initiative, which misses 60% of the SAD measured in situ. Our climatology of aerosol properties is publicly available on the Earth System Grid.

  5. Uncertainties in Carbonaceous Aerosol Emissions, Scavenging Parameterizations, and Optical Properties

    NASA Astrophysics Data System (ADS)

    Koch, D.; Bond, T.; Kinne, S.; Klimont, Z.; Sun, H.; van Aardenne, J.; van der Werf, G.

    2006-12-01

    Estimates of human influence on climate are especially hindered by poor constraint on the amount of anthropogenic carbonaceous aerosol absorption in the atmosphere. Coordination of observation and model analyses attempt to constrain particle absorption amount, however these are limited by uncertainties in aerosol emission estimates, model scavenging parameterization, aerosol size assumption, contributions from organic aerosol absorption, air concentration observational techniques and by sparsity of data coverage. We perform multiple simulations using GISS modelE and six present-day emission estimates for black carbon (BC) and organic carbon (OC) (Bond et al 2004 middle and upper estimates, IIASA, EDGAR, GFED v1 and v2); for one of these emissions we apply 4 different BC/OC scavenging parameterizations. The resulting concentrations will be compared with a new compilation of observed BC/OC concentrations. We then use these model concentrations, together with effective radius assumptions and estimates of OC absorption to calculate a range of carbonaceous aerosol absorption. We constrain the wavelength-dependent model τ- absorption with AERONET sun-photometer observations. We will discuss regions, seasons and emission sectors with greatest uncertainty, including those where observational constraint is lacking. We calculate the range of model radiative forcing from our simulations and discuss the degree to which it is constrained by observations.

  6. Top-Down Inversion of Aerosol Emissions through Adjoint Integration of Satellite Radiance and GEOS-Chem Chemical Transport Model

    NASA Astrophysics Data System (ADS)

    Xu, X.; Wang, J.; Henze, D. K.; Qu, W.; Kopacz, M.

    2012-12-01

    The knowledge of aerosol emissions from both natural and anthropogenic sources are needed to study the impacts of tropospheric aerosol on atmospheric composition, climate, and human health, but large uncertainties persist in quantifying the aerosol sources with the current bottom-up methods. This study presents a new top-down approach that spatially constrains the amount of aerosol emissions from satellite (MODIS) observed reflectance with the adjoint of a chemistry transport model (GEOS-Chem). We apply this technique with a one-month case study (April 2008) over the East Asia. The bottom-up estimated sulfate-nitrate-ammonium precursors, such as sulfur dioxide (SO2), ammonia (NH3), and nitrogen oxides (NOx), all from INTEX-B 2006 inventory, emissions of black carbon (BC), organic carbon (OC) from Bond-2007 inventory, and mineral dust simulated from DEAD dust mobilization scheme, are spatially optimized from the GEOS-Chem model and its adjoint constrained by the aerosol optical depth (AOD) that are derived from MODIS reflectance with the GEOS-Chem aerosol single scattering properties. The adjoint inverse modeling for the study period yields notable decreases in anthropogenic aerosol emissions over China: 436 Gg (33.5%) for SO2, 378 Gg (34.5%) for NH3, 319 (18.8%) for NOx, 10 Gg (9.1%) for BC, and 30 Gg (15.0%) for OC. The total amount of the mineral dust emission is reduced by 56.4% from the DEAD mobilization module which simulates dust production of 19020 Gg. Sub-regional adjustments are significant and directions of changes are spatially different. The model simulation with optimized aerosol emissions shows much better agreement with independent observations from sun-spectrophotometer observed AOD from AERONET, MISR (Multi-angle Imaging SpectroRadiometer) AOD, OMI (Ozone Monitoring Instrument) NO2 and SO2 columns, and surface aerosol concentrations measured over both anthropogenic pollution and dust source regions. Assuming the used bottom-up anthropogenic

  7. A simple parameterization of aerosol emissions in RAMS

    NASA Astrophysics Data System (ADS)

    Letcher, Theodore

    Throughout the past decade, a high degree of attention has been focused on determining the microphysical impact of anthropogenically enhanced concentrations of Cloud Condensation Nuclei (CCN) on orographic snowfall in the mountains of the western United States. This area has garnered a lot of attention due to the implications this effect may have on local water resource distribution within the Region. Recent advances in computing power and the development of highly advanced microphysical schemes within numerical models have provided an estimation of the sensitivity that orographic snowfall has to changes in atmospheric CCN concentrations. However, what is still lacking is a coupling between these advanced microphysical schemes and a real-world representation of CCN sources. Previously, an attempt to representation the heterogeneous evolution of aerosol was made by coupling three-dimensional aerosol output from the WRF Chemistry model to the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS) (Ward et al. 2011). The biggest problem associated with this scheme was the computational expense. In fact, the computational expense associated with this scheme was so high, that it was prohibitive for simulations with fine enough resolution to accurately represent microphysical processes. To improve upon this method, a new parameterization for aerosol emission was developed in such a way that it was fully contained within RAMS. Several assumptions went into generating a computationally efficient aerosol emissions parameterization in RAMS. The most notable assumption was the decision to neglect the chemical processes in formed in the formation of Secondary Aerosol (SA), and instead treat SA as primary aerosol via short-term WRF-CHEM simulations. While, SA makes up a substantial portion of the total aerosol burden (much of which is made up of organic material), the representation of this process is highly complex and highly expensive within a numerical

  8. Marine Aerosol Precursor Emissions for Earth System Models

    SciTech Connect

    Maltrud, Mathew Einar

    2016-07-25

    Dimethyl sulfide (DMS) is generated by marine ecosystems and plays a major role in cloud formation over the ocean. Currently, Earth System Models use imposed flux of DMS from the ocean to the atmosphere that is independent of the climate state. We have added DMS as a prognostic variable to the Community Earth System Model (CESM) that depends on the distribution of phytoplankton species, and thus changes with climate.

  9. Measurement of gas and aerosol agricultural emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies of air quality indicate that agricultural emissions may impact particulate mass concentrations through both primary and secondary processes. Agriculture impacts can include primary dust emission, on-facility combustion from vehicles or seasonal field burning, and gaseous emissions from waste...

  10. Secondary organic aerosol formation from road vehicle emissions

    NASA Astrophysics Data System (ADS)

    Pieber, Simone M.; Platt, Stephen M.; El Haddad, Imad; Zardini, Alessandro A.; Suarez-Bertoa, Ricardo; Slowik, Jay G.; Huang, Ru-Jin; Hellebust, Stig; Temime-Roussel, Brice; Marchand, Nicolas; Drinovec, Luca; Mocnik, Grisa; Baltensperger, Urs; Astorga, Covadogna; Prévôt, André S. H.

    2014-05-01

    Organic aerosol particles (OA) are a major fraction of the submicron particulate matter. OA consists of directly emitted primary (POA) and secondary OA (SOA). SOA is formed in-situ in the atmosphere via the reaction of volatile organic precursors. The partitioning of SOA species depends not only on the exposure to oxidants, but for instance also on temperature, relative humidity (RH), and the absorptive mass chemical composition (presence of inorganics) and concentration. Vehicle exhaust is a known source of POA and likely contributes to SOA formation in urban areas [1;2]. This has recently been estimated by (i) analyzing ambient data from urban areas combined with fuel consumption data [3], (ii) by examining the chemical composition of raw fuels [4], or (iii) smog chamber studies [5, 6]. Contradictory and thus somewhat controversial results in the relative quantity of SOA from diesel vs. gasoline vehicle exhaust were observed. In order to elucidate the impact of variable ambient conditions on the potential SOA formation of vehicle exhaust, and its relation to the emitted gas phase species, we studied SOA formed from the exhaust of passenger cars and trucks as a function of fuel and engine type (gasoline, diesel) at different temperatures (T 22 vs. -7oC) and RH (40 vs. 90%), as well as with different levels of inorganic salt concentrations. The exhaust was sampled at the tailpipe during regulatory driving cycles on chassis dynamometers, diluted (200 - 400x) and introduced into the PSI mobile smog chamber [6], where the emissions were subjected to simulated atmospheric ageing. Particle phase instruments (HR-ToF-AMS, aethalometers, CPC, SMPS) and gas phase instruments (PTR-TOF-MS, CO, CO2, CH4, THC, NH3 and other gases) were used online during the experiments. We found that gasoline emissions, because of cold starts, were generally larger than diesel, especially during cold temperatures driving cycles. Gasoline vehicles also showed the highest SOA formation

  11. Model evaluation of marine primary organic aerosol emission schemes

    NASA Astrophysics Data System (ADS)

    Gantt, B.; Johnson, M. S.; Meskhidze, N.; Sciare, J.; Ovadnevaite, J.; Ceburnis, D.; O'Dowd, C. D.

    2012-09-01

    In this study, several marine primary organic aerosol (POA) emission schemes have been evaluated using the GEOS-Chem chemical transport model in order to provide guidance for their implementation in air quality and climate models. These emission schemes, based on varying dependencies of chlorophyll a concentration ([chl a]) and 10 m wind speed (U10), have large differences in their magnitude, spatial distribution, and seasonality. Model comparison with weekly and monthly mean values of the organic aerosol mass concentration at two coastal sites shows that the source function exclusively related to [chl a] does a better job replicating surface observations. Sensitivity simulations in which the negative U10 and positive [chl a] dependence of the organic mass fraction of sea spray aerosol are enhanced show improved prediction of the seasonality of the marine POA concentrations. A top-down estimate of submicron marine POA emissions based on the parameterization that compares best to the observed weekly and monthly mean values of marine organic aerosol surface concentrations has a global average emission rate of 6.3 Tg yr-1. Evaluation of existing marine POA source functions against a case study during which marine POA contributed the major fraction of submicron aerosol mass shows that none of the existing parameterizations are able to reproduce the hourly-averaged observations. Our calculations suggest that in order to capture episodic events and short-term variability in submicron marine POA concentration over the ocean, new source functions need to be developed that are grounded in the physical processes unique to the organic fraction of sea spray aerosol.

  12. Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations

    NASA Astrophysics Data System (ADS)

    Zhao, Y.

    2015-12-01

    To better understand the levels and trends of carbonaceous aerosol emissions and the resulting ambient concentrations in China, we update an emission inventory of anthropogenic organic carbon (OC) and elemental carbon (EC) and employ existing observational studies to analyze characteristics of these aerosols including temporal and spatial distributions, and the levels and shares of secondary organic carbon (SOC) in total OC. We further use ground observations to test the levels and inter-annual trends of the calculated national and provincial emissions of carbonaceous aerosols. The national OC emissions are estimated to have increased 29% from 2000 (2127 Gg) to 2012 (2749 Gg) and EC by 37% (from 1356 to 1857 Gg). Updated emission factors based on the most recent local field measurements, particularly for biofuel stoves, lead to considerably lower emissions of OC compared to previous inventories. Compiling observational data across the country, higher concentrations of OC and EC are found in northern and inland cities, while SOC/OC ratios are found in southern cities, due to the joint effects of primary emissions and meteorology. Higher OC/EC ratios are estimated at rural and remote sites compared to urban ones, attributed to more emissions of OC from biofuel use, more biogenic emissions of volatile organic compound (VOC) precursors to SOC, and/or transport of aged aerosols. For most sites, smaller SOC/OC is found for cold seasons, particularly at rural and remote sites, attributed partly to weaker atmospheric oxidation and SOC formation in winter. Enhanced SOC formation from oxidization and anthropogenic activities like biomass combustion is judged to have crucial effects on severe haze events characterized by high particle concentrations. Several observational studies indicate an increasing trend in ambient OC/EC (but not in OC or EC individually) from 2000 to 2010, confirming increased atmospheric oxidation of OC across the country. Combining the results of

  13. Airborne studies of aerosol emissions from savanna fires in southern Africa: 2. Aerosol chemical composition

    NASA Astrophysics Data System (ADS)

    Andreae, M. O.; Andreae, T. W.; Annegarn, H.; Beer, J.; Cachier, H.; Le Canut, P.; Elbert, W.; Maenhaut, W.; Salma, I.; Wienhold, F. G.; Zenker, T.

    1998-12-01

    We investigated smoke emissions from fires in savanna, forest, and agricultural ecosystems by airborne sampling of plumes close to prescribed burns and incidental fires in southern Africa. Aerosol samples were collected on glass fiber filters and on stacked filter units, consisting of a Nuclepore prefilter for particles larger than ˜1-2 μm and a Teflon second filter stage for the submicron fraction. The samples were analyzed for soluble ionic components, organic carbon, and black carbon. Onboard the research aircraft, particle number and volume distributions as a function of size were determined with a laser-optical particle counter and the black carbon content of the aerosol with an aethalometer. We determined the emission ratios (relative to CO2 and CO) and emission factors (relative to the amount of biomass burnt) for the various aerosol constituents. The smoke aerosols were rich in organic and black carbon, the latter representing 10-30% of the aerosol mass. K+ and NH4+ were the dominant cationic species in the smoke of most fires, while Cl- and SO42- were the most important anions. The aerosols were unusually rich in Cl-, probably due to the high Cl content of the semiarid vegetation. Comparison of the element budget of the fuel before and after the fires shows that the fraction of the elements released during combustion is highly variable between elements. In the case of the halogen elements, almost the entire amount released during the fire is present in the aerosol phase, while in the case of C, N, and S, only a small proportion ends up as particulate matter. This suggests that the latter elements are present predominantly as gaseous species in the fresh fire plumes studied here.

  14. Land cover maps, BVOC emissions, and SOA burden in a global aerosol-climate model

    NASA Astrophysics Data System (ADS)

    Stanelle, Tanja; Henrot, Alexandra; Bey, Isaelle

    2015-04-01

    It has been reported that different land cover representations influence the emission of biogenic volatile organic compounds (BVOC) (e.g. Guenther et al., 2006). But the land cover forcing used in model simulations is quite uncertain (e.g. Jung et al., 2006). As a consequence the simulated emission of BVOCs depends on the applied land cover map. To test the sensitivity of global and regional estimates of BVOC emissions on the applied land cover map we applied 3 different land cover maps into our global aerosol-climate model ECHAM6-HAM2.2. We found a high sensitivity for tropical regions. BVOCs are a very prominent precursor for the production of Secondary Organic Aerosols (SOA). Therefore the sensitivity of BVOC emissions on land cover maps impacts the SOA burden in the atmosphere. With our model system we are able to quantify that impact. References: Guenther et al. (2006), Estimates of global terrestrial isoprene emissions using MEGAN, Atmos. Chem. Phys., 6, 3181-3210, doi:10.5194/acp-6-3181-2006. Jung et al. (2006), Exploiting synergies of global land cover products for carbon cycle modeling, Rem. Sens. Environm., 101, 534-553, doi:10.1016/j.rse.2006.01.020.

  15. Enhancement of aerosol responses to changes in emissions over East Asia by gas-oxidant-aerosol coupling and detailed aerosol processes

    NASA Astrophysics Data System (ADS)

    Matsui, H.; Koike, M.

    2016-06-01

    We quantify the responses of aerosols to changes in emissions (sulfur dioxide, black carbon (BC), primary organic aerosol, nitrogen oxides (NOx), and volatile organic compounds) over East Asia by using simulations including gas-oxidant-aerosol coupling, organic aerosol (OA) formation, and BC aging processes. The responses of aerosols to NOx emissions are complex and are dramatically changed by simulating gas-phase chemistry and aerosol processes online. Reduction of NOx emissions by 50% causes a 30-40% reduction of oxidant (hydroxyl radical and ozone) concentrations and slows the formation of sulfate and OA by 20-30%. Because the response of OA to changes in NOx emissions is sensitive to the treatment of emission and oxidation of semivolatile and intermediate volatility organic compounds, reduction of the uncertainty in these processes is necessary to evaluate gas-oxidant-aerosol coupling accurately. Our simulations also show that the sensitivity of aerosols to changes in emissions is enhanced by 50-100% when OA formation and BC aging processes are resolved in the model. Sensitivity simulations show that the increase of NOx emissions from 1850 to 2000 explains 70% (40%) of the enhancement of aerosol mass concentrations (direct radiative effects) over East Asia during that period through enhancement of oxidant concentrations and that this estimation is sensitive to the representation of OA formation and BC aging processes. Our results demonstrate the importance of simultaneous simulation of gas-oxidant-aerosol coupling and detailed aerosol processes. The impact of NOx emissions on aerosol formation will be a key to formulating effective emission reduction strategies such as BC mitigation and aerosol reduction policies in East Asia.

  16. Spectroscopic Study of Methylglyoxal and its Hydrates : a Gaseous Precursor of Secondary Organic Aerosols.

    NASA Astrophysics Data System (ADS)

    Bteich, Sabath; Goubet, Manuel; Margulès, L.; Motiyenko, R. A.; Huet, T. R.

    2016-06-01

    Secondary organic aerosols (SOA) have a significant effect on climate change. They are mainly produced in the atmosphere by oxidation of gaseous precursors. Fu et al. have suggested trans-methylglyoxal (MG) as a possible precursor of SOA in the cloud for its presence in large quantities in the atmosphere. The characterization of SOAs precursors by laboratory spectroscopy allows providing elements for the understanding of the process of formation of these aerosols. For this purpose, we completed the existing pure rotational spectrum of MG in the 12-40 GHz range by new records in a supersonic jet in the 4-20 GHz range (FTMW) and at room temperature in the 150-500 GHz range (mm/submm-wave spectrometer). The analysis was made with the support of quantum chemistry calculations (MP2/CBS and B98/CBS using the Gaussian 09 software). The adjustment of the spectroscopic parameters, taking into account the internal rotation related to the presence of a methyl group, was performed using the RAM36 code. The spectra have been reproduced at the experimental precision up to maximal values of J and K_a equal to 85 and 35, respectively. The data obtained for the isolated molecule, both experimentally and theoretically, will allow the study of its hydrated complexes and, by comparison, will give access to (micro-) hydration properties. For this purpose, two stable complexes predicted by theoretical calculations will be studied. T.- M. Fu et al., J. Geophys. Res., 113, (2008). C.E. Dyltick-Brenzinger and A. Bauder, Chem. Phys. 30, 147 (1978).

  17. Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations

    NASA Astrophysics Data System (ADS)

    Cui, H.; Mao, P.; Zhao, Y.; Nielsen, C. P.; Zhang, J.

    2015-03-01

    China is experiencing severe carbonaceous aerosol pollution driven mainly by large emissions resulting from intensive use of solid fuels. To gain a better understanding of the levels and trends of carbonaceous aerosol emissions and the resulting ambient concentrations at the national scale, we update an emission inventory of anthropogenic organic carbon (OC) and elemental carbon (EC) and employ existing observational studies to analyze characteristics of these aerosols including temporal, spatial, and size distributions, and the levels and shares of secondary organic carbon (SOC) in total OC. We further use ground observations to test the levels and inter-annual trends of the calculated national and provincial emissions of carbonaceous aerosols, and propose possible improvements in emission estimation for the future. The national OC emissions are estimated to have increased 29% from 2000 (2127 Gg) to 2012 (2749 Gg) and EC by 37% (from 1356 to 1857 Gg). The residential, industrial, and transportation sectors contributed an estimated 76 ± 2, 19 ± 2 and 5 ± 1% of the total emissions of OC, respectively, and 52 ± 3, 32 ± 2 and 16 ± 2% of EC. Updated emission factors based on the most recent local field measurements, particularly for biofuel stoves, lead to considerably lower emissions of OC compared to previous inventories. Compiling observational data across the country, higher concentrations of OC and EC are found in northern and inland cities, while larger OC/EC and SOC/OC ratios are found in southern cities, due to the joint effects of primary emissions and meteorology. Higher SOC/OC ratios are estimated at rural and remote sites compared to urban ones, attributed to more emissions of OC from biofuel use, more biogenic emissions of volatile organic compound (VOC) precursors to SOC, and/or transport of aged aerosols. For most sites, higher concentrations of OC, EC, and SOC are observed in colder seasons, while SOC/OC is reduced, particularly at rural and

  18. TOWARD AN EMPIRICAL THEORY OF PULSAR EMISSION. X. ON THE PRECURSOR AND POSTCURSOR EMISSION

    SciTech Connect

    Basu, Rahul; Mitra, Dipanjan; Rankin, Joanna M.

    2015-01-10

    Precursors and postcursors (PPCs) are rare emission components, which appear beyond the main pulse emission, in some cases far away from it, and are detected in a handful of pulsar. In this paper we attempt to characterize the PPC emission in relation to the pulsar main pulse geometry. In our analysis we find that PPC components have properties very different from that of outer conal emission. The separation of the PPC components from the main pulse center remains constant with frequency. In addition the beam opening angles corresponding to the separation of PPC components from the pulsar center are much larger than the largest encountered in conal emission. Pulsar radio emission is believed to originate within the magnetic polar flux tubes due to the growth of instabilities in the outflowing relativistic plasma. Observationally, there is strong evidence that the main pulse emission originates at altitudes of about 50 neutron star radii for a canonical pulsar. Currently, the most plausible radio emission model that can explain main pulse emission is the coherent curvature radiation mechanism, wherein relativistic charged solitons are formed in a non-stationary electron-positron-pair plasma. The wider beam opening angles of PPC require the emission to emanate from larger altitudes as compared to the main pulse, if both these components originate by the same emission mechanism. We explore this possibility and find that this emission mechanism is probably inapplicable at the height of the PPC emission. We propose that the PPC emission represents a new type of radiation from pulsars with a mechanism different from that of the main pulse.

  19. Patterns in atmospheric carbonaceous aerosols in China: emission estimates and observed concentrations

    NASA Astrophysics Data System (ADS)

    Cui, H.; Mao, P.; Zhao, Y.; Nielsen, C. P.; Zhang, J.

    2015-08-01

    China is experiencing severe carbonaceous aerosol pollution driven mainly by large emissions resulting from intensive use of solid fuels. To gain a better understanding of the levels and trends of carbonaceous aerosol emissions and the resulting ambient concentrations at the national scale, we update an emission inventory of anthropogenic organic carbon (OC) and elemental carbon (EC) and employ existing observational studies to analyze characteristics of these aerosols including temporal, spatial, and size distributions, and the levels and shares of secondary organic carbon (SOC) in total OC. We further use ground observations to test the levels and inter-annual trends of the calculated national and provincial emissions of carbonaceous aerosols, and propose possible improvements in emission estimation for the future. The national OC emissions are estimated to have increased 29 % from 2000 (2127 Gg) to 2012 (2749 Gg) and EC by 37 % (from 1356 to 1857 Gg). The residential, industrial, and transportation sectors contributed an estimated 74-78, 17-21, and 4-6 % of the total emissions of OC, respectively, and 49-55, 30-34, and 14-18 % of EC. Updated emission factors (EFs) based on the most recent local field measurements, particularly for biofuel stoves, led to considerably lower emissions of OC compared to previous inventories. Compiling observational data across the country, higher concentrations of OC and EC are found in northern and inland cities, while higher OC / EC ratios are found in southern sites, due to the joint effects of primary emissions and meteorology. Higher OC / EC ratios are estimated at rural and remote sites compared to urban ones, attributed to more emissions of OC from biofuel use, more biogenic emissions of volatile organic compound (VOC) precursors to SOC, and/or transport of aged aerosols. For most sites, higher concentrations of OC, EC, and SOC are observed in colder seasons, while SOC / OC is reduced, particularly at rural and remote sites

  20. Emissions of biogenic volatile organic compounds and subsequent formation of secondary organic aerosols in a Larix kaempferi forest

    NASA Astrophysics Data System (ADS)

    Mochizuki, T.; Miyazaki, Y.; Ono, K.; Wada, R.; Takahashi, Y.; Saigusa, N.; Kawamura, K.; Tani, A.

    2015-04-01

    We conducted simultaneous measurements of concentrations and above-canopy fluxes of isoprene and α-pinene, along with their oxidation products in aerosols in a Larix kaempferi (Japanese larch) forest in summer 2012. Vertical profiles of isoprene showed the maximum concentration near the forest floor with a peak around noon, whereas oxidation products of isoprene, i.e., methacrolein (MACR) and methyl vinyl ketone (MVK), showed higher concentrations near the canopy level of the forest. The vertical profile suggests large emissions of isoprene near the forest floor, likely due to Dryopteris crassirhizoma (a fern species), and the subsequent reaction within the canopy. The concentrations of α-pinene also showed highest values near the forest floor with maximums in the early morning and late afternoon. The vertical profiles of α-pinene suggest its large emissions from soil and litter in addition to emissions from L. kaempferi leaves at the forest site. Isoprene and its oxidation products in aerosols exhibited similar diurnal variations within the forest canopy, providing evidence for secondary organic aerosol (SOA) formation via oxidation of isoprene most likely emitted from the forest floor. Although high abundance of α-pinene was observed in the morning, its oxidation products in aerosols showed peaks in daytime, due to a time lag between the emission and atmospheric reactions of α-pinene to form SOA. Positive matrix factorization (PMF) analysis indicated that anthropogenic influence is the most important factor contributing to the elevated concentrations of molecular oxidation products of isoprene- (> 64%) and α-pinene-derived SOA (> 57%). The combination of the measured fluxes and vertical profiles of biogenic volatile organic compounds (BVOCs) suggests that the inflow of anthropogenic precursors/aerosols likely enhanced the formation of both isoprene- and α-pinene-SOA within the forest canopy even when the BVOC flux was relatively low. This study highlights

  1. Investigating the Precursor and Prompt Emission of Swift Gamma-Ray Bursts (GRBs)

    NASA Astrophysics Data System (ADS)

    Myers, B.; Stamatikos, M.

    2016-10-01

    We analyze the spectral lag, i.e. the arrival offset of high and low energy photons, for both the precursor and prompt emission of Swift-BAT GRBs, to probe if the precursor emission is an early activation of the progenitor's central engine activity.

  2. Gas phase emissions from cooking processes and their secondary aerosol production potential

    NASA Astrophysics Data System (ADS)

    Klein, Felix; Platt, Stephen; Bruns, Emily; Termime-roussel, Brice; Detournay, Anais; Mohr, Claudia; Crippa, Monica; Slowik, Jay; Marchand, Nicolas; Baltensperger, Urs; Prevot, Andre; El Haddad, Imad

    2014-05-01

    Long before the industrial evolution and the era of fossil fuels, high concentrations of aerosol particles were alluded to in heavily populated areas, including ancient Rome and medieval London. Recent radiocarbon measurements (14C) conducted in modern megacities came as a surprise: carbonaceous aerosol (mainly organic aerosol, OA), a predominant fraction of particulate matter (PM), remains overwhelmingly non-fossil despite extensive fossil fuel combustion. Such particles are directly emitted (primary OA, POA) or formed in-situ in the atmosphere (secondary OA, SOA) via photochemical reactions of volatile organic compounds (VOCs). Urban levels of non-fossil OA greatly exceed the levels measured in pristine environments strongly impacted by biogenic emissions, suggesting a contribution from unidentified anthropogenic non-fossil sources to urban OA. Positive matrix factorization (PMF) techniques applied to ambient aerosol mass spectrometer (AMS, Aerodyne) data identify primary cooking emissions (COA) as one of the main sources of primary non-fossil OA in major cities like London (Allan et al., 2010), New York (Sun et al., 2011) and Beijing (Huang et al., 2010). Cooking processes can also emit VOCs that can act as SOA precursors, potentially explaining in part the high levels of oxygenated OA (OOA) identified by the AMS in urban areas. However, at present, the chemical nature of these VOCs and their secondary aerosol production potential (SAPP) remain virtually unknown. The approach adopted here involves laboratory quantification of PM and VOC emission factors from the main primary COA emitting processes and their SAPP. Primary emissions from deep-fat frying, vegetable boiling, vegetable frying and meat cooking for different oils, meats and vegetables were analysed under controlled conditions after ~100 times dilution. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a high resolution proton transfer time-of-flight mass spectrometer (PTR

  3. Caribbean coral growth influenced by anthropogenic aerosol emissions

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, Lester; Cox, Peter M.; Economou, Theo; Halloran, Paul R.; Mumby, Peter J.; Booth, Ben B. B.; Carilli, Jessica; Guzman, Hector M.

    2013-05-01

    Coral growth rates are highly dependent on environmental variables such as sea surface temperature and solar irradiance. Multi-decadal variability in coral growth rates has been documented throughout the Caribbean over the past 150-200 years, and linked to variations in Atlantic sea surface temperatures. Multi-decadal variability in sea surface temperatures in the North Atlantic, in turn, has been linked to volcanic and anthropogenic aerosol forcing. Here, we examine the drivers of changes in coral growth rates in the western Caribbean between 1880 and 2000, using previously published coral growth chronologies from two sites in the region, and a numerical model. Changes in coral growth rates over this period coincided with variations in sea surface temperature and incoming short-wave radiation. Our model simulations show that variations in the concentration of anthropogenic aerosols caused variations in sea surface temperature and incoming radiation in the second half of the twentieth century. Before this, variations in volcanic aerosols may have played a more important role. With the exception of extreme mass bleaching events, we suggest that neither climate change from greenhouse-gas emissions nor ocean acidification is necessarily the driver of multi-decadal variations in growth rates at some Caribbean locations. Rather, the cause may be regional climate change due to volcanic and anthropogenic aerosol emissions.

  4. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols.

    PubMed

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-13

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  5. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  6. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    PubMed Central

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-01-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks. PMID:27733773

  7. Linking Load, Fuel, and Emission Controls to Photochemical Production of Secondary Organic Aerosol from a Diesel Engine.

    PubMed

    Jathar, Shantanu H; Friedman, Beth; Galang, Abril A; Link, Michael F; Brophy, Patrick; Volckens, John; Eluri, Sailaja; Farmer, Delphine K

    2017-02-07

    Diesel engines are important sources of fine particle pollution in urban environments, but their contribution to the atmospheric formation of secondary organic aerosol (SOA) is not well constrained. We investigated direct emissions of primary organic aerosol (POA) and photochemical production of SOA from a diesel engine using an oxidation flow reactor (OFR). In less than a day of simulated atmospheric aging, SOA production exceeded POA emissions by an order of magnitude or more. Efficient combustion at higher engine loads coupled to the removal of SOA precursors and particle emissions by aftertreatment systems reduced POA emission factors by an order of magnitude and SOA production factors by factors of 2-10. The only exception was that the retrofitted aftertreatment did not reduce SOA production at idle loads where exhaust temperatures were low enough to limit removal of SOA precursors in the oxidation catalyst. Use of biodiesel resulted in nearly identical POA and SOA compared to diesel. The effective SOA yield of diesel exhaust was similar to that of unburned diesel fuel. While OFRs can help study the multiday evolution, at low particle concentrations OFRs may not allow for complete gas/particle partitioning and bias the potential of precursors to form SOA.

  8. Emission of sunscreen salicylic esters from desert vegetation and their contribution to aerosol formation

    NASA Astrophysics Data System (ADS)

    Matsunaga, S. N.; Guenther, A. B.; Potosnak, M. J.; Apel, E. C.

    2008-12-01

    Biogenic volatile organic compounds (BVOC) produced by plants are known to have an important role in atmospheric chemistry. However, our knowledge of the range of BVOCs produced by different plant processes is still expanding, and there remain poorly understood categories of BVOCs. In this study, emissions of a novel class of BVOC emissions were investigated in a desert region. Our study considered 8 species of common desert plants: blackbrush (Coleogyne ramosissima), desert willow (Chilopsis linearis), mesquite (Prosopis glandulosa), mondel pine (Pinus eldarica), pinyon pine (Pinus monophylla), cottonwood (Populus deltoides), saguaro cactus (Carnegiea gigantea) and yucca (Yucca baccata). The measurements focused on BVOCs with relatively high molecular weight (>C15) and/or an oxygenated functional group. Significantly high emission rates of two salicylic esters were found for blackbrush, desert willow and mesquite with emission rates of 3.1, 1.0 and 4.8μgC dwg-1 h-1, respectively (dwg; dry weight of the leaves in gram). The salicylic esters were identified as 2-ethylhexenyl salicylate (2-EHS) and 3,3,5-trimethylcyclohexenyl salicylate (homosalate) and are known as effective ultraviolet (UV) absorbers. We propose that the plants derive a protective benefit against UV radiation from the salicylic esters and that the emission process is driven by the physical evaporation of the salicylic esters due to the high ambient temperatures. In addition, the salicylic esters are predicted to be an effective precursor of secondary organic aerosol (SOA) because they probably produce oxidation products that can condense onto the aerosol phase. We estimated the contribution of the sunscreen esters themselves and their oxidation products on the SOA formation for the Las Vegas area using a BVOC emission model. The contribution was estimated to reach 50% of the biogenic terpenoid emission in the landscapes dominated by desert willow and mesquite and 13% in the Las Vegas area. The

  9. Inorganic aerosols responses to emission changes in Yangtze River Delta, China.

    PubMed

    Dong, Xinyi; Li, Juan; Fu, Joshua S; Gao, Yang; Huang, Kan; Zhuang, Guoshun

    2014-05-15

    The new Chinese National Ambient Air Quality standards (CH-NAAQS) published on Feb. 29th, 2012 listed PM2.5 as criteria pollutant for the very first time. In order to probe into PM2.5 pollution over Yangtze River Delta, the integrated MM5/CMAQ modeling system is applied for a full year simulation to examine the PM2.5 concentration and seasonality, and also the inorganic aerosols responses to precursor emission changes. Total PM2.5 concentration over YRD was found to have strong seasonal variation with higher values in winter months (up to 89.9 μg/m(3) in January) and lower values in summer months (down to 28.8 μg/m(3) in July). Inorganic aerosols were found to have substantial contribution to PM2.5 over YRD, ranging from 37.1% in November to 52.8% in May. Nocturnal production of nitrate (NO3(-)) through heterogeneous hydrolysis of N2O5 was found significantly contribute to high NO3(-) concentration throughout the year. In winter, NO3(-) was found to increase under nitrogen oxides (NOx) emission reduction due to higher production of N2O5 from the excessive ozone (O3) introduced by attenuated titration, which further lead to increase of ammonium (NH4(+)) and sulfate (SO4(2-)), while other seasons showed decrease response of NO3(-). Sensitivity responses of NO3(-) under anthropogenic VOC emission reduction was examined and demonstrated that in urban areas over YRD, NO3(-) formation was actually more sensitive to VOC than NOx due to the O3-involved nighttime chemistry of N2O5, while a reduction of NOx emission may have counter-intuitive effect by increasing concentrations of inorganic aerosols.

  10. Inorganic aerosols responses to emission changes in Yangtze River Delta, China

    SciTech Connect

    Dong, Xinyi; Li, Juan; Fu, Joshua S.; Gao, Yang; Huang, Kan; Zhuang, Guoshun

    2014-05-15

    China announced the Chinese National Ambient Air Quality standards (CH-NAAQS) on Feb. 29th, 2012, and PM2.5 is for the very first time included in the standards as a criteria pollutant. In order to probe into PM2.5 pollution over Yangtze River Delta, which is one of the major urban clusters hosting more than 80 million people in China, the integrated MM5/CMAQ modeling system is applied for a full year simulation to examine the PM2.5 concentration and seasonality, and also the inorganic aerosols responses to precursor emission changes. Both simulation and observation demonstrated that, inorganic aerosols have substantial contributions to PM2.5 over YRD, ranging from 37.1% in November to 52.8% in May. Nocturnal production of nitrate (NO3-) through heterogeneous hydrolysis of N2O5 was found significantly contribute to high NO3-concentration throughout the year. We also found that in winter NO3- was even increased under nitrogen oxides (NOx) emission reduction due to higher production of N2O5 from the excessive ozone (O3) introduced by attenuated titration, which further lead to increase of ammonium (NH4+) and sulfate (SO42-), while other seasons showed decrease response of NO3-. Sensitivity responses of NO3- under anthropogenic VOC emission reduction was examined and demonstrated that in urban areas over YRD, NO3- formation was actually VOC sensitive due to the O3-involved nighttime chemistry of N2O5, while a reduction of NOx emission may have counter-intuitive effect by increasing concentrations of inorganic aerosols.

  11. Secondary organic aerosol formation exceeds primary particulate matter emissions for light-duty gasoline vehicles

    NASA Astrophysics Data System (ADS)

    Gordon, T. D.; Presto, A. A.; May, A. A.; Nguyen, N. T.; Lipsky, E. M.; Donahue, N. M.; Gutierrez, A.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

    2014-05-01

    The effects of photochemical aging on emissions from 15 light-duty gasoline vehicles were investigated using a smog chamber to probe the critical link between the tailpipe and ambient atmosphere. The vehicles were recruited from the California in-use fleet; they represent a wide range of model years (1987 to 2011), vehicle types and emission control technologies. Each vehicle was tested on a chassis dynamometer using the unified cycle. Dilute emissions were sampled into a portable smog chamber and then photochemically aged under urban-like conditions. For every vehicle, substantial secondary organic aerosol (SOA) formation occurred during cold-start tests, with the emissions from some vehicles generating as much as 6 times the amount of SOA as primary particulate matter (PM) after 3 h of oxidation inside the chamber at typical atmospheric oxidant levels (and 5 times the amount of SOA as primary PM after 5 × 106 molecules cm-3 h of OH exposure). Therefore, the contribution of light-duty gasoline vehicle exhaust to ambient PM levels is likely dominated by secondary PM production (SOA and nitrate). Emissions from hot-start tests formed about a factor of 3-7 less SOA than cold-start tests. Therefore, catalyst warm-up appears to be an important factor in controlling SOA precursor emissions. The mass of SOA generated by photooxidizing exhaust from newer (LEV2) vehicles was a factor of 3 lower than that formed from exhaust emitted by older (pre-LEV) vehicles, despite much larger reductions (a factor of 11-15) in nonmethane organic gas emissions. These data suggest that a complex and nonlinear relationship exists between organic gas emissions and SOA formation, which is not surprising since SOA precursors are only one component of the exhaust. Except for the oldest (pre-LEV) vehicles, the SOA production could not be fully explained by the measured oxidation of speciated (traditional) SOA precursors. Over the timescale of these experiments, the mixture of organic vapors

  12. Secondary organic aerosol formation exceeds primary particulate matter emissions for light-duty gasoline vehicles

    NASA Astrophysics Data System (ADS)

    Gordon, T. D.; Presto, A. A.; May, A. A.; Nguyen, N. T.; Lipsky, E. M.; Donahue, N. M.; Gutierrez, A.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

    2013-09-01

    The effects of photochemical aging on emissions from 15 light-duty gasoline vehicles were investigated using a smog chamber to probe the critical link between the tailpipe and ambient atmosphere. The vehicles were recruited from the California in-use fleet; they represent a wide range of model years (1987 to 2011), vehicle types and emission control technologies. Each vehicle was tested on a chassis dynamometer using the unified cycle. Dilute emissions were sampled into a portable smog chamber and then photochemically aged under urban-like conditions. For every vehicle, substantial secondary organic aerosol (SOA) formation occurred during cold-start tests, with the emissions from some vehicles generating as much as 6 times the amount of SOA as primary particulate matter after three hours of oxidation inside the chamber at typical atmospheric oxidant levels. Therefore, the contribution of light duty gasoline vehicle exhaust to ambient PM levels is likely dominated by secondary PM production (SOA and nitrate). Emissions from hot-start tests formed about a factor of 3-7 less SOA than cold-start tests. Therefore, catalyst warm-up appears to be an important factor in controlling SOA precursor emissions. The mass of SOA generated by photo-oxidizing exhaust from newer (LEV1 and LEV2) vehicles was only modestly lower (38%) than that formed from exhaust emitted by older (pre-LEV) vehicles, despite much larger reductions in non-methane organic gas emissions. These data suggest that a complex and non-linear relationship exists between organic gas emissions and SOA formation, which is not surprising since SOA precursors are only one component of the exhaust. Except for the oldest (pre-LEV) vehicles, the SOA production could not be fully explained by the measured oxidation of speciated (traditional) SOA precursors. Over the time scale of these experiments, the mixture of organic vapors emitted by newer vehicles appear to be more efficient (higher yielding) in producing SOA than

  13. Epoxide as a precursor to secondary organic aerosol formation from isoprene photooxidation in the presence of nitrogen oxides.

    PubMed

    Lin, Ying-Hsuan; Zhang, Haofei; Pye, Havala O T; Zhang, Zhenfa; Marth, Wendy J; Park, Sarah; Arashiro, Maiko; Cui, Tianqu; Budisulistiorini, Sri Hapsari; Sexton, Kenneth G; Vizuete, William; Xie, Ying; Luecken, Deborah J; Piletic, Ivan R; Edney, Edward O; Bartolotti, Libero J; Gold, Avram; Surratt, Jason D

    2013-04-23

    Isoprene is a substantial contributor to the global secondary organic aerosol (SOA) burden, with implications for public health and the climate system. The mechanism by which isoprene-derived SOA is formed and the influence of environmental conditions, however, remain unclear. We present evidence from controlled smog chamber experiments and field measurements that in the presence of high levels of nitrogen oxides (NO(x) = NO + NO2) typical of urban atmospheres, 2-methyloxirane-2-carboxylic acid (methacrylic acid epoxide, MAE) is a precursor to known isoprene-derived SOA tracers, and ultimately to SOA. We propose that MAE arises from decomposition of the OH adduct of methacryloylperoxynitrate (MPAN). This hypothesis is supported by the similarity of SOA constituents derived from MAE to those from photooxidation of isoprene, methacrolein, and MPAN under high-NOx conditions. Strong support is further derived from computational chemistry calculations and Community Multiscale Air Quality model simulations, yielding predictions consistent with field observations. Field measurements taken in Chapel Hill, North Carolina, considered along with the modeling results indicate the atmospheric significance and relevance of MAE chemistry across the United States, especially in urban areas heavily impacted by isoprene emissions. Identification of MAE implies a major role of atmospheric epoxides in forming SOA from isoprene photooxidation. Updating current atmospheric modeling frameworks with MAE chemistry could improve the way that SOA has been attributed to isoprene based on ambient tracer measurements, and lead to SOA parameterizations that better capture the dependency of yield on NO(x).

  14. Epoxide as a precursor to secondary organic aerosol formation from isoprene photooxidation in the presence of nitrogen oxides

    PubMed Central

    Lin, Ying-Hsuan; Zhang, Haofei; Pye, Havala O. T.; Zhang, Zhenfa; Marth, Wendy J.; Park, Sarah; Arashiro, Maiko; Cui, Tianqu; Budisulistiorini, Sri Hapsari; Sexton, Kenneth G.; Vizuete, William; Xie, Ying; Luecken, Deborah J.; Piletic, Ivan R.; Edney, Edward O.; Bartolotti, Libero J.; Gold, Avram; Surratt, Jason D.

    2013-01-01

    Isoprene is a substantial contributor to the global secondary organic aerosol (SOA) burden, with implications for public health and the climate system. The mechanism by which isoprene-derived SOA is formed and the influence of environmental conditions, however, remain unclear. We present evidence from controlled smog chamber experiments and field measurements that in the presence of high levels of nitrogen oxides (NOx = NO + NO2) typical of urban atmospheres, 2-methyloxirane-2-carboxylic acid (methacrylic acid epoxide, MAE) is a precursor to known isoprene-derived SOA tracers, and ultimately to SOA. We propose that MAE arises from decomposition of the OH adduct of methacryloylperoxynitrate (MPAN). This hypothesis is supported by the similarity of SOA constituents derived from MAE to those from photooxidation of isoprene, methacrolein, and MPAN under high-NOx conditions. Strong support is further derived from computational chemistry calculations and Community Multiscale Air Quality model simulations, yielding predictions consistent with field observations. Field measurements taken in Chapel Hill, North Carolina, considered along with the modeling results indicate the atmospheric significance and relevance of MAE chemistry across the United States, especially in urban areas heavily impacted by isoprene emissions. Identification of MAE implies a major role of atmospheric epoxides in forming SOA from isoprene photooxidation. Updating current atmospheric modeling frameworks with MAE chemistry could improve the way that SOA has been attributed to isoprene based on ambient tracer measurements, and lead to SOA parameterizations that better capture the dependency of yield on NOx. PMID:23553832

  15. Experiment to Characterize Aircraft Volatile Aerosol and Trace-Species Emissions (EXCAVATE)

    NASA Technical Reports Server (NTRS)

    Anderson, B. E.; Branham, H.-S.; Hudgins, C. H.; Plant, J. V.; Ballenthin, J. O.; Miller, T. M.; Viggiano, A. A.; Blake, D. R.; Boudries, H.; Canagaratna, M.

    2005-01-01

    The Experiment to Characterize Aircraft Volatile and Trace Species Emissions (EXCAVATE) was conducted at Langley Research Center (LaRC) in January 2002 and focused upon assaying the production of aerosols and aerosol precursors by a modern commercial aircraft, the Langley B757, during ground-based operation. Remaining uncertainty in the postcombustion fate of jet fuel sulfur contaminants, the need for data to test new theories of particle formation and growth within engine exhaust plumes, and the need for observations to develop air quality models for predicting pollution levels in airport terminal areas were the primary factors motivating the experiment. NASA's Atmospheric Effects of Aviation Project (AEAP) and the Ultra Effect Engine Technology (UEET) Program sponsored the experiment which had the specific objectives of determining ion densities; the fraction of fuel S converted from S(IV) to S(VI); the concentration and speciation of volatile aerosols and black carbon; and gas-phase concentrations of long-chain hydrocarbon and PAH species, all as functions of engine power, fuel composition, and plume age.

  16. Using a global aerosol model adjoint to unravel the footprint of spatially-distributed emissions on cloud droplet number and cloud albedo

    NASA Astrophysics Data System (ADS)

    Karydis, V. A.; Capps, S. L.; Moore, R. H.; Russell, A. G.; Henze, D. K.; Nenes, A.

    2012-12-01

    The adjoints of the GEOS-Chem Chemical Transport Model and a comprehensive cloud droplet parameterization are coupled to study the sensitivity of cloud droplet number concentration (Nd) over US regions and Central Europe to global emissions of anthropogenic fine mode aerosol precursors. Simulations reveal that the Nd over the midwestern and southeastern US is mostly sensitive to SO2 emissions during August, and to NH3 emissions during February. Over the western US, Nd is mostly sensitivity to SO2 and primary organic aerosol emissions. In Central Europe, Nd is most sensitive to NH3 and NOx emissions. As expected, local emissions strongly affect Nd; long-range transport, however, is also important for the western US and Europe. Emissions changes projected for the year 2050 are estimated to have the largest impacts on cloud albedo and Nd over Central Europe during August (42% and 82% change, respectively) and western US during February (12% and 36.5% change, respectively).

  17. Carbon and Aerosol Emissions from Biomass Fires in Mexico

    NASA Astrophysics Data System (ADS)

    Hao, W. M.; Flores Garnica, G.; Baker, S. P.; Urbanski, S. P.

    2009-12-01

    Biomass burning is an important source of many atmospheric greenhouse gases and photochemically reactive trace gases. There are limited data available on the spatial and temporal extent of biomass fires and associated trace gas and aerosol emissions in Mexico. Biomass burning is a unique source of these gases and aerosols, in comparison to industrial and biogenic sources, because the locations of fires vary considerably both daily and seasonally and depend on human activities and meteorological conditions. In Mexico, the fire season starts in January and about two-thirds of the fires occur in April and May. The amount of trace gases and aerosols emitted by fires spatially and temporally is a major uncertainty in quantifying the impact of fire emissions on regional atmospheric chemical composition. To quantify emissions, it is necessary to know the type of vegetation, the burned area, the amount of biomass burned, and the emission factor of each compound for each ecosystem. In this study biomass burning experiments were conducted in Mexico to measure trace gas emissions from 24 experimental fires and wildfires in semiarid, temperate, and tropical ecosystems from 2005 to 2007. A range of representative vegetation types were selected for ground-based experimental burns to characterize fire emissions from representative Mexico fuels. A third of the country was surveyed each year, beginning in the north. The fire experiments in the first year were conducted in Chihuahua, Nuevo Leon, and Tamaulipas states in pine forest, oak forest, grass, and chaparral. The second-year fire experiments were conducted on pine forest, oak forest, shrub, agricultural, grass, and herbaceous fuels in Jalisco, Puebla, and Oaxaca states in central Mexico. The third-year experiments were conducted in pine-oak forests of Chiapas, coastal grass, and low subtropical forest on the Yucatan peninsula. FASS (Fire Atmosphere Sampling System) towers were deployed for the experimental fires. Each FASS

  18. Chemical composition of emissions from urban sources of fine organic aerosol

    SciTech Connect

    Hildemann, L.M.; Markowski, G.R.; Cass, G.R. )

    1991-04-01

    A dilution source sampling system was used to collect primary fine aerosol emissions from important sources of urban organic aerosol, including a boiler burning No. 2 fuel oil, a home fireplace, a fleet of catalyst-equipped and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat cooking operations. Alternative dilution sampling techniques were used to collect emissions from cigarette smoking and a roofing tar pot, and grab sample techniques were employed to characterize paved road dust, brake lining wear, and vegetative detritus. Organic aerosol constituted the majority of the fine aerosol mass emitted from many of the sources tested. Fine primary organic aerosol emissions within the heavily urbanized western portion of the Los Angeles Basin were determined to total 29.8 metric ton/day. Over 40% of these organic aerosol emissions are from anthropogenic pollution sources that are expected to emit contemporary (nonfossil) aerosol carbon, in good agreement with the available ambient monitoring data.

  19. Radio Emissions Precursors of Impulsive Phase of Solar Flares Recorded by CALLISTO-BR

    NASA Astrophysics Data System (ADS)

    Fernandes, Francisco; Cunha-Silva, Rafael; Galdino, Marcela; Sodré, Zuleika

    2016-07-01

    A solar flare consists in an eruptive process and involves a sudden release of energy generated by processes carried on from instabilities in the magnetic configuration at solar atmosphere, generating emissions at different wavelengths. Usually, the pre-flare phase presents an increasing of soft X-ray, ultraviolet and radio emissions. In this work, we present a survey of solar radio emission recorded in metric wavelengths (45 - 250 MHz) by CALLISTO-BR spectrograph, belong to the e-Callisto network, associated with pre-flare phase of solar X-rays flares. A sample of 281 radio emissions was analyzed, and 120 were identified as precursor emissions of X-rays flares. The main results of the statistics can be summarized as: (a) 55% of the precursor radio emissions start less than 60 minutes before the beginning of the associated X-ray flare and about 20% start less than 20 minutes before the X-ray emission; (b) 27% of flares with precursor emissions are classified as B class, 61% of C class, and less than 22% of M class. No precursors radio emissions were associated with X class flare; (c) about 42% of radio precursor emissions are of type III bursts and 33% have complex morphology, as drifting pulsating structures. Analysis of global emission trends recorded during the precursor phase of the C4.8 flare of February 15, 2011 (14:32-14:51 UT) is also presented. The occurrence of radio emission during the pre-impulsive phase of a solar flare suggests the presence of plasma turbulence in the active region, since during the impulsive phase, when the energy is released, occur the heating of the plasma and increasing of soft X-ray emission as identified in the event analyzed. The results are presented and discussed.

  20. Science verification of operational aerosol and cloud products for TROPOMI on Sentinel-5 precursor

    NASA Astrophysics Data System (ADS)

    Lelli, Luca; Gimeno-Garcia, Sebastian; Sanders, Abram; Sneep, Maarten; Rozanov, Vladimir V.; Kokhanvosky, Alexander A.; Loyola, Diego; Burrows, John P.

    2016-04-01

    With the approaching launch of the Sentinel-5 precursor (S-5P) satellite, scheduled by mid 2016, one preparatory task of the L2 working group (composed by the Institute of Environmental Physics IUP Bremen, the Royal Netherlands Meteorological Institute KNMI De Bilt, and the German Aerospace Center DLR Oberpfaffenhofen) has been the assessment of biases among aerosol and cloud products, that are going to be inferred by the respective algorithms from measurements of the platform's payload TROPOspheric Monitoring Instrument (TROPOMI). The instrument will measure terrestrial radiance with varying moderate spectral resolutions from the ultraviolet throughout the shortwave infrared. Specifically, all the operational and verification algorithms involved in this comparison exploit the sensitivity of molecular oxygen absorption (the A-band, 755-775 nm, with a resolution of 0.54 nm) to changes in optical and geometrical parameters of tropospheric scattering layers. Therefore, aerosol layer height (ALH) and thickness (AOT), cloud top height (CTH), thickness (COT) and albedo (CA) are the targeted properties. First, the verification of these properties has been accomplished upon synchronisation of the respective forward radiative transfer models for a variety of atmospheric scenarios. Then, biases against independent techniques have been evaluated with real measurements of selected GOME-2 orbits. Global seasonal bias assessment has been carried out for CTH, CA and COT, whereas the verification of ALH and AOT is based on the analysis of the ash plume emitted by the icelandic volcanic eruption Eyjafjallajökull in May 2010 and selected dust scenes off the Saharan west coast sensed by SCIAMACHY in year 2009.

  1. Emissions of Black Carbon Aerosols from Alaskan Boreal Forest Wildfires

    NASA Astrophysics Data System (ADS)

    Mouteva, G.; Fahrni, S. M.; Rogers, B. M.; Wiggins, E. B.; Santos, G.; Czimczik, C. I.; Randerson, J. T.

    2014-12-01

    Boreal wildfires are a major source of carbonaceous aerosols. Emissions from wildfires in Alaska represent ~ 33% of all open biomass combustion emissions of black carbon (BC) in the United States. BC contributes to atmospheric warming and accelerates melting of ice and snow. With fire frequency and burned area projected to increase in boreal regions, BC has the potential to become an important positive feedback to climate change. Quantifying the emissions, constraining the sources and better understanding the transportation patterns of BC to the polar regions are therefore critical for constraining the strength of this feedback. We present results from direct measurements of BC from wildfires in Alaska during the summer of 2013 collected as a part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) campaign. Fine aerosol particulate matter (PM2.5) was collected at two locations: Caribou-Poker Creek Research Watershed and Delta Junction Agricultural and Forestry Experimental Site. Using a Sunset OCEC analyzer, we separated BC from organic carbon aerosols, measured concentrations and analyzed the radiocarbon (14C) content with accelerator mass spectrometry. We also analyzed the total carbon (C) and nitrogen (N) elemental and stable isotope composition of the bulk PM2.5 with EA-IRMS. We compared the temporal dynamics of BC concentrations and isotopic composition with active fire/thermal anomaly information from MODIS. Our results show that boreal forest fire emissions in interior Alaska increased BC concentrations by up to an order of magnitude above background levels. The mean Δ14C value of fire-emitted BC was 120‰ with a range of +99‰ to +149‰ after correcting for contributions from background BC. This range was in good agreement with measurements of the depth of burn in soil organic carbon layers from interior wildland fires, and Δ14C profiles. High fire periods also corresponded to elevated C:N ratios. The δ15N of the aerosols was

  2. Secondary Organic Aerosol Formation from Ultra-Low Super Ultra-Low and Partial Zero Emission Vehicle Exhaust

    NASA Astrophysics Data System (ADS)

    Robinson, A. L.; Zhao, Y.; Lambe, A. T.; Saleh, R.; Saliba, G.; Maldonado, H.; Sardar, S.; Frodin, B.; Drozd, G.; Goldstein, A. H.; Kroll, J. H.; Cross, E. S.; Franklin, J. P.

    2015-12-01

    Secondary organic aerosol (SOA) is the dominant component of organic aerosol in many urban areas during the summertime. On-road light duty gasoline vehicles (LDGV) have been indicated as a major source of SOA precursors. Emissions of the SOA-forming non methane hydrocarbons (NMHCs) from on-road LDGV have been substantially reduced along with more stringent emission standards, leading to reduced potential for SOA formation. However, recent smog chamber measurements reported that the reductions in SOA formation were less than those in NMHC emissions, indicating that newer, low emitting vehicles may emit a more efficient of SOA precursors. Vehicles that meet the ultra-low, super ultra-low and partial zero emission standards have substantially lower NMHC emissions than vehicles tested in past studies. To better understand the effects of more stringent emission controls on the SOA formation, we conducted experiments 13 vehicles recruited from the Southern California vehicle fleet (five ultra-low emission vehicles, four super ultra-low emission vehicles and four partial zero emission vehicles) at the California Air Resources Board Haagen-Smit Laboratory. In addition, we investigated several vehicles compliant with older emission standards have also been investigated here to bridge the previous studies. Dilute vehicle exhaust were photo-oxidized in a smog chamber with the VOC-to-NOx ratio adjusted to simulate the photochemistry in urban air. Application of literature data from single-ring aromatic compounds cannot explain the observed SOA during chamber experiments. The average ratios between estimated and measured SOA for vehicles under different emission standards ranged from 0.04 to 0.71. Comprehensive measurements of SOA precursor emissions were made, including NMHCs, intermediate volatility and semi-volatile organic compounds. This study presents results of SOA production from these low emitting vehicles and compares the results with recently published data. This

  3. Precursor gases of aerosols in the Mount St. Helens eruption plumes at stratospheric altitudes

    NASA Technical Reports Server (NTRS)

    Inn, E. C. Y.; Vedder, J. F.; Condon, E. P.; Ohara, D.

    1982-01-01

    Nineteen stratospheric samples from the eruption plumes of Mount St. Helens were collected in five flight experiments. The plume samples were collected at various altitudes from 13.1 to 20.7 km by using the Ames cryogenic sampling system on board the NASA U-2 aircraft. The enriched, cryogenically collected samples were analyzed by chromatography. The concentrations of aerosols precursor gases (OCS, SO2, and CS2), CH3Cl, N2O, CF2Cl2, and CFCl3 were measured by gas chromatography. Large enhancement of the mixing ratio of SO2 and moderate enhancement of CS2 and OCS were found in the plume samples compared with similar measurement under pre-volcanic conditions. A fast decay rate of the SO2 mixing ratio in the plume was observed. Measurement of Cl(-), SO2(2-), and NO3(-) by ion chromatography was also carried out on water solutions prepared from the plume samples. The results obtained with this technique imply large mixing ratios of HCl, (NO + NO2 + HNO3), and SO2, in which these constituents are the respective sources of the anions. Measurement of the Rn222 concentration in the plume was made. Other stratospheric constituents in the plume samples, such as H2O, CO2, CH4, and CO, were also observed.

  4. Soot aggregate restructuring due to coatings of secondary organic aerosol derived from aromatic precursors.

    PubMed

    Schnitzler, Elijah G; Dutt, Ashneil; Charbonneau, André M; Olfert, Jason S; Jäger, Wolfgang

    2014-12-16

    Restructuring of monodisperse soot aggregates due to coatings of secondary organic aerosol (SOA) derived from hydroxyl radical-initiated oxidation of toluene, p-xylene, ethylbenzene, and benzene was investigated in a series of photo-oxidation (smog) chamber experiments. Soot aggregates were generated by combustion of ethylene using a McKenna burner, treated by denuding, size-selected by a differential mobility analyzer, and injected into a smog chamber, where they were exposed to low vapor pressure products of aromatic hydrocarbon oxidation, which formed SOA coatings. Aggregate restructuring began once a threshold coating mass was reached, and the degree of the subsequent restructuring increased with mass growth factor. Although significantly compacted, fully processed aggregates were not spherical, with a mass-mobility exponent of 2.78, so additional SOA was required to fill indentations between collapsed branches of the restructured aggregates before the dynamic shape factor of coated particles approached 1. Trends in diameter growth factor, effective density, and dynamic shape factor with increasing mass growth factor indicate distinct stages in soot aggregate processing by SOA coatings. The final degree and coating mass dependence of soot restructuring were found to be the same for SOA coatings from all four aromatic precursors, indicating that the surface tensions of the SOA coatings are similar.

  5. Marine Primary and Secondary Aerosol emissions related to seawater biogeochemistry

    NASA Astrophysics Data System (ADS)

    Sellegri, Karine; D'Anna, Barbara; Marchand, Nicolas; Charriere, Bruno; Sempere, Richard; Mas, Sebastien; Schwier, Allison; Rose, Clémence; Pey, Jorge; Langley Dewitt, Helen; Même, Aurélie; R'mili, Badr; George, Christian; Delmont, Anne

    2014-05-01

    Marine aerosol contributes significantly to the global aerosol load and consequently has an important impact on both the Earth's albedo and climate. Different factors influence the way they are produced from the sea water and transferred to the atmosphere. The sea state (whitecap coverage) and sea temperature influence the size and concentration of primarily produced particles but also biogeochemical characteristics of the sea water may influence both the physical and chemical fluxes. In order to study marine emissions, one approach is to use semicontrolled environments such as mesocosms. Within the SAM project (Sources of marine Aerosol in the Mediterranean), we characterize the primary Sea Salt Aerosol (SSA) and Secondary aerosol formation by nucleation during mesocosms experiments performed in May 2013 at the Oceanographic and Marine Station STARESO in western Corsica. We followed both water and air characteristics of three mesocosms containing an immerged part filled with 3,3 m3 of sea water and an emerged part filled with filtered natural air. Mesocosms were equipped with a pack of optical and physicochemical sensors and received different treatments: one of these mesocosms was left unchanged as control and the two others were enriched by addition of nitrates and phosphates respecting Redfield ratio (N:P = 16) in order to create different levels of phytoplanctonic activities. The set of sensors in each mesocosm was allowed to monitor the water temperature, conductivity, pH, incident light, fluorescence of chlorophyll a, and dissolved oxygen concentration. The mesocosms waters were daily sampled for chemical and biological (dissolved organic matter (i.e. DOC and CDOM), particulate matter and related polar compounds, transparent polysaccharides and nutrients concentration) and biological (chlorophyll a, virus, bacteria, phytoplankton and zooplankton concentrations) analyses. Secondary new particle formation was followed on-line in the emerged parts of the

  6. Characterizing the influence of anthropogenic emissions and transport variability on sulfate aerosol concentrations at Mauna Loa Observatory

    NASA Astrophysics Data System (ADS)

    Potter, Lauren E.

    Sulfate aerosol in the atmosphere has substantial impacts on human health and environmental quality. Most notably, atmospheric sulfate has the potential to modify the earth's climate system through both direct and indirect radiative forcing mechanisms (Meehl et al., 2007). Emissions of sulfur dioxide, the primary precursor of sulfate aerosol, are now globally dominated by anthropogenic sources as a result of widespread fossil fuel combustion. Economic development in Asian countries since 1990 has contributed considerably to atmospheric sulfur loading, particularly China, which currently emits approximately 1/3 of global anthropogenic SO2 (Klimont et al., 2013). Observational and modeling studies have confirmed that anthropogenic pollutants from Asian sources can be transported long distances with important implications for future air quality and global climate change. Located in the remote Pacific Ocean (19.54°N, 155.58°W) at an elevation of 3.4 kilometers above sea level, Mauna Loa Observatory (MLO) is an ideal measurement site for ground-based, free tropospheric observations and is well situated to experience influence from springtime Asian outflow. This study makes use of a 14-year data set of aerosol ionic composition, obtained at MLO by the University of Hawaii at Manoa. Daily filter samples of total aerosol concentrations were made during nighttime downslope (free-tropospheric) transport conditions, from 1995 to 2008, and were analyzed for aerosol-phase concentrations of the following species: nitrate (NO3-), sulfate (SO42-), methanesulfonate (MSA), chloride (Cl-), oxalate, sodium (Na+), ammonium (NH 4+), potassium (K+), magnesium (Mg 2+), and calcium (Ca2+). An understanding of the factors controlling seasonal and interannual variations in aerosol speciation and concentrations at this site is complicated by the relatively short lifetimes of aerosols, compared with greenhouse gases which have also been sampled over long time periods at MLO. Aerosol filter

  7. Formation of brown carbon via reactions of ammonia with secondary organic aerosols from biogenic and anthropogenic precursors

    NASA Astrophysics Data System (ADS)

    Updyke, Katelyn M.; Nguyen, Tran B.; Nizkorodov, Sergey A.

    2012-12-01

    Filter samples of secondary organic aerosols (SOA) generated from the ozone (O3)- and hydroxyl radical (OH)-initiated oxidation of various biogenic (isoprene, α-pinene, limonene, α-cedrene, α-humulene, farnesene, pine leaf essential oils, cedar leaf essential oils) and anthropogenic (tetradecane, 1,3,5-trimethylbenzene, naphthalene) precursors were exposed to humid air containing approximately 100 ppb of gaseous ammonia (NH3). Reactions of SOA compounds with NH3 resulted in production of light-absorbing "brown carbon" compounds, with the extent of browning ranging from no observable change (isoprene SOA) to visible change in color (limonene SOA). The aqueous phase reactions with dissolved ammonium (NH4+) salts, such as ammonium sulfate, were equally efficient in producing brown carbon. Wavelength-dependent mass absorption coefficients (MAC) of the aged SOA were quantified by extracting known amounts of SOA material in methanol and recording its UV/Vis absorption spectra. For a given precursor, the OH-generated SOA had systematically lower MAC compared to the O3-generated SOA. The highest MAC values, for brown carbon from SOA resulting from O3 oxidation of limonene and sesquiterpenes, were comparable to MAC values for biomass burning particles but considerably smaller than MAC values for black carbon aerosols. The NH3/NH4+ + SOA brown carbon aerosol may contribute to aerosol optical density in regions with elevated concentrations of NH3 or ammonium sulfate and high photochemical activity.

  8. Unintended emission of nanoparticle aerosols during common laboratory handling operations.

    PubMed

    Gomez, Virginia; Irusta, Silvia; Balas, Francisco; Navascues, Nuria; Santamaria, Jesus

    2014-08-30

    Common laboratory operations such as pouring, mashing in an agate mortar, transferring with a spatula, have been assessed as potential sources for emission of engineered nanoparticles in simulated occupational environments. Also, the accidental spilling from an elevated location has been considered. For workplace operations, masses of 1500 or 500mg of three dry-state engineered nanoparticles (SiO2, TiO2 and Ce-TiO2) with all dimensions under 30nm, and one fibrous nanomaterial (MWCNT) with diameter under 10nm and length about 1.5μm were used. The measured number emission factors (NEF) for every operation and material in this work were in the range of 10(5) #s(-1). The traceability of emitted nanoparticles has been improved using Ce-doping on TiO2 nanoparticles. With this traceable material it was possible to show that generated aerosol nanoparticles are rapidly associated with background particles to form large-sized aerosol agglomerates.

  9. Characterization of Secondary Organic Aerosol Precursors Using Two-Dimensional Gas-Chromatography

    NASA Astrophysics Data System (ADS)

    Roskamp, M.; Lou, W.; Pankow, J. F.; Harley, P. C.; Turnipseed, A.; Barsanti, K. C.

    2012-12-01

    The oxidation of volatile organic compounds (VOCs) plays a role in both regional and global air quality. However, field and laboratory research indicate that the body of knowledge around the identities, quantities and oxidation processes of these compounds in the ambient atmosphere is still incomplete (e.g., Goldstein & Galbally, 2007; Robinson et al., 2009). VOCs emitted to the atmosphere largely are of biogenic origin (Guenther et al., 2006), and many studies of ambient secondary organic aerosol (SOA) suggest that SOA is largely of biogenic origin (albeit closely connected to anthropogenic activities, e.g., de Gouw and Jimenez, 2009). Accurate modeling of SOA levels and properties will require a more complete understanding of biogenic VOCs (BOCs) and their atmospheric oxidation products. For example, satellite measurements indicate that biogenic VOC emissions are two to three times greater than levels currently included in models (Heald et al., 2010). Two-dimensional gas chromatography (GC×GC) is a powerful analytical technique that shows much promise in advancing the state-of-knowledge regarding BVOCs and their role in SOA formation. In this work, samples were collected during BEACHON-RoMBAS (Bio-hydro-atmosphere Interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study) in July and August of 2011. The field site was a Ponderosa Pine forest near Woodland, CO, inside the Manitou Experimental Forest, which is operated by the US Forest Service. The area is characteristic of the central Rocky Mountains and trace gas monitoring indicates that little anthropogenic pollution is transported from the nearby urban areas (Kim et al. 2010 and references therein). Ambient and enclosure samples were collected on ATD (adsorption/thermal desorption) cartridges and analyzed for BVOCs using two-dimensional gas chromatography (GC×GC) with time of flight mass spectrometry (TOFMS) and flame ionized detection (FID). Measurements of

  10. Real-Time Observations of Secondary Aerosol Formation and Aging from Different Emission Sources and Environments

    NASA Astrophysics Data System (ADS)

    Ortega, A. M.; Palm, B. B.; Hayes, P. L.; Day, D. A.; Cubison, M.; Brune, W. H.; Hu, W.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Rappenglueck, B.; Bon, D.; Graus, M.; Warneke, C.; Gilman, J.; Kuster, W.; De Gouw, J. A.; Jimenez, J. L.

    2013-12-01

    To investigate atmospheric processing of direct urban and wildfire emissions, we deployed a photochemical flow reactor (Potential Aerosol Mass, PAM) with submicron aerosol size and chemical composition measurements during FLAME-3, a biomass-burning study at USDA Fire Sciences Laboratory in Missoula, MT, and CalNex, a field study investigating the nexus of air quality and climate change at a receptor site in the LA-Basin at Pasadena, CA. The reactor produces OH concentrations up to 4 orders of magnitude higher than in ambient air, achieving equivalent aging of ~2 weeks in 5 minutes of processing. The OH exposure (OHexp) was stepped every 20 min in both field studies. Results show the value of this approach as a tool for in-situ evaluation of changes in OA concentration and composition due to photochemical processing. In FLAME-3, the average OA enhancement factor was 1.42 × 0.36 of the initial POA. Reactive VOCs, such as toluene, monoterpenes, and acetaldehyde, decreased with increased OHexp; however, formic acid, acetone, and some unidentified OVOCs increased after significant exposure. Net SOA formation in the photochemical reactor increased with OHexp, typically peaking around 3 days of equivalent atmospheric photochemical age (OHexp ~3.9e11 molecules cm-3 s), then leveling off at higher exposures. Unlike other studies, no decrease in OA is observed at high exposure, likely due to lower max OHexp in this study due to very high OH reactivity. The amount of additional OA mass added from aging is positively correlated with initial POA concentration, but not with the total VOC concentration or the concentration of known SOA precursors. The mass of SOA formed often exceeded the mass of the known VOC precursors, indicating the likely importance of primary semivolatile/intermediate volatility species, and possibly of unidentified VOCs as SOA precursors in biomass burning smoke. Results from CalNex show enhancement of OA and inorganic aerosol from gas-phase precursors

  11. Emissions of biogenic volatile organic compounds and subsequent formation of secondary organic aerosols in a Larix kaempferi forest

    NASA Astrophysics Data System (ADS)

    Mochizuki, T.; Miyazaki, Y.; Ono, K.; Wada, R.; Takahashi, Y.; Saigusa, N.; Kawamura, K.; Tani, A.

    2015-10-01

    We conducted simultaneous measurements of concentrations and above-canopy fluxes of isoprene and α-pinene, along with their oxidation products in aerosols in a Larix kaempferi (Japanese larch) forest in summer 2012. Vertical profiles of isoprene showed the maximum concentration near the forest floor with a peak around noon, whereas oxidation products of isoprene, i.e., methacrolein (MACR) and methyl vinyl ketone (MVK), showed higher concentrations near the canopy level of the forest. The vertical profile suggests large emissions of isoprene near the forest floor, likely due to Dryopteris crassirhizoma (a fern species), and the subsequent reaction within the canopy. The concentrations of α-pinene also showed highest values near the forest floor, with maximums in the early morning and late afternoon. The vertical profiles of α-pinene suggest its large emissions from soil and litter in addition to emissions from L. kaempferi leaves at the forest site. Isoprene and its oxidation products in aerosols exhibited similar diurnal variations within the forest canopy, providing evidence of secondary organic aerosol (SOA) formation via oxidation of isoprene most likely emitted from the forest floor. Although high abundance of α-pinene was observed in the morning, its oxidation products in aerosols showed peaks in daytime, due to a time lag between the emission and atmospheric reactions of α-pinene to form SOA. Positive matrix factorization (PMF) analysis indicated that anthropogenic influence is the most important factor contributing to the elevated concentrations of molecular oxidation products of isoprene- (> 64 %) and α-pinene-derived SOA (> 57 %). The combination of the measured fluxes and vertical profiles of biogenic volatile organic compounds (BVOCs) suggests that the inflow of anthropogenic precursors/aerosols likely enhanced the formation of both isoprene SOA and α-pinene SOA within the forest canopy even when the BVOC flux was relatively low. This study

  12. Ammonia emissions in Europe, part II: How ammonia emission abatement strategies affect secondary aerosols

    NASA Astrophysics Data System (ADS)

    Backes, Anna M.; Aulinger, Armin; Bieser, Johannes; Matthias, Volker; Quante, Markus

    2016-02-01

    In central Europe, ammonium sulphate and ammonium nitrate make up a large fraction of fine particles which pose a threat to human health. Most studies on air pollution through particulate matter investigate the influence of emission reductions of sulphur- and nitrogen oxides on aerosol concentration. Here, we focus on the influence of ammonia (NH3) emissions. Emission scenarios have been created on the basis of the improved ammonia emission parameterization implemented in the SMOKE for Europe and CMAQ model systems described in part I of this study. This includes emissions based on future European legislation (the National Emission Ceilings) as well as a dynamic evaluation of the influence of different agricultural sectors (e.g. animal husbandry) on particle formation. The study compares the concentrations of NH3, NH4+, NO3 -, sulphur compounds and the total concentration of particles in winter and summer for a political-, technical- and behavioural scenario. It was found that a reduction of ammonia emissions by 50% lead to a 24% reduction of the total PM2.5 concentrations in northwest Europe. The observed reduction was mainly driven by reduced formation of ammonium nitrate. Moreover, emission reductions during winter had a larger impact than during the rest of the year. This leads to the conclusion that a reduction of the ammonia emissions from the agricultural sector related to animal husbandry could be more efficient than the reduction from other sectors due to its larger share in winter ammonia emissions.

  13. Transitions from functionalization to fragmentation reactions of laboratory secondary organic aerosol (SOA) generated from the OH oxidation of alkane precursors.

    PubMed

    Lambe, Andrew T; Onasch, Timothy B; Croasdale, David R; Wright, Justin P; Martin, Alexander T; Franklin, Jonathan P; Massoli, Paola; Kroll, Jesse H; Canagaratna, Manjula R; Brune, William H; Worsnop, Douglas R; Davidovits, Paul

    2012-05-15

    Functionalization (oxygen addition) and fragmentation (carbon loss) reactions governing secondary organic aerosol (SOA) formation from the OH oxidation of alkane precursors were studied in a flow reactor in the absence of NO(x). SOA precursors were n-decane (n-C10), n-pentadecane (n-C15), n-heptadecane (n-C17), tricyclo[5.2.1.0(2,6)]decane (JP-10), and vapors of diesel fuel and Southern Louisiana crude oil. Aerosol mass spectra were measured with a high-resolution time-of-flight aerosol mass spectrometer, from which normalized SOA yields, hydrogen-to-carbon (H/C) and oxygen-to-carbon (O/C) ratios, and C(x)H(y)+, C(x)H(y)O+, and C(x)H(y)O(2)+ ion abundances were extracted as a function of OH exposure. Normalized SOA yield curves exhibited an increase followed by a decrease as a function of OH exposure, with maximum yields at O/C ratios ranging from 0.29 to 0.74. The decrease in SOA yield correlates with an increase in oxygen content and decrease in carbon content, consistent with transitions from functionalization to fragmentation. For a subset of alkane precursors (n-C10, n-C15, and JP-10), maximum SOA yields were estimated to be 0.39, 0.69, and 1.1. In addition, maximum SOA yields correspond with a maximum in the C(x)H(y)O+ relative abundance. Measured correlations between OH exposure, O/C ratio, and H/C ratio may enable identification of alkane precursor contributions to ambient SOA.

  14. Satellite monitoring of trace gas and aerosol emissions during wildfires in Russia

    NASA Astrophysics Data System (ADS)

    Bondur, V. G.

    2016-12-01

    Peculiarities of the formation of carbon gas and fine aerosol emissions into the atmosphere during wildfires are analyzed. A prompt satellite monitoring system and technique for the assessment of burnt areas and volumes of CO2, CO, and PM2.5 emissions from wildfires are described. The results of satellite monitoring of the Russian Federation and some Russian regions for different months over 2010-2014 are given; burnt areas and volumes of carbon gas and aerosol emissions throughout the entire territory are assessed. The peculiarities of seasonal frequencies of wildfires and volumes of hazardous gas and fine aerosol emissions in the regions under study are identified.

  15. Experimental simulations of Titan's atmopshere : Detection of the precursors implied in the formation of aerosols

    NASA Astrophysics Data System (ADS)

    Bernard, J.-M.; Coll, P.; Jolly, A.; Bénilan, Y.; Cernogora, G.; Raulin, F.

    2003-04-01

    The atmospheric chemistry on Titan is reproduced during laboratory simulation experiments since several years. In order to simulate as well as possible Titan's atmosphere, these simulations are done by initiating a glow discharge in a continuously flowing N2/CH4 mixture at low temperature. Cold plasma at low pressure are used to simulate the photochemistry because the Electron Energy Distribution Function (EEDF) is close to the solar spectrum. The aim of the presented work is the in situ plasma study by a UV-visible Optical Emission Spectrometry and electrostatic probe measurements. The gas temperature is deduced from rotational nitrogen spectra, and the electric field from probe measurements. From the ratio E/N0 it is possible to calculate the EEDF. Moreover, the compounds (molecules/radicals/ions) evolution analysis in the reactor will allow the identification of those at the origin of the building of the solid phase, at gas/solid interface. From this work it could be possible to have a better knowledge of the formation of "tholins" considered to be an analogue of Titan's aerosols. We will present the first results obtained by emission spectroscopy, during experimental simulations of Titan's atmosphere. We will point out the detection of all the possible diatomic species made of C, N or H. We will also show the variation of their abundance as a function of the physico-chemical parameters of the discharge (temperature, pressure, percentage of methane in the initial gas mixture...). For example, the reactor immersion in a cryogenic fluid (liquid nitrogen) implies a noticeable change on the gas temperature and proves also the impact of this immersion to better simulate Titan's environment. These results will finally be compared to the C/N and C/H ratios determined in parallel in the solid phase produced in our experiments.

  16. Emission of sunscreen salicylic esters from desert vegetation and their contribution to aerosol formation

    NASA Astrophysics Data System (ADS)

    Matsunaga, S. N.; Guenther, A. B.; Potosnak, M. J.; Apel, E. C.

    2008-07-01

    Biogenic volatile organic compounds (BVOC) produced by plants are known to have an important role in atmospheric chemistry. However, our knowledge of the range of BVOCs produced by different plant processes is still expanding, and there remain poorly understood categories of BVOCs. In this study, emissions of a novel class of BVOC emissions were investigated in a desert region. Our study considered 8 species of common desert plants: blackbrush (Coleogyne ramosissima), desert willow (Chilopsis linearis), mesquite (Prosopis glandulosa), mondel pine (Pinus eldarica), pinyon pine (Pinus monophylla), cottonwood (Populus deltoides), saguaro cactus (Carnegiea gigantea) and yucca (Yucca baccata). The measurements focused on BVOCs with relatively high molecular weight (>C15) and/or an oxygenated functional group. Significantly high emission rates of two salicylic esters were found for blackbrush, desert willow and mesquite with emission rates of 1.4, 2.1 and 0.46 μgC dwg-1 h-1, respectively. The salicylic esters were identified as 2-ethylhexenyl salicylate (2-EHS) and 3,3,5-trimethylcyclohexenyl salicylate (homosalate) and are known as effective ultraviolet (UV) absorbers. We propose that the plants derive a protective benefit against UV radiation from the salicylic esters and that the emission process is driven by the physical evaporation of the salicylic esters due to the high ambient temperatures. In addition, the salicylic esters are predicted to be an effective precursor of secondary organic aerosol (SOA) because of their low vapor pressure due to a high number of carbon atoms (15 or 16) and the presence of three oxygen atoms. We estimated the contribution of the sunscreen esters themselves and their oxidation products on the SOA formation for the Las Vegas region using a BVOC emission model. The contribution was estimated to reach 90% of the biogenic SOA in the landscapes dominated by desert willow and mesquite and 25% in Las Vegas area.

  17. Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign.

    PubMed

    Collier, Sonya; Zhou, Shan; Onasch, Timothy B; Jaffe, Daniel A; Kleinman, Lawrence; Sedlacek, Arthur J; Briggs, Nicole L; Hee, Jonathan; Fortner, Edward; Shilling, John E; Worsnop, Douglas; Yokelson, Robert J; Parworth, Caroline; Ge, Xinlei; Xu, Jianzhong; Butterfield, Zachary; Chand, Duli; Dubey, Manvendra K; Pekour, Mikhail S; Springston, Stephen; Zhang, Qi

    2016-08-16

    Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (∼2700 m a.s.l.) as well as near their sources using an aircraft. The regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), an index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (∼1 h old) and emissions sampled after atmospheric transport (6-45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. These results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate.

  18. Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign

    DOE PAGES

    Collier, Sonya; Zhou, Shan; Onasch, Timothy B.; ...

    2016-07-11

    Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (~2700 m a.s.l.) as well as near their sources using an aircraft. In addition, the regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), anmore » index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (~1 h old) and emissions sampled after atmospheric transport (6–45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. In conclusion, these results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate.« less

  19. Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign

    SciTech Connect

    Collier, Sonya; Zhou, Shan; Onasch, Timothy B.; Jaffe, Daniel A.; Kleinman, Lawrence; Sedlacek, III, Arthur J.; Briggs, Nicole L.; Hee, Jonathan; Fortner, Edward; Shilling, John E.; Worsnop, Douglas; Yokelson, Robert J.; Parworth, Caroline; Ge, Xinlei; Xu, Jianzhong; Butterfield, Zachary; Chand, Duli; Dubey, Manvendra K.; Pekour, Mikhail S.; Springston, Stephen; Zhang, Qi

    2016-07-11

    Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, the regional and nearfield influences of wildfire emissions on ambient aerosol concentration and chemical properties in the Pacific Northwest region of the United States were studied using real-time measurements from a fixed ground site located in Central Oregon at the Mt. Bachelor Observatory (~2700 m a.s.l.) as well as near their sources using an aircraft. In addition, the regional characteristics of biomass burning aerosols were found to depend strongly on the modified combustion efficiency (MCE), an index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the oxidation state of organic aerosol increased with MCE and plume aging. The relationships between the aerosol properties and MCE were consistent between fresh emissions (~1 h old) and emissions sampled after atmospheric transport (6–45 h), suggesting that biomass burning organic aerosol concentration and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. In conclusion, these results suggest that MCE can be a useful metric for describing aerosol properties of wildfire emissions and their impacts on regional air quality and global climate.

  20. Measurement of elemental concentration of aerosols using spark emission spectroscopy.

    PubMed

    Diwakar, Prasoon K; Kulkarni, Pramod

    A coaxial microelectrode system has been used to collect and analyse the elemental composition of aerosol particles in near real-time using spark emission spectroscopy. The technique involves focused electrostatic deposition of charged aerosol particles onto the flat tip of a microelectrode, followed by introduction of spark discharge. A pulsed spark discharge was generated across the electrodes with input energy ranging from 50 to 300 mJ per pulse, resulting in the formation of controlled pulsed plasma. The particulate matter on the cathode tip is ablated and atomized by the spark plasma, resulting in atomic emissions which are subsequently recorded using a broadband optical spectrometer for element identification and quantification. The plasma characteristics were found to be very consistent and reproducible even after several thousands of spark discharges using the same electrode system. The spark plasma was characterized by measuring the excitation temperature (~7000 to 10 000 K), electron density (~10(16) cm(-3)), and evolution of spectral responses as a function of time. The system was calibrated using particles containing Pb, Si, Na and Cr. Absolute mass detection limits in the range 11 pg to 1.75 ng were obtained. Repeatability of spectral measurements varied from 2 to 15%. The technique offers key advantages over similar microplasma-based techniques such as laser-induced breakdown spectroscopy, as: (i) it does not require any laser beam optics and eliminates any need for beam alignment, (ii) pulse energy from dc power supply in SIBS system can be much higher compared to that from laser source of the same physical size, and (iii) it is quite conducive to compact, field-portable instrumentation.

  1. Measurement of elemental concentration of aerosols using spark emission spectroscopy†

    PubMed Central

    Diwakar, Prasoon K.

    2015-01-01

    A coaxial microelectrode system has been used to collect and analyse the elemental composition of aerosol particles in near real-time using spark emission spectroscopy. The technique involves focused electrostatic deposition of charged aerosol particles onto the flat tip of a microelectrode, followed by introduction of spark discharge. A pulsed spark discharge was generated across the electrodes with input energy ranging from 50 to 300 mJ per pulse, resulting in the formation of controlled pulsed plasma. The particulate matter on the cathode tip is ablated and atomized by the spark plasma, resulting in atomic emissions which are subsequently recorded using a broadband optical spectrometer for element identification and quantification. The plasma characteristics were found to be very consistent and reproducible even after several thousands of spark discharges using the same electrode system. The spark plasma was characterized by measuring the excitation temperature (~7000 to 10 000 K), electron density (~1016 cm−3), and evolution of spectral responses as a function of time. The system was calibrated using particles containing Pb, Si, Na and Cr. Absolute mass detection limits in the range 11 pg to 1.75 ng were obtained. Repeatability of spectral measurements varied from 2 to 15%. The technique offers key advantages over similar microplasma-based techniques such as laser-induced breakdown spectroscopy, as: (i) it does not require any laser beam optics and eliminates any need for beam alignment, (ii) pulse energy from dc power supply in SIBS system can be much higher compared to that from laser source of the same physical size, and (iii) it is quite conducive to compact, field-portable instrumentation. PMID:26491209

  2. Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the southeast United States and co-benefit of SO2 emission controls

    NASA Astrophysics Data System (ADS)

    Marais, E. A.; Jacob, D. J.; Jimenez, J. L.; Campuzano-Jost, P.; Day, D. A.; Hu, W.; Krechmer, J.; Zhu, L.; Kim, P. S.; Miller, C. C.; Fisher, J. A.; Travis, K.; Yu, K.; Hanisco, T. F.; Wolfe, G. M.; Arkinson, H. L.; Pye, H. O. T.; Froyd, K. D.; Liao, J.; McNeill, V. F.

    2016-02-01

    Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for isoprene SOA formation coupled to a detailed gas-phase isoprene oxidation scheme. The mechanism is based on aerosol reactive uptake coefficients (γ) for water-soluble isoprene oxidation products, including sensitivity to aerosol acidity and nucleophile concentrations. We apply this mechanism to simulation of aircraft (SEAC4RS) and ground-based (SOAS) observations over the southeast US in summer 2013 using the GEOS-Chem chemical transport model. Emissions of nitrogen oxides (NOx ≡ NO + NO2) over the southeast US are such that the peroxy radicals produced from isoprene oxidation (ISOPO2) react significantly with both NO (high-NOx pathway) and HO2 (low-NOx pathway), leading to different suites of isoprene SOA precursors. We find a mean SOA mass yield of 3.3 % from isoprene oxidation, consistent with the observed relationship of total fine organic aerosol (OA) and formaldehyde (a product of isoprene oxidation). Isoprene SOA production is mainly contributed by two immediate gas-phase precursors, isoprene epoxydiols (IEPOX, 58 % of isoprene SOA) from the low-NOx pathway and glyoxal (28 %) from both low- and high-NOx pathways. This speciation is consistent with observations of IEPOX SOA from SOAS and SEAC4RS. Observations show a strong relationship between IEPOX SOA and sulfate aerosol that we explain as due to the effect of sulfate on aerosol acidity and volume. Isoprene SOA concentrations increase as NOx emissions decrease (favoring the low-NOx pathway for isoprene oxidation), but decrease more strongly as SO2 emissions decrease (due to the effect of sulfate on aerosol acidity and volume). The US Environmental Protection Agency (EPA) projects 2013-2025 decreases in anthropogenic emissions of

  3. Anomalous radon emission as precursor of medium to strong earthquakes

    NASA Astrophysics Data System (ADS)

    Zoran, Maria

    2016-03-01

    Anomalous radon (Rn222) emissions enhanced by forthcoming earthquakes is considered to be a precursory phenomenon related to an increased geotectonic activity in seismic areas. Rock microfracturing in the Earth's crust preceding a seismic rupture may cause local surface deformation fields, rock dislocations, charged particle generation and motion, electrical conductivity changes, radon and other gases emission, fluid diffusion, electrokinetic, piezomagnetic and piezoelectric effects as well as climate fluctuations. Space-time anomalies of radon gas emitted in underground water, soil and near the ground air weeks to days in the epicentral areas can be associated with the strain stress changes that occurred before the occurrence of medium and strong earthquakes. This paper aims to investigate temporal variations of radon concentration levels in air near or in the ground by the use of solid state nuclear track detectors (SSNTD) CR-39 and LR-115 in relation with some important seismic events recorded in Vrancea region, Romania.

  4. Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios

    NASA Astrophysics Data System (ADS)

    Glotfelty, Timothy; Zhang, Yang; Karamchandani, Prakash; Streets, David G.

    2016-08-01

    The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O3 level and of 0.3 μg m-3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO2, H2O2, and the nitrate radical and increasing the atmosphere's near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O3, and increases in CH4 and VOCs. Increasing NOx and O3 levels enhances the nitrogen and O3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth's surface with a global average reduction in shortwave radiation of 1.2 W m-2. This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR's CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed

  5. Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios

    SciTech Connect

    Glotfelty, Timothy; Zhang, Yang; Karamchandani, Prakash; Streets, David G.

    2016-08-01

    The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O3 level and of 0.3 mg m3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO2, H2O2, and the nitrate radical and increasing the atmosphere’s near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O3, and increases in CH4 and VOCs. Increasing NOx and O3 levels enhances the nitrogen and O3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth’s surface with a global average reduction in shortwave radiation of 1.2 W m2 . This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR’s CCSM simulation, which does not include the advanced chemistry and aerosol

  6. Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign

    SciTech Connect

    Collier, Sonya; Zhou, Shan; Onasch, Timothy B.; Jaffe, Daniel A.; Kleinman, Lawrence; Sedlacek, Arthur J.; Briggs, Nicole L.; Hee, Jonathan; Fortner, Edward; Shilling, John E.; Worsnop, Douglas; Yokelson, Robert J.; Parworth, Caroline; Ge, Xinlei; Xu, Jianzhong; Butterfield, Zachary; Chand, Duli; Dubey, Manvendra K.; Pekour, Mikhail S.; Springston, Stephen; Zhang, Qi

    2016-08-16

    Abstract Wildfires are important contributors to atmospheric aerosols and a large source of emissions that impact regional air quality and global climate. In this study, wildfire emissions in the Pacific Northwest region of the United States were characterized using real-time measurements near their sources using an aircraft, and farther downwind from a fixed ground site located at the Mt. Bachelor Observatory (~ 2700 m a.s.l.). The characteristics of aerosol emissions were found to depend strongly on the modified combustion efficiency (MCE), a qualitative index of the combustion processes of a fire. Organic aerosol emissions had negative correlations with MCE, whereas the carbon oxidation state of organic aerosol increased with MCE. The relationships between the aerosol properties and MCE were consistent between fresher emissions (~1 hour old) and emissions sampled after atmospheric transport (6 - 45 hours), suggesting that organic aerosol mass loading and chemical properties were strongly influenced by combustion processes at the source and conserved to a significant extent during regional transport. These results suggest that MCE can be a useful metric for describing aerosol properties of regionally transported wildfire emissions and their impacts on regional air quality and global climate.

  7. Potential of Aerosol Liquid Water to Facilitate Organic Aerosol Formation: Assessing Knowledge Gaps about Precursors and Partitioning.

    PubMed

    Sareen, Neha; Waxman, Eleanor M; Turpin, Barbara J; Volkamer, Rainer; Carlton, Annmarie G

    2017-03-06

    Isoprene epoxydiol (IEPOX), glyoxal, and methylglyoxal are ubiquitous water-soluble organic gases (WSOGs) that partition to aerosol liquid water (ALW) and clouds to form aqueous secondary organic aerosol (aqSOA). Recent laboratory-derived Setschenow (or salting) coefficients suggest glyoxal's potential to form aqSOA is enhanced by high aerosol salt molality, or "salting-in". In the southeastern U.S., aqSOA is responsible for a significant fraction of ambient organic aerosol, and correlates with sulfate mass. However, the mechanistic explanation for this correlation remains elusive, and an assessment of the importance of different WSOGs to aqSOA is currently missing. We employ EPA's CMAQ model to the continental U.S. during the Southern Oxidant and Aerosol Study (SOAS) to compare the potential of glyoxal, methylglyoxal, and IEPOX to partition to ALW, as the initial step toward aqSOA formation. Among these three studied compounds, IEPOX is a dominant contributor, ∼72% on average in the continental U.S., to potential aqSOA mass due to Henry's Law constants and molecular weights. Glyoxal contributes significantly, and application of the Setschenow coefficient leads to a greater than 3-fold model domain average increase in glyoxal's aqSOA mass potential. Methylglyoxal is predicted to be a minor contributor. Acid or ammonium - catalyzed ring-opening IEPOX chemistry as well as sulfate-driven ALW and the associated molality may explain positive correlations between SOA and sulfate during SOAS and illustrate ways in which anthropogenic sulfate could regulate biogenic aqSOA formation, ways not presently included in atmospheric models but relevant to development of effective control strategies.

  8. Dust aerosol emission over the Sahara during summertime from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations

    NASA Astrophysics Data System (ADS)

    Todd, Martin C.; Cavazos-Guerra, Carolina

    2016-03-01

    Dust aerosols are an important component of the climate system and a challenge to incorporate into weather and climate models. Information on the location and magnitude of dust emission remains a key information gap to inform model development. Inadequate surface observations ensure that satellite data remain the primary source of this information over extensive and remote desert regions. Here, we develop estimates of the relative magnitude of active dust emission over the Sahara desert based on data from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Utilising the unique vertical profile of aerosol characteristics provided by CALIOP our algorithm identifies emission from aerosol extinction and lidar backscatter in the near surface layers. From the long-term CALIOP archive of day and night-time orbits over 2006-13 we construct coarse resolution maps of a new dust emission index (DEI) for the Sahara desert during the peak summer dust season (June to September). The spatial structure of DEI indicates highest emission over a broad zone focused on the border regions of Southern Algeria, Northern Mali and northwest Niger, displaced substantially (∼7°) to the east of the mean maximum in satellite-derived aerosol optical depth. In this region night-time emission exceeds that during the day. The DEI maps substantially corroborate recently derived dust source frequency count maps based on back-tracking plumes in high temporal resolution SEVIRI imagery. As such, a convergence of evidence from multiple satellite data sources using independent methods provides an increasingly robust picture of Saharan dust emission sources. Various caveats are considered. As such, quantitative estimates of dust emission may require a synergistic combined multi-sensor analysis.

  9. Transient Climate Impacts for Scenarios of Aerosol Emissions from Asia: A Story of Coal versus Gas

    NASA Astrophysics Data System (ADS)

    Grandey, B. S.; Cheng, H.; Wang, C.

    2014-12-01

    Projections of anthropogenic aerosol emissions are uncertain. In Asia, it is possible that emissions may increase if business continues as usual, with economic growth driving an increase in coal burning. But it is also possible that emissions may decrease rapidly due to the widespread adoption of cleaner technology or a shift towards non-coal fuels, such as natural gas. In this study, the transient climate impacts of three aerosol emissions scenarios are investigated: an RCP4.5 (Representative Concentration Pathway 4.5) control; a scenario with reduced Asian anthropogenic aerosol emissions; and a scenario with enhanced Asian anthropogenic aerosol emissions. A coupled atmosphere-ocean configuration of CESM (Community Earth System Model), including CAM5 (Community Atmosphere Model version 5), is used. Enhanced Asian aerosol emissions are found to delay global mean warming by one decade at the end of the century. Aerosol-induced suppression of the East Asian and South Asian summer monsoon precipitation occurs. The enhanced Asian aerosol emissions also remotely impact precipitation in other parts of the world: over the Sahel, West African monsoon precipitation is suppressed; and over Australia, austral summer monsoon precipitation is enhanced. These remote impacts on precipitation are associated with a southward shift of the ITCZ. The aerosol-induced sea surface temperature (SST) response appears to play an important role in the precipitation changes over South Asia and Australia, but not over East Asia. These results indicate that energy production in Asia, through the consequent aerosol emissions and associated radiative effects, might significantly influence future climate both locally and globally.

  10. Impacts of Lowered Urban Air Temperatures on Precursor Emission and Ozone Air Quality.

    PubMed

    Taha, Haider; Konopacki, Steven; Akbari, Hashem

    1998-09-01

    Meteorological, photochemical, building-energy, and power plant simulations were performed to assess the possible precursor emission and ozone air quality impacts of decreased air temperatures that could result from implementing the "cool communities" concept in California's South Coast Air Basin (SoCAB). Two pathways are considered. In the direct pathway, a reduction in cooling energy use translates into reduced demand for generation capacity and, thus, reduced precursor emissions from electric utility power plants. In the indirect pathway, reduced air temperatures can slow the atmospheric production of ozone as well as precursor emission from anthropogenic and biogenic sources. The simulations suggest small impacts on emissions following implementation of cool communities in the SoCAB. In summer, for example, there can be reductions of up to 3% in NOx emissions from in-basin power plants. The photochemical simulations suggest that the air quality impacts of these direct emission reductions are small. However, the indirect atmospheric effects of cool communities can be significant. For example, ozone peak concentrations can decrease by up to 11% in summer and population-weighted exceedance exposure to ozone above the California and National Ambient Air Quality Standards can decrease by up to 11 and 17%, respectively. The modeling suggests that if these strategies are combined with others, such as mobile-source emission control, the improvements in ozone air quality can be substantial.

  11. Biogenic sulfur emissions and aerosols over the tropical South Atlantic: 3. Atmospheric dimethylsulfide, aerosols and cloud condensation nuclei

    NASA Astrophysics Data System (ADS)

    Andreae, Meinrat O.; Elbert, Wolfgang; de Mora, Stephen J.

    1995-06-01

    emission from marine plankton to sulfate aerosol and global climate.

  12. High-time resolved measurements of biogenic and anthropogenic secondary organic aerosol precursors and products in urban air

    NASA Astrophysics Data System (ADS)

    Flores, Rosa M.; Doskey, Paul V.

    2016-04-01

    Volatile organic compounds (VOCs), which are present in the atmosphere entirely in the gas phase are directly emitted by biogenic (~1089 Tg yr-1) and anthropogenic sources (~185 Tg yr-1). However, the sources and molecular speciation of intermediate VOCs (IVOCs), which are for the most part also present almost entirely in the gas phase, are not well characterized. The VOCs and IVOCs participate in reactions that form ozone and semivolatile OC (SVOC) that partition into the aerosol phase. Formation and evolution of secondary organic aerosol (SOA) are part of a complex dynamic process that depends on the molecular speciation and concentration of VOCs, IVOCs, primary organic aerosol (POA), and the level of oxidants (NO3, OH, O3). The current lack of understanding of OA properties and their impact on radiative forcing, ecosystems, and human health is partly due to limitations of models to predict SOA production on local, regional, and global scales. More accurate forecasting of SOA production requires high-temporal resolution measurement and molecular characterization of SOA precursors and products. For the subject study, the IVOCs and aerosol-phase organic matter were collected using the high-volume sampling technique and were analyzed by multidimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToFMS). The IVOCs included terpenes, terpenoids, n-alkanes, branched alkanes, isoprenoids, alkylbenzenes, cycloalkylbenzenes, PAH, alkyl PAH, and an unresolved complex mixture (UCM). Diurnal variations of OA species containing multiple oxygenated functionalities and selected SOA tracers of isorprene, α-pinene, toluene, cyclohexene, and n-dodecane oxidation were also quantified. The data for SOA precursor and oxidation products presented here will be useful for evaluating the ability of molecular-specific SOA models to forecast SOA production in and downwind of urban areas.

  13. Radiative effects of interannually varying vs. interannually invariant aerosol emissions from fires

    NASA Astrophysics Data System (ADS)

    Grandey, Benjamin S.; Lee, Hsiang-He; Wang, Chien

    2016-11-01

    Open-burning fires play an important role in the earth's climate system. In addition to contributing a substantial fraction of global emissions of carbon dioxide, they are a major source of atmospheric aerosols containing organic carbon, black carbon, and sulfate. These "fire aerosols" can influence the climate via direct and indirect radiative effects. In this study, we investigate these radiative effects and the hydrological fast response using the Community Atmosphere Model version 5 (CAM5). Emissions of fire aerosols exert a global mean net radiative effect of -1.0 W m-2, dominated by the cloud shortwave response to organic carbon aerosol. The net radiative effect is particularly strong over boreal regions. Conventionally, many climate modelling studies have used an interannually invariant monthly climatology of emissions of fire aerosols. However, by comparing simulations using interannually varying emissions vs. interannually invariant emissions, we find that ignoring the interannual variability of the emissions can lead to systematic overestimation of the strength of the net radiative effect of the fire aerosols. Globally, the overestimation is +23 % (-0.2 W m-2). Regionally, the overestimation can be substantially larger. For example, over Australia and New Zealand the overestimation is +58 % (-1.2 W m-2), while over Boreal Asia the overestimation is +43 % (-1.9 W m-2). The systematic overestimation of the net radiative effect of the fire aerosols is likely due to the non-linear influence of aerosols on clouds. However, ignoring interannual variability in the emissions does not appear to significantly impact the hydrological fast response. In order to improve understanding of the climate system, we need to take into account the interannual variability of aerosol emissions.

  14. Emission and Chemistry of Organic Carbon in the Gas and Aerosol Phase at a Sub-Urban Site Near Mexico City in March 2006 During the MILAGRO Study

    SciTech Connect

    de Gouw, Joost A.; Welsh-Bon, Daniel; Warneke, Carsten; Kuster, W. C.; Alexander, M. L.; Baker, Angela K.; Beyersdorf, Andreas J.; Blake, D. R.; Canagaratna, Manjula R.; Celada, A. T.; Huey, L. G.; Junkermann, W.; Onasch, Timothy B.; Salcido, A.; Sjostedt, S. J.; Sullivan, Amy; Tanner, David J.; Vargas-Ortiz, Leroy; Weber, R. J.; Worsnop, Douglas R.; Yu, Xiao-Ying; Zaveri, Rahul A.

    2009-05-28

    Volatile organic compounds (VOCs) and carbonaceous aerosol were measured at a sub-urban site near Mexico City in March of 2006 during the MILAGRO study (Megacity Initiative: Local and Global Research Objectives). Diurnal variations of hydrocarbons, elemental carbon (EC) and hydrocarbon-like organic aerosol (HOA) were dominated by a high peak in the early morning when local emissions accumulated in a shallow boundary layer, and a minimum in the afternoon when the emissions were diluted in a significantly expanded boundary layer and, in case of the reactive gases, removed by OH. In comparison, diurnal variations of species with secondary sources such as the aldehydes, ketones, oxygenated organic aerosol (OOA) and water-soluble organic carbon (WSOC) stayed relatively high in the afternoon indicating strong photochemical formation. Emission ratios of many hydrocarbon species relative to CO were higher in Mexico City than in the U.S., but we found similar emission ratios for most oxygenated VOCs and organic aerosol. Secondary formation of acetone may be more efficient in Mexico City than in the U.S., due to higher emissions of alkane precursors from the use of liquefied petroleum gas. Secondary formation of organic aerosol was similar between Mexico City and the U.S. Combining the data for all measured gas and aerosol species, we describe the budget of total observed organic carbon (TOOC), and find that the enhancement ratio of TOOC relative to CO is conserved between the early morning and mid afternoon despite large compositional changes. Finally, the influence of biomass burning is investigated using the measurements of acetonitrile, which was found to correlate with levoglucosan in the particle phase. Diurnal variations of acetonitrile indicate a contribution from local burning sources. Scatter plots of acetonitrile versus CO suggest that the contribution of biomass burning to the enhancement of most gas and aerosol species was not dominant and perhaps not dissimilar

  15. Secondary organic aerosol formation from photo-oxidation of unburned fuel: experimental results and implications for aerosol formation from combustion emissions.

    PubMed

    Jathar, Shantanu H; Miracolo, Marissa A; Tkacik, Daniel S; Donahue, Neil M; Adams, Peter J; Robinson, Allen L

    2013-11-19

    We conducted photo-oxidation experiments in a smog chamber to investigate secondary organic aerosol (SOA) formation from eleven different unburned fuels: commercial gasoline, three types of jet fuel, and seven different diesel fuels. The goals were to investigate the influence of fuel composition on SOA formation and to compare SOA production from unburned fuel to that from diluted exhaust. The trends in SOA production were largely consistent with differences in carbon number and molecular structure of the fuel, i.e., fuels with higher carbon numbers and/or more aromatics formed more SOA than fuels with lower carbon numbers and/or substituted alkanes. However, SOA production from different diesel fuels did not depend strongly on aromatic content, highlighting the important contribution of large alkanes to SOA formation from mixtures of high carbon number (lower volatility) precursors. In comparison to diesels, SOA production from higher volatility fuels such as gasoline appeared to be more sensitive to aromatic content. On the basis of a comparison of SOA mass yields (SOA mass formed per mass of fuel reacted) and SOA composition (as measured by an aerosol mass spectrometer) from unburned fuels and diluted exhaust, unburned fuels may be reasonable surrogates for emissions from uncontrolled engines but not for emissions from engines with after treatment devices such as catalytic converters.

  16. Measurement of the emission rate of an aerosol source--comparison of aerosol and gas transport coefficients.

    PubMed

    Bémer, D; Callé, S; Godinot, S; Régnier, R; Dessagne, J M

    2000-12-01

    A measuring method of the emission rate of an atmospheric pollutant source, based on the use of a tracer gas (helium) and developed in the case of a gaseous source, was tested for an aerosol source. The influence of both particle sedimentation and wall depositions was studied. The transport coefficients of the tracer gas and of alumina particles of various particle sizes (MMAD from 8 to 36 microns) were measured on a vertical axis close to the source, in a 71 m3 room swept by a piston flow. The measurements clearly demonstrated the predominant influence of sedimentation in the case of particles with aerodynamic diameters greater than 10 microns. Particle wall deposition was determined by measuring the gas and particle concentration decay in the ventilated room. To do this, a new tracing method using a fluorescent aerosol was developed. The measured aerosol deposition rates are much higher than those calculated from the formula of Corner for a cubical volume. Aerosol sedimentation and wall deposition are two phenomena limiting the use of a tracer gas to measure the aerosol emission rate. The chemical substances and materials used in work premises are likely to be released into the atmosphere and lead to the formation of pollutants. These emissions stem from either physical or chemical processes (evaporation of a solvent) or from mechanical processes (dispersion of oil droplets at the source of mists).

  17. Aerosol simulation applying high resolution anthropogenic emissions with the EMAC chemistry-climate model

    NASA Astrophysics Data System (ADS)

    Pozzer, A.; de Meij, A.; Pringle, K. J.; Tost, H.; Doering, U. M.; van Aardenne, J.; Lelieveld, J.

    2011-09-01

    The new high resolution global anthropogenic emission inventory (EDGAR-CIRCE) of gas and aerosol pollutants has been incorporated in the chemistry general circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry). A high horizontal resolution simulation is performed for the years 2005-2008 to evaluate the capability of the model and the emissions to reproduce observed aerosol concentrations and aerosol optical depth (AOD) values. Model output is compared with observations from different measurement networks (CASTNET, EMEP and EANET) and AODs from remote sensing instruments (MODIS and MISR). The model reproduces the main spatial and temporal atmospheric features of the sulfate, ammonium and nitrate aerosol distributions. A good spatial agreement of the distribution of sulfate and ammonium aerosol is found when compared to observations, while calculated nitrate aerosol concentrations show some discrepancies. The simulated temporal development of the inorganic aerosols is in line with measurements of sulfate and nitrate aerosol, while for ammonium aerosol some deviations from observations occur over the USA. The calculated AODs agree well with the satellite observations in most regions, while a negative bias is found for the equatorial area and in the dust outflow regions (i.e. Central Atlantic and Northern Indian Ocean), due to an underestimation of biomass burning and aeolian dust emissions, respectively.

  18. Aerosol exposure versus aerosol cooling of climate: what is the optimal emission reduction strategy for human health?

    NASA Astrophysics Data System (ADS)

    Löndahl, J.; Swietlicki, E.; Lindgren, E.; Loft, S.

    2010-10-01

    Particles, climate change, and health have thought-provoking interactions. Air pollution is one of the largest environmental problems concerning human health. On the other hand, aerosol particles can have a cooling effect on climate and a reduction of those emissions may result in an increased temperature globally, which in turn may have negative health effects. The objective of this work was to investigate the "total health effects" of aerosol emissions, which include both exposure to particles and consequences for climate change initiated by particles. As a case study the "total health effect" from ship emissions was derived by subtracting the number of deaths caused by exposure with the estimated number of lives saved from the cooling effect of the emissions. The analysis showed that, with current level of scientific understanding, it could not be determined whether ship emissions are negative or positive for human health on a short time scale. This first attempt to approximate the combined effect of particle emissions on health shows that reductions of particulate air pollution will in some cases (black carbon) have win-win effects on health and climate, but sometimes also cause a shift from particle exposure-related health effects towards an increasing risk of health consequences from climate change. Thus, measures to reduce aerosol emissions have to be coupled with climate change mitigation actions to achieve a full health benefit on a global level.

  19. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    NASA Astrophysics Data System (ADS)

    Strada, S.; Unger, N.

    2015-09-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (all anthropogenic, biomass burning and non-biomass burning) are investigated by performing sensitivity experiments. On the global scale, our results show that land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ~ 9 %. At the regional scale, plant productivity (GPP) and isoprene emission show a robust but opposite sensitivity to pollution aerosols, in regions where complex canopies dominate. In eastern North America and Europe, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +8-12 % on an annual average, with a stronger increase during the growing season (> 12 %). In the Amazon basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the Amazon basin during the dry-fire season (+5-8 %). In Europe and China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on the annual average. Anthropogenic aerosols affect land carbon fluxes via different mechanisms and we suggest that the dominant mechanism varies across regions: (1) light scattering dominates in the eastern US; (2) cooling in the Amazon basin; and (3) reduction in direct radiation in Europe and China.

  20. The use of ambient measurements to identify which precursor species limit aerosol nitrate formation.

    PubMed

    Blanchard, C L; Roth, P M; Tanenbaum, S J; Ziman, S D; Seinfeld, J H

    2000-12-01

    A thermodynamic equilibrium model was used to investigate the response of aerosol NO3 to changes in concentrations of HNO3, NH3, and H2SO4. Over a range of temperatures and relative humidities (RHs), two parameters provided sufficient information for indicating the qualitative response of aerosol NO3. The first was the excess of aerosol NH4+ plus gas-phase NH3 over the sum of HNO3, particulate NO3, and particulate SO4(2-) concentrations. The second was the ratio of particulate to total NO3 concentrations. Computation of these quantities from ambient measurements provides a means to rapidly analyze large numbers of samples and identify cases in which inorganic aerosol NO3 formation is limited by the availability of NH3. Example calculations are presented using data from three field studies. The predictions of the indicator variables and the equilibrium model are compared.

  1. Net radiative forcing due to changes in regional emissions of tropospheric ozone precursors

    NASA Astrophysics Data System (ADS)

    Naik, Vaishali; Mauzerall, Denise; Horowitz, Larry; Schwarzkopf, M. Daniel; Ramaswamy, V.; Oppenheimer, Michael

    2005-12-01

    The global distribution of tropospheric ozone (O3) depends on the emission of precursors, chemistry, and transport. For small perturbations to emissions, the global radiative forcing resulting from changes in O3 can be expressed as a sum of forcings from emission changes in different regions. Tropospheric O3 is considered in present climate policies only through the inclusion of indirect effect of CH4 on radiative forcing through its impact on O3 concentrations. The short-lived O3 precursors (NOx, CO, and NMHCs) are not directly included in the Kyoto Protocol or any similar climate mitigation agreement. In this study, we quantify the global radiative forcing resulting from a marginal reduction (10%) in anthropogenic emissions of NOx alone from nine geographic regions and a combined marginal reduction in NOx, CO, and NMHCs emissions from three regions. We simulate, using the global chemistry transport model MOZART-2, the change in the distribution of global O3 resulting from these emission reductions. In addition to the short-term reduction in O3, these emission reductions also increase CH4 concentrations (by decreasing OH); this increase in CH4 in turn counteracts part of the initial reduction in O3 concentrations. We calculate the global radiative forcing resulting from the regional emission reductions, accounting for changes in both O3 and CH4. Our results show that changes in O3 production and resulting distribution depend strongly on the geographical location of the reduction in precursor emissions. We find that the global O3 distribution and radiative forcing are most sensitive to changes in precursor emissions from tropical regions and least sensitive to changes from midlatitude and high-latitude regions. Changes in CH4 and O3 concentrations resulting from NOx emission reductions alone produce offsetting changes in radiative forcing, leaving a small positive residual forcing (warming) for all regions. In contrast, for combined reductions of anthropogenic

  2. Potential emission flux to aerosol pollutants over Bengal Gangetic plain through combined trajectory clustering and aerosol source fields analysis

    NASA Astrophysics Data System (ADS)

    Kumar, D. Bharath; Verma, S.

    2016-09-01

    A hybrid source-receptor analysis was carried out to evaluate the potential emission flux to winter monsoon (WinMon) aerosols over Bengal Gangetic plain urban (Kolkata, Kol) and semi-urban atmospheres (Kharagpur, Kgp). This was done through application of fuzzy c-mean clustering to back-trajectory data combined with emission flux and residence time weighted aerosols analysis. WinMon mean aerosol optical depth (AOD) and angstrom exponent (AE) at Kol (AOD: 0.77; AE: 1.17) were respectively slightly higher than and nearly equal to that at Kgp (AOD: 0.71; AE: 1.18). Out of six source region clusters over Indian subcontinent and two over Indian oceanic region, the cluster mean AOD was the highest when associated with the mean path of air mass originating from the Bay of Bengal and the Arabian sea clusters at Kol and that from the Indo-Gangetic plain (IGP) cluster at Kgp. Spatial distribution of weighted AOD fields showed the highest potential source of aerosols over the IGP, primarily over upper IGP (e.g. Punjab, Haryana), lower IGP (e.g. Uttarpradesh) and eastern region (e.g. west Bengal, Bihar, northeast India) clusters. The emission flux contribution potential (EFCP) of fossil fuel (FF) emissions at surface (SL) of Kol/Kgp, elevated layer (EL) of Kol, and of biomass burning (BB) emissions at SL of Kol were primarily from upper, lower, upper/lower IGP clusters respectively. The EFCP of FF/BB emissions at Kgp-EL/SL, and that of BB at EL of Kol/Kgp were mainly from eastern region and Africa (AFR) clusters respectively. Though the AFR cluster was constituted of significantly high emission flux source potential of dust emissions, the EFCP of dust from northwest India (NWI) was comparable to that from AFR at Kol SL/EL.

  3. Methods of analysis for complex organic aerosol mixtures from urban emission sources of particulate carbon

    SciTech Connect

    Mazurek, M.A. ); Hildemann, L.M. . Dept. of Civil Engineering); Cass, G.R.; Rogge, W.F. ); Simoneit, B.R.T. . Coll. of Oceanography)

    1990-10-01

    Organic aerosols comprise approximately 30% by mass of the total fine particulate matter present in urban atmospheres. The chemical composition of such aerosols is complex and reflects input from multiple sources of primary emissions to the atmosphere, as well as from secondary production of carbonaceous aerosol species via photochemical reactions. To identify discrete sources of fine carbonaceous particles in urban atmospheres, analytical methods must reconcile both bulk chemical and molecular properties of the total carbonaceous aerosol fraction. This paper presents an overview of the analytical protocol developed and used in a study of the major sources of fine carbon particles emitted to an urban atmosphere. 23 refs., 1 fig., 2 tabs.

  4. Radiative effects of interannually varying vs. interannually invariant aerosol emissions from fires

    DOE PAGES

    Grandey, Benjamin S.; Lee, Hsiang-He; Wang, Chien

    2016-11-23

    Open-burning fires play an important role in the earth's climate system. In addition to contributing a substantial fraction of global emissions of carbon dioxide, they are a major source of atmospheric aerosols containing organic carbon, black carbon, and sulfate. These “fire aerosols” can influence the climate via direct and indirect radiative effects. In this study, we investigate these radiative effects and the hydrological fast response using the Community Atmosphere Model version 5 (CAM5). Emissions of fire aerosols exert a global mean net radiative effect of −1.0 W m−2, dominated by the cloud shortwave response to organic carbon aerosol. The net radiative effect ismore » particularly strong over boreal regions. Conventionally, many climate modelling studies have used an interannually invariant monthly climatology of emissions of fire aerosols. However, by comparing simulations using interannually varying emissions vs. interannually invariant emissions, we find that ignoring the interannual variability of the emissions can lead to systematic overestimation of the strength of the net radiative effect of the fire aerosols. Globally, the overestimation is +23 % (−0.2 W m−2). Regionally, the overestimation can be substantially larger. For example, over Australia and New Zealand the overestimation is +58 % (−1.2 W m−2), while over Boreal Asia the overestimation is +43 % (−1.9 W m−2). The systematic overestimation of the net radiative effect of the fire aerosols is likely due to the non-linear influence of aerosols on clouds. However, ignoring interannual variability in the emissions does not appear to significantly impact the hydrological fast response. In order to improve understanding of the climate system, we need to take into account the interannual variability of aerosol emissions.« less

  5. Satellite Characterization of Fire Emissions of Aerosols and Gases Relevant to Air-Quality Modeling

    NASA Astrophysics Data System (ADS)

    Ichoku, C. M.; Ellison, L.; Yue, Y.; Wang, J.

    2015-12-01

    Because of the transient and widespread nature of wildfires and other types of open biomass burning, satellite remote sensing has become an indispensable technique for characterizing their smoke emissions for modeling applications, especially at regional to global scales. Fire radiative energy (FRE), whose instantaneous rate of release or fire radiative power (FRP) is measurable from space, has been found to be proportional to both the biomass consumption and emission of aerosol particulate matter. We have leveraged this relationship to generate a global, gridded smoke-aerosol emission coefficients (Ce) dataset based on FRP and aerosol optical thickness (AOT) measurements from the MODIS sensors aboard the Terra and Aqua satellites. Ce is a simple coefficient to convert FRE to smoke aerosol emissions, in the same manner as traditional emission factors are used to convert burned biomass to emissions. The first version of this Fire Energetics and Emissions Research (FEER.v1) global gridded Ce product at 1°x1° resolution is available at http://feer.gsfc.nasa.gov/. Based on published emission ratios, the FEER.v1 Ce product for total smoke aerosol has also been used to generate similar products for specific fire-emitted aerosols and gases, including those that are regulated as 'criteria pollutants' under the US Environmental Protection Agency's National Ambient Air Quality Standards (NAAQS), such as particulate matter (PM) and carbon monoxide (CO). These gridded Ce products were used in conjunction with satellite measurements of FRP to derive emissions of several smoke constituents, which were applied to WRF-Chem fully coupled meteorology-chemistry-aerosol model simulations, with promising results. In this presentation, we analyze WRF-Chem simulations of surface-level concentrations of various pollutants based on FEER.v1 emission products to illustrate their value for air-quality modeling, particularly in parts of Africa and southeast Asia where ground-based air

  6. Cloud-Resolving Model Simulations of Aerosol-Cloud Interactions Triggered by Strong Aerosol Emissions in the Arctic

    NASA Astrophysics Data System (ADS)

    Wang, H.; Kravitz, B.; Rasch, P. J.; Morrison, H.; Solomon, A.

    2014-12-01

    Previous process-oriented modeling studies have highlighted the dependence of effectiveness of cloud brightening by aerosols on cloud regimes in warm marine boundary layer. Cloud microphysical processes in clouds that contain ice, and hence the mechanisms that drive aerosol-cloud interactions, are more complicated than in warm clouds. Interactions between ice particles and liquid drops add additional levels of complexity to aerosol effects. A cloud-resolving model is used to study aerosol-cloud interactions in the Arctic triggered by strong aerosol emissions, through either geoengineering injection or concentrated sources such as shipping and fires. An updated cloud microphysical scheme with prognostic aerosol and cloud particle numbers is employed. Model simulations are performed in pure super-cooled liquid and mixed-phase clouds, separately, with or without an injection of aerosols into either a clean or a more polluted Arctic boundary layer. Vertical mixing and cloud scavenging of particles injected from the surface is still quite efficient in the less turbulent cold environment. Overall, the injection of aerosols into the Arctic boundary layer can delay the collapse of the boundary layer and increase low-cloud albedo. The pure liquid clouds are more susceptible to the increase in aerosol number concentration than the mixed-phase clouds. Rain production processes are more effectively suppressed by aerosol injection, whereas ice precipitation (snow) is affected less; thus the effectiveness of brightening mixed-phase clouds is lower than for liquid-only clouds. Aerosol injection into a clean boundary layer results in a greater cloud albedo increase than injection into a polluted one, consistent with current knowledge about aerosol-cloud interactions. Unlike previous studies investigating warm clouds, the impact of dynamical feedback due to precipitation changes is small. According to these results, which are dependent upon the representation of ice nucleation

  7. Unspeciated organic emissions from combustion sources and their influence on the secondary organic aerosol budget in the United States

    EPA Science Inventory

    Secondary organic aerosol (SOA) formed from the atmospheric oxidation of nonmethane organic gases (NMOG) is a major contributor to atmospheric aerosol mass. Emissions and smog chamber experiments were performed to investigate SOA formation from gasoline vehicles, diesel vehicles,...

  8. Effects of aerosol emission pathways on future warming and human health

    NASA Astrophysics Data System (ADS)

    Partanen, Antti-Ilari; Matthews, Damon

    2016-04-01

    The peak global temperature is largely determined by cumulative emissions of long-lived greenhouse gases. However, anthropogenic emissions include also so-called short-lived climate forcers (SLCFs), which include aerosol particles and methane. Previous studies with simple models indicate that the timing of SLCF emission reductions has only a small effect on the rate of global warming and even less of an effect on global peak temperatures. However, these simple model analyses do not capture the spatial dynamics of aerosol-climate interactions, nor do they consider the additional effects of aerosol emissions on human health. There is therefore merit in assessing how the timing of aerosol emission reductions affects global temperature and premature mortality caused by elevated aerosol concentrations, using more comprehensive climate models. Here, we used an aerosol-climate model ECHAM-HAMMOZ to simulate the direct and indirect radiative forcing resulting from aerosol emissions. We simulated Representative Concentration Pathway (RCP) scenarios, and we also designed idealized low and high aerosol emission pathways based on RCP4.5 scenario (LOW and HIGH, respectively). From these simulations, we calculated the Effective Radiative Forcing (ERF) from aerosol emissions between 1850 and 2100, as well as aerosol concentrations used to estimate the premature mortality caused by particulate pollution. We then use the University of Victoria Earth System Climate Model to simulate the spatial and temporal pattern of climate response to these aerosol-forcing scenarios, in combination with prescribed emissions of both short and long-lived greenhouse gases according to the RCP4.5 scenario. In the RCP scenarios, global mean ERF declined during the 21st century from -1.3 W m-2 to -0.4 W m-2 (RCP8.5) and -0.2 W m-2 (RCP2.6). In the sensitivity scenarios, the forcing at the end of the 21st century was -1.6 W m-2 (HIGH) and practically zero (LOW). The difference in global mean temperature

  9. Experimental Measurements of the Effects of Photo-chemical Oxidation on Aerosol Emissions in Aircraft Exhaust

    NASA Astrophysics Data System (ADS)

    Miracolo, M. A.; Presto, A. A.; Hennigan, C. J.; Nguyen, N.; Ranjan, M.; Reeder, A.; Lipsky, E.; Donahue, N. M.; Robinson, A. L.

    2009-12-01

    Many military and commercial airfields are located in non-attainment areas for particulate matter (PM2.5), but the contribution of emissions from in-use aircraft to local and regional PM2.5 concentrations is uncertain. In collaboration with the Pennsylvania Air National Guard 171st Air Refueling Wing, the Carnegie Mellon University (CMU) Mobile Laboratory was deployed to measure fresh and aged emissions from a CFM56-2B1 gas-turbine engine mounted on a KC-135 Stratotanker airframe. The CFM-56 family of engine powers many different types of military and civilian aircraft, including the Boeing 737 and several Airbus models. It is one of the most widely deployed models of engines in the world. The goal of this work was to measure the gas-particle partitioning of the fresh emissions at atmospherically relevant conditions and to investigate the effect of atmospheric oxidation on aerosol loadings as the emissions age. Emissions were sampled from an inlet installed one meter downstream of the engine exit plane and transferred into a portable smog chamber via a heated inlet line. Separate experiments were conducted at different engine loads ranging from ground idle to take-off rated thrust. During each experiment, some diluted exhaust was added to the chamber and the volatility of the fresh emissions was then characterized using a thermodenuder. After this characterization, the chamber was exposed to either ambient sunlight or UV lights to initiate photochemical oxidation, which produced secondary aerosol and ozone. A suite of gas and particle-phase instrumentation was used to characterize the evolution of the gas and particle-phase emissions, including an aerosol mass spectrometer (AMS) to measure particle size and composition distributions. Fresh emissions of fine particles varied with engine load with peak emission factors at low and high loads. At high engine loads, the fresh emissions were dominated by black carbon; at low loads volatile organic carbon emissions were

  10. Future Arctic temperature change resulting from a range of aerosol emissions scenarios

    NASA Astrophysics Data System (ADS)

    Wobus, Cameron; Flanner, Mark; Sarofim, Marcus C.; Moura, Maria Cecilia P.; Smith, Steven J.

    2016-06-01

    The Arctic temperature response to emissions of aerosols -- specifically black carbon (BC), organic carbon (OC), and sulfate -- depends on both the sector and the region where these emissions originate. Thus, the net Arctic temperature response to global aerosol emissions reductions will depend strongly on the blend of emissions sources being targeted. We use recently published equilibrium Arctic temperature response factors for BC, OC, and sulfate to estimate the range of present-day and future Arctic temperature changes from seven different aerosol emissions scenarios. Globally, Arctic temperature changes calculated from all of these emissions scenarios indicate that present-day emissions from the domestic and transportation sectors generate the majority of present-day Arctic warming from BC. However, in all of these scenarios, this warming is more than offset by cooling resulting from SO2 emissions from the energy sector. Thus, long-term climate mitigation strategies that are focused on reducing carbon dioxide (CO2) emissions from the energy sector could generate short-term, aerosol-induced Arctic warming. A properly phased approach that targets BC-rich emissions from the transportation sector as well as the domestic sectors in key regions -- while simultaneously working toward longer-term goals of CO2 mitigation -- could potentially avoid some amount of short-term Arctic warming.

  11. Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

    NASA Astrophysics Data System (ADS)

    Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

    2014-12-01

    Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or VOC / NOx ~3-9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast

  12. Secondary Organic Aerosol from On- and Off-Road Combustion Emissions: Scientific and Policy Perspectives

    NASA Astrophysics Data System (ADS)

    Gordon, Timothy D.

    Combustion emissions from on-road sources such as light duty gasoline vehicles (LDGV), medium duty diesel vehicles (MDDV) and heavy duty diesel vehicles (HDDV) as well as small off-road engines (SORE) such those used in lawn and garden equipment are a major source of fine particulate matter (PM) pollution in the ambient atmosphere. Existing regulations have restricted direct PM emissions, especially for on-road sources; however, recent studies suggest that organic PM formed from the photo-oxidation of gaseous precursor emissions—so-called secondary organic aerosol (SOA)—contributes at least as much to the overall PM burden as PM "emitted from the tailpipe." A major limitation of many of these studies is that they attempt to induce from the behavior of simple emission surrogates (e.g., vaporized whole fuel) the behavior of actual combustion emissions from real world sources. This research investigates combustion emissions directly. The primary gas- and particle-phase emissions, SOA production and SOA yields from a range of different on-road and off-road combustion sources were characterized. LDGV, MDDV and HDDV were driven on chassis dynamometers over realistic, urban driving cycles. Off-road sources, including 2- and 4-stroke lawn and garden equipment and a diesel transportation refrigeration unit were tested using engine dynamometers operated over certification cycles. For nearly all gasoline engines (LDGV and SOREs), photo-oxidizing dilute combustion emissions for 3 hours produced at least as much SOA as the directly emitted primary PM. SOA increased net PM production for LDGV by a factor of 1-10, depending on the vehicle emission standard. SOA yields were found to increase with newer vehicles, which have lower primary emissions. SOA for diesel vehicles, while still large on an absolute basis, was a smaller fraction of the primary PM emissions (between 10-30%), due to the very high elemental carbon (EC) emissions from vehicles without diesel particulate

  13. Effects of temperature on the formation of secondary organic aerosol from amine precursors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerosol formation is directly influenced by meteorological properties such as temperature and relative humidity. Temperature, for example, directly affects the gas-to-particle partitioning of amine salts and semi-volatile organic amine products. These salts are formed in areas with high agricultur...

  14. Laboratory studies of oxidation of primary emissions: Oxidation of organic molecular markers and secondary organic aerosol production

    NASA Astrophysics Data System (ADS)

    Weitkamp, Emily A.

    vehicle markers. Aerosol composition is a key influence on reaction rate constants, perhaps more significant than external influences. Alkenoic acid concentrations in the meat grease particles appear to influence cholesterol oxidation rates. Also, the reaction rate constants for new motor oil were faster than those of the more viscous used motor oil. The measured reaction rate constants were used to oxidize source profiles that were subsequently run in the Chemical Mass Balance (CMB) model. Oxidizing the molecular markers in the meat-cooking profile led to unrealistically high meat-cooking aerosol contributions to the total organic carbon (OC), often more than 100%. This suggests that there is either unaccounted for sources of meat-cooking molecular markers in the ambient samples, or there is some property of atmospheric aerosols that significantly inhibits reaction that was not captured in this study. Oxidation of motor vehicle profiles led to both higher estimates of total vehicle OC and a quadrupling of gasoline OC, while the diesel contribution changed very little. The increase in gasoline OC changes gasoline vehicle emissions from a relatively minor source to a major one. Thus, oxidation of molecular markers can have a significant impact on receptor model predictions. The second objective was to investigate SOA formation from the photo-oxidation of whole diesel exhaust. Diluted exhaust from a diesel engine was photo-oxidized in a smog chamber to investigate SOA production. Photochemical oxidation rapidly produced significant SOA, almost doubling the organic aerosol contribution of primary emissions after several hours of processing. Less than 10% of the SOA mass could be explained using a SOA model and the measured oxidation of known precursors, such as light aromatics. However, the ultimate yield of SOA is uncertain because it is sensitive to treatment of particle and vapor losses to the chamber walls. Aerosol Mass Spectrometer (AMS) mass spectra reveal that the

  15. Assessment of ozone and PM-10 precursor emissions from the dairy industry

    SciTech Connect

    Schmidt, C.E.; Ungvarsky, J.; Winegar, E.

    1997-12-31

    Many new regulations have resulted in the need to assess and better understand a variety of industries with air emission sources that have not been studied in the past. The dairy industry is one such industry with area air emission sources that are now being studied for evaluation and ranking with the intent to control air emissions that exceed regulatory acceptance standards, especially for ozone precursors. The area sources at a dairy include facility processes such as dry feed lot, flushed lanes, settling ponds, liquid waste storage, waste windrows, cow washing area, milk parlor, dry cow area birthing area, feed storage, and livestock waste fertilizer usage areas. Given that these processes are area sources and dynamic and highly variable, assessment requires proper selection of measurement technology and innovative applications. Direct assessment flux chamber technology was used to assess the air emissions from dairies located in northern California. All process were screened and evaluated for testing, and all significant air emission sources were studied. A variety of compounds were studied in order to satisfy program objectives, including: volatile organic compounds, semi-volatile organic compounds, amine, ammonia, reduced sulfur compounds, aldehydes, ketones, and fixed gases. Analytical development work extending applicability of methods, such as EPA TO-14 for semi-volatile compounds, assessing total content was also conducted. This paper presents a summary of the assessment approach used to gain a better understanding of air emissions from livestock waste at California dairies. Data are presented as emission factors (per surface area and per head) and as emissions from various size dairies. These data were used to evaluate ozone and PM-10 precursor emissions from the dairy industry.

  16. Potential sensitivity of photosynthesis and isoprene emission to direct radiative effects of atmospheric aerosol pollution

    NASA Astrophysics Data System (ADS)

    Strada, Susanna; Unger, Nadine

    2016-04-01

    A global Earth system model is applied to quantify the impacts of direct anthropogenic aerosol effective radiative forcing on gross primary productivity (GPP) and isoprene emission. The impacts of different pollution aerosol sources (anthropogenic, biomass burning, and non-biomass burning) are investigated by performing sensitivity experiments. The model framework includes all known light and meteorological responses of photosynthesis, but uses fixed canopy structures and phenology. On a global scale, our results show that global land carbon fluxes (GPP and isoprene emission) are not sensitive to pollution aerosols, even under a global decline in surface solar radiation (direct + diffuse) by ˜ 9 %. At a regional scale, GPP and isoprene emission show a robust but opposite sensitivity to pollution aerosols in regions where forested canopies dominate. In eastern North America and Eurasia, anthropogenic pollution aerosols (mainly from non-biomass burning sources) enhance GPP by +5-8 % on an annual average. In the northwestern Amazon Basin and central Africa, biomass burning aerosols increase GPP by +2-5 % on an annual average, with a peak in the northwestern Amazon Basin during the dry-fire season (+5-8 %). The prevailing mechanism varies across regions: light scattering dominates in eastern North America, while a reduction in direct radiation dominates in Europe and China. Aerosol-induced GPP productivity increases in the Amazon and central Africa include an additional positive feedback from reduced canopy temperatures in response to increases in canopy conductance. In Eurasia and northeastern China, anthropogenic pollution aerosols drive a decrease in isoprene emission of -2 to -12 % on an annual average. Future research needs to incorporate the indirect effects of aerosols and possible feedbacks from dynamic carbon allocation and phenology.

  17. South Asian Climate Response to Local and Remote Aerosol Emissions Perturbations

    NASA Astrophysics Data System (ADS)

    Shawki, Dilshad; Voulgarakis, Apostolos; Kasoar, Matthew; Chakraborty, Arindam; Srinivasan, Jayaraman

    2016-04-01

    The South Asian population's livelihood largely depends on the rainfall brought on by the summer monsoon. Some of the highest emissions of short-lived anthropogenic aerosols can also be found in this region. Understanding how the long-term mean state of the south Asian climate will change in response to both local and remote aerosol emissions is of great importance, since the South Asian monsoon forms a key part of the global climate system. Recent studies suggest that South Asian temperature and precipitation responses to aerosol changes are different depending on the location and type of aerosol. Here, we use the UK Met Office HadGEM3 coupled climate model to investigate the South Asian climate response to removing sulphur dioxide emissions (producing sulphate aerosols) locally and remotely through centennial scale equilibrium simulations. The summer precipitation response to remote emissions (e.g. from Europe, United States, East Asia) and to local emissions (e.g. south Asia) is of opposite sign over land, but of the same sign and pattern over the Indian Ocean. Over land, reductions in rainfall are seen when removing sulphur dioxide from south Asia, while there is an increase in rainfall due to emissions from remote mid-latitudes regions. Remotely emitted aerosols have a greater ability to change the large-scale temperature and circulation patterns compared to locally emitted aerosols. They cause a northward shift of the intertropical convergence zone towards the northern hemisphere and increase the land-sea thermal contrast, which strengthens the monsoon circulation. Local emissions cause a change in composition over the area of interest, which modulates the precipitation response over land and counters the strengthened circulation through local dynamical and land surface changes in the pre-monsoon season. More work is warranted to allow for comparisons with other models, as well as to further our understanding of the processes involved using a similarly

  18. Emission controls versus meteorological conditions in determining aerosol concentrations in Beijing during the 2008 Olympic Games

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Liu, X.; Zhao, C.; Zhang, M.; Wang, Y.

    2011-06-01

    A series of emission control measures were undertaken in Beijing and the adjacent provinces in China during the 2008 Beijing Olympic Games on 8-24 August 2008. This provides a unique opportunity for investigating the effectiveness of emission controls on air pollution in Beijing. We conducted a series of numerical experiments over East Asia for the period of July to September 2008 using a coupled meteorology-chemistry model (WRF-Chem). Model can generally reproduce the observed variation of aerosol concentrations. Consistent with observations, modeled concentrations of aerosol species (sulfate, nitrate, ammonium, black carbon, organic carbon, total particulate matter) in Beijing were decreased by 30-50 % during the Olympic period compared to the other periods in July and August in 2008 and the same period in 2007. Model results indicate that emission controls were effective in reducing the aerosol concentrations by comparing simulations with and without emission controls. However, our analysis suggests that meteorological conditions (e.g., wind direction and precipitation) are at least as important as emission controls in producing the low aerosol concentrations appearing during the Olympic period. Transport from the regions surrounding Beijing determines the temporal variation of aerosol concentrations in Beijing. Based on the budget analysis, we suggest that to improve the air quality over Beijing, emission control strategy should focus on the regional scale instead of the local scale.

  19. Emission controls versus meteorological conditions in determining aerosol concentrations in Beijing during the 2008 Olympic Games

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Liu, X.; Zhao, C.; Zhang, M.

    2011-12-01

    A series of emission control measures were undertaken in Beijing and the adjacent provinces in China during the 2008 Beijing Olympic Games on 8-24 August 2008. This provides a unique opportunity for investigating the effectiveness of emission controls on air pollution in Beijing. We conducted a series of numerical experiments over East Asia for the period of July to September 2008 using a coupled meteorology-chemistry model (WRF-Chem). Model can generally reproduce the observed variation of aerosol concentrations. Consistent with observations, modeled concentrations of aerosol species (sulfate, nitrate, ammonium, black carbon, organic carbon, total particulate matter) in Beijing were decreased by 30-50% during the Olympic period compared to the other periods in July and August in 2008 and the same period in 2007. Model results indicate that emission controls were effective in reducing the aerosol concentrations by comparing simulations with and without emission controls. In addition to emission controls, our analysis suggests that meteorological conditions (e.g. wind direction and precipitation) were also important in producing the low aerosol concentrations appearing during the Olympic period. Transport from the regions surrounding Beijing determined the daily variation of aerosol concentrations in Beijing. Based on the budget analysis, we suggest that to improve the air quality over Beijing, emission control strategy should focus on the regional scale instead of the local scale.

  20. Emission Controls Versus Meteorological Conditions in Determining Aerosol Concentrations in Beijing during the 2008 Olympic Games

    SciTech Connect

    Gao, Yi; Liu, Xiaohong; Zhao, Chun; Zhang, Meigen

    2011-12-12

    A series of emission control measures were undertaken in Beijing and the adjacent provinces in China during the 2008 Beijing Olympic Games on August 8th-24th, 2008. This provides a unique opportunity for investigating the effectiveness of emission controls on air pollution in Beijing. We conducted a series of numerical experiments over East Asia for the period of July to September 2008 using a coupled meteorology-chemistry model (WRF-Chem). Model can generally reproduce the observed variation of aerosol concentrations. Consistent with observations, modeled concentrations of aerosol species (sulfate, nitrate, ammonium, black carbon, organic carbon, total particulate matter) in Beijing were decreased by 30-50% during the Olympic period compared to the other periods in July and August in 2008 and the same period in 2007. Model results indicate that emission controls were effective in reducing the aerosol concentrations by comparing simulations with and without emission controls. However, our analysis suggests that meteorological conditions (e.g., wind direction and precipitation) are at least as important as emission controls in producing the low aerosol concentrations appearing during the Olympic period. Transport from the regions surrounding Beijing determines the temporal variation of aerosol concentrations in Beijing. Based on the budget analysis, we suggest that emission control strategy should focus on the regional scale instead of the local scale to improve the air quality over Beijing.

  1. Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

    NASA Astrophysics Data System (ADS)

    Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

    2014-06-01

    Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photooxidation under a range of controlled conditions (RH ∼65-89%, VOC/NOx ∼3-9 and NOx ∼2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line, chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene, but low isoprene emitter, and its emissions were observed to produce measureable amounts of SOA via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e., in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photooxidation products of the minor VOCs co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally-isoprene emitting landscapes in Southeast Asia. Moreover, in general the amount of aerosol mass produced from the emissions of the principally

  2. Simulating ozone concentrations using precursor emission inventories in Delhi - National Capital Region of India

    NASA Astrophysics Data System (ADS)

    Sharma, Sumit; Khare, Mukesh

    2017-02-01

    This study simulates ground level ozone concentrations in a heavily populated and polluted National Capital Region (NCR- Delhi) in India. Multi-sectoral emission inventories of ozone precursors are prepared at a high resolution of 4 × 4 km2 for the whole region covering the capital city of Delhi along with other surrounding towns and rural regions in NCR. Emission inventories show that transport sector accounts for 55% of the total NOx emissions, followed by power plants (23%) and diesel generator sets (7%). In NMVOC inventories, transport sector again accounts for 33%, followed by evaporative emissions released from solvent use and fuel handling activities (30%), and agricultural residue burning (28%). Refuse burning contributes to 73% of CO emissions mainly due to incomplete combustion, followed by agricultural residue burning (14%). These emissions are spatially and temporally distributed across the study domain and are fed into the WRF-CMAQ models to predict ozone concentrations for the year 2012. Model validations are carried out with the observed values at different monitoring stations in Delhi. The performance of the models over various metrics used for evaluation was found to be satisfactory. Summers and post-monsoon seasons were better simulated than monsoon and winter seasons. Simulations have shown higher concentrations of ozone formation during summers and lesser during winters and monsoon seasons, mainly due to varying solar radiation affecting photo-chemical activities. Ozone concentrations are observed lower at those locations where NOx emissions are higher, and concentrations increase close to the boundary of study domain when compared to the center of Delhi city. Downwind regions to Delhi are influenced by the ozone formed due to plume of precursor emissions released from Delhi. Considering significant background contributions, regional scale controls are required for reducing ozone in NCR.

  3. Aerosol synthesis of nano and micro-scale zero valent metal particles from oxide precursors

    SciTech Connect

    Phillips, Jonathan; Luhrs, Claudia; Lesman, Zayd; Soliman, Haytham; Zea, Hugo

    2010-01-01

    In this work a novel aerosol method, derived form the batch Reduction/Expansion Synthesis (RES) method, for production of nano / micro-scale metal particles from oxides and hydroxides is presented. In the Aerosol-RES (A-RES) method, an aerosol, consisting of a physical mixture of urea and metal oxide or hydroxides, is passed through a heated oven (1000 C) with a residence time of the order of 1 second, producing pure (zero valent) metal particles. It appears that the process is flexible regarding metal or alloy identity, allows control of particle size and can be readily scaled to very large throughput. Current work is focused on creating nanoparticles of metal and metal alloy using this method. Although this is primarily a report on observations, some key elements of the chemistry are clear. In particular, the reducing species produced by urea decomposition are the primary agents responsible for reduction of oxides and hydroxides to metal. It is also likely that the rapid expansion that takes place when solid/liquid urea decomposes to form gas species influences the final morphology of the particles.

  4. Implications of the Temporal Resolution of Fire Emissions on Direct and Indirect Aerosol Effects

    NASA Astrophysics Data System (ADS)

    Darmenov, A.; Barahona, D.; Kim, K. M.; da Silva, A.; Colarco, P. R.; Govindaraju, R.

    2014-12-01

    Biomass burning is an important source of particulates and trace gases and a major element of the terrestrial carbon cycle. Well constrained emissions from open vegetation fires in both time and space are needed to model direct and indirect effect of biomass burning aerosols, homogeneous and heterogeneous chemistry in the atmosphere and perform credible integrated earth system analysis, climate and air pollution studies. However representing fires in regional and global numerical models is challenging because of the subgrid scales at which fire processes operate. An example of apparent discrepancy in scales is the use of monthly- or seasonal-mean fire emissions which given the stochastic nature of fires means that at certain spatial scales the temporal behavior of emissions becomes influenced by individual fire events and becomes more variable. The present study aims at investigating the impact of monthly-mean fire emissions on direct and indirect aerosol effects. Key element of our work is the use of fire radiative power (FRP) based emissions and a global fully interactive cloud-aerosol-radiation modeling system. We used the Goddard Earth Observing System Model, Version 5 (GEOS-5) with two moment cloud microphysics and explicit cloud droplet activation and ice nucleation. GEOS-5 is coupled with an online version of the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. Biomass burning emissions used in this study are from the Quick Fire Emission Dataset (QFED) available daily at up to 0.1 degrees horizontal resolution. We performed experiments with daily-mean and monthly-mean QFED emissions at two degree horizontal resolutions and report differences in aerosol burden and radiative forcing, for example we found that regional differences of clear-sky aerosol direct radiative effect at the surface and at the top of the atmosphere in MAM and JJA can be as high as 4 Wm-2 and 3 Wm-2, respectively.

  5. Ground and Airborne Aerosol Composition Measurements of California Coastal Chaparral Smoke Emissions

    NASA Astrophysics Data System (ADS)

    Craven, J. S.; Sorooshian, A.; Hersey, S. P.; Metcalf, A. R.; Schilling-Fahnestock, K.; Newman, S.; Akagi, S. K.; Taylor, J.; McMeeking, G.; Coe, H.; Tang, P.; Cocker, D. R., III; Yokelson, R. J.; Flagan, R. C.; Seinfeld, J.

    2014-12-01

    Wildfire smoke has large local to global pollution impacts. We present aerosol composition data from two fires in southern California. We measured organic aerosol (OA) of nascent and aged (4 h) smoke from the Williams Fire during the 2009 airborne San Luis Obispo Biomass Burning Campaign (SLOBB). The net ΔOA/ΔCO2 decreased by ~20%; however, positive matrix factorization (PMF) analysis of the organic mass spectra supports two factors that enable the OA emissions to be separated into fresh and oxidized OA. The Δfresh BBOA/ΔCO2 had a steeper decline than the ΔOA/ΔCO2 consistent with outgassing of semi-voltile organic compounds (SVOCs) due to dilution, whereas the Δoxidized BBOA/ΔCO2 increased from its initial value, consist with formation of secondary organic aerosol (SOA). We compare these fresh and oxidized mass spectral signatures, along with chaparral smoke samples measured in the Missoula Fire Lab, to ground-based aerosol measurements made during the Station Fire that occurred one month earlier than the Williams Fire during the Pasadena Aerosol Characterization Observatory Campaign (PACO). Night and daytime aerosol smoke emissions were sampled for one week during the Station Fire. Daytime organic aerosol smoke emissions exhibited larger variability both in mass concentration and composition than nighttime smoke emissions. Both levoglucosan and potassium, known biomass burning tracers, were measured and had distinct time series, supporting diversity in the flaming vs. smoldering initial burning conditions. Similar to the Williams Fire, PMF of the Station Fire mass spectra also reveal two biomass burning factors, one that is less oxidized and correlates strongly with levoglucosan measurements and one that is heavily oxidized and correlates in time with the potassium signal. These two campaigns have allowed us to probe fresh and oxidized smoke in both night and daytime conditions, and PMF results have revealed that at least two emission factors are useful to

  6. The influence of ozone precursor emissions from four world regions on tropospheric composition and radiative climate forcing

    NASA Astrophysics Data System (ADS)

    Fry, Meridith M.; Naik, Vaishali; West, J. Jason; Schwarzkopf, M. Daniel; Fiore, Arlene M.; Collins, William J.; Dentener, Frank J.; Shindell, Drew T.; Atherton, Cyndi; Bergmann, Daniel; Duncan, Bryan N.; Hess, Peter; MacKenzie, Ian A.; Marmer, Elina; Schultz, Martin G.; Szopa, Sophie; Wild, Oliver; Zeng, Guang

    2012-04-01

    Ozone (O3) precursor emissions influence regional and global climate and air quality through changes in tropospheric O3 and oxidants, which also influence methane (CH4) and sulfate aerosols (SO42-). We examine changes in the tropospheric composition of O3, CH4, SO42- and global net radiative forcing (RF) for 20% reductions in global CH4 burden and in anthropogenic O3 precursor emissions (NOx, NMVOC, and CO) from four regions (East Asia, Europe and Northern Africa, North America, and South Asia) using the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) simulations, assessing uncertainty (mean ± 1 standard deviation) across multiple CTMs. We evaluate steady state O3responses, including long-term feedbacks via CH4. With a radiative transfer model that includes greenhouse gases and the aerosol direct effect, we find that regional NOx reductions produce global, annually averaged positive net RFs (0.2 ± 0.6 to 1.7 ± 2 mWm-2/Tg N yr-1), with some variation among models. Negative net RFs result from reductions in global CH4 (-162.6 ± 2 mWm-2 for a change from 1760 to 1408 ppbv CH4) and regional NMVOC (-0.4 ± 0.2 to -0.7 ± 0.2 mWm-2/Tg C yr-1) and CO emissions (-0.13 ± 0.02 to -0.15 ± 0.02 mWm-2/Tg CO yr-1). Including the effect of O3 on CO2 uptake by vegetation likely makes these net RFs more negative by -1.9 to -5.2 mWm-2/Tg N yr-1, -0.2 to -0.7 mWm-2/Tg C yr-1, and -0.02 to -0.05 mWm-2/Tg CO yr-1. Net RF impacts reflect the distribution of concentration changes, where RF is affected locally by changes in SO42-, regionally to hemispherically by O3, and globally by CH4. Global annual average SO42- responses to oxidant changes range from 0.4 ± 2.6 to -1.9 ± 1.3 Gg for NOxreductions, 0.1 ± 1.2 to -0.9 ± 0.8 Gg for NMVOC reductions, and -0.09 ± 0.5 to -0.9 ± 0.8 Gg for CO reductions, suggesting additional research is needed. The 100-year global warming potentials (GWP100) are calculated for the global CH

  7. The ISA-MIP Historical Eruption SO2 Emissions Assessment (HErSEA): an intercomparison for interactive stratospheric aerosol models

    NASA Astrophysics Data System (ADS)

    Mann, Graham; Dhomse, Sandip; Sheng, Jianxiong; Mills, Mike

    2016-04-01

    Major historical volcanic eruptions have injected huge amounts of sulphur dioxide into the stratosphere with observations showing an enhancement of the stratospheric aerosol layer for several years (ASAP, 2006). Such long-lasting increases in stratospheric aerosol loading cool the Earth's surface by scattering incoming solar radiation and warm the stratosphere via absorption of near infra-red solar and long-wave terrestrial radiation with complex effects on climate (e.g. Robock, 2000). Two recent modelling studies of Mount Pinatubo (Dhomse et al., 2014; Sheng et al. 2015) have highlighted that observations suggest the sulphur loading of the volcanically enhanced stratospheric aerosol may have been considerably lower than suggested by measurements of the injected SO2. This poster describes a new model intercomparison activity "ISA-MIP" for interactive stratospheric aerosol models within the framework of the SPARC initiative on Stratospheric Sulphur and its Role in Climate (SSiRC). The new "Historical Eruption SO2 emissions Assessment" (HErSEA) will intercompare model simulations of the three largest volcanic perturbations to the stratosphere in the last 50 years, 1963 Mt Agung, 1982 El Chichon and 1991 Mt Pinatubo. The aim is to assess how effectively the emitted SO2 translates into perturbations to stratospheric aerosol properties and simulated radiative forcings in different composition-climate models with interactive stratospheric aerosol (ISA). Each modelling group will run a mini-ensemble of transient AMIP-type runs for the 3 eruptions with a control no-eruption run followed by upper and lower bound injection amount estimates and 3 different injection height settings for two shallow (e.g. 19-21km amd 23-25km) and one deep (e.g. 19-25km) injection. First order analysis will intercompare stratospheric aerosol metrics such as 2D-monthly AOD(550nm, 1020nm) and timeseries of tropical and NH/SH mid-visible extinction at three different models levels (15, 20 and 25km

  8. CuInS2 Films Deposited by Aerosol-Assisted Chemical Vapor Deposition Using Ternary Single-Source Precursors

    NASA Technical Reports Server (NTRS)

    Jin, Michael; Banger, Kal; Harris, Jerry; Hepp, Aloysius

    2003-01-01

    Polycrystalline CuInS2 films were deposited by aerosol-assisted chemical vapor deposition using both solid and liquid ternary single-source precursors (SSPs) which were prepared in-house. Films with either (112) or (204/220) preferred orientation, had a chalcopyrite structure, and (112)-oriented films contained more copper than (204/220)-oriented films. The preferred orientation of the film is likely related to the decomposition and reaction kinetics associated with the molecular structure of the precursors at the substrate. Interestingly, the (204/220)-oriented films were always In-rich and were accompanied by a secondary phase. From the results of post-growth annealing, etching experiments, and Raman spectroscopic data, the secondary phase was identified as an In-rich compound. On the contrary, (112)-oriented films were always obtained with a minimal amount of the secondary phase, and had a maximum grain size of about 0.5 micron. Electrical and optical properties of all the films grown were characterized. They all showed p-type conduction with an electrical resistivity between 0.1 and 30 Omega-cm, and an optical band gap of approximately 1.46 eV +/- 0.02, as deposited. The material properties of deposited films revealed this methodology of using SSPs for fabricating chalcopyrite-based solar cells to be highly promising.

  9. CuInS2 Films Deposited by Aerosol-Assisted Chemical Vapor Deposition Using Ternary Single-Source Precursors

    NASA Technical Reports Server (NTRS)

    Jin, Michael H.-C.; Banger, Kulbinder K.; Harris, Jerry D.; Hepp, Aloysius F.

    2004-01-01

    Polycrystalline CuInS2 films were deposited by aerosol-assisted chemical vapor deposition using both solid and liquid ternary single-source precursors (SSPs) prepared in-house. Films with either (112) or (204/220) preferred orientation were obtained, and compositional analysis showed that (112)-oriented films contained more copper than (204/220)-oriented films. Using X-ray diffraction, the signature of chalcopyrite structure was often confirmed for (112)-oriented films. The preferred orientation of the film is likely related to the decomposition and reaction kinetics associated with the molecular structure of the precursors at the substrate. Interestingly, the (204/220)-oriented films were always accompanied by a secondary phase, which was identified as an unknown In-rich compound from the results of post-growth annealing, etching experiments, and Raman spectroscopic data. By increasing Cu to In ratio in the film, (112)-oriented films were obtained with a maximum grain size of about 0.5 micrometers, and their X-ray diffractions did not show any observable signature of the In secondary phase. Electrical and optical properties of all the films grown were characterized. They all showed p-type conduction with an electrical resistivity between 0.1 omega cm and 30 omega cm, and an optical band gap of 1.46eV +/- 0.02, as deposited. The material properties of deposited films revealed this methodology of using SSPs for fabricating chalcopyrite-based solar cells to be highly promising.

  10. Infrared limb emission measurements of aerosol in the troposphere and stratosphere

    NASA Astrophysics Data System (ADS)

    Griessbach, Sabine; Hoffmann, Lars; Spang, Reinhold; von Hobe, Marc; Müller, Rolf; Riese, Martin

    2016-09-01

    Altitude-resolved aerosol detection in the upper troposphere and lower stratosphere (UTLS) is a challenging task for remote sensing instruments. Infrared limb emission measurements provide vertically resolved global measurements at day- and nighttime in the UTLS. For high-spectral-resolution infrared limb instruments we present here a new method to detect aerosol and separate between ice and non-ice particles. The method is based on an improved aerosol-cloud index that identifies infrared limb emission spectra affected by non-ice aerosol or ice clouds. For the discrimination between non-ice aerosol and ice clouds we employed brightness temperature difference correlations. The discrimination thresholds for this method were derived from radiative transfer simulations (including scattering) and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)/Envisat measurements obtained in 2011. We demonstrate the value of this approach for observations of volcanic ash and sulfate aerosol originating from the Grímsvötn (Iceland, 64° N), Puyehue-Cordón Caulle (Chile, 40° S), and Nabro (Eritrea, 13° N) eruptions in May and June 2011 by comparing the MIPAS volcanic aerosol detections with Atmospheric Infrared Sounder (AIRS) volcanic ash and SO2 measurements.

  11. Primary gas- and particle-phase emissions and secondary organic aerosol production from gasoline and diesel off-road engines.

    PubMed

    Gordon, Timothy D; Tkacik, Daniel S; Presto, Albert A; Zhang, Mang; Jathar, Shantanu H; Nguyen, Ngoc T; Massetti, John; Truong, Tin; Cicero-Fernandez, Pablo; Maddox, Christine; Rieger, Paul; Chattopadhyay, Sulekha; Maldonado, Hector; Maricq, M Matti; Robinson, Allen L

    2013-12-17

    Dilution and smog chamber experiments were performed to characterize the primary emissions and secondary organic aerosol (SOA) formation from gasoline and diesel small off-road engines (SOREs). These engines are high emitters of primary gas- and particle-phase pollutants relative to their fuel consumption. Two- and 4-stroke gasoline SOREs emit much more (up to 3 orders of magnitude more) nonmethane organic gases (NMOGs), primary PM and organic carbon than newer on-road gasoline vehicles (per kg of fuel burned). The primary emissions from a diesel transportation refrigeration unit were similar to those of older, uncontrolled diesel engines used in on-road vehicles (e.g., premodel year 2007 heavy-duty diesel trucks). Two-strokes emitted the largest fractional (and absolute) amount of SOA precursors compared to diesel and 4-stroke gasoline SOREs; however, 35-80% of the NMOG emissions from the engines could not be speciated using traditional gas chromatography or high-performance liquid chromatography. After 3 h of photo-oxidation in a smog chamber, dilute emissions from both 2- and 4-stroke gasoline SOREs produced large amounts of semivolatile SOA. The effective SOA yield (defined as the ratio of SOA mass to estimated mass of reacted precursors) was 2-4% for 2- and 4-stroke SOREs, which is comparable to yields from dilute exhaust from older passenger cars and unburned gasoline. This suggests that much of the SOA production was due to unburned fuel and/or lubrication oil. The total PM contribution of different mobile source categories to the ambient PM burden was calculated by combining primary emission, SOA production and fuel consumption data. Relative to their fuel consumption, SOREs are disproportionately high total PM sources; however, the vastly greater fuel consumption of on-road vehicles renders them (on-road vehicles) the dominant mobile source of ambient PM in the Los Angeles area.

  12. Cross influences of ozone and sulfate precursor emissions changes on air quality and climate.

    PubMed

    Unger, Nadine; Shindell, Drew T; Koch, Dorothy M; Streets, David G

    2006-03-21

    Tropospheric O(3) and sulfate both contribute to air pollution and climate forcing. There is a growing realization that air quality and climate change issues are strongly connected. To date, the importance of the coupling between O(3) and sulfate has not been fully appreciated, and thus regulations treat each pollutant separately. We show that emissions of O(3) precursors can dramatically affect regional sulfate air quality and climate forcing. At 2030 in an A1B future, increased O(3) precursor emissions enhance surface sulfate over India and China by up to 20% because of increased levels of OH and gas-phase SO(2) oxidation rates and add up to 20% to the direct sulfate forcing for that region relative to the present day. Hence, O(3) precursors impose an indirect forcing via sulfate, which is more than twice the direct O(3) forcing itself (compare -0.61 vs. +0.35 W/m(2)). Regulatory policy should consider both air quality and climate and should address O(3) and sulfate simultaneously because of the strong interaction between these species.

  13. Declining ozone exposure of European vegetation under climate change and reduced precursor emissions

    NASA Astrophysics Data System (ADS)

    Klingberg, J.; Engardt, M.; Karlsson, P. E.; Langner, J.; Pleijel, H.

    2014-10-01

    The impacts of changes in ozone precursor emissions as well as climate change on the future ozone exposure of the vegetation in Europe were investigated. The ozone exposure is expressed as AOT40 (Accumulated exposure Over a Threshold of 40 ppb O3) as well as PODY (Phytotoxic Ozone Dose above a threshold Y). A new method is suggested to express how the length of the period during the year when coniferous and evergreen trees are sensitive to ozone might be affected by climate change. Ozone precursor emission changes from the RCP4.5 scenario were combined with climate simulations based on the IPCC SRES A1B scenario and used as input to the Eulerian Chemistry Transport Model MATCH from which projections of ozone concentrations were derived. The ozone exposure of vegetation over Europe expressed as AOT40 was projected to be substantially reduced between the periods 1990-2009 and 2040-2059 to levels which are well below critical levels used for vegetation in the EU directive 2008/50/EC as well as for crops and forests used in the LRTAP convention, despite that the future climate resulted in prolonged yearly ozone sensitive periods. The reduction in AOT40 was mainly driven by the emission reductions, not changes in the climate. For the toxicologically more relevant POD1 index the projected reductions were smaller, but still significant. The values for POD1 for the time period 2040-2059 were not projected to decrease to levels which are below critical levels for forest trees, represented by Norway spruce. This study shows that substantial reductions of ozone precursor emissions have the potential to strongly reduce the future risk for ozone effects on the European vegetation, even if concurrent climate change promotes ozone formation.

  14. Mechanistic understanding of aerosol emissions from a brazing operation.

    PubMed

    Zimmer, A T; Biswas, P

    2000-01-01

    Welding operations produce gaseous and aerosol by-products that can have adverse health effects. A laboratory furnace study was conducted to aid understanding of the chemical and aerosol behavior of a widely used, self-fluxing brazing alloy (89% Cu, 6% Ag, 5% P) that is also used with a supplemental fluxing compound to prevent oxidation at the molten metal surface. The results indicate that the aerosols generated by the alloy are transient (produced over a short duration of time) and are associated with mass transfer of phosphorus species from the molten metal surface to the surrounding gas. In contrast, when the alloy was used in conjunction with the supplemental fluxing compound, a relatively nontransient, submicron-size aerosol was generated that was several orders of magnitude higher in concentration. Thermodynamic equilibrium analysis suggests that fluoride (a major constituent in the fluxing compound) played a significant role in reacting with the brazing alloy metals to form gas phase metal fluoride compounds that had high vapor pressures when compared with their elemental or oxide forms. As these metal-fluoride vapors cooled, submicron-size particles were formed mainly through nucleation and condensation growth processes. In addition, the equilibrium results revealed the potential formation of severe pulmonary irritants (HF and BF3) from heating the supplemental fluxing compound. These results demonstrated the importance of fluxing compounds in the formation of brazing fumes, and suggest that fluxing compounds could be selected that serve their metallurgical intention and suppress the formation of aerosols.

  15. Methods of analysis for complex organic aerosol mixtures from urban emission sources of particulate carbon

    SciTech Connect

    Mazurek, M.A. ); Hildemann, L.M. . Dept. of Civil Engineering); Cass, G.R.; Rogge, W.F. . Dept. of Environmental Engineering Science); Simoneit, B.R.T. . Coll. of Oceanography)

    1990-04-01

    Extractable organic compounds having between 6 to 40 carbon atoms comprise an important mass fraction of the fine particulate matter samples from major urban emission sources. Depending on the emission source type, this solvent-soluble fraction accounts for <20% to 100% of the total organic aerosol mass, as measured by quantitative high-resolution has chromatography (HRGC) with flame ionization detection. In addition to total extract quantitation, HRGC can be applied to further analyses of the mass distributions of elutable organics present in the complex aerosol extract mixtures, thus generating profiles that serve as fingerprints'' for the sources of interest. This HRGC analytical method is applied to emission source samples that contain between 7 to 12,000 {mu}g/filter organic carbon. It is shown to be a sensitive technique for analysis of carbonaceous aerosol extract mixtures having diverse mass loadings and species distributions. This study describes the analytical chemical methods that have been applied to: the construction of chemical mass balances based on the mass of fine organic aerosol emitted for major urban sources of particulate carbon; and the generation of discrete emission source chemical profiles derived from chromatographic characteristics of the organic aerosol components. 21 refs., 1 fig., 2 tabs.

  16. Kudzu (Pueraria montana) Invasion Doubles Emissions of Nitric Oxide, a Precursor to Tropospheric Ozone.

    NASA Astrophysics Data System (ADS)

    Hickman, J. E.; Wu, S.; Mickley, L. J.; Lerdau, M. T.

    2008-12-01

    Nitrogen-fixing plants can increase rates of nitrogen (N) cycling in soils, fluxes of the greenhouse gas nitrous oxide (N2O), and fluxes of the ozone precursor nitric oxide (NO). Invasion by the nitrogen-fixing legume kudzu (Pueraria montana) across millions of hectares in the southeastern United States could be contributing to increased ozone concentrations. Ozone formation in the Southeast is broadly limited by atmospheric NO concentrations, so perturbations to the N cycle by kudzu have the potential to increase ozone concentrations in the region. At three sites in Madison County, Georgia, kudzu invasion increased rates of net N mineralization by up to an order of magnitude and rates of net nitrification and soil pools of NO3- and NO2- by up to 500%. Emissions of NO from soils invaded by kudzu averaged 2.81 ng NO-N cm-2 h-1, significantly higher than emissions from soil dominated by native vegetation, which averaged 1.24 ng NO-N cm-2 h-1. Emissions of N2O display a trend towards increasing under kudzu invasion, but N2O emissions at these sites were three orders of magnitude smaller than emissions of NO. Atmospheric chemical modeling suggests that these higher NO emissions could increase ozone concentrations in the region by up to 2 ppb. We propose that kudzu invasion in the southeastern United States represents a novel threat to air quality and could increase the frequency with which federal ozone standards are exceeded.

  17. Aerosols

    Atmospheric Science Data Center

    2013-04-17

    ... article title:  Aerosols over Central and Eastern Europe     View Larger Image ... last weeks of March 2003, widespread aerosol pollution over Europe was detected by several satellite-borne instruments. The Multi-angle ...

  18. Webinar Presentation: Linking Regional Aerosol Emission Changes with Multiple Impact Measures through Direct and Cloud-Related Forcing Estimates

    EPA Pesticide Factsheets

    This presentation, Linking Regional Aerosol Emission Changes with Multiple Impact Measures through Direct and Cloud-Related Forcing Estimates, was given at the STAR Black Carbon 2016 Webinar Series: Accounting for Impact, Emissions, and Uncertainty.

  19. MODELING THE EFFECT OF CHLORINE EMISSIONS ON ATMOSPHERIC OZONE AND SECONDARY ORGANIC AEROSOL CONCENTRATIONS ACROSS THE UNITED STATES

    EPA Science Inventory

    This paper presents the modeled effects of natural and anthropogenic chlorine emissions on the atmospheric concentrations of ozone and secondary organic aerosol across the United States. The model calculations include anthropogenic molecular chlorine emissions, anthropogenic hypo...

  20. Interannual variability of tropospheric trace gases and aerosols: The role of biomass burning emissions

    NASA Astrophysics Data System (ADS)

    Voulgarakis, Apostolos; Marlier, Miriam E.; Faluvegi, Greg; Shindell, Drew T.; Tsigaridis, Kostas; Mangeon, Stéphane

    2015-07-01

    Fires are responsible for a range of gaseous and aerosol emissions. However, their influence on the interannual variability of atmospheric trace gases and aerosols has not been systematically investigated from a global perspective. We examine biomass burning emissions as a driver of interannual variability of large-scale abundances of short-lived constituents such as carbon monoxide (CO), hydroxyl radicals (OH), ozone, and aerosols using the Goddard Institute for Space Studies ModelE composition-climate model and a range of observations, with an emphasis on satellite information. Our model captures the observed variability of the constituents examined in most cases, but with substantial underestimates in boreal regions. The strongest interannual variability on a global scale is found for carbon monoxide (~10% for its global annual burden), while the lowest is found for tropospheric ozone (~1% for its global annual burden). Regionally, aerosol optical depth shows the largest variability which exceeds 50%. Areas of strong variability of both aerosols and CO include the tropical land regions (especially Equatorial Asia and South America) and northern high latitudes, while even regions in the northern midlatitudes experience substantial interannual variability of aerosols. Ozone variability peaks over equatorial Asia in boreal autumn, partly due to varying biomass burning emissions, and over the western and central Pacific in the rest of the year, mainly due to meteorological fluctuations. We find that biomass burning emissions are almost entirely responsible for global CO interannual variability, and similarly important for OH variability. The same is true for global and regional aerosol variability, especially when not taking into account dust and sea-salt particles. We show that important implications can arise from such interannual influences for regional climate and air quality.

  1. Simulating secondary organic aerosol from missing diesel-related intermediate-volatility organic compound emissions during the Clean Air for London (ClearfLo) campaign

    NASA Astrophysics Data System (ADS)

    Ots, Riinu; Young, Dominique E.; Vieno, Massimo; Xu, Lu; Dunmore, Rachel E.; Allan, James D.; Coe, Hugh; Williams, Leah R.; Herndon, Scott C.; Ng, Nga L.; Hamilton, Jacqueline F.; Bergström, Robert; Di Marco, Chiara; Nemitz, Eiko; Mackenzie, Ian A.; Kuenen, Jeroen J. P.; Green, David C.; Reis, Stefan; Heal, Mathew R.

    2016-05-01

    We present high-resolution (5 km × 5 km) atmospheric chemical transport model (ACTM) simulations of the impact of newly estimated traffic-related emissions on secondary organic aerosol (SOA) formation over the UK for 2012. Our simulations include additional diesel-related intermediate-volatility organic compound (IVOC) emissions derived directly from comprehensive field measurements at an urban background site in London during the 2012 Clean Air for London (ClearfLo) campaign. Our IVOC emissions are added proportionally to VOC emissions, as opposed to proportionally to primary organic aerosol (POA) as has been done by previous ACTM studies seeking to simulate the effects of these missing emissions. Modelled concentrations are evaluated against hourly and daily measurements of organic aerosol (OA) components derived from aerosol mass spectrometer (AMS) measurements also made during the ClearfLo campaign at three sites in the London area. According to the model simulations, diesel-related IVOCs can explain on average ˜ 30 % of the annual SOA in and around London. Furthermore, the 90th percentile of modelled daily SOA concentrations for the whole year is 3.8 µg m-3, constituting a notable addition to total particulate matter. More measurements of these precursors (currently not included in official emissions inventories) is recommended. During the period of concurrent measurements, SOA concentrations at the Detling rural background location east of London were greater than at the central London location. The model shows that this was caused by an intense pollution plume with a strong gradient of imported SOA passing over the rural location. This demonstrates the value of modelling for supporting the interpretation of measurements taken at different sites or for short durations.

  2. Characterizing the impact of urban emissions on regional aerosol particles: airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouche, N.; Pichon, J.-M.; Bourianne, T.; Gomes, L.; Prevot, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2014-02-01

    The MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris, using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS), giving detailed information on the non-refractory submicron aerosol species. The mass concentration of black carbon (BC), measured by a particle absorption soot photometer (PSAP), was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA), BC, and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (-log(NOx / NOy)). Plotting the equivalent ratios of different organic aerosol species (LV-OOA, SV-OOA, and HOA) illustrate that the increase in OA is a result of secondary organic aerosol (SOA) formation. Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in London, Mexico City, and in New England, USA. Using the measured SOA volatile organic compounds (VOCs) species together with organic aerosol formation

  3. Biomass burning emissions over northern Australia constrained by aerosol measurements: I—Modelling the distribution of hourly emissions

    NASA Astrophysics Data System (ADS)

    Meyer, C. P. (Mick); Luhar, Ashok K.; Mitchell, Ross M.

    Emissions of aerosol from biomass burning in northern Australia are globally significant, yet existing estimates of their magnitude are essentially unconstrained by observation. This two-part series (see Part II by Luhar et al. [2008. Biomass burning emissions over northern Australia constrained by aerosol measurements: II—Model validation, and impacts on air quality and radiative forcing. Atmospheric Environment, submitted for publication] seeks to address this by first formulating a scheme to determine the emissions from the Top End region of the Northern Territory during the 2004 burning season at a high temporal and spatial resolution (1 h, 1 km). The emissions are then validated using a meteorological and transport model called TAPM coupled with a variety of field measurements. The high resolution not only enables validation against various meteorological and aerosol data sets, but also allows prediction of local air quality events. Essential inputs to the emission calculations are satellite-based measurements of fire scars, yielding burnt areas, and hotspots, providing timing information on daily basis. It is shown that hotspots without associated fire scars must be taken into account in order to produce credible aerosol fields. Prediction of emissions at hourly time resolution is enabled by assigning a diurnal variation based on a McArthur fire danger meter. The total carbon emission for the 2004 season is computed to be 67.6 Tg, in remarkable agreement with the bulk estimate of 64.3 Tg derived for the Australian National Greenhouse Gas Inventory, and comparable to the figure of 57.0 Tg determined from the Global Fire Emissions Database (GFEDv2). The total PM 2.5 (particulate matter with an aerodynamic diameter of 2.5 μm or less) emission is computed to be 0.67 Tg. The transport modelling shows that emissions leaving the study region are largely advected to the west over the Timor Sea towards the Indonesian archipelago from April to September, shifting to

  4. Impact on aerosol emissions in China and India on local and global climate

    NASA Astrophysics Data System (ADS)

    Kühn, Thomas; Partanen, Antti-Ilari; Henriksson, Svante V.; Bergman, Tommi; Laakso, Anton; Kokkola, Harri; Romakkaniemi, Sami; Laaksonen, Ari

    2013-04-01

    Existing surface temperature records show warming in the beginning of last century, followed by cooling starting from 1940 and again strong heating from 1975 until recent years. This behaviour has been attributed to increase in the greenhouse gas and aerosol emission as well as to natural variability of climate. Making a difference between these is crucial as climate predictions and international policy related to emission reductions are based on the models that are mainly evaluated against the historical temperature records. While in Europe and North America the aerosol emissions have decreased since the late 1970s, the emissions in China and India have started to increase dramatically at about the same time and have only recently started to stagnate due to new regulations in China. Here we use emission scenarios from the years 1996 through 2010 to assess the effect that these emissions have on local aerosol properties and climate as well as on the global climate. We use the aerosol-climate model ECHAM5-HAM [Roeckner2003, Roeckner2004] to simulate the local aerosol properties in China and India in the years 1996 through 2010, and their impact on local as well as global climate. For anthropogenic aerosol greenhouse gas emissions we use the ACCMIP-MACCity Aerocom emissions (Aerocom 2) [Lamarque2010] in combination with the emissions for China and India after Lu et. al [Lu2011] for the mentioned period of time. To assess the effect of anthropogenic aerosol emissions on earth's climate is assessed using the ECHAM-HAM model coupled to a mixed layer ocean on a T42L19 grid. The model is run with fixed yearly emissions for several emission scenarios (e.g. for the years 1996 and 2010), with data derived from 100-year averages. Additionally we run a number of transient simulations (i.e. with varying yearly emissions) from 1996 to 2010 in the attempt to extract a climate trend for the given period. References [Roeckner2003] Roeckner, E., Bäuml, R., Bonaventura, L., Brokopf

  5. Toxicological evaluation of realistic emission source aerosols (TERESA): summary and conclusions

    PubMed Central

    Godleski, John J.; Rohr, Annette C.; Coull, Brent A.; Kang, Choong-Min; Diaz, Edgar A.; Koutrakis, Petros

    2013-01-01

    The toxicological evaluation of realistic emissions of source aerosols (TERESA) study seeks to delineate health effects of aerosols formed from emissions of particulate matter sources. This series of papers reports the findings of experiments using coal-fired power plants as the source of emissions and this paper summarizes the findings and knowledge acquired from these studies. Emissions were drawn directly from the stacks of three coal-fired power plants in the US, and photochemically aged in a mobile laboratory to simulate downwind power plant plume processing. The power plants used different sources of coal and had different emission controls. Exposure scenarios included primary particles, secondary particles and mixtures of these with common atmospheric constituents (α-pinene and ammonia). Extensive exposure characterization was carried out, and toxicological outcomes were evaluated in Sprague-Dawley rats exposed to different emission scenarios. Breathing pattern, pulmonary inflammatory responses, in vivo pulmonary and cardiac chemiluminescence and cardiac response in a model of acute myocardial infarction were assessed. The results showed no response or relatively mild responses to the inhaled aerosols studied; complex scenarios which included oxidized emissions and α-pinene to simulate biogenic secondary organic aerosol tended to induce more statistically significant responses than scenarios of oxidized and non-oxidized emissions alone. Relating adverse effects to specific components did not consistently identify a toxic constituent. These findings are consistent with most of the previously published studies using pure compounds to model secondary power plant emissions, but importantly add substantial complexity and thus have considerable merit in defining toxicological responses. PMID:21913822

  6. Ion and aerosol precursor densities in Titan's ionosphere: A multi-instrument case study

    NASA Astrophysics Data System (ADS)

    Shebanits, O.; Wahlund, J.-E.; Edberg, N. J. T.; Crary, F. J.; Wellbrock, A.; Andrews, D. J.; Vigren, E.; Desai, R. T.; Coates, A. J.; Mandt, K. E.; Waite, J. H.

    2016-10-01

    The importance of the heavy ions and dust grains for the chemistry and aerosol formation in Titan's ionosphere has been well established in the recent years of the Cassini mission. In this study we combine independent in situ plasma (Radio Plasma and Wave Science Langmuir Probe (RPWS/LP)) and particle (Cassini Plasma Science Electron Spectrometer, Cassini Plasma Science Ion Beam Spectrometer, and Ion and Neutral Mass Spectrometer) measurements of Titan's ionosphere for selected flybys (T16, T29, T40, and T56) to produce altitude profiles of mean ion masses including heavy ions and develop a Titan-specific method for detailed analysis of the RPWS/LP measurements (applicable to all flybys) to further constrain ion charge densities and produce the first empirical estimate of the average charge of negative ions and/or dust grains. Our results reveal the presence of an ion-ion (dusty) plasma below 1100 km altitude, with charge densities exceeding the primary ionization peak densities by a factor ≥2 in the terminator and nightside ionosphere (ne/ni ≤ 0.1). We suggest that ion-ion (dusty) plasma may also be present in the dayside ionosphere below 900 km (ne/ni < 0.5 at 1000 km altitude). The average charge of the dust grains (≥1000 amu) is estimated to be between -2.5 and -1.5 elementary charges, increasing toward lower altitudes.

  7. Impact of Manaus City on the Amazon Green Ocean atmosphere: ozone production, precursor sensitivity and aerosol load

    NASA Astrophysics Data System (ADS)

    Kuhn, U.; Ganzeveld, L.; Thielmann, A.; Dindorf, T.; Schebeske, G.; Welling, M.; Sciare, J.; Roberts, G.; Meixner, F. X.; Kesselmeier, J.; Lelieveld, J.; Kolle, O.; Ciccioli, P.; Lloyd, J.; Trentmann, J.; Artaxo, P.; Andreae, M. O.

    2010-10-01

    As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001) field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry season transition period in July 2001. During the flights, we performed vertical stacks of crosswind transects in the urban outflow downwind of Manaus City, measuring a comprehensive set of trace constituents including O3, NO, NO2, CO, VOC, CO2, and H2O. Aerosol loads were characterized by concentrations of total aerosol number (CN) and cloud condensation nuclei (CCN), and by light scattering properties. Measurements over pristine rainforest areas during the campaign showed low levels of pollution from biomass burning or industrial emissions, representative of wet season background conditions. The urban plume of Manaus City was found to be joined by plumes from power plants south of the city, all showing evidence of very strong photochemical ozone formation. One episode is discussed in detail, where a threefold increase in ozone mixing ratios within the atmospheric boundary layer occurred within a 100 km travel distance downwind of Manaus. Observation-based estimates of the ozone production rates in the plume reached 15 ppb h-1. Within the plume core, aerosol concentrations were strongly enhanced, with ΔCN/ΔCO ratios about one order of magnitude higher than observed in Amazon biomass burning plumes. ΔCN/ΔCO ratios tended to decrease with increasing transport time, indicative of a significant reduction in particle number by coagulation, and without substantial new particle nucleation occurring within the time/space observed. While in the background atmosphere a large fraction of the total particle number served as CCN (about 60-80% at 0.6% supersaturation), the CCN/CN ratios within the plume indicated that only a small fraction (16±12%) of the plume particles were CCN

  8. Impact of Manaus City on the Amazon Green Ocean atmosphere: ozone production, precursor sensitivity and aerosol load

    NASA Astrophysics Data System (ADS)

    Kuhn, U.; Ganzeveld, L.; Thielmann, A.; Dindorf, T.; Schebeske, G.; Welling, M.; Sciare, J.; Roberts, G.; Meixner, F. X.; Kesselmeier, J.; Lelieveld, J.; Kolle, O.; Ciccioli, P.; Lloyd, J.; Trentmann, J.; Artaxo, P.; Andreae, M. O.

    2010-05-01

    As a contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001) field campaign in the heart of the Amazon Basin, we analyzed the temporal and spatial dynamics of the urban plume of Manaus City during the wet-to-dry season transition period in July 2001. During the flights, we performed vertical stacks of crosswind transects in the urban outflow downwind of Manaus City, measuring a comprehensive set of trace constituents including O3, NO, NO2, CO, VOC, CO2, and H2O. Aerosol loads were characterized by total aerosol number concentration (CN) and cloud condensation nuclei (CCN) concentrations, and light scattering properties. Measurements over pristine rainforest areas during the campaign showed low levels of pollution from biomass burning or industrial emissions, representative of wet season background conditions. The urban plume of Manaus City was found to be joined by plumes from power plants south of the city, all showing evidence of very strong photochemical ozone formation. One episode is discussed in detail, where a threefold increase in ozone mixing ratios in the atmospheric boundary layer occurred within a 100 km travel distance downwind of Manaus. Observation-based estimates of the ozone production rates in the plume reached 15 ppb h-1. Within the plume core, aerosol concentrations were strongly enhanced, with ΔCN/ΔCO ratios about one order of magnitude higher than observed in Amazon biomass burning plumes. ΔCN/ΔCO ratios tended to decrease with increasing transport time, indicative of a significant reduction in particle number by coagulation, and without substantial new particle nucleation occurring within the time/space observed. While in the background atmosphere a large fraction of the total particle number served as CCN (about 60-80% at 0.6% supersaturation), the CCN/CN ratios within the plume indicated that only a small fraction (16 ± 12%) of the plume particles were

  9. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions

    NASA Astrophysics Data System (ADS)

    Lacey, Forrest; Henze, Daven

    2015-11-01

    Cookstove use is globally one of the largest unregulated anthropogenic sources of primary carbonaceous aerosol. While reducing cookstove emissions through national-scale mitigation efforts has clear benefits for improving indoor and ambient air quality, and significant climate benefits from reduced green-house gas emissions, climate impacts associated with reductions to co-emitted black (BC) and organic carbonaceous aerosol are not well characterized. Here we attribute direct, indirect, semi-direct, and snow/ice albedo radiative forcing (RF) and associated global surface temperature changes to national-scale carbonaceous aerosol cookstove emissions. These results are made possible through the use of adjoint sensitivity modeling to relate direct RF and BC deposition to emissions. Semi- and indirect effects are included via global scaling factors, and bounds on these estimates are drawn from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. Absolute regional temperature potentials are used to estimate global surface temperature changes. Bounds are placed on these estimates, drawing from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. We estimate a range of 0.16 K warming to 0.28 K cooling with a central estimate of 0.06 K cooling from the removal of cookstove aerosol emissions. At the national emissions scale, countries’ impacts on global climate range from net warming (e.g., Mexico and Brazil) to net cooling, although the range of estimated impacts for all countries span zero given uncertainties in RF estimates and fuel characterization. We identify similarities and differences in the sets of countries with the highest emissions and largest cookstove temperature impacts (China, India, Nigeria, Pakistan, Bangladesh and Nepal), those with the largest temperature impact per carbon emitted (Kazakhstan, Estonia, and Mongolia), and those that would provide the

  10. Development of a model for characterizing pneumatically generated primary aerosols for inductively coupled plasma emission spectrometry

    SciTech Connect

    Msimanga, N.D.G.

    1992-01-01

    The study of aerosols plays a key role in the development of analytical atomic spectroscopy. While work has been carried out with Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) to improve transport efficiency, analyte signal, limits of detection, and to reduce matrix interferences, little study has focused on sample introduction processes. This study has focused on the characterization and optimization of pneumatic nebulizers used for liquid sample introduction to the ICP. Pneumatic nebulization is the most common means of sample introduction in atomic spectrometry. The pneumatic nebulizers most commonly used today for ICP spectrometry are the cross-flow type or all-glass concentric nebulizers. Aerosols undergo certain processes after the primary formation process before reaching the atomizer, the secondary and tertiary stages. In this work all three stages were looked at, focusing on the primary aerosols. The primary aerosol is the first stage in the formation of the aerosols and takes place at the tip of the nebulizer, as the liquid stream is shattered by the gas flow. The drop size diameters of primary aerosols were measured using a Fraunhofer Laser Diffraction instrument. The Sauter mean diameter (D3.2), which describes the volume of the aerosol with a given surface area, was determined for nebulizers at spray chambers operated under a variety of conditions. The characterization and optimization of sample introduction involved a study of aerosol technology, a study of different instruments for measuring the mean drop size, a description of the instrument, and the influence of some parameters on the D3.2. An empirical model summarizing the characteristics of the primary aerosols is proposed. Modeling is carried out using nonlinear software. The data for modelling were acquired using water, n-butanol, and methanol as the liquid solvents. The model was tested on data obtained from nebulizers with different cross-sectional areas.

  11. Profile and Morphology of Fungal Aerosols Characterized by Field Emission Scanning Electron Microscopy (FESEM)

    PubMed Central

    Afanou, Komlavi Anani; Straumfors, Anne; Skogstad, Asbjørn; Skaar, Ida; Hjeljord, Linda; Skare, Øivind; Green, Brett James; Tronsmo, Arne; Eduard, Wijnand

    2016-01-01

    Fungal aerosols consist of spores and fragments with diverse array of morphologies; however, the size, shape, and origin of the constituents require further characterization. In this study, we characterize the profile of aerosols generated from Aspergillus fumigatus, A. versicolor, and Penicillium chrysogenum grown for 8 weeks on gypsum boards. Fungal particles were aerosolized at 12 and 20 L min−1 using the Fungal Spore Source Strength Tester (FSSST) and the Stami particle generator (SPG). Collected particles were analyzed with field emission scanning electron microscopy (FESEM). We observed spore particle fraction consisting of single spores and spore aggregates in four size categories, and a fragment fraction that contained submicronic fragments and three size categories of larger fragments. Single spores dominated the aerosols from A. fumigatus (median: 53%), while the submicronic fragment fraction was the highest in the aerosols collected from A. versicolor (median: 34%) and P. chrysogenum (median: 31%). Morphological characteristics showed near spherical particles that were only single spores, oblong particles that comprise some spore aggregates and fragments (<3.5 μm), and fiber-like particles that regroup chained spore aggregates and fragments (>3.5 μm). Further, the near spherical particles dominated the aerosols from A. fumigatus (median: 53%), while oblong particles were dominant in the aerosols from A. versicolor (68%) and P. chrysogenum (55%). Fiber-like particles represented 21% and 24% of the aerosols from A. versicolor and P. chrysogenum, respectively. This study shows that fungal particles of various size, shape, and origin are aerosolized, and supports the need to include a broader range of particle types in fungal exposure assessment. PMID:26855468

  12. Profile and Morphology of Fungal Aerosols Characterized by Field Emission Scanning Electron Microscopy (FESEM).

    PubMed

    Afanou, Komlavi Anani; Straumfors, Anne; Skogstad, Asbjørn; Skaar, Ida; Hjeljord, Linda; Skare, Øivind; Green, Brett James; Tronsmo, Arne; Eduard, Wijnand

    Fungal aerosols consist of spores and fragments with diverse array of morphologies; however, the size, shape, and origin of the constituents require further characterization. In this study, we characterize the profile of aerosols generated from Aspergillus fumigatus, A. versicolor, and Penicillium chrysogenum grown for 8 weeks on gypsum boards. Fungal particles were aerosolized at 12 and 20 L min(-1) using the Fungal Spore Source Strength Tester (FSSST) and the Stami particle generator (SPG). Collected particles were analyzed with field emission scanning electron microscopy (FESEM). We observed spore particle fraction consisting of single spores and spore aggregates in four size categories, and a fragment fraction that contained submicronic fragments and three size categories of larger fragments. Single spores dominated the aerosols from A. fumigatus (median: 53%), while the submicronic fragment fraction was the highest in the aerosols collected from A. versicolor (median: 34%) and P. chrysogenum (median: 31%). Morphological characteristics showed near spherical particles that were only single spores, oblong particles that comprise some spore aggregates and fragments (<3.5 μm), and fiber-like particles that regroup chained spore aggregates and fragments (>3.5 μm). Further, the near spherical particles dominated the aerosols from A. fumigatus (median: 53%), while oblong particles were dominant in the aerosols from A. versicolor (68%) and P. chrysogenum (55%). Fiber-like particles represented 21% and 24% of the aerosols from A. versicolor and P. chrysogenum, respectively. This study shows that fungal particles of various size, shape, and origin are aerosolized, and supports the need to include a broader range of particle types in fungal exposure assessment.

  13. The Influence of Anthropogenic Sources on Fluxes of Secondary Organic Aerosol Precursors From a Deciduous Forest in the Southeastern United States

    NASA Astrophysics Data System (ADS)

    Saylor, R. D.; Stein, A. F.

    2012-12-01

    The dynamic, bi-directional exchange of trace chemical species between forests and the atmosphere has important impacts on both the forest ecosystem and atmospheric composition, with potentially profound consequences on air quality, climate and global ecosystem functioning. Forests are a dominant source of biogenic volatile organic compound (BVOC) emissions into the earth's atmosphere and thus play an important role in the formation of secondary organic aerosol (SOA). To arrive at a better scientific understanding of the complex chemical and physical processes of forest-atmosphere exchange and provide a platform for robust analysis of field measurements of these processes, a process-level, multiphase model of the atmospheric chemistry and physics of forest canopies is being developed. This model, the Atmospheric Chemistry and Canopy Exchange Simulation System (ACCESS) is being used to investigate various aspects of forest-atmosphere exchange and chemistry including gas, aqueous and aerosol phases. ACCESS currently includes processes accounting for the emission of BVOCs from the canopy, turbulent vertical transport within and above the canopy and throughout the height of the planetary boundary layer, detailed chemical reactions, mixing with the background atmosphere and bi-directional exchange between the atmosphere and the canopy and the forest floor. The Walker Branch Watershed (WBW) is a dedicated ecosystem research area on the U. S. Department of Energy's Oak Ridge Reservation in eastern Tennessee. The 97.5 ha watershed has been the site of long-term ecosystem and atmospheric research activities since the mid-1960's. A flux tower located within the watershed (35°57'30"N, 84°17'15"W; 365 m above mean sea level) and 10 km southwest of Oak Ridge, Tennessee, has served as a focal point for previous atmospheric turbulence and chemical flux measurements and the canopy morphology of the forest surrounding the flux tower has been extensively documented. The forest is

  14. Use of MODIS-Derived Fire Radiative Energy to Estimate Smoke Aerosol Emissions over Different Ecosystems

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Kaufman, Yoram J.

    2003-01-01

    Biomass burning is the main source of smoke aerosols and certain trace gases in the atmosphere. However, estimates of the rates of biomass consumption and emission of aerosols and trace gases from fires have not attained adequate reliability thus far. Traditional methods for deriving emission rates employ the use of emission factors e(sub x), (in g of species x per kg of biomass burned), which are difficult to measure from satellites. In this era of environmental monitoring from space, fire characterization was not a major consideration in the design of the early satellite-borne remote sensing instruments, such as AVHRR. Therefore, although they are able to provide fire location information, they were not adequately sensitive to variations in fire strength or size, because their thermal bands used for fire detection saturated at the lower end of fire radiative temperature range. As such, hitherto, satellite-based emission estimates employ proxy techniques using satellite derived fire pixel counts (which do not express the fire strength or rate of biomass consumption) or burned areas (which can only be obtained after the fire is over). The MODIS sensor, recently launched into orbit aboard EOS Terra (1999) and Aqua (2002) satellites, have a much higher saturation level and can, not only detect the fire locations 4 times daily, but also measures the at-satellite fire radiative energy (which is a measure of the fire strength) based on its 4 micron channel temperature. Also, MODIS measures the optical thickness of smoke and other aerosols. Preliminary analysis shows appreciable correlation between the MODIS-derived rates of emission of fire radiative energy and smoke over different regions across the globe. These relationships hold great promise for deriving emission coefficients, which can be used for estimating smoke aerosol emissions from MODIS active fire products. This procedure has the potential to provide more accurate emission estimates in near real

  15. Direct Radiative Forcing Due to Carbonaceous Aerosols in Biomass Burning Emissions

    NASA Astrophysics Data System (ADS)

    Saleh, R.; Marks, M.; Heo, J.; Adams, P. J.; Donahue, N. M.; Robinson, A. L.

    2014-12-01

    Most climate forcing calculations treat black carbon (BC) as the only carbonaceous particulate light-absorber. Numerous studies have shown that some organic aerosols (OA), mainly associated with biomass burning emissions, contain significant amounts of light-absorbing brown carbon (BrC). However, the light absorption properties of biomass burning OA are poorly constrained, complicating its representation in climate models. During the Fire Laboratory at Missoula Experiment (FLAME 4), we conducted experiments to characterize the light absorption properties of OA in emissions of globally important biomass fuels. We showed that the effective absorptivity of OA depends largely on burn conditions, not fuel type, and derived a parameterization that links OA absorptivity to the BC-to-OA ratio of the emissions (Nature Geoscience, DOI:10.1038/ngeo2220). Here, we utilize this parameterization to estimate the direct radiative effect (DRE) of carbonaceous aerosols in biomass burning emissions using a global chemical transport model (GEOS-Chem) and a column radiative transfer model (libRadTran). The simulations were performed for the year 2005. Monthly-averaged global aerosol concentrations, including BC, OA, inorganic sulfates and nitrates, sea salt, and mineral dust, were obtained from GEOS-Chem simulations. Concentrations of BC and OA from biomass burning emissions were determined by running two GEOS-Chem simulations, one with and one without biomass burning emissions. We attributed the difference in BC and OA concentrations between the two simulations to biomass burning, and could thus calculate the BC-to-OA ratio for biomass burning emissions. libRadTran was used (offline) to calculated DRE due to biomass burning carbonaceous aerosols at each GEOS-Chem grid-cell. Our results show that the global average DRE due to carbonaceous biomass burning emissions increases significantly if light-absorption by OA is considered (using our parameterization for OA absorptivity), compared

  16. TOTAL PARTICLE, SULFATE, AND ACIDIC AEROSOL EMISSIONS FROM KEROSENE SPACE HEATERS

    EPA Science Inventory

    Chamber studies were conducted on four unvented kerosene space heaters to assess emissions of total particle, sulfate, and acidic aerosol. The heaters tested represented four burner designs currently in use by the public. Kerosene space heaters are a potential source of fine part...

  17. Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model

    EPA Science Inventory

    Sea spray aerosols (SSA) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. In this study, the Community Multiscale Air Quality (CMAQ) model is updated to enhance fine mode SSA emissions,...

  18. Secondary aerosol formation from stress-induced biogenic emissions and possible climate feedbacks

    NASA Astrophysics Data System (ADS)

    Mentel, Th. F.; Kleist, E.; Andres, S.; Dal Maso, M.; Hohaus, T.; Kiendler-Scharr, A.; Rudich, Y.; Springer, M.; Tillmann, R.; Uerlings, R.; Wahner, A.; Wildt, J.

    2013-09-01

    Atmospheric aerosols impact climate by scattering and absorbing solar radiation and by acting as ice and cloud condensation nuclei. Biogenic secondary organic aerosols (BSOAs) comprise an important component of atmospheric aerosols. Biogenic volatile organic compounds (BVOCs) emitted by vegetation are the source of BSOAs. Pathogens and insect attacks, heat waves and droughts can induce stress to plants that may impact their BVOC emissions, and hence the yield and type of formed BSOAs, and possibly their climatic effects. This raises questions of whether stress-induced changes in BSOA formation may attenuate or amplify effects of climate change. In this study we assess the potential impact of stress-induced BVOC emissions on BSOA formation for tree species typical for mixed deciduous and Boreal Eurasian forests. We studied the photochemical BSOA formation for plants infested by aphids in a laboratory setup under well-controlled conditions and applied in addition heat and drought stress. The results indicate that stress conditions substantially modify BSOA formation and yield. Stress-induced emissions of sesquiterpenes, methyl salicylate, and C17-BVOCs increase BSOA yields. Mixtures including these compounds exhibit BSOA yields between 17 and 33%, significantly higher than mixtures containing mainly monoterpenes (4-6% yield). Green leaf volatiles suppress SOA formation, presumably by scavenging OH, similar to isoprene. By classifying emission types, stressors and BSOA formation potential, we discuss possible climatic feedbacks regarding aerosol effects. We conclude that stress situations for plants due to climate change should be considered in climate-vegetation feedback mechanisms.

  19. Characterizing the impact of urban emissions on regional aerosol particles; airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouch, N.; Pichon, J.-M.; Prévôt, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2013-09-01

    The MEGAPOLI experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS) giving detailed information of the non-refractory submicron aerosol species. The mass concentration of BC, measured by a particle absorption soot photometer (PSAP), was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA), black carbon and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (-log(NOx / NOy). Plotting the equivalent ratios for the Positive Matrix Factorization (PMF) resolved species (LV-OOA, SV-OOA, and HOA) illustrate that the increase in OA is a result of secondary organic aerosol (SOA). Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in Mexico city, Mexico and in New England, USA. Using the measured VOCs species together with recent organic aerosol formation yields we predicted ~ 50% of the measured organics. These airborne measurements during the MEGAPOLI experiment show that urban emissions contribute to the formation of OA

  20. Basic biogenic aerosol precursors: Agricultural source attribution of volatile amines revised

    NASA Astrophysics Data System (ADS)

    Kuhn, U.; Sintermann, J.; Spirig, C.; Jocher, M.; Ammann, C.; Neftel, A.

    2011-08-01

    Despite recent evidence on an important role of volatile amines in the nucleation of particulate matter, very scarce information is available on their atmospheric abundance and source distribution. Previous measurements in animal housings had identified livestock husbandry as the main amine source, with trimethylamine (TMA) being the key component. This has led to the assumption that the agricultural sources for amines are similar as for ammonia, emitted throughout the cascade of animal excretion, storage and application in the field. In this study, we present the first micrometeorological flux measurements as well as dynamic enclosure experiments showing that the amine source strength from stored slurry is negligible, implying significant consequences for the global amine emission inventory. In the case of cattle, amine production is attributed to the animal's rumination activity and exhalation is suggested to be an important emission pathway, similar to the greenhouse gas methane. Fodder like hay and silage also emits volatile amines, potentially assigning these alkaloid compounds a key function in enhancing particle formation in remote areas.

  1. Inventory of aerosol and sulphur dioxide emissions from India. Part II—biomass combustion

    NASA Astrophysics Data System (ADS)

    Reddy, M. Shekar; Venkataraman, Chandra

    A spatially resolved biomass burning data set, and related emissions of sulphur dioxide and aerosol chemical constituents was constructed for India, for 1996-1997 and extrapolated to the INDOEX period (1998-1999). Sources include biofuels (wood, crop waste and dung-cake) and forest fires (accidental, shifting cultivation and controlled burning). Particulate matter (PM) emission factors were compiled from studies of Indian cooking stoves and from literature for open burning. Black carbon (BC) and organic matter (OM) emissions were estimated from these, accounting for combustion temperatures in cooking stoves. Sulphur dioxide emission factors were based on fuel sulphur content and reported literature measurements. Biofuels accounted 93% of total biomass consumption (577 MT yr -1), with forest fires contributing only 7%. The national average biofuel mix was 56 : 21 : 23% of fuelwood, crop waste and dung-cake, respectively. Compared to fossil fuels, biomass combustion was a minor source of SO 2 (7% of total), with higher emissions from dung-cake because of its higher sulphur content. PM 2.5 emissions of 2.04 Tg yr -1 with an "inorganic fraction" of 0.86 Tg yr -1 were estimated. Biomass combustion was the major source of carbonaceous aerosols, accounting 0.25 Tg yr -1 of BC (72% of total) and 0.94 Tg yr -1 of OM (76% of total). Among biomass, fuelwood and crop waste were primary contributors to BC emissions, while dung-cake and forest fires were primary contributors to OM emissions. Northern and the east-coast India had high densities of biomass consumption and related emissions. Measurements of emission factors of SO 2, size resolved aerosols and their chemical constituents for Indian cooking stoves are needed to refine the present estimates.

  2. Secondary organic aerosol formation from gasoline vehicle emissions in a new mobile environmental reaction chamber

    NASA Astrophysics Data System (ADS)

    Platt, S. M.; El Haddad, I.; Zardini, A. A.; Clairotte, M.; Astorga, C.; Wolf, R.; Slowik, J. G.; Temime-Roussel, B.; Marchand, N.; Ježek, I.; Drinovec, L.; Močnik, G.; Möhler, O.; Richter, R.; Barmet, P.; Bianchi, F.; Baltensperger, U.; Prévôt, A. S. H.

    2012-10-01

    We present a new mobile environmental reaction chamber for the simulation of the atmospheric aging of aerosols from different emissions sources without limitation from the instruments or facilities available at any single site. The chamber can be mounted on a trailer for transport to host facilities or for mobile measurements. Photochemistry is simulated using a set of 40 UV lights (total power 4 KW). Characterisation of the emission spectrum of these lights shows that atmospheric photochemistry can be accurately simulated over a range of temperatures from -7-25 °C. A photolysis rate of NO2, JNO2, of (8.0 ± 0.7) × 10-3 molecules cm-3 s-1 was determined at 25 °C. Further, we present the first application of the mobile chamber and demonstrate its utility by quantifying primary organic aerosol (POA) emission and secondary organic aerosol (SOA) production from a Euro 5 light duty gasoline vehicle. Exhaust emissions were sampled during the New European Driving Cycle (NEDC), the standard driving cycle for European regulatory purposes, and injected into the chamber. The relative concentrations of oxides of nitrogen (NOx) and total hydrocarbon (THC) during the aging of emissions inside the chamber were controlled using an injection system developed as a part of the new mobile chamber set up. Total OA (POA + SOA) emission factors of (370 ± 18) × 10-3 g kg-1 fuel, or (14.6 ± 0.8) × 10-3 g km-1, after aging, were calculated from concentrations measured inside the smog chamber during two experiments. The average SOA/POA ratio for the two experiments was 15.1, a much larger increase than has previously been seen for diesel vehicles, where smog chamber studies have found SOA/POA ratios of 1.3-1.7. Due to this SOA formation, carbonaceous particulate matter (PM) emissions from a gasoline vehicle may approach those of a diesel vehicle of the same class. Furthermore, with the advent of emission controls requiring the use of diesel particle filters, gasoline vehicle emissions

  3. Secondary aerosol formation from stress-induced biogenic emissions and possible climate feedbacks

    NASA Astrophysics Data System (ADS)

    Mentel, Th. F.; Kleist, E.; Andres, S.; Maso, M. D.; Hohaus, T.; Kiendler-Scharr, A.; Rudich, Y.; Springer, M.; Tillmann, R.; Uerlings, R.; Wahner, A.; Wildt, J.

    2013-03-01

    Atmospheric aerosols impact climate by scattering and absorbing solar radiation and by acting as ice and cloud condensation nuclei. Secondary organic aerosols (SOA) comprise an important component of atmospheric aerosols. Biogenic volatile organic compounds (BVOC) emitted by vegetation are a major source of SOA. Pathogens and insect attacks, heat waves and droughts can induce stress to plants that may impact their BVOC emissions, and hence the yield and type of formed SOA, and possibly their climatic effects. This raises questions whether stress-induced changes in SOA formation may attenuate or amplify effects of climate change. In this study we assess the potential impact of stress-induced BVOC emissions on SOA formation for tree species typical for mixed deciduous and Boreal Eurasian forests. We studied the photochemical SOA formation for infested plants in a laboratory setup under well-controlled conditions and applied in addition heat and drought stress. The results indicate that stress conditions substantially modify SOA formation. While sesquiterpenes, methyl salicylate, and C17-BVOC increase SOA yield, green leaf volatiles suppress SOA formation. By classifying emission types, stressors and SOA formation potential, we propose possible climatic feedbacks regarding aerosol effects. We conclude that stress situations for plants due to climate change should be considered in climate-vegetation feedback mechanisms.

  4. Optical properties of aerosol emissions from biomass burning in the tropics, BASE-A

    NASA Technical Reports Server (NTRS)

    Holben, Brent N.; Kaufman, Yoram J.; Setzer, Alberto W.; Tanre, Didre D.; Ward, Darold E.

    1991-01-01

    Ground-based and airborne measurements of biomass-burning smoke particle optical properties, obtained with a view to aerosol-absorption properties, are presented as a function of time and atmospheric height. The wavelength dependence of the optical thickness can be explained by a log-normal size distribution, with particles' effective radius varying between 0.1 and 0.2 microns. The strong correlation noted between aerosol particle profile and CO profile indicates that smoke particulates constitute a good tracer for emission trace gases from tropical biomass burning.

  5. The chemical and microphysical properties of secondary organic aerosols from Holm Oak emissions

    NASA Astrophysics Data System (ADS)

    Lang-Yona, N.; Rudich, Y.; Mentel, Th. F.; Bohne, A.; Buchholz, A.; Kiendler-Scharr, A.; Kleist, E.; Spindler, C.; Tillmann, R.; Wildt, J.

    2010-08-01

    The Mediterranean region is expected to experience substantial climatic change in the next 50 years. But, possible effects of climate change on biogenic volatile organic compound (VOC) emissions as well as on the formation of secondary organic aerosols (SOA) produced from these VOC are yet unexplored. To address such issues, the effects of temperature on the VOC emissions of Mediterranean Holm Oak and small Mediterranean stand of Wild Pistacio, Aleppo Pine, and Palestine Oak have been studied in the Jülich plant aerosol atmosphere chamber. For Holm Oak the optical and microphysical properties of the resulting SOA were investigated. Monoterpenes dominated the VOC emissions from Holm Oak (97.5%) and Mediterranean stand (97%). Higher temperatures enhanced the overall VOC emission but with different ratios of the emitted species. The amount of SOA increased linearly with the emission strength with a fractional mass yield of 6.0±0.6%, independent of the detailed emission pattern. The investigated particles were highly scattering with no absorption abilities. Their average hygroscopic growth factor of 1.13±0.03 at 90% RH with a critical diameter of droplet activation was 100±4 nm at a supersaturation of 0.4%. All microphysical properties did not depend on the detailed emission pattern, in accordance with an invariant O/C ratio (0.57(+0.03/-0.1)) of the SOA observed by high resolution aerosol mass spectrometry. The increase of Holm oak emissions with temperature (≈20% per degree) was stronger than e.g. for Boreal tree species (≈10% per degree). The SOA yield for Mediterranean trees determined here is similar as for Boreal trees. Increasing mean temperature in Mediterranean areas could thus have a stronger impact on BVOC emissions and SOA formation than in areas with Boreal forests.

  6. Inverse Compton emission from a cosmic-ray precursor in RX J1713.7-3946

    NASA Astrophysics Data System (ADS)

    Ohira, Yutaka; Yamazaki, Ryo

    2017-03-01

    Recently, the High Energy Stereoscopic System (H.E.S.S.) reported two new interesting results for a γ-ray emitting supernova remnant, RX J1713.7-3946 (G347.3-0.5). The first result is the establishment of a broken power-law spectrum of GeV-TeV γ-rays. The other is a more extended γ-ray spatial profile than the one in the X-ray band. In this paper, we show both of these results can be explained by inverse Compton emission from accelerated electrons. If the maximum energy of electrons being accelerated decreases with time, the broken power-law spectrum can be generated by accumulation. Furthermore, the extended component of γ-ray profile can be interpreted as a CR precursor of currently accelerated electrons.

  7. Inverse modeling of biomass burning emissions using Total Ozone Mapping Spectrometer aerosol index for 1997

    NASA Astrophysics Data System (ADS)

    Zhang, Sophia; Penner, Joyce E.; Torres, Omar

    2005-11-01

    We present results from an inverse model study to determine biomass smoke emissions for the year 1997 by comparison of modeled aerosol index (AI) with that measured by the EP TOMS instrument. The IMPACT model with Data Assimilation Office (DAO) meteorology data in 1997 is utilized to obtain aerosol spatial and temporal distributions. Then a radiative transfer model is applied to generate the modeled AI. A Bayesian inverse technique is applied to optimize the difference between the modeled AI and the EP TOMS AI in the same period by regulating monthly a priori biomass smoke emissions in seven predefined regions. The modeled AI with a posteriori emissions is generally in better agreement with the EP TOMS AI. The a posteriori emissions from Indonesia increase by a factor of 8-10 over the a priori emissions due to the Indonesian fires in 1997. The annual total a posteriori source increases by about 13% for the year 1997 (6.31 Tg/yr black carbon and 67.27 Tg/yr smoke) in the base scenario, with a larger adjustment of monthly emissions. The sensitivity of this result to the a priori uncertainties, the height of the smoke layer, the cloud screening criteria, the inclusion of an adjustment of emissions outside the main biomass burning regions, and the inclusion of the covariances between observations in different locations is discussed in a set of sensitivity scenarios. The sensitivity scenarios suggest that the inverse model results are most sensitive to the assumed uncertainty for a priori emissions and the altitude of aerosol layer in the model and are less sensitive to other factors. In the scenario where the uncertainty of a priori emissions is increased to 100% (300% in Indonesia), the total annual black carbon emission is increased to 6.87 Tg/yr, and the smoke emission increases to 73.39 Tg/yr. The a posteriori emissions in Indonesia in the scenario with increased uncertainty are in better agreement with both the TOMS AI and with previous estimates for the

  8. Cardiac and pulmonary oxidative stress in rats exposed to realistic emissions of source aerosols

    PubMed Central

    Lemos, Miriam; Diaz, Edgar A.; Gupta, Tarun; Kang, Choong-Min; Ruiz, Pablo; Coull, Brent A.; Godleski, John J.; Gonzalez-Flecha, Beatriz

    2013-01-01

    In vivo chemiluminescence (CL) is a measure of reactive oxygen species in tissues. CL was used to assess pulmonary and cardiac responses to inhaled aerosols derived from aged emissions of three coal-fired power plants in the USA. Sprague–Dawley rats were exposed to either filtered air or: (1) primary emissions (P); (2) ozone oxidized emissions (PO); (3) oxidized emissions + secondary organic aerosol (SOA) (POS); (4) neutralized oxidized emissions + SOA (PONS); and (5) control scenarios: oxidized emissions + SOA in the absence of primary particles (OS), oxidized emissions alone (O), and SOA alone (S). Immediately after 6 hours of exposure, CL in the lung and heart was measured. Tissues were also assayed for thiobarbituric acid reactive substances (TBARS). Exposure to P or PO aerosols led to no changes compared to filtered air in lung or heart CL at any individual plant or when all data were combined. POS caused significant increases in lung CL and TBARS at only one plant, and not in combined data from all plants; PONS resulted in increased lung CL only when data from all plants were combined. Heart CL was also significantly increased with exposure to POS only when data from all plants were combined. PONS increased heart CL significantly in one plant with TBARS accumulation, but not in combined data. Exposure to O, OS, and S had no CL effects. Univariate analyses of individual measured components of the exposure atmospheres did not identify any component associated with increased CL. These data suggest that coal-fired power plant emissions combined with other atmospheric constituents produce limited pulmonary and cardiac oxidative stress. PMID:21913821

  9. Ethylene glycol emissions from on-road vehicles: implications for aqueous phase secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Wood, E. C.; Knighton, W. B.; Fortner, E.; Herndon, S. C.; Onasch, T. B.; Franklin, J.; Harley, R. A.; Gentner, D. R.; Goldstein, A. H.

    2012-12-01

    Ethylene glycol (HOCH2CH2OH), used as an engine coolant for most on-road vehicles, is an intermediate volatility organic compound (IVOC) with a high Henry's Law Coefficient (kH > 10,000 M atm-1) . Oxidation of ethylene glycol, especially in the atmospheric aqueous phase (clouds, fog, wet aerosol), can lead to the formation of glycolaldehyde, oxalic acid, and ultimately secondary organic aerosol. We present measurements of unexpectedly high ethylene glycol emissions in the Caldecott Tunnel near San Francisco (Summer 2010) and the Washburn Tunnel near Houston (Spring 2009). Ethylene glycol was detected using a proton-transfer reaction mass spectrometer (PTR-MS) at m/z = 45, which is usually interpreted as acetaldehyde. Although not necessarily a tailpipe emission, effective fuel-based emission factors are calculated using the carbon balance method and range from 50 to 400 mg ethylene glycol per kg fuel. Total US and global emissions are estimated using these emission factors and fuel consumption rates and are compared to previous model estimates of ethylene glycol emissions (e.g., the Regional Atmospheric Chemistry Model). Compared to biogenically emitted isoprene, ethylene glycol is likely a minor source of glycolaldehyde globally, but may contribute significantly to glycolaldehyde, oxalate and SOA formation in areas dominated by urban emissions.

  10. Sulfur-rich geothermal emissions elevate acid aerosol levels in metropolitan Taipei.

    PubMed

    Lin, Chih-Hung; Mao, I-Fang; Tsai, Pei-Hsien; Chuang, Hsin-Yi; Chen, Yi-Ju; Chen, Mei-Lien

    2010-08-01

    Several studies have demonstrated that millions of people globally are potentially exposed to volcanic gases. Hydrogen sulfide is a typical gas in volcanic and geothermal areas. The gas is toxic at high concentrations that predominantly affects the nervous, cardiovascular, and respiratory systems. The WHO air quality guideline for hydrogen sulfide is 150 microg m(-3) (105 ppb). The northwest part of Taipei is surrounded by sulfur-rich geothermal and hot springs. Active fumaroles and bubbling springs around the geothermal area emit acidic gases. In combination with automobile emissions, the pollution of acid aerosols is characteristic of the metropolis. This study considered sulfur-rich geothermal, suburban and downtown locations of this metropolis to evaluate geothermally emitted acid aerosol and H(2)S pollution. Acid aerosols were collected using a honeycomb denuder filter pack sampling system (HDS), and then analyzed by ion chromatography (IC). Results indicated that long-term geothermal emissions, automobile emissions and photochemical reactions have led to significant variations in air pollution among regions of metropolitan Taipei. The highest H(2)S concentration was 1705 ppb in the geothermal area with low traffic density and the mean concentration was 404.06 ppb, which was higher than WHO guideline and might cause eye irritation. The SO(2) concentrations were relatively low (mean concentration was 3.9 ppb) in this area. It may partially result from the chemical reduction reaction in the geothermal emission, which converted the SO(2) gas into SO(4)(2-) and H(2)S. Consequently, very high sulfate concentrations (mean concentration higher than 25.0 microg m(-3)) were also observed in the area. The geothermal areas also emitted relatively high levels of aerosol acidity, Cl(-), F(-), PO(4)(3-), and N-containing aerosols. As a result, concentrations of HNO(3), NO(2)(-), PO(4)(3-), and SO(4)(2-) in metropolitan Taipei are significantly higher than those in other

  11. Airborne Measurements of Aerosol Emissions From the Alberta Oil Sands Complex

    NASA Astrophysics Data System (ADS)

    Howell, S. G.; Clarke, A. D.; McNaughton, C. S.; Freitag, S.

    2012-12-01

    The Alberta oil sands contain a vast reservoir of fossil hydrocarbons. The extremely viscous bitumen requires significant energy to extract and upgrade to make a fluid product suitable for pipelines and further refinement. The mining and upgrading process constitute a large industrial complex in an otherwise sparsely populated area of Canada. During the ARCTAS project in June/July 2008, while studying forest fire plumes, the NASA DC-8 and P-3B flew through the plume a total of 5 times. Once was a coordinated visit by both aircraft; the other 3 were fortuitous passes downwind. One study has been published about gas emissions from the complex. Here we concentrate on aerosol emissions and aging. As previously reported, there appear to be at least 2 types of plumes produced. One is an industrial-type plume with vast numbers of ultrafine particles, SO2, sulfate, black carbon (BC), CO, and NO2. The other, probably from the mining, has more organic aerosol and BC together with dust-like aerosols at 3 μm and a 1 μm mode of unknown origin. The DC-8 crossed the plume about 10 km downwind of the industrial site, giving time for the boundary layer to mix and enabling a very crude flux calculation suggesting that sulfate and organic aerosols were each produced at about 500 g/s (estimated errors are a factor of 2, chiefly due to concerns about vertical mixing). Since this was a single flight during a project dedicated to other purposes and operating conditions and weather may change fluxes considerably, this may not be a typical flux. As the plume progresses downwind, the ultrafine particles grow to sizes effective as cloud condensation nucei (CCN), SO2 is converted to sulfate, and organic aerosol is produced. During fair weather in the summer, as was the case during these flights, cloud convection pumps aerosol above the mixed layer. While the aerosol plume is difficult to detect from space, NO2 is measured by the OMI instrument an the Aura satellite and the oil sands plume

  12. The effect of future reduction in aerosol emissions on climate extremes in China

    NASA Astrophysics Data System (ADS)

    Wang, Zhili; Lin, Lei; Yang, Meilin; Xu, Yangyang

    2016-11-01

    This study investigates the effect of reduced aerosol emissions on projected temperature and precipitation extremes in China during 2031-2050 and 2081-2100 relative to present-day conditions using the daily data output from the Community Earth System Model ensemble simulations under the Representative Concentration Pathway (RCP) 8.5 with an applied aerosol reduction and RCP8.5 with fixed 2005 aerosol emissions (RCP8.5_FixA) scenarios. The reduced aerosol emissions of RCP8.5 magnify the warming effect due to greenhouse gases (GHG) and lead to significant increases in temperature extremes, such as the maximum of daily maximum temperature (TXx), minimum of daily minimum temperature (TNn), and tropical nights (TR), and precipitation extremes, such as the maximum 5-day precipitation amount, number of heavy precipitation days, and annual total precipitation from days ˃95th percentile, in China. The projected TXx, TNn, and TR averaged over China increase by 1.2 ± 0.2 °C (4.4 ± 0.2 °C), 1.3 ± 0.2 °C (4.8 ± 0.2 °C), and 8.2 ± 1.2 (30.9 ± 1.4) days, respectively, during 2031-2050 (2081-2100) under the RCP8.5_FixA scenario, whereas the corresponding values are 1.6 ± 0.1 °C (5.3 ± 0.2 °C), 1.8 ± 0.2 °C (5.6 ± 0.2 °C), and 11.9 ± 0.9 (38.4 ± 1.0) days under the RCP8.5 scenario. Nationally averaged increases in all of those extreme precipitation indices above due to the aerosol reduction account for more than 30 % of the extreme precipitation increases under the RCP8.5 scenario. Moreover, the aerosol reduction leads to decreases in frost days and consecutive dry days averaged over China. There are great regional differences in changes of climate extremes caused by the aerosol reduction. When normalized by global mean surface temperature changes, aerosols have larger effects on temperature and precipitation extremes over China than GHG.

  13. Ozone sensitivity to its precursor emissions in northeastern Mexico for a summer air pollution episode.

    PubMed

    Sierra, A; Vanoye, A Y; Mendoza, A

    2013-10-01

    A summer episode was modeled to address the expected response of ambient air O3 to hypothetical emission control scenarios in northeastern Mexico, and in particular in the Monterrey Metropolitan Area (MMA). This region is of interest because the MMA holds one of the worst air quality problems in the country and levels of air pollutants in the rest of northeastern Mexico are starting to be a concern. The MM5-SMOKE-CMAQ platform was used to conduct the numerical experiments. Twenty-four control scenarios were evaluated, combining the level of emission controls of O3 precursors (NO(x) and volatile organic compounds [VOCs]) from 0% to 50%. For the MMA, VOC-only controls result in the best option to reduce O3 concentrations, though the benefit is limited to the urban core. This same strategy results in negligible benefits for the rest of northeastern Mexico. NO(x) controls result in an increase in O3 concentration within the MMA of up to 20 ppbv and a decrease at downwind locations of up to 11 ppbv, with respect to the base-case scenario. Indicator ratios were also used to probe for NO(x)-sensitive and VOC-sensitive areas. Locations with an important influence of NO(x) point sources (i.e., Monclova and Nava/Acuña) are quite sensitive to changes in NO(x) emissions. Border cities in the Rio Bravo/Grande Valley tend to be marginally NO(x)-sensitive. Overall, the MMA seems to be dominated by a VOC-sensitive regime, while the rest of the region would tend to have a NO(x)-sensitive response. The results obtained serve to expand the current knowledge on the chemical regimes that dominate this region (VOC- or NO(x)-sensitive), and thus could help guide public policies related to emission regional control strategies.

  14. Direct observation of aqueous secondary organic aerosol from biomass-burning emissions

    NASA Astrophysics Data System (ADS)

    Gilardoni, Stefania; Massoli, Paola; Paglione, Marco; Giulianelli, Lara; Carbone, Claudio; Rinaldi, Matteo; Decesari, Stefano; Sandrini, Silvia; Costabile, Francesca; Gobbi, Gian Paolo; Chiara Pietrogrande, Maria; Visentin, Marco; Scotto, Fabiana; Fuzzi, Sandro; Facchini, Maria Cristina

    2016-09-01

    The mechanisms leading to the formation of secondary organic aerosol (SOA) are an important subject of ongoing research for both air quality and climate. Recent laboratory experiments suggest that reactions taking place in the atmospheric liquid phase represent a potentially significant source of SOA mass. Here, we report direct ambient observations of SOA mass formation from processing of biomass-burning emissions in the aqueous phase. Aqueous SOA (aqSOA) formation is observed both in fog water and in wet aerosol. The aqSOA from biomass burning contributes to the “brown” carbon (BrC) budget and exhibits light absorption wavelength dependence close to the upper bound of the values observed in laboratory experiments for fresh and processed biomass-burning emissions. We estimate that the aqSOA from residential wood combustion can account for up to 0.1-0.5 Tg of organic aerosol (OA) per y in Europe, equivalent to 4-20% of the total OA emissions. Our findings highlight the importance of aqSOA from anthropogenic emissions on air quality and climate.

  15. Direct observation of aqueous secondary organic aerosol from biomass-burning emissions

    PubMed Central

    Massoli, Paola; Paglione, Marco; Giulianelli, Lara; Carbone, Claudio; Rinaldi, Matteo; Decesari, Stefano; Sandrini, Silvia; Costabile, Francesca; Gobbi, Gian Paolo; Pietrogrande, Maria Chiara; Visentin, Marco; Scotto, Fabiana; Fuzzi, Sandro; Facchini, Maria Cristina

    2016-01-01

    The mechanisms leading to the formation of secondary organic aerosol (SOA) are an important subject of ongoing research for both air quality and climate. Recent laboratory experiments suggest that reactions taking place in the atmospheric liquid phase represent a potentially significant source of SOA mass. Here, we report direct ambient observations of SOA mass formation from processing of biomass-burning emissions in the aqueous phase. Aqueous SOA (aqSOA) formation is observed both in fog water and in wet aerosol. The aqSOA from biomass burning contributes to the “brown” carbon (BrC) budget and exhibits light absorption wavelength dependence close to the upper bound of the values observed in laboratory experiments for fresh and processed biomass-burning emissions. We estimate that the aqSOA from residential wood combustion can account for up to 0.1–0.5 Tg of organic aerosol (OA) per y in Europe, equivalent to 4–20% of the total OA emissions. Our findings highlight the importance of aqSOA from anthropogenic emissions on air quality and climate. PMID:27551086

  16. Characterising Brazilian biomass burning emissions using WRF-Chem with MOSAIC sectional aerosol

    NASA Astrophysics Data System (ADS)

    Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W. T.; Bela, M. M.; Pereira, G.; Trembath, J.; Kaiser, J. W.; Longo, K. M.; Freitas, S. R.; Coe, H.; McFiggans, G.

    2014-09-01

    The South American Biomass Burning Analysis (SAMBBA) field campaign took detailed in-situ flight measurements of aerosol during the 2012 dry season to characterise biomass burning aerosol and improve understanding of its impacts on weather and climate. Developments have been made to the Weather research and Forecast model with chemistry (WRF-Chem) model to improve the representation of biomass burning aerosol in the region by coupling a sectional aerosol scheme to the plume rise parameterisation. Brazilian Biomass Burning Emissions Model (3BEM) fire emissions are used, prepared using PREP-CHEM-SRC, and mapped to CBM-Z and MOSAIC species. Model results have been evaluated against remote sensing products, AERONET sites, and four case studies of flight measurements from the SAMBBA campaign. WRF-Chem predicted layers of elevated aerosol loadings (5-20 μg sm-3) of particulate organic matter at high altitude (6-8 km) over tropical forest regions, while flight measurements showed a sharp decrease above 2-4 km altitude. This difference was attributed to the plume-rise parameterisation overestimating injection height. The 3BEM emissions product was modified using estimates of active fire size and burned area for the 2012 fire season, which reduced the fire size. The enhancement factor for fire emissions was increased from 1.3 to 5 to retain reasonable aerosol optical depths (AOD). The smaller fire size lowered the injection height of the emissions, but WRF-Chem still showed elevated aerosol loadings between 4-5 km altitude. Over eastern Cerrado (savannah-like) regions, both modelled and measured aerosol loadings decreased above approximately 4 km altitude. Compared with MODIS satellite data and AERONET sites, WRF-Chem represented AOD magnitude well (between 0.3-1.5) over western tropical forest fire regions in the first half of the campaign, but tended to over-predict them in the second half, when precipitation was more significant. Over eastern Cerrado regions, WRF

  17. Characterising Brazilian biomass burning emissions using WRF-Chem with MOSAIC sectional aerosol

    NASA Astrophysics Data System (ADS)

    Archer-Nicholls, S.; Lowe, D.; Darbyshire, E.; Morgan, W. T.; Bela, M. M.; Pereira, G.; Trembath, J.; Kaiser, J. W.; Longo, K. M.; Freitas, S. R.; Coe, H.; McFiggans, G.

    2015-03-01

    The South American Biomass Burning Analysis (SAMBBA) field campaign took detailed in situ flight measurements of aerosol during the 2012 dry season to characterise biomass burning aerosol and improve understanding of its impacts on weather and climate. Developments have been made to the Weather Research and Forecast model with chemistry (WRF-Chem) model to improve the representation of biomass burning aerosol in the region, by coupling a sectional aerosol scheme to the plume-rise parameterisation. Brazilian Biomass Burning Emissions Model (3BEM) fire emissions are used, prepared using PREP-CHEM-SRC, and mapped to CBM-Z and MOSAIC species. Model results have been evaluated against remote sensing products, AERONET sites, and four case studies of flight measurements from the SAMBBA campaign. WRF-Chem predicted layers of elevated aerosol loadings (5-20 μg sm-3) of particulate organic matter at high altitude (6-8 km) over tropical forest regions, while flight measurements showed a sharp decrease above 2-4 km altitude. This difference was attributed to the plume-rise parameterisation overestimating injection height. The 3BEM emissions product was modified using estimates of active fire size and burned area for the 2012 fire season, which reduced the fire size. The enhancement factor for fire emissions was increased from 1.3 to 5 to retain reasonable aerosol optical depths (AODs). The smaller fire size lowered the injection height of the emissions, but WRF-Chem still showed elevated aerosol loadings between 4-5 km altitude. Over eastern cerrado (savannah-like) regions, both modelled and measured aerosol loadings decreased above approximately 4 km altitude. Compared with MODIS satellite data and AERONET sites, WRF-Chem represented AOD magnitude well (between 0.3-1.5) over western tropical forest fire regions in the first half of the campaign, but tended to over-predict them in the second half, when precipitation was more significant. Over eastern cerrado regions, WRF

  18. Modeling Trends in Tropospheric Aerosol Burden & Its Radiative Effects

    EPA Science Inventory

    Large changes in emissions of aerosol precursors have occurred across the southeast U.S., North America, as well as the northern hemisphere. The spatial heterogeneity and contrasting trends in the aerosol burden is resulting in differing effects on regional radiative balance. Mul...

  19. Comparison between simulated and observed chemical composition of fine aerosols in Paris (France) during springtime: contribution of regional versus continental emissions

    NASA Astrophysics Data System (ADS)

    Sciare, J.; D'Argouges, O.; Sarda-Estève, R.; Gaimoz, C.; Gros, V.; Zhang, Q. J.; Beekmann, M.; Sanchez, O.

    2010-07-01

    Hourly concentrations of inorganic salts (ions) and carbonaceous material in fine aerosols (aerodynamic diameter, A.D.<2.5 μm) have been determined experimentally from fast measurements performed for a 3-week period in spring 2007 in Paris (France). The sum of these two chemical components (ions and carbonaceous aerosols) has shown to account for most of the fine aerosol mass (PM2.5). This time-resolved dataset allowed investigating the factors controlling the levels of PM2.5 in Paris and showed that polluted periods with PM2.5<15 μg/m3 were characterized by air masses of continental (North-Western Europe) origin and chemical composition made by 75% of ions. By contrast, periods with clean marine air masses have shown the lowest PM2.5 concentrations (typically of about 10 μg/m3); carbonaceous aerosols contributing for most of this mass (typically 75%). In order to better discriminate between regional and continental contributions to the observed chemical composition and concentrations of PM2.5 over Paris, a comparative study was performed between this time-resolved dataset and the outputs of a chemistry transport model (CHIMERE), showing a relatively good capability of the model to reproduce the time-limited intense maxima observed in the field for PM2.5 and ion species. Different model scenarios were then investigated switching off regional and European (North-Western and Central) emissions. Results of these scenarios have clearly shown that most of the ions observed over Paris during polluted periods, were either transported or formed in-situ from gas precursors transported from Northern Europe. By opposite, long-range transport from Europe appeared to poorly contribute to the levels of carbonaceous aerosols observed over Paris. The model failed to properly account for the concentration levels and variability of secondary organic aerosols (SOA) determined experimentally by the EC-tracer method. The abundance of SOA (relatively to organic aerosol, OA) was as

  20. Comparison between simulated and observed chemical composition of fine aerosols in Paris (France) during springtime: contribution of regional versus continental emissions

    NASA Astrophysics Data System (ADS)

    Sciare, J.; D'Argouges, O.; Zhang, Q. J.; Sarda-Estève, R.; Gaimoz, C.; Gros, V.; Beekmann, M.; Sanchez, O.

    2010-12-01

    Hourly concentrations of inorganic salts (ions) and carbonaceous material in fine aerosols (aerodynamic diameter, A.D. <2.5 μm) have been determined experimentally from fast measurements performed for a 3-week period in spring 2007 in Paris (France). The sum of these two chemical components (ions and carbonaceous aerosols) has shown to account for most of the fine aerosol mass (PM2.5). This time-resolved dataset allowed investigating the factors controlling the levels of PM2.5 in Paris and showed that polluted periods with PM2.5 > 15 μg m-3 were characterized by air masses of continental (North-Western Europe) origin and chemical composition made by 75% of ions. By contrast, periods with clean marine air masses have shown the lowest PM2.5 concentrations (typically of about 10 μg m-3); carbonaceous aerosols contributing for most of this mass (typically 75%). In order to better discriminate between local and continental contributions to the observed chemical composition and concentrations of PM2.5 over Paris, a comparative study was performed between this time-resolved dataset and the outputs of a chemistry transport model (CHIMERE), showing a relatively good capability of the model to reproduce the time-limited intense maxima observed in the field for PM2.5 and ion species. Different model scenarios were then investigated switching off local and European (North-Western and Central) emissions. Results of these scenarios have clearly shown that most of the ions observed over Paris during polluted periods, were either transported or formed in-situ from gas precursors transported from Northern Europe. On the opposite, long-range transport from Europe appeared to weakly contribute to the levels of carbonaceous aerosols observed over Paris. The model failed to properly account for the concentration levels and variability of secondary organic aerosols (SOA) determined experimentally by the EC-tracer method. The abundance of SOA (relatively to organic aerosol, OA) was as

  1. Global top-down smoke aerosol emissions estimation using satellite fire radiative power measurements

    NASA Astrophysics Data System (ADS)

    Ichoku, C.; Ellison, L.

    2013-10-01

    Biomass burning occurs seasonally in most vegetated parts of the world, consuming large amounts of biomass fuel, generating intense heat energy, and emitting corresponding amounts of smoke plumes that comprise different species of aerosols and trace gases. Accurate estimates of these emissions are required as model inputs to evaluate and forecast smoke plume transport and impacts on air quality, human health, clouds, weather, radiation, and climate. Emissions estimates have long been based on bottom-up approaches that are not only complex, but also fraught with compounding uncertainties. Fortunately, a series of recent studies have revealed that both the rate of biomass consumption and the rate of emission of aerosol particulate matter (PM) by open biomass burning are directly proportional to the rate of release of fire radiative energy (FRE), which is fire radiative power (FRP) that is measurable from satellite. This direct relationship enables the determination of coefficients of emission (Ce), which can be used to convert FRP or FRE to smoke aerosol emissions in the same manner as emission factors (EFs) are used to convert burned biomass to emissions. We have leveraged this relationship to generate the first global 1° × 1° gridded Ce product for smoke aerosol or total particulate matter (TPM) emissions using coincident measurements of FRP and aerosol optical thickness (AOT) from the Moderate-resolution Imaging Spectro-radiometer (MODIS) sensors aboard the Terra and Aqua satellites. This new Fire Energetics and Emissions Research version 1.0 (FEER.v1) Ce product has now been released to the community and can be obtained from http://feer.gsfc.nasa.gov/, along with the corresponding 1-to-1 mapping of their quality assurance (QA) flags that will enable the Ce values to be filtered by quality for use in various applications. The regional averages of Ce values for different ecosystem types were found to be in

  2. Aerosol emissions and dimming/brightening in Europe: Sensitivity studies with ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Folini, D.; Wild, M.

    2011-11-01

    Observational data indicate a decrease of surface solar radiation (SSR) in Europe from about 1950 to the mid-1980s, followed by a renewed increase. Changing aerosol emissions have been suggested as a likely cause for this observed dimming and brightening. To quantify this hypothesis, we performed ensembles of transient sensitivity experiments with the global climate model ECHAM5-HAM, which includes interactive treatment of aerosols. The simulations cover the period 1950-2005 and use transient aerosol emissions (National Institute of Environmental Science, Japan) and prescribed sea surface temperatures (SSTs) from the Hadley Centre. The simulated clear-sky dimming and brightening can be attributed to changing aerosol emissions from fossil fuel combustion. Ensemble means of modeled SSR trends are in agreement with observed values. Dimming ceases too early in the model, around 1970. Potential causes are discussed. Brightening sets in at about the right time. Regional differences of modeled SSR are substantial, with clear-sky dimming trends ranging from -6.1 (eastern Europe) to -0.4 W m-2 decade-1 (British Isles) and brightening trends ranging from +1.3 to +6.3 W m-2 decade-1 (Scandinavia and eastern Europe). All-sky conditions show similar trends in the ensemble mean, but the spread among ensemble members is considerable, emphasizing the importance of clouds. Surface temperatures are found to depend mostly on the prescribed SSTs, with an additional aerosol component in some regions like eastern Europe. For precipitation, internal variability is too large to allow for any firm conclusions.

  3. The Influence of Ozone Precursor Emissions from Four World Regions on Tropospheric Composition and Radiative Climate Forcing

    NASA Technical Reports Server (NTRS)

    Fry, Meridith; Naik, Vaishali; West, J. Jason; Schwarzkopf, M. Daniel; Fiore, Arlene M.; Collins, William J.; Dentener, Frank J.; Shindell, Drew T.; Atherton, Cyndi; Bergmann, Daniel; Duncan, Bryan N.; Hess, Peter; MacKenzie, Ian A.; Marmer, Elina; Schultz, Martin G.; Szopa, Sophie; Wild, Oliver; Zeng, Guang

    2012-01-01

    Ozone (O3) precursor emissions influence regional and global climate and air quality through changes in tropospheric O3 and oxidants, which also influence methane (CH4) and sulfate aerosols (SO4 (sup 2-)). We examine changes in the tropospheric composition of O3, CH4, SO4 (sup 2-) and global net radiative forcing (RF) for 20% reductions in global CH4 burden and in anthropogenic O3 precursor emissions (NOx, NMVOC, and CO) from four regions (East Asia, Europe and Northern Africa, North America, and South Asia) using the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) simulations, assessing uncertainty (mean plus or minus 1 standard deviation) across multiple CTMs. We evaluate steady state O3 responses, including long-term feedbacks via CH4. With a radiative transfer model that includes greenhouse gases and the aerosol direct effect, we find that regional NOx reductions produce global, annually averaged positive net RFs (0.2 plus or minus 0.6 to 1.7 2 mWm(sup -2)/Tg N yr(sup -1), with some variation among models. Negative net RFs result from reductions in global CH4 (-162.6 plus or minus 2 mWm(sup -2) for a change from 1760 to 1408 ppbv CH4) and regional NMVOC (-0.4 plus or minus 0.2 to 0.7 plus or minus 0.2 mWm(sup -2)/Tg C yr(sup -1) and CO emissions (-0.13 plus or minus 0.02 to -0.15 plus or minus 0.02 mWm(sup-2)/Tg CO yr(sup-1). Including the effect of O3 on CO2 uptake by vegetation likely makes these net RFs more negative by -1.9 to- 5.2 mWm(sup -2)/Tg N yr(sup -1), -0.2 to -0.7 mWm(sup -2)/Tg C yr(sup -1), and -0.02 to -0.05 mWm(sup -2)/ Tg CO yr(sup -1). Net RF impacts reflect the distribution of concentration changes, where RF is affected locally by changes in SO4 (sup -2), regionally to hemispherically by O3, and globally by CH4. Global annual average SO4 2 responses to oxidant changes range from 0.4 plus or minus 2.6 to -1.9 plus or minus 1.3 Gg for NOx reductions, 0.1 plus or minus 1.2 to -0.9 plus

  4. Indoor terpene emissions from cooking with herbs and pepper and their secondary organic aerosol production potential.

    PubMed

    Klein, Felix; Farren, Naomi J; Bozzetti, Carlo; Daellenbach, Kaspar R; Kilic, Dogushan; Kumar, Nivedita K; Pieber, Simone M; Slowik, Jay G; Tuthill, Rosemary N; Hamilton, Jacqueline F; Baltensperger, Urs; Prévôt, André S H; El Haddad, Imad

    2016-11-10

    Cooking is widely recognized as an important source of indoor and outdoor particle and volatile organic compound emissions with potential deleterious effects on human health. Nevertheless, cooking emissions remain poorly characterized. Here the effect of herbs and pepper on cooking emissions was investigated for the first time to the best of our knowledge using state of the art mass spectrometric analysis of particle and gas-phase composition. Further, the secondary organic aerosol production potential of the gas-phase emissions was determined by smog chamber aging experiments. The emissions of frying meat with herbs and pepper include large amounts of mono-, sesqui- and diterpenes as well as various terpenoids and p-cymene. The average total terpene emission rate from the use of herbs and pepper during cooking is estimated to be 46 ± 5 gg(-1)Herbs min(-1). These compounds are highly reactive in the atmosphere and lead to significant amounts of secondary organic aerosol upon aging. In summary we demonstrate that cooking with condiments can constitute an important yet overlooked source of terpenes in indoor air.

  5. Indoor terpene emissions from cooking with herbs and pepper and their secondary organic aerosol production potential

    NASA Astrophysics Data System (ADS)

    Klein, Felix; Farren, Naomi J.; Bozzetti, Carlo; Daellenbach, Kaspar R.; Kilic, Dogushan; Kumar, Nivedita K.; Pieber, Simone M.; Slowik, Jay G.; Tuthill, Rosemary N.; Hamilton, Jacqueline F.; Baltensperger, Urs; Prévôt, André S. H.; El Haddad, Imad

    2016-11-01

    Cooking is widely recognized as an important source of indoor and outdoor particle and volatile organic compound emissions with potential deleterious effects on human health. Nevertheless, cooking emissions remain poorly characterized. Here the effect of herbs and pepper on cooking emissions was investigated for the first time to the best of our knowledge using state of the art mass spectrometric analysis of particle and gas-phase composition. Further, the secondary organic aerosol production potential of the gas-phase emissions was determined by smog chamber aging experiments. The emissions of frying meat with herbs and pepper include large amounts of mono-, sesqui- and diterpenes as well as various terpenoids and p-cymene. The average total terpene emission rate from the use of herbs and pepper during cooking is estimated to be 46 ± 5 gg-1Herbs min-1. These compounds are highly reactive in the atmosphere and lead to significant amounts of secondary organic aerosol upon aging. In summary we demonstrate that cooking with condiments can constitute an important yet overlooked source of terpenes in indoor air.

  6. Indoor terpene emissions from cooking with herbs and pepper and their secondary organic aerosol production potential

    PubMed Central

    Klein, Felix; Farren, Naomi J.; Bozzetti, Carlo; Daellenbach, Kaspar R.; Kilic, Dogushan; Kumar, Nivedita K.; Pieber, Simone M.; Slowik, Jay G.; Tuthill, Rosemary N.; Hamilton, Jacqueline F.; Baltensperger, Urs; Prévôt, André S. H.; El Haddad, Imad

    2016-01-01

    Cooking is widely recognized as an important source of indoor and outdoor particle and volatile organic compound emissions with potential deleterious effects on human health. Nevertheless, cooking emissions remain poorly characterized. Here the effect of herbs and pepper on cooking emissions was investigated for the first time to the best of our knowledge using state of the art mass spectrometric analysis of particle and gas-phase composition. Further, the secondary organic aerosol production potential of the gas-phase emissions was determined by smog chamber aging experiments. The emissions of frying meat with herbs and pepper include large amounts of mono-, sesqui- and diterpenes as well as various terpenoids and p-cymene. The average total terpene emission rate from the use of herbs and pepper during cooking is estimated to be 46 ± 5 gg-1Herbs min-1. These compounds are highly reactive in the atmosphere and lead to significant amounts of secondary organic aerosol upon aging. In summary we demonstrate that cooking with condiments can constitute an important yet overlooked source of terpenes in indoor air. PMID:27830718

  7. Emissions and Characteristics of Ice Nucleating Particles Associated with Laboratory Generated Nascent Sea Spray Aerosol

    NASA Astrophysics Data System (ADS)

    McCluskey, C. S.; Hill, T. C. J.; Beall, C.; Sultana, C. M.; Moore, K.; Cornwell, G.; Lee, C.; Al-Mashat, H.; Laskina, O.; Trueblood, J.; Grassian, V. H.; Prather, K. A.; Kreidenweis, S. M.; DeMott, P. J.

    2015-12-01

    Accurate emission rates and activity spectra of atmospheric ice nucleating particles (INPs) are required for proper representation of aerosol-cloud interactions in atmospheric modeling studies. However, few investigations have quantified or characterized oceanic INP emissions. In conjunction with the Center for Aerosol Impacts on the Climate and the Environment, we have directly measured changes in INP emissions and properties of INPs from nascent sea spray aerosol (SSA) through the evolution of phytoplankton blooms. Multiple offline and online instruments were used to monitor aerosol chemistry and size, and bulk water characteristics during two phytoplankton bloom experiments. Two methods were utilized to monitor the number concentrations of INPs from 0 to -34 °C: The online CSU continuous flow diffusion chamber (CFDC) and collections processed offline using the CSU ice spectrometer. Single particle analyses were performed on ice crystal residuals downstream of the CFDC, presumed to be INPs, via scanning transmission electron microscopy (STEM) and Raman microspectroscopy. Preliminary results indicate that laboratory-generated nascent SSA corresponds to number concentrations of INPs that are generally consistent with open ocean regions, based on current knowledge. STEM analyses revealed that the sizes of ice crystal residuals that were associated with nascent SSA ranged from 0.3 to 2.5 μm. Raman microspectroscopy analysis of 1 μm sized residuals found a variety of INP identities, including long chain organics, diatom fragments and polysaccharides. Our data suggest that biological processes play a significant role in ocean INP emissions by generating the species and compounds that were identified during these studies.

  8. A new approach to modeling aerosol effects on East Asian climate: Parametric uncertainties associated with emissions, cloud microphysics, and their interactions: AEROSOL EFFECTS ON EAST ASIAN CLIMATE

    SciTech Connect

    Yan, Huiping; Qian, Yun; Zhao, Chun; Wang, Hailong; Wang, Minghuai; Yang, Ben; Liu, Xiaohong; Fu, Qiang

    2015-09-09

    In this study, we adopt a parametric sensitivity analysis framework that integrates the quasi-Monte Carlo parameter sampling approach and a surrogate model to examine aerosol effects on the East Asian Monsoon climate simulated in the Community Atmosphere Model (CAM5). A total number of 256 CAM5 simulations are conducted to quantify the model responses to the uncertain parameters associated with cloud microphysics parameterizations and aerosol (e.g., sulfate, black carbon (BC), and dust) emission factors and their interactions. Results show that the interaction terms among parameters are important for quantifying the sensitivity of fields of interest, especially precipitation, to the parameters. The relative importance of cloud-microphysics parameters and emission factors (strength) depends on evaluation metrics or the model fields we focused on, and the presence of uncertainty in cloud microphysics imposes an additional challenge in quantifying the impact of aerosols on cloud and climate. Due to their different optical and microphysical properties and spatial distributions, sulfate, BC, and dust aerosols have very different impacts on East Asian Monsoon through aerosol-cloud-radiation interactions. The climatic effects of aerosol do not always have a monotonic response to the change of emission factors. The spatial patterns of both sign and magnitude of aerosol-induced changes in radiative fluxes, cloud, and precipitation could be different, depending on the aerosol types, when parameters are sampled in different ranges of values. We also identify the different cloud microphysical parameters that show the most significant impact on climatic effect induced by sulfate, BC and dust, respectively, in East Asia.

  9. Updating Sea Spray Aerosol Emissions in the Community Multiscale Air Quality Model

    NASA Astrophysics Data System (ADS)

    Gantt, B.; Bash, J. O.; Kelly, J.

    2014-12-01

    Sea spray aerosols (SSA) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. In this study, the Community Multiscale Air Quality (CMAQ) model is updated to enhance fine mode SSA emissions, include sea surface temperature (SST) dependency, and revise surf zone emissions. Based on evaluation with several regional and national observational datasets in the continental U.S., the updated emissions generally improve surface concentrations predictions of primary aerosols composed of sea-salt and secondary aerosols affected by sea-salt chemistry in coastal and near-coastal sites. Specifically, the updated emissions lead to better predictions of the magnitude and coastal-to-inland gradient of sodium, chloride, and nitrate concentrations at Bay Regional Atmospheric Chemistry Experiment (BRACE) sites near Tampa, FL. Including SST-dependency to the SSA emission parameterization leads to increased sodium concentrations in the southeast U.S. and decreased concentrations along the Pacific coast and northeastern U.S., bringing predictions into closer agreement with observations at most Interagency Monitoring of Protected Visual Environments (IMPROVE) and Chemical Speciation Network (CSN) sites. Model comparison with California Research at the Nexus of Air Quality and Climate Change (CalNex) observations will also be discussed, with particular focus on the South Coast Air Basin where clean marine air mixes with anthropogenic pollution in a complex environment. These SSA emission updates enable more realistic simulation of chemical processes in coastal environments, both in clean marine air masses and mixtures of clean marine and polluted conditions.

  10. A Multimodel Assessment of the Influence of Regional Anthropogenic Emission Reductions on Aerosol Direct Radiative Forcing and the Role of Intercontinental Transport

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Chin, Mian; West, Jason; Atherton, Cynthia S.; Bellouin, Nicolas; Bergmann, Dan; Bey, Isabelle; Bian, Huisheng; Diehl, Thomas; Forberth, Gerd; Hess, Peter; Schulz, Michael; Shindell, Drew; Takemura, Toshihiko; Tan, Qian

    2013-01-01

    In this study, we assess changes of aerosol optical depth (AOD) and direct radiative forcing (DRF) in response to the reduction of anthropogenic emissions in four major pollution regions in the Northern Hemisphere by using results from nine global models in the framework of the Hemispheric Transport of Air Pollution (HTAP). DRF at top of atmosphere (TOA) and surface is estimated based on AOD results from the HTAP models and AOD-normalized DRF (NDRF) from a chemical transport model. The multimodel results show that, on average, a 20% reduction of anthropogenic emissions in North America, Europe, East Asia, and South Asia lowers the global mean AOD (all-sky TOA DRF) by 9.2% (9.0%), 3.5% (3.0%), and 9.4% (10.0%) for sulfate, particulate organic matter (POM), and black carbon (BC), respectively. Global annual average TOA all-sky forcing efficiency relative to particle or gaseous precursor emissions from the four regions (expressed as multimodel mean +/- one standard deviation) is -3.5 +/-0.8, -4.0 +/- 1.7, and 29.5+/-18.1mW / sq m per Tg for sulfate (relative to SO2), POM, and BC, respectively. The impacts of the regional emission reductions on AOD and DRF extend well beyond the source regions because of intercontinental transport (ICT). On an annual basis, ICT accounts for 11 +/- 5% to 31 +/- 9% of AOD and DRF in a receptor region at continental or subcontinental scale, with domestic emissions accounting for the remainder, depending on regions and species. For sulfate AOD, the largest ICT contribution of 31 +/- 9% occurs in South Asia, which is dominated by the emissions from Europe. For BC AOD, the largest ICT contribution of 28 +/- 18% occurs in North America, which is dominated by the emissions from East Asia. The large spreads among models highlight the need to improve aerosol processes in models, and evaluate and constrain models with observations.

  11. Temperature and burning history affect emissions of greenhouse gases and aerosol particles from tropical peatland fire

    NASA Astrophysics Data System (ADS)

    Kuwata, Mikinori; Kai, Fuu Ming; Yang, Liudongqing; Itoh, Masayuki; Gunawan, Haris; Harvey, Charles F.

    2017-01-01

    Tropical peatland burning in Asia has been intensifying over the last decades, emitting huge amounts of gas species and aerosol particles. Both laboratory and field studies have been conducted to investigate emission from peat burning, yet a significant variability in data still exists. We conducted a series of experiments to characterize the gas and particulate matter emitted during burning of a peat sample from Sumatra in Indonesia. Heating temperature of peat was found to regulate the ratio of CH4 to CO2 in emissions (ΔCH4/ΔCO2) as well as the chemical composition of particulate matter. The ΔCH4/ΔCO2 ratio was larger for higher temperatures, meaning that CH4 emission is more pronounced at these conditions. Mass spectrometric analysis of organic components indicated that aerosol particles emitted at higher temperatures had more unsaturated bonds and ring structures than that emitted from cooler fires. The result was consistently confirmed by nuclear magnetic resonance analysis. In addition, CH4 emitted by burning charcoal, which is derived from previously burned peat, was lower by at least an order of magnitude than that from fresh peat. These results highlight the importance of both fire history and heating temperature for the composition of tropical peat-fire emissions. They suggest that remote sensing technologies that map fire histories and temperatures could provide improved estimates of emissions.

  12. Use of floating balls for reducing bacterial aerosol emissions from aeration in wastewater treatment processes.

    PubMed

    Hung, Hsueh Fen; Kuo, Yu Mei; Chien, Chih Ching; Chen, Chih Chieh

    2010-03-15

    The microorganism emissions from aeration in the wastewater treatment process may adversely affect air quality and human health. To control the liquid-to-air transport of microorganisms, commercially available balls were used and their control efficiencies were evaluated by a lab-scale aeration system. Escherichia coli as the test agent were aerosolized by the aeration system and size-fractionated E. coli-containing aerosol samples were collected by using an Andersen six-stage impactor with eosin methylene blue agar for subsequent culturing and enumeration of colonies. Aerosol samples were obtained without any control measure and with balls of four diameters (1.9, 2.9, 3.4 and 4.8 cm) in one, three and five layers covering the bubbling liquid surface. Experimental results showed that the control efficiencies of balls on bacterial aerosols varied from over 50% to nearly 100% under various control settings and substantially increased as the ball size decreased and the number of applied layers increased.

  13. Investigation of aviation emission impacts on global tropospheric chemistry and climate using a size-resolved aerosol-chemistry model

    NASA Astrophysics Data System (ADS)

    Kapadia, Zarashpe; Spracklen, Dominick; Arnold, Stephen; Borman, Duncan; Mann, Graham; Pringle, Kirsty; Monks, Sarah; Reddington, Carly; Rap, Alexandru; Scott, Catherine

    2014-05-01

    Aviation is responsible for 3% of global anthropogenic CO2 emissions, but 2-14% of anthropogenic induced climate warming due to contributions from short lived climate forcers. The global civil aviation fleet is projected to double by 2026 in relation to a 2006 baseline and so will play a substantial role in future climate change. Uncertainty in the net impact of aviation on climate is largely due to uncertainty in the impacts of aviation emissions on ozone and aerosol. To study the impact of aviation emissions we use the GLOMAP-mode global aerosol microphysics model coupled to the 3-D chemical transport model TOMCAT. GLOMAP-mode has been extended to include treatment of nitrate aerosol. We include a full suite of non-CO2 aviation emissions (including NOX, SO2, HCs, BC and OC) in the model. We combined the simulated changes in ozone and aerosol with a 3D radiative transfer model to quantify the radiative effect due to aviation non-CO2 emissions. We find that aviation emissions increase O3 concentrations by up to 5.3% in the upper troposphere (UT), broadly matching previous studies. Black carbon (BC) and organic carbon (OC) concentrations increase by 26.5% and 14.6% respectively in the UT, whereas nitrate aerosol is reduced in some regions due to co-emission of NOX and SO2 In the UT, aviation emissions increase both total aerosol number as well as the concentration of particles greater than 70 nm diameter (N70). Entrainment of these particles into the free troposphere results in aviation emissions also increasing N70 in the boundary layer, causing a cooling through the first aerosol indirect effect. We explore differences in these responses compared with those simulated when using the recommended aviation emissions from CMIP5 (5th Climate Model Intercomparison Project), which only include NOX and BC emissions. Our results suggest that aviation emissions of SO2 and HCs neglected by CMIP5 produce important effects on ozone, aerosol number, and N70. We suggest CMIP5

  14. Final Report, The Influence of Organic-Aerosol Emissions and Aging on Regional and Global Aerosol Size Distributions and the CCN Number Budget

    SciTech Connect

    Donahue, Neil M.

    2015-12-23

    We conducted laboratory experiments and analyzed data on aging of organic aerosol and analysis of field data on volatility and CCN activity. With supplemental ASR funding we participated in the FLAME-IV campaign in Missoula MT in the Fall of 2012, deploying a two-chamber photochemical aging system to enable experimental exploration of photochemical aging of biomass burning emissions. Results from that campaign will lead to numerous publications, including demonstration of photochemical production of Brown Carbon (BrC) from secondary organic aerosol associated with biomass burning emissions as well as extensive characterization of the effect of photochemical aging on the overall concentrations of biomass burning organic aerosol. Excluding publications arising from the FLAME-IV campaign, project research resulted in 8 papers: [11, 5, 3, 10, 12, 4, 8, 7], including on in Nature Geoscience addressing the role of organic compounds in nanoparticle growth [11

  15. Arabian Sea tropical cyclones intensified by emissions of black carbon and other aerosols.

    PubMed

    Evan, Amato T; Kossin, James P; Chung, Chul Eddy; Ramanathan, V

    2011-11-02

    Throughout the year, average sea surface temperatures in the Arabian Sea are warm enough to support the development of tropical cyclones, but the atmospheric monsoon circulation and associated strong vertical wind shear limits cyclone development and intensification, only permitting a pre-monsoon and post-monsoon period for cyclogenesis. Thus a recent increase in the intensity of tropical cyclones over the northern Indian Ocean is thought to be related to the weakening of the climatological vertical wind shear. At the same time, anthropogenic emissions of aerosols have increased sixfold since the 1930s, leading to a weakening of the southwesterly lower-level and easterly upper-level winds that define the monsoonal circulation over the Arabian Sea. In principle, this aerosol-driven circulation modification could affect tropical cyclone intensity over the Arabian Sea, but so far no such linkage has been shown. Here we report an increase in the intensity of pre-monsoon Arabian Sea tropical cyclones during the period 1979-2010, and show that this change in storm strength is a consequence of a simultaneous upward trend in anthropogenic black carbon and sulphate emissions. We use a combination of observational, reanalysis and model data to demonstrate that the anomalous circulation, which is radiatively forced by these anthropogenic aerosols, reduces the basin-wide vertical wind shear, creating an environment more favourable for tropical cyclone intensification. Because most Arabian Sea tropical cyclones make landfall, our results suggest an additional impact on human health from regional air pollution.

  16. Particle-Induced X-Ray Emission Analysis of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Gleason, Colin; Harrington, Charles; Schuff, Katie; Battaglia, Maria; Moore, Robert; Turley, Colin; Vineyard, Michael; Labrake, Scott

    2010-11-01

    We are developing a research program in ion-beam analysis (IBA) of atmospheric aerosols at the Union College Ion-Beam Analysis Laboratory to study the transport, transformation, and effects of airborne pollution in Upstate New York. The simultaneous applications of the IBA techniques of particle-induced X-ray emission (PIXE), Rutherford back-scattering spectrometry (RBS), particle-induced gamma-ray emission (PIGE), and proton elastic scattering analysis (PESA) is a powerful tool for the study of airborne pollution because they are non-destructive and provide quantitative information on nearly all elements of the periodic table. PIXE is the main IBA technique because it is able to detect nearly all elements from Na to U with high sensitivities and low detection limits. The aerosol samples are collected with cascade impactors that allow for the study of particulate matter as a function of particle size and the samples are analyzed using proton beams with energies around 2 MeV from the Union College 1.1-MV Pelletron Accelerator. The emitted X-rays are measured using a silicon drift detector with a resolution of 136 eV. We will describe how the aerosol samples were collected, discuss the PIXE analysis, and present preliminary results.

  17. Excitation-emission spectra and fluorescence quantum yields for fresh and aged biogenic secondary organic aerosols

    SciTech Connect

    Lee, Hyun Ji; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A.

    2013-05-10

    Certain biogenic secondary organic aerosols (SOA) become absorbent and fluorescent when exposed to reduced nitrogen compounds such as ammonia, amines and their salts. Fluorescent SOA may potentially be mistaken for biological particles by detection methods relying on fluorescence. This work quantifies the spectral distribution and effective quantum yields of fluorescence of SOA generated from two monoterpenes, limonene and a-pinene, and two different oxidants, ozone (O3) and hydroxyl radical (OH). The SOA was generated in a smog chamber, collected on substrates, and aged by exposure to ~100 ppb ammonia vapor in air saturated with water vapor. Absorption and excitation-emission matrix (EEM) spectra of aqueous extracts of aged and control SOA samples were measured, and the effective absorption coefficients and fluorescence quantum yields (~0.005 for 349 nm excitation) were determined from the data. The strongest fluorescence for the limonene-derived SOA was observed for excitation = 420+- 50 nm and emission = 475 +- 38 nm. The window of the strongest fluorescence shifted to excitation = 320 +- 25 nm and emission = 425 +- 38 nm for the a-pinene-derived SOA. Both regions overlap with the excitation-emission matrix (EEM) spectra of some of the fluorophores found in primary biological aerosols. Our study suggests that, despite the low quantum yield, the aged SOA particles should have sufficient fluorescence intensities to interfere with the fluorescence detection of common bioaerosols.

  18. Will Aerosol Hygroscopicity Change with Biodiesel, Renewable Diesel Fuels and Emission Control Technologies?

    PubMed

    Vu, Diep; Short, Daniel; Karavalakis, Georgios; Durbin, Thomas D; Asa-Awuku, Akua

    2017-02-07

    The use of biodiesel and renewable diesel fuels in compression ignition engines and aftertreatment technologies may affect vehicle exhaust emissions. In this study two 2012 light-duty vehicles equipped with direct injection diesel engines, diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) were tested on a chassis dynamometer. One vehicle was tested over the Federal Test Procedure (FTP) cycle on seven biodiesel and renewable diesel fuel blends. Both vehicles were exercised over double Environmental Protection Agency (EPA) Highway fuel economy test (HWFET) cycles on ultralow sulfur diesel (ULSD) and a soy-based biodiesel blend to investigate the aerosol hygroscopicity during the regeneration of the DPF. Overall, the apparent hygroscopicity of emissions during nonregeneration events is consistently low (κ < 0.1) for all fuels over the FTP cycle. Aerosol emitted during filter regeneration is significantly more CCN active and hygroscopic; average κ values range from 0.242 to 0.439 and are as high as 0.843. Regardless of fuel, the current classification of "fresh" tailpipe emissions as nonhygroscopic remains true during nonregeneration operation. However, aftertreatment technologies such as DPF, will produce significantly more hygroscopic particles during regeneration. To our knowledge, this is the first study to show a significant enhancement of hygroscopic materials emitted during DPF regeneration of on-road diesel vehicles. As such, the contribution of regeneration emissions from a growing fleet of diesel vehicles will be important.

  19. Combined trajectory clustering and aerosol fields analysis to evaluate the potential emission flux to aerosol pollutants in an urban and semi-urban atmospheres in eastern India

    NASA Astrophysics Data System (ADS)

    Kumar, B. D.; Verma, S.

    2015-12-01

    A hybrid source-receptor analysis was carried out to evaluate the potential emission flux to winter monsoon (WinMon) aerosols over eastern India urban (Kolkata, Kol) and semi-urban atmospheres (Kharagpur, Kgp). This was done through application of fuzzy c-mean clustering to back-trajectory data combined with emission flux and residence time weighted aerosols analysis. WinMon mean aerosol optical depth (AOD) and angstrom exponent (AE) at Kol were respectively slightly higher than and nearly equal to that at Kgp. Out of six source region clusters over Indian subcontinent and two over Indian oceanic region, the cluster mean AOD was the highest when associated with the mean path of air mass originating from the Bay of Bengal (BoB) and the Arabian sea (AS) clusters at Kol and that from the Indo-Gangetic plain (IGP)cluster at Kgp. Spatial distribution of weighted AOD fields showed the highest potential source of aerosols over the IGP, majorly over upper IGP (IGP-U), lower IGP (IGP-L) and eastern region (ER) clusters. The emission flux contribution potential (EFCP) of fossil fuel (FF) emissions at surface (SL) of Kol/Kgp , elevated layer (EL) of Kol, and of biomass burning (BB) emissions at SL of Kol were majorly from IGP-U, IGP-L and IGP-U/L clusters respectively. The EFCP of FF/BB emissions at Kgp-EL/SL, and that of BB at EL of Kol/Kgp were mainly from ER and Africa (AFR) clusters respectively. Though the AFR cluster was constituted of significantly high emission flux source potential of dust emissions, the EFCP of dust from NWI was comparable to that from AFR at Kol SL/EL.

  20. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India, 1996-2010

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Zhang, Q.; Streets, D. G.

    2011-09-01

    China and India are the two largest anthropogenic aerosol generating countries in the world. In this study, we develop a new inventory of sulfur dioxide (SO2) and primary carbonaceous aerosol (i.e., black and organic carbon, BC and OC) emissions from these two countries for the period 1996-2010, using a technology-based methodology. Emissions from major anthropogenic sources and open biomass burning are included, and time-dependent trends in activity rates and emission factors are incorporated in the calculation. Year-specific monthly temporal distributions for major sectors and gridded emissions at a resolution of 0.1°×0.1° distributed by multiple year-by-year spatial proxies are also developed. In China, the interaction between economic development and environmental protection causes large temporal variations in the emission trends. From 1996 to 2000, emissions of all three species showed a decreasing trend (by 9 %-17 %) due to a slowdown in economic growth, a decline in coal use in non-power sectors, and the implementation of air pollution control measures. With the economic boom after 2000, emissions from China changed dramatically. BC and OC emissions increased by 46 % and 33 % to 1.85 Tg and 4.03 Tg in 2010. SO2 emissions first increased by 61 % to 34.0 Tg in 2006, and then decreased by 9.2 % to 30.8 Tg in 2010 due to the wide application of flue-gas desulfurization (FGD) equipment in power plants. Driven by the remarkable energy consumption growth and relatively lax emission controls, emissions from India increased by 70 %, 41 %, and 35 % to 8.81 Tg, 1.02 Tg, and 2.74 Tg in 2010 for SO2, BC, and OC, respectively. Monte Carlo simulations are used to quantify the emission uncertainties. The average 95 % confidence intervals (CIs) of SO2, BC, and OC emissions are estimated to be -16 %-17 %, -43 %-93 %, and -43 %-80 % for China, and -15 %-16 %, -41 %-87 %, and -44 %-92 % for India, respectively. Sulfur content, fuel use, and sulfur retention of hard coal and

  1. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India, 1996-2010

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Streets, D. G.

    2011-07-01

    China and India are the two largest anthropogenic aerosol generating countries in the world. In this study, we develop a new inventory of sulfur dioxide (SO2) and primary carbonaceous aerosol (i.e., black and organic carbon, BC and OC) emissions from these two countries for the period 1996-2010, using a technology-based methodology. Emissions from major anthropogenic sources and open biomass burning are included, and time-dependent trends in activity rates and emission factors are incorporated in the calculation. Year-specific monthly fractions for major sectors and gridded emissions at a resolution of 0.1° × 0.1° distributed by multiple year-by-year spatial proxies are also developed. In China, the interaction between economic development and environmental protection causes large temporal variations in the emission trends. From 1996 to 2000, emissions of all three species showed a decreasing trend (by 9 %-17 %) due to a slowdown in economic growth, a decline in coal use in non-power sectors, and the implementation of air pollution control measures. With the economic boom after 2000, emissions from China changed dramatically. BC and OC emissions increased by 46 % and 33 % to 1.85 Tg and 4.03 Tg in 2010. SO2 emissions first increased by 61 % to 34.0 Tg in 2006, and then decreased by 9.2 % to 30.8 Tg in 2010 due to the wide application of flue-gas desulfurization (FGD) equipment in power plants. Driven by the remarkable energy consumption growth and relatively lax emission controls, emissions from India increased by 70 %, 41 %, and 35 % to 8.81 Tg, 1.02 Tg, and 2.74 Tg in 2010 for SO2, BC, and OC, respectively. Monte Carlo simulations are used to quantify the emission uncertainties. The average 95 % confidence intervals (CIs) of SO2, BC, and OC emissions are estimated to be -16 %-17 %, -43 %-93 %, and -43 %-80 % for China, and -15 %-16 %, -41 %-87 %, and -44 %-92 % for India, respectively. Sulfur content, fuel use, and sulfur retention of hard coal and the actual

  2. Radiative forcing and climate metrics for ozone precursor emissions: the impact of multi-model averaging

    NASA Astrophysics Data System (ADS)

    MacIntosh, C. R.; Shine, K. P.; Collins, W. J.

    2014-10-01

    Multi-model ensembles are frequently used to assess understanding of the response of ozone and methane lifetime to changes in emissions of ozone precursors such as NOx, VOC and CO. When these ozone changes are used to calculate radiative forcing (RF) (and climate metrics such as the global warming potential (GWP) and global temperature potential (GTP)) there is a methodological choice, determined partly by the available computing resources, as to whether the mean ozone (and methane lifetime) changes are input to the radiation code, or whether each model's ozone and methane changes are used as input, with the average RF computed from the individual model RFs. We use data from the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model ensemble to assess the impact of this choice for emission changes in 4 regions (East Asia, Europe, North America and South Asia). We conclude that using the multi-model mean ozone and methane responses is accurate for calculating the mean RF, with differences up to 0.6% for CO, 0.7% for VOC and 2% for NOx. Differences of up to 60% for NOx 7% for VOC and 3% for CO are introduced into the 20 year GWP as a result of the exponential decay terms, with similar values for the 20 years GTP. However, estimates of the SD calculated from the ensemble-mean input fields (where the SD at each point on the model grid is added to or subtracted from the mean field) are almost always substantially larger in RF, GWP and GTP metrics than the true SD, and can be larger than the model range for short-lived ozone RF, and for the 20 and 100 year GWP and 100 year GTP. We find that the effect is generally most marked for the case of NOx emissions, where the net effect is a smaller residual of terms of opposing signs. For example, the SD for the 20 year GWP is two to three times larger using the ensemble-mean fields than using the individual models to calculate the RF. Hence, while the average of multi-model fields

  3. Time evolution and emission factors of aerosol particles from day and night time savannah fires

    NASA Astrophysics Data System (ADS)

    Vakkari, Ville; Beukes, Johan Paul; Tiitta, Petri; Venter, Andrew; Jaars, Kerneels; Josipovic, Miroslav; van Zyl, Pieter; Kulmala, Markku; Laakso, Lauri

    2013-04-01

    The largest uncertainties in the current global climate models originate from aerosol particle effects (IPCC, 2007) and at the same time aerosol particles also pose a threat to human health (Pope and Dockery, 2006). In southern Africa wild fires and prescribed burning are one of the most important sources of aerosol particles, especially during the dry season from June to September (e.g. Swap et al., 2003; Vakkari et al., 2012). The aerosol particle emissions from savannah fires in southern Africa have been studied in several intensive campaigns such as SAFARI 1992 and 2000 (Swap et al., 2003). However, all previous measurements have been carried out during the daytime, whereas most of the prescribed fires in southern Africa are lit up only after sunset. Furthermore, the previous campaigns followed the plume evolution for up to one hour after emission only. In this study, combining remote sensing fire observations to ground-based long-term measurements of aerosol particle and trace gas properties at the Welgegund measurement station (www.welgegund.org), we have been able to follow the time evolution of savannah fire plumes up to several hours in the atmosphere. For the first time the aerosol particle size distribution measurements in savannah fire plumes cover both day and night time plumes and also the ultrafine size range below 100 nm. During the period from May 20th 2010 to April 15th 2012 altogether 61 savannah fire plumes were observed at Welgegund. The evolution of the aerosol size distribution remained rapid for at least five hours after the fire: during this period the growth rate of the aerosol particle count mean diameter (size range 12 to 840 nm) was 24 nm h-1 for daytime plumes and 8 nm h-1 for night time plumes. The difference in the day and night time growth rate shows that photochemical reactions significantly increase the condensable vapour concentration in the plume. Furthermore, the condensable vapour concentration was found to affect both the

  4. Atmospheric inversion of SO2 and primary aerosol emissions for the year 2010

    NASA Astrophysics Data System (ADS)

    Huneeus, N.; Boucher, O.; Chevallier, F.

    2013-07-01

    Natural and anthropogenic emissions of primary aerosols and sulphur dioxide (SO2) are estimated for the year 2010 by assimilating daily total and fine mode aerosol optical depth (AOD) at 550 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument into a global aerosol model of intermediate complexity. The system adjusts monthly emission fluxes over a set of predefined regions tiling the globe. The resulting aerosol emissions improve the model performance, as measured from usual skill scores, both against the assimilated observations and a set of independent ground-based measurements. The estimated emission fluxes are 67 Tg S yr-1 for SO2, 12 Tg yr-1 for black carbon (BC), 87 Tg yr-1 for particulate organic matter (POM), 17 000 Tg yr-1 for sea salt (SS, estimated at 80 % relative humidity) and 1206 Tg yr-1 for desert dust (DD). They represent a difference of +53, +73, +72, +1 and -8%, respectively, with respect to the first guess (FG) values. Constant errors throughout the regions and the year were assigned to the a priori emissions. The analysis errors are reduced with respect to the a priori ones for all species and throughout the year, they vary between 3 and 18% for SO2, 1 and 130% for biomass burning, 21 and 90 % for fossil fuel, 1 and 200% for DD and 1 and 5% for SS. The maximum errors on the global-yearly scale for the estimated fluxes (considering temporal error dependence) are 3% for SO2, 14% for BC, 11% for POM, 14% for DD and 2% for SS. These values represent a decrease as compared to the global-yearly errors from the FG of 7% for SO2, 40% for BC, 55% for POM, 81% for DD and 300% for SS. The largest error reduction, both monthly and yearly, is observed for SS and the smallest one for SO2. The sensitivity and robustness of the inversion system to the choice of the first guess emission inventory is investigated by using different combinations of inventories for industrial, fossil fuel and biomass burning sources. The initial

  5. Atmospheric inversion of SO2 and primary aerosol emissions for the year 2010

    NASA Astrophysics Data System (ADS)

    Huneeus, N.; Boucher, O.; Chevallier, F.

    2013-03-01

    Natural and anthropogenic emissions of primary aerosols and sulphur dioxide (SO2) are estimated for the year 2010 by assimilating daily total and fine mode aerosol optical depth (AOD) at 550 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument into a global aerosol model of intermediate complexity. The system adjusts monthly emission fluxes over a set of predefined regions tiling the globe. The resulting aerosol emissions improve the model performance, as measured from usual skill scores, both against the assimilated observations and a set of independent ground-based measurements. The estimated emission fluxes are 67 Tg S yr-1 for SO2, 12 Tg yr-1 for black carbon (BC), 87 Tg yr-1 for particulate organic matter (POM), 17 Pg yr-1 for sea salt (SS, estimated at 80% relative humidity) and 1206 Tg yr-1 for desert dust (DD). They represent a difference of +53%, +73%, +72%, +1% and -8%, respectively, with respect to the first guess (FG) values. Constant errors throughout the regions and the year were assigned to the a priori emissions. The analysis errors are reduced for all species and throughout the year, they vary between 3% and 17% for SO2, 1% and 130% for biomass burning, 25% and 89% for fossil fuel, 1% and 200% for DD and 1% and 5% for SS. The maximum errors on the global-annual scale for the estimated fluxes (considering temporal error dependence) are 12% for SO2, 39% for BC, 41% for POM, 43% for DD and 40% for SS. These values represent a decrease as compared to the global-annual errors from the FG of 12% for SO2, 42% for BC, 47% for POM, 50% for DD and 95% for SS. The largest error reduction, both monthly and yearly, is observed for SS and the smallest one for SO2. The sensitivity and robustness of the inversion system to the choice of the first guess emission inventory is investigated by using different combinations of inventories for industrial, fossil fuel and biomass burning sources. The initial difference in the emissions

  6. Model studies on the global impact of aviation emissions on aerosol and climate

    NASA Astrophysics Data System (ADS)

    Righi, M.; Hendricks, J.; Sausen, R.

    2015-12-01

    We use the EMAC global model with the aerosol module MADE to quantify the impact of aviation emissions on the global aerosol. We focus on the year 2000, prescribing the emissions according to the CMIP5 inventory, and on the year 2030, according to the four RCP scenarios. Various sensitivity experiments are performed to further quantify: (i) the uncertainty behind different assumptions on the size distribution of aviation-emitted particles; (ii) the effect of aviation fuel sulfur content on the simulated impacts; (iii) the linearity of the system's response to emission perturbation. The simulations show that the aviation impact on particle mass (black carbon and sulfate) is small, on the order of a few percent, whereas a large effect is found for particle number. In the northern mid-latitudes' upper troposphere (7-12 km), up to 30-40% of the modelled particle number concentration is attributable to aviation. Significant effects are also simulated at the ground, due to the emissions from landing and take-off cycles. The aviation induced perturbations to the particle number concentrations are very sensitive to the assumptions on the size distribution of emitted particles and on the fuel sulfur content. The simulated aviation-induced RF in the year 2000 is in the range of -69.5 to 2.4 mW/m2. The bulk of this RF is due to aerosol-cloud effects, in particular to the perturbation of low clouds. All RCP scenarios project an increase in the aviation impact in 2030, ranging between a factor of 2 to 4 with respect to 2000, albeit with large uncertainties.

  7. Variation in aerosol nucleation and growth in coal-fired power plant plumes due to background aerosol, meteorology and emissions: sensitivity analysis and parameterization.

    NASA Astrophysics Data System (ADS)

    Stevens, R. G.; Lonsdale, C. L.; Brock, C. A.; Reed, M. K.; Crawford, J. H.; Holloway, J. S.; Ryerson, T. B.; Huey, L. G.; Nowak, J. B.; Pierce, J. R.

    2012-04-01

    New-particle formation in the plumes of coal-fired power plants and other anthropogenic sulphur sources may be an important source of particles in the atmosphere. It remains unclear, however, how best to reproduce this formation in global and regional aerosol models with grid-box lengths that are 10s of kilometres and larger. The predictive power of these models is thus limited by the resultant uncertainties in aerosol size distributions. In this presentation, we focus on sub-grid sulphate aerosol processes within coal-fired power plant plumes: the sub-grid oxidation of SO2 with condensation of H2SO4 onto newly-formed and pre-existing particles. Based on the results of the System for Atmospheric Modelling (SAM), a Large-Eddy Simulation/Cloud-Resolving Model (LES/CRM) with online TwO Moment Aerosol Sectional (TOMAS) microphysics, we develop a computationally efficient, but physically based, parameterization that predicts the characteristics of aerosol formed within coal-fired power plant plumes based on parameters commonly available in global and regional-scale models. Given large-scale mean meteorological parameters, emissions from the power plant, mean background condensation sink, and the desired distance from the source, the parameterization will predict the fraction of the emitted SO2 that is oxidized to H2SO4, the fraction of that H2SO4 that forms new particles instead of condensing onto preexisting particles, the median diameter of the newly-formed particles, and the number of newly-formed particles per kilogram SO2 emitted. We perform a sensitivity analysis of these characteristics of the aerosol size distribution to the meteorological parameters, the condensation sink, and the emissions. In general, new-particle formation and growth is greatly reduced during polluted conditions due to the large preexisting aerosol surface area for H2SO4 condensation and particle coagulation. The new-particle formation and growth rates are also a strong function of the

  8. Monitoring of atmospheric aerosol emissions using a remotely piloted air vehicle (RPV)-Borne Sensor Suite

    SciTech Connect

    1996-05-01

    We have developed a small sensor system, the micro-atmospheric measurement system ({mu}-AMS), to monitor and track aerosol emissions. The system was developed to fly aboard a remotely piloted air vehicle, or other mobile platform, to provide real-time particle measurements in effluent plumes and to collect particles for chemical analysis. The {mu}-AMS instrument measures atmospheric parameters including particle mass concentration and size distribution, temperature, humidity, and airspeed, altitude and position (by GPS receiver) each second. The sensor data are stored onboard and are also down linked to a ground station in real time. The {mu}-AMS is battery powered, small (8 in. dia x 36 in.), and lightweight (15 pounds). Aerosol concentrations and size distributions from above ground explosive tests, airbone urban pollution, and traffic-produced particulates are presented.

  9. Detailed Chemical Characterization of Unresolved Complex Mixtures (UCM) inAtmospheric Organics: Insights into Emission Sources, Atmospheric Processing andSecondary Organic Aerosol Formation

    EPA Science Inventory

    Recent studies suggest that semivolatile organic compounds (SVOCs) are important precursors to secondary organic aerosol (SOA) in urban atmospheres. However, knowledge of the chemical composition of SVOCs is limited by current analytical techniques, which are typically unable to...

  10. Organic Aerosol Formation and Processing in the Los Angeles Basin: Role of Gasoline vs. Diesel Emissions

    NASA Astrophysics Data System (ADS)

    Bahreini, R.; Middlebrook, A. M.; De Gouw, J. A.; Warneke, C.; Trainer, M.; Brown, S. S.; Dube, B.; Holloway, J. S.; Perring, A. E.; Schwarz, J. P.; Spackman, J. R.; Stark, H.; Wagner, N.; Parrish, D. D.

    2011-12-01

    During the CalNex-2010 field project in May-June 2010, the NOAA WP-3D aircraft performed flights up- and down-wind of metropolitan, industrial, agricultural and animal feeding sites in central-southern California. Here airborne data on organic aerosol (OA) properties as measured by a compact time-of-flight aerosol mass spectrometer along with measurements of trace gases affecting secondary production of aerosols in the Los Angeles Basin are presented. The analysis presented indicates that the ratio of organic aerosol to carbon monoxide (OA/CO) is significantly higher than the previously observed ratios of primary OA/CO downwind of urban areas, indicating that even on short time scales of transport within the basin, there is significant production of secondary organic aerosol (SOA). The increase in the ratio of OA/CO is also accompanied by an increase in the fraction of oxygenated species of OA, providing evidence for production of more oxidized SOA as air masses are photochemically processed. Despite a smaller contribution from Diesel vehicles to traffic on weekends, analysis of the weekend vs. weekday data indicates that similar values of ΔOA/ΔCO are observed on the weekends compared to weekdays, for air masses with similar degrees of photochemical processing. This indicates that emissions of gas phase organic species from Diesel vehicles are not significant for OA production in the LA Basin. Our calculated steady-state concentrations of hydroxyl radical (OH) indicate that OH concentrations at mid-day are substantially higher on weekends compared to weekdays, indicating faster chemical processing of air masses during a fixed length of time on the weekends compared to weekdays.

  11. The Effect of Changes in Polar Sea Ice on Emissions of Marine Aerosols

    NASA Astrophysics Data System (ADS)

    Matrai, P.; Gabric, A. J.

    2015-12-01

    Cloud radiative effects remain a major weakness in our understanding of the climate system and consequently in developing accurate climate projections. This is mainly true for Arctic low-level clouds in their key role of regulating surface energy fluxes which affect the freezing and melting of sea ice. The radiative properties of clouds are strongly dependent on the number concentration of airborne water-soluble particles, known as cloud condensation nuclei (CCN). In the Arctic, the aerosol-cloud-radiation relationship is more complex than elsewhere and the clouds constitute a warming factor for climate, rather than cooling, most of the year. This is due to the semi-permanent ice cover, which raises the albedo of the surface, and the clean Arctic air, which decreases the albedo of the clouds. There has been much discussion on the relative magnitude of the biogenic source of polar CCN: Primary organic marine aerosols and/or sulfate-containing aerosols, derived from marine emissions. Regional field measurements and pan- (Ant)Arctic model simulations don't necessarily agree. Arctic CCN are formed primarily by aggregates of marine organic material and may grow in mass by condensation. Southern Ocean aerosols may be dominated by sulfate particles and organic particles at lower and higher Antarctic latitudes, respectively. The interaction of polar marine microorganisms, seasonality, sea ice cover, presence or absence of sea spray, and atmospheric heterogeneous processes combine to control natural aerosol concentrations and mass, thus modulating the sensitivity of cloud properties, including their reflectivity and the resulting regional radiation budget. We discuss Arctic and Antarctic field and satellite observations and establish a strong and fundamental link between the biology at the ocean/sea ice interface, clouds and climate over polar regions.

  12. Effects of anthropogenic emissions on aerosol formation from isoprene and monoterpenes in the southeastern United States

    PubMed Central

    Xu, Lu; Guo, Hongyu; Boyd, Christopher M.; Klein, Mitchel; Bougiatioti, Aikaterini; Cerully, Kate M.; Hite, James R.; Kreisberg, Nathan M.; Knote, Christoph; Olson, Kevin; Koss, Abigail; Goldstein, Allen H.; Hering, Susanne V.; de Gouw, Joost; Baumann, Karsten; Lee, Shan-Hu; Nenes, Athanasios; Weber, Rodney J.; Ng, Nga Lee

    2015-01-01

    Secondary organic aerosol (SOA) constitutes a substantial fraction of fine particulate matter and has important impacts on climate and human health. The extent to which human activities alter SOA formation from biogenic emissions in the atmosphere is largely undetermined. Here, we present direct observational evidence on the magnitude of anthropogenic influence on biogenic SOA formation based on comprehensive ambient measurements in the southeastern United States (US). Multiple high-time-resolution mass spectrometry organic aerosol measurements were made during different seasons at various locations, including urban and rural sites in the greater Atlanta area and Centreville in rural Alabama. Our results provide a quantitative understanding of the roles of anthropogenic SO2 and NOx in ambient SOA formation. We show that isoprene-derived SOA is directly mediated by the abundance of sulfate, instead of the particle water content and/or particle acidity as suggested by prior laboratory studies. Anthropogenic NOx is shown to enhance nighttime SOA formation via nitrate radical oxidation of monoterpenes, resulting in the formation of condensable organic nitrates. Together, anthropogenic sulfate and NOx can mediate 43–70% of total measured organic aerosol (29–49% of submicron particulate matter, PM1) in the southeastern US during summer. These measurements imply that future reduction in SO2 and NOx emissions can considerably reduce the SOA burden in the southeastern US. Updating current modeling frameworks with these observational constraints will also lead to more accurate treatment of aerosol formation for regions with substantial anthropogenic−biogenic interactions and consequently improve air quality and climate simulations. PMID:25535345

  13. Temporal variability in emission category influence on organic matter aerosols in the Indian region

    NASA Astrophysics Data System (ADS)

    Cherian, R.; Venkataraman, C.; Ramachandran, S.

    2009-03-01

    The dependence of carbonaceous aerosol properties, like radiation absorption and hygroscopicity, on the emission source of origin motivate this work. The influence of emission categories, including crop residue and forest burning, biofuel combustion, brick kilns, thermal power plants, diesel transport and ``other industry'', is estimated on organic matter (OM) surface concentrations in the Indian ocean region. The approach uses general circulation model predicted OM surface concentrations during a ship cruise, identifies probable source regions for high concentration episodes using the potential source contribution function, and estimates collocated OM emissions resolved by category. Distinct source regions identified, are the Indo-Gangetic Plain during 20-30th January, 1999, and central/south India during 1-11th March, 1999. Contributing emission categories are primarily biofuel combustion (18 Gg) during 20-30th January, but a combination of forest burning (8 Gg), biofuel combustion (7 Gg) and crop residue (5 Gg) during 1-11th March. The magnitude of emission flux rather than spatial extent of an emission category, was seen to increase its influence on the receptor. This approach can be used to investigate seasonal and inter-annual variability in emission category influence on atmospheric pollutants.

  14. Simulating and Analyzing Long-Term Changes in Emissions, Air Quality, Aerosol Feedback Effects and Human Health

    EPA Science Inventory

    This presentation covers work performed by the authors to characterize changes in emissions over the 1990 – 2010 time period, quantify the effects of these emission changes on air quality and aerosol/radiation feedbacks using both observations and model simulations, and fin...

  15. Light absorption properties and radiative effects of primary organic aerosol emissions.

    PubMed

    Lu, Zifeng; Streets, David G; Winijkul, Ekbordin; Yan, Fang; Chen, Yanju; Bond, Tami C; Feng, Yan; Dubey, Manvendra K; Liu, Shang; Pinto, Joseph P; Carmichael, Gregory R

    2015-04-21

    Organic aerosols (OAs) in the atmosphere affect Earth's energy budget by not only scattering but also absorbing solar radiation due to the presence of the so-called "brown carbon" (BrC) component. However, the absorptivities of OAs are not represented or are poorly represented in current climate and chemical transport models. In this study, we provide a method to constrain the BrC absorptivity at the emission inventory level using recent laboratory and field observations. We review available measurements of the light-absorbing primary OA (POA), and quantify the wavelength-dependent imaginary refractive indices (kOA, the fundamental optical parameter determining the particle's absorptivity) and their uncertainties for the bulk POA emitted from biomass/biofuel, lignite, propane, and oil combustion sources. In particular, we parametrize the kOA of biomass/biofuel combustion sources as a function of the black carbon (BC)-to-OA ratio, indicating that the absorptive properties of POA depend strongly on burning conditions. The derived fuel-type-based kOA profiles are incorporated into a global carbonaceous aerosol emission inventory, and the integrated kOA values of sectoral and total POA emissions are presented. Results of a simple radiative transfer model show that the POA absorptivity warms the atmosphere significantly and leads to ∼27% reduction in the amount of the net global average POA cooling compared to results from the nonabsorbing assumption.

  16. Excitation-emission spectra and fluorescence quantum yields for fresh and aged biogenic secondary organic aerosols.

    PubMed

    Lee, Hyun Ji Julie; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A

    2013-06-04

    Certain biogenic secondary organic aerosols (SOA) become absorbent and fluorescent when exposed to reduced nitrogen compounds such as ammonia, amines, and their salts. Fluorescent SOA may potentially be mistaken for biological particles by detection methods relying on fluorescence. This work quantifies the spectral distribution and effective quantum yields of fluorescence of water-soluble SOA generated from two monoterpenes, limonene and α-pinene, and two different oxidants, ozone (O3) and hydroxyl radical (OH). The SOA was generated in a smog chamber, collected on substrates, and aged by exposure to ∼100 ppb ammonia in air saturated with water vapor. Absorption and excitation-emission matrix (EEM) spectra of aqueous extracts of aged and control SOA samples were measured, and the effective absorption coefficients and fluorescence quantum yields (∼0.005 for 349 nm excitation) were determined from the data. The strongest fluorescence for the limonene-derived SOA was observed for λexcitation = 420 ± 50 nm and λemission = 475 ± 38 nm. The window of the strongest fluorescence shifted to λexcitation = 320 ± 25 nm and λemission = 425 ± 38 nm for the α-pinene-derived SOA. Both regions overlap with the EEM spectra of some of the fluorophores found in primary biological aerosols. Despite the low quantum yield, the aged SOA particles may have sufficient fluorescence intensities to interfere with the fluorescence detection of common bioaerosols.

  17. Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the southeast United States and co-benefit of SO2 emission controls

    EPA Science Inventory

    Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for...

  18. Attribution of aerosol radiative forcing over India during the winter monsoon to emissions from source categories and geographical regions

    NASA Astrophysics Data System (ADS)

    Verma, S.; Venkataraman, C.; Boucher, O.

    2011-08-01

    We examine the aerosol radiative effects due to aerosols emitted from different emission sectors (anthropogenic and natural) and originating from different geographical regions within and outside India during the northeast (NE) Indian winter monsoon (January-March). These studies are carried out through aerosol transport simulations in the general circulation (GCM) model of the Laboratoire de Météorologie Dynamique (LMD). The model estimates of aerosol single scattering albedo (SSA) show lower values (0.86-0.92) over the region north to 10°N comprising of the Indian subcontinent, Bay of Bengal, and parts of the Arabian Sea compared to the region south to 10°N where the estimated SSA values lie in the range 0.94-0.98. The model estimated SSA is consistent with the SSA values inferred through measurements on various platforms. Aerosols of anthropogenic origin reduce the incoming solar radiation at the surface by a factor of 10-20 times the reduction due to natural aerosols. At the top-of-atmosphere (TOA), aerosols from biofuel use cause positive forcing compared to the negative forcing from fossil fuel and natural sources in correspondence with the distribution of SSA which is estimated to be the lowest (0.7-0.78) from biofuel combustion emissions. Aerosols originating from India and Africa-west Asia lead to the reduction in surface radiation (-3 to -8 W m -2) by 40-60% of the total reduction in surface radiation due to all aerosols over the Indian subcontinent and adjoining ocean. Aerosols originating from India and Africa-west Asia also lead to positive radiative effects at TOA over the Arabian Sea, central India (CNI), with the highest positive radiative effects over the Bay of Bengal and cause either negative or positive effects over the Indo-Gangetic plain (IGP).

  19. Particulate PAH emissions from residential biomass combustion: time-resolved analysis with aerosol mass spectrometry.

    PubMed

    Eriksson, A C; Nordin, E Z; Nyström, R; Pettersson, E; Swietlicki, E; Bergvall, C; Westerholm, R; Boman, C; Pagels, J H

    2014-06-17

    Time-resolved emissions of particulate polycyclic aromatic hydrocarbons (PAHs) and total organic particulate matter (OA) from a wood log stove and an adjusted pellet stove were investigated with high-resolution time-of-flight aerosol mass spectrometry (AMS). The highest OA emissions were found during the addition of log wood on glowing embers, that is, slow burning pyrolysis conditions. These emissions contained about 1% PAHs (of OA). The highest PAH emissions were found during fast burning under hot air starved combustion conditions, in both stoves. In the latter case, PAHs contributed up to 40% of OA, likely due to thermal degradation of other condensable species. The distribution of PAHs was also shifted toward larger molecules in these emissions. AMS signals attributed to PAHs were found at molecular weights up to 600 Da. The vacuum aerodynamic size distribution was found to be bimodal with a smaller mode (Dva ∼ 200 nm) dominating under hot air starved combustion and a larger sized mode dominating under slow burning pyrolysis (Dva ∼ 600 nm). Simultaneous reduction of PAHs, OA and total particulate matter from residential biomass combustion may prove to be a challenge for environmental legislation efforts as these classes of emissions are elevated at different combustion conditions.

  20. Regional-scale simulations of fungal spore aerosols using an emission parameterization adapted to local measurements of fluorescent biological aerosol particles

    NASA Astrophysics Data System (ADS)

    Hummel, M.; Hoose, C.; Gallagher, M.; Healy, D. A.; Huffman, J. A.; O'Connor, D.; Pöschl, U.; Pöhlker, C.; Robinson, N. H.; Schnaiter, M.; Sodeau, J. R.; Toprak, E.; Vogel, H.

    2014-04-01

    Fungal spores as a prominent type of primary biological aerosol particles (PBAP) have been incorporated into the COSMO-ART regional atmospheric model, using and comparing three different emission parameterizations. Two literature-based emission rates derived from fungal spore colony counts and chemical tracer measurements were used as a parameterization baseline for this study. A third, new emission parameterization was adapted to field measurements of fluorescent biological aerosol particles (FBAP) from four locations across Northern Europe. FBAP concentrations can be regarded as a lower estimate of total PBAP concentrations. Size distributions of FBAP often show a distinct mode at approx. 3 μm, corresponding to a diameter range characteristic for many fungal spores. Previous studies have suggested the majority of FBAP in several locations are dominated by fungal spores. Thus, we suggest that simulated fungal spore concentrations obtained from the emission parameterizations can be compared to the sum of total FBAP concentrations. A comparison reveals that parameterized estimates of fungal spore concentrations based on literature numbers underestimate measured FBAP concentrations. In agreement with measurement data, the model results show a diurnal cycle in simulated fungal spore concentrations, which may develop partially as a consequence of a varying boundary layer height between day and night. Measured FBAP and simulated fungal spore concentrations also correlate similarly with simulated temperature and humidity. These meteorological variables, together with leaf area index, were chosen to drive the new emission parameterization discussed here. Using the new emission parameterization on a model domain covering Western Europe, fungal spores in the lowest model layer comprise a fraction of 15% of the total aerosol mass over land and reach average number concentrations of 26 L-1. The results confirm that fungal spores and biological particles may account for a

  1. Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA): Introduction and overview

    PubMed Central

    Godleski, John J.; Rohr, Annette C.; Kang, Choong M.; Diaz, Edgar A.; Ruiz, Pablo A.; Koutrakis, Petros

    2013-01-01

    Determining the health impacts of sources and components of fine particulate matter (PM2.5) is an important scientific goal. PM2.5 is a complex mixture of inorganic and organic constituents that are likely to differ in their potential to cause adverse health outcomes. The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study focused on two PM sources—coal-fired power plants and mobile sources—and sought to investigate the toxicological effects of exposure to emissions from these sources. The set of papers published here document the power plant experiments. TERESA attempted to delineate health effects of primary particles, secondary (aged) particles, and mixtures of these with common atmospheric constituents. TERESA involved withdrawal of emissions from the stacks of three coal-fired power plants in the United States. The emissions were aged and atmospherically transformed in a mobile laboratory simulating downwind power plant plume processing. Toxicological evaluations were carried out in laboratory rats exposed to different emission scenarios with extensive exposure characterization. The approach employed in TERESA was ambitious and innovative. Technical challenges included the development of stack sampling technology that prevented condensation of water vapor from the power plant exhaust during sampling and transfer, while minimizing losses of primary particles; development and optimization of a photochemical chamber to provide an aged aerosol for animal exposures; development and evaluation of a denuder system to remove excess gaseous components; and development of a mobile toxicology laboratory. This paper provides an overview of the conceptual framework, design, and methods employed in the study. PMID:21639692

  2. Investigating the impacts of aviation NOX, SO2 and black carbon emissions on ozone, aerosol and climate.

    NASA Astrophysics Data System (ADS)

    Kapadia, Zarashpe; Borman, Duncan; Spracklen, Dominick; Arnold, Stephen; Mann, Graham; Williams, Paul

    2013-04-01

    Aviation is currently responsible for 3% of global anthropogenic CO2 emissions, but 2-14% of anthropogenic induced warming due to the co-emission of NOX, SO2 and black carbon and formation of contrails. The impact of aviation emissions on ozone and aerosol is uncertain with recent research demonstrating the need to include atmospheric nitrate chemistry. The inclusion of nitrate chemistry may lead to a 20% reduction in aviation induced ozone forcing estimates due to the competition for atmospheric oxidants such as OH . Compounding this, uncertainties relating to the effects of NOx on ozone and methane illustrate the need for refining the understanding of aviation induced impacts. Furthermore the role of aerosol microphysics in controlling the climate impacts of aviation has not yet been explored. Here we use the TOMCAT 3-D chemical transport model coupled to the GLOMAP-mode aerosol microphysics model to quantify the impacts of aviation NOX, SO2 and BC emissions on ozone, aerosol and climate. GLOMAP-mode treats size resolved aerosol using a two-moment modal approach. We evaluate the effects of nitrate processing on the diagnosed impacts of aviation emissions on atmospheric composition including the first assessment of the impact on the global concentrations of cloud condensation nuclei. We investigate interactions between gas-phase oxidant photochemistry and aerosol microphysics in regions influenced by aircraft emissions, using fully-coupled tropospheric chemistry and multi-component aerosol treatment (BC, sulphate, nitrate). Finally, we use a 3-D radiative transfer model to quantify the ozone and aerosol direct and indirect radiative effects of aviation emissions. The work presented here is part of a wider research project which will be the first study to combine aviation NOX, SO2 and black carbon emission in a global size-resolved model which considers atmospheric nitrate chemistry, which will aim to add to the science surrounding present day aviation impacts by

  3. Aerosol Radiative Forcing Estimates from South Asian Clay Brick Production Based on Direct Emission Measurements

    NASA Astrophysics Data System (ADS)

    Weyant, C.; Athalye, V.; Ragavan, S.; Rajarathnam, U.; Kr, B.; Lalchandani, D.; Maithel, S.; Malhotra, G.; Bhanware, P.; Thoa, V.; Phuong, N.; Baum, E.; Bond, T. C.

    2012-12-01

    About 150-200 billion clay bricks are produced in India every year. Most of these bricks are fired in small-scale traditional kilns that burn coal or biomass without pollution controls. Reddy and Venkataraman (2001) estimated that 8% of fossil fuel related PM2.5 emissions and 23% of black carbon emissions in India are released from brick production. Few direct emissions measurements have been done in this industry and black carbon emissions, in particular, have not been previously measured. In this study, 9 kilns representing five common brick kiln technologies were tested for aerosol properties and gaseous pollutant emissions, including optical scattering and absorption and thermal-optical OC/EC. Simple relationships are then used to estimate the radiative-forcing impact. Kiln design and fuel quality greatly affect the overall emission profiles and relative climate warming. Batch production kilns, such as the Downdraft kiln, produce the most PM2.5 (0.97 gPM2.5/fired brick) with an OC/EC fraction of 0.3. Vertical Shaft Brick kilns using internally mixed fuels produce the least PM (0.09 gPM2.5/kg fired brick) with the least EC (OC/EC = 16.5), but these kilns are expensive to implement and their use throughout Southern Asia is minimal. The most popular kiln in India, the Bull's Trench kiln, had fewer emissions per brick than the Downdraft kiln, but an even higher EC fraction (OC/EC = 0.05). The Zig-zag kiln is similar in structure to the Bull's Trench kiln, but the emission factors are significantly lower: 50% reduction for CO, 17% for PM2.5 and 60% for black carbon. This difference in emissions suggests that converting traditional Bull's Trench kilns into less polluting Zig-zag kilns would result in reduced atmospheric warming from brick production.

  4. Efficient Formation of Stratospheric Aerosol for Climate Engineering by Emission of Condensible Vapor from Aircraft

    NASA Technical Reports Server (NTRS)

    Pierce, Jeffrey R.; Weisenstein, Debra K.; Heckendorn, Patricia; Peter. Thomas; Keith, David W.

    2010-01-01

    Recent analysis suggests that the effectiveness of stratospheric aerosol climate engineering through emission of non-condensable vapors such as SO2 is limited because the slow conversion to H2SO4 tends to produce aerosol particles that are too large; SO2 injection may be so inefficient that it is difficult to counteract the radiative forcing due to a CO2 doubling. Here we describe an alternate method in which aerosol is formed rapidly in the plume following injection of H2SO4, a condensable vapor, from an aircraft. This method gives better control of particle size and can produce larger radiative forcing with lower sulfur loadings than SO2 injection. Relative to SO2 injection, it may reduce some of the adverse effects of geoengineering such as radiative heating of the lower stratosphere. This method does not, however, alter the fact that such a geoengineered radiative forcing can, at best, only partially compensate for the climate changes produced by CO2.

  5. Top-down constraints to aerosol emissions from open biomass burning: the role of gas-particle partitioning and secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Konovalov, Igor B.; Beekmann, Matthias; Berezin, Evgeny V.; Petetin, Hervé

    2014-05-01

    Open biomass burning (BB), including wildfires and controlled burns in agriculture and foresty, is known to provide an important contribution to organic aerosol (OA) and black carbon (BC) emissions on the global scale. However, quantitative estimates of BB aerosol emissions and their effects on climate and environment remain rather uncertain. A useful way to constrain the OA&BC emissions involves using atmospheric measurements in the framework of the inverse modeling approach. In such an approach, the relationship between the emissions and the measurements is simulated by a chemistry transport model; this means that top-down estimates may be sensitive to possible model uncertainties. As a result of assimilation of satellite measurements of aerosol optical depth, several recent studies (e.g. [1,2]) indicated that aerosol emissions provided by bottom-up emission inventories may be strongly underestimated relative to emissions of gaseous species (such as CO). Meanwhile, it was earlier shown (e.g. [3]) that the relationship between primary organic aerosol emissions and aerosol concentration in the atmosphere can be significantly affected by gas-particle partitioning and oxidation of lower-volatility organic emissions; these processes are usually not taken into account in typical chemistry transport models. The main goal of this study was to examine to what degree the discrepancy between the OA&BC/CO emission ratios predicted by the bottom-up inventories and derived from satellite observations can be associated with the mentioned processes and explained in the framework of the volatility basis set approach (VBS) [3] to OA modelling. To achieve this goal, a VBS scheme, which was recently implemented in the CHIMERE chemistry transport model (CTM), was first modified to account for OA emissions from biomass burning. An ensemble of simulations with the CHIMERE CTM was then performed for the case of the 2010 mega-fire event in European Russia [4]; each of the simulations

  6. Atmospheric emitted radiance interferometer (AERI): Status and the aerosol explanation for extra window region emissions

    SciTech Connect

    Revercomb, H.E.; Knuteson, R.O.; Best, F.A.; Dirkx, T.P.

    1996-04-01

    High spectral resolution observations of downwelling emission from 3 to 19 microns have been made by the Atmospheric Emitted Radiance Interferometer (AERI) Prototype at the Southern Great Plains (SGP) Cloud and Radiative Testbed (CART) site for over two years. The spectral data set from AERI provides a basis for improving clear sky radiative transfer; determining the radiative impact of clouds, including the derivation of cloud radiative properties; defining the influences of aerosols in the window regions; and retrieving boundary layer state properties, including temperature, water vapor, and other trace gases. The data stream of radiometrically and spectrally calibrated radiances is routinely provided by Pacific Northwest Laboratory (PNL) to those science teams requesting it, and further information on the instrument and data characteristics is available in the ARM Science Team proceedings for 1993 and 1994 and in several conference publications. This paper describes the AERI status, calibration, field experiment wit a new AERI-01 and schedule, window region emissions, and future AERI plans.

  7. Mineral Dust Aerosol from Saharan Desert by Means of Atmospheric, Emission, Dispersion Modelling

    NASA Astrophysics Data System (ADS)

    Busillo, C.; Calastrini, F.; Guarnieri, F.; Pasqui, M.; Becagli, S.; Lucarelli, F.; Nava, S.; Udisti, R.

    2011-01-01

    The application of Numerical Prediction Models to mineral dust cycle is considered of prime importance in climate change due to aerosol and non-CO2 greenhouse gases. In this framework, a comprehensive atmospheric, emission, dispersion modelling system was developed in order to provide a regional characterization of Saharan dust intrusions over Mediterranean basin. The model is based on three different modules: the atmospheric model, the dust emission model and transport/deposition model. Numerical modelling simulations for a selected case study, June 2006, was carried out to test the modelling system. The evaluation of the performed analysis shows a good agreement with the in-situ measurements of some specific crustal markers in the PM10 fraction.

  8. Gas-particle partitioning of primary organic aerosol emissions: (1) Gasoline vehicle exhaust

    NASA Astrophysics Data System (ADS)

    May, Andrew A.; Presto, Albert A.; Hennigan, Christopher J.; Nguyen, Ngoc T.; Gordon, Timothy D.; Robinson, Allen L.

    2013-10-01

    The gas-particle partitioning of the primary organic aerosol (POA) emissions from fifty-one light-duty gasoline vehicles (model years 1987-2012) was investigated at the California Air Resources Board Haagen-Smit Laboratory. Each vehicle was operated over the cold-start unified cycle on a chassis dynamometer and its emissions were sampled using a constant volume sampler. Four independent yet complementary approaches were used to investigate POA gas-particle partitioning: sampling artifact correction of quartz filter data, dilution from the constant volume sampler into a portable environmental chamber, heating in a thermodenuder, and thermal desorption/gas chromatography/mass spectrometry analysis of quartz filter samples. This combination of techniques allowed gas-particle partitioning measurements to be made across a wide range of atmospherically relevant conditions - temperatures of 25-100 °C and organic aerosol concentrations of <1-600 μg m-3. The gas-particle partitioning of the POA emissions varied continuously over this entire range of conditions and essentially none of the POA should be considered non-volatile. Furthermore, for most vehicles, the low levels of dilution used in the constant volume sampler created particle mass concentrations that were greater than a factor of 10 or higher than typical ambient levels. This resulted in large and systematic partitioning biases in the POA emission factors compared to more dilute atmospheric conditions, as the POA emission rates may be over-estimated by nearly a factor of four due to gas-particle partitioning at higher particle mass concentrations. A volatility distribution was derived to quantitatively describe the measured gas-particle partitioning data using absorptive partitioning theory. Although the POA emission factors varied by more than two orders of magnitude across the test fleet, the vehicle-to-vehicle differences in gas-particle partitioning were modest. Therefore, a single volatility distribution

  9. Epoxide as a Precursor to Secondary Organic Aerosol Formation from Isoprene Photooxidation in the Presence of Nitrogen Oxides

    EPA Science Inventory

    Isoprene is a substantial contributor to the global secondary organic aerosol (SOA) burden, with implications for public health and the climate system. The mechanism by which isoprene-derived SOA is formed and the influence of environmental conditions, however, remain unclear...

  10. Lagrangian Aerosol and Ozone Precursor Forecasts Utilizing NASA Aura OMI NO2 and NOAA GOES-GASP AOD Observations

    EPA Science Inventory

    Over the past decade, the remote sensing of trace gases and aerosols from space has dramatically improved. The emergence and application of these measurements adds a new dimension to air quality Management and forecasting by enabling consistent observations of pollutants over l...

  11. Analysis of particulate emissions from tropical biomass burning using a global aerosol model and long-term surface observations

    NASA Astrophysics Data System (ADS)

    Reddington, Carly L.; Spracklen, Dominick V.; Artaxo, Paulo; Ridley, David A.; Rizzo, Luciana V.; Arana, Andrea

    2016-09-01

    We use the GLOMAP global aerosol model evaluated against observations of surface particulate matter (PM2.5) and aerosol optical depth (AOD) to better understand the impacts of biomass burning on tropical aerosol over the period 2003 to 2011. Previous studies report a large underestimation of AOD over regions impacted by tropical biomass burning, scaling particulate emissions from fire by up to a factor of 6 to enable the models to simulate observed AOD. To explore the uncertainty in emissions we use three satellite-derived fire emission datasets (GFED3, GFAS1 and FINN1). In these datasets the tropics account for 66-84 % of global particulate emissions from fire. With all emission datasets GLOMAP underestimates dry season PM2.5 concentrations in regions of high fire activity in South America and underestimates AOD over South America, Africa and Southeast Asia. When we assume an upper estimate of aerosol hygroscopicity, underestimation of AOD over tropical regions impacted by biomass burning is reduced relative to previous studies. Where coincident observations of surface PM2.5 and AOD are available we find a greater model underestimation of AOD than PM2.5, even when we assume an upper estimate of aerosol hygroscopicity. Increasing particulate emissions to improve simulation of AOD can therefore lead to overestimation of surface PM2.5 concentrations. We find that scaling FINN1 emissions by a factor of 1.5 prevents underestimation of AOD and surface PM2.5 in most tropical locations except Africa. GFAS1 requires emission scaling factor of 3.4 in most locations with the exception of equatorial Asia where a scaling factor of 1.5 is adequate. Scaling GFED3 emissions by a factor of 1.5 is sufficient in active deforestation regions of South America and equatorial Asia, but a larger scaling factor is required elsewhere. The model with GFED3 emissions poorly simulates observed seasonal variability in surface PM2.5 and AOD in regions where small fires dominate, providing

  12. Aerosol emissions of a ship diesel engine operated with diesel fuel or heavy fuel oil.

    PubMed

    Streibel, Thorsten; Schnelle-Kreis, Jürgen; Czech, Hendryk; Harndorf, Horst; Jakobi, Gert; Jokiniemi, Jorma; Karg, Erwin; Lintelmann, Jutta; Matuschek, Georg; Michalke, Bernhard; Müller, Laarnie; Orasche, Jürgen; Passig, Johannes; Radischat, Christian; Rabe, Rom; Reda, Ahmed; Rüger, Christopher; Schwemer, Theo; Sippula, Olli; Stengel, Benjamin; Sklorz, Martin; Torvela, Tiina; Weggler, Benedikt; Zimmermann, Ralf

    2016-05-02

    Gaseous and particulate emissions from a ship diesel research engine were elaborately analysed by a large assembly of measurement techniques. Applied methods comprised of offline and online approaches, yielding averaged chemical and physical data as well as time-resolved trends of combustion by-products. The engine was driven by two different fuels, a commonly used heavy fuel oil (HFO) and a standardised diesel fuel (DF). It was operated in a standardised cycle with a duration of 2 h. Chemical characterisation of organic species and elements revealed higher concentrations as well as a larger number of detected compounds for HFO operation for both gas phase and particulate matter. A noteworthy exception was the concentration of elemental carbon, which was higher in DF exhaust aerosol. This may prove crucial for the assessment and interpretation of biological response and impact via the exposure of human lung cell cultures, which was carried out in parallel to this study. Offline and online data hinted at the fact that most organic species in the aerosol are transferred from the fuel as unburned material. This is especially distinctive at low power operation of HFO, where low volatility structures are converted to the particulate phase. The results of this study give rise to the conclusion that a mere switching to sulphur-free fuel is not sufficient as remediation measure to reduce health and environmental effects of ship emissions.

  13. Sensitivity of dust emissions to aerosol feedback and the impact of dust loading on climate forcing with varied resolutions using FIM-Chem

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Grell, Georg; Henze, Daven; Mckeen, Stuart; Sun, Shan; Li, Haiqin

    2016-04-01

    Meteorological conditions directly impact aerosol loading, especially dust emissions. Variations in dust emissions on the other hand, will also impact meteorology and climate through direct and indirect aerosol forcing. To study these impacts in more detail we use the global Flow-following finite-volume Icosahedra Model (FIM, http://fim.noaa.gov/), a new global weather prediction model currently under development in the Global Systems Division of NOAA/ESRL, as it is coupled online with the aerosol modules from the Goddard Gobal Ozone Chemistry Aerosol Radiation and Transport (GOCART) model (FIM-Chem). FIM-Chem includes direct and semi direct feedback, and uses the dust schemes of GOCART and the Air Force Weather Agency (AFWA). FIM-Chem is able to investigate the contribution of climate feedbacks to simulated hyperspectral data by considering a range of simulations with different dust emissions and different levels of aerosol feedbacks enabled at four different spatial resolutions. The emitted dust flux and total emissions are highly depending on the wind, soil moisture and model resolution. We compare the dust emissions by including and excluding the aerosol radiative feedback in the simulations to quantify the sensitivity of dust emissions to aerosol feedback. The results show that all aerosol-induced dust emissions increase about 10% globally, which is mainly dominated by the contributions of anthropogenic black carbon (EC) aerosol. While the dust-induced percentage changes of dust emissions are about -5.5%, that indicates reduction effect globally. Also, the simulations based on different resolutions of 240x240 km, 120x120 km, 60x60 km and 30x30 km are performed to test the impacts of model resolution on total dust emissions. By comparing the dust emission sensitivity to aerosol feedback and model resolution, we can estimate the uncertainty of model resolution versus aerosol feedback. We also conduct FIM-Chem simulations to investigate the sensitivity of dust

  14. Regional-scale simulations of fungal spore aerosols using an emission parameterization adapted to local measurements of fluorescent biological aerosol particles

    NASA Astrophysics Data System (ADS)

    Hummel, M.; Hoose, C.; Gallagher, M.; Healy, D. A.; Huffman, J. A.; O'Connor, D.; Pöschl, U.; Pöhlker, C.; Robinson, N. H.; Schnaiter, M.; Sodeau, J. R.; Stengel, M.; Toprak, E.; Vogel, H.

    2015-06-01

    Fungal spores as a prominent type of primary biological aerosol particles (PBAP) have been incorporated into the COSMO-ART (Consortium for Small-scale Modelling-Aerosols and Reactive Trace gases) regional atmospheric model. Two literature-based emission rates for fungal spores derived from fungal spore colony counts and chemical tracer measurements were used as a parameterization baseline for this study. A third, new emission parameterization for fluorescent biological aerosol particles (FBAP) was adapted to field measurements from four locations across Europe. FBAP concentrations can be regarded as a lower estimate of total PBAP concentrations. Size distributions of FBAP often show a distinct mode at approx. 3 μm, corresponding to a diameter range characteristic for many fungal spores. Previous studies for several locations have suggested that FBAP are in many cases dominated by fungal spores. Thus, we suggest that simulated FBAP and fungal spore concentrations obtained from the three different emission parameterizations can be compared to FBAP measurements. The comparison reveals that simulated fungal spore concentrations based on literature emission parameterizations are lower than measured FBAP concentrations. In agreement with the measurements, the model results show a diurnal cycle in simulated fungal spore concentrations, which may develop partially as a consequence of a varying boundary layer height between day and night. Temperature and specific humidity, together with leaf area index (LAI), were chosen to drive the new emission parameterization which is fitted to the FBAP observations. The new parameterization results in similar root mean square errors (RMSEs) and correlation coefficients compared to the FBAP observations as the previously existing fungal spore emission parameterizations, with some improvements in the bias. Using the new emission parameterization on a model domain covering western Europe, FBAP in the lowest model layer comprise a

  15. An Overview of the DAURE Campaign: Aerosols Emissions and Evolution in the Western Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Pandolfi, Marco; Querol, Xavier; Alastuey, Andrés.; Jimenez, Jose L.

    2010-05-01

    DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean) is a multidisciplinary international measurement campaign mainly aimed at estimating the sources and origin of atmospheric fine aerosols in the Western Mediterranean Basin (WMB), with particular attention to the carbonaceous fraction. Main focuses of the campaign are the study of the origin of the intense pollution episodes frequently occurring at regional scale in summer and winter in the WMB (Perez et al., 2008) and the emission, formation, transport and transformation of aerosols during these polluted scenarios. The peculiar atmospheric dynamics in the WMB, regulated by complex climatic and orographic effects (Millán et al., 1997), together with the large pollutant emissions from densely populated areas, large industrial areas and ports located along the coastline, give rise to a complex phenomenology for aerosol formation and transformation. In this context, extremely high concentrations of fine particulate matter (mainly PM1, particulate matter with aerodynamic diameter < 1um) are usually registered at regional background stations, with levels even higher than those simultaneously registered at urban stations. DAURE brings together state-of-the-art measurements and modeling techniques from about 20 International and Spanish Institutions. The DAURE campaign took place during winter (February-March 2009) and summer (July 2009) at an urban site (Barcelona, 80 m a.s.l., NE Spain) and a regional background site (Montseny, 720 m a.s.l., NE Spain, a Supersite of the EUSAAR network). Widespread in situ aerosol sampling techniques (such as PM optical counters, PM samplers, MAAP, CPC, SMPS, Rotating Drum Impactor, among others) and remote sensing techniques (LIDAR, sunphotometer) have been applied together with state-of-the-art methods such as 14C (Szidat et al., 2006), Proton-Transfer Reaction Mass Spectrometry (PTRMS) for VOCs, and High

  16. Stress-induced biogenic VOC emissions from typical European tree species, their impact on secondary organic aerosol formation and possible climate feedbacks

    NASA Astrophysics Data System (ADS)

    Kleist, E.; Mentel, T. F.; Andres, S.; Dal Maso, M.; Hohaus, T.; Kindler-Scharr, A.; Rudich, Y.; Springer, M.; Tillmann, R.; Uerlings, R.; Wahner, A.; Wildt, J.

    2011-12-01

    Biogenic volatile organic compounds (BVOC) are precursors of secondary organic aerosols (SOA), which can scatter and absorb radiation. BVOC therefore indirectly impact the Earth's climate. Earth's climate is projected to change, possibly putting and vegetation under stress due to intensive heat and drought periods. Such stress situations will alter BVOC emissions that may induce feedbacks between vegetation and climate change. The main aim of our study is to determine whether such effect exists. A first step was to determine the impacts of drought and heat on BVOC emissions and subsequent SOA formation. Experiments were performed in the Juelich plant atmosphere chamber. Pine and Spruce were taken as representatives for species exhibiting storage organs for monoterpenes (MT). Beech and Birch were used as species with MT emissions closely coupled to CO2 uptake. The plants were stored under well-defined conditions of temperature and light intensity. Heat stress was induced by increasing the chamber temperature; drought stress was induced by not irrigating the plants. A fraction of the air leaving the plant chamber was fed into a reaction chamber where SOA formation was induced by OH-initiated oxidation. During stress situations the plants' BVOC emissions changed significantly. As a general feature we found that combined heat and drought stress increased MT emissions from conifers but decreased MT emissions from the broadleaf species. The former was attributed to a heat-induced breakdown of storage organs. The latter was attributed to a general breakdown of biosynthetic activity. SOA formation potentials were changed together with the MT emissions. The decrease in SOA formation potential due to the decrease of MT emissions from broadleaf species was amplified by additional emissions of green leaf volatiles (GLV). Obviously, GLV can suppress SOA formation by suppressing OH concentrations. GLV were also emitted from the conifers under heat stress. However the

  17. Influence of Jet Fuel Composition on Aircraft Engine Emissions: A Synthesis of Aerosol Emissions Data from the NASA APEX, AAFEX, and ACCESS Missions

    NASA Astrophysics Data System (ADS)

    Moore, R.; Shook, M.; Beyersdorf, A. J.; Corr, C.; Herndon, S. C.; Knighton, W. B.; Miake-Lye, R. C.; Thornhill, K. L., II; Winstead, E.; Yu, Z.; Ziemba, L. D.; Anderson, B. E.

    2015-12-01

    We statistically analyze the impact of jet fuel properties on aerosols emitted by the NASA McDonnell Douglas DC-8 CFM56-2-C1 engines burning fifteen different aviation fuels. Data were collected for this single engine type during four different, comprehensive ground tests conducted over the past decade, which allow us to clearly link changes in aerosol emissions to fuel compositional changes. It is found that the volatile aerosol fraction dominates the number and volume emissions indices (EIs) over all engine powers, which are driven by changes in fuel aromatic and sulfur content. Meanwhile, the naphthalenic content of the fuel determines the magnitude of the non-volatile number and volume EI as well as the black carbon mass EI. Linear regression coefficients are reported for each aerosol EI in terms of these properties, engine fuel flow rate, and ambient temperature, and show that reducing both fuel sulfur content and napththalenes to near-zero levels would result in roughly a ten-fold decrease in aerosol number emitted per kg of fuel burn. This work informs future efforts to model aircraft emissions changes as the aviation fleet gradually begins to transition toward low-aromatic, low-sulfur alternative jet fuels from bio-based or Fischer-Tropsch production pathways.

  18. Organic aerosol emission ratios from the laboratory combustion of biomass fuels

    NASA Astrophysics Data System (ADS)

    Jolleys, Matthew D.; Coe, Hugh; McFiggans, Gordon; McMeeking, Gavin R.; Lee, Taehyoung; Kreidenweis, Sonia M.; Collett, Jeffrey L.; Sullivan, Amy P.

    2014-11-01

    Organic aerosol (OA) emission ratios (ER) have been characterized for 67 burns during the second Fire Laboratory at Missoula Experiment. These fires involved 19 different species representing 6 major fuels, each of which forms an important contribution to the U.S. biomass burning inventory. Average normalized ΔOA/ΔCO ratios show a high degree of variability, both between and within different fuel types and species, typically exceeding differen-ces between separate plumes in ambient measurements. This variability is strongly influenced by highly contrasting ΔOA levels between burns and the increased partitioning of semivolatile organic compounds to the particle phase at high ΔOA concentrations. No correlation across all fires was observed between ΔOA/ΔCO and modified combustion efficiency (MCE), which acts as an indicator of the proportional contributions of flaming and smoldering combustion phases throughout each burn. However, a negative correlation exists with MCE for some coniferous species, most notably Douglas fir, for which there is also an influence from fuel moisture content. Changes in fire efficiency were also shown to dramatically alter emissions for fires with very similar initial conditions. Although the relationship with MCE is variable between species, there is greater consistency with the level of oxygenation in OA. The ratio of the m/z 44 fragment to total OA mass concentration (f44) as measured by aerosol mass spectrometer provides an indication of oxygenation as influenced by combustion processes at source, with ΔOA/ΔCO decreasing with increasing f44 for all fuel types. Inconsistencies in the magnitude of the effects associated with each potential influence on ΔOA/ΔCO emphasize the lack of a single dominant control on fire emissions, and a dependency on both fuel properties and combustion conditions.

  19. Aerosol-CFD modelling of ultrafine and black carbon particle emission, dilution, and growth near roadways

    NASA Astrophysics Data System (ADS)

    Huang, L.; Gong, S. L.; Gordon, M.; Liggio, J.; Staebler, R. M.; Stroud, C. A.; Lu, G.; Mihele, C.; Brook, J. R.; Jia, C. Q.

    2014-05-01

    Many studies have shown that on-road vehicle emissions are the dominant source of ultrafine particles (UFP; diameter < 100 nm) in urban areas and near-roadway environments. In order to advance our knowledge on the complex interactions and competition among atmospheric dilution, dispersion and dynamics of UFPs, an aerosol dynamics-CFD coupled model is developed and validated against field measurements. A unique approach of applying periodic boundary conditions is proposed to model pollutant dispersion and dynamics in one unified domain from the tailpipe level to the ambient near-road environment. This approach significantly reduces the size of the computational domain, and therefore, allows fast simulation of multiple scenarios. The model is validated against measured turbulent kinetic energy (TKE) and pollution gradients near a major highway. Through a model sensitivity analysis, the relative importance of individual aerosol dynamical processes on the total particle number concentration (N) and particle number-size distribution (PSD) near a highway is investigated. The results demonstrate that (1) coagulation has a negligible effect on N and particle growth, (2) binary homogeneous nucleation (BHN) of H2SO4-H2O is likely responsible for elevated N closest to the road, (3) N and particle growth are very sensitive to the condensation of semi-volatile organics (SVOCs), particle dry deposition, and the interaction between these processes. The results also indicate that, without the proper treatment of atmospheric boundary layer (i.e. its wind profile and turbulence quantities), the nucleation rate would be underestimated by a factor of 5 in the vehicle wake region due to overestimated mixing. Therefore, introducing ABL conditions to activity-based emission models may potentially improve their performance in estimating UFP traffic emissions.

  20. Emissions of trace gases and aerosols during the open combustion of biomass in the laboratory

    NASA Astrophysics Data System (ADS)

    McMeeking, Gavin R.; Kreidenweis, Sonia M.; Baker, Stephen; Carrico, Christian M.; Chow, Judith C.; Collett, Jeffrey L.; Hao, Wei Min; Holden, Amanda S.; Kirchstetter, Thomas W.; Malm, William C.; Moosmüller, Hans; Sullivan, Amy P.; Wold, Cyle E.

    2009-10-01

    We characterized the gas- and speciated aerosol-phase emissions from the open combustion of 33 different plant species during a series of 255 controlled laboratory burns during the Fire Laboratory at Missoula Experiments (FLAME). The plant species we tested were chosen to improve the existing database for U.S. domestic fuels: laboratory-based emission factors have not previously been reported for many commonly burned species that are frequently consumed by fires near populated regions and protected scenic areas. The plants we tested included the chaparral species chamise, manzanita, and ceanothus, and species common to the southeastern United States (common reed, hickory, kudzu, needlegrass rush, rhododendron, cord grass, sawgrass, titi, and wax myrtle). Fire-integrated emission factors for gas-phase CO2, CO, CH4, C2-4 hydrocarbons, NH3, SO2, NO, NO2, HNO3, and particle-phase organic carbon (OC), elemental carbon (EC), SO42-, NO3-, Cl-, Na+, K+, and NH4+ generally varied with both fuel type and with the fire-integrated modified combustion efficiency (MCE), a measure of the relative importance of flaming- and smoldering-phase combustion to the total emissions during the burn. Chaparral fuels tended to emit less particulate OC per unit mass of dry fuel than did other fuel types, whereas southeastern species had some of the largest observed emission factors for total fine particulate matter. Our measurements spanned a larger range of MCE than prior studies, and thus help to improve estimates of the variation of emissions with combustion conditions for individual fuels.

  1. Global top-down smoke-aerosol emissions estimation using satellite fire radiative power measurements

    NASA Astrophysics Data System (ADS)

    Ichoku, C.; Ellison, L.

    2014-07-01

    Fire emissions estimates have long been based on bottom-up approaches that are not only complex, but also fraught with compounding uncertainties. We present the development of a global gridded (1° × 1°) emission coefficients (Ce) product for smoke total particulate matter (TPM) based on a top-down approach using coincident measurements of fire radiative power (FRP) and aerosol optical thickness (AOT) from the Moderate-resolution Imaging Spectro-radiometer (MODIS) sensors aboard the Terra and Aqua satellites. This new Fire Energetics and Emissions Research version 1.0 (FEER.v1) Ce product has now been released to the community and can be obtained from http://feer.gsfc.nasa.gov/, along with the corresponding 1-to-1 mapping of their quality assurance (QA) flags that will enable the Ce values to be filtered by quality for use in various applications. The regional averages of Ce values for different ecosystem types were found to be in the ranges of 16-21 g MJ-1 for savanna and grasslands, 15-32 g MJ-1 for tropical forest, 9-12 g MJ-1 for North American boreal forest, and 18-26 g MJ-1 for Russian boreal forest, croplands and natural vegetation. The FEER.v1 Ce product was multiplied by time-integrated FRP data to calculate regional smoke TPM emissions, which were compared with equivalent emissions products from three existing inventories. FEER.v1 showed higher and more reasonable smoke TPM estimates than two other emissions inventories that are based on bottom-up approaches and already reported in the literature to be too low, but portrayed an overall reasonable agreement with another top-down approach. This suggests that top-down approaches may hold better promise and need to be further developed to accelerate the reduction of uncertainty associated with fire emissions estimation in air-quality and climate research and applications. Results of the analysis of FEER.v1 data for 2004-2011 show that 65-85 Tg yr-1 of

  2. Global Top-Down Smoke-Aerosol Emissions Estimation Using Satellite Fire Radiative Power Measurements

    NASA Technical Reports Server (NTRS)

    Ichoku, C.; Ellison, L.

    2014-01-01

    Fire emissions estimates have long been based on bottom-up approaches that are not only complex, but also fraught with compounding uncertainties. We present the development of a global gridded (1 deg ×1 deg) emission coefficients (Ce) product for smoke total particulate matter (TPM) based on a top-down approach using coincident measurements of fire radiative power (FRP) and aerosol optical thickness (AOT) from the Moderate-resolution Imaging Spectroradiometer (MODIS) sensors aboard the Terra and Aqua satellites. This new Fire Energetics and Emissions Research version 1.0 (FEER.v1) Ce product has now been released to the community and can be obtained from http://feer.gsfc. nasa.gov/, along with the corresponding 1-to-1 mapping of their quality assurance (QA) flags that will enable the Ce values to be filtered by quality for use in various applications. The regional averages of Ce values for different ecosystem types were found to be in the ranges of 16-21/gMJ-1 for savanna and grasslands, 15-32/gMJ-1 for tropical forest, 9-12/gMJ-1 for North American boreal forest, and 18- 26/MJ-1 for Russian boreal forest, croplands and natural vegetation. The FEER.v1 Ce product was multiplied by time-integrated FRP data to calculate regional smoke TPM emissions, which were compared with equivalent emissions products from three existing inventories. FEER.v1 showed higher and more reasonable smoke TPM estimates than two other emissions inventories that are based on bottom-up approaches and already reported in the literature to be too low, but portrayed an overall reasonable agreement with another top-down approach. This suggests that top-down approaches may hold better promise and need to be further developed to accelerate the reduction of uncertainty associated with fire emissions estimation in air-quality and climate research and applications. Results of the analysis of FEER.v1 data for 2004-2011 show that 65-85 Tg yr-1 of TPM is emitted globally from open biomass burning, with a

  3. Estimates of non-traditional secondary organic aerosols from aircraft SVOC and IVOC emissions using CMAQ

    NASA Astrophysics Data System (ADS)

    Woody, M. C.; West, J. J.; Jathar, S. H.; Robinson, A. L.; Arunachalam, S.

    2015-06-01

    Utilizing an aircraft-specific parameterization based on smog chamber data in the Community Multiscale Air Quality (CMAQ) model with the volatility basis set (VBS), we estimated contributions of non-traditional secondary organic aerosols (NTSOA) for aircraft emissions during landing and takeoff (LTO) activities at the Hartsfield-Jackson Atlanta International Airport. NTSOA, formed from the oxidation of semi-volatile and intermediate volatility organic compounds (S/IVOCs), is a heretofore unaccounted component of fine particulate matter (PM2.5) in most air quality models. We expanded a prerelease version of CMAQ with VBS implemented for the Carbon Bond 2005 (CB05) chemical mechanism to use the Statewide Air Pollution Research Center 2007 (SAPRC-07) chemical mechanism and added species representing aircraft S/IVOCs and corresponding NTSOA oxidation products. Results indicated that the maximum monthly average NTSOA contributions occurred at the airport and ranged from 2.4 ng m-3 (34 % from idle and 66 % from non-idle aircraft activities) in January to 9.1 ng m-3 (33 and 67 %) in July. This represents 1.7 % (of 140 ng m-3) in January and 7.4 % in July (of 122 ng m-3) of aircraft-attributable PM2.5 compared to 41.0-42.0 % from elemental carbon and 42.8-58.0 % from inorganic aerosols. As a percentage of PM2.5, impacts were higher downwind of the airport, where NTSOA averaged 4.6-17.9 % of aircraft-attributable PM2.5 and, considering alternative aging schemes, was as high as 24.0 % - thus indicating the increased contribution of aircraft-attributable SOA as a component of PM2.5. However, NTSOA contributions were generally low compared to smog chamber results, particularly at idle, due to the considerably lower ambient organic aerosol concentrations in CMAQ compared to those in the smog chamber experiments.

  4. Estimates of non-traditional secondary organic aerosols from aircraft SVOC and IVOC emissions using CMAQ

    NASA Astrophysics Data System (ADS)

    Woody, M. C.; West, J. J.; Jathar, S. H.; Robinson, A. L.; Arunachalam, S.

    2014-12-01

    Utilizing an aircraft-specific parameterization based on smog chamber data in the Community Multiscale Air Quality (CMAQ) model with the Volatility Basis Set (VBS), we estimated contributions of non-traditional secondary organic aerosols (NTSOA) for aircraft emissions during landing and takeoff (LTO) activities at the Hartsfield-Jackson Atlanta International Airport. NTSOA, formed from the oxidation of semi-volatile and intermediate volatility organic compounds (S/IVOCs), is a heretofore unaccounted component of fine particulate matter (PM2.5) in most air quality models. We expanded a prerelease version of CMAQ with VBS implemented for the Carbon Bond 2005 (CB05) chemical mechanism to use the Statewide Air Pollution Research Center 2007 (SAPRC-07) chemical mechanism, and added species representing aircraft S/IVOCs and corresponding NTSOA oxidation products. Results indicated the maximum monthly average NTSOA contributions occurred at the airport, and ranged from 2.4 ng m-3 (34% from idle and 66% from non-idle aircraft activities) in January to 9.1 ng m-3 (33 and 67%) in July. This represents 1.7% (of 140 ng m-3) in January and 7.4% in July (of 122 ng m-3) of aircraft-attributable PM2.5, compared to 41.0-42.0% from elemental carbon and 42.8-58.0% from inorganic aerosols. As a percentage of PM2.5, impacts were higher downwind of the airport, where NTSOA averaged 4.6-17.9% of aircraft-attributable PM2.5 and, considering alternative aging schemes, was high as 24.0% - thus indicating the increased contribution of aircraft-attributable SOA, as a component of PM2.5. However, NTSOA contributions were generally low compared to smog chamber results, particularly at idle, due to the considerably lower ambient organic aerosol concentrations in CMAQ, vs. those in the smog chamber experiments.

  5. Modeling of secondary organic aerosols from mobile sources in Mexico City

    NASA Astrophysics Data System (ADS)

    Zavala, M.; Lei, W.; Bei, N.; Li, G.; Tsimpidi, A. P.; Karydis, V. A.; Pandis, S.; Molina, L. T.

    2009-04-01

    Mobile sources are significant contributors of emissions of CO, NOx, hydrocarbons and particle matter (PM) that constitute critical precursors of ozone as well as secondary organic and inorganic particles that decisively impact the photochemical levels and aerosol loadings in the atmosphere. Currently there are large uncertainties in regional air quality models during the treatment of aerosol formation from aerosol precursors via the production of condensable organic gases. As a result, the modeling of the concentrations and properties of aerosols resulted from mobile emissions sources is an important challenge. In this study we compare aerosol simulations using the PM-CAMx air quality model linked to the SAPRC99 chemical mechanism with measured aerosol data obtained during the MILAGRO/MCMA-2006 field campaign in Mexico City. The PM-CAMx modeling framework is based on the volatility-basis approach: both primary and secondary organic components are assumed to be photochemically reactive and are logarithmically distributed in volatility bins. The distinction of the volatility properties of aerosols precursors is particularly important for diesel and gasoline emission sources due to their different organic carbon speciation emissions profiles. Using this volatility-basis technique, we will present results on the relative contributions from both gasoline and diesel vehicle fleet emission sources to the formation of secondary organic aerosols in an urban area.

  6. Updating sea spray aerosol emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2

    EPA Science Inventory

    Sea spray aerosols (SSAs) impact the particle mass concentration and gas-particle partitioning in coastal environments, with implications for human and ecosystem health. Model evaluations of SSA emissions have mainly focused on the global scale, but regional-scale evaluations are...

  7. Metrics for linking emissions of gases and aerosols to global precipitation changes

    NASA Astrophysics Data System (ADS)

    Shine, K. P.; Allan, R. P.; Collins, W. J.; Fuglestvedt, J. S.

    2015-04-01

    Recent advances in understanding have made it possible to relate global precipitation changes more directly to emissions of particular gases and aerosols that influence climate. Using these advances, a new index is developed here called the Global Precipitation-change Potential (GPP), which measures the precipitation change per unit mass of emissions. It is recognised that precipitation changes are predicted to be highly variable in size and sign between different regions, and ultimately climate change impacts will be more dependent on these regional changes. Nevertheless, the GPP presents a useful measure of the global-mean role of emissions of individual forcing agents. Results are presented for pulse (GPPP) and sustained (GPPS) emissions for selected long- and short-lived forcing agents (CO2, CH4, N2O, sulphate and black carbon - BC) using illustrative values of required parameters. The GPP can be used as a metric to compare the importance of emissions. This is akin to the global warming potential (GWP) and the global temperature-change potential (GTP) which are used to place emissions on a common scale. The GPP is further down the cause-effect chain from emissions to impacts than the GWP and GTP, and so provides an additional perspective. One key parameter needed for the GPP is the surface-atmosphere partitioning of radiative forcing. Few studies have presented results for this partitioning for different forcings, leading to more uncertainty in quantification of the GPP than the GWP or GTP. Using CO2 as references gas, the pulse and sustained GPP values for the non-CO2 species are larger than the corresponding GTP values, because the CO2 GPP is the sum of two quite strongly opposing terms. For BC emissions, the atmospheric forcing is sufficiently strong that the GPPS is opposite in sign to the GTPS. The choice of CO2 as a reference gas is problematic, especially for the GPPS at time horizons less than about 60 years, because the opposing terms make the CO2 GPPS

  8. The FLAME Deluge: organic aerosol emission ratios from combustion chamber experiments

    NASA Astrophysics Data System (ADS)

    Jolleys, Matthew; Coe, Hugh; McFiggans, Gordon; McMeeking, Gavin; Lee, Taehyoung; Sullivan, Amy; Kreidenweis, Sonia; Collett, Jeff

    2014-05-01

    A high level of variability has been identified amongst organic aerosol (OA) emission ratios (ER) from biomass burning (BB) under ambient conditions. However, it is difficult to assess the influences of potential drivers for this variability, given the wide range of conditions associated with wildfire measurements. Chamber experiments performed under controlled conditions provide a means of examining the effects of different fuel types and combustion conditions on OA emissions from biomass fuels. ERs have been characterised for 67 burns during the second Fire Laboratory at Missoula Experiment (FLAME II), involving 19 different species from 6 fuel types widely consumed in BB events in the US each year. Average normalised dOA/dCO ratios show a high degree of variability, both between and within different fuel types and species, typically exceeding variability between separate plumes in ambient measurements. Relationships with source conditions were found to be complex, with little consistent influence from fuel properties and combustion conditions for the entire range of experiments. No strong correlation across all fires was observed between dOA/dCO and modified combustion efficiency (MCE), which is used as an indicator of the proportional contributions of flaming and smouldering combustion phases throughout each burn. However, a negative correlation exists between dOA/dCO and MCE for some coniferous species, most notably Douglas fir, for which there is also an apparent influence from fuel moisture content. Significant contrasts were also identified between combustion emissions from different fuel components of additional coniferous species. Changes in fire efficiency were also shown to dramatically alter emissions for fires with very similar initial conditions. Although the relationship with MCE is variable between species, there is greater consistency with the level of oxygenation in OA. The ratio of the m/z 44 fragment to total OA mass concentration (f44) as

  9. Thermal Emission Spectrometer Results: Mars Atmospheric Thermal Structure and Aerosol Distribution

    NASA Technical Reports Server (NTRS)

    Smith, Michael D.; Pearl, John C.; Conrath, Barney J.; Christensen, Philip R.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Infrared spectra returned by the Thermal Emission Spectrometer (TES) are well suited for retrieval of the thermal structure and the distribution of aerosols in the Martian atmosphere. Combined nadir- and limb-viewing spectra allow global monitoring of the atmosphere up to 0.01 mbar (65 km). We report here on the atmospheric thermal structure and the distribution of aerosols as observed thus far during the mapping phase of the Mars Global Surveyor mission. Zonal and temporal mean cross sections are used to examine the seasonal evolution of atmospheric temperatures and zonal winds during a period extending from northern hemisphere mid-summer through vernal equinox (L(sub s) = 104-360 deg). Temperature maps at selected pressure levels provide a characterization of planetary-scale waves. Retrieved atmospheric infrared dust opacity maps show the formation and evolution of regional dust storms during southern hemisphere summer. Response of the atmospheric thermal structure to the changing dust loading is observed. Maps of water-ice clouds as viewed in the thermal infrared are presented along with seasonal trends of infrared water-ice opacity. Uses of these observations for diagnostic studies of the dynamics of the atmosphere are discussed.

  10. Emissions of trace gases and aerosols during the open combustion of biomass in the laboratory

    SciTech Connect

    McMeeking, Gavin R.; Kreidenweis, Sonia M.; Baker, Stephen; Carrico, Christian M.; Chow, Judith C.; Collett, Jr., Jeffrey L.; Hao, Wei Min; Holden, Amanda S.; Kirchstetter, Thomas W.; Malm, William C.; Moosmuller, Hans; Sullivan, Amy P.; Wold, Cyle E.

    2009-05-15

    We characterized the gas- and speciated aerosol-phase emissions from the open combustion of 33 different plant species during a series of 255 controlled laboratory burns during the Fire Laboratory at Missoula Experiments (FLAME). The plant species we tested were chosen to improve the existing database for U.S. domestic fuels: laboratory-based emission factors have not previously been reported for many commonly-burned species that are frequently consumed by fires near populated regions and protected scenic areas. The plants we tested included the chaparral species chamise, manzanita, and ceanothus, and species common to the southeastern US (common reed, hickory, kudzu, needlegrass rush, rhododendron, cord grass, sawgrass, titi, and wax myrtle). Fire-integrated emission factors for gas-phase CO{sub 2}, CO, CH{sub 4}, C{sub 2-4} hydrocarbons, NH{sub 3}, SO{sub 2}, NO, NO{sub 2}, HNO{sub 3} and particle-phase organic carbon (OC), elemental carbon (EC), SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, Cl{sup -}, Na{sup +}, K{sup +}, and NH{sub 4}{sup +} generally varied with both fuel type and with the fire-integrated modified combustion efficiency (MCE), a measure of the relative importance of flaming- and smoldering-phase combustion to the total emissions during the burn. Chaparral fuels tended to emit less particulate OC per unit mass of dry fuel than did other fuel types, whereas southeastern species had some of the largest observed EF for total fine particulate matter. Our measurements often spanned a larger range of MCE than prior studies, and thus help to improve estimates for individual fuels of the variation of emissions with combustion conditions.

  11. Reduced-form modeling of public health impacts of inorganic PM2.5 and precursor emissions

    NASA Astrophysics Data System (ADS)

    Heo, Jinhyok; Adams, Peter J.; Gao, H. Oliver

    2016-07-01

    It is challenging to estimate the public health costs of fine particulate matter (PM2.5) and its precursor emissions accurately and quickly for policy research because of their complex physical and chemical processes occurring over a large downwind area. We developed a method for building statistical regressions that estimate public health cost of emissions accurately like a state-of-the-art chemical transport model (CTM) but without its high computational cost. This method achieves detailed spatial resolution according to the location of the emission source, accounting for differences in the exposed population downwind. Using tagged CTM simulations, our method builds a large dataset of air quality public health costs from marginal emissions throughout the United States. Two methods were developed to describe exposed population, one that assumes a generic downwind plume concentration profile derived from CTM outputs and a simpler method that uses the size of population within certain distances as variables. Using the former method, we parameterized marginal public health cost [/t] and intake fraction [ppm] as a function of exposed population and key atmospheric variables. We derived models for elemental carbon, sulfur dioxide, nitrogen oxides, and ammonia. Compared to estimates calculated directly using CTM outputs, our models generally show mean fractional errors of only 10%-30% and up to 50% for NOx in some seasons, which are generally similar to or less than CTM's performance. Our results show that the public health costs of emissions can be efficiently parameterized for policy analyses based on state-of-the-art CTMs.

  12. Mineral dust aerosol from Saharan desert by means of atmospheric, emission, dispersion modelling

    NASA Astrophysics Data System (ADS)

    Guarnieri, F.; Calastrini, F.; Busillo, C.; Pasqui, M.; Becagli, S.; Lucarelli, F.; Calzolai, G.; Nava, S.; Udisti, R.

    2011-07-01

    The application of Numerical Prediction Models to mineral dust cycle is considered of prime importance for the investigation of aerosol and non-CO2 greenhouse gases contributions in climate variability and change. In this framework, a modelling system was developed in order to provide a regional characterization of Saharan dust intrusions over Mediterranean basin. The model chain is based on three different modules: the atmospheric model, the dust emission model and transport/deposition model. Numerical simulations for a selected case study, June 2006, were performed in order to evaluate the modelling system effectiveness. The comparison of the results obtained in such a case study shows a good agreement with those coming from GOCART model. Moreover a good correspondence was found in the comparison with in-situ measurements regarding some specific crustal markers in the PM10 fraction.

  13. 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

    EPA Science Inventory

    A suite of offline and real-time gas- and particle-phase measurements was deployed atLook 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) formatio...

  14. A Global view on the Emission of Swift Gamma-Ray Bursts: From Precursors to Extended Emission Tails and Late X-ray Flares

    NASA Astrophysics Data System (ADS)

    Liang, En-Wei; Zhang, Bing; Hu, You-Dong

    We present a joint analysis of the GRB data observed with the BAT and XRT on board Swift mission. Our results show that a precursor is observed in about 10 percents of the BAT GRBs, and most of them are of long-type GRBs. About half of the precursors triggers BAT to alert the GRBs. The triggered precursors are usually composed of some sharp pulses and non-triggered precursors are preferred to be some continuous flickers with almost a constant amplitude. There is no statistical difference of the photon indices between the triggered and non-triggered precursors, and their photon indices are also roughly consistent with that of the main bursts. The extended emision tails in the BAT band are usually observed in those GRBs that their main bursts are shorter than 2 seconds. These GRBs may be classified into the short-type GRBs. The EE tails are statistically softer than the emission in the main bursts and the corresponding X-ray flares are shown up in the XRT band. Taking the EE tails and late flares as evidence for late GRB central engine activity, we find that the lifetime of the GRB central engines of about 2/3 GRBs are much longer than T90. Our results indicate that the prompt gamma-ray phase may be only a short episode of the life times of the GRB central engines and what we have seen in the gamma-ray band may be only the tip of an iceberg of the GRB phenomenon. Future GRB alert instruments in the soft X-ray band may imporve our understanding on the activity of the GRB central engine in the early stage and the jet shock break-out as well as photosphere radaition.

  15. EVALUATION OF AEROSOL EMISSIONS DOWNSTREAM OF AN AMMONIA-BASED SO2 SCRUBBER

    SciTech Connect

    Dennis L. Laudal

    2002-04-01

    Depending on the size and type of boiler, the 1990 Clean Air Act Amendments required specific reductions in SO{sub 2} emissions from coal-fired electric utilities. To meet these requirements, SO{sub 2} reduction strategies have included installing scrubbing technology, switching to a more expensive low-sulfur coal, or purchasing SO{sub 2} allowances. It is expected that over the next 10 years there will be an increase in the price of low-sulfur coals, but that higher-sulfur coal costs will remain the same. Technologies must be strongly considered that allow the use of high-sulfur fuels while at the same time meeting current and future SO{sub 2} emission limits. One such technology is the ammonia based flue gas desulfurization (FGD) (NH{sub 3}-based FGD) system manufactured by Marsulex Environmental Technologies (MET). The MET scrubber is a patented NH{sub 3}-based FGD process that efficiently converts SO{sub 2} (>95%) into a fertilizer product, ammonium sulfate ([NH{sub 4}]{sub 2}SO{sub 4}). A point of concern for the MET technology, as well as other FGD systems, is the emission of sulfuric acid/SO{sub 3} aerosols that could result in increased opacity at the stack. This is a direct result of firing high-sulfur fuels that naturally generate more SO{sub 3} than do low-sulfur coals. SO{sub 3} is formed during the coal combustion process. SO{sub 3} is converted to gaseous H{sub 2}SO{sub 4} by homogeneous condensation, leading to a submicron acid fume that is very difficult to capture in a dry electrostatic precipitator (ESP). The condensed acid can also combine with the fly ash in the duct and scale the duct wall, potentially resulting in corrosion of both metallic and nonmetallic surfaces. Therefore, SO{sub 3} in flue gas can have a significant impact on the performance of coal-fired utility boilers, air heaters, and ESPs. In addition to corrosion problems, excess SO{sub 3} emissions can result in plume opacity problems. Thus the Energy & Environmental Research

  16. Emission of ent-kaurene, a diterpenoid hydrocarbon precursor for gibberellins, into the headspace from plants.

    PubMed

    Otsuka, Minoru; Kenmoku, Hiromichi; Ogawa, Mikihiro; Okada, Kazunori; Mitsuhashi, Wataru; Sassa, Takeshi; Kamiya, Yuji; Toyomasu, Tomonobu; Yamaguchi, Shinjiro

    2004-09-01

    ent-Kaurene is a tetracyclic hydrocarbon precursor for gibberellins (GAs) in plants and fungi. To address whether fungal GA biosynthesis enzymes function in plants, we generated transgenic Arabidopsis plants overexpressing ent-kaurene synthase (GfCPS/KS) from a GA-producing fungus Gibberella fujikuroi. GfCPS/KS catalyzes a two-step reaction corresponding to ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS) activities in plants. When GfCPS/KS was overexpressed and targeted to plastids, a range of GA-deficient phenotypes of the ga1-3 and ga2-1 mutants (defective in CPS and KS, respectively) were restored to wild type. Unexpectedly, the transgenic lines overproducing GfCPS/KS emitted the GA precursor ent-kaurene into the headspace besides its accumulation in the plant body. When co-cultivated with the ent-kaurene overproducers in a closed environment, the airborne ent-kaurene was able to fully complement the dwarf phenotype of ga1-3 and ga2-1 mutants, but not that of the ga3-1 mutant (defective in ent-kaurene oxidase). These results suggest that ent-kaurene may be efficiently metabolized into bioactive GAs in Arabidopsis when supplied as a volatile. We also provide evidence that ent-kaurene is released in the headspace of wild-type Chamaecyparis obtusa and Cryptomeria japonica plants, suggesting the occurrence of this hydrocarbon GA precursor as a volatile in nature.

  17. Effect of measurement protocol on organic aerosol measurements of exhaust emissions from gasoline and diesel vehicles

    NASA Astrophysics Data System (ADS)

    Kim, Youngseob; Sartelet, Karine; Seigneur, Christian; Charron, Aurélie; Besombes, Jean-Luc; Jaffrezo, Jean-Luc; Marchand, Nicolas; Polo, Lucie

    2016-09-01

    Exhaust emissions of semi-volatile organic compounds (SVOC) from passenger vehicles are usually estimated only for the particle phase via the total particulate matter measurements. However, they also need to be estimated for the gas phase, as they are semi-volatile. To better estimate SVOC emission factors of passenger vehicles, a measurement campaign using a chassis dynamometer was conducted with different instruments: (1) a constant volume sampling (CVS) system in which emissions were diluted with filtered air and sampling was performed on filters and polyurethane foams (PUF) and (2) a Dekati Fine Particle Sampler (FPS) in which emissions were diluted with purified air and sampled with on-line instruments (PTR-ToF-MS, HR-ToF-AMS, MAAP, CPC). Significant differences in the concentrations of organic carbon (OC) measured by the instruments are observed. The differences can be explained by sampling artefacts, differences between (1) the time elapsed during sampling (in the case of filter and PUF sampling) and (2) the time elapsed from emission to measurement (in the case of on-line instruments), which vary from a few seconds to 15 min, and by the different dilution factors. To relate elapsed times and measured concentrations of OC, the condensation of SVOC between the gas and particle phases is simulated with a dynamic aerosol model. The simulation results allow us to understand the relation between elapsed times and concentrations in the gas and particle phases. They indicate that the characteristic times to reach thermodynamic equilibrium between gas and particle phases may be as long as 8 min. Therefore, if the elapsed time is less than this characteristic time to reach equilibrium, gas-phase SVOC are not at equilibrium with the particle phase and a larger fraction of emitted SVOC will be in the gas phase than estimated by equilibrium theory, leading to an underestimation of emitted OC if only the particle phase is considered or if the gas-phase SVOC are estimated

  18. Characterizing particulate matter emissions from vehicles: chassis-dynamometer tests using a High-Resolution Aerosol Mass Spectrometer

    NASA Astrophysics Data System (ADS)

    Collier, S.; Zhang, Q.; Forestieri, S.; Kleeman, M.; Cappa, C. D.; Kuwayama, T.

    2012-12-01

    During September of 2011 a suite of real-time instruments was used to sample vehicle emissions at the California Air Resources Board Haagen-Schmidt facility in El Monte, CA. A representative fleet of 8 spark ignition gasoline vehicles, a diesel passenger vehicle, a gasoline direct-injection vehicle and an ultra-low emissions vehicle were tested on a chassis dynamometer. The emissions were sampled into the facility's standard CVS tunnel and diluted to atmospherically relevant levels (5-30 μg/m3) while controlling other factors such as relative humidity or background black carbon particulate loading concentrations. An Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-MS) was among the real-time instruments used and sampled vehicle emissions at 10 second time resolution in order to characterize the non-refractory organic and inorganic particulate matter (PM). PM composition and concentration were tracked throughout the cold start driving cycle which included periods of fast acceleration and high velocity cruise control, meant to recreate typical commuter driving behavior. Variations in inorganic and organic PM composition for a given vehicle throughout the driving cycle as well as for various vehicles with differing emissions loading were characterized. Differences in PM composition for a given vehicle whose emissions are being exposed to differing experimental conditions such as varying relative humidity will also be reported. In conjunction with measurements from a Multi Wavelength Photoacoustic Black Carbon Spectrometer (MWPA-BC) and real-time gas measurements from the CARB facility, we determine the real-time emission ratios of primary organic aerosols (POA) with respect to BC and common combustion gas phase pollutants and compared to different vehicle driving conditions. The results of these tests offer the vehicle emissions community a first time glimpse at the real-time behavior of vehicle PM emissions for a variety of conditions and

  19. Transformation of logwood combustion emissions in a smog chamber: formation of secondary organic aerosol and changes in the primary organic aerosol upon daytime and nighttime aging

    NASA Astrophysics Data System (ADS)

    Tiitta, Petri; Leskinen, Ari; Hao, Liqing; Yli-Pirilä, Pasi; Kortelainen, Miika; Grigonyte, Julija; Tissari, Jarkko; Lamberg, Heikki; Hartikainen, Anni; Kuuspalo, Kari; Kortelainen, Aki-Matti; Virtanen, Annele; Lehtinen, Kari E. J.; Komppula, Mika; Pieber, Simone; Prévôt, André S. H.; Onasch, Timothy B.; Worsnop, Douglas R.; Czech, Hendryk; Zimmermann, Ralf; Jokiniemi, Jorma; Sippula, Olli

    2016-10-01

    Organic aerosols (OA) derived from small-scale wood combustion emissions are not well represented by current emissions inventories and models, although they contribute substantially to the atmospheric particulate matter (PM) levels. In this work, a 29 m3 smog chamber in the ILMARI facility of the University of Eastern Finland was utilized to investigate the formation of secondary organic aerosol (SOA) from a small-scale modern masonry heater commonly used in northern Europe. Emissions were oxidatively aged in the smog chamber for a variety of dark (i.e., O3 and NO3) and UV (i.e., OH) conditions, with OH concentration levels of (0.5-5) × 106 molecules cm-3, achieving equivalent atmospheric aging of up to 18 h. An aerosol mass spectrometer characterized the direct OA emissions and the SOA formed from the combustion of three wood species (birch, beech and spruce) using two ignition processes (fast ignition with a VOC-to-NOx ratio of 3 and slow ignition with a ratio of 5).Dark and UV aging increased the SOA mass fraction with average SOA productions 2.0 times the initial OA mass loadings. SOA enhancement was found to be higher for the slow ignition compared with fast ignition conditions. Positive matrix factorization (PMF) was used to separate SOA, primary organic aerosol (POA) and their subgroups from the total OA mass spectra. PMF analysis identified two POA and three SOA factors that correlated with the three major oxidizers: ozone, the nitrate radical and the OH radical. Organonitrates (ONs) were observed to be emitted directly from the wood combustion and additionally formed during oxidation via NO3 radicals (dark aging), suggesting small-scale wood combustion may be a significant ON source. POA was oxidized after the ozone addition, forming aged POA, and after 7 h of aging more than 75 % of the original POA was transformed. This process may involve evaporation and homogeneous gas-phase oxidation as well as heterogeneous oxidation of particulate organic matter

  20. Seasonal differences in aerosol abundance and radiative forcing in months of contrasting emissions and rainfall over northern South Asia

    NASA Astrophysics Data System (ADS)

    Sadavarte, P.; Venkataraman, C.; Cherian, R.; Patil, N.; Madhavan, B. L.; Gupta, T.; Kulkarni, S.; Carmichael, G. R.; Adhikary, B.

    2016-01-01

    A modeling framework was used to examine gaps in understanding of seasonal and spatial heterogeneity in aerosol abundance and radiative forcing over northern South Asia, whose glimpses are revealed in observational studies. Regionally representative emissions were used in chemical transport model simulations at a spatial resolution of 60 × 60 km2, in April, July and September, chosen as months of contrasting emissions and rainfall. Modeled aerosol abundance in northern South Asia was predominantly found to be dust and carbonaceous in April, dust and sulfate in July and sulfate and carbonaceous in September. Anthropogenic aerosols arose from energy-use emissions (from industrial sources, residential biofuel cooking, brick kilns) in all months, additionally from field burning in April, and incursion from East Asia in September. In April, carbonaceous aerosols were abundant from open burning of agricultural fields even at high altitude locations (Godavari), and of forests in the eastern Gangetic Plain (Kolkata). Direct radiative forcing and heating rate, calculated from OPAC-SBDART, using modeled aerosol fields, and corrected by MODIS AOD observations, showed regionally uniform atmospheric forcing in April, compared to that in other months, influenced by both dust and black carbon abundance. A strong spatial heterogeneity of radiative forcing and heating rate was found, with factor of 2.5-3.5 lower atmospheric forcing over the Tibet plateau than that over the Ganga Plain and Northwest in July and September. However, even over the remote Tibet plateau, there was significant anthropogenic contribution to atmospheric forcing and heating rate (45% in Apr, 75% in Sep). Wind fields showed black carbon transport from south Asia in April and east Asia in September. Further evaluation of the transport of dust and anthropogenic emissions from various source regions and their deposition in the Himalaya and Tibet, is important in understanding regional air quality and climate

  1. Evidence for ships emissions in the Central Mediterranean Sea from aerosol chemical analyses at the island of Lampedusa

    NASA Astrophysics Data System (ADS)

    Becagli, S.; Sferlazzo, D. M.; Pace, G.; di Sarra, A.; Bommarito, C.; Calzolai, G.; Ghedini, C.; Lucarelli, F.; Meloni, D.; Monteleone, F.; Severi, M.; Traversi, R.; Udisti, R.

    2011-11-01

    Measurements of aerosol chemical composition made on the island of Lampedusa, south of the Sicily channel, during years 2004-2008, are used to identify the influence of ship emissions on aerosol particles in the Central Mediterranean. Evidence of ship emissions influence is found in 17% of the daily samples. Aerosol samples influenced by ships are characterized by elevated Ni and V soluble fraction (about 80% for aerosol from ships, versus about 40 % for crustal particles), high V and Ni to Si ratios, and values of Vsol>6 ng m-3. Back trajectories analysis on the selected events show that air masses prevalently come from the Sicily channel, where an intense ship traffic occurs. Vsol, Nisol, and non-sea salt SO42- (nssSO42-) show a marked seasonal behaviour, with an evident summer maximum. Such a pattern can be explained by several processes: (i) increased photochemical activity in summer, leading to a faster production of secondary aerosols, mainly nssSO42-, from the oxidation of SO2 in the ship plume; (ii) stronger marine boundary layer (MBL) stability in summer, leading to higher concentration of emitted compounds in the lowest atmospheric layers; (iii) more frequent meteorological conditions leading to consecutive days with trajectories from the Sicily channel in summer. A very intense event in spring 2008 was studied in detail, also using size segregated chemical measurements. These data show that elements arising from heavy oil combustion (V, Ni, Al, Fe) are distributed in the sub-micrometric fraction of the aerosol, and the metals are present as free metals, carbonates, oxides hydrates or labile complex with organic ligands, so that they are dissolved in mild condition (HNO3, pH1.5). Data suggest a characteristic nssSO42-/V ratio in the range 200-400 for ship emission aerosols in summer at Lampedusa. By using the value of 200 a lower limit for the ship contribution to total sulphates is estimated. Ship emissions account, as a summer average, at least for 1

  2. Simultaneous reductions in emissions of black carbon and co-emitted species will weaken the aerosol net cooling effect

    NASA Astrophysics Data System (ADS)

    Wang, Z. L.; Zhang, H.; Zhang, X. Y.

    2015-04-01

    Black carbon (BC), a distinct type of carbonaceous material formed from the incomplete combustion of fossil and biomass based fuels under certain conditions, can interact with solar radiation and clouds through its strong light-absorption ability, thereby warming the Earth's climate system. Some studies have even suggested that global warming could be slowed down in the short term by eliminating BC emission due to its short lifetime. In this study, we estimate the influence of removing some sources of BC and other co-emitted species on the aerosol radiative effect by using an aerosol-climate atmosphere-only model BCC_AGCM2.0.1_CUACE/Aero with prescribed sea surface temperature and sea ice cover, in combination with the aerosol emissions from the Representative Concentration Pathways (RCPs) scenarios. We find that the global annual mean aerosol net cooling effect at the top of the atmosphere (TOA) will be enhanced by 0.12 W m-2 compared with recent past year 2000 levels if the emissions of only BC are reduced to the level projected for 2100 based on the RCP2.6 scenario. This will be beneficial~for the mitigation of global warming. However, both aerosol negative direct and indirect radiative effects are weakened when BC and its co-emitted species (sulfur dioxide and organic carbon) are simultaneously reduced. Relative to year 2000 levels, the global annual mean aerosol net cooling effect at the TOA will be weakened by 1.7-2.0 W m-2 if the emissions of all these aerosols are decreased to the levels projected for 2100 in different ways based on the RCP2.6, RCP4.5, and RCP8.5 scenarios. Because there are no effective ways to remove the BC exclusively without influencing the other co-emitted components, our results therefore indicate that a reduction in BC emission can lead to an unexpected warming on the Earth's climate system in the future.

  3. VLF/LF EM emissions as main precursor of earthquakes and their searching possibilities for Georgian s/a region

    NASA Astrophysics Data System (ADS)

    Kachakhidze, Manana; Kachakhidze, Nino

    2016-04-01

    Authors of abstract have created work which offers model of earth electromagnetic emissions generation detected in the process of earthquake preparation on the basis of electrodynamics. The model gives qualitative explanation of a mechanism of generation of electromagnetic waves emitted in the earthquake preparation period. Besides, scheme of the methodology of earthquake forecasting is created based on avalanche-like unstable model of fault formation and an analogous model of electromagnetic contour, synthesis of which, is rather harmonious. According to the authors of the work electromagnetic emissions in radiodiapason is more universal and reliable than other anomalous variations of various geophysical phenomena in earthquake preparation period; Besides, VLF/LF electromagnetic emissions might be declared as the main precursor of earthquake because it might turn out very useful with the view of prediction of large (M ≥5) inland earthquakes and to govern processes going on in lithosphere-atmosphere - ionosphere coupling (LAIC) system. Since the other geophysical phenomena, which may accompany earthquake preparation process and expose themselves several months, weeks or days prior to earthquakes are less informative with the view of earthquake forecasting, it is admissible to consider them as earthquake indicators. Physical mechanisms of mentioned phenomena are explained on the basis of the model of generation of electromagnetic emissions detected before earthquake, where a process of earthquake preparation and its realization are considered taking into account distributed and conservative systems properties. Up to these days electromagnetic emissions detection network did not exist in Georgia. European colleagues helped us (Prof. Dr. PF Biagi, Prof. Dr. Aydın BÜYÜKSARAÇ) and made possible the installation of a receiver. We are going to develop network and put our share in searching of earthquakes problem. Participation in conference is supported by financial

  4. An experimental study quantifying pulmonary ventilation on inhalation of aerosol under steady and episodic emission.

    PubMed

    Poon, Carmen K M; Lai, Alvin C K

    2011-09-15

    Estimating inhalation dose accurately under realistic conditions can enhance the accuracy of risk assessment. Conventional methods to quantify aerosol concentration that susceptible victims in contaminated environments are exposed to use real time particle counters to measure concentrations in environments without occupancy. Breathing-induced airflow interacts and influences concentration around nostrils or mouth and alter the ultimate exposure. This subject has not yet been systematically studied, particularly under transient emission. In this work, an experimental facility comprising two manikins was designed and fabricated. One of them mimicked realistic breathing, acting as a susceptible victim. Both steady and episodic emissions were generated in an air-conditioned environmental chamber in which two different ventilation schemes were tested. The scaled-dose of the victim under different expiratory velocities and pulmonary ventilation was measured. Inferring from results obtained from comprehensive tests, it can be concluded that breathing has very significant influence on the ultimate dose compared with that without breathing. Majority of results show that breathing reduces inhalation quantity and the reduction magnitude increases with breathing rate. This is attributed to the fact that the exhalation process plays a more significant role in reducing the dose level than the enhanced effect during inhalation period. The higher the breathing rate, the sharper the decline of the resultant concentration would be leading to lower dose. Nevertheless, under low pulmonary ventilation, results show that breathing increases dose marginally. Results also reveals that ventilation scheme also affects the exposure.

  5. Development of a United States-Mexico Emissions Inventory for the Big Bend Regional Aerosol and Visibility Observational (BRAVO) Study.

    PubMed

    Kuhns, Hampden; Knipping, Eladio M; Vukovich, Jeffrey M

    2005-05-01

    The Big Bend Regional Aerosol and Visibility Observational (BRAVO) Study was commissioned to investigate the sources of haze at Big Bend National Park in southwest Texas. The modeling domain of the BRAVO Study includes most of the continental United States and Mexico. The BRAVO emissions inventory was constructed from the 1999 National Emission Inventory for the United States, modified to include finer-resolution data for Texas and 13 U.S. states in close proximity. The first regional-scale Mexican emissions inventory designed for air-quality modeling applications was developed for 10 northern Mexican states, the Tula Industrial Park in the state of Hidalgo, and the Popocatépetl volcano in the state of Puebla. Emissions data were compiled from numerous sources, including the U.S. Environmental Protection Agency (EPA), the Texas Natural Resources Conservation Commission (now Texas Commission on Environmental Quality), the Eastern Research Group, the Minerals Management Service, the Instituto Nacional de Ecología, and the Instituto Nacional de Estadistica Geografía y Informática. The inventory includes emissions for CO, nitrogen oxides, sulfur dioxide, volatile organic compounds (VOCs), ammonia, particulate matter (PM) < 10 microm in aerodynamic diameter, and PM < 2.5 microm in aerodynamic diameter. Wind-blown dust and biomass burning were not included in the inventory, although high concentrations of dust and organic PM attributed to biomass burning have been observed at Big Bend National Park. The SMOKE modeling system was used to generate gridded emissions fields for use with the Regional Modeling System for Aerosols and Deposition (REMSAD) and the Community Multiscale Air Quality model modified with the Model of Aerosol Dynamics, Reaction, Ionization and Dissolution (CMAQ-MADRID). The compilation of the inventory, supporting model input data, and issues encountered during the development of the inventory are documented. A comparison of the BRAVO emissions

  6. Fine urban and precursor emissions control for diesel urban transit buses.

    PubMed

    Lanni, Thomas

    2003-01-01

    Particulate emission from diesel engines is one of the most important pollutants in urban areas. As a result, particulate emission control from urban bus diesel engines using particle filter technology is being evaluated at several locations in the US. A project entitled "Clean Diesel Air Quality Demonstration Program" has been initiated by the New York City Metropolitan Transit Authority (MTA) under the supervision of New York State Department of Environmental Conservation and with active participation from Johnson Matthey, Corning, Equilon, Environment Canada and RAD Energy. Under this program, several MTA transit buses with DDC Series 50 engines were equipped with Continuously Regenerating Technology (CRTTM) particulate filter systems and have been operated with ultra low sulfur diesel (<30 ppm S) in transit service in Manhattan since February 2000. These buses were evaluated over a 9-month period for durability and maintainability of the particulate filter. In addition, an extensive emissions testing program was carried out using transient cycles on a chassis dynamometer to evaluate the emissions reductions obtained with the particle filter. In this paper, the emissions testing data from the Clean Diesel Air Quality Demonstration Program are discussed in detail.

  7. Using Thermal-Optical Analysis to Examine the OC-EC Split that Characterizes Ambient and Source Emissions Aerosols

    NASA Astrophysics Data System (ADS)

    Khan, B.; Hays, M. D.; Geron, C.; Jetter, J.

    2010-12-01

    Thermal-optical analysis (TOA) is typically used to measure OC-EC (organic carbon-elemental carbon) ratio in atmospheric aerosols. The present study utilizes a single dual-optics carbon aerosol analyzer to examine the effects of temperature-programming and optics on the OC-EC ratios. The OC-EC ratios for a variety of atmospheric and source emissions aerosols were measured using a National Institute of Occupational Safety and Health method (NIOSH 5040), the Interagency Monitoring of Protected Visual Environments method (IMPROVE), and a modified NIOSH 5040 method (referred in this paper as NIST-EPA). Use of the dual-optics instrument allowed simultaneous monitoring of the reflectance (TOR) and transmission (TOT) during each thermal protocol. Results showed no statistical difference between NIST-EPA and NIOSH OC-EC ratios for residential cookstove emissions and for an urban aerosol collected in Nairobi, Kenya. However, the OC-EC ratios for diesel exhaust (NIST [TOT and TOR]) and for a denuded rural North Carolina forest aerosol (NIST [TOT]) were significantly greater than the corresponding NIOSH values. Significantly lower IMPROVE (TOT and TOR) OC-EC ratios, compared to NIST-EPA and NIOSH, may be ascribed to the lower temperature protocol of this method. The ratio of TOT-to-TOR for the OC-EC ratio ranged between 1.37 - 1.71 (residential cookstoves), 1.05 - 1.24 (diesel exhaust), 1.63 - 2.23 (rural), and 0.80 - 1.12 (urban) for the three methods. Aerosols containing components susceptible to charring (such as water soluble organic compounds typical of rural and cookstove aerosols) tend to show the higher OC-EC variability among the methods when compared to diesel-impacted aerosols, which showed little to no detectable pyrolyzed carbon (PyC). Different sample types, due to their various chemical compositions, behave differently under dissimilar thermal and optical conditions, such that the search for a “universal” thermal-optical method for all sample types remain

  8. Improved attribution of climate forcing to emissions.

    PubMed

    Shindell, Drew T; Faluvegi, Greg; Koch, Dorothy M; Schmidt, Gavin A; Unger, Nadine; Bauer, Susanne E

    2009-10-30

    Evaluating multicomponent climate change mitigation strategies requires knowledge of the diverse direct and indirect effects of emissions. Methane, ozone, and aerosols are linked through atmospheric chemistry so that emissions of a single pollutant can affect several species. We calculated atmospheric composition changes, historical radiative forcing, and forcing per unit of emission due to aerosol and tropospheric ozone precursor emissions in a coupled composition-climate model. We found that gas-aerosol interactions substantially alter the relative importance of the various emissions. In particular, methane emissions have a larger impact than that used in current carbon-trading schemes or in the Kyoto Protocol. Thus, assessments of multigas mitigation policies, as well as any separate efforts to mitigate warming from short-lived pollutants, should include gas-aerosol interactions.

  9. Unspeciated Organic Emissions From Combustion Sources And Their Influence On The Secondary Organic Aerosol Budget In The United States

    NASA Astrophysics Data System (ADS)

    Jathar, S.; Gordon, T.; Hennigan, C. J.; Pye, H. O.; Donahue, N. M.; Adams, P. J.; Robinson, A. L.

    2012-12-01

    Combustion sources are a major source of organic emissions and therefore a potentially important source for secondary organic aerosol (SOA) formation in the atmosphere. Although speciated organic emissions from combustion sources are considered in models to form SOA, a large fraction of the organics are unspeciated. In this work, we analyze data from numerous smog chamber experiments, which photo-oxidized dilute emissions from different combustion sources (on-road gasoline vehicles, aircraft, on-road diesel vehicles, wood burning and open biomass burning), to determine the contribution that unspeciated emissions make to SOA formation. An SOA model based on speciated organics is able to explain, on average, 8-31% of the SOA measured in the experiments. We hypothesize that the remainder results from the gas-phase oxidation of unspeciated emissions, which account on average for 25-75% of the non-methane organic gas (NMOG) emissions. Using the SOA data, we develop, for the first time, source-specific parameterizations to model SOA from unspeciated emissions; all sources seem to have median SOA yields similar to large n-alkanes (C12+). To assess the influence of unspeciated emissions on SOA formation regionally, we use the parameterization to predict SOA production in the United States. Using emissions data collected during the smog chamber experiments and data available in literature, we build a gross inventory for unspeciated emissions in the United States. We discover that unspeciated organics might be included in the current generation of SOA models but misallocated in terms of its SOA potential. The top six combustion sources (on- and off-road gasoline, on- and off-road diesel, open biomass and wood burning) emit 2.61 Tg yr-1 of unspeciated emissions (20% of US anthropogenic VOC emissions from combustion sources) and are estimated to form a minimum of 0.68 Tg yr-1 of SOA; the estimate is a third of the biogenic SOA produced in the US. We predict that accounting for

  10. Warming-induced increase in aerosol number concentration likely to moderate climate change

    NASA Astrophysics Data System (ADS)

    Paasonen, Pauli; Asmi, Ari; Petäjä, Tuukka; Kajos, Maija K.; Äijälä, Mikko; Junninen, Heikki; Holst, Thomas; Abbatt, Jonathan P. D.; Arneth, Almut; Birmili, Wolfram; van der Gon, Hugo Denier; Hamed, Amar; Hoffer, András; Laakso, Lauri; Laaksonen, Ari; Richard Leaitch, W.; Plass-Dülmer, Christian; Pryor, Sara C.; Räisänen, Petri; Swietlicki, Erik; Wiedensohler, Alfred; Worsnop, Douglas R.; Kerminen, Veli-Matti; Kulmala, Markku

    2013-06-01

    Atmospheric aerosol particles influence the climate system directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. Apart from black carbon aerosol, aerosols cause a negative radiative forcing at the top of the atmosphere and substantially mitigate the warming caused by greenhouse gases. In the future, tightening of controls on anthropogenic aerosol and precursor vapour emissions to achieve higher air quality may weaken this beneficial effect. Natural aerosols, too, might affect future warming. Here we analyse long-term observations of concentrations and compositions of aerosol particles and their biogenic precursor vapours in continental mid- and high-latitude environments. We use measurements of particle number size distribution together with boundary layer heights derived from reanalysis data to show that the boundary layer burden of cloud condensation nuclei increases exponentially with temperature. Our results confirm a negative feedback mechanism between the continental biosphere, aerosols and climate: aerosol cooling effects are strengthened by rising biogenic organic vapour emissions in response to warming, which in turn enhance condensation on particles and their growth to the size of cloud condensation nuclei. This natural growth mechanism produces roughly 50% of particles at the size of cloud condensation nuclei across Europe. We conclude that biosphere-atmosphere interactions are crucial for aerosol climate effects and can significantly influence the effects of anthropogenic aerosol emission controls, both on climate and air quality.

  11. UNITED STATES LAND USE INVENTORY FOR ESTIMATING BIOGENIC OZONE PRECURSOR EMISSIONS

    EPA Science Inventory

    The U.S. Geological Survey's (USGS) Earth Resources Observation System (EROS) Data Center's (EDC) 1-km classified land cover data are combined with other land use data using a Geographic Information System (GIS) to create the Biogenic Emissions Landcover Database (BELD). The land...

  12. Measurements of Volatile Organic Compounds (VOCs) from Biomass Combustion - Emission Ratios, OH Reactivities and SOA Precursors

    NASA Astrophysics Data System (ADS)

    Kuster, W. C.; Gilman, J. B.; Goldan, P. D.; Warneke, C.; Degouw, J.; Veres, P. R.; Burling, I. R.; Yokelson, R. J.

    2009-12-01

    Multiple instruments including a gas chromatograph/mass spectrometer (GC/MS), a proton transfer reaction mass spectrometer (PTR-MS), a proton ion trap mass spectrometer (PIT-MS), a negative-ion proton-transfer chemical-ionization mass spectrometer (NI-PT-CIMS) and a Fourier-transform infrared spectrometer (FTIR) acquired data from 77 burns of various biomass fuels conducted at the U.S. Department of Agriculture (USDA) Forest Sciences Laboratory (FSL) in Missoula, MT in February 2009. We compare VOC measurements of oxygenates, aromatics and biogenics from the various instruments as well as from the various fuel types collected in southeastern and southwestern regions of the United States. The relative contribution of the combustion species to the total reactivity with the OH radical is calculated and compared to ambient air reactivity in various locations. Total reactivity for measured species in these fires occasionally exceeded 1000 sec-1 with the majority of this reactivity due to alkenes. In addition, we investigate the relative contribution of the combustion species to the potential for secondary organic aerosol (SOA) formation. Measurements of several compounds not previously reported in various urban ambient air measurement campaigns such as pyrazole (C3H4N2), pyrrole (C4H5N), benzofuran (C8H6O) and 2-furanaldehyde (C5H4O2), which are highly reactive with OH, will be presented.

  13. Highly efficient photocatalytic TiO2 coatings deposited by open air atmospheric pressure plasma jet with aerosolized TTIP precursor

    NASA Astrophysics Data System (ADS)

    Fakhouri, H.; Ben Salem, D.; Carton, O.; Pulpytel, J.; Arefi-Khonsari, F.

    2014-07-01

    A simple method to deposit photocatalytic TiO2 coatings, at a high rate (20-40 µm s-1), and with a high porosity, is reported in this paper. This method, which allows the treatment of membranes (with an 800 nm pore size), is based on the introduction of a liquid precursor sprayed into an open-air atmospheric pressure plasma jet (APPJ). The photocatalytic activity of the TiO2 thin films prepared by APPJ have been compared with our best N-doped TiO2 thin films, deposited by reactive radio frequency (RF) magnetron sputtering, previously reported in the literature. The morphology, chemical composition, photoelectrochemical, and photocatalytic properties of the coatings have been studied in this paper. Significant control of the porosity and crystallinity was achieved by varying the deposition parameters and the annealing temperature. Under optimized conditions, the TiO2 coatings deposited by APPJ are characterized by a higher photocatalytic activity as compared to the optimized thin films deposited by RF sputtering. This difference can be explained by the higher specific surface of the APPJ coatings. Finally, the most interesting characteristic of this APPJ-liquid spray process is its capacity to treat membranes without blocking the pores, and to produce photocatalytic membranes which can efficiently combine filtration and photocatalysis for water treatment.

  14. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia since the turn of the century.

    PubMed

    O'Sullivan, M; Rap, A; Reddington, C L; Spracklen, D V; Gloor, M; Buermann, W

    2016-08-16

    The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998-2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen-carbon interactions.

  15. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia since the turn of the century

    NASA Astrophysics Data System (ADS)

    O'Sullivan, M.; Rap, A.; Reddington, C. L.; Spracklen, D. V.; Gloor, M.; Buermann, W.

    2016-08-01

    The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998-2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen-carbon interactions.

  16. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia since the turn of the century

    PubMed Central

    Rap, A.; Reddington, C. L.; Spracklen, D. V.; Gloor, M.; Buermann, W.

    2016-01-01

    Abstract The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998–2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen‐carbon interactions. PMID:27773953

  17. Comparative analysis of urban atmospheric aerosol by particle-induced X-ray emission (PIXE), proton elastic scattering analysis (PESA), and aerosol mass spectrometry (AMS).

    PubMed

    Johnson, K S; Laskin, A; Jimenez, J L; Shutthanandan, V; Molina, L T; Salcedo, D; Dzepina, K; Molina, M J

    2008-09-01

    A multifaceted approach to atmospheric aerosol analysis is often desirable in field studies where an understanding of technical comparability among different measurement techniques is essential. Herein, we report quantitative intercomparisons of particle-induced X-ray emission (PIXE) and proton elastic scattering analysis (PESA), performed of fline under a vacuum, with analysis by aerosol mass spectrometry (AMS) carried out in real-time during the MCMA-2003 Field Campaign in the Mexico City Metropolitan Area. Good agreement was observed for mass concentrations of PIXE-measured sulfur (assuming it was dominated by SO4(2-)) and AMS-measured sulfate during most of the campaign. PESA-measured hydrogen mass was separated into sulfate H and organic H mass fractions, assuming the only major contributions were (NH4)2SO4 and organic compounds. Comparison of the organic H mass with AMS organic aerosol measurements indicates that about 75% of the mass of these species evaporated under a vacuum. However approximately 25% of the organics does remain under a vacuum, which is only possible with low-vapor-pressure compounds, and which supports the presence of high-molecular-weight or highly oxidized organics consistent with atmospheric aging. Approximately 10% of the chloride detected by AMS was measured by PIXE, possibly in the form of metal-chloride complexes, while the majority of Cl was likely present as more volatile species including NH4Cl. This is the first comparison of PIXE/PESA and AMS and, to our knowledge, also the first report of PESA hydrogen measurements for urban organic aerosols.

  18. Unspeciated organic emissions from combustion sources and their influence on the secondary organic aerosol budget in the United States.

    PubMed

    Jathar, Shantanu H; Gordon, Timothy D; Hennigan, Christopher J; Pye, Havala O T; Pouliot, George; Adams, Peter J; Donahue, Neil M; Robinson, Allen L

    2014-07-22

    Secondary organic aerosol (SOA) formed from the atmospheric oxidation of nonmethane organic gases (NMOG) is a major contributor to atmospheric aerosol mass. Emissions and smog chamber experiments were performed to investigate SOA formation from gasoline vehicles, diesel vehicles, and biomass burning. About 10-20% of NMOG emissions from these major combustion sources are not routinely speciated and therefore are currently misclassified in emission inventories and chemical transport models. The smog chamber data demonstrate that this misclassification biases model predictions of SOA production low because the unspeciated NMOG produce more SOA per unit mass than the speciated NMOG. We present new source-specific SOA yield parameterizations for these unspeciated emissions. These parameterizations and associated source profiles are designed for implementation in chemical transport models. Box model calculations using these new parameterizations predict that NMOG emissions from the top six combustion sources form 0.7 Tg y(-1) of first-generation SOA in the United States, almost 90% of which is from biomass burning and gasoline vehicles. About 85% of this SOA comes from unspeciated NMOG, demonstrating that chemical transport models need improved treatment of combustion emissions to accurately predict ambient SOA concentrations.

  19. Impact of Emissions and Long-Range Transport on Multi-Decadal Aerosol Trends: Implications for Air Quality and Climate

    NASA Technical Reports Server (NTRS)

    Chin, Mian

    2012-01-01

    We present a global model analysis of the impact of long-range transport and anthropogenic emissions on the aerosol trends in the major pollution regions in the northern hemisphere and in the Arctic in the past three decades. We will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model to analyze the multi-spatial and temporal scale data, including observations from Terra, Aqua, and CALIPSO satellites and from the long-term surface monitoring stations. We will analyze the source attribution (SA) and source-receptor (SR) relationships in North America, Europe, East Asia, South Asia, and the Arctic at the surface and free troposphere and establish the quantitative linkages between emissions from different source regions. We will discuss the implications for regional air quality and climate change.

  20. Atmospheric aerosol monitoring and characterization: An emission control strategy to protect tropical forests

    NASA Astrophysics Data System (ADS)

    Mateus, V. L.; do Valles, T. V.; de Oliveira, T. B.; de Almeida, A. C.; Maia, L. F. P. G.; Saint'Pierre, T. D.; Gioda, A.

    2013-12-01

    Human activity represents one of the most harmful activities for biodiversity. Population growth has caused increasing interferences in natural areas suffering agriculture or urbanization. As a consequence, tropical forests are at risk, since they shelter more than half of the global biodiversity. In this context, protected areas are indeed important to preserve natural populations as well as threatened habitats. Aerosol samples were collected in two protected areas in Rio de Janeiro, Brazil, in order to quantify water-soluble species and evaluate anthropogenic influences considering secondary aerosol formation and organic compounds. Samplings were conducted at the National Park of Serra dos Orgãos (Parnaso) and the National Forest Mario Xavier (Flonamax) during 24 h every six days using a high-volume sampler from July 2010 to June 2012 (PM10) and from July 2011 to August 2012 (TSP), respectively. The aerosol mass was determined by Gravimetry. The water-soluble ionic composition (WSIC) was obtained by Ion Chromatography in order to determine the major anions (Br-, Cl-, F-, NO2-, NO3-, PO43-, SO42-) and cations (Li+, Ca2+, K+, Mg2+, Na+, NH4+); total water-soluble carbon (TWSC), water-soluble organic carbon (WSOC) were determined by a TOC analyzer and the elements were determined by Inductively Coupled Plasma Optical Emission Spectrometry. PM10 average concentrations ranged from 11.1 to 67.6 μg m-3 and TSP from 5.7 to 242.6 μg m-3. Regarding the ions, the highest cation concentration was measured for Na+ at both Parnaso and Flonamax sites, respectively, 2.9 and 6.1 μg m-3. Both sites are near to the coast, justifying these results. On the other hand, SO42- was the predominant anion measured at both sites with average concentrations ranged from 2.3 to 2.7 μg m-3. Around 50% of sulphate had a non-marine origin in the former site, while in the latter the percentage was of circa 40%. The correlation between NO3- and nss-SO42- was much stronger at Parnaso (r = 0

  1. Brown carbon aerosols from burning of boreal peatlands: microphysical properties, emission factors, and implications for direct radiative forcing

    NASA Astrophysics Data System (ADS)

    Chakrabarty, Rajan K.; Gyawali, Madhu; Yatavelli, Reddy L. N.; Pandey, Apoorva; Watts, Adam C.; Knue, Joseph; Chen, Lung-Wen A.; Pattison, Robert R.; Tsibart, Anna; Samburova, Vera; Moosmüller, Hans

    2016-03-01

    The surface air warming over the Arctic has been almost twice as much as the global average in recent decades. In this region, unprecedented amounts of smoldering peat fires have been identified as a major emission source of climate-warming agents. While much is known about greenhouse gas emissions from these fires, there is a knowledge gap on the nature of particulate emissions and their potential role in atmospheric warming. Here, we show that aerosols emitted from burning of Alaskan and Siberian peatlands are predominantly brown carbon (BrC) - a class of visible light-absorbing organic carbon (OC) - with a negligible amount of black carbon content. The mean fuel-based emission factors for OC aerosols ranged from 3.8 to 16.6 g kg-1. Their mass absorption efficiencies were in the range of 0.2-0.8 m2 g-1 at 405 nm (violet) and dropped sharply to 0.03-0.07 m2 g-1 at 532 nm (green), characterized by a mean Ångström exponent of ≈ 9. Electron microscopy images of the particles revealed their morphologies to be either single sphere or agglomerated "tar balls". The shortwave top-of-atmosphere aerosol radiative forcing per unit optical depth under clear-sky conditions was estimated as a function of surface albedo. Only over bright surfaces with albedo greater than 0.6, such as snow cover and low-level clouds, the emitted aerosols could result in a net warming (positive forcing) of the atmosphere.

  2. Emissions of Black Carbon, Organic, and Inorganic Aerosols From Biomass Burning in North America and Asia in 2008

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Matsui, H.; Moteki, N.; Sahu, L.; Takegawa, N.; Kajino, M.; Zhao, Y.; Cubison, M. J.; Jimenez, J. L.; Vay, S.; Diskin, G. S.; Anderson, B.; Wisthaler, A.; Mikoviny, T.; Fuelberg, H. E.; Blake, D. R.; Huey, G.; Weinheimer, A. J.; Knapp, D. J.; Brune, W. H.

    2011-01-01

    Reliable assessment of the impact of aerosols emitted from boreal forest fires on the Arctic climate necessitates improved understanding of emissions and the microphysical properties of carbonaceous (black carbon (BC) and organic aerosols (OA)) and inorganic aerosols. The size distributions of BC were measured by an SP2 based on the laser-induced incandescence technique on board the DC-8 aircraft during the NASA ARCTAS campaign. Aircraft sampling was made in fresh plumes strongly impacted by wildfires in North America (Canada and California) in summer 2008 and in those transported from Asia (Siberia in Russia and Kazakhstan) in spring 2008. We extracted biomass burning plumes using particle and tracer (CO, CH3CN, and CH2Cl2) data. OA constituted the dominant fraction of aerosols mass in the submicron range. The large majority of the emitted particles did not contain BC. We related the combustion phase of the fire as represented by the modified combustion efficiency (MCE) to the emission ratios between BC and other species. In particular, we derived the average emission ratios of BC/CO = 2.3 +/- 2.2 and 8.5 +/- 5.4 ng/cu m/ppbv for BB in North America and Asia, respectively. The difference in the BC/CO emission ratios is likely due to the difference in MCE. The count median diameters and geometric standard deviations of the lognormal size distribution of BC in the BB plumes were 136-141 nm and 1.32-1.36, respectively, and depended little on MCE. These BC particles were thickly coated, with shell/core ratios of 1.3-1.6. These parameters can be used directly for improving model estimates of the impact of BB in the Arctic.

  3. The effect of large anthropogenic particulate emissions on atmospheric aerosols, deposition and bioindicators in the eastern Gulf of Finland region.

    PubMed

    Jalkanen, L; Mäkinen, A; Häsänen, E; Juhanoja, J

    2000-10-30

    The effect of the emissions from large oil shale fuelled power plants and a cement factory in Estonia on the elemental concentration of atmospheric aerosols, deposition, elemental composition of mosses and ecological effects on mosses, lichens and pine trees in the eastern Gulf of Finland region has been studied. In addition to chemical analysis, fly ash, moss and aerosol samples were analysed by a scanning electron microscope with an energy dispersive X-ray spectrometer (SEM/EDS). The massive particulate calcium emissions, approximately 60 kton/year (1992), is clearly observed in the aerosols, deposition and mosses. The calcium deposition is largest next to the Russian border downwind from the power plants and in south-eastern part of Finland. This deposition has decreased due to the application of dust removal systems at the particulate emission sources. At the Virolahti EMEP station approximately 140 km north from the emission sources, elevated elemental atmospheric aerosol concentrations are observed for Al, Ca, Fe, K and Si and during episodes many trace elements, such as As, Br, Mo, Ni, Pb and V. The acidification of the soil is negligible because of the high content of basic cations in the deposition. Visible symptoms on pine trees are negligible. However, in moss samples close to the power plants, up to 25% of the leaf surface was covered by particles. Many epiphytic lichen species do not tolerate basic stemflow and on the other hand most species are also very sensitive for the SO2 content in air. Consequently a large lichen desert is found in an area of 2500 km2 in the vicinity of the power plants with only one out of the investigated 12 species growing.

  4. Linking biogenic hydrocarbons to biogenic aerosol in the Borneo rainforest

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Alfarra, M. R.; Robinson, N.; Ward, M. W.; Lewis, A. C.; McFiggans, G. B.; Coe, H.; Allan, J. D.

    2013-07-01

    Emissions of biogenic volatile organic compounds are though to contribute significantly to secondary organic aerosol formation in the tropics, but understanding the process of these transformations has proved difficult, due to the complexity of the chemistry involved and very low concentrations. Aerosols from above a South East Asian tropical rainforest in Borneo were characterised using liquid chromatography-ion trap mass spectrometry, high resolution aerosol mass spectrometry and fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) techniques. Oxygenated compounds were identified in ambient organic aerosol that could be directly traced back to isoprene, monoterpenes and sesquiterpene emissions, by combining field data on chemical structures with mass spectral data generated from synthetically produced products created in a simulation chamber. Eighteen oxygenated species of biogenic origin were identified in the rainforest aerosol from the precursors isoprene, α-pinene, limonene, α-terpinene and β-caryophyllene. The observations provide the unambiguous field detection of monoterpene and sesquiterpene oxidation products in SOA above a pristine tropical rainforest. The presence of 2-methyltetrol organosulfates and an associated sulfated dimer provides direct evidence that isoprene in the presence of sulfate aerosol can make a contribution to biogenic organic aerosol above tropical forests. High-resolution mass spectrometry indicates that sulfur can also be incorporated into oxidation products arising from monoterpene precursors in tropical aerosol.

  5. Linking biogenic hydrocarbons to biogenic aerosol in the Borneo rainforest

    NASA Astrophysics Data System (ADS)

    Hamilton, J. F.; Alfarra, M. R.; Robinson, N.; Ward, M. W.; Lewis, A. C.; McFiggans, G. B.; Coe, H.; Allan, J. D.

    2013-11-01

    Emissions of biogenic volatile organic compounds are though to contribute significantly to secondary organic aerosol formation in the tropics, but understanding these transformation processes has proved difficult, due to the complexity of the chemistry involved and very low concentrations. Aerosols from above a Southeast Asian tropical rainforest in Borneo were characterised using liquid chromatography-ion trap mass spectrometry, high-resolution aerosol mass spectrometry and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) techniques. Oxygenated compounds were identified in ambient organic aerosol that could be directly traced back to isoprene, monoterpenes and sesquiterpene emissions, by combining field data on chemical structures with mass spectral data generated from synthetically produced products created in a simulation chamber. Eighteen oxygenated species of biogenic origin were identified in the rainforest aerosol from the precursors isoprene, α-pinene, limonene, α-terpinene and β-caryophyllene. The observations provide the unambiguous field detection of monoterpene and sesquiterpene oxidation products in SOA above a pristine tropical rainforest. The presence of 2-methyl tetrol organosulfates and an associated sulfated dimer provides direct evidence that isoprene in the presence of sulfate aerosol can make a contribution to biogenic organic aerosol above tropical forests. High-resolution mass spectrometry indicates that sulfur can also be incorporated into oxidation products arising from monoterpene precursors in tropical aerosol.

  6. Understanding dust emission in the Bodélé region by extracting locally mobilized dust aerosols from satellite Aerosol Optical Depth data using principal component analysis

    NASA Astrophysics Data System (ADS)

    Parajuli, Sagar Prasad; Yang, Zong-Liang

    2017-02-01

    Despite the increasing availability of satellite and ground-based Aerosol Optical Depth (AOD) data, their application in dust modeling is limited because these data do not differentiate locally mobilized dust from remotely advected dust and other aerosols. In this work, we extract the locally mobilized Dust Optical Depth (DOD) in the Bodélé region from historical AOD data through a principal component analysis of wind speed and AOD time series (2003-2012). Principal component analysis effectively identifies the correlated signature between wind speed and AOD making it possible to separate the dust component from AOD data. Using the reconstructed DOD, we then study the effect of key environmental variables, namely wind speed, soil moisture, soil temperature, vegetation, and boundary layer height on dust emission. Results show that all of these environmental variables are significantly correlated with the reconstructed DOD indicating their association with the dust emission process. The extraction technique described in this study can be extended to regional and global scales to identify the dust sources which are not adequately represented in regional and global dust models.

  7. Role of Climate Change in Predictions of Future Tropospheric Ozone and Aerosols

    NASA Astrophysics Data System (ADS)

    Liao, H.; Chen, W.; Seinfeld, J.

    2006-12-01

    A unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies general circulation model II is applied to simulate equilibrium climate change driven by changes in greenhouse gases (GHGs) and/or aerosols over 2000-2100 to examine the effects of climate change on global distributions of tropospheric ozone and sulfate, nitrate, ammonium, black carbon, primary organic carbon, secondary organic carbon, sea salt, and mineral dust aerosols. We consider only direct radiative effect of aerosols on future climate in this study. Since aerosol levels will both affect and be affected by future climate, we identify the role of aerosol-driven climate in predicting future air pollutants by performing a number of sensitivity studies. The year 2100 GHG concentrations as well as the anthropogenic emissions of ozone precursors and aerosols/aerosol precursors are based on the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (SRES) A2. Although greenhouse gases are the most important drivers of global climate change, aerosols are very influential on regional climate through absorption and scattering of solar radiation. As aerosol concentrations increase over 2000-2100, aerosol-induced cooling at the surface, increase in atmospheric stability, and reduction in precipitation are predicted to increase surface-layer concentrations of pollutants over populated areas; Aerosol-induced climate change is therefore predicted to have a positive feedback to tropospheric aerosol concentrations. We also compare the effect of GHG-driven climate on atmospheric composition with that of aerosol-driven climate. Results suggest that it is important to account for climate responses to aerosol forcing in predicting future ozone and aerosols.

  8. Application of mobile aerosol and trace gas measurements for the investigation of megacity air pollution emissions: the Paris metropolitan area

    NASA Astrophysics Data System (ADS)

    von der Weiden-Reinmüller, S.-L.; Drewnick, F.; Crippa, M.; Prévôt, A. S. H.; Meleux, F.; Baltensperger, U.; Beekmann, M.; Borrmann, S.

    2013-08-01

    For the investigation of megacity emission development and impact outside the source region mobile aerosol and trace gas measurements were carried out in the Paris metropolitan area between 1 July and 31 July 2009 (summer conditions) and 15 January and 15 February 2010 (winter conditions) in the framework of the European Union FP7 MEGAPOLI project. Two mobile laboratories, MoLa and MOSQUITA, were deployed, and here an overview of these measurements and an investigation of the applicability of such measurements for the analysis of megacity emissions are presented. Both laboratories measured physical and chemical properties of fine and ultrafine aerosol particles as well as gas phase constituents of relevance for urban pollution scenarios. The applied measurement strategies include cross section measurements for the investigation of plume structure and quasi-Lagrangian measurements radially away from the city center to study plume aging processes. Results of intercomparison measurements between the two mobile laboratories represent the adopted data quality assurance procedures. Most of the compared measurement devices show sufficient agreement for combined data analysis. For the removal of data contaminated by local pollution emissions a video tape analysis method was applied. Analysis tools like positive matrix factorization and peak integration by key analysis applied to high-resolution time-of-flight aerosol mass spectrometer data are used for in-depth data analysis of the organic particulate matter. Several examples, including a combination of MoLa and MOSQUITA measurements on a cross section through the Paris emission plume are provided to demonstrate how such mobile measurements can be used to investigate the emissions of a megacity. A critical discussion of advantages and limitations of mobile measurements for the investigation of megacity emissions completes this work.

  9. Application of mobile aerosol and trace gas measurements for the investigation of megacity air pollution emissions: the Paris metropolitan area

    NASA Astrophysics Data System (ADS)

    von der Weiden-Reinmüller, S.-L.; Drewnick, F.; Crippa, M.; Prévôt, A. S. H.; Meleux, F.; Baltensperger, U.; Beekmann, M.; Borrmann, S.

    2014-01-01

    For the investigation of megacity emission development and the impact outside the source region, mobile aerosol and trace gas measurements were carried out in the Paris metropolitan area between 1 July and 31 July 2009 (summer conditions) and 15 January and 15 February 2010 (winter conditions) in the framework of the European Union FP7 MEGAPOLI project. Two mobile laboratories, MoLa and MOSQUITA, were deployed, and here an overview of these measurements and an investigation of the applicability of such measurements for the analysis of megacity emissions are presented. Both laboratories measured physical and chemical properties of fine and ultrafine aerosol particles as well as gas phase constituents of relevance for urban pollution scenarios. The applied measurement strategies include cross-section measurements for the investigation of plume structure and quasi-Lagrangian measurements axially along the flow of the city's pollution plume to study plume aging processes. Results of intercomparison measurements between the two mobile laboratories represent the adopted data quality assurance procedures. Most of the compared measurement devices show sufficient agreement for combined data analysis. For the removal of data contaminated by local pollution emissions a video tape analysis method was applied. Analysis tools like positive matrix factorization and peak integration by key analysis applied to high-resolution time-of-flight aerosol mass spectrometer data are used for in-depth data analysis of the organic particulate matter. Several examples, including a combination of MoLa and MOSQUITA measurements on a cross section through the Paris emission plume, are provided to demonstrate how such mobile measurements can be used to investigate the emissions of a megacity. A critical discussion of advantages and limitations of mobile measurements for the investigation of megacity emissions completes this work.

  10. Temporal variability of primary and secondary aerosols over northern India: Impact of biomass burning emissions

    NASA Astrophysics Data System (ADS)

    Rastogi, N.; Singh, A.; Sarin, M. M.; Singh, D.

    2016-01-01

    The ambient particulate matter injected from biomass burning emissions (BBEs) over northern India has been a subject of major debate in the context of regional air quality and atmospheric chemistry of several organic and inorganic constituents. This necessitates an observational approach over a large spatial and temporal scale. We present an extensive data set on PM2.5 samples (n = 147) collected for one full year from a sampling site (Patiala: 30.2°N, 76.3°E) in the source region of BBEs in northern India. During the sampling period from October 2011 to September 2012, PM2.5 mass concentration varied from ˜20 to 400 μg m-3. Among the major constituents, contribution of total carbonaceous aerosols (OC + EC) ranged from 8 to 60%. The average OC/EC and K+/EC ratio, varying from 3.2 to 12 and 0.26 to 0.80, respectively, emphasizes the dominance of BBEs over the annual seasonal cycle. The average secondary organic matter (SOM) accounts for ˜10-40% of PM2.5 mass in different seasons; whereas contribution of secondary inorganics was maximum (˜40%) during the winter. The pronounced temporal variability in SOM suggests its contribution from varying sources, their emission strength and process of secondary organic formation. Diurnal differences in the chemical constituents are attributable to regional meteorological factors and boundary layer dynamics. The emerging data set from this study is important to understand feedback mechanism from anthropogenic activities to the regional climate change scenario.

  11. Emission sources and atmospheric processing of carbonaceous aerosols in India and China: Insights from dual carbon isotope techniques

    NASA Astrophysics Data System (ADS)

    Andersson, A.; Kirillova, E. N.; Bosch, C.; Suresh, T.; Lee, M.; Du, K.; Sheesley, R. J.; Budhavant, K.; Gustafsson, O. M.

    2013-12-01

    The large emissions of carbonaceous aerosols, e.g., black carbon (BC), in India and China have detrimental effects on both human health and the regional climate. However, mitigation efforts as well as accurate modeling of these effects are currently hampered by large uncertainties regarding the contributions from different emission sources, including both primary and secondary processes. Here, we present dual carbon isotope constraints on emissions sources and atmospheric processing from multiple sites capturing the outflow from India and China. Radiocarbon (14C) studies of elemental carbon (EC) - a tracer for BC - show larger relative fossil contributions than expected from bottom-up emission inventories, for both India (49+-5) and China (80 +-6%). Similarly to EC, radiocarbon constraints of water soluble organic carbon (WSOC) shows substantially larger relative fossil contributions in Chinese outflow (30-50%) as compared with India, but also compared to Europe and USA (10-20%). In contrast to the radiocarbon data, stable carbon (d13C) analysis of WSOC shows substantial variability for different sites capturing the Indian outflow. Strong enrichment of heavy isotopes in WSOC is coupled to expected transport time from sources, indicating the influence of photochemical aging during transport. Such trends in the d13C signature are not observed for the EC fraction. Taken together this work show that carbon isotope techniques provide firm constraints on emission sources of different fractions of carbonaceous aerosols, and may also offer insights into atmospheric processing of these constituents during air mass transport.

  12. Origin of surface and columnar Indian Ocean Experiment (INDOEX) aerosols using source- and region-tagged emissions transport in a general circulation model - article no. D24211

    SciTech Connect

    Verma, S.; Venkataraman, C.; Boucher, O.

    2008-12-15

    We study the relative influence of aerosols emitted from different sectors and geographical regions on aerosol loading in south Asia. Sectors contributing aerosol emissions include biofuel and fossil fuel combustion, open biomass burning, and natural sources. Geographical regions include India, southeast Asia, east Asia, Africa-west Asia, and the rest of the world. Simulations of the Indian Ocean Experiment (INDOEX), from January to March 1999, are made in the general circulation model of Laboratoire de Meteorologie Dynamique (LMD-ZT GCM) with emissions tagged by sector and geographical region. Anthropogenic emissions dominate (54-88%) the predicted aerosol optical depth (AOD) over all the receptor regions. Among the anthropogenic sectors, fossil fuel combustion has the largest overall influence on aerosol loading, primarily sulfate, with emissions from India (50-80%) and rest of the world significantly influencing surface concentrations and AOD. Biofuel combustion has a significant influence on both the surface and columnar black carbon (BC) in particular over the Indian subcontinent and Bay of Bengal with emissions largely from the Indian region (60-80%). Open biomass burning emissions influence organic matter (OM) significantly, and arise largely from Africa-west Asia. The emissions from Africa-west Asia affect the carbonaceous aerosols AOD in all receptor regions, with their largest influence (AOD-BC: 60%; and AOD-OM: 70%) over the Arabian Sea. Among Indian regions, the Indo-Gangetic Plain is the largest contributor to anthropogenic surface mass concentrations and AOD over the Bay of Bengal and India. Dust aerosols are contributed mainly through the long-range transport from Africa-west Asia over the receptor regions. Overall, the model estimates significant intercontinental incursion of aerosol, for example, BC, OM, and dust from Africa-west Asia and sulfate from distant regions (rest of the world) into the INDOEX domain.

  13. Aerosol particle and trace gas emissions from earthworks, road construction, and asphalt paving in Germany: Emission factors and influence on local air quality

    NASA Astrophysics Data System (ADS)

    Faber, Peter; Drewnick, Frank; Borrmann, Stephan

    2015-12-01

    Aerosol emissions from construction sites have a strong impact on local air quality. The chemical and physical characteristics of particles and trace gases emitted by earthworks (excavation and loading of soil as well as traffic on unpaved roads) and road works (asphalt sawing, smashing, soil compacting, asphalt paving) have therefore been addressed in this study by using a mobile set-up of numerous modern online aerosol and trace gas instruments including a high-resolution aerosol mass spectrometer. Fuel-based emission factors for several variables have been determined, showing that earthwork activities and compacting by use of a plate compactor revealed the highest median emission factors for PM10 (up to 54 g l-1). Construction activities were assigned to contribute about 17% (36 000 t a-1) to total PM10 emissions and 3% (13 500 t a-1) to total traffic-related NOx emissions in Germany. In particular, calculated PM10 emissions by earthworks are about 15 800 t a-1 corresponding to 44% of total PM10 emissions by construction activities in Germany. Mechanical processes such as asphalt sawing (PM1/PM10 = 18 ± 31%), soil compacting by a plate compactor (PM1/PM10 = 5 ± 6%) and earthworks (PM1/PM10 = 2 ± 5%) emit predominantly coarse mineral dust particles. Contrary to that, particle emissions by thermal construction processes (asphalt paving: PM1/PM10 = 62 ± 14%) and by the internal combustion engines of heavy machinery (e.g. road roller PM1/PM10 = 94 ± 9%) are mostly in the submicron range. These particles were mainly composed of organics containing non-polar saturated and unsaturated hydrocarbons (e.g. asphalting: O:C < 0.01, H:C = 2.01). Besides construction activities, mineral dust is also emitted over cleared land by wind-driven resuspension depending on wind speed. PM10 emissions by construction activities often result in local concentrations > 100 μg m-3 and can easily breach the European limit level of PM10. This study also shows that particulate mineral

  14. Historical emissions of black and organic carbon aerosol from energy-related combustion, 1850-2000 - article no. GB2018

    SciTech Connect

    Bond, T.C.; Bhardwaj, E.; Dong, R.; Jogani, R.; Jung, S.K.; Roden, C.; Streets, D.G.; Trautmann, N.M.

    2007-05-15

    We present an emission inventory of primary black carbon (BC) and primary organic carbon (OC) aerosols from fossil fuel and biofuel combustion between 1850 and 2000. We reconstruct fossil fuel consumption and represent changes in technology on a national and sectoral basis. Our estimates rely on new estimates of biofuel consumption, and updated emission factors for old technologies. Emissions of black carbon increase almost linearly, totaling about 1000 Gg in 1850, 2200 Gg in 1900, 3000 Gg in 1950, and 4400 Gg in 2000. Primary organic carbon shows a similar pattern, with emissions of 4100 Gg, 5800 Gg, 6700 Gg, and 8700 Gg in 1850, 1900, 1950, and 2000, respectively. Biofuel is responsible for over half of BC emission until about 1890, and dominates energy-related primary OC emission throughout the entire period. Coal contributes the greatest fraction of BC emission between 1880 and 1975, and is overtaken by emissions from biofuel around 1975, and by diesel engines around 1990. Previous work suggests a rapid rise in BC emissions between 1950 and 2000. This work supports a more gradual increase between 1950 and 2000, similar to the increase between 1850 and 1925; implementation of clean technology is a primary reason.

  15. Intermediate Volatility Organic Compound Emissions from On-Road Diesel Vehicles: Chemical Composition, Emission Factors, and Estimated Secondary Organic Aerosol Production.

    PubMed

    Zhao, Yunliang; Nguyen, Ngoc T; Presto, Albert A; Hennigan, Christopher J; May, Andrew A; Robinson, Allen L

    2015-10-06

    Emissions of intermediate-volatility organic compounds (IVOCs) from five on-road diesel vehicles and one off-road diesel engine were characterized during dynamometer testing. The testing evaluated the effects of driving cycles, fuel composition and exhaust aftertreatment devices. On average, more than 90% of the IVOC emissions were not identified on a molecular basis, instead appearing as an unresolved complex mixture (UCM) during gas-chromatography mass-spectrometry analysis. Fuel-based emissions factors (EFs) of total IVOCs (speciated + unspeciated) depend strongly on aftertreatment technology and driving cycle. Total-IVOC emissions from vehicles equipped with catalyzed diesel particulate filters (DPF) are substantially lower (factor of 7 to 28, depending on driving cycle) than from vehicles without any exhaust aftertreatment. Total-IVOC emissions from creep and idle operations are substantially higher than emissions from high-speed operations. Although the magnitude of the total-IVOC emissions can vary widely, there is little variation in the IVOC composition across the set of tests. The new emissions data are combined with published yield data to investigate secondary organic aerosol (SOA) formation. SOA production from unspeciated IVOCs is estimated using surrogate compounds, which are assigned based on gas-chromatograph retention time and mass spectral signature of the IVOC UCM. IVOCs contribute the vast majority of the SOA formed from exhaust from on-road diesel vehicles. The estimated SOA production is greater than predictions by previous studies and substantially higher than primary organic aerosol. Catalyzed DPFs substantially reduce SOA formation potential of diesel exhaust, except at low speed operations.

  16. How Important Is Organic Aerosol Hygroscopicity to Aerosol Indirect Forcing?

    SciTech Connect

    Liu, Xiaohong; Wang, Jian

    2010-12-07

    Organics are among the most abundant aerosol components in the atmosphere. However, there are still large uncertainties with emissions of primary organic aerosol (POA) and volatile organic compounds (VOCs) (precursor gases of secondary organic aerosol, SOA), formation and yield of SOA, and chemical and physical properties (e.g., hygroscopicity) of POA and SOA. All these may have significant impacts on aerosol direct and indirect forcing estimated from global models. In this study a modal aerosol module (MAM) in the NCAR Community Atmospheric Model (CAM) is used to examine sensitivities of aerosol indirect forcing to hygroscopicity (“κ” value) of POA and SOA. Our model simulation indicates that in the present-day condition changing “κ” value of POA from 0 to 0.1 increases the number concentration of cloud condensational nuclei (CCN) at supersaturation S=0.1% by 40-60% over the POA source regions, while changing “κ” value of SOA by ±50% (from 0.14 to 0.07 and 0.21) changes the CCN within 30%. Changes in the in-cloud droplet number concentrations (CDNC) are within 20% in most locations on the globe with the above changes in “κ” value of POA and SOA. Global annual mean anthropogenic aerosol indirect forcing (AIF) between present-day (PD) and pre-industrial (PI) conditions change by 0.4 W m-2 with the control run of -1.3 W m-2. AIF reduces with the increase hygroscopicity of organic aerosol, indicating the important role of natural organic aerosol in buffering the relative change of CDNC from PI to PD.

  17. Change in global aerosol composition since preindustrial times

    NASA Astrophysics Data System (ADS)

    Tsigaridis, K.; Krol, M.; Dentener, F. J.; Balkanski, Y.; Lathière, J.; Metzger, S.; Hauglustaine, D. A.; Kanakidou, M.

    2006-06-01

    increased by 11%. The increase in oxidant levels and preexisting aerosol mass since preindustrial times is the reason of the burden change, since emissions have not changed significantly. The computed aerosol composition changes translate into about 2.5 times more water associated with non sea-salt aerosol. Additionally, aerosols contain 2.7 times more inorganic components nowadays than during the preindustrial times. We find that the increase in emissions of inorganic aerosol precursors is much larger than the corresponding aerosol increase, reflecting a non-linear atmospheric response.

  18. Change in global aerosol composition since preindustrial times

    NASA Astrophysics Data System (ADS)

    Tsigaridis, K.; Krol, M.; Dentener, F. J.; Balkanski, Y.; Lathière, J.; Metzger, S.; Hauglustaine, D. A.; Kanakidou, M.

    2006-11-01

    by 11%. The increase in oxidant levels and preexisting aerosol mass since preindustrial times is the reason of the burden change, since emissions have not changed significantly. The computed aerosol composition changes translate into about 2.5 times more water associated with non sea-salt aerosol. Additionally, aerosols contain 2.7 times more inorganic components nowadays than during the preindustrial times. We find that the increase in emissions of inorganic aerosol precursors is much larger than the corresponding aerosol increase, reflecting a non-linear atmospheric response.

  19. Effects of emission reductions on organic aerosol in the southeastern United States

    NASA Astrophysics Data System (ADS)

    Blanchard, C. L.; Hidy, G. M.; Shaw, S.; Baumann, K.; Edgerton, E. S.

    2016-01-01

    Long-term (1999 to 2013) data from the Southeastern Aerosol Research and Characterization (SEARCH) network are used to show that anthropogenic emission reductions led to important decreases in fine-particle organic aerosol (OA) concentrations in the southeastern US On average, 45 % (range 25 to 63 %) of the 1999 to 2013 mean organic carbon (OC) concentrations are attributed to combustion processes, including fossil fuel use and biomass burning, through associations of measured OC with combustion products such as elemental carbon (EC), carbon monoxide (CO), and nitrogen oxides (NOx). The 2013 mean combustion-derived OC concentrations were 0.5 to 1.4 µg m-3 at the five sites operating in that year. Mean annual combustion-derived OC concentrations declined from 3.8 ± 0.2 µg m-3 (68 % of total OC) to 1.4 ± 0.1 µg m-3 (60 % of total OC) between 1999 and 2013 at the urban Atlanta, Georgia, site (JST) and from 2.9 ± 0.4 µg m-3 (39 % of total OC) to 0.7 ± 0.1 µg m-3 (30 % of total OC) between 2001 and 2013 at the urban Birmingham, Alabama (BHM), site. The urban OC declines coincide with reductions of motor vehicle emissions between 2006 and 2010, which may have decreased mean OC concentrations at the urban SEARCH sites by > 2 µg m-3. BHM additionally exhibits a decline in OC associated with SO2 from 0.4 ± 0.04 µg m-3 in 2001 to 0.2 ± 0.03 µg m-3 in 2013, interpreted as the result of reduced emissions from industrial sources within the city. Analyses using non-soil potassium as a biomass burning tracer indicate that biomass burning OC occurs throughout the year at all sites. All eight SEARCH sites show an association of OC with sulfate (SO4) ranging from 0.3 to 1.0 µg m-3 on average, representing ˜ 25 % of the 1999 to 2013 mean OC concentrations. Because the mass of OC identified with SO4 averages 20 to 30 % of the SO4 concentrations, the mean SO4-associated OC declined by ˜ 0.5 to 1 µg m-3 as SO4 concentrations decreased throughout the SEARCH region. The

  20. Effects of emission reductions on organic aerosol in the southeastern United States

    NASA Astrophysics Data System (ADS)

    Blanchard, C. L.; Hidy, G. M.; Shaw, S.; Baumann, K.; Edgerton, E. S.

    2015-06-01

    Long-term (1999 to 2013) data from the Southeastern Aerosol Research and Characterization (SEARCH) network are used to characterize the effects of anthropogenic emission reductions on fine particle organic aerosol (OA) concentrations in the southeastern US. On average, 45 % (range 25 to 63 %) of the 1999 to 2013 mean organic carbon (OC) concentrations are attributed to combustion processes, including fossil-fuel use and biomass burning, through associations of measured OC with combustion products such as elemental carbon (EC), carbon monoxide (CO), and nitrogen oxides (NOx). The 2013 mean combustion-derived OC concentrations were 0.5 to 1.4 μg m-3 at the five sites operating in that year. Mean annual combustion-derived OC concentrations declined from 3.8 ± 0.2 μg m-3 (68 % of total OC) to 1.4 ± 0.1 μg m-3 (60 % of total OC) between 1999 and 2013 at the urban Atlanta, Georgia, site (JST) and from 2.9 ± 0.4 μg m-3 (39 % of total OC) to 0.7 ± 0.1 μg m-3 (30 % of total OC) between 2001 and 2013 at the urban Birmingham, Alabama, site (BHM). The urban OC declines coincide with reductions of motor-vehicle emissions between 2006 and 2010, which may have decreased mean OC concentrations at the urban SEARCH sites by > 2 μg m-3. BHM additionally exhibits a decline in OC associated with SO2 from 0.4 ± 0.04 μg m-3 in 2001 to 0.2 ± 0.03 μg m-3 in 2013, interpreted as the result of reduced emissions from industrial sources within the city. Analyses using non-soil potassium as a biomass-burning tracer indicate that biomass-burning OC occurs throughout the year at all sites. All eight SEARCH sites show an association of OC with sulfate (SO4) ranging from 0.3 to 1.0 μg m-3 on average, representing ~ 25 % of the 1999 to 2013 mean OC concentrations. Because the mass of OC associated with SO4 averages 20 to 30 % of the SO4 concentrations, the mean SO4-associated OC declined by ~ 0.5 to 1 μg m-3 as SO4 decreased throughout the SEARCH region. The 2013 mean SO4

  1. The impact of biogenic carbon emissions on aerosol absorption inMexico City

    SciTech Connect

    Marley, N; Gaffney, J; Tackett, M J; Sturchio, N; Hearty, L; Martinez, N; Hardy, K D; Machany-Rivera, A; Guilderson, T P; MacMillan, A; Steelman, K

    2009-02-24

    In order to determine the wavelength dependence of atmospheric aerosol absorption in the Mexico City area, the absorption angstrom exponents (AAEs) were calculated from aerosol absorption measurements at seven wavelengths obtained with a seven-channel aethalometer during two field campaigns, the Mexico City Metropolitan Area study in April 2003 (MCMA 2003) and the Megacity Initiative: Local and Global Research Observations in March 2006 (MILAGRO). The AAEs varied from 0.76 to 1.56 in 2003 and from 0.54 to 1.52 in 2006. The AAE values determined in the afternoon were consistently higher than the corresponding morning values, suggesting the photochemical formation of absorbing secondary organic aerosols (SOA) in the afternoon. The AAE values were compared to stable and radiocarbon isotopic measurements of aerosol samples collected at the same time to determine the sources of the aerosol carbon. The fraction of modern carbon (fM) in the aerosol samples, as determined from {sup 14}C analysis, showed that 70% of the carbonaceous aerosols in Mexico City were from modern sources, indicating a significant impact from biomass burning during both field campaigns. The {sup 13}C/{sup 12}C ratios of the aerosol samples illustrate the significant impact of Yucatan forest fires (C-3 plants) in 2003 and local grass fires (C-4 plants) at site T1 in 2006. A direct comparison of the fM values, stable carbon isotope ratios, and calculated aerosol AAEs suggested that the wavelength dependence of the aerosol absorption was controlled by the biogenically derived aerosol components.

  2. Spatial variations in immediate greenhouse gases and aerosol emissions and resulting radiative forcing from wildfires in interior Alaska

    NASA Astrophysics Data System (ADS)

    Huang, Shengli; Liu, Heping; Dahal, Devendra; Jin, Suming; Li, Shuang; Liu, Shuguang

    2016-02-01

    Boreal fires can cool the climate; however, this conclusion came from individual fires and may not represent the whole story. We hypothesize that the climatic impact of boreal fires depends on local landscape heterogeneity such as burn severity, prefire vegetation type, and soil properties. To test this hypothesis, spatially explicit emission of greenhouse gases (GHGs) and aerosols and their resulting radiative forcing are required as an important and necessary component towards a full assessment. In this study, we integrated remote sensing (Landsat and MODIS) and models (carbon consumption model, emission factors model, and radiative forcing model) to calculate the carbon consumption, GHGs and aerosol emissions, and their radiative forcing of 2001-2010 fires at 30 m resolution in the Yukon River Basin of Alaska. Total carbon consumption showed significant spatial variation, with a mean of 2,615 g C m-2 and a standard deviation of 2,589 g C m-2. The carbon consumption led to different amounts of GHGs and aerosol emissions, ranging from 593.26 Tg (CO2) to 0.16 Tg (N2O). When converted to equivalent CO2 based on global warming potential metric, the maximum 20 years equivalent CO2 was black carbon (713.77 Tg), and the lowest 20 years equivalent CO2 was organic carbon (-583.13 Tg). The resulting radiative forcing also showed significant spatial variation: CO2, CH4, and N2O can cause a 20-year mean radiative forcing of 7.41 W m-2 with a standard deviation of 2.87 W m-2. This emission forcing heterogeneity indicates that different boreal fires have different climatic impacts. When considering the spatial variation of other forcings, such as surface shortwave forcing, we may conclude that some boreal fires, especially boreal deciduous fires, can warm the climate.

  3. Characterization of particulate matter emissions from on-road gasoline and diesel vehicles using a soot particle aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Dallmann, T. R.; Onasch, T. B.; Kirchstetter, T. W.; Worton, D. R.; Fortner, E. C.; Herndon, S. C.; Wood, E. C.; Franklin, J. P.; Worsnop, D. R.; Goldstein, A. H.; Harley, R. A.

    2014-02-01

    Particulate matter (PM) emissions were measured in July 2010 from on-road motor vehicles driving through a highway tunnel in the San Francisco Bay area. A soot particle aerosol mass spectrometer (SP-AMS) was used to measure the chemical composition of PM emitted by gasoline and diesel vehicles at high time resolution. Organic aerosol (OA) and black carbon (BC) concentrations were measured during various time periods that had different levels of diesel influence, as well as directly in the exhaust plumes of individual heavy-duty (HD) diesel trucks. BC emission factor distributions for HD trucks were more skewed than OA distributions, with the highest 10% of trucks accounting for 56 and 42% of total measured BC and OA emissions, respectively. A comparison of measured OA and BC mass spectra across various sampling periods revealed a high degree of similarity in BC and OA emitted by gasoline and diesel engines. Cycloalkanes predominate in exhaust OA emissions relative to saturated alkanes (i.e., normal and iso-paraffins), suggesting that lubricating oil rather than fuel is the dominant source of primary organic aerosol (POA) emissions in diesel vehicle exhaust. This finding is supported by the detection of trace elements such as zinc and phosphorus in the exhaust plumes of individual trucks. Trace elements were emitted relative to total OA at levels that are consistent with typical weight fractions of commonly used additives present in lubricating oil. The presence of trace elements in vehicle exhaust raises the concern that ash deposits may accumulate over time in diesel particle filter systems, and may eventually lead to performance problems that require servicing.

  4. Characterization of particulate matter emissions from on-road gasoline and diesel vehicles using a soot particle aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Dallmann, T. R.; Onasch, T. B.; Kirchstetter, T. W.; Worton, D. R.; Fortner, E. C.; Herndon, S. C.; Wood, E. C.; Franklin, J. P.; Worsnop, D. R.; Goldstein, A. H.; Harley, R. A.

    2014-07-01

    Particulate matter (PM) emissions were measured in July 2010 from on-road motor vehicles driving through a highway tunnel in the San Francisco Bay area. A soot particle aerosol mass spectrometer (SP-AMS) was used to measure the chemical composition of PM emitted by gasoline and diesel vehicles at high time resolution. Organic aerosol (OA) and black carbon (BC) concentrations were measured during various time periods that had different levels of diesel influence, as well as directly in the exhaust plumes of individual heavy-duty (HD) diesel trucks. BC emission factor distributions for HD trucks were more skewed than OA distributions (N = 293), with the highest 10% of trucks accounting for 56 and 42% of total measured BC and OA emissions, respectively. OA mass spectra measured for HD truck exhaust plumes show cycloalkanes are predominate in exhaust OA emissions relative to saturated alkanes (i.e., normal and iso-paraffins), suggesting that lubricating oil rather than fuel is the dominant source of primary organic aerosol (POA) emissions in diesel vehicle exhaust. This finding is supported by the detection of trace elements such as zinc and phosphorus in the exhaust plumes of individual trucks. Trace elements were emitted relative to total OA at levels that are consistent with typical weight fractions of commonly used additives present in lubricating oil. A comparison of measured OA and BC mass spectra across various sampling periods revealed a high degree of similarity in OA and BC emitted by gasoline and diesel engines. This finding indicates a large fraction of OA in gasoline exhaust is lubricant-derived as well. The similarity in OA and BC mass spectra for gasoline and diesel engine exhaust is likely to confound ambient source apportionment efforts to determine contributions to air pollution from these two important sources.

  5. Micro-Raman Spectroscopy to Complement Proton-Induced X-Ray Emission in the Analysis of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Safiq, Alexandrea; Ali, Salina; Nadarski, Benjamin; Smith, Jeremy; Yoskowitz, Josh; Labrake, Scott; Vineyard, Michael; Union College Team

    2013-10-01

    There is an active research program in the Union College Ion-Beam Analysis Laboratory on proton-induced X-ray emission (PIXE) analysis of atmospheric aerosols. PIXE is a powerful tool for the study of airborne pollution because it provides information on a broad range of elements simultaneously, has low detection limits, is nondestructive, does not require large samples, and the analysis can be performed in a short amount of time. However, PIXE provides only elemental information. We are investigating the use of Micro-Raman spectroscopy (MRS) to complement PIXE analysis of aerosol samples by providing chemical information. In MRS, laser light is inelastically scattered from a sample and the vibrational spectrum of the scattered light is used to identify molecules and their functional groups. We are focusing on aerosol samples collected in the Adirondack Mountains that have considerable concentrations of sulfur that may contribute to acid rain. The MRS spectra collected on aerosol samples are being compared with a library of standards to try to determine the molecular structures in which the sulfur is bound. We will describe the analysis and present preliminary results. Union College Undergraduate Research Program.

  6. 77 FR 14279 - National Volatile Organic Compound Emission Standards for Aerosol Coatings-Addition of Dimethyl...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... aerosol coatings category (aerosol spray paints) under the Clean Air Act, published elsewhere in the... Primers, Surfacers or Undercoaters........ PCS 1.05 Pleasure Craft Topcoats PCT 0.60 Polyolefin Adhesion....35 Benzene 71-43-2 0.81 1,1,1-Trichloroethane 71-55-6 0.00 Propane 74-98-6 0.56 Vinyl Chloride...

  7. A new description of Titan's aerosol optical properties from the analysis of VIMS Emission Phase Function observations

    NASA Astrophysics Data System (ADS)

    Rodriguez, Sebastien; Maltagliati, Luca; Sotin, Christophe; Rannou, Pascal; Bézard, Bruno; Cornet, Thomas

    2016-10-01

    The Huygens probe gave unprecedented information on the properties of Titan's aerosols (vertical distribution, opacity as a function of wavelength, phase function, single scattering albedo) by in-situ measurements (Tomasko et al. 2008). Being the only existing in-situ atmospheric probing for Titan, this aerosol model currently is the reference for many Titan studies (e.g. by being applied as physical input in radiative transfer models of the atmosphere). Recently a reanalysis of the DISR dataset, corroborated by data from the Downward-Looking Visible Spectrometer (DLVS), was carried out by the same group (Doose et al. 2016), leading to significant changes to the indications given by Tomasko et al. (2008).Here we present the analysis of the Emission Phase Function observation (EPF) performed by VIMS during the Cassini flyby T88 (November 2012). An EPF observes the same spot on the surface (and thus the same atmosphere) with the same emergence angle but with different incidence angles. In this way, our EPF allows, for the first time, to have direct information on the phase function of Titan's aerosols, as well as on other important physical parameters of the aerosols as the behavior of their extinction as a function of wavelength and the single scattering albedo (also as a function of wavelength) for the whole VIMS range (0.8-5.2 μm). The T88 EPF is composed of 25 VIMS datacubes spanning a scattering angle range approximately from 0°to 70°.We used the radiative transfer model described in Hirtzig et al. (2013) as baseline, updated with improved methane (+ related isotopes) spectroscopy. By changing the aerosol description in the model, we found the combination of aerosol optical parameters that fits best a constant aerosol column density over the whole set of the VIMS datacubes. We confirmed that the new results from Doose et al. (2016) do improve the fit for what concerns the vertical profile and the extinction as a function of wavelength. However, a different

  8. A new description of Titan's aerosol optical properties from the analysis of VIMS Emission Phase Function observations

    NASA Astrophysics Data System (ADS)

    Maltagliati, Luca; Rodriguez, Sebastien; Sotin, Christophe; Rannou, Pascal; Bezard, Bruno; Cornet, Thomas

    2016-06-01

    The Huygens probe gave unprecedented information on the properties of Titan's aerosols (vertical distribution, opacity as a function of wavelength, phase function, single scattering albedo) by in-situ measurements (Tomasko et al. 2008). Being the only existing in-situ atmospheric probing for Titan, this aerosol model currently is the reference for many Titan studies (e.g. by being applied as physical input in radiative transfer models of the atmosphere). Recently a reanalysis of the DISR dataset, corroborated by data from the Downward-Looking Visible Spectrometer (DLVS), was carried out by the same group (Doose et al. 2016), leading to significant changes to the indications given by Tomasko et al. (2008). Here we present the analysis of the Emission Phase Function observation (EPF) performed by VIMS during the Cassini flyby T88 (November 2012). An EPF observes the same spot on the surface (and thus the same atmosphere) with the same emergence angle but with different incidence angles. In this way, our EPF allows, for the first time, to have direct information on the phase function of Titan's aerosols, as well as on other important physical parameters of the aerosols as the behavior of their extinction as a function of wavelength and the single scattering albedo (also as a function of wavelength) for the whole VIMS range (0.8-5.2 µm). The T88 EPF is composed of 25 VIMS datacubes spanning a scattering angle range approximately from 0°to 70°. We used the radiative transfer model described in Hirtzig et al. (2013) as baseline, updated with improved methane (+ related isotopes) spectroscopy. By changing the aerosol description in the model, we found the combination of aerosol optical parameters that fits best a constant aerosol column density over the whole set of the VIMS datacubes. We confirmed that the new results from Doose et al. (2016) do improve the fit for what concerns the vertical profile and the extinction as a function of wavelength. However, a different

  9. Influences of upwind emission sources and atmospheric processing on aerosol chemistry and properties at a rural location in the Northeastern U.S.

    SciTech Connect

    Zhou, Shan; Collier, Sonya; Xu, Jianzhong; Mei, Fan; Wang, Jian; Lee, Yin -Nan; Sedlacek, III, Arthur J.; Springston, Stephen R.; Sun, Yele; Zhang, Qi

    2016-05-19

    Continuous real-time measurements of atmospheric aerosol with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer coupled with a fast temperature-stepping thermodenuder were carried out in summer 2011 at Brookhaven National Laboratory (BNL, 40.871°N, 72.89°W) during the Department of Energy Aerosol Life Cycle Intensive Operational Period campaign. BNL was frequently downwind of emissions from the New York metropolitan area and was exposed to various combinations of anthropogenic, biogenic, and marine emissions based on air mass history. The average concentration of submicrometer aerosol (PM1) during this study was 12.6 µg m–3 with 64% of the mass being organic. Organic aerosol (OA) at BNL was found to be overwhelmingly secondary, consisting of (1) a fresher, semivolatile oxygenated organic aerosol (SV-OOA; oxygen-to-carbon ratio (O/C) = 0.54; 63% of OA mass) that was strongly influenced by transported urban plumes; (2) a regional, more aged, low-volatility OOA (LV-OOA; O/C = 0.97; 29% of OA mass) influenced by aqueous-phase processing; and (3) a nitrogen-enriched OA (NOA; nitrogen-to-carbon ratio (N/C) = 0.185; 8% of OA mass) likely composed of amine salts formed from acid-base reactions in industrial emissions. Urban emissions from the New York metropolitan areas to the W and SW in particular led to elevated PM1 mass concentration and altered aerosol composition at BNL. Transported urban plumes and local biogenic emissions likely interacted to enhance secondary organic aerosol production, primarily represented by SV-OOA. Lastly, these results suggest an important role that urban anthropogenic emissions play in affecting ambient PM concentration, composition, and physical-chemical properties at rural areas in the Northeast U.S.

  10. Influences of upwind emission sources and atmospheric processing on aerosol chemistry and properties at a rural location in the Northeastern U.S.

    DOE PAGES

    Zhou, Shan; Collier, Sonya; Xu, Jianzhong; ...

    2016-05-19

    Continuous real-time measurements of atmospheric aerosol with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer coupled with a fast temperature-stepping thermodenuder were carried out in summer 2011 at Brookhaven National Laboratory (BNL, 40.871°N, 72.89°W) during the Department of Energy Aerosol Life Cycle Intensive Operational Period campaign. BNL was frequently downwind of emissions from the New York metropolitan area and was exposed to various combinations of anthropogenic, biogenic, and marine emissions based on air mass history. The average concentration of submicrometer aerosol (PM1) during this study was 12.6 µg m–3 with 64% of the mass being organic. Organic aerosol (OA) at BNLmore » was found to be overwhelmingly secondary, consisting of (1) a fresher, semivolatile oxygenated organic aerosol (SV-OOA; oxygen-to-carbon ratio (O/C) = 0.54; 63% of OA mass) that was strongly influenced by transported urban plumes; (2) a regional, more aged, low-volatility OOA (LV-OOA; O/C = 0.97; 29% of OA mass) influenced by aqueous-phase processing; and (3) a nitrogen-enriched OA (NOA; nitrogen-to-carbon ratio (N/C) = 0.185; 8% of OA mass) likely composed of amine salts formed from acid-base reactions in industrial emissions. Urban emissions from the New York metropolitan areas to the W and SW in particular led to elevated PM1 mass concentration and altered aerosol composition at BNL. Transported urban plumes and local biogenic emissions likely interacted to enhance secondary organic aerosol production, primarily represented by SV-OOA. Lastly, these results suggest an important role that urban anthropogenic emissions play in affecting ambient PM concentration, composition, and physical-chemical properties at rural areas in the Northeast U.S.« less

  11. Towards the regulation of aerosol emissions by their potential health impact: Assessing adverse effects of aerosols from wood combustion and ship diesel engine emissions by combining comprehensive data on the chemical composition and their toxicological effects on human lung cells

    NASA Astrophysics Data System (ADS)

    Zimmermann, R.; Streibel, T.; Dittmar, G.; Kanashova, T.; Buters, J.; Öder, S.; Paur, H. R.; Dilger, M.; Weiss, C.; Harndorf, H.; Stengel, B.; Hirvonen, M. R.; Jokiniemi, J.; Hiller, K.; Sapcariu, S.; Sippula, O.; Orasche, J.; Müller, L.; Rheda, A.; Passig, J.; Radischat, C.; Czech, H.; Tiita, P.; Jalava, P.; Kasurinen, S.; Schwemer, T.; Yli-Prilä, P.; Tissari, J.; Lamberg, H.; Schnelle-Kreis, J.

    2014-12-01

    Ship engine emissions are important regarding lung and cardiovascular diseases in coastal regions worldwide. Bio mass burning is made responsible for adverse health effects in many cities and rural regions. The Virtual Helmholtz Institute-HICE (www.hice-vi.eu) addresses chemical & physical properties and health effects of anthropogenic combustion emissions. Typical lung cell responses to combustion aerosols include inflammation and apoptosis, but a molecular link with the specific chemical composition in particular of ship emissions has not been established. Through an air-liquid interface exposure system (ALI), we exposed human lung cells at-site to exhaust fumes from a ship engine running on common heavy fuel oil (HFO) and cleaner-burning diesel fuel (DF) as well as to emissions of wood combustion compliances. A special field deployable ALI-exposition system and a mobile S2-biological laboratory were developed for this study. Human alveolar basal epithelial cells (A549 etc.) are ALI-exposed to fresh, diluted (1:40-1:100) combustion aerosols and subsequently were toxicologically and molecular-biologically characterized. Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling to characterise the cellular responses. The HFO ship emissions contained high concentrations of toxic compounds (transition metals, organic toxicants) and particle masses. The cellular responses included inflammation and oxidative stress. Surprisingly, the DF ship emissions, which predominantly contain rather "pure" carbonaceous soot and much less known toxicants, induced significantly broader biological effects, affecting essential cellular pathways (e.g., mitochondrial function and intracellular transport). Therefore the use of distillate fuels for shipping (this is the current emission reduction strategy of the IMO) appears insufficient for diminishing health effects. The study suggests rather reducing the particle emissions

  12. Aerosol emission monitoring in the production of silicon carbide nanoparticles by induction plasma synthesis

    NASA Astrophysics Data System (ADS)

    Thompson, Drew; Leparoux, Marc; Jaeggi, Christian; Buha, Jelena; Pui, David Y. H.; Wang, Jing

    2013-12-01

    In this study, the synthesis of silicon carbide (SiC) nanoparticles in a prototype inductively coupled thermal plasma reactor and other supporting processes, such as the handling of precursor material, the collection of nanoparticles, and the cleaning of equipment, were monitored for particle emissions and potential worker exposure. The purpose of this study was to evaluate the effectiveness of engineering controls and best practice guidelines developed for the production and handling of nanoparticles, identify processes which result in a nanoparticle release, characterize these releases, and suggest possible administrative or engineering controls which may eliminate or control the exposure source. No particle release was detected during the synthesis and collection of SiC nanoparticles and the cleaning of the reactor. This was attributed to most of these processes occurring in closed systems operated at slight underpressure. Other tasks occurring in more open spaces, such as the disconnection of a filter assembly from the reactor system and the use of compressed air for the cleaning of filters where synthesized SiC nanoparticles were collected, resulted in releases of submicrometer particles with a mode size of 170-180 nm. Observation of filter samples under scanning electron microscope confirmed that the particles were agglomerates of SiC nanoparticles.

  13. Primary emissions and secondary organic aerosol formation from the exhaust of a flex-fuel (ethanol) vehicle

    NASA Astrophysics Data System (ADS)

    Suarez-Bertoa, R.; Zardini, A. A.; Platt, S. M.; Hellebust, S.; Pieber, S. M.; El Haddad, I.; Temime-Roussel, B.; Baltensperger, U.; Marchand, N.; Prévôt, A. S. H.; Astorga, C.

    2015-09-01

    Incentives to use biofuels may result in increasing vehicular emissions of compounds detrimental to air quality. Therefore, regulated and unregulated emissions from a Euro 5a flex-fuel vehicle, tested using E85 and E75 blends (gasoline containing 85% and 75% of ethanol (vol/vol), respectively), were investigated at 22 and -7 °C over the New European Driving Cycle, at the Vehicle Emission Laboratory at the European Commission Joint Research Centre Ispra, Italy. Vehicle exhaust was comprehensively analyzed at the tailpipe and in a dilution tunnel. A fraction of the exhaust was injected into a mobile smog chamber to study the photochemical aging of the mixture. We found that emissions from a flex-fuel vehicle, fueled by E85 and E75, led to secondary organic aerosol (SOA) formation, despite the low aromatic content of these fuel blends. Emissions of regulated and unregulated compounds, as well as emissions of black carbon (BC) and primary organic aerosol (POA) and SOA formation were higher at -7 °C. The flex-fuel unregulated emissions, mainly composed of ethanol and acetaldehyde, resulted in very high ozone formation potential and SOA, especially at low temperature (860 mg O3 km-1 and up to 38 mg C kg-1). After an OH exposure of 10 × 106 cm-3 h, SOA mass was, on average, 3 times larger than total primary particle mass emissions (BC + POA) with a high O:C ratio (up to 0.7 and 0.5 at 22 and -7 °C, respectively) typical of highly oxidized mixtures. Furthermore, high resolution organic mass spectra showed high 44/43 ratios (ratio of the ions m/z 44 and m/z 43) characteristic of low-volatility oxygenated organic aerosol. We also hypothesize that SOA formation from vehicular emissions could be due to oxidation products of ethanol and acetaldehyde, both short-chain oxygenated VOCs, e.g. methylglyoxal and acetic acid, and not only from aromatic compounds.

  14. A global emission inventory of carbonaceous aerosol from historic records of fossil fuel and biofuel consumption for the period 1860-1997

    NASA Astrophysics Data System (ADS)

    Junker, C.; Liousse, C.

    2008-03-01

    Country by country emission inventories for carbonaceous aerosol for the period 1860 to 1997 have been constructed on the basis of historic fuel production, use and trade data sets published by the United Nation's Statistical Division UNSTAT (1997), Etemad et al. (1991) and Mitchell (1992, 1993, 1995). The inventories use emission factors variable over time, which have been determined according to changes in technological development. The results indicate that the industrialisation period since 1860 was accompanied by a steady increase in black carbon (BC) and primary organic carbon (POC) emissions up to 1910. The calculations show a moderate decrease of carbonaceous aerosol emissions between 1920 and 1930, followed by an increase up to 1990, the year when emissions began to decrease again. Changes in BC and POC emissions prior to the year 1950 are essentially driven by the USA, Germany and the UK. The USSR, China and India become substantial contributors to carbonaceous aerosol emissions after 1950. Emission maps have been generated with a 1°×1° resolution based on the relative population density in each country. They will provide a helpful tool for assessing the effect of carbonaceous aerosol emissions on observed climate changes of the past.

  15. Development of An Ion-Drift Time-of-Flight Chemical Ionization Mass Spectrometry Technique for Measurements of Aerosol Precursor Gases

    NASA Astrophysics Data System (ADS)

    Zheng, J.; Ma, Y.; Chen, M.

    2012-12-01

    We have developed a new technique, i.e., ion-drift time-of-flight chemical ionization mass spectrometry (ID-ToF-CIMS) for measurements of aerosol precursor gases, including ammonia, amines, organic acids and oxygenated VOCs at pptv level with a response time less than 1 s. The ID-ToF-CIMS was modified from an Aerodyne high resolution ToF-CIMS with a custom-designed ion-drift tube, which can control the ion flight velocity and hence the ion-molecular reaction time. In addition, the tunable electric field generated by the drift tube can break up water clusters to select the major reagent ions. The advantages of the ID-ToF-CIMS over the traditional quadrupole-based ID-CIMS were the high mass-resolving power of the ToF mass analyzer and the capability of simultaneous measurement of the full mass range (typically up to 300 m/z) of product ions. Using hydronium ion based reagent ions, we demonstrated that the ID-ToF-CIMS can unambiguously measure ammonia (NH3) at 18.03 m/z, methyl amine (CH3NH2) at 32.05 m/z, formic acid (HCOOH) at 47.01 m/z and acetone (CH3COCH3) at 59.05 m/z. Calibrations were performed with both compressed commercial standard gases and permeation tubes and the results showed that the instrument detection limit can reach pptv level for 1 s average time or less. The ID-ToF-CIMS was also field tested in a mobile laboratory on the campus of Nanjing University of Information Science & Technology (NUIST). The preliminary results will be discussed.

  16. Fast oxidation processes from emission to ambient air introduction of aerosol emitted by residential log wood stoves

    NASA Astrophysics Data System (ADS)

    Nalin, Federica; Golly, Benjamin; Besombes, Jean-Luc; Pelletier, Charles; Aujay-Plouzeau, Robin; Verlhac, Stéphane; Dermigny, Adrien; Fievet, Amandine; Karoski, Nicolas; Dubois, Pascal; Collet, Serge; Favez, Olivier; Albinet, Alexandre

    2016-10-01

    Little is known about the impact of post-combustion processes, condensation and dilution, on the aerosol concentration and chemical composition from residential wood combustion. The evolution of aerosol emitted by two different residential log wood stoves (old and modern technologies) from emission until it is introduced into ambient air was studied under controlled "real" conditions. The first objective of this research was to evaluate the emission factors (EF) of polycyclic aromatic hydrocarbons (PAH) and their nitrated and oxygenated derivatives from wood combustion. These toxic substances are poorly documented in the literature. A second objective was to evaluate the oxidation state of the wood combustion effluent by studying these primary/secondary compounds. EFs of Σ37PAHs and Σ27Oxy-PAHs were in the same range and similar to those reported in literature (4-240 mg kg-1). Σ31Nitro-PAH EFs were 2-4 orders of magnitude lower (3.10-2-8.10-2 mg kg-1) due to the low temperature and low emission of NO2 from wood combustion processes. An increase of equivalent EF of PAH derivatives was observed suggesting that the oxidation state of the wood combustion effluent from the emission point until its introduction in ambient air changed in a few seconds. These results were confirmed by the study of both, typical compounds of SOA formation from PAH oxidation and, PAH ratio-ratio plots commonly used for source evaluation.

  17. Megacity emission plume characteristics in summer and winter investigated by mobile aerosol and trace gas measurements: the Paris metropolitan area

    NASA Astrophysics Data System (ADS)

    von der Weiden-Reinmüller, S.-L.; Drewnick, F.; Zhang, Q. J.; Freutel, F.; Beekmann, M.; Borrmann, S.

    2014-12-01

    For the investigation of megacity emission plume characteristics mobile aerosol and trace gas measurements were carried out in the greater Paris region in July 2009 and January-February 2010 within the EU FP7 MEGAPOLI project (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation). The deployed instruments measured physical and chemical properties of sub-micron aerosol particles, gas phase constituents of relevance for urban air pollution studies and meteorological parameters. The emission plume was identified based on fresh pollutant (e.g., particle-bound polycyclic aromatic hydrocarbons, black carbon, CO2 and NOx) concentration changes in combination with wind direction data. The classification into megacity influenced and background air masses allowed a characterization of the emission plume during summer and winter environmental conditions. On average, a clear increase of fresh pollutant concentrations in plume compared to background air masses was found for both seasons. For example, an average increase of 190% (+ 8.8 ng m-3) in summer and of 130% (+ 18.1 ng m-3) in winter was found for particle-bound polycyclic aromatic hydrocarbons in plume air masses. The aerosol particle size distribution in plume air masses was influenced by nucleation and growth due to coagulation and condensation in summer, while in winter only the latter process (i.e., particle growth) seemed to be initiated by urban pollution. The observed distribution of fresh pollutants in the emission plume - its cross sectional Gaussian-like profile and the exponential decrease of pollutant concentrations with increasing distance to the megacity - are in agreement with model results. Differences between model and measurements were found for plume center location, plume width and axial plume extent. In general, dilution was identified as the dominant process determining the axial variations within the Paris

  18. The impact of bark beetle infestations on monoterpene emissions and secondary organic aerosol formation in western North America

    NASA Astrophysics Data System (ADS)

    Berg, A. R.; Heald, C. L.; Huff Hartz, K. E.; Hallar, A. G.; Meddens, A. J. H.; Hicke, J. A.; Lamarque, J.-F.; Tilmes, S.

    2013-03-01

    Over the last decade, extensive beetle outbreaks in western North America have destroyed over 100 000 km2 of forest throughout British Columbia and the western United States. Beetle infestations impact monoterpene emissions through both decreased emissions as trees are killed (mortality effect) and increased emissions in trees under attack (attack effect). We use 14 yr of beetle-induced tree mortality data together with beetle-induced monoterpene emission data in the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM) to investigate the impact of beetle-induced tree mortality and attack on monoterpene emissions and secondary organic aerosol (SOA) formation in western North America. Regionally, beetle infestations may have a significant impact on monoterpene emissions and SOA concentrations, with up to a 4-fold increase in monoterpene emissions and up to a 40% increase in SOA concentrations in some years (in a scenario where the attack effect is based on observed lodgepole pine response). Responses to beetle attack depend on the extent of previous mortality and the number of trees under attack in a given year, which can vary greatly over space and time. Simulated enhancements peak in 2004 (British Columbia) and 2008 (US). Responses to beetle attack are shown to be substantially larger (up to a 3-fold localized increase in summertime SOA concentrations) in a scenario based on bark-beetle attack in spruce trees. Placed in the context of observations from the IMPROVE network, the changes in SOA concentrations due to beetle attack are in most cases small compared to the large annual and interannual variability in total organic aerosol which is driven by wildfire activity in western North America. This indicates that most beetle-induced SOA changes are not likely detectable in current observation networks; however, these changes may impede efforts to achieve natural visibility conditions in the national parks and wilderness areas of the

  19. Effect of Hydrophobic Primary Organic Aerosols on Secondary Organic Aerosol Formation from Ozonolysis of α-Pinene

    SciTech Connect

    Song, Chen; Zaveri, Rahul A.; Alexander, M. Lizabeth; Thornton, Joel A.; Madronich, Sasha; Ortega, John V.; Zelenyuk, Alla; Yu, Xiao-Ying; Laskin, Alexander; Maughan, A. D.

    2007-10-16

    Semi-empirical secondary organic aerosol (SOA) models typically assume a well-mixed organic aerosol phase even in the presence of hydrophobic primary organic aerosols (POA). This assumption significantly enhances the modeled SOA yields as additional organic mass is made available to absorb greater amounts of oxidized secondary organic gases than otherwise. We investigate the applicability of this critical assumption by measuring SOA yields from ozonolysis of α-pinene (a major biogenic SOA precursor) in a smog chamber in the absence and in the presence of dioctyl phthalate (DOP) and lubricating oil seed aerosol. These particles serve as surrogates for urban hydrophobic POA. The results show that these POA did not enhance the SOA yields. If these results are found to apply to other biogenic SOA precursors, then the semi-empirical models used in many global models would predict significantly less biogenic SOA mass and display reduced sensitivity to anthropogenic POA emissions than previously thought.

  20. Internal Energy Dissipation of Gamma-Ray Bursts Observed with Swift: Precursors, Prompt Gamma-Rays, Extended Emission, and Late X-Ray Flares

    NASA Astrophysics Data System (ADS)

    Hu, You-Dong; Liang, En-Wei; Xi, Shao-Qiang; Peng, Fang-Kun; Lu, Rui-Jing; Lü, Lian-Zhong; Zhang, Bing

    2014-07-01

    We jointly analyze the gamma-ray burst (GRB) data observed with Burst Alert Telescope (BAT) and X-ray Telescope on board the Swift mission to present a global view on the internal energy dissipation processes in GRBs, including precursors, prompt gamma-ray emission, extended soft gamma-ray emission, and late X-ray flares. The Bayesian block method is utilized to analyze the BAT light curves to identify various emission episodes. Our results suggest that these emission components likely share the same physical origin, which is the repeated activation of the GRB central engine. What we observe in the gamma-ray band may be a small part of more extended underlying activities. The precursor emission, which is detected in about 10% of Swift GRBs, is preferably detected in those GRBs that have a massive star core-collapse origin. The soft extended emission tail, on the other hand, is preferably detected in those GRBs that have a compact star merger origin. Bright X-ray emission is detected during the BAT quiescent phases prior to subsequent gamma-ray peaks, implying that X-ray emission may be detectable prior the BAT trigger time. Future GRB alert instruments with soft X-ray capability are essential for revealing the early stages of GRB central engine activities, and shedding light on jet composition and the jet launching mechanism in GRBs.

  1. Internal energy dissipation of gamma-ray bursts observed with Swift: Precursors, prompt gamma-rays, extended emission, and late X-ray flares

    SciTech Connect

    Hu, You-Dong; Liang, En-Wei; Xi, Shao-Qiang; Peng, Fang-Kun; Lu, Rui-Jing; Lü, Lian-Zhong; Zhang, Bing E-mail: Zhang@physics.unlv.edu

    2014-07-10

    We jointly analyze the gamma-ray burst (GRB) data observed with Burst Alert Telescope (BAT) and X-ray Telescope on board the Swift mission to present a global view on the internal energy dissipation processes in GRBs, including precursors, prompt gamma-ray emission, extended soft gamma-ray emission, and late X-ray flares. The Bayesian block method is utilized to analyze the BAT light curves to identify various emission episodes. Our results suggest that these emission components likely share the same physical origin, which is the repeated activation of the GRB central engine. What we observe in the gamma-ray band may be a small part of more extended underlying activities. The precursor emission, which is detected in about 10% of Swift GRBs, is preferably detected in those GRBs that have a massive star core-collapse origin. The soft extended emission tail, on the other hand, is preferably detected in those GRBs that have a compact star merger origin. Bright X-ray emission is detected during the BAT quiescent phases prior to subsequent gamma-ray peaks, implying that X-ray emission may be detectable prior the BAT trigger time. Future GRB alert instruments with soft X-ray capability are essential for revealing the early stages of GRB central engine activities, and shedding light on jet composition and the jet launching mechanism in GRBs.

  2. Characterization of submicron particles influenced by mixed biogenic and anthropogenic emissions using high-resolution aerosol mass spectrometry: results from CARES

    SciTech Connect

    Setyan, Ari; Zhang, Qi; Merkel, M.; Knighton, Walter B.; Sun, Y.; Song, Chen; Shilling, John E.; Onasch, Timothy B.; Herndon, Scott C.; Worsnop, Douglas R.; Fast, Jerome D.; Zaveri, Rahul A.; Berg, Larry K.; Wiedensohler, A.; Flowers, B. A.; Dubey, Manvendra K.; Subramanian, R.

    2012-09-11

    The Carbonaceous Aerosols and Radiative Effects Study (CARES) took place in the Sacramento Valley of California in summer 2010. We present results obtained at Cool, CA, the T1 site of the project ({approx}40 km downwind of urban emissions from Sacramento), where we deployed an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) in parallel with complementary instrumentation to characterize the sources and processes of submicron particles (PM1). Cool is located at the foothill of the Sierra Nevada Mountains, where intense biogenic emissions are periodically mixed with urban outflow transported by daytime southwesterly winds from the Sacramento metropolitan area. The particle mass loading was low (3.0 {micro}gm{sup -3} on average) and dominated by organics (80% of the PM1 mass) followed by sulfate (9.9 %). Organics and sulfate appeared to be externally mixed, as suggested by their different time series (r2 = 0.13) and size distributions. Sulfate showed a bimodal distribution with a droplet mode peaking at {approx}400nm in vacuum aerodynamic diameter (Dva), and a condensation mode at {approx}150 nm, while organics generally displayed a broad distribution in 60-600nm (Dva). New particle formation and growth events were observed almost every day, emphasizing the roles of organics and sulfate in new particle growth, especially that of organics. The organic aerosol (OA) had a nominal formula of C{sub 1}H{sub 1.38}N{sub 0.004}O{sub 0.44}, thus an average organic mass-to-carbon (OM/OC) ratio of 1.70. Two different oxygenated OA (OOA, 90% of total OA mass) and a hydrocarbon-like OA (HOA, 10 %) were identified by Positive matrix factorization (PMF) of the high resolution mass spectra. The more oxidized MO-OOA (O/C = 0.54) corresponded to secondary OA (SOA) primarily influenced by biogenic emissions, while the less oxidized LO-OOA (O/C = 0.42) corresponded to SOA associated with urban transport. The HOA factor corresponded to primary emissions mainly

  3. Black carbon in aerosol during BIBLE B

    NASA Astrophysics Data System (ADS)

    Liley, J. Ben; Baumgardner, D.; Kondo, Y.; Kita, K.; Blake, D. R.; Koike, M.; Machida, T.; Takegawa, N.; Kawakami, S.; Shirai, T.; Ogawa, T.

    2003-02-01

    The Biomass Burning and Lightning Experiment (BIBLE) A and B campaigns over the tropical western Pacific during springtime deployed a Gulfstream-II aircraft with systems to measure ozone and numerous precursor species. Aerosol measuring systems included a MASP optical particle counter, a condensation nucleus (CN) counter, and an absorption spectrometer for black carbon. Aerosol volume was very low in the middle and upper troposphere during both campaigns, and during BIBLE A, there was little aerosol enhancement in the boundary layer away from urban areas. In BIBLE B, there was marked aerosol enhancement in the lowest 3 km of the atmosphere. Mixing ratios of CN in cloud-free conditions in the upper troposphere were in general higher than in the boundary layer, indicating new particle formation from gaseous precursors. High concentrations of black carbon were observed during BIBLE B, with mass loadings up to 40 μg m-3 representing as much as one quarter of total aerosol mass. Strong correlations with hydrocarbon enhancement allow the determination of a black carbon emission ratio for the fires at that time. Expressed as elemental carbon, it is about 0.5% of carbon dioxide and 6% of carbon monoxide emissions from the same fires, comparable to methane production, and greater than that of other hydrocarbons.

  4. Black carbon in aerosol during BIBLE B

    NASA Astrophysics Data System (ADS)

    Liley, J. Ben; Baumgardner, D.; Kondo, Y.; Kita, K.; Blake, D. R.; Koike, M.; Machida, T.; Takegawa, N.; Kawakami, S.; Shirai, T.; Ogawa, T.

    2002-02-01

    The Biomass Burning and Lightning Experiment (BIBLE) A and B campaigns over the tropical western Pacific during springtime deployed a Gulfstream-II aircraft with systems to measure ozone and numerous precursor species. Aerosol measuring systems included a MASP optical particle counter, a condensation nucleus (CN) counter, and an absorption spectrometer for black carbon. Aerosol volume was very low in the middle and upper troposphere during both campaigns, and during BIBLE A, there was little aerosol enhancement in the boundary layer away from urban areas. In BIBLE B, there was marked aerosol enhancement in the lowest 3 km of the atmosphere. Mixing ratios of CN in cloud-free conditions in the upper troposphere were in general higher than in the boundary layer, indicating new particle formation from gaseous precursors. High concentrations of black carbon were observed during BIBLE B, with mass loadings up to 40 μg m-3 representing as much as one quarter of total aerosol mass. Strong correlations with hydrocarbon enhancement allow the determination of a black carbon emission ratio for the fires at that time. Expressed as elemental carbon, it is about 0.5% of carbon dioxide and 6% of carbon monoxide emissions from the same fires, comparable to methane production, and greater than that of other hydrocarbons.

  5. Fluxes of reactive trace gases from Tapajos forest: Upwind precursor emissions to complement the GoAmazon campaign.

    NASA Astrophysics Data System (ADS)

    Munger, J. W.; Alves, E. G.; Batalha, S. S. A.; Freitas, H.; Guenther, A. B.; Hayek, M.; Martin, S. T.; Park, J. H.; Rizzo, L. V.; Rocha, H.; Saleska, S. R.; Seco, R.; Smith, J. N.; Tota, J.; Wiedemann, K. T.; Wofsy, S. C.

    2014-12-01

    The Amazon Forest includes a diverse combination of vegetation characteristics, climate, and land usage that influence emission of the reactive trace-gases driving atmospheric chemistry and particle formation. A better understanding of atmospheric chemistry across this region requires consideration of variation in precursor emissions. To complement the intensive GoAmazon measurement campaigns that are focused on the interaction of Manaus urban plume with surrounding forest emissions we have established a suite of measurements at the km67 site in the Floresta Nacional do Tapajós, south of Santarem. The site is situated midway between the Tapajos River on the west and the BR 163 highway to the east (upwind). The nearby surroundings for up to 6 km on all sides is intact rain forest. A strip along the east side of the highway and adjacent roads has been cleared for agriculture, but the upwind area is otherwise sparsely populated. The km67 site was initially established in 2001 during the LBA campaign as carbon flux site and included CO measurements to identify influence from local and regional biomass burning. A 64 m tower extends above a 40-45 m closed canopy. In 2014 additional instrumentation including continuous NO/NO2, O3, SO2, and CH4 concentration profiles, NOy concentration and fluxes were added. Volatile organic compound (VOC) measurements using a PTR-HRTOF-MS (Proton Transfer Reaction-High Resolution-Time of Flight-Mass Spectrometer) and particle measurements using a nanoSMPS were added during a campaign in June-July 2014. This period was influenced by heavy precipitation; as a result O3 levels above the canopy were rather low, and declined further close to the ground. Even though there was no evidence of anthropogenic influence NO and NO2 concentrations were significant. Elevated concentrations beneath the canopy indicate soil NO emission is the dominant source. Eddy-covariance flux measurements of volatile organic compounds (VOC) above the Tapajós forest

  6. Evolved gas analysis of secondary organic aerosols

    SciTech Connect

    Grosjean, D.; Williams, E.L. II; Grosjean, E. ); Novakov, T. )

    1994-11-01

    Secondary organic aerosols have been characterized by evolved gas analysis (EGA). Hydrocarbons selected as aerosol precursors were representative of anthropogenic emissions (cyclohexene, cyclopentene, 1-decene and 1-dodecene, n-dodecane, o-xylene, and 1,3,5-trimethylbenzene) and of biogenic emissions (the terpenes [alpha]-pinene, [beta]-pinene and d-limonene and the sesquiterpene trans-caryophyllene). Also analyzed by EGA were samples of secondary, primary (highway tunnel), and ambient (urban) aerosols before and after exposure to ozone and other photochemical oxidants. The major features of the EGA thermograms (amount of CO[sub 2] evolved as a function of temperature) are described. The usefulness and limitations of EGA data for source apportionment of atmospheric particulate carbon are briefly discussed. 28 refs., 7 figs., 4 tabs.

  7. Megacity emission plume characteristics in summer and winter investigated by mobile aerosol and trace gas measurements: the Paris metropolitan area

    NASA Astrophysics Data System (ADS)

    von der Weiden-Reinmüller, S.-L.; Drewnick, F.; Zhang, Q. J.; Freutel, F.; Beekmann, M.; Borrmann, S.

    2014-05-01

    For the investigation of megacity emission plume characteristics mobile aerosol and trace gas measurements were carried out in the greater Paris region in July 2009 and January/February 2010 within the EU FP7 MEGAPOLI project. The deployed instruments measured physical and chemical properties of sub-micron aerosol particles, gas phase constituents of relevance for urban air pollution studies and meteorological parameters. The emission plume was identified based on fresh pollutant (e.g. particle-bound polycyclic aromatic hydrocarbons, black carbon, CO2 and NOx) concentration changes in combination with wind direction data. The classification into megacity influenced and background air masses allowed a characterization of the emission plume during summer and winter environmental conditions. On average, a clear increase of fresh pollutant concentrations in plume compared to background air masses was found for both seasons. For example, an average increase of 190% (+8.8 ng m-3) in summer and of 130% (+18.1 ng m-3) in winter was found for particle-bound polycyclic aromatic hydrocarbons in plume air masses. The aerosol particle size distribution in plume air masses was influenced by nucleation and growth due to coagulation and condensation in summer, while in winter only the second process seemed to be initiated by urban pollution. The observed distribution of fresh pollutants in the emission plume - its cross sectional Gaussian-like profile and the exponential decrease of pollutant concentrations with increasing distance to the megacity - are in agreement with model results. Differences between model and measurements were found for plume center location, plume width and axial plume extent. In general, dilution was identified as the dominant process determining the axial variations within the Paris emission plume. For in-depth analysis of transformation processes occurring in the advected plume, simultaneous measurements at a suburban measurement site and a stationary

  8. Complex Coupling of Air Quality and Climate-Relevant Aerosols in a Chemistry-Aerosol Microphysics Model

    NASA Astrophysics Data System (ADS)

    Yoshioka, M.; Carslaw, K. S.; Reddington, C.; Mann, G.

    2013-12-01

    Controlling emissions of aerosols and their precursors to improve air quality will impact the climate through direct and indirect radiative forcing. We have investigated the impacts of changes in a range of aerosol and gas-phase emission fluxes and changes in temperature on air quality and climate change metrics using a global aerosol microphysics and chemistry model, GLOMAP. We investigate how the responses of PM2.5 and cloud condensation nuclei (CCN) are coupled, and how attempts to improve air quality could have inadvertent effects on CCN, clouds and climate. The parameter perturbations considered are a 5°C increase in global temperature, increased or decreased precursor emissions of anthropogenic SO2, NH3, and NOx, and biogenic monoterpenes, and increased or decreased primary emissions of organic and black carbon aerosols from wildfire, fossil fuel, and biofuel. To quantify the interactions, we define a new sensitivity metric in terms of the response of CCN divided by the response of PM in different regions. .Our results show that the coupled chemistry and aerosol processes cause complex responses that will make any co-benefit policy decision problematic. In particular, we show that reducing SO2 emissions effectively reduces surface-level PM2.5 over continental regions in summer when background PM2.5 is high, with a relatively small reduction in marine CCN (and hence indirect radiative cooling over ocean), which is beneficial for near-term climate. Reducing NOx emissions does not improve summertime air quality very effectively but leads to a relatively high reduction of marine CCN. Reducing NH3 emissions has moderate effects on both PM2.5 and CCN. These three species are strongly coupled chemically and microphysically and the effects of changing emissions of one species on mass and size distributions of aerosols are very complex and spatially and temporally variable. For example, reducing SO2 emissions leads to reductions in sulphate and ammonium mass

  9. Influences of emission sources and meteorology on aerosol chemistry in a polluted urban environment: results from DISCOVER-AQ California

    NASA Astrophysics Data System (ADS)

    Young, D. E.; Kim, H.; Parworth, C.; Zhou, S.; Zhang, X.; Cappa, C. D.; Seco, R.; Kim, S.; Zhang, Q.

    2015-12-01

    The San Joaquin Valley (SJV) in California experiences persistent air quality problems associated with elevated particulate matter (PM) concentrations due to anthropogenic emissions, topography, and meteorological conditions. Thus it is important to unravel the various sources and processes that affect the physico-chemical properties of PM in order to better inform pollution abatement strategies and improve parameterizations in air quality models. Aerosol Mass Spectrometer (HR-ToF-AMS) and an Ionicon Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-TOF-MS) as part of the NASA Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) campaign. The average submicron aerosol (PM1) concentration was 31.0 μg m-3 and the total mass was dominated by organic aerosols (OA, 55 %), followed by ammonium nitrate (35 %). High PM pollution events were commonly associated with elevated OA concentrations, mostly from primary sources. Organic aerosols had average atomic oxygen-to-carbon (O / C), hydrogen-to-carbon (H / C), and nitrogen-to-carbon (N / C) ratios of 0.42, 1.70, and 0.017, respectively. Six distinct sources of organic aerosol were identified from positive matrix factorization (PMF) analysis of the AMS data: hydrocarbon-like OA (HOA; 9 % of total OA; O / C = 0.09) associated with local traffic, cooking OA (COA; 28 % of total OA; O / C = 0.19) associated with food cooking activities, two biomass burning OAs (BBOA1; 13 % of total OA; O / C = 0.33 and BBOA2; 20 % of total OA; O / C = 0.60) most likely associated with residential space heating from wood combustion, and semi

  10. Influences of emission sources and meteorology on aerosol chemistry in a polluted urban environment: results from DISCOVER-AQ California

    DOE PAGES

    Young, Dominique E.; Kim, Hwajin; Parworth, Caroline; ...

    2016-05-02

    The San Joaquin Valley (SJV) in California experiences persistent air-quality problems associated with elevated particulate matter (PM) concentrations due to anthropogenic emissions, topography, and meteorological conditions. Thus it is important to unravel the various sources and processes that affect the physicochemical properties of PM in order to better inform pollution abatement strategies and improve parameterizations in air-quality models. During January and February 2013, a ground supersite was installed at the Fresno–Garland California Air Resources Board (CARB) monitoring station, where comprehensive, real-time measurements of PM and trace gases were performed using instruments including an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) andmore » an Ionicon proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) as part of the NASA Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) campaign. The average submicron aerosol (PM1) concentration was 31.0 µg m−3 and the total mass was dominated by organic aerosols (OA, 55 %), followed by ammonium nitrate (35 %). High PM pollution events were commonly associated with elevated OA concentrations, mostly from primary sources. Organic aerosols had average atomic oxygen-to-carbon (O / C), hydrogen-to-carbon (H / C), and nitrogen-to-carbon (N / C) ratios of 0.42, 1.70, and 0.017, respectively. Six distinct sources of organic aerosol were identified from positive matrix factorization (PMF) analysis of the AMS data: hydrocarbon-like OA (HOA; 9 % of total OA, O / C  =  0.09) associated with local traffic, cooking OA (COA; 18 % of total OA, O / C  =  0.19) associated with food cooking activities, two biomass burning OA (BBOA1: 13 % of total OA, O / C  =  0.33; BBOA2: 20 % of total OA, O / C  =  0.60) most likely

  11. Influences of emission sources and meteorology on aerosol chemistry in a polluted urban environment: results from DISCOVER-AQ California

    NASA Astrophysics Data System (ADS)

    Young, Dominique E.; Kim, Hwajin; Parworth, Caroline; Zhou, Shan; Zhang, Xiaolu; Cappa, Christopher D.; Seco, Roger; Kim, Saewung; Zhang, Qi

    2016-05-01

    The San Joaquin Valley (SJV) in California experiences persistent air-quality problems associated with elevated particulate matter (PM) concentrations due to anthropogenic emissions, topography, and meteorological conditions. Thus it is important to unravel the various sources and processes that affect the physicochemical properties of PM in order to better inform pollution abatement strategies and improve parameterizations in air-quality models. During January and February 2013, a ground supersite was installed at the Fresno-Garland California Air Resources Board (CARB) monitoring station, where comprehensive, real-time measurements of PM and trace gases were performed using instruments including an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and an Ionicon proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) as part of the NASA Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) campaign. The average submicron aerosol (PM1) concentration was 31.0 µg m-3 and the total mass was dominated by organic aerosols (OA, 55 %), followed by ammonium nitrate (35 %). High PM pollution events were commonly associated with elevated OA concentrations, mostly from primary sources. Organic aerosols had average atomic oxygen-to-carbon (O / C), hydrogen-to-carbon (H / C), and nitrogen-to-carbon (N / C) ratios of 0.42, 1.70, and 0.017, respectively. Six distinct sources of organic aerosol were identified from positive matrix factorization (PMF) analysis of the AMS data: hydrocarbon-like OA (HOA; 9 % of total OA, O / C = 0.09) associated with local traffic, cooking OA (COA; 18 % of total OA, O / C = 0.19) associated with food cooking activities, two biomass burning OA (BBOA1: 13 % of total OA, O / C = 0.33; BBOA2: 20 % of total OA, O / C = 0.60) most likely associated with residential space heating from wood combustion, and semivolatile oxygenated OA (SV

  12. Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA)—Power plant studies: assessment of breathing pattern

    PubMed Central

    Diaz, Edgar A.; Lemos, Miriam; Coull, Brent; Long, Mark S.; Rohr, Annette C.; Ruiz, Pablo; Gupta, Tarun; Kang, Choong-Min; Godleski, John J.

    2013-01-01

    Our approach to study multi-pollutant aerosols isolates a single emissions source, evaluates the toxicity of primary and secondary particles derived from this source, and simulates chemical reactions that occur in the atmosphere after emission. Three U.S. coal-fired power plants utilizing different coals and with different emission controls were evaluated. Secondary organic aerosol (SOA) derived from α-pinene and/or ammonia was added in some experiments. Male Sprague-Dawley rats were exposed for 6 h to filtered air or different atmospheric mixtures. Scenarios studied at each plant included the following: primary particles (P); secondary (oxidized) particles (PO); oxidized particles + SOA (POS); and oxidized and neutralized particles + SOA (PONS); additional control scenarios were also studied. Continuous respiratory data were obtained during exposures using whole body plethysmography chambers. Of the 12 respiratory outcomes assessed, each had statistically significant changes at some plant and with some of the 4 scenarios. The most robust outcomes were found with exposure to the PO scenario (increased respiratory frequency with decreases in inspiratory and expiratory time); and the PONS scenario (decreased peak expiratory flow and expiratory flow at 50%). PONS findings were most strongly associated with ammonium, neutralized sulfate, and elemental carbon (EC) in univariate analyses, but only with EC in multivariate analyses. Control scenario O (oxidized without primary particles) had similar changes to PO. Adjusted R2 analyses showed that scenario was a better predictor of respiratory responses than individual components, suggesting that the complex atmospheric mixture was responsible for respiratory effects. PMID:21639693

  13. Production-based emissions, consumption-based emissions and consumption-based health impacts of PM2.5 carbonaceous aerosols in Asia

    NASA Astrophysics Data System (ADS)

    Takahashi, Kei; Nansai, Keisuke; Tohno, Susumu; Nishizawa, Masato; Kurokawa, Jun-ichi; Ohara, Toshimasa

    2014-11-01

    This study determined the production-based emissions, the consumption-based emissions, and the consumption-based health impact of primary carbonaceous aerosols (black carbon: BC, organic carbon: OC) in nine countries and regions in Asia (Indonesia, Malaysia, the Philippines, Singapore, Thailand, China, Taiwan, South Korea, and Japan) in 2008. For the production-based emissions, sectoral emissions inventory of BC and OC for the year of 2008 based on the Asian international input-output tables (AIIOT) was compiled including direct emissions from households. Then, a multiregional environmental input-output analysis with the 2008 AIIOT which was originally developed by updating the table of 2000 was applied for calculating the consumption-based emissions for each country and region. For the production-based emissions, China had the highest BC and OC emissions of 4520 Gg-C in total, which accounted for 75% of the total emissions in the nine countries and regions. For consumption-based emissions, China was estimated to have had a total of 4849 Gg-C of BC and OC emissions, which accounted for 77% of the total emissions in the Asia studied. We also quantified how much countries and regions induced emissions in other countries and regions. Furthermore, taking account of the source-receptor relationships of BC and OC among the countries and regions, we converted their consumption-based emissions into the consumption-based health impact of each country and region. China showed the highest consumption-based health impact of BC and OC totaling 111 × 103 premature deaths, followed by Indonesia, Japan, Thailand and South Korea. China accounted for 87% of the sum total of the consumption-based health impacts of the countries/regions, indicating that China's contribution to consumption-based health impact in Asia was greater than its consumption-based emissions. By elucidating the health impacts that each country and region had on other countries and from which country the impacts

  14. Satellite Perspective of Aerosol Intercontinental Transport: From Qualitative Tracking to Quantitative Characterization

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Remer, Lorraine A.; Kahn, Ralph A.; Chin, Mian; Zhang, Yan

    2012-01-01

    Evidence of aerosol intercontinental transport (ICT) is both widespread and compelling. Model simulations suggest that ICT could significantly affect regional air quality and climate, but the broad inter-model spread of results underscores a need of constraining model simulations with measurements. Satellites have inherent advantages over in situ measurements to characterize aerosol ICT, because of their spatial and temporal coverage. Significant progress in satellite remote sensing of aerosol properties during the Earth Observing System (EOS) era offers opportunity to increase quantitative characterization and estimates of aerosol ICT, beyond the capability of pre-EOS era satellites that could only qualitatively track aerosol plumes. EOS satellites also observe emission strengths and injection heights of some aerosols, aerosol precursors, and aerosol-related gases, which can help characterize aerosol ICT. After an overview of these advances, we review how the current generation of satellite measurements have been used to (1) characterize the evolution of aerosol plumes (e.g., both horizontal and vertical transport, and properties) on an episodic basis, (2) understand the seasonal and inter-annual variations of aerosol ICT and their control factors, (3) estimate the export and import fluxes of aerosols, and (4) evaluate and constrain model simulations. Substantial effort is needed to further explore an integrated approach using measurements from on-orbit satellites (e.g., A-Train synergy) for observational characterization and model constraint of aerosol intercontinental transport and to develop advanced sensors for future missions.

  15. Assessment of biomass burning smoke influence on environmental conditions for multiyear tornado outbreaks by combining aerosol-aware microphysics and fire emission constraints

    NASA Astrophysics Data System (ADS)

    Saide, Pablo E.; Thompson, Gregory; Eidhammer, Trude; Silva, Arlindo M.; Pierce, R. Bradley; Carmichael, Gregory R.

    2016-09-01

    We use the Weather Research and Forecasting (WRF) system to study the impacts of biomass burning smoke from Central America on several tornado outbreaks occurring in the U.S. during spring. The model is configured with an aerosol-aware microphysics parameterization capable of resolving aerosol-cloud-radiation interactions in a cost-efficient way for numerical weather prediction (NWP) applications. Primary aerosol emissions are included, and smoke emissions are constrained using an inverse modeling technique and satellite-based aerosol optical depth observations. Simulations turning on and off fire emissions reveal smoke presence in all tornado outbreaks being studied and show an increase in aerosol number concentrations due to smoke. However, the likelihood of occurrence and intensification of tornadoes is higher due to smoke only in cases where cloud droplet number concentration in low-level clouds increases considerably in a way that modifies the environmental conditions where the tornadoes are formed (shallower cloud bases and higher low-level wind shear). Smoke absorption and vertical extent also play a role, with smoke absorption at cloud-level tending to burn-off clouds and smoke absorption above clouds resulting in an increased capping inversion. Comparing these and WRF-Chem simulations configured with a more complex representation of aerosol size and composition and different optical properties, microphysics, and activation schemes, we find similarities in terms of the simulated aerosol optical depths and aerosol impacts on near-storm environments. This provides reliability on the aerosol-aware microphysics scheme as a less computationally expensive alternative to WRF-Chem for its use in applications such as NWP and cloud-resolving simulations.

  16. Multi-model simulations of aerosol and ozone radiative forcing due to anthropogenic emission changes during the period 1990-2015

    NASA Astrophysics Data System (ADS)

    Myhre, Gunnar; Aas, Wenche; Cherian, Ribu; Collins, William; Faluvegi, Greg; Flanner, Mark; Forster, Piers; Hodnebrog, Øivind; Klimont, Zbigniew; Lund, Marianne T.; Mülmenstädt, Johannes; Myhre, Cathrine Lund; Olivié, Dirk; Prather, Michael; Quaas, Johannes; Samset, Bjørn H.; Schnell, Jordan L.; Schulz, Michael; Shindell, Drew; Skeie, Ragnhild B.; Takemura, Toshihiko; Tsyro, Svetlana

    2017-02-01

    Over the past few decades, the geographical distribution of emissions of substances that alter the atmospheric energy balance has changed due to economic growth and air pollution regulations. Here, we show the resulting changes to aerosol and ozone abundances and their radiative forcing using recently updated emission data for the period 1990-2015, as simulated by seven global atmospheric composition models. The models broadly reproduce large-scale changes in surface aerosol and ozone based on observations (e.g. -1 to -3 % yr-1 in aerosols over the USA and Europe). The global mean radiative forcing due to ozone and aerosol changes over the 1990-2015 period increased by +0.17 ± 0.08 W m-2, with approximately one-third due to ozone. This increase is more strongly positive than that reported in IPCC AR5. The main reasons for the increased positive radiative forcing of aerosols over this period are the substantial reduction of global mean SO2 emissions, which is stronger in the new emission inventory compared to that used in the IPCC analysis, and higher black carbon emissions.

  17. Multi-Model Simulations of Aerosol and Ozone Radiative Forcing Due to Anthropogenic Emission Changes During the Period 1990-2015

    NASA Technical Reports Server (NTRS)

    Myhre, Gunnar; Aas, Wenche; Ribu, Cherian; Collins, William; Faluvegi, Gregory S.; Flanner, Mark; Forster, Piers; Hodnebrog, Oivind; Klimont, Zbigniew; Lund, Marianne T.

    2017-01-01

    Over the past few decades, the geographical distribution of emissions of substances that alter the atmospheric energy balance has changed due to economic growth and air pollution regulations. Here, we show the resulting changes to aerosol and ozone abundances and their radiative forcing using recently updated emission data for the period 1990-2015, as simulated by seven global atmospheric composition models. The models broadly reproduce large-scale changes in surface aerosol and ozone based on observations (e.g. 1 to 3 percent per year in aerosols over the USA and Europe). The global mean radiative forcing due to ozone and aerosol changes over the 1990-2015 period increased by 0.17 plus or minus 0.08 watts per square meter, with approximately one-third due to ozone. This increase is more strongly positive than that reported in IPCC AR5 (Intergovernmental Panel on Climate Change Fifth Assessment Report). The main reasons for the increased positive radiative forcing of aerosols over this period are the substantial reduction of global mean SO2 emissions, which is stronger in the new emission inventory compared to that used in the IPCC analysis, and higher black carbon emissions.

  18. Fossil Fuel Combustion-Related Emissions Dominate Atmospheric Ammonia Sources during Severe Haze Episodes: Evidence from (15)N-Stable Isotope in Size-Resolved Aerosol Ammonium.

    PubMed

    Pan, Yuepeng; Tian, Shili; Liu, Dongwei; Fang, Yunting; Zhu, Xiaying; Zhang, Qiang; Zheng, Bo; Michalski, Greg; Wang, Yuesi

    2016-08-02

    The reduction of ammonia (NH3) emissions is urgently needed due to its role in aerosol nucleation and growth causing haze formation during its conversion into ammonium (NH4(+)). However, the relative contributions of individual NH3 sources are unclear, and debate remains over whether agricultural emissions dominate atmospheric NH3 in urban areas. Based on the chemical and isotopic measurements of size-resolved aerosols in urban Beijing, China, we find that the natural abundance of (15)N (expressed using δ(15)N values) of NH4(+) in fine particles varies with the development of haze episodes, ranging from -37.1‰ to -21.7‰ during clean/dusty days (relative humidity: ∼ 40%), to -13.1‰ to +5.8‰ during hazy days (relative humidity: 70-90%). After accounting for the isotope exchange between NH3 gas and aerosol NH4(+), the δ(15)N value of the initial NH3 during hazy days is found to be -14.5‰ to -1.6‰, which indicates fossil fuel-based emissions. These emissions contribute 90% of the total NH3 during hazy days in urban Beijing. This work demonstrates the analysis of δ(15)N values of aerosol NH4(+) to be a promising new tool for partitioning atmospheric NH3 sources, providing policy makers with insights into NH3 emissions and secondary aerosols for regulation in urban environments.

  19. Herbivory by an Outbreaking Moth Increases Emissions of Biogenic Volatiles and Leads to Enhanced Secondary Organic Aerosol Formation Capacity.

    PubMed

    Yli-Pirilä, Pasi; Copolovici, Lucian; Kännaste, Astrid; Noe, Steffen; Blande, James D; Mikkonen, Santtu; Klemola, Tero; Pulkkinen, Juha; Virtanen, Annele; Laaksonen, Ari; Joutsensaari, Jorma; Niinemets, Ülo; Holopainen, Jarmo K

    2016-11-01

    In addition to climate warming, greater herbivore pressure is anticipated to enhance the emissions of climate-relevant biogenic volatile organic compounds (VOCs) from boreal and subarctic forests and promote the formation of secondary aerosols (SOA) in the atmosphere. We evaluated the effects of Epirrita autumnata, an outbreaking geometrid moth, feeding and larval density on herbivore-induced VOC emissions from mountain birch in laboratory experiments and assessed the impact of these emissions on SOA formation via ozonolysis in chamber experiments. The results show that herbivore-induced VOC emissions were strongly dependent on larval density. Compared to controls without larval feeding, clear new particle formation by nucleation in the reaction chamber was observed, and the SOA mass loadings in the insect-infested samples were significantly higher (up to 150-fold). To our knowledge, this study provides the first controlled documentation of SOA formation from direct VOC emission of deciduous trees damaged by known defoliating herbivores and suggests that chewing damage on mountain birch foliage could significantly increase reactive VOC emissions that can importantly contribute to SOA formation in subarctic forests. Additional feeding experiments on related silver birch confirmed the SOA results. Thus, herbivory-driven volatiles are likely to play a major role in future biosphere-vegetation feedbacks such as sun-screening under daily 24 h sunshine in the subarctic.

  20. The economics and ethics of aerosol geoengineering strategies

    NASA Astrophysics Data System (ADS)

    Goes, Marlos; Keller, Klaus; Tuana, Nancy

    2010-05-01

    Anthropogenic greenhouse gas emissions are changing the Earth's climate and impose substantial risks for current and future generations. What are scientifically sound, economically viable, and ethically defendable strategies to manage these climate risks? Ratified international agreements call for a reduction of greenhouse gas emissions to avoid dangerous anthropogenic interference with the climate system. Recent proposals, however, call for a different approach: geoengineering climate by injecting aerosol precursors into the stratosphere. Published economic studies typically neglect the risks of aerosol geoengineering due to (i) a potential failure to sustain the aerosol forcing and (ii) due to potential negative impacts associated with aerosol forcings. Here we use a simple integrated assessment model of climate change to analyze potential economic impacts of aerosol geoengineering strategies over a wide range of uncertain parameters such as climate sensitivity, the economic damages due to climate change, and the economic damages due to aerosol geoengineering forcings. The simplicity of the model provides the advantages of parsimony and transparency, but it also imposes considerable caveats. For example, the analysis is based on a globally aggregated model and is hence silent on intragenerational distribution of costs and benefits. In addition, the analysis neglects the effects of future learning and is based on a simple representation of climate change impacts. We use this integrated assessment model to show three main points. First, substituting aerosol geoengineering for the reduction of greenhouse gas emissions can fail the test of economic efficiency. One key to this finding is that a failure to sustain the aerosol forcing can lead to sizeable and abrupt climatic changes. The monetary damages due to such a discontinuous aerosol geoengineering can dominate the cost-benefit analysis because the monetary damages of climate change are expected to increase with

  1. Assessing the nonlinear response of fine particles to precursor emissions: Development and application of an extended response surface modeling technique v1.0

    DOE PAGES

    Zhao, B.; Wang, S. X.; Xing, J.; ...

    2015-01-30

    An innovative extended response surface modeling technique (ERSM v1.0) is developed to characterize the nonlinear response of fine particles (PM₂̣₅) to large and simultaneous changes of multiple precursor emissions from multiple regions and sectors. The ERSM technique is developed based on the conventional response surface modeling (RSM) technique; it first quantifies the relationship between PM₂̣₅ concentrations and the emissions of gaseous precursors from each single region using the conventional RSM technique, and then assesses the effects of inter-regional transport of PM₂̣₅ and its gaseous precursors on PM₂̣₅ concentrations in the target region. We apply this novel technique with a widelymore » used regional chemical transport model (CTM) over the Yangtze River delta (YRD) region of China, and evaluate the response of PM₂̣₅ and its inorganic components to the emissions of 36 pollutant–region–sector combinations. The predicted PM₂̣₅ concentrations agree well with independent CTM simulations; the correlation coefficients are larger than 0.98 and 0.99, and the mean normalized errors (MNEs) are less than 1 and 2% for January and August, respectively. It is also demonstrated that the ERSM technique could reproduce fairly well the response of PM₂̣₅ to continuous changes of precursor emission levels between zero and 150%. Employing this new technique, we identify the major sources contributing to PM₂̣₅ and its inorganic components in the YRD region. The nonlinearity in the response of PM₂̣₅ to emission changes is characterized and the underlying chemical processes are illustrated.« less

  2. Assessing the nonlinear response of fine particles to precursor emissions: Development and application of an extended response surface modeling technique v1.0

    SciTech Connect

    Zhao, B.; Wang, S. X.; Xing, J.; Fu, K.; Fu, J. S.; Jang, C.; Zhu, Y.; Dong, X. Y.; Gao, Y.; Wu, W. J.; Wang, J. D.; Hao, J. M.

    2015-01-30

    An innovative extended response surface modeling technique (ERSM v1.0) is developed to characterize the nonlinear response of fine particles (PM₂̣₅) to large and simultaneous changes of multiple precursor emissions from multiple regions and sectors. The ERSM technique is developed based on the conventional response surface modeling (RSM) technique; it first quantifies the relationship between PM₂̣₅ concentrations and the emissions of gaseous precursors from each single region using the conventional RSM technique, and then assesses the effects of inter-regional transport of PM₂̣₅ and its gaseous precursors on PM₂̣₅ concentrations in the target region. We apply this novel technique with a widely used regional chemical transport model (CTM) over the Yangtze River delta (YRD) region of China, and evaluate the response of PM₂̣₅ and its inorganic components to the emissions of 36 pollutant–region–sector combinations. The predicted PM₂̣₅ concentrations agree well with independent CTM simulations; the correlation coefficients are larger than 0.98 and 0.99, and the mean normalized errors (MNEs) are less than 1 and 2% for January and August, respectively. It is also demonstrated that the ERSM technique could reproduce fairly well the response of PM₂̣₅ to continuous changes of precursor emission levels between zero and 150%. Employing this new technique, we identify the major sources contributing to PM₂̣₅ and its inorganic components in the YRD region. The nonlinearity in the response of PM₂̣₅ to emission changes is characterized and the underlying chemical processes are illustrated.

  3. Lead isotopes in trade wind aerosols at Barbados - The influence of European emissions over the North Atlantic

    NASA Technical Reports Server (NTRS)

    Hamelin, B.; Grousset, F. E.; Biscaye, P. E.; Zindler, A.; Prospero, J. M.

    1989-01-01

    Previous studies have shown that Pb can be used as a transient tracer in the atmosphere and the ocean because of strong time-variability of industrial inputs and because Pb isotopic composition can be used to identify contributions from different sources. Pb isotopic measurements on aerosols collected from the North Atlantic Ocean in the trade wind belt are presented. Aerosols sampled at Barbados during the 1969-1985 period have a Pb isotopic composition different from that observed by previous investigators in Bermuda corals and Sargasso Sea waters. Barbados aerosols appear to contain significant amounts of relatively unradiogenic industrial and automotive Pb that is derived from Europe and carried to Barbados by the trade winds. In contrast, Bermuda corals and Sargasso sea waters are influenced mainly by U.S.-derived emissions, which contain more radiogenic Pb originating from Missouri-type ores. This difference generates a strong latitudinal Europe-U.S.A. isotopic gradient, thus allowing study of trans-Atlantic atmospheric transport and ocean mixing processes.

  4. Lead isotopes in trade wind aerosols at Barbados: the influence of European emissions over the North Atlantic

    SciTech Connect

    Hamelin, B.; Grousset, F.E.; Biscaye, P.E.; Zindler, A. ); Prospero, J.M. )

    1989-11-15

    Previous studies have shown that Pb can be used as a transient tracer in the atmosphere and the ocean because of strong time-variability of industrial inputs and because Pb isotopic composition can be used to identify contribution from different sources. We present Pb isotopic measurements on aerosols collected from the North Atlantic Ocean in the trade wind belt. Aerosols sampled at Barbados during the 1969--1985 period have a Pb isotopic compositions different from that observed by previous investigators in Bermuda corals and Sargasso Sea waters. Barbados aerosols appear to contain significant amounts of relatively unradiogenic industrial and automotive Pb that is derived from Europe and carried to Barbados by the trade winds. In contrast, Bermuda corals and Sargasso sea waters are influenced mainly by U.S.-derived emissions, which contain more radiogenic Pb originating from Missouri-type ores. This difference generates a strong latitudinal Europe-U.S.A. isotopic gradient, thus allowing study of trans-Atlantic atmospheric transport and ocean mixing processes. {copyright} American Geophysical Union 1989

  5. Effect of regional precursor emission controls on long-range ozone transport - Part 2: Steady-state changes in ozone air quality and impacts on human mortality

    NASA Astrophysics Data System (ADS)

    West, J. J.; Naik, V.; Horowitz, L. W.; Fiore, A. M.

    2009-08-01

    Large-scale changes in ozone precursor emissions affect ozone directly in the short term, and also affect methane, which in turn causes long-term changes in ozone that affect surface ozone air quality. Here we assess the effects of changes in ozone precursor emissions on the long-term change in surface ozone via methane, as a function of the emission region, by modeling 10% reductions in anthropogenic nitrogen oxide (NOx) emissions from each of nine world regions. Reductions in NOx emissions from all world regions increase methane and long-term surface ozone. While this long-term increase is small compared to the intra-regional short-term ozone decrease, it is comparable to or larger than the short-term inter-continental ozone decrease for some source-receptor pairs. The increase in methane and long-term surface ozone per ton of NOx reduced is greatest in tropical and Southern Hemisphere regions, exceeding that from temperate Northern Hemisphere regions by roughly a factor of ten. We also assess changes in premature ozone-related human mortality associated with regional precursor reductions and long-range transport, showing that for 10% regional NOx reductions, the strongest inter-regional influence is for emissions from Europe affecting mortalities in Africa. Reductions of NOx in North America, Europe, the Former Soviet Union, and Australia are shown to reduce more mortalities outside of the source regions than within. Among world regions, NOx reductions in India cause the greatest number of avoided mortalities per ton, mainly in India itself. Finally, by increasing global methane, NOx reductions in one hemisphere tend to cause long-term increases in ozone concentration and mortalities in the opposite hemisphere. Reducing emissions of methane, and to a lesser extent carbon monoxide and non-methane volatile organic compounds, alongside NOx reductions would avoid this disbenefit.

  6. Effect of regional precursor emission controls on long-range ozone transport - Part 2: steady-state changes in ozone air quality and impacts on human mortality

    NASA Astrophysics Data System (ADS)

    West, J. J.; Naik, V.; Horowitz, L. W.; Fiore, A. M.

    2009-03-01

    Large-scale changes in ozone precursor emissions affect ozone directly in the short term, and also affect methane, which in turn causes long-term changes in ozone that affect surface ozone air quality. Here we assess the effects of changes in ozone precursor emissions on the long-term change in surface ozone via methane, as a function of the emission region, by modeling 10% reductions in anthropogenic nitrogen oxide (NOx) emissions from each of nine world regions. Reductions in NOx emissions from all world regions increase methane and long-term surface ozone. While this long-term increase is small compared to the intra-regional short-term ozone decrease, it is comparable to or larger than the short-term inter-continental ozone decrease for some source-receptor pairs. The increase in methane and long-term surface ozone per ton of NOx reduced is greatest in tropical and Southern Hemisphere regions, exceeding that from temperate Northern Hemisphere regions by roughly a factor of ten. We also assess changes in premature ozone-related human mortality associated with regional precursor reductions and long-range transport, showing that for 10% regional NOx reductions, the strongest inter-regional influence is for emissions from Europe affecting mortalities in Africa. Reductions of NOx in North America, Europe, the Former Soviet Union, and Australia are shown to reduce more mortalities outside of the source regions than within. Among world regions, NOx reductions in India cause the greatest number of avoided mortalities per ton, mainly in India itself. Finally, by increasing global methane, NOx reductions in one hemisphere tend to cause long-term increases in ozone concentration and mortalities in the opposite hemisphere. Reducing emissions of methane, and to a lesser extent carbon monoxide and non-methane volatile organic compounds, alongside NOx reductions would avoid this disbenefit.

  7. TOXICOLOGICAL EVALUATION OF REALISTIC EMISSIONS OF SOURCE AEROSOLS (TERESA): APPLICATION TO POWER PLANT-DERIVED PM2.5

    SciTech Connect

    Annette Rohr

    2006-03-01

    TERESA (Toxicological Evaluation of Realistic Emissions of Source Aerosols) involves exposing laboratory rats to realistic coal-fired power plant and mobile source emissions to help determine the relative toxicity of these PM sources. There are three coal-fired power plants in the TERESA program; this report describes the results of fieldwork conducted at the first plant, located in the Upper Midwest. The project was technically challenging by virtue of its novel design and requirement for the development of new techniques. By examining aged, atmospherically transformed aerosol derived from power plant stack emissions, we were able to evaluate the toxicity of PM derived from coal combustion in a manner that more accurately reflects the exposure of concern than existing methodologies. TERESA also involves assessment of actual plant emissions in a field setting--an important strength since it reduces the question of representativeness of emissions. A sampling system was developed and assembled to draw emissions from the stack; stack sampling conducted according to standard EPA protocol suggested that the sampled emissions are representative of those exiting the stack into the atmosphere. Two mobile laboratories were then outfitted for the study: (1) a chemical laboratory in which the atmospheric aging was conducted and which housed the bulk of the analytical equipment; and (2) a toxicological laboratory, which contained animal caging and the exposure apparatus. Animal exposures were carried out from May-November 2004 to a number of simulated atmospheric scenarios. Toxicological endpoints included (1) pulmonary function and breathing pattern; (2) bronchoalveolar lavage fluid cytological and biochemical analyses; (3) blood cytological analyses; (4) in vivo oxidative stress in heart and lung tissue; and (5) heart and lung histopathology. Results indicated no differences between exposed and control animals in any of the endpoints examined. Exposure concentrations for the

  8. Characterization of Chromophoric Water-Soluble Organic Matter in Urban, Forest, and Marine Aerosols by HR-ToF-AMS Analysis and Excitation-Emission Matrix Spectroscopy.

    PubMed

    Chen, Qingcai; Miyazaki, Yuzo; Kawamura, Kimitaka; Matsumoto, Kiyoshi; Coburn, Sean; Volkamer, Rainer; Iwamoto, Yoko; Kagami, Sara; Deng, Yange; Ogawa, Shuhei; Ramasamy, Sathiyamurthi; Kato, Shungo; Ida, Akira; Kajii, Yoshizumi; Mochida, Michihiro

    2016-10-04

    Chromophoric water-soluble organic matter in atmospheric aerosols potentially plays an important role in aqueous reactions and light absorption by organics. The fluorescence and chemical-structural characteristics of the chromophoric water-soluble organic matter in submicron aerosols collected in urban, forest, and marine environments (Nagoya, Kii Peninsula, and the tropical Eastern Pacific) were investigated using excitation-emission matrices (EEMs) and a high-resolution aerosol mass spectrometer. A total of three types of water-soluble chromophores, two with fluorescence characteristics similar to those of humiclike substances (HULIS-1 and HULIS-2) and one with fluorescence characteristics similar to those of protein compounds (PLOM), were identified in atmospheric aerosols by parallel factor analysis (PARAFAC) for EEMs. We found that the chromophore components of HULIS-1 and -2 were associated with highly and less-oxygenated structures, respectively, which may provide a clue to understanding the chemical formation or loss of organic chromophores in atmospheric aerosols. Whereas HULIS-1 was ubiquitous in water-soluble chromophores over different environments, HULIS-2 was abundant only in terrestrial aerosols, and PLOM was abundant in marine aerosols. These findings are useful for further studies regarding the classification and source identification of chromophores in atmospheric aerosols.

  9. Effectiveness of sulfur and boron isotopes in aerosols as tracers of emissions from coal burning in Asian continent

    NASA Astrophysics Data System (ADS)

    Sakata, Masahiro; Ishikawa, Tomomi; Mitsunobu, Satoshi

    2013-03-01

    The atmospheric concentrations and isotopic compositions of sulfur and boron were measured for aerosol samples (water soluble fraction) collected from April 2004 to March 2006 at two sites on the Japan Sea coast. SO42- originating from sea salts in the aerosols was negligible (only 1-2% of the total SO42-). The atmospheric concentrations of nonsea-salt SO42- (Snss) and total B (BT) were scattered widely, but the concentration ratio BT/Snss was relatively high during winter and relatively low during summer. Moreover, aerosols during winter were characterized by a high δ34S (δ34Snss) of nonsea-salt SO42- and a low δ11B (δ11BT) of total B, whereas aerosols during summer were characterized by a low δ34Snss and a high δ11BT. A negative correlation (r2 = 0.34, p < 0.001) was observed between δ34Snss and δ11BT in aerosols from the two sites, suggesting that those values are governed primarily by a mixing of two end-members. On the basis of air trajectory analysis, the first end-member is the air mass from "Northern China (>30°N)", whereas the second end-member is the air mass from "Japan and the Pacific Ocean". It is likely that SO42- and B in the air mass from northern China are strongly affected by coal burning, which satisfactorily reflects the characteristics of δ34S and δ11B (i.e., high δ34S and low δ11B) of coals formed in this region. Thus, both sulfur and boron isotopes in aerosols are effective as tracers of emissions from coal burning in northern China mainly during winter when the air mass from this region is dominant. On the other hand, the results of source identification suggested that the major sources of SO42- and B in the air mass from Japan and the Pacific Ocean are oil combustion in Japan and ocean sea salts, respectively.

  10. The Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1): an extended and updated framework for modeling biogenic emissions

    NASA Astrophysics Data System (ADS)

    Guenther, A. B.; Jiang, X.; Heald, C. L.; Sakulyanontvittaya, T.; Duhl, T.; Emmons, L. K.; Wang, X.

    2012-06-01

    The Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1) is a modeling framework for estimating fluxes of 147 biogenic compounds between terrestrial ecosystems and the atmosphere using simple mechanistic algorithms to account for the major known processes controlling biogenic emissions. It is available as an offline code and has also been coupled into land surface models and atmospheric chemistry models. MEGAN2.1 is an update from the previous versions including MEGAN2.0 for isoprene emissions and MEGAN2.04, which estimates emissions of 138 compounds. Isoprene comprises about half of the estimated total global biogenic volatile organic compound (BVOC) emission of 1 Pg (1000 Tg or 1015 g). Another 10 compounds including methanol, ethanol, acetaldehyde, acetone, α-pinene, β-pinene, t-β-ocimene, limonene, ethene, and propene together contribute another 30% of the estimated emission. An additional 20 compounds (mostly terpenoids) are associated with another 17% of the total emission with the remaining 3% distributed among 125 compounds. Emissions of 41 monoterpenes and 32 sesquiterpenes together comprise about 15% and 3%, respectively, of the total global BVOC emission. Tropical trees cover about 18% of the global land surface and are estimated to be responsible for 60% of terpenoid emissions and 48% of other VOC emissions. Other trees cover about the same area but are estimated to contribute only about 10% of total emissions. The magnitude of the emissions estimated with MEGAN2.1 are within the range of estimates reported using other approaches and much of the differences between reported values can be attributed to landcover and meteorological driving variables. The offline version of MEGAN2.1 source code and driving variables is available from http://acd.ucar.edu/~guenther/MEGAN/MEGAN.htm and the version integrated into the Community Land Model version 4 (CLM4) can

  11. The Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1): an extended and updated framework for modeling biogenic emissions

    NASA Astrophysics Data System (ADS)

    Guenther, A. B.; Jiang, X.; Heald, C. L.; Sakulyanontvittaya, T.; Duhl, T.; Emmons, L. K.; Wang, X.

    2012-11-01

    The Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1) is a modeling framework for estimating fluxes of biogenic compounds between terrestrial ecosystems and the atmosphere using simple mechanistic algorithms to account for the major known processes controlling biogenic emissions. It is available as an offline code and has also been coupled into land surface and atmospheric chemistry models. MEGAN2.1 is an update from the previous versions including MEGAN2.0, which was described for isoprene emissions by Guenther et al. (2006) and MEGAN2.02, which was described for monoterpene and sesquiterpene emissions by Sakulyanontvittaya et al. (2008). Isoprene comprises about half of the total global biogenic volatile organic compound (BVOC) emission of 1 Pg (1000 Tg or 1015 g) estimated using MEGAN2.1. Methanol, ethanol, acetaldehyde, acetone, α-pinene, β-pinene, t-β-ocimene, limonene, ethene, and propene together contribute another 30% of the MEGAN2.1 estimated emission. An additional 20 compounds (mostly terpenoids) are associated with the MEGAN2.1 estimates of another 17% of the total emission with the remaining 3% distributed among >100 compounds. Emissions of 41 monoterpenes and 32 sesquiterpenes together comprise about 15% and 3%, respectively, of the estimated total global BVOC emission. Tropical trees cover about 18% of the global land surface and are estimated to be responsible for ~80% of terpenoid emissions and ~50% of other VOC emissions. Other trees cover about the same area but are estimated to contribute only about 10% of total emissions. The magnitude of the emissions estimated with MEGAN2.1 are within the range of estimates reported using other approaches and much of the differences between reported values can be attributed to land cover and meteorological driving variables. The offline version of MEGAN2.1 source code and driving variables is available from

  12. Optical Properties and Mixing State of Aerosols from Residential Wood Burning and Vehicle Emissions in Central and Southern California

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Cappa, C. D.; Collier, S.; Zhang, Q.; Williams, L. R.; Lee, A.; Abbatt, J.; Russell, L. M.; Liu, J.; Chen, C. L.; Betha, R.

    2015-12-01

    Light-absorbing materials such as black carbon (BC) and brown carbon (BrC) in atmospheric aerosols play important roles in regulating the earth's radiative budget and climate. However, the representations of BC and BrC in state-of-the-art climate models remain highly uncertain, in part due to the poor understanding of their microphysical and optical properties. Direct observations and characterizations of the mixing state and absorption enhancement of ambient aerosols could provide invaluable constraints for current model representations of aerosol radiative effects. Here, we will discuss results from measurements of aerosol light absorption and absorption enhancement (Eabs), using a thermodenuder-absorption method, made during two recent field studies in central and southern California. The winter study took place in Dec/Jan of 2014/2015 in Fresno, CA. This region is severely impacted by particulate matter from local and regional residential biomass burning. The summer study took place in July 2015 in Fontana, CA, a region ~80 km downwind of Los Angeles and strongly impacted by vehicular emissions, and thus provides a sharp contrast to the Fresno study. Eabs of BC particles due to the "lensing" effect from coatings to BC core and/or the presence of BrC will be quantified and compared between the two studies. Additionally, the chemical composition of bulk and the BC-containing particles are determined via a HR-ToF-AMS and a SP-AMS, respectively. Variations in the composition and mixing state of the ambient particles and how these affect the observed Eabs will be examined. The overall measurements suggest a relatively small role for lensing-induced absorption enhancements for ambient particles in these regions.

  13. Impact of future climate policy scenarios on air quality and aerosol-cloud interactions using an advanced version of CESM/CAM5: Part II. Future trend analysis and impacts of projected anthropogenic emissions

    NASA Astrophysics Data System (ADS)

    Glotfelty, Timothy; Zhang, Yang

    2017-03-01

    Following a comprehensive evaluation of the Community Earth System Model modified at the North Carolina State University (CESM-NCSU), Part II describes the projected changes in the future state of the atmosphere under the representative concentration partway scenarios (RCP4.5 and 8.5) by 2100 for the 2050 time frame and examine the impact of climate change on future air quality under both scenarios, and the impact of projected emission changes under the RCP4.5 scenario on future climate through aerosol direct and indirect effects. Both the RCP4.5 and RCP8.5 simulations predict similar changes in air quality by the 2050 period due to declining emissions under both scenarios. The largest differences occur in O3, which decreases by global mean of 1.4 ppb under RCP4.5 but increases by global mean of 2.3 ppb under RCP8.5 due to differences in methane levels, and PM10, which decreases by global mean of 1.2 μg m-3 under RCP4.5 and increases by global mean of 0.2 μg m-3 under RCP8.5 due to differences in dust and sea-salt emissions under both scenarios. Enhancements in cloud formation in the Arctic and Southern Ocean and increases of aerosol optical depth (AOD) in central Africa and South Asia dominate the change in surface radiation in both scenarios, leading to global average dimming of 1.1 W m-2 and 2.0 W m-2 in the RCP4.5 and RCP8.5 scenarios, respectively. Declines in AOD, cloud formation, and cloud optical thickness from reductions of emissions of primary aerosols and aerosol precursors under RCP4.5 result in near surface warming of 0.2 °C from a global average increase of 0.7 W m-2 in surface downwelling solar radiation. This warming leads to a weakening of the Walker Circulation in the tropics, leading to significant changes in cloud and precipitation that mirror a shift in climate towards the negative phase of the El Nino Southern Oscillation.

  14. Spatial variations in immediate greenhouse gases and aerosol emissions and resulting radiative forcing from wildfires in interior Alaska

    USGS Publications Warehouse

    Huang, Shengli; Liu, Heping; Dahal, Devendra; Jin, Suming; Li, Shuang; Liu, Shu-Guang

    2016-01-01

    Boreal fires can cool the climate; however, this conclusion came from individual fires and may not represent the whole story. We hypothesize that the climatic impact of boreal fires depends on local landscape heterogeneity such as burn severity, prefire vegetation type, and soil properties. To test this hypothesis, spatially explicit emission of greenhouse gases (GHGs) and aerosols and their resulting radiative forcing are required as an important and necessary component towards a full assessment. In this study, we integrated remote sensing (Landsat and MODIS) and models (carbon consumption model, emission factors model, and radiative forcing model) to calculate the carbon consumption, GHGs and aerosol emissions, and their radiative forcing of 2001–2010 fires at 30 m resolution in the Yukon River Basin of Alaska. Total carbon consumption showed significant spatial variation, with a mean of 2,615 g C m−2 and a standard deviation of 2,589 g C m−2. The carbon consumption led to different amounts of GHGs and aerosol emissions, ranging from 593.26 Tg (CO2) to 0.16 Tg (N2O). When converted to equivalent CO2 based on global warming potential metric, the maximum 20 years equivalent CO2 was black carbon (713.77 Tg), and the lowest 20 years equivalent CO2 was organic carbon (−583.13 Tg). The resulting radiative forcing also showed significant spatial variation: CO2, CH4, and N2O can cause a 20-year mean radiative forcing of 7.41 W m−2 with a standard deviation of 2.87 W m−2. This emission forcing heterogeneity indicates that different boreal fires have different climatic impacts. When considering the spatial variation of other forcings, such as surface shortwave forcing, we may conclude that some boreal fires, especially boreal deciduous fires, can warm the climate.

  15. Impact of the March 2009 dust event in Saudi Arabia on aerosol optical properties, meteorological parameters, sky temperature and emissivity

    NASA Astrophysics Data System (ADS)

    Maghrabi, A.; Alharbi, B.; Tapper, N.

    2011-04-01

    On 10th March 2009 a widespread and severe dust storm event that lasted several hours struck Riyadh, and represented one of the most intense dust storms experienced in Saudi Arabia in the last two decades. This short-lived storm caused widespread and heavy dust deposition, zero visibility and total airport shutdown, as well as extensive damage to buildings, vehicles, power poles and trees across the city of Riyadh. Changes in Meteorological parameters, aerosol optical depth (AOD), Angstrom exponent α, infrared (IR) sky temperature and atmospheric emissivity were investigated before, during, and after the storm. The analysis showed significant changes in all of the above parameters due to this event. Shortly after the storm arrived, air pressure rapidly increased by 4 hPa, temperature decreased by 6 °C, relative humidly increased from 10% to 30%, the wind direction became northerly and the wind speed increased to a maximum of 30 m s -1. AOD at 550 nm increased from 0.396 to 1.71. The Angstrom exponent α rapidly decreased from 0.192 to -0.078. The mean AOD at 550 nm on the day of the storm was 0.953 higher than during the previous clear day, while α was -0.049 in comparison with 0.323 during the previous day. Theoretical simulations using SMART software showed remarkable changes in both spectral and broadband solar radiation components. The global and direct radiation components decreased by 42% and 68%, respectively, and the diffuse components increased by 44% in comparison with the previous clear day. IR sky temperatures and sky emissivity increased by 24 °C and 0.3, respectively, 2 h after the arrival of the storm. The effect of aerosol loading by the storm on IR atmospheric emission was investigated using MODTRAN software. It was found that the effect of aerosols caused an increase of the atmospheric emission in the atmospheric window (8-14 μm) such that the window emissions resembled those of a blackbody and the atmospheric window was almost closed.

  16. TOXICOLOGICAL EVALUATION OF REALISTIC EMISSIONS OF SOURCE AEROSOLS (TERESA): APPLICATION TO POWER PLANT-DERIVED PM2.5

    SciTech Connect

    Annette Rohr

    2005-03-31

    This report documents progress made on the subject project during the period of September 1, 2004 through February 28, 2005. The TERESA Study is designed to investigate the role played by specific emissions sources and components in the induction of adverse health effects by examining the relative toxicity of coal combustion and mobile source (gasoline and/or diesel engine) emissions and their oxidative products. The study involves on-site sampling, dilution, and aging of coal combustion emissions at three coal-fired power plants, as well as mobile source emissions, followed by animal exposures incorporating a number of toxicological endpoints. The DOE-EPRI Cooperative Agreement (henceforth referred to as ''the Agreement'') for which this technical progress report has been prepared covers the performance and analysis of field experiments at the first TERESA plant, located in the Upper Midwest and henceforth referred to as Plant 0, and at two additional coal-fired power plants (Plants 1 and 2) utilizing different coal types and with different plant configurations. During this reporting period, all fieldwork at Plant 0 was completed. Stack sampling was conducted in October to determine if there were significant differences between the in-stack PM concentrations and the diluted concentrations used for the animal exposures. Results indicated no significant differences and therefore confidence that the revised stack sampling methodology described in the previous semiannual report is appropriate for use in the Project. Animal exposures to three atmospheric scenarios were carried out. From October 4-7, we conducted exposures to oxidized emissions with the addition of secondary organic aerosol (SOA). Later in October, exposures to the most complex scenario (oxidized, neutralized emissions plus SOA) were repeated to ensure comparability with the results of the June/July exposures where a different stack sampling setup was employed. In November, exposures to oxidized

  17. Dimethyl Sulfide Emissions from Dairies and Agriculture as a Potential Contributor to Sulfate Aerosols in the California Central Valley

    NASA Astrophysics Data System (ADS)

    Lebel, E.; Marrero, J. E.; Bertram, T. H.; Blake, D. R.

    2014-12-01

    Whole air samples have been collected throughout Southern California during the previous five years of the NASA Student Airborne Research Program (SARP). During a flight over the Salton Sea in 2014, higher concentrations of dimethyl sulfide (DMS), a known marine emitted gas, were observed over neighboring agricultural land than over the sea itself. A comparison of DMS to methyl iodide, another known marine emitted gas, showed minimal correlation, revealing that DMS was being emitted from local sources. Ground samples at the Salton Sea verified that the DMS was not transported from the Pacific Ocean. Previous SARP studies have shown that DMS is emitted from dairies. The enhancements in ethanol (another dairy tracer) and DMS in several airborne samples collected south of the Salton Sea suggest dairy emissions of the observed DMS. DMS is a compound of interest because its oxidation can form cloud condensation nuclei. Based on data from all six SARP flights between 2009-2014, we propose that dairy and farming emissions of DMS in the San Joaquin Valley may be impacting aerosol loading in this region. A simple model that takes into account the particulate matter mass loadings was used to calculate the percent contribution of DMS to aerosol formation for the San Joaquin Valley.

  18. The use of satellite-measured aerosol optical depth to constrain biomass burning emissions source strength in the global model GOCART

    NASA Astrophysics Data System (ADS)

    Petrenko, Mariya; Kahn, Ralph; Chin, Mian; Soja, Amber; Kucsera, Tom; Harshvardhan, null

    2012-09-01

    Simulations of biomass burning (BB) emissions in chemistry transport models strongly depend on the inventories that define emission source location and strength. We use 13 global biomass burning emission estimates, including the widely used Global Fire Emission Database (GFED) monthly and daily versions, Fire Radiative Power (FRP)-based Quick Fire Emission Data set QFED, and 11 calculated emissions from different combinations of burned area based on the Moderate Resolution Imaging Spectroradiometer (MODIS) products, effective fuel load, and species emission factors as alternative inputs to the global Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. The resultant simulated aerosol optical depth (AOD) and its spatial distribution are compared to AOD snapshots measured by the MODIS instrument for 124 fire events occurring between 2006 and 2007. This comparison exposes the regional biases of each emission option. GOCART average fire AOD values compare best to MODIS-measured AOD when the daily GFED inventory is used as input to GOCART. Even though GFED-based emission options provide the lowest emissions in the tropics, GFED-based GOCART AOD compares best with MODIS AOD in tropical cases. Fire-counts-based emission options give the largest emission estimates in the boreal regions, and the model performs best at higher latitudes with these inputs when compared to MODIS. Comparison of total annual BB emissions by all inventories suggests that burned area estimates are usually the largest source of disagreement. It is also shown that the quantitative relationship between BB aerosol emission rate and model-simulated AOD is related to the horizontal plume dispersion, which can be approximated by the wind speed in the planetary boundary layer in most cases. Thus, given average wind speed of the smoke plume environment, MODIS-measured AOD can provide a constraint to the strength of BB sources at the level of individual plumes.

  19. Multi-Decadal Variation of Aerosols: Sources, Transport, and Climate Effects

    NASA Technical Reports Server (NTRS)

    Chin, Mian; Diehl, Thomas; Bian, Huisheng; Streets, David

    2008-01-01

    We present a global model study of multi-decadal changes of atmospheric aerosols and their climate effects using a global chemistry transport model along with the near-term to longterm data records. We focus on a 27-year time period of satellite era from 1980 to 2006, during which a suite of aerosol data from satellite observations, ground-based measurements, and intensive field experiments have become available. We will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, which involves a time-varying, comprehensive global emission dataset that we put together in our previous investigations and will be improved/extended in this project. This global emission dataset includes emissions of aerosols and their precursors from fuel combustion, biomass burning, volcanic eruptions, and other sources from 1980 to the present. Using the model and satellite data, we will analyze (1) the long-term global and regional aerosol trends and their relationship to the changes of aerosol and precursor emissions from anthropogenic and natural sources, (2) the intercontinental source-receptor relationships controlled by emission, transport pathway, and climate variability.

  20. Light Absorption Properties and Radiative Effects of Primary Organic Aerosol Emissions

    EPA Science Inventory

    Organic aerosols (OA) in the atmosphere affect Earth’s energy budget by not only scattering but also absorbing solar radiation due to the presence of the so-called “brown carbon” (BrC) component. However, the absorptivities of OA are not or poorly represented in current climate m...

  1. The effect of marine isoprene emissions on secondary organic aerosol and ozone formation in the coastal United States

    NASA Astrophysics Data System (ADS)

    Gantt, Brett; Meskhidze, Nicholas; Zhang, Yang; Xu, Jun

    2010-01-01

    The impact of marine isoprene emissions on summertime surface concentrations of isoprene, secondary organic aerosols (SOA), and ozone (O 3) in the coastal areas of the continental United States is studied using the U.S. Environmental Protection Agency regional-scale Community Multiscale Air Quality (CMAQ) modeling system. Marine isoprene emission rates are based on the following five parameters: laboratory measurements of isoprene production from phytoplankton under a range of light conditions, remotely-sensed chlorophyll- a concentration ([Chl- a]), incoming solar radiation, surface wind speed, and sea-water optical properties. Model simulations show that marine isoprene emissions are sensitive to meteorology and ocean ecosystem productivity, with the highest rates simulated over the Gulf of Mexico. Simulated offshore surface layer marine isoprene concentration is less than 10 ppt and significantly dwarfed by terrestrial emissions over the continental United States. With the isoprene reactions included in this study, the average contribution of marine isoprene to SOA and O 3 concentrations is predicted to be small, up to 0.004 μg m -3 for SOA and 0.2 ppb for O 3 in coastal urban areas. The light-sensitivity of isoprene production from phytoplankton results in a midday maximum for marine isoprene emissions and a corresponding daytime increase in isoprene and O 3 concentrations in coastal locations. The potential impact of the daily variability in [Chl- a] on O 3 and SOA concentrations is simulated in a sensitivity study with [Chl- a] increased and decreased by a factor of five. Our results indicate that marine emissions of isoprene cause minor changes to coastal SOA and O 3 concentrations. Comparison of model simulations with few available measurements shows that the model underestimates marine boundary layer isoprene concentration. This underestimation is likely due to the limitations in current treatment of marine isoprene emission and a coarse spatial

  2. Primary to secondary organic aerosol: evolution of organic emissions from mobile combustion sources

    NASA Astrophysics Data System (ADS)

    Presto, A. A.; Gordon, T. D.; Robinson, A. L.

    2014-05-01

    A series of smog chamber experiments were conducted to investigate the transformation of primary organic aerosol (POA) and formation of secondary organic aerosol (SOA) during the photooxidation of dilute exhaust from a fleet of gasoline and diesel motor vehicles and two gas-turbine engines. In experiments where POA was present in the chamber at the onset of photooxidation, positive matrix factorization (PMF) was used to determine separate POA and SOA factors from aerosol mass spectrometer data. A 2-factor solution, with one POA factor and one SOA factor, was sufficient to describe the organic aerosol for gasoline vehicles, diesel vehicles, and one of the gas-turbine engines. Experiments with the second gas-turbine engine required a 3-factor PMF solution with a POA factor and two SOA factors. Results from the PMF analysis were compared to the residual method for determining SOA and POA mass concentrations. The residual method apportioned a larger fraction of the organic aerosol mass as POA because it assumes that all mass at m / z 57 is associated with POA. The POA mass spectrum for the gasoline and diesel vehicles exhibited high abundances of the CnH2n+1 series of ions (m / z 43, 57, etc.) and was similar to the mass spectra of the hydrocarbon-like organic aerosol factor determined from ambient data sets with one exception, a diesel vehicle equipped with a diesel oxidation catalyst. POA mass spectra for the gas-turbine engines are enriched in the CnH2n-1 series of ions (m / z 41, 55, etc.), consistent with the composition of the lubricating oil used in these engines. The SOA formed from the three sources exhibits high abundances of m / z 44 and 43, indicative of mild oxidation. The SOA mass spectra are consistent with less-oxidized ambient SV-OOA (semivolatile oxygenated organic aerosols) and fall within the triangular region of f44 versus f43 defined by ambient measurements. However there is poor absolute agreement between the experimentally derived SOA mass

  3. Radiative forcing and climate response to projected 21st century aerosol decreases

    NASA Astrophysics Data System (ADS)

    Westervelt, D. M.; Horowitz, L. W.; Naik, V.; Golaz, J.-C.; Mauzerall, D. L.

    2015-11-01

    It is widely expected that global emissions of atmospheric aerosols and their precursors will decrease strongly throughout the remainder of the 21st century, due to emission reduction policies enacted to protect human health. For instance, global emissions of aerosols and their precursors are projected to decrease by as much as 80 % by the year 2100, according to the four Representative Concentration Pathway (RCP) scenarios. The removal of aerosols will cause unintended climate consequences, including an unmasking of global warming from long-lived greenhouse gases. We use the Geophysical Fluid Dynamics Laboratory Coupled Climate Model version 3 (GFDL CM3) to simulate future climate over the 21st century with and without the aerosol emission changes projected by each of the RCPs in order to isolate the radiative forcing and climate response resulting from the aerosol reductions. We find that the projected global radiative forcing and climate response due to aerosol decreases do not vary significantly across the four RCPs by 2100, although there is some mid-century variation, especially in cloud droplet effective radius, that closely follows the RCP emissions and energy consumption projections. Up to 1 W m-2 of radiative forcing may be unmasked globally from 2005 to 2100 due to reductions in aerosol and precursor emissions, leading to average global temperature increases up to 1 K and global precipitation rate increases up to 0.09 mm day-1. However, when using a version of CM3 with reduced present-day aerosol radiative forcing (-1.0 W m-2), the global temperature increase for RCP8.5 is about 0.5 K, with similar magnitude decreases in other climate response parameters as well. Regionally and locally, climate impacts can be much larger than the global mean, with a 2.1 K warming projected over China, Japan, and Korea due to the reduced aerosol emissions in RCP8.5, as well as nearly a 0.2 mm day-1 precipitation increase, a 7 g m-2 LWP decrease, and a 2 μm increase in

  4. Characterization of emissions from South Asian biofuels and application to source apportionment of carbonaceous aerosol in the Himalayas

    NASA Astrophysics Data System (ADS)

    Stone, Elizabeth A.; Schauer, James J.; Pradhan, Bidya Banmali; Dangol, Pradeep Man; Habib, Gazala; Venkataraman, Chandra; Ramanathan, V.

    2010-03-01

    This study focuses on improving source apportionment of carbonaceous aerosol in South Asia and consists of three parts: (1) development of novel molecular marker-based profiles for real-world biofuel combustion, (2) application of these profiles to a year-long data set, and (3) evaluation of profiles by an in-depth sensitivity analysis. Emissions profiles for biomass fuels were developed through source testing of a residential stove commonly used in South Asia. Wood fuels were combusted at high and low rates, which corresponded to source profiles high in organic carbon (OC) or high in elemental carbon (EC), respectively. Crop wastes common to the region, including rice straw, mustard stalk, jute stalk, soybean stalk, and animal residue burnings, were also characterized. Biofuel profiles were used in a source apportionment study of OC and EC in Godavari, Nepal. This site is located in the foothills of the Himalayas and was selected for its well-mixed and regionally impacted air masses. At Godavari, daily samples of fine particulate matter (PM2.5) were collected throughout the year of 2006, and the annual trends in particulate mass, OC, and EC followed the occurrence of a regional haze in South Asia. Maximum concentrations occurred during the dry winter season and minimum concentrations occurred during the summer monsoon season. Specific organic compounds unique to aerosol sources, molecular markers, were measured in monthly composite samples. These markers implicated motor vehicles, coal combustion, biomass burning, cow dung burning, vegetative detritus, and secondary organic aerosol as sources of carbonaceous aerosol. A molecular marker-based chemical mass balance (CMB) model provided a quantitative assessment of primary source contributions to carbonaceous aerosol. The new profiles were compared to widely used biomass burning profiles from the literature in a sensitivity analysis. This analysis indicated a high degree of stability in estimates of source

  5. Air pollution from gas flaring: new emission factor estimates and detection in a West African aerosol remote-sensing climatology

    NASA Astrophysics Data System (ADS)

    MacKenzie, Rob; Fawole, Olusegun Gabriel; Levine, James; Cai, Xiaoming

    2016-04-01

    Gas flaring, the disposal of gas through stacks in an open-air flame, is a common feature in the processing of crude oil, especially in oil-rich regions of the world. Gas flaring is a prominent source of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAH), CO, CO2, nitrogen oxides (NOx), SO2 (in "sour" gas only), and soot (black carbon), as well as the release of locally significant amounts of heat. The rates of emission of these pollutants from gas flaring depend on a number of factors including, but not limited to, fuel composition and quantity, stack geometry, flame/combustion characteristics, and prevailing meteorological conditions. Here, we derive new estimated emission factors (EFs) for carbon-containing pollutants (excluding PAH). The air pollution dispersion model, ADMS5, is used to simulate the dispersion of the pollutants from flaring stacks in the Niger delta. A seasonal variation of the dispersion pattern of the pollutant within a year is studied in relation to the movements of the West Africa Monsoon (WAM) and other prevailing meteorological factors. Further, we have clustered AERONET aerosol signals using trajectory analysis to identify dominant aerosol sources at the Ilorin site in West Africa (4.34 oE, 8.32 oN). A 10-year trajectory-based analysis was undertaken (2005-2015, excluding 2010). Of particular interest are air masses that have passed through the gas flaring region in the Niger Delta area en-route the AERONET site. 7-day back trajectories were calculated using the UK Universities Global Atmospheric Modelling Programme (UGAMP) trajectory model which is driven by analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF). From the back-trajectory calculations, dominant sources are identified, using literature classifications: desert dust (DD); Biomass burning (BB); and Urban-Industrial (UI). We use a combination of synoptic trajectories and aerosol optical properties to distinguish a fourth source

  6. Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry.

    PubMed

    Malmborg, V B; Eriksson, A C; Shen, M; Nilsson, P; Gallo, Y; Waldheim, B; Martinsson, J; Andersson, Ö; Pagels, J

    2017-02-07

    To design diesel engines with low environmental impact, it is important to link health and climate-relevant soot (black carbon) emission characteristics to specific combustion conditions. The in-cylinder evolution of soot properties over the combustion cycle and as a function of exhaust gas recirculation (EGR) was investigated in a modern heavy-duty diesel engine. A novel combination of a fast gas-sampling valve and a soot particle aerosol mass spectrometer (SP-AMS) enabled online measurements of the in-cylinder soot chemistry. The results show that EGR reduced the soot formation rate. However, the late cycle soot oxidation rate (soot removal) was reduced even more, and the net effect was increased soot emissions. EGR resulted in an accumulation of polycyclic aromatic hydrocarbons (PAHs) during combustion, and led to increased PAH emissions. We show that mass spectral and optical signatures of the in-cylinder soot and associated low volatility organics change dramatically from the soot formation dominated phase to the soot oxidation dominated phase. These signatures include a class of fullerene carbon clusters that we hypothesize represent less graphitized, C5-containing fullerenic (high tortuosity or curved) soot nanostructures arising from decreased combustion temperatures and increased premixing of air and fuel with EGR. Altered soot properties are of key importance when designing emission control strategies such as diesel particulate filters and when introducing novel biofuels.

  7. Aerosol-computational fluid dynamics modeling of ultrafine and black carbon particle emission, dilution, and growth near roadways

    NASA Astrophysics Data S