Science.gov

Sample records for aerosol mass concentrations

  1. Workplace aerosol mass concentration measurement using optical particle counters.

    PubMed

    Görner, Peter; Simon, Xavier; Bémer, Denis; Lidén, Göran

    2012-02-01

    Direct-reading aerosol measurement usually uses the optical properties of airborne particles to detect and measure particle concentration. In the case of occupational hygiene, mass concentration measurement is often required. Two aerosol monitoring methods are based on the principle of light scattering: optical particle counting (OPC) and photometry. The former analyses the light scattered by a single particle, the latter by a cloud of particles. Both methods need calibration to transform the quantity of scattered light detected into particle concentration. Photometers are simpler to use and can be directly calibrated to measure mass concentration. However, their response varies not only with aerosol concentration but also with particle size distribution, which frequently contributes to biased measurement. Optical particle counters directly measure the particle number concentration and particle size that allows assessment of the particle mass provided the particles are spherical and of known density. An integrating algorithm is used to calculate the mass concentration of any conventional health-related aerosol fraction. The concentrations calculated thus have been compared with simultaneous measurements by conventional gravimetric sampling to check the possibility of field OPC calibration with real workplace aerosols with a view to further monitoring particle mass concentration. Aerosol concentrations were measured in the food industry using the OPC GRIMM® 1.108 and the CIP 10-Inhalable and CIP 10-Respirable (ARELCO®) aerosol samplers while meat sausages were being brushed and coated with calcium carbonate. Previously, the original OPC inlet had been adapted to sample inhalable aerosol. A mixed aerosol of calcium carbonate and fungi spores was present in the workplace. The OPC particle-size distribution and an estimated average particle density of both aerosol components were used to calculate the mass concentration. The inhalable and respirable aerosol fractions

  2. Development of a continuous aerosol mass concentration measurement device.

    PubMed

    Bémer, D; Thomas, D; Contal, P; Subra, I

    2003-08-01

    A dynamic aerosol mass concentration measurement device has been developed for personal sampling. Its principle consists in sampling the aerosol on a filter and monitoring the change of pressure drop over time (Delta P). Ensuring that the linearity of the Delta P = f(mass of particles per unit area of filter) relationship has been well established, the change of concentration can be deduced. The response of the system was validated in the laboratory with a 3.5 microm alumina aerosol (mass median diameter) generated inside a 1-m(3) ventilated enclosure. As the theory predicted that the mass sensitivity of the system would vary inversely with the square of the particle diameter, only sufficiently fine aerosols were able to be measured. The system was tested in the field in a mechanical workshop in the vicinity of an arc-welding station. The aerosol produced by welding is indeed particularly well-adapted due to the sub-micronic size of the particles. The device developed, despite this limitation, has numerous advantages over other techniques: robustness, compactness, reliability of calibration, and ease of use.

  3. Direct gravimetric determination of aerosol mass concentration in central antarctica.

    PubMed

    Annibaldi, Anna; Truzzi, Cristina; Illuminati, Silvia; Scarponi, Giuseppe

    2011-01-01

    In Antarctica, experimental difficulties due to extreme conditions have meant that aerosol mass has rarely been measured directly by gravimetry, and only in coastal areas where concentrations were in the range of 1-7 μg m(-3). The present work reports on a careful differential weighing methodology carried out for the first time on the plateau of central Antarctica (Dome C, East Antarctica). To solve problems of accurate aerosol mass measurements, a climatic room was used for conditioning and weighing filters. Measurements were carried out in long stages of several hours of readings with automatic recording of temperature/humidity and mass. This experimental scheme allowed us to sample from all the measurements (up to 2000) carried out before and after exposure, those which were recorded under the most stable humidity conditions and, even more importantly, as close to each other as possible. The automatic reading of the mass allowed us in any case to obtain hundreds of measurements from which to calculate average values with uncertainties sufficiently low to meet the requirements of the differential weighing procedure (±0.2 mg in filter weighing, between ±7% and ±16% both in aerosol mass and concentration measurements). The results show that the average summer aerosol mass concentration (aerodynamic size ≤10 μm) in central Antarctica is about 0.1 μg m(-3), i.e., about 1/10 of that of coastal Antarctic areas. The concentration increases by about 4-5 times at a site very close to the station.

  4. ModelE2-TOMAS development and evaluation using aerosol optical depths, mass and number concentrations

    NASA Astrophysics Data System (ADS)

    Lee, Y. H.; Adams, P. J.; Shindell, D. T.

    2014-09-01

    The TwO-Moment Aerosol Sectional microphysics model (TOMAS) has been integrated into the state-of-the-art general circulation model, GISS ModelE2. TOMAS has the flexibility to select a size resolution as well as the lower size cutoff. A computationally efficient version of TOMAS is used here, which has 15 size bins covering 3 nm to 10 μm aerosol dry diameter. For each bin, it simulates the total aerosol number concentration and mass concentrations of sulphate, pure elementary carbon (hydrophobic), mixed elemental carbon (hydrophilic), hydrophobic organic matter, hydrophilic organic matter, sea salt, mineral dust, ammonium, and aerosol-associated water. This paper provides a detailed description of the ModelE2-TOMAS model and evaluates the model against various observations including aerosol precursor gas concentrations, aerosol mass and number concentrations, and aerosol optical depths. Additionally, global budgets in ModelE2-TOMAS are compared with those of other global aerosol models, and the TOMAS model is compared to the default aerosol model in ModelE2, which is a bulk aerosol model. Overall, the ModelE2-TOMAS predictions are within the range of other global aerosol model predictions, and the model has a reasonable agreement with observations of sulphur species and other aerosol components as well as aerosol optical depth. However, ModelE2-TOMAS (as well as the bulk aerosol model) cannot capture the observed vertical distribution of sulphur dioxide over the Pacific Ocean possibly due to overly strong convective transport. The TOMAS model successfully captures observed aerosol number concentrations and cloud condensation nuclei concentrations. Anthropogenic aerosol burdens in the bulk aerosol model running in the same host model as TOMAS (ModelE2) differ by a few percent to a factor of 2 regionally, mainly due to differences in aerosol processes including deposition, cloud processing, and emission parameterizations. Larger differences are found for naturally

  5. A CLOSURE STUDY OF AEROSOL MASS CONCENTRATION MEASUREMENTS: COMPARISON OF VALUES OBTAINED WITH FILTERS AND BY DIRECT MEASUREMENTS OF MASS DISTRIBUTIONS. (R826372)

    EPA Science Inventory

    We compare measurements of aerosol mass concentrations obtained gravimetrically using Teflon coated glass fiber filters and by integrating mass distributions measured with the differential mobility analyzer–aerosol particle mass analyzer (DMA–APM) technique (Aero...

  6. In Situ Measurements of Aerosol Mass Concentration and Spectral Absorption in Xianghe, SE of Beijing, China

    NASA Astrophysics Data System (ADS)

    Chaudhry, Z.; Martins, V.; Li, Z.

    2005-12-01

    China's rapid industrialization over the last few decades has affected air quality in many regions of China, and even the regional climate. As a part of the EAST-AIRE (East Asian Study of Tropospheric Aerosols: an International Regional Experiment) study, Nuclepore filters were collected in two size ranges (PM10 and PM2.5) at 12 hour intervals since January 2005 at Xianghe, about 70 km southeast of Beijing. Each filter was analyzed for mass concentration, aerosol scattering and absorption efficiencies. Mass concentrations during the winter months (January-March) ranged from 9 to 459 μg/m3 in the coarse mode with an average concentration of 122 μg/m3, and from 11 to 203 μg/m3 in the fine mode with an average concentration of 45 μg/m3. While some of the extreme values are likely linked to local emissions, regional air pollution episodes also played important roles. Absorption efficiency measurements at 550 nm show very high values compared to measurements performed in the United States during the CLAMS experiment. The spectral mass absorption efficiency was measured from 350 to 2500 nm and shows large differences between the absorption properties of soil dust, black carbon, and organic aerosols. The strong spectral differences observed can be related to differences in refractive indices from the several collected species and particle size effects. The absorption properties from aerosols measured in China show large absorption efficiencies, compared to aerosols measured in the US, possibly linked to different technology practices used in these countries. For organic plus black carbon aerosols, where the refractive index seems to be relatively constant, the absorption efficiency spectral dependence for fine mode aerosols falls between 1/λ and 1/λ2. The coarse mode absorption shows much less spectral dependence.

  7. Gas-phase CO2 subtraction for improved measurements of the organic aerosol mass concentration and oxidation degree by an aerosol mass spectrometer.

    PubMed

    Collier, S; Zhang, Q

    2013-12-17

    The Aerodyne aerosol mass spectrometer (AMS) has been widely used for real-time characterization of the size-resolved chemical composition of sub-micrometer aerosol particles. The first step in AMS sampling is the pre-concentration of aerosols while stripping away the gas-phase components, which contributes to the high sensitivity of this instrument. The strength of the instrument lies in particle phase measurement; however, ion signals generated from gas-phase species can influence the interpretation of the particle-phase chemistry data. Here, we present methods for subtracting the varying contributions of gas-phase carbon dioxide (CO2) in the AMS spectra of aerosol particles, which is critical for determining the mass concentration and oxygen-to-carbon (O/C) ratio of organic aerosol. This report gives details on the gaseous CO2 subtraction analysis performed on a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) data set acquired from sampling of fresh and diluted vehicle emissions. Three different methods were used: (1) collocated continuous gas-phase CO2 measurement coupled with periodic filter tests consisting of sampling the same particle-free air by the AMS and the CO2 analyzer, (2) positive matrix factorization (PMF) analysis to separate the gas- and particle-phase signals of CO2(+) at m/z 44, and (3) use of the particle time-of-flight (PTOF) size-resolved chemical information for separation of gas- and particle-phase signals at m/z 44. Our results indicate that these three different approaches yield internally consistent values for the gas/particle apportionment of m/z 44, but methods 2 and 3 require certain conditions to be met to yield reliable results. The methods presented are applicable to any situation where gas-phase components may influence the PM signal of interest.

  8. Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia

    NASA Astrophysics Data System (ADS)

    Chou, C. C.-K.; Hsu, W.-C.; Chang, S.-Y.; Chen, W.-N.; Chen, M.-J.; Huang, W.-R.; Huang, S.-H.; Tsai, C.-Y.; Chang, S.-C.; Lee, C.-T.; Liu, S.-C.

    2017-02-01

    This study investigated seasonal variations in the mass concentration and chemical composition of ambient aerosols observed at three stations (coastal, mountainous, and downtown sites) in northern Taiwan from March 2009 to February 2012. The results show that the major aerosol components include ammonium, sulfate, nitrate, sea salt, dust, organic carbon, and elemental carbon, whereas the mass fraction of each species depends on the sampling location and season. A significant correlation (r = 0.7-0.8) was observed in aerosol concentrations measured at the respective stations, indicating that aerosol concentrations were dominated by regional-scale factors. Ammonium, sulfate, and nitrate consistently reached respective peak values in the spring in conjunction with dust particle levels. This shows that the transport of dust and particulate air pollutants from the Asian continent has affected the atmospheric environment in this area. Distinct seasonality was observed for sea salt and secondary organic carbon (SOC): sea salt levels peaked in the autumn, whereas SOC levels peaked in the summer, implying that their sources were regulated by independent seasonal factors. Correlation between sea salt concentration and surface wind speed was derived from coastal measurements and showed a high value for the wind speed sensitivity parameter of around 0.37 for our location. In addition, it was revealed that the SOC concentration in aerosols was positively correlated with oxidant photolysis index (Ox × UVB), suggesting that the SOC seasonality was dominated by hydroxyl radical production.

  9. Fire and biofuel annual contributions to aerosol mass concentrations in the United States

    NASA Astrophysics Data System (ADS)

    Park, R. J.; Jacob, D. J.; Logan, J. A.

    2006-12-01

    Fires are a potentially major but poorly quantified factor for air quality degradation in the United States. Although episodic effects are well established, little attention has been paid to the more diffuse, nationwide effects of fires on seasonal and annual aerosol concentrations of relevance for air quality and visibility standards. Effects of biofuel use, both residential and industrial, have also received little attention. We use here correlations with non-soil potassium (ns-K) at the nationwide IMPROVE network of surface sites for 2001- 2004 to estimate total contributions to total carbonaceous (TC) aerosol concentrations from wildfires, prescribed fires, and residential and industrial biofuels. We find that the year-to-year variation of fires largely drives the observed interannual variability in TC. We present estimates of biomass burning contributions to regional aerosol concentrations in the western and eastern United States and further examine their implications for the national ambient air quality standard of fine aerosol concentrations and for the application of natural visibility condition by the U.S. EPA Regional Haze Rule.

  10. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  11. 40 CFR Table F-5 to Subpart F of... - Estimated Mass Concentration Measurement of PM 2.5 for Idealized “Typical” Coarse Aerosol Size...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Estimated Mass Concentration... 53—Estimated Mass Concentration Measurement of PM 2.5 for Idealized “Typical” Coarse Aerosol Size... Concentration (µg/m 3) Estimated Mass Concentration Measurement (µg/m 3) Ideal Sampler Fractional...

  12. 40 CFR Table F-5 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized “Typical” Coarse Aerosol Size...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Estimated Mass Concentration... 53—Estimated Mass Concentration Measurement of PM2.5 for Idealized “Typical” Coarse Aerosol Size... Concentration (µg/m3) Estimated Mass Concentration Measurement (µg/m3) Ideal Sampler Fractional...

  13. 40 CFR Table F-5 to Subpart F of... - Estimated Mass Concentration Measurement of PM 2.5 for Idealized “Typical” Coarse Aerosol Size...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Estimated Mass Concentration... 53—Estimated Mass Concentration Measurement of PM 2.5 for Idealized “Typical” Coarse Aerosol Size... Concentration (µg/m3) Estimated Mass Concentration Measurement (µg/m3) Ideal Sampler Fractional...

  14. Time-resolved mass concentration, composition and sources of aerosol particles in a metropolitan underground railway station

    NASA Astrophysics Data System (ADS)

    Salma, Imre; Weidinger, Tamás; Maenhaut, Willy

    Aerosol samples were collected using a stacked filter unit (SFU) for PM10-2.0 and PM2.0 size fractions on the platform of a metropolitan underground railway station in downtown Budapest. Temporal variations in the PM10 mass concentration and wind speed and direction were determined with time resolutions of 30 and 4 s using a tapered-element oscillating microbalance (TEOM) and a wind monitor, respectively. Sample analysis involved gravimetry for particulate mass, and particle-induced X-ray emission spectrometry (PIXE) for elemental composition. Diurnal variation of the PM10 mass concentration exhibited two peaks, one at approximately 07:00 h and the other at approximately 17:00 h. The mean±SD PM10 mass concentration for working hours was 155±55 μg m -3. Iron, Mn, Ni, Cu, and Cr concentrations were higher than in outdoor air by factors between 5 and 20, showing substantial enrichment compared to both the average crustal rock composition and the average outdoor aerosol composition. Iron accounted for 40% and 46% of the PM10-2.0 and PM2.0 masses, respectively, and 72% of the PM10 mass was associated with the PM10-2.0 size fraction. The aerosol composition in the metro station (in particular the abundance of the metals mentioned above) is quite different from the average outdoor downtown composition. Mechanical wear and friction of electric conducting rails and bow sliding collectors, ordinary rails and wheels, as well as resuspension, were identified as the primary sources. Possible health implications based on comparison to various limit values and to data available for other underground railways are discussed.

  15. Asian aerosols in North America: Extracting the chemical composition and mass concentration of the Asian continental aerosol plume from long-term aerosol records in the western United States

    NASA Astrophysics Data System (ADS)

    Vancuren, Richard A.

    2003-10-01

    Empirical assessment of the frequency and intensity of dust transport from Asia to North America has found that the dust regularly impacts elevated sites in the western United States, revealing a pattern of consistent, frequent transport above the marine boundary layer. Using the dust as a marker for Asian transport, a subset of Asian-influenced samples was identified within a decade of routine aerosol samples from two sites in the western cordillera of North America: Crater Lake, Oregon, and Mount Lassen, California. This subset was used to guide a statistical analysis to isolate Asian aerosol against the "background" of local contaminants. The analysis was then generalized to all samples during the transport season (March-October) for 1989-1999. A mixture of dust and combustion products dominates the Asian aerosol with typical concentration around 5 μg/m3 and mass median diameter between 2 and 3 μm. Major fine particle (<2.5 μm diameter) constituent fractions are ˜30% mineral, 28% organic compounds, 4% elemental carbon, 10% sulfate, <5% nitrate, and <1% sea salt. A second, possibly Asian, component of aged biomass smoke and sea salt is also present, with typical concentration (when present) around 1.5 μg/m3. Averaged over the transport season the dusty Asian aerosol and the smoky aerosol comprise 60 and 6%, respectively, of total particle mass (<10 μm diameter) and 72 and 13% of fine particle mass at these sites. These data indicate that the Asian continental plume is a significant contributor to aerosol loading at remote high-altitude sites across western North America. This implies a significant influence for Asian emissions on free troposphere aerosols over North America and suggests that they need to be explicitly accounted for in aerosol analyses ranging from climate studies to aerosol regulatory programs.

  16. 40 CFR Table F-4 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized Coarse Aerosol Size Distribution

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Estimated Mass Concentration... Concentration Measurement of PM2.5 for Idealized Coarse Aerosol Size Distribution Particle Aerodynamic Diameter (µm) Test Sampler Fractional Sampling Effectiveness Interval Mass Concentration (µg/m3) Estimated...

  17. 40 CFR Table F-4 to Subpart F of... - Estimated Mass Concentration Measurement of PM 2.5 for Idealized Coarse Aerosol Size Distribution

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Estimated Mass Concentration... Concentration Measurement of PM 2.5 for Idealized Coarse Aerosol Size Distribution Particle Aerodynamic Diameter (µm) Test Sampler Fractional Sampling Effectiveness Interval Mass Concentration (µg/m 3)...

  18. 40 CFR Table F-6 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized Fine Aerosol Size Distribution

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Estimated Mass Concentration... Concentration Measurement of PM2.5 for Idealized Fine Aerosol Size Distribution Particle Aerodynamic Diameter (µm) Test Sampler Fractional Sampling Effectiveness Interval Mass Concentration (µg/m3) Estimated...

  19. 40 CFR Table F-4 to Subpart F of... - Estimated Mass Concentration Measurement of PM 2.5 for Idealized Coarse Aerosol Size Distribution

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Estimated Mass Concentration... Concentration Measurement of PM 2.5 for Idealized Coarse Aerosol Size Distribution Particle Aerodynamic Diameter (µm) Test Sampler Fractional Sampling Effectiveness Interval Mass Concentration (µg/m3) Estimated...

  20. 40 CFR Table F-6 to Subpart F of... - Estimated Mass Concentration Measurement of PM 2.5 for Idealized Fine Aerosol Size Distribution

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Estimated Mass Concentration... Concentration Measurement of PM 2.5 for Idealized Fine Aerosol Size Distribution Particle Aerodynamic Diameter (µm) Test Sampler Fractional Sampling Effectiveness Interval Mass Concentration (µg/m 3)...

  1. 40 CFR Table F-6 to Subpart F of... - Estimated Mass Concentration Measurement of PM 2.5 for Idealized Fine Aerosol Size Distribution

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Estimated Mass Concentration... Concentration Measurement of PM 2.5 for Idealized Fine Aerosol Size Distribution Particle Aerodynamic Diameter (µm) Test Sampler Fractional Sampling Effectiveness Interval Mass Concentration (µg/m3) Estimated...

  2. The Potential of The Synergy of Sunphotometer and Lidar Data to Validate Vertical Profiles of The Aerosol Mass Concentration Estimated by An Air Quality Model

    NASA Astrophysics Data System (ADS)

    Siomos, N.; Filioglou, M.; Poupkou, A.; Liora, N.; Dimopoulos, S.; Melas, D.; Chaikovsky, A.; Balis, D. S.

    2016-06-01

    Vertical profiles of the aerosol mass concentration derived by the Lidar/Radiometer Inversion Code (LIRIC), that uses combined sunphotometer and lidar data, were used in order to validate the aerosol mass concentration profiles estimated by the air quality model CAMx. Lidar and CIMEL measurements performed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece (40.5N, 22.9E) from the period 2013-2014 were used in this study.

  3. Relationship and variations of aerosol number and PM 10 mass concentrations in a highly polluted urban environment—New Delhi, India

    NASA Astrophysics Data System (ADS)

    Mönkkönen, P.; Uma, R.; Srinivasan, D.; Koponen, I. K.; Lehtinen, K. E. J.; Hämeri, K.; Suresh, R.; Sharma, V. P.; Kulmala, M.

    Measurements of the aerosol number concentration and the PM 10 mass concentrations of urban background aerosols in different seasons were performed in New Delhi 2002, including the simultaneous measurements of NO 2, SO 2 and CO concentrations. The results indicate an interesting relationship between the aerosol number and the PM 10 mass concentrations. The number concentration increases with the mass concentration up to 300 μg m -3. However, after this point, the number concentration decreases even if the mass concentration increases. An explanation for this nonlinear behavior is proposed through a dynamic model involving the coagulation sink concept. The linear relationship between the mass and the number concentration in ambient air is valid if the mass concentration is relatively low. A high sink, however, means that the number concentration cannot be high—resulting in a decline in the number vs. mass plot. Clear diurnal, weekly and seasonal variations in concentrations were observed. High number concentrations of aerosols were observed in the mornings (7-8 a.m.) and in the evenings (7-10 p.m.). The number concentration was highest in March and lowest in June and the mass concentration was highest in November and lowest in June. The number concentration was higher during weekdays, but the mass concentration was higher during weekends. The number concentration correlates with the NO 2 concentration, which indicates that one major source of aerosol particles for the monitored site in New Delhi may be vehicular emission, but also domestic use of fossil fuels and biofuels cannot be neglected.

  4. In Situ Measurements of Aerosol Mass Concentration and Spectral Absorption at Three Location in and Around Mexico City

    NASA Astrophysics Data System (ADS)

    Chaudhry, Z.; Martins, V.; Li, Z.

    2006-12-01

    As a result of population growth and increasing industrialization, air pollution in heavily populated urban areas is one of the central environmental problems of the century. As a part of the MILAGRO (Megacity Initiative: Local and Global Research Observations) study, Nuclepore filters were collected in two size ranges (PM10 and PM2.5) at 12 hour intervals at three location in Mexico during March, 2006. Sampling stations were located at the Instituto Mexicano del Petroleo (T0), at the Rancho La Bisnago in the State of Hidalgo (T2) and along the Gulf Coast in Tampico (Tam). Each filter was analyzed for mass concentration, aerosol scattering and absorption efficiencies. Mass concentrations at T0 ranged from 47 to 179 μg/m3 for PM10 with an average concentration of 96 μg/m3, and from 20 to 93 μg/m3 for PM2.5 with an average concentration of 41 μg/m3. Mass concentrations at T2 ranged from 12 to 154 μg/m3 for PM10 with an average concentration of 51 μg/m3, and from 7 to 50 μg/m3 for PM2.5 with an average concentration of 25 μg/m3. Mass concentrations at Tam ranged from 34 to 80 μg/m3 for PM10 with an average concentration of 52 μg/m3, and from 8 to 23 μg/m3 for PM2.5 with an average concentration of 13 μg/m3. While some of the extreme values are likely linked to local emissions, regional air pollution episodes also played important roles. Each of the sampling stations experienced a unique atmospheric condition. The site at T0 was influenced by urban air pollution and dust storms, the site at T2 was significantly less affected by air pollution but more affected by regional dust storms and local dust devils while Tam was influenced by air pollution, dust storms and the natural marine environment. The spectral mass absorption efficiency was measured from 350 to 2500 nm and shows large differences between the absorption properties of soil dust, black carbon, and organic aerosols. The strong spectral differences observed can be related to differences in

  5. Detection of Free Tropospheric Air Masses With High So2 and Aerosol Concentrations: Evidence For New Aerosol Particle Formation By H2so4/h2o Nucleation

    NASA Astrophysics Data System (ADS)

    Katragkou, E.; Wilhelm, S.; Kiendler, A.; Arnold, F.; Minikin, A.; Schlager, H.; van Velthoven, P.

    Sulfur dioxide and aerosol measurements were performed in the free troposphere (FT) and the Planetary Boundary Layer (PBL) above continental Europe. The measure- ments took place on board of the German research aircraft "Falcon" in 18 April 2001 as a part of the SCAVEX campaign. A novel aircraft based CIMS (Chemical Ion- ization Mass Spectrometry) instrument equipped with an ion trap mass spectrometer (ITMS) with a low detection limit (50pptv) and a high time resolution (1.3s) operated by MPI-K was used to perform the SO2 measurements. For the aerosol measurements DLR-IPA operated a Condensation Particle Size Analyzer, detecting particles with diameters d > 4, 7, 9 and 20nm and a PCASP-100X aerosol spectrometer probe (d > 100nm). In the measurements made mostly around 5000m altitude SO2 rich air masses were occasionally observed with SO2 VMR of up to 2900pptv. The strong SO2 pollu- tion was due to fast vertical transport of polluted continental PBL air and small-scale deep convection, as indicated by the 5-day backward 3D trajectories. These observa- tions of strong SO2 pollution have interesting implications for aerosol processes, in- cluding efficient formation of gaseous sulfuric acid (GSA) and new aerosol particles. They also imply fast growth of freshly nucleated aerosol particles, which increases the chance for new particles to grow to the size of a CCN. Our analysis indicates the occurrence of new particle formation by H2SO4/H2O nucleation and fast new particle growth by H2SO4/H2O condensation and self-coagulation in the different air masses encountered during the flight.

  6. Size segregated mass concentration and size distribution of near surface aerosols over a tropical Indian semi-arid station, Anantapur: Impact of long range transport.

    PubMed

    Raghavendra Kumar, K; Narasimhulu, K; Balakrishnaiah, G; Suresh Kumar Reddy, B; Rama Gopal, K; Reddy, R R; Moorthy, K Krishna; Suresh Babu, S

    2009-10-15

    Regular measurements of size segregated as well as total mass concentration and size distribution of near surface composite aerosols, made using a ten-channel Quartz Crystal Microbalance (QCM) cascade impactor during the period of September 2007-May 2008 are used to study the aerosol characteristics in association with the synoptic meteorology. The total mass concentration varied from 59.70+/-1.48 to 41.40+/-1.72 microg m(-3), out of which accumulation mode dominated by approximately 50%. On a synoptic scale, aerosol mass concentration in the accumulation (submicron) mode gradually increased from an average low value of approximately 26.92+/-1.53 microg m(-3) during the post monsoon season (September-November) to approximately 34.95+/-1.32 microg m(-3) during winter (December-February) and reaching a peak value of approximately 43.56+/-1.42 microg m(-3) during the summer season (March-May). On the contrary, mass concentration of aerosols in the coarse (supermicron) mode increased from approximately 9.23+/-1.25 microg m(-3)during post monsoon season to reach a comparatively high value of approximately 25.89+/-1.95 microg m(-3) during dry winter months and a low value of approximately 8.07+/-0.76 microg m(-3) during the summer season. Effective radius, a parameter important in determining optical (scattering) properties of aerosol size distribution, varied between 0.104+/-0.08 microm and 0.167+/-0.06 microm with a mean value of 0.143+/-0.01 microm. The fine mode is highly reduced during the post monsoon period and the large and coarse modes continue to remain high (replenished) so that their relative dominance increases. It can be seen that among the two parameters measured, correlation of total mass concentration with air temperature is positive (R(2)=0.82) compared with relative humidity (RH) (R(2)=0.75).

  7. Long-Term Observations on Aerosol Elemental Carbon and Mass Concentrations in Winter-Time in New Delhi: Implications for Local Source Changes

    NASA Astrophysics Data System (ADS)

    Aggarwal, S. G.; Singh, K.; Singh, N.; Gupta, P. K.

    2009-12-01

    Fossil-fuel and bio-fuel burning are the two major sources identified for high carbonaceous aerosol loadings in several mega cities in India. In the last decade, according to a report from the Central Pollution Control Board (CPCB, 1999), the vehicular emission (mostly diesel-powered engines) was contributed to ~67% of the total air pollution load in New Delhi. Therefore, a policy decision was taken by the government, and most of the diesel-powered engines were converted to compressed natural gas (CNG) -powered engines by 2003. To better understand the effect of these changes on air quality, we collected high volume aerosol samples (total suspended particles, TSP) mostly for a day basis at our institute building in New Delhi almost everyday during winter season (November to January) from 2002 to 2008. We found very high mean aerosol loading, i.e., 488±47 μg m-3 in 2002 winter, which dropped significantly to 280±73 μg m-3 in 2003 winter. Thereafter, a steadily increased trend of aerosol mass loadings was observed, i.e., 339±112, 339±120, 412±107 and 444±55 μg m-3 in 2004, 2005, 2006 and 2007 winters, respectively. Similar trend was also observed for elemental carbon (EC) concentration in TSP, which was peaked in 2002 (47±11 μg m-3) and minimized in 2003 (32±6 μg m-3), and then gradually increased to 41±8 μg m-3 in 2007 winter. These decline trends of aerosol mass and EC concentrations in 2003 can be explained well, because of the conversion of diesel engine to CNG engines of public transport facilities. However, again increase in aerosol mass and EC concentrations possibly because of a high increase in road traffic in recent years. According to the economic survey of New Delhi 2008-09, the number of vehicles (which includes all types of engines, i.e., petrol, diesel and CNG) has grown from ~3.3 millions in 1997-98 to ~5.6 millions in 2007-08. The influence of engine types and vehicle population on aerosol loading can also be explained well by SO2 and

  8. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration

    PubMed Central

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H.; Henry, Mike; Baden, Daniel G.

    2009-01-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1 h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5–10 μg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m3. The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction. PMID:19879288

  9. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration.

    PubMed

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H; Henry, Mike; Baden, Daniel G

    2010-05-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5-10 microg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m(3). The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction.

  10. 40 CFR Table F-4 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized Coarse Aerosol Size Distribution

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Estimated Mass Concentration Measurement of PM2.5 for Idealized Coarse Aerosol Size Distribution F Table F-4 to Subpart F of Part 53... Equivalent Methods for PM2.5 Pt. 53, Subpt. F, Table F-4 Table F-4 to Subpart F of Part 53—Estimated...

  11. 40 CFR Table F-5 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized “Typical” Coarse Aerosol Size...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Estimated Mass Concentration Measurement of PM2.5 for Idealized âTypicalâ Coarse Aerosol Size Distribution F Table F-5 to Subpart F of Part... of Class II Equivalent Methods for PM2.5 Pt. 53, Subpt. F, Table F-5 Table F-5 to Subpart F of...

  12. 40 CFR Table F-6 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized Fine Aerosol Size Distribution

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Estimated Mass Concentration Measurement of PM2.5 for Idealized Fine Aerosol Size Distribution F Table F-6 to Subpart F of Part 53... Equivalent Methods for PM2.5 Pt. 53, Subpt. F, Table F-6 Table F-6 to Subpart F of Part 53—Estimated...

  13. 40 CFR Table F-4 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized Coarse Aerosol Size Distribution

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Estimated Mass Concentration Measurement of PM2.5 for Idealized Coarse Aerosol Size Distribution F Table F-4 to Subpart F of Part 53... Equivalent Methods for PM2.5 Pt. 53, Subpt. F, Table F-4 Table F-4 to Subpart F of Part 53—Estimated...

  14. 40 CFR Table F-5 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized “Typical” Coarse Aerosol Size...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Estimated Mass Concentration Measurement of PM2.5 for Idealized âTypicalâ Coarse Aerosol Size Distribution F Table F-5 to Subpart F of Part... of Class II Equivalent Methods for PM2.5 Pt. 53, Subpt. F, Table F-5 Table F-5 to Subpart F of...

  15. 40 CFR Table F-6 to Subpart F of... - Estimated Mass Concentration Measurement of PM2.5 for Idealized Fine Aerosol Size Distribution

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Estimated Mass Concentration Measurement of PM2.5 for Idealized Fine Aerosol Size Distribution F Table F-6 to Subpart F of Part 53... Equivalent Methods for PM2.5 Pt. 53, Subpt. F, Table F-6 Table F-6 to Subpart F of Part 53—Estimated...

  16. Long-term comparative study of columnar and surface mass concentration aerosol properties in a background environment

    NASA Astrophysics Data System (ADS)

    Bennouna, Y. S.; Cachorro, V. E.; Mateos, D.; Burgos, M. A.; Toledano, C.; Torres, B.; de Frutos, A. M.

    2016-09-01

    The relationship between columnar and surface aerosol properties is not a straightforward problem. The Aerosol Optical Depth (AOD), Ångström exponent (AE), and ground-level Particulate Matter (PMX, x = 10 or 2.5 μm) data have been studied from a climatological point of view. Despite the different meanings of AOD and PMx both are key and complementary quantities that quantify aerosol load in the atmosphere and many studies intend to find specific relationships between them. Related parameters such as AE and PM ratio (PR = PM2.5/PM10), giving information about the predominant particle size, are included in this study on the relationships between columnar and surface aerosol parameters. This study is based on long measurement records (2003-2014) obtained at two nearby background sites from the AERONET and EMEP networks in the north-central area of Spain. The climatological annual cycle of PMx shows two maxima along the year (one in late-winter/early-spring and another in summer), but this cycle is not followed by the AOD which shows only a summer maximum and a nearly bell shape. However, the annual means of both data sets show strong correlation (R = 0.89) and similar decreasing trends of 40% (PM10) and 38% (AOD) for the 12-year record. PM10 and AOD daily data are moderately correlated (R = 0.58), whereas correlation increases for monthly (R = 0.74) and yearly (R = 0.89) means. Scatter plots of AE vs. AOD and PR vs. PM10 have been used to characterize aerosols over the region. The PR vs. AE scatterplot of daily data shows no correlation due to the prevalence of intermediate-sized particles. As day-to-day correlation is low (especially for high turbidity events), a binned analysis was also carried out to establish consistent relationships between columnar and surface quantities, which is considered to be an appropriate approach for environmental and climate studies. In this way the link between surface concentrations and columnar remote sensing data is shown to

  17. Analysis of spatial and seasonal distributions of MODIS aerosol optical properties and ground-based measurements of mass concentrations in the Yellow Sea region in 2009.

    PubMed

    Kim, Hak-Sung; Chung, Yong-Seung; Lee, Sun-Gu

    2013-01-01

    Satellite-retrieved data on aerosol optical depth (AOD) and Ångström exponent (AE) using a moderate resolution imaging spectrometer (MODIS) were used to analyze large-scale distributions of atmospheric aerosols in East Asia. AOD was relatively high in March (0.44 ± 0.25) and low in September (0.24 ± 0.21) in the East Asian region in 2009. Sandstorms originating from the deserts and dry areas in northern China and Mongolia were transported on a massive scale during the springtime, thus contributing to the high AOD in East Asia. However, whereas PM10 with diameters ≤10 μm was the highest in February at Anmyon, Cheongwon, and Ulleung, located leeward about halfway through the Korean Peninsula, AOD rose to its highest in May. The growth of hygroscopic aerosols attendant on increases in relative humidity prior to the Asian monsoon season contributed to a high AOD level in May. AE typically appears at high levels (1.30 ± 0.37) in August due to anthropogenic aerosols originating from the industrial areas in eastern China, while AOD stays low in summer due to the removal process caused by rainfall. The linear correlation coefficients of the MODIS AOD and ground-based mass concentrations of PM10 at Anmyon, Cheongwon, and Ulleung were measured at 0.4~0.6. Four cases (6 days) of mineral dustfall from sandstorms and six cases (12 days) of anthropogenically polluted particles were observed in the central area of the Korean Peninsula in 2009. PM10 mass concentrations increased at both Anmyon and Cheongwon in the cases of mineral dustfall and anthropogenically polluted particles. Cases of dustfall from sandstorms and anthropogenic polluted particles, with increasing PM10 mass concentrations, showed higher AOD values in the Yellow Sea region.

  18. Synchronised Aerosol Mass Spectrometer Measurements across Europe

    NASA Astrophysics Data System (ADS)

    Nemitz, Eiko

    2010-05-01

    Up to twelve Aerodyne Aerosol Mass Spectrometers (AMSs) were operated simultaneously at rural and background stations (EMEP and EUSAAR sites) across Europe. Measurements took place during three intensive periods, in collaboration between the European EUCAARI IP and the EMEP monitoring activities under the UNECE Convention for Long-Range Transboundary Air Pollution (CLRTAP) during three contrasting months (May 2008, Sep/Oct 2008, Feb/Mar 2009). These measurements were conducted, analysed and quality controlled carefully using a unified protocol, providing the largest spatial database of aerosol chemical composition measured with a unified online technique to date, and a unique snapshots of the European non-refractory submicron aerosol climatology. As campaign averages over all active monitoring sites, organics represent 28 to 43%, sulphate 18 to 25%, ammonium 13 to 15% and nitrate 15 to 36% of the resolved aerosol mass, with the highest relative nitrate contribution during the Feb/Mar campaign. The measurements demonstrate that in NW Europe (e.g. Ireland, UK, The Netherlands, Germany, Switzerland) the regional submicron aerosol tends to be neutralised and here nitrates make a major contribution to the aerosol mass. By contrast, periods with low nitrate and acidic aerosol were observed at sites in S and E Europe (e.g. Greece, Finland), presumably due to a combination of larger SO2 point sources in Easter Europe, smaller local NH3 sources and, in the case of Greece, higher temperatures. While at the more marine and remote sites (Ireland, Scotland, Finland) nitrate concentrations were dominated by episodic transport phenomena, at continental sites (Switzerland, Germany, Hungary) nitrate followed a clear diurnal cycle, reflecting the thermodynamic behaviour of ammonium nitrate. The datasets clearly shows spatially co-ordinated, large-scale pollution episodes of organics, sulphate and nitrate, the latter being most pronounced during the Feb/Mar campaign. At selected

  19. Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MSn) for measuring organic acids in concentrated bulk aerosol - a laboratory and field study

    NASA Astrophysics Data System (ADS)

    Vogel, A. L.; Äijälä, M.; Brüggemann, M.; Ehn, M.; Junninen, H.; Petäjä, T.; Worsnop, D. R.; Kulmala, M.; Williams, J.; Hoffmann, T.

    2012-08-01

    The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS) at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was increased by a factor of 7.5 to 11 (e.g. ~40 ng m-3 for pinonic acid) by using the miniature Versatile Aerosol Concentration Enrichment System (mVACES) upstream of the mass spectrometer. The APCI-IT-MS was calibrated in the negative ion mode with two biogenic organic acid standards - pinic acid and pinonic acid. Pinic acid was used as a surrogate for the quantification of the total amount of organic acids in the ambient aerosol based on the total signal intensities in the negative ion mode. The results were compared with the total organic signal of a C-ToF-AMS during the HUMPPA-COPEC 2010 field campaign. The campaign average contribution of organic acids measured by APCI-IT-MS to the total sub-micron organic aerosol mass was estimated to be about 60%. Very good correlation between APCI-IT-MS and C-ToF-AMS (Pearson's R = 0.94) demonstrates soft ionization mass spectrometry as a complimentary technique to AMS with electron impact ionization. MS2 studies of specific m/z ratios recorded during the HUMPPA-COPEC 2010 field campaign were compared to MS2 studies of selected monoterpene oxidation products formed in simulation chamber experiments. The comparison of the resulting fragments shows that oxidation products of the main VOCs emitted at Hyytiälä (α-pinene and Δ3-carene) cannot account for all of the measured fragments, which illustrates the complexity of ambient aerosol and possibly indicates unidentified or underestimated biogenic SOA precursor in the boreal forest.

  20. Boundary layer aerosol size distribution, mass concentration and mineralogical composition in Morocco and at Cape Verde Islands during SAMUM I-II

    NASA Astrophysics Data System (ADS)

    Kandler, K.; Lieke, K.

    2009-04-01

    The Saharan Mineral Dust Experiment (SAMUM) is dedicated to the understanding of the radiative effects of mineral dust. Two major field experiments were performed: A first joint field campaign took place at Ouarzazate and near Zagora, southern Morocco, from May 13 to June 7, 2006. Aircraft and ground based measurements of aerosol physical and chemical properties were carried out to collect a data set of surface and atmospheric columnar information within a major dust source. This data set combined with satellite data provides the base of the first thorough columnar radiative closure tests in Saharan dust. A second field experiment was conducted during January-February 2008, in the Cape Verde Islands region, where about 300 Tg of mineral dust are transported annually from Western Africa across the Atlantic towards the Caribbean Sea and the Amazon basin. Along its transport path, the mineral dust is expected to influence significantly the radiation budget - by direct and indirect effects - of the subtropical North Atlantic. We are lacking a radiative closure in the Saharan air plume. One focus of the investigation within the trade wind region is the spatial distribution of mixed dust/biomass/sea salt aerosol and their physical and chemical properties, especially with regard to radiative effects. We report on measurements of size distributions, mass concentrations and mineralogical composition conducted at the Zagora (Morocco) and Praia (Cape Verde islands) ground stations. The aerosol size distribution was measured from 20 nm to 500

  1. Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MSn) for measuring organic acids in concentrated bulk aerosol - a laboratory and field study

    NASA Astrophysics Data System (ADS)

    Vogel, A. L.; Äijälä, M.; Brüggemann, M.; Ehn, M.; Junninen, H.; Petäjä, T.; Worsnop, D. R.; Kulmala, M.; Williams, J.; Hoffmann, T.

    2013-02-01

    The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS) at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft-ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was improved by a factor of 7.5 to 11 (e.g. ∼40 ng m3 for pinonic acid) by using the miniature versatile aerosol concentration enrichment system (mVACES) upstream of the mass spectrometer. The APCI-IT-MS was calibrated in the negative ion mode with two biogenic organic acid standards - pinic acid and pinonic acid. Pinic acid was used as a surrogate for the quantification of the total amount of organic acids in the ambient aerosol based on the total signal intensities in the negative ion mode. The results were compared with the total organic signal of a C-ToF-AMS during the HUMPPA-COPEC 2010 field campaign. The campaign average contribution of organic acids measured by APCI-IT-MS to the total submicron organic aerosol mass was estimated to be about 60%, based on the response of pinic acid. Very good correlation between APCI-IT-MS and C-ToF-AMS (Pearson's R = 0.94) demonstrates soft-ionization mass spectrometry as a complimentary technique to AMS with electron impact ionization. MS2 studies of specific m/z ratios recorded during the HUMPPA-COPEC 2010 field campaign were compared to MS2 studies of selected monoterpene oxidation products formed in simulation chamber experiments. The comparison of the resulting fragments shows that oxidation products of the main VOCs emitted at Hyytiälä (α-pinene and Δ3-carene) cannot account for all of the measured fragments. Possible explanations for those unaccounted fragments are the presence of unidentified or underestimated biogenic SOA precursors, or that different products are formed by a different oxidant

  2. A method for retrieving vertical distribution of aerosol mass concentration in atmosphere from results of lidar sensing at Nd:YAG laser wavelengths

    NASA Astrophysics Data System (ADS)

    Lisenko, S. A.; Kugeiko, M. M.

    2011-03-01

    A method for retrieving the vertical profiles of atmospheric aerosol concentration from the results of lidar sensing at Ng:YAG laser wavelengths is developed based on the found multiple regressions between the optical location characteristics of aerosol at wavelengths of 0.355, 0.532, and 1.064 nm, as well as between the aerosol backscattering coefficient at these wavelengths and the concentration of aerosol particles. The method does not require solving ill-posed inverse problems and minimizes the use of a priori information. The reliability and generality of regressions obtained are confirmed by their good agreement with the AERO-NET data. The method efficiency is demonstrated by numerical experiments on retrieving profiles of back-scattering coefficients and concentration that corresponds to different optical models of aerosol.

  3. Determination of aerosol ammonium using an aerodyne aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Delia, A. E.; Toohey, D. W.; Worsnop, D. R.

    2003-04-01

    The chemical composition of fine aerosols is a significant issue both because it influences the chemical and radiative properties of the aerosols, which in turn impact the regional and global climate and human health, and because it is difficult to measure accurately. The Aerosol Mass Spectrometer (AMS) developed by Aerodyne Research measures both chemical composition and aerodynamic size of submicron aerosols quantitatively. However, the measurement of aerosol ammonium is more difficult than that of the other major inorganic species, nitrate and sulfate, because of interferences in the mass spectrum from air and water. This presentation will describe the successful procedure developed for dealing with these interferences and accurately determining the ammonium mass. In addition, the application of this procedure to aerosols from a range of ambient conditions will be demonstrated using data from several field studies.

  4. Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN)

    NASA Astrophysics Data System (ADS)

    Birmili, Wolfram; Weinhold, Kay; Rasch, Fabian; Sonntag, André; Sun, Jia; Merkel, Maik; Wiedensohler, Alfred; Bastian, Susanne; Schladitz, Alexander; Löschau, Gunter; Cyrys, Josef; Pitz, Mike; Gu, Jianwei; Kusch, Thomas; Flentje, Harald; Quass, Ulrich; Kaminski, Heinz; Kuhlbusch, Thomas A. J.; Meinhardt, Frank; Schwerin, Andreas; Bath, Olaf; Ries, Ludwig; Gerwig, Holger; Wirtz, Klaus; Fiebig, Markus

    2016-08-01

    The German Ultrafine Aerosol Network (GUAN) is a cooperative atmospheric observation network, which aims at improving the scientific understanding of aerosol-related effects in the troposphere. The network addresses research questions dedicated to both climate- and health-related effects. GUAN's core activity has been the continuous collection of tropospheric particle number size distributions and black carbon mass concentrations at 17 observation sites in Germany. These sites cover various environmental settings including urban traffic, urban background, rural background, and Alpine mountains. In association with partner projects, GUAN has implemented a high degree of harmonisation of instrumentation, operating procedures, and data evaluation procedures. The quality of the measurement data is assured by laboratory intercomparisons as well as on-site comparisons with reference instruments. This paper describes the measurement sites, instrumentation, quality assurance, and data evaluation procedures in the network as well as the EBAS repository, where the data sets can be obtained (doi:10.5072/guan).

  5. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

    NASA Astrophysics Data System (ADS)

    Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

    2016-02-01

    Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between simulations and observations of

  6. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern Pyrenees, 1570 m a.s.l.)

    NASA Astrophysics Data System (ADS)

    Ripoll, A.; Pey, J.; Minguillón, M. C.; Pérez, N.; Pandolfi, M.; Querol, X.; Alastuey, A.

    2014-04-01

    Time variation of mass particulate matter (PM1 and PM1&minus10), black carbon (BC) and number of particles (N3: number of particles with an aerodynamic diameter higher than 3 nm, and N10: higher than 10 nm) concentrations at the high-altitude site of Montsec (MSC) in the southern Pyrenees was interpreted for the period 2010-2012. At MSC, PM10 (12 μg m-3) and N7 (2140 # cm-3) three-year arithmetic average concentrations were higher than those measured at other high-altitude sites in central Europe during the same period (PM10: 3-9 μg m-3 and N: 634-2070 # cm-3). By contrast, BC concentrations at MSC (0.2 μg m-3) were equal to or even lower than those measured at these European sites (0.2-0.4 μg m-3). These differences were attributed to the higher relevance of Saharan dust transport and to the higher importance of the biogenic precursor emissions and new particle formation (NPF) processes, and to the lower influence of anthropogenic emissions at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African air outbreaks (PM1&minus10: 13 μg m-3, PM1: 8 μg m-3 and BC: 0.3 μg m-3) and low concentrations when Atlantic advections occurred (PM1-10: 5 μg m-3, PM1: 4 μg m-3 and BC: 0.1 μg m-3). PM and BC concentrations increased in summer, with a secondary maximum in early spring, and were at their lowest in winter, due to the contrasting origin of the air masses in the warmer seasons (spring and summer) and in the colder seasons (autumn and winter). The maximum in the warmer seasons was attributed to long-range transport processes that mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles, with maxima at midday in the

  7. Three years of aerosol mass, black carbon and particle number concentrations at Montsec (southern~Pyrenees, 1570 m a.s.l.)

    NASA Astrophysics Data System (ADS)

    Ripoll, A.; Pey, J.; Minguillón, M. C.; Pérez, N.; Pandolfi, M.; Querol, X.; Alastuey, A.

    2013-10-01

    Time variation of mass particulate matter (PM1 and PM1-10), black carbon (BC) and particle number (N) concentrations at the high altitude site of Montsec (MSC) in the southern Pyrenees was interpreted for the period 2010-2012. The MSC site registered higher PM10 (12 μg m-3) and N > 7 nm (2209 # cm-3) concentrations than those measured at other high altitude sites in central Europe (PM10: 3-9 μg m-3 and N: 634-2070 # cm-3). By contrast, BC concentrations at MSC (0.2 μg m-3) were equal or even lower than those measured at these European sites (0.2-0.4 μg m-3). These differences were attributed to the lower influence of anthropogenic emissions and to the higher relevance of Saharan dust transport and new particle formation (NPF) processes at MSC. The different time variation of PM and BC concentrations compared with that of N suggests that these aerosol parameters were governed by diverse factors at MSC. Both PM and BC concentrations showed marked differences for different meteorological scenarios, with enhanced concentrations under North African outbreaks (PM1-10: 13 μg m-3, PM1: 8 μg m-3 and BC: 0.3 μg m-3) and low concentrations when Atlantic advections occurred (PM1-10: 5 μg m-3, PM1: 4 μg m-3 and BC: 0.1 μg m-3). Because of the contrasting origin of the air masses in the warmer seasons (spring and summer) and in the colder seasons (autumn and winter), PM and BC concentrations showed a marked increase in summer, with a secondary maximum in early spring, and were at their lowest during winter. The maximum in the warmer seasons was attributed to long-range transport processes which mask the breezes and regional transport breaking the daily cycles of these pollutants. By contrast, PM and BC concentrations showed clear diurnal cycles with maxima at midday in the colder seasons. A statistically significant weekly variation was also obtained for the BC concentrations, displaying a progressive increase from Tuesday to Saturday, followed by a significant

  8. Calibration of PM2.5 mass concentrations used in the Pittsburgh Aerosol Research and Inhalation Epidemiology Study

    NASA Astrophysics Data System (ADS)

    Bilonick, Richard A.; Connell, Daniel P.; Talbott, Evelyn O.; Xue, Tao; Rager, Judith R.

    2015-08-01

    Fifteen different types of PM2.5 mass concentration samplers were used by seven different monitoring networks at 47 locations in the Pittsburgh, Pennsylvania, region from 1999 to 2008. The samplers included Federal Reference Method (FRM) samplers, speciation samplers, tapered element oscillating microbalance (TEOM) samplers, and others. The different measurement principles used in these designs tended to lead to systematic differences (biases) when measuring the same quantity, and to differences in the typical size of random errors (imprecision) introduced by each type of sampler. Bias can take different forms either as a constant bias or as a non-constant (scale) bias, which depends on the size of the quantity being measured. The objective of the work presented here was to simultaneously calibrate the measurements made by these different samplers to remove relative biases (both constant and non-constant) so that all of the available PM2.5 data could be used interchangeably to develop exposure estimates for a retrospective epidemiology study. In order to accomplish this, we used linked temperature-stratified structural equation models, nonlinear regression models, and nonlinear mixed effects models. Applying these methods we constructed a comprehensive measurement error model that included both systematic error and random error components, and derived calibration equations that can be applied to place all of the PM2.5 mass concentration measurements on the same scale. The FRM sampler was used as the reference scale although the parameter estimates are invariant to this choice. Results showed that: (1) 50 °C TEOM samplers tended to show a large downward bias relative to the FRM sampler at low temperatures, and the magnitude of this bias decreased according to a nonlinear (sigmoidal) pattern with increasing temperature, (2) speciation samplers and other integrated samplers generally showed smaller biases relative to the FRM sampler that were not temperature

  9. Intercomparison between a single particle soot photometer and evolved gas analysis in an industrial area in Japan: Implications for the consistency of soot aerosol mass concentration measurements

    NASA Astrophysics Data System (ADS)

    Miyakawa, T.; Kanaya, Y.; Komazaki, Y.; Taketani, F.; Pan, X.; Irwin, M.; Symonds, J.

    2016-02-01

    Mass concentrations of soot (typically comprising black and elemental carbon; BC and EC, respectively) aerosols, were measured at Yokosuka city, an industrial region in Japan in the early summer of 2014. The results of laser-induced incandescence (LII) and evolved gas analysis (EGA) techniques were compared using a single particle soot photometer (SP2) and semi-continuous elemental/organic carbon analyzer (EC/OC analyzer), respectively. We revisited the procedure of SP2 calibration with a focus on investigating the relationship between LII intensity (SLII) and refractory BC (rBC) mass per particle (mPP) for some BC-proxies in the laboratory, as well as for ambient rBC particles in order to discuss the uncertainty of the SP2. It was found that the mPP-SLII for the fullerene soot and carbon black particles agreed well within 3% and 10%, respectively, with that for ambient rBC particles. This is the first time to suggest the use of carbon black as a reference material. We also found that the mPP-SLII for the aqueous deflocculated Acheson graphite particles with the correction factor given by Baumgardner et al. (2012) was still biased by around +20% to that for ambient rBC particles. EC quantified by the semi-continuous EC/OC analyzer using a thermal-protocol similar to that of Interagency Monitoring of Protected Visual Environments (IMPROVE-like), systematically showed higher concentrations than rBC measured by the SP2. The uncertainties related to SP2 cannot fully account for this difference. This result was likely caused by the contribution of charred organic materials to EC, which can be affected significantly by thermal-protocols for the EGA. The consistency and differences between rBC and EC are discussed with regard to comparing their respective mass concentrations.

  10. High Concentration Standard Aerosol Generator.

    DTIC Science & Technology

    1985-07-31

    materials. In addition to material problems, many liquids are extremely flammable or explosive when aerosolized. This can be checked by putting a small...Hochriner. D. (1975) Stub 3A 440-445. St6ber, W. Flachsbart, H. and Hochramn, D. (1970) Staub 3^, 277. Yoshida. H. Fujii, K. Yomimoto, Y. Masuda. H. and

  11. Contribution of methane to aerosol carbon mass

    NASA Astrophysics Data System (ADS)

    Bianchi, F.; Barmet, P.; Stirnweis, L.; El Haddad, I.; Platt, S. M.; Saurer, M.; Lötscher, C.; Siegwolf, R.; Bigi, A.; Hoyle, C. R.; DeCarlo, P. F.; Slowik, J. G.; Prévôt, A. S. H.; Baltensperger, U.; Dommen, J.

    2016-09-01

    Small volatile organic compounds (VOC) such as methane (CH4) have long been considered non-relevant to aerosol formation due to the high volatility of their oxidation products. However, even low aerosol yields from CH4, the most abundant VOC in the atmosphere, would contribute significantly to the total particulate carbon budget. In this study, organic aerosol (OA) mass yields from CH4 oxidation were evaluated at the Paul Scherrer Institute (PSI) smog chamber in the presence of inorganic and organic seed aerosols. Using labeled 13C methane, we could detect its oxidation products in the aerosol phase, with yields up to 0.09

  12. Spatial and Temporal Variability of Outdoor Coarse Particulate Matter Mass Concentrations Measured with a New Coarse Particulate Sampler during the Detroit Exposure and Aerosol Research Study

    EPA Science Inventory

    The Detroit Exposure and Aerosol Research Study (DEARS) provided data to compare outdoor residential coarse particulate matter (PM10-2.5) concentrations in six different areas of Detroit with data from a central monitoring site. Daily and seasonal influences on the spa...

  13. Physicochemical characterization of Capstone depleted uranium aerosols I: uranium concentration in aerosols as a function of time and particle size.

    PubMed

    Parkhurst, Mary Ann; Cheng, Yung Sung; Kenoyer, Judson L; Traub, Richard J

    2009-03-01

    During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing DU were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time, particularly within the first minute after a shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s after perforation, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% after 30 min. The initial and maximum uranium concentrations were lower in the Bradley vehicle than those observed in the Abrams tank, and the concentration levels decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in a cyclone sampler, which collected aerosol continuously for 2 h after perforation. The percentages of uranium mass in the cyclone separator stages ranged from 38 to 72% for the Abrams tank with conventional armor. In most cases, it varied with particle size, typically with less uranium associated with the smaller particle sizes. Neither the Abrams tank with DU armor nor the Bradley vehicle results were specifically correlated with particle size and can best be represented by their average uranium mass concentrations of 65

  14. A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

    NASA Astrophysics Data System (ADS)

    Yuan, Renmin; Luo, Tao; Sun, Jianning; Liu, Hao; Fu, Yunfei; Wang, Zhien

    2016-04-01

    Atmospheric aerosol greatly influences human health and the natural environment, as well as the weather and climate system. Therefore, atmospheric aerosol has attracted significant attention from society. Despite consistent research efforts, there are still uncertainties in understanding its effects due to poor knowledge about aerosol vertical transport caused by the limited measurement capabilities of aerosol mass vertical transport flux. In this paper, a new method for measuring atmospheric aerosol vertical transport flux is developed based on the similarity theory of surface layer, the theory of light propagation in a turbulent atmosphere, and the observations and studies of the atmospheric equivalent refractive index (AERI). The results show that aerosol mass flux can be linked to the real and imaginary parts of the atmospheric equivalent refractive index structure parameter (AERISP) and the ratio of aerosol mass concentration to the imaginary part of the AERI. The real and imaginary parts of the AERISP can be measured based on the light-propagation theory. The ratio of the aerosol mass concentration to the imaginary part of the AERI can be measured based on the measurements of aerosol mass concentration and visibility. The observational results show that aerosol vertical transport flux varies diurnally and is related to the aerosol spatial distribution. The maximum aerosol flux during the experimental period in Hefei City was 0.017 mg m-2 s-1, and the mean value was 0.004 mg m-2 s-1. The new method offers an effective way to study aerosol vertical transport in complex environments.

  15. Ambient aerosol analysis using aerosol-time-of-flight mass spectrometry

    SciTech Connect

    Prather, K.A.; Noble, C.A.; Liu, D.Y.; Silva, P.J.; Fergenson, D.F.

    1996-10-01

    We have recently developed a technique, Aerosol-Time-of-Flight Mass Spectrometry (ATOFMS), which is capable of real-time determination of the aerodynamic size and chemical composition of individual aerosol particles. In order to obtain such information, the techniques of aerodynamic particle sizing and time-of-flight mass spectrometry are combined in a single instrument. ATOFMS is being used for the direct analysis of ambient aerosols with the goal of establishing correlations between particle size and chemical composition. Currently, measurements are being made to establish potential links between the presence of particular types of particles with such factors as the time of day, weather conditions, and concentration levels of gaseous smog components such as NO{sub x} and ozone. This data will be used to help establish a better understanding of tropospheric gas-aerosol processes. This talk will discuss the operating principles of ATOFMS as well as present the results of ambient analysis studies performed in our laboratory.

  16. Intercomparison of aerosol instruments: number concentration

    SciTech Connect

    Knutson, E O; Sinclair, D; Tu, K W; Hinchliffe, L; Franklin, H

    1982-05-01

    An intercomparison of aerosol instruments conducted February 23-27, 1981, at the Environmental Measurements Laboratory (EML) focused on five instruments: the Pollak and TSI condensation nucleus counters; the Active Scattering Aerosol Spectrometer (ASAS-X); and two aerosol electrometers. Test aerosols of sodium chloride and ammonium fluorescein generated by nebulization/electrostatic classification were used to obtain 195 lines of comparison data. Concentrations measured by the ASAS-X and the TSI aerosol electrometer averaged respectively 1.388 and 1.581 times that measured by the Pollak. These ratios were very stable during the week and there was little effect of particle size or material. Most other comparisons were equally stable. However, a review of past work at EML and elsewhere led to the disturbing conclusion that these ratios may change from year to year, or from season to season. A filter sample was taken from microscopy, concurrent with readings from the ASAS-X and the TSI condensation nucleus counters. In this sample, the two instruments differed by 20%. Within its 20% uncertainty, the filter result matched both the TSI and ASAS-X readings.

  17. Correlation of aerosol mass near the ground with aerosol optical depth during two seasons in Munich

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Harbusch, Andreas; Emeis, Stefan; Koepke, Peter; Wiegner, Matthias

    2008-06-01

    Relations of the aerosol optical depth (AOD) with aerosol mass concentration near the ground, particulate matter (PM), have been studied on the basis of measurements. The objective is with respect to possible remote sensing methods to get information on the spatial and temporal variation of aerosols which is important for human health effects. Worldwide the AOD of the atmospheric column is routinely monitored by sun-photometers and accessible from satellite measurements also. It is implied here that the AOD is caused mainly by attenuation processes within the mixing layer because this layer includes nearly all atmospheric aerosols. Thus the mixing layer height (MLH) is required together with the AOD, measured by ground-based sun-photometers (around 560 nm), to get information about aerosols near the ground. MLH is determined here from surface-based remote sensing. Investigations were performed during two measurement campaigns in and near Munich in May and November/December 2003 on the basis of daily mean values. Using AOD and MLH measurements the aerosol extinction coefficient of the mixing layer has been calculated. This quantity was correlated with the measured PM10, PM2.5 and PM1 mass concentrations near the ground by performing a linear regression and thus providing a mass extinction efficiency giving squares of the correlation coefficients (R2) between 0.48 (PM1 during summer campaign) and 0.90 (PM2.5 during winter campaign). These correlations suggest that the derived mass extinction efficiencies represent a statistically significant relation between the aerosol extinction coefficients and the surface-based PM mass concentrations mainly during winter conditions.

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  19. Size and concentration measurement of an industrial aerosol

    SciTech Connect

    O'Brien, D.; Baron, P.; Willeke, K.

    1986-07-01

    Several real-time particle sizing instruments were evaluated for measuring the size distribution and concentration of the aerosol produced during the high speed grinding of gray iron castings. Aerosol was sampled in the airstream entrained by the motion of a spinning grinding wheel in a pilot grinding operation. Measurement methods based on differing physical principles were selected for evaluation and compared: particle inertia (aerodynamic particle sizer and quartz crystal microbalance cascade impactor); light scattering (laser aerosol spectrometer); and projected-area microscopy (scanning electron microscope). Inferences of aerodynamic diameter based on measurements by the laser aerosol spectrometer consistently undersized that determined by the aerodynamic particle sizer by a factor of 1.5. Estimates of aerodynamic diameters from projected area diameters determined by scanning electron microscopy differed from those obtained by the aerodynamic particle sizer by a factor of 2. Differences appeared to be a non-linear function of particle diameter. Estimates of respirable mass determined from mass-weighted particle size spectra varied by a factor of 6 between the largest estimate (scanning electron microscope) and the smallest estimate (laser aerosol spectrometer).

  20. Size and concentration measurement of an industrial aerosol.

    PubMed

    O'Brien, D; Baron, P; Willeke, K

    1986-07-01

    Several real-time particle sizing instruments were evaluated for measuring the size distribution and concentration of the aerosol produced during the high speed grinding of gray iron castings. Aerosol was sampled in the airstream entrained by the motion of a spinning grinding wheel in a pilot grinding operation. Measurement methods based on differing physical principles were selected for evaluation and compared: particle inertia (aerodynamic particle sizer and quartz crystal microbalance cascade impactor); light scattering (laser aerosol spectrometer); and projected-area microscopy (scanning electron microscope). Inferences of aerodynamic diameter based on measurements by the laser aerosol spectrometer consistently undersized that determined by the aerodynamic particle sizer by a factor of 1.5. Estimates of aerodynamic diameters from projected area diameters determined by scanning electron microscopy differed from those obtained by the aerodynamic particle sizer by a factor of 2. Differences appeared to be a non-linear function of particle diameter. Estimates of respirable mass determined from mass-weighted particle size spectra varied by a factor of 6 between the largest estimate (scanning electron microscope) and the smallest estimate (laser aerosol spectrometer).

  1. Reconciling satellite aerosol optical thickness and surface fine particle mass through aerosol liquid water

    NASA Astrophysics Data System (ADS)

    Nguyen, Thien Khoi V.; Ghate, Virendra P.; Carlton, Annmarie G.

    2016-11-01

    Summertime aerosol optical thickness (AOT) over the southeast U.S. is sharply enhanced over wintertime values. This seasonal pattern is unique and of particular interest because temperatures there have not warmed over the past 100 years. Patterns in surface fine particle mass are inconsistent with satellite reported AOT. In this work, we attempt to reconcile the spatial and temporal distribution of AOT over the U.S. with particle mass measurements at the surface by examining trends in aerosol liquid water (ALW), a particle constituent that scatters radiation and affects satellite AOT but is removed in mass measurements at routine surface monitoring sites. We employ the thermodynamic model ISORROPIAv2.1 to estimate ALW mass concentrations at Interagency Monitoring of PROtected Visual Environments sites using measured ion mass concentrations and North American Regional Reanalysis meteorological data. Excellent agreement between Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations AOT and estimated ALW provides a plausible explanation for the discrepancies in the geographical patterns of AOT and aerosol mass measurements.

  2. Atmospheric pressure flow reactor / aerosol mass spectrometer studies of tropospheric aerosol nucleat and growth kinetics. Final report, June, 2001

    SciTech Connect

    Worsnop, Douglas R.

    2001-06-01

    The objective of this program was to determine the mechanisms and rates of growth and transformation and growth processes that control secondary aerosol particles in both the clear and polluted troposphere. The experimental plan coupled an aerosol mass spectrometer (AMS) with a chemical ionization mass spectrometer to provide simultaneous measurement of condensed and particle phases. The first task investigated the kinetics of tropospheric particle growth and transformation by measuring vapor accretion to particles (uptake coefficients, including mass accommodation coefficients and heterogeneous reaction rate coefficients). Other work initiated investigation of aerosol nucleation processes by monitoring the appearance of submicron particles with the AMS as a function of precursor gas concentrations. Three projects were investigated during the program: (1) Ozonolysis of oleic acid aerosols as model of chemical reactivity of secondary organic aerosol; (2) Activation of soot particles by measurement deliquescence in the presence of sulfuric acid and water vapor; (3) Controlled nucleation and growth of sulfuric acid aerosols.

  3. Aerosol detection efficiency in inductively coupled plasma mass spectrometry

    SciTech Connect

    Hubbard, Joshua A.; Zigmond, Joseph A.

    2016-03-02

    We used an electrostatic size classification technique to segregate particles of known composition prior to being injected into an inductively coupled plasma mass spectrometer (ICP-MS). Moreover, we counted size-segregated particles with a condensation nuclei counter as well as sampled with an ICP-MS. By injecting particles of known size, composition, and aerosol concentration into the ICP-MS, efficiencies of the order of magnitude aerosol detection were calculated, and the particle size dependencies for volatile and refractory species were quantified. Similar to laser ablation ICP-MS, aerosol detection efficiency was defined as the rate at which atoms were detected in the ICP-MS normalized by the rate at which atoms were injected in the form of particles. This method adds valuable insight into the development of technologies like laser ablation ICP-MS where aerosol particles (of relatively unknown size and gas concentration) are generated during ablation and then transported into the plasma of an ICP-MS. In this study, we characterized aerosol detection efficiencies of volatile species gold and silver along with refractory species aluminum oxide, cerium oxide, and yttrium oxide. Aerosols were generated with electrical mobility diameters ranging from 100 to 1000 nm. In general, it was observed that refractory species had lower aerosol detection efficiencies than volatile species, and there were strong dependencies on particle size and plasma torch residence time. Volatile species showed a distinct transition point at which aerosol detection efficiency began decreasing with increasing particle size. This critical diameter indicated the largest particle size for which complete particle detection should be expected and agreed with theories published in other works. Aerosol detection efficiencies also displayed power law dependencies on particle size. Aerosol detection efficiencies ranged from 10-5 to 10-11. Free molecular heat and mass transfer

  4. Aerosol detection efficiency in inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Hubbard, Joshua A.; Zigmond, Joseph A.

    2016-05-01

    An electrostatic size classification technique was used to segregate particles of known composition prior to being injected into an inductively coupled plasma mass spectrometer (ICP-MS). Size-segregated particles were counted with a condensation nuclei counter as well as sampled with an ICP-MS. By injecting particles of known size, composition, and aerosol concentration into the ICP-MS, efficiencies of the order of magnitude aerosol detection were calculated, and the particle size dependencies for volatile and refractory species were quantified. Similar to laser ablation ICP-MS, aerosol detection efficiency was defined as the rate at which atoms were detected in the ICP-MS normalized by the rate at which atoms were injected in the form of particles. This method adds valuable insight into the development of technologies like laser ablation ICP-MS where aerosol particles (of relatively unknown size and gas concentration) are generated during ablation and then transported into the plasma of an ICP-MS. In this study, we characterized aerosol detection efficiencies of volatile species gold and silver along with refractory species aluminum oxide, cerium oxide, and yttrium oxide. Aerosols were generated with electrical mobility diameters ranging from 100 to 1000 nm. In general, it was observed that refractory species had lower aerosol detection efficiencies than volatile species, and there were strong dependencies on particle size and plasma torch residence time. Volatile species showed a distinct transition point at which aerosol detection efficiency began decreasing with increasing particle size. This critical diameter indicated the largest particle size for which complete particle detection should be expected and agreed with theories published in other works. Aerosol detection efficiencies also displayed power law dependencies on particle size. Aerosol detection efficiencies ranged from 10- 5 to 10- 11. Free molecular heat and mass transfer theory was applied, but

  5. Aerosol detection efficiency in inductively coupled plasma mass spectrometry

    DOE PAGES

    Hubbard, Joshua A.; Zigmond, Joseph A.

    2016-03-02

    We used an electrostatic size classification technique to segregate particles of known composition prior to being injected into an inductively coupled plasma mass spectrometer (ICP-MS). Moreover, we counted size-segregated particles with a condensation nuclei counter as well as sampled with an ICP-MS. By injecting particles of known size, composition, and aerosol concentration into the ICP-MS, efficiencies of the order of magnitude aerosol detection were calculated, and the particle size dependencies for volatile and refractory species were quantified. Similar to laser ablation ICP-MS, aerosol detection efficiency was defined as the rate at which atoms were detected in the ICP-MS normalized bymore » the rate at which atoms were injected in the form of particles. This method adds valuable insight into the development of technologies like laser ablation ICP-MS where aerosol particles (of relatively unknown size and gas concentration) are generated during ablation and then transported into the plasma of an ICP-MS. In this study, we characterized aerosol detection efficiencies of volatile species gold and silver along with refractory species aluminum oxide, cerium oxide, and yttrium oxide. Aerosols were generated with electrical mobility diameters ranging from 100 to 1000 nm. In general, it was observed that refractory species had lower aerosol detection efficiencies than volatile species, and there were strong dependencies on particle size and plasma torch residence time. Volatile species showed a distinct transition point at which aerosol detection efficiency began decreasing with increasing particle size. This critical diameter indicated the largest particle size for which complete particle detection should be expected and agreed with theories published in other works. Aerosol detection efficiencies also displayed power law dependencies on particle size. Aerosol detection efficiencies ranged from 10-5 to 10-11. Free molecular heat and mass transfer theory was

  6. Systematic aerosol characterization by combining GOME-2 UV Aerosol Indices with trace gas concentrations

    NASA Astrophysics Data System (ADS)

    Penning de Vries, M.; Stammes, P.; Wagner, T.

    2012-04-01

    The task of determining aerosol type using passive remote sensing instruments is a daunting one. First, because the variety in aerosol (optical) properties is very large; and second, because the effect of aerosols on the detected top-of-atmosphere reflectance spectrum is smooth and mostly featureless. In addition, spectrometers like GOME-2 have a coarse spatial resolution, which makes aerosol characterization even more difficult due to interferences with clouds. On account of these problems, we do not attempt to derive aerosol properties from single measurements: instead, we combine time series of UV Aerosol Index and trace gas concentrations to derive the dominating aerosol type for each season. Aside from the Index values and trace gas concentrations themselves, the correlation between UV Aerosol Indices (which are indicative of aerosol absorption) with NO2, HCHO, and CHOCHO columns - or absence of it - provides clues to the (main) source of the aerosols in the investigated region and time range. For example: a high correlation of HCHO and Absorbing Aerosol Index points to aerosols from biomass burning, highly correlated CHOCHO, HCHO, and SCattering Index indicate biogenic secondary organic aerosols, and coinciding high NO2 concentrations with high SCattering Index values are associated with industrial and urban aerosols. We here present case studies for several regions to demonstrate the suitability of our approach. Then, we introduce a method to systematically derive the dominating aerosol type on a global scale on time scales varying from monthly to yearly.

  7. Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3− aerosol during the 2013 Southern Oxidant and Aerosol Study

    DOE PAGES

    Allen, H. M.; Draper, D. C.; Ayres, B. R.; ...

    2015-09-25

    Inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two periods of high aerosol nitrate (NO3−) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of supermicron crustal and sea spray aerosol species, particularly Na+ and Ca2+, and with a shift towards aerosol with larger (1 to 2.5 μm) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO3more » and particles, reactions that are facilitated by transport of crustal dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH4NO3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. In addition, calculation of the rate of the heterogeneous uptake of HNO3 on mineral aerosol supports the conclusion that aerosol NO3− is produced primarily by this process, and is likely limited by the availability of mineral cation-containing aerosol surface area. Modeling of NO3− and HNO3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas–aerosol phase partitioning.« less

  8. Secondary Ion Mass Spectrometry of Environmental Aerosols

    SciTech Connect

    Gaspar, Daniel J.; Cliff, John B.

    2010-08-01

    Atmospheric particles influence many aspects of climate, air quality and human health. Understanding the composition, chemistry and behavior of atmospheric aerosols is a key remaining challenge in improving climate models. Furthermore, particles may be traced back to a particular source based on composition, stable isotope ratios, or the presence of particular surface chemistries. Finally, the characterization of atmospheric particles in the workplace plays an important role in understanding the potential for exposure and environmental and human health effects to engineered and natural nanoscale particles. Secondary ion mass spectrometry (SIMS) is a useful tool in determining any of several aspects of the structure, composition and chemistry of these particles. Often used in conjunction with other surface analysis and electron microscopy methods, SIMS has been used to determine or confirm reactions on and in particles, the presence of particular organic species on the surface of atmospheric aerosols and several other interesting and relevant findings. Various versions of SIMS instruments – dynamic SIMS, time of flight secondary ion mass spectrometry or TOF-SIMS, nanoSIMS – have been used to determine specific aspects of aerosol structure and chemistry. This article describes the strengths of each type of SIMS instrument in the characterization of aerosols, along with guidance on sample preparation, specific characterization specific to the particular information sought in the analysis. Examples and guidance are given for each type of SIMS analysis.

  9. Background aerosol over the Himalayas and Tibetan Plateau: observed characteristics of aerosol mass loading

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Cong, Zhiyuan; Wang, Yuesi; Xin, Jinyuan; Wan, Xin; Pan, Yuepeng; Liu, Zirui; Wang, Yonghong; Zhang, Guoshuai; Wang, Zhongyan; Wang, Yongjie; Kang, Shichang

    2017-01-01

    To investigate the atmospheric aerosols of the Himalayas and Tibetan Plateau (HTP), an observation network was established within the region's various ecosystems, including at the Ngari, Qomolangma (QOMS), Nam Co, and Southeastern Tibetan (SET) stations. In this paper we illustrate aerosol mass loadings by integrating in situ measurements with satellite and ground-based remote sensing datasets for the 2011-2013 period, on both local and large scales. Mass concentrations of these surface atmospheric aerosols were relatively low and varied with land cover, showing a general tendency of Ngari and QOMS (barren sites) > Nam Co (grassland site) > SET (forest site). Daily averages of online PM2.5 (particulates with aerodynamic diameters below 2.5 µm) at these sites were sequentially 18.2 ± 8.9, 14.5 ± 7.4, 11.9 ± 4.9 and 11.7 ± 4.7 µg m-3. Correspondingly, the ratios of PM2.5 to total suspended particles (TSP) were 27.4 ± 6.65, 22.3 ± 10.9, 37.3 ± 11.1 and 54.4 ± 6.72 %. Bimodal mass distributions of size-segregated particles were found at all sites, with a relatively small peak in accumulation mode and a more notable peak in coarse mode. Diurnal variations in fine-aerosol masses generally displayed a bi-peak pattern at the QOMS, Nam Co and SET stations and a single-peak pattern at the Ngari station, controlled by the effects of local geomorphology, mountain-valley breeze circulation and aerosol emissions. Dust aerosol content in PM2.1 samples gave fractions of 26 % at the Ngari station and 29 % at the QOMS station, or ˜ 2-3 times that of reported results at human-influenced sites. Furthermore, observed evidence confirmed the existence of the aerodynamic conditions necessary for the uplift of fine particles from a barren land surface. Combining surface aerosol data and atmospheric-column aerosol optical properties, the TSP mass and aerosol optical depth (AOD) of the Multi-angle Imaging Spectroradiometer (MISR) generally decreased as land cover changed from

  10. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea-ice

    NASA Astrophysics Data System (ADS)

    Humphries, R. S.; Klekociuk, A. R.; Schofield, R.; Keywood, M.; Ward, J.; Wilson, S. R.

    2015-10-01

    The effect of aerosols on clouds and their radiative properties is one of the largest uncertainties in our understanding of radiative forcing. A recent study has concluded that better characterisation of pristine, natural aerosol processes leads to the largest reduction in these uncertainties. Antarctica, being far from anthropogenic activities, is an ideal location for the study of natural aerosol processes. Aerosol measurements in Antarctica are often limited to boundary layer air-masses at spatially sparse coastal and continental research stations, with only a handful of studies in the sea ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the ice-breaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3) concentrations exhibited a five-fold increase moving across the Polar Front, with mean Polar Cell concentrations of 1130 cm-3 - higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air-masses quickly from the free-troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea ice boundary layer air-masses travelled equator-ward into the low albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei where, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and

  11. Organic Aerosols in Rural and Remote Atmospheric Environments: Insights from Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Jimenez, J.; Ulbrich, I.; Dunlea, E.; Decarlo, P.; Huffman, A.; Allan, J.; Coe, H.; Alfarra, R.; Canagaratna, M.; Onasch, T.; Jayne, J.; Worsnop, D.; Takami, A.; Miyoshi, T.; Shimono, A.; Hatakeyama, S.; Weimer, S.; Demerjian, K.; Drewnick, F.; Schneider, J.; Middlebrook, A.; Bahreini, R.; Cotrell, L.; Griffin, R.; Leaitch, R.; Li, S.; Hayden, K.; Rautiainen, J.

    2006-12-01

    Organic matter usually accounts for a large fraction of the fine particle mass in rural and remote atmospheres. However, little is known about the sources and properties of this material. Here we report findings on the characteristics and the major types of organic aerosols (OA) in urban downwind, high elevation, forested, and marine atmospheres based on analyses of more than 20 highly time resolved AMS datasets sampled from various locations in the mid-latitude Northern Hemisphere. Organic aerosol components are extracted from these datasets using a custom multiple component mass spectral analysis technique and the Positive Matrix Factorization (PMF) method. These components are evaluated according to their extracted mass spectra and correlations to aerosol species, such as sulfate, nitrate, and elemental carbon, and gas-phase tracer compounds, such as CO and NOx. We have identified a hydrocarbon-like organic aerosol (HOA) component similar in mass spectra to the hydrocarbon substances observed at urban locations. We have also identified several oxygenated OA (OOA) components that show different fragmentation patterns and oxygen to carbon ratios in their mass spectra. Two OOA components a highly oxygenated that has mass spectrum resembling that of fulvic acid (a model compound representative for highly processed/oxidized organics in the environment) and a less oxygenated OOA component, whose spectrum is dominated with ions that are mainly associated with carbonyls and alcohols, are very frequently observed at various rural/remote sites. The oxygenated OOA component is more prevalent at downwind sites influenced by urban transport and the less oxygenated shows correlation to biogenic chamber OA at some locations. Compared to the total OOA concentration, HOA is generally very small and accounts for < 10% of the total OA mass at rural/remote sites. The comparisons between the concentrations of HOA and primary OA (POA) that would be predicted according to inert

  12. ACTRIS ACSM intercomparison - Part I: Reproducibility of concentration and fragment results from 13 individual Quadrupole Aerosol Chemical Speciation Monitors (Q-ACSM) and consistency with Time-of-Flight ACSM (ToF-ACSM), High Resolution ToF Aerosol Mass Spectrometer (HR-ToF-AMS) and other co-located instruments

    NASA Astrophysics Data System (ADS)

    Crenn, V.; Sciare, J.; Croteau, P. L.; Verlhac, S.; Fröhlich, R.; Belis, C. A.; Aas, W.; Äijälä, M.; Alastuey, A.; Artiñano, B.; Baisnée, D.; Bonnaire, N.; Bressi, M.; Canagaratna, M.; Canonaco, F.; Carbone, C.; Cavalli, F.; Coz, E.; Cubison, M. J.; Esser-Gietl, J. K.; Green, D. C.; Gros, V.; Heikkinen, L.; Herrmann, H.; Lunder, C.; Minguillón, M. C.; Močnik, G.; O'Dowd, C. D.; Ovadnevaite, J.; Petit, J.-E.; Petralia, E.; Poulain, L.; Priestman, M.; Riffault, V.; Ripoll, A.; Sarda-Estève, R.; Slowik, J. G.; Setyan, A.; Wiedensohler, A.; Baltensperger, U.; Prévôt, A. S. H.; Jayne, J. T.; Favez, O.

    2015-07-01

    As part of the European ACTRIS project, the first large Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) intercomparison study was conducted in the region of Paris for three weeks during the late fall-early winter period (November-December 2013). The first week was dedicated to tuning and calibration of each instrument whereas the second and third were dedicated to side-by-side comparison in ambient conditions with co-located instruments providing independent information on submicron aerosol optical, physical and chemical properties. Near real-time measurements of the major chemical species (organic matter, sulfate, nitrate, ammonium and chloride) in the non-refractory submicron aerosols (NR-PM1) were obtained here from 13 Q-ACSM. The results show that these instruments can produce highly comparable and robust measurements of the NR-PM1 total mass and its major components. Taking the median of the 13 Q-ACSM as a reference for this study, strong correlations (r2 > 0.9) were observed systematically for each individual ACSM across all chemical families except for chloride for which three ACSMs showing weak correlations partly due to the very low concentrations during the study. Reproducibility expanded uncertainties of Q-ACSM concentration measurements were determined using appropriate methodologies defined by the International Standard Organization (ISO 17025) and were found to be of 9, 15, 19, 28 and 36 % for NR-PM1, nitrate, organic matter, sulfate and ammonium respectively. However, discrepancies were observed in the relative concentrations of the constituent mass fragments for each chemical component. In particular, significant differences were observed for the organic fragment at mass-to-charge ratio 44, which is a key parameter describing the oxidation state of organic aerosol. Following this first major intercomparison exercise of a large number of ACSMs, detailed intercomparison results are presented as well as a discussion of some recommendations

  13. Effects of aerosol organics on cloud condensation nucleus (CCN) concentration and first indirect aerosol effect

    SciTech Connect

    Wang, J. X.; Lee, Y.- N.; Daum, Peter H.; Jayne, John T.; Alexander, M. L.

    2008-11-03

    Abstract. Aerosol microphysics, chemical composition, and CCN properties were measured on the Department of Energy Gulfstream-1 aircraft during the Marine Stratus/ Stratocumulus Experiment (MASE) conducted over the coastal waters between Point Reyes National Seashore and Monterey Bay, California, in July 2005. Aerosols measured during MASE included free tropospheric aerosols, marine boundary layer aerosols, and aerosols with high organic concentration within a thin layer above the cloud. Closure analysis was carried out for all three types of aerosols by comparing the measured CCN concentrations at 0.2% supersaturation to those predicted based on size distribution and chemical composition using K¨ohler theory. The effect of aerosol organic species on predicted CCN concentration was examined using a single hygroscopicity parameterization.

  14. Influence of local and regional sources on the observed spatial and temporal variability of size resolved atmospheric aerosol mass concentrations and water-soluble species in the Athens metropolitan area

    NASA Astrophysics Data System (ADS)

    Eleftheriadis, Konstantinos; Ochsenkuhn, Klaus M.; Lymperopoulou, Theopisti; Karanasiou, Angeliki; Razos, Panayiotis; Ochsenkuhn-Petropoulou, Maria

    2014-11-01

    The variability of common aerosol species in large Metropolitan urban areas is a major air quality issue with strong health impacts of large populations. PM10 and PM2.5 particulate matter samples were obtained at three sites characteristic of industrial, urban traffic and sub-urban residential areas in the Athens basin. Samples were analysed for anions (Cl-, NO3-, SO42-) and cations (K+, Na+, Ca2+, Mg2+, NH4+) using ion chromatography. The spatial and temporal variability for the particulate matter (PM) concentration mass and water-soluble ionic species concentrations for the investigated sites were studied. Mean PM fine concentration levels were 20% higher at the industrial and the central urban areas compared to those in the suburban area (24.2 μg/m3). The mean values for the coarse fraction at those two sites were two to three times higher compared to those at the suburban site (12.4 μg/m3). Comparable concentration levels of most species were observed in all areas, while SO42- and NO3- differ at a significant level. Furthermore, the average size distributions of the mass and individual ions at the suburban site (NCSR Demokritos) showed a bimodal size distribution. SO42- and NH4+ have their main peak in the fine fraction while NO3- showed equal distribution on the fine and coarse mode.. Good correlation was found for SO42- and NO3- with Ca2+ and Na+ with Cl- for the coarse fraction in the industrial area. NH4+ was closely correlated with SO42- in the fine particles and in all areas. For the urban site the best correlations in coarse particulates were reported between Na+/Mg2+-Cl-, Ca2+/Mg2+-SO42-, explained by neutralization of acidic aerosol by soil dust and sea salt in the coarse fraction. Moreover, time weighted concentrations roses at the industrial and urban sites, showed no significant directional dependence, indicating either uniform generation of mainly the coarse species within the metropolitan area or major influence of the regional background for

  15. Reactions and mass spectra of complex particles using Aerosol CIMS

    NASA Astrophysics Data System (ADS)

    Hearn, John D.; Smith, Geoffrey D.

    2006-12-01

    Aerosol chemical ionization mass spectrometry (CIMS) is used both on- and off-line for the analysis of complex laboratory-generated and ambient particles. One of the primary advantages of Aerosol CIMS is the low degree of ion fragmentation, making this technique well suited for investigating the reactivity of complex particles. To demonstrate the usefulness of this "soft" ionization, particles generated from meat cooking were reacted with ozone and the composition was monitored as a function of reaction time. Two distinct kinetic regimes were observed with most of the oleic acid in these particles reacting quickly but with 30% appearing to be trapped in the complex mixture. Additionally, detection limits are measured to be sufficiently low (100-200 ng/m3) to detect some of the more abundant constituents in ambient particles, including sulfate, which is measured in real-time at 1.2 [mu]g/m3. To better characterize complex aerosols from a variety of sources, a novel off-line collection method was also developed in which non-volatile and semi-volatile organics are desorbed from particles and concentrated in a cold U-tube. Desorption from the U-tube followed by analysis with Aerosol CIMS revealed significant amounts of nicotine in cigarette smoke and levoglucosan in oak and pine smoke, suggesting that this may be a useful technique for monitoring particle tracer species. Additionally, secondary organic aerosol formed from the reaction of ozone with R-limonene and volatile organics from orange peel were analyzed off-line showing large molecular weight products (m/z > 300 amu) that may indicate the formation of oligomers. Finally, mass spectra of ambient aerosol collected offline reveal a complex mixture of what appears to be highly processed organics, some of which may contain nitrogen.

  16. Mass size distributions of elemental aerosols in industrial area.

    PubMed

    Moustafa, Mona; Mohamed, Amer; Ahmed, Abdel-Rahman; Nazmy, Hyam

    2015-11-01

    Outdoor aerosol particles were characterized in industrial area of Samalut city (El-minia/Egypt) using low pressure Berner cascade impactor as an aerosol sampler. The impactor operates at 1.7 m(3)/h flow rate. Seven elements were investigated including Ca, Ba, Fe, K, Cu, Mn and Pb using atomic absorption technique. The mean mass concentrations of the elements ranged from 0.42 ng/m(3) (for Ba) to 89.62 ng/m(3) (for Fe). The mass size distributions of the investigated elements were bi-modal log normal distribution corresponding to the accumulation and coarse modes. The enrichment factors of elements indicate that Ca, Ba, Fe, K, Cu and Mn are mainly emitted into the atmosphere from soil sources while Pb is mostly due to anthropogenic sources.

  17. Derivation of Aerosol Columnar Mass from MODIS Optical Depth

    NASA Technical Reports Server (NTRS)

    Gasso, Santiago; Hegg, Dean A.

    2003-01-01

    In order to verify performance, aerosol transport models (ATM) compare aerosol columnar mass (ACM) with those derived from satellite measurements. The comparison is inherently indirect since satellites derive optical depths and they use a proportionality constant to derive the ACM. Analogously, ATMs output a four dimensional ACM distribution and the optical depth is linearly derived. In both cases, the proportionality constant requires a direct intervention of the user by prescribing the aerosol composition and size distribution. This study introduces a method that minimizes the direct user intervention by making use of the new aerosol products of MODIS. A parameterization is introduced for the derivation of columnar aerosol mass (AMC) and CCN concentration (CCNC) and comparisons between sunphotometer, MODIS Airborne Simulator (MAS) and in-measurements are shown. The method still relies on the scaling between AMC and optical depth but the proportionality constant is dependent on the MODIS derived r$_{eff}$,\\eta (contribution of the accumulation mode radiance to the total radiance), ambient RH and an assumed constant aerosol composition. The CCNC is derived fkom a recent parameterization of CCNC as a function of the retrieved aerosol volume. By comparing with in-situ data (ACE-2 and TARFOX campaigns), it is shown that retrievals in dry ambient conditions (dust) are improved when using a proportionality constant dependent on r$ {eff}$ and \\eta derived in the same pixel. In high humidity environments, the improvement inthe new method is inconclusive because of the difficulty in accounting for the uneven vertical distribution of relative humidity. Additionally, two detailed comparisons of AMC and CCNC retrieved by the MAS algorithm and the new method are shown. The new method and MAS retrievals of AMC are within the same order of magnitude with respect to the in-situ measurements of aerosol mass. However, the proposed method is closer to the in-situ measurements than

  18. Investigating types and sources of organic aerosol in Rocky Mountain National Park using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schurman, M. I.; Lee, T.; Sun, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L., Jr.

    2015-01-01

    The environmental impacts of atmospheric particles are highlighted in remote areas where visibility and ecosystem health can be degraded by even relatively low particle concentrations. Submicron particle size, composition, and source apportionment were explored at Rocky Mountain National Park using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer. This summer campaign found low average, but variable, particulate mass (PM) concentrations (max = 93.1 μg m-3, avg. = 5.13 ± 2.72 μg m-3) of which 75.2 ± 11.1% is organic. Low-volatility oxidized organic aerosol (LV-OOA, 39.3% of PM1 on average) identified using Positive Matrix Factorization appears to be mixed with ammonium sulfate (3.9% and 16.6% of mass, respectively), while semi-volatile OOA (27.6%) is correlated with ammonium nitrate (nitrate: 4.3%); concentrations of these mixtures are enhanced with upslope (SE) surface winds from the densely populated Front Range area, indicating the importance of transport. A local biomass burning organic aerosol (BBOA, 8.4%) source is suggested by mass spectral cellulose combustion markers (m/z 60 and 73) limited to brief, high-concentration, polydisperse events (suggesting fresh combustion), a diurnal maximum at 22:00 local standard time when campfires were set at adjacent summer camps, and association with surface winds consistent with local campfire locations. The particle characteristics determined here represent typical summertime conditions at the Rocky Mountain site based on comparison to ~10 years of meteorological, particle composition, and fire data.

  19. Investigating types and sources of organic aerosol in Rocky Mountain National Park using aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schurman, M. I.; Lee, T.; Sun, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L., Jr.

    2014-07-01

    The environmental impacts of atmospheric particles are highlighted in remote areas where visibility and ecosystem health can be degraded by even relatively low particle concentrations. Submicron particle size, composition, and source apportionment were explored at Rocky Mountain National Park using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer. This summer campaign found low average, but variable, particulate mass (PM) concentrations (max = 93.1 μg m-3, avg. = 5.13 ± 2.72 μg m-3) of which 75.2 ± 11.1% is organic. Low-volatility oxidized organic aerosol (LV-OOA, 39.3% of PM1 on average) identified using Positive Matrix Factorization appears to be mixed with ammonium sulfate (3.9 and 16.6% of mass, respectively), while semi-volatile OOA (27.6%) is correlated with ammonium nitrate (nitrate: 4.3%); concentrations of these mixtures are enhanced with upslope (SE) surface winds from the densely populated Front Range area, indicating the importance of transport. A local biomass burning organic aerosol (BBOA, 8.4%) source is suggested by mass spectral cellulose combustion markers (m/zs 60 and 73) limited to brief, high-concentration, polydisperse events (suggesting fresh combustion), a diurnal maximum at 22:00 local standard time (LST) when campfires were set at adjacent summer camps, and association with surface winds consistent with local campfire locations. The particle characteristics determined here represent typical summertime conditions at the Rocky Mountain site based on comparison to ∼10 years of meteorological, particle composition, and fire data.

  20. The effect of aerosol vertical profiles on satellite-estimated surface particle sulfate concentrations

    SciTech Connect

    Liu, Yang; Wang, Zifeng; Wang, Jun; Ferrare, Richard A.; Newsom, Rob K.; Welton, Ellsworth J.

    2011-02-15

    The aerosol vertical distribution is an important factor in determining the relationship between satellite retrieved aerosol optical depth (AOD) and ground-level fine particle pollution concentrations. We evaluate how aerosol profiles measured by ground-based lidar and simulated by models can help improve the association between AOD retrieved by the Multi-angle Imaging Spectroradiometer (MISR) and fine particle sulfate (SO4) concentrations using matched data at two lidar sites. At the Goddard Space Flight Center (GSFC) site, both lidar and model aerosol profiles marginally improve the association between SO4 concentrations and MISR fractional AODs, as the correlation coefficient between cross-validation (CV) and observed SO4 concentrations changes from 0.87 for the no-scaling model to 0.88 for models scaled with aerosol vertical profiles. At the GSFC site, a large amount of urban aerosols resides in the well-mixed boundary layer so the column fractional AODs are already excellent indicators of ground-level particle pollution. In contrast, at the Atmospheric Radiation Measurement Program (ARM) site with relatively low aerosol loadings, scaling substantially improves model performance. The correlation coefficient between CV and observed SO4 concentrations is increased from 0.58 for the no-scaling model to 0.76 in the GEOS-Chem scaling model, and the model bias is reduced from 17% to 9%. In summary, despite the inaccuracy due to the coarse horizontal resolution and the challenges of simulating turbulent mixing in the boundary layer, GEOS-Chem simulated aerosol profiles can still improve methods for estimating surface aerosol (SO4) mass from satellite-based AODs, particularly in rural areas where aerosols in the free troposphere and any long-range transport of aerosols can significantly contribute to the column AOD.

  1. Organic Mass Fragments and Organic Functional Groups in Aged Biomass Burning and Fossil Fuel Combustion Aerosol

    NASA Astrophysics Data System (ADS)

    Day, D. A.; Hawkins, L. N.; Russell, L. M.

    2009-12-01

    Organic functional group concentrations in submicron aerosol particles collected from 27 June to 17 September at the Scripps Pier in La Jolla, California as part of AeroSCOPE 2008 were quantified using Fourier Transform Infrared (FTIR) spectroscopy. Organic and inorganic non-refractory components in the same air masses were quantified using a Quadrupole Aerosol Mass Spectrometer (Q-AMS). Previous measurements at the Scripps pier indicate that a large fraction of submicron particle mass originates in Los Angeles and the port of Long Beach. Additional particle sources to the region include local urban emissions and periodic biomass burning during large wildfires. Three distinct types of organic aerosol components were identified from organic composition and elemental tracers, including biomass burning, fossil fuel combustion, and polluted marine components. Fossil fuel combustion organic aerosol was dominated by unsaturated alkane and was correlated with sulfur, vanadium, and nickel supporting ship and large trucks in and around the Los Angeles/Long Beach region as the dominant source. Biomass burning organic aerosol comprised a smaller unsaturated alkane fraction and larger fractions of non-acid carbonyl, amine, and carboxylic acid and was correlated with potassium and bromine. Polluted marine organic aerosol was dominated by organic hydroxyl and unsaturated alkane and was not correlated with any elemental tracers. Mass spectra of the organic aerosol support the aerosol sources determined by organic functional groups and elemental tracers and contain fragments commonly attributed to oxygenated organic aerosol (OOA), hydrocarbon-like organic aerosol (HOA), and biomass burning organic aerosol (BBOA). Comparisons of the PMF-derived Q-AMS source spectra with FTIR source spectra and functional group composition provide additional information on the relationship between commonly reported organic aerosol factors and organic functional groups in specific organic aerosol

  2. Aerosol Composition in the Los Angeles Basin Studied by High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Hayes, P. L.; Ortega, A. M.; Cubison, M.; Hu, W.; Toohey, D. W.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Alvarez, S. L.; Rappenglueck, B.; Allan, J. D.; Taylor, J.; Holloway, J. S.; Gilman, J. B.; Kuster, W. C.; De Gouw, J. A.; Massoli, P.; Zhang, X.; Weber, R.; Zhao, Y.; Cliff, S. S.; Wexler, A. S.; Isaacman, G. A.; Worton, D. R.; Kreisberg, N. M.; Hering, S. V.; Goldstein, A. H.; Jimenez, J. L.

    2011-12-01

    Atmospheric aerosols impact climate and health, but their sources and composition are poorly understood. To address this knowledge gap, a high-resolution aerosol mass spectrometer (AMS) and complementary instrumentation were deployed during the 2010 CalNex campaign to characterize aerosol composition in the Los Angeles (LA) area. Total mass concentrations as well as the species concentrations measured by the AMS compare well with most other instruments. Nitrate dominates in the mornings, but its concentration is reduced in the afternoon when organic aerosols (OA) increase and dominate. The diurnal variations in concentrations are strongly influenced by emission transport from the source-rich western basin. The average OA to enhanced CO ratio increases with photochemical age from 25 to 80 μg m-3 ppm-1, which indicates significant secondary OA (SOA) production and that a large majority of OA is secondary in aged air. The ratio values are similar to those from Mexico City as well as New England and the Mid-Atlantic States. Positive matrix factorization (PMF) is used to assess the concentrations of different OA components. The major OA classes are oxygenated OA (OOA, a surrogate for total SOA), and hydrocarbon-like OA (HOA, a surrogate for primary combustion OA). Several subclasses of OA are identified as well including diesel-influenced HOA (DI-HOA) and non-diesel HOA. DI-HOA exhibits low concentrations on Sundays consistent with the well-known weekday/weekend effect in LA. PMF analysis finds that OOA is 67% of the total OA concentration. A strong correlation between OOA and Ox (O3 + NO2) concentrations is observed with a slope of 0.15 that suggests the production of fresh SOA in Pasadena. Plotting the OA elemental ratios in a Van Krevelen diagram (H:C vs. O:C) yields a slope of -0.6, which is less steep than that observed in Riverside during the SOAR-2005 campaign. The difference in slopes may be attributed to the highly oxidized HOA present in Pasadena that is

  3. Process evaluation of sea salt aerosol concentrations at remote marine locations

    NASA Astrophysics Data System (ADS)

    Struthers, H.; Ekman, A. M.; Nilsson, E. D.

    2011-12-01

    Sea salt, an important natural aerosol, is generated by bubbles bursting at the surface of the ocean. Sea salt aerosol contributes significantly to the global aerosol burden and radiative budget and are a significant source of cloud condensation nuclei in remote marine areas (Monahan et al., 1986). Consequently, changes in marine aerosol abundance is expected to impact on climate forcing. Estimates of the atmospheric burden of sea salt aerosol mass derived from chemical transport and global climate models vary greatly both in the global total and the spatial distribution (Texor et al. 2006). This large uncertainty in the sea salt aerosol distribution in turn contributes to the large uncertainty in the current estimates of anthropogenic aerosol climate forcing (IPCC, 2007). To correctly attribute anthropogenic climate change and to veraciously project future climate, natural aerosols including sea salt must be understood and accurately modelled. In addition, the physical processes that determine the sea salt aerosol concentration are susceptible to modification due to climate change (Carslaw et al., 2010) which means there is the potential for feedbacks within the climate/aerosol system. Given the large uncertainties in sea salt aerosol modelling, there is an urgent need to evaluate the process description of sea salt aerosols in global models. An extremely valuable source of data for model evaluation is the long term measurements of PM10 sea salt aerosol mass available from a number of remote marine observation sites around the globe (including the GAW network). Sea salt aerosol concentrations at remote marine locations depend strongly on the surface exchange (emission and deposition) as well as entrainment or detrainment to the free troposphere. This suggests that the key parameters to consider in any analysis include the sea surface water temperature, wind speed, precipitation rate and the atmospheric stability. In this study, the sea salt aerosol observations

  4. Aerosol Composition in Los Angeles During the 2010 CalNex Campaign Studied by High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Hayes, P. L.; Ortega, A. M.; Cubison, M.; Hu, W.; Toohey, D. W.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Alvarez, S.; Rappenglueck, B.; Allan, J. D.; McKeen, S. A.; Holloway, J. S.; Gilman, J. B.; Kuster, W. C.; Graus, M.; Warneke, C.; de Gouw, J. A.; Richter, R.; Hofer, J.; Prevot, A. S.; Jimenez, J. L.

    2010-12-01

    Submicron atmospheric aerosols impact climate and human health, but their sources and composition are poorly understood. To address this knowledge gap, high-resolution time-of-flight aerosol mass spectrometry (AMS) [DeCarlo et al. Anal. Chem. 2006] and other advanced instrumentation were deployed during the CalNex field campaign in May and June 2010 for 4 weeks to characterize the composition of aerosols in the Los Angeles area. Utilizing AMS, the concentrations for both organic and non-refractory inorganic (sulfate, nitrate, ammonium, chloride) submicron aerosols were quantified at the Caltech/Pasadena ground site 15 km NE of downtown Los Angeles. The total submicron mass concentration as well as the species concentrations measured by AMS compare well with other instruments. Nitrate aerosols appear to dominate in the cooler mornings, but their concentration is reduced in the afternoon when organic aerosols (OA) increase and dominate. The diurnal variations in concentration are strongly influenced by vertical dilution from the rising planetary boundary layer in the afternoon. Secondary organic aerosols (SOA) are an important fraction of submicron aerosols. To assess the concentrations of different OA components present at the site, positive matrix factorization (PMF) is used to analyze the field data. The major OA classes are oxygenated OA (OOA, a surrogate for total SOA), and hydrocarbon-like OA (HOA, a surrogate for primary combustion OA). Preliminary PMF analysis finds that OOA is consistently the largest type of OA present (~75% of the total OA concentration). This result suggests that the air mass over the site has undergone substantial chemical aging. The correlations between OOA and Ox (O3 + NO2) concentrations, as well as between HOA, CO and black carbon concentrations are strong and consistent with previous studies. AMS and 14C measurements are combined to determine the fractions of HOA and OOA from non-fossil vs. fossil sources. Using measurements of SOA

  5. On the contribution of organics to the North East Atlantic aerosol number concentration

    NASA Astrophysics Data System (ADS)

    Bialek, Jakub; Dall'Osto, Manuel; Monahan, Ciaran; Beddows, David; O'Dowd, Colin

    2012-12-01

    k-means statistical-cluster analysis of submicron aerosol size distributions is combined with coincident humidity tandem differential mobility analyser data, leading to five unique aerosol categories for hygroscopic growth factors (HGFs): low sea-salt background marine, high sea-salt background marine, coastal nucleation, open ocean nucleation and anthropogenically influenced scenarios. When considering only marine conditions, and generic aerosol species associated with this environment (e.g. non-sea-salt sulfate, sea-salt, partly soluble organic matter and water insoluble organic matter), the two-year annual average contribution to aerosol number concentration from the different generic species was made up as follows: 46% (30-54%) of partially modified ammonium sulfate particles; 23% (11-40%) of partially modified sea-salt; and the remaining 31% (25-35%) contribution attributed to two distinct organic species as evidenced by different, but low, HGFs. The analysis reveals that on annual timescales, ˜30% of the submicron marine aerosol number concentration is sourced from predominantly organic aerosol while 60% of the anthropogenic aerosol number is predominantly organic. Coastal nucleation events show the highest contribution of the lowest HGF mode (1.19), although this contribution is more likely to be influenced by inorganic iodine oxides. While organic mass internally mixed with inorganic salts will lower the activation potential of these mixed aerosol types, thereby potentially reducing the concentration of cloud condensation nuclei (CCN), pure organic water soluble particles are still likely to be activated into cloud droplets, thereby increasing the concentration of CCN. A combination of dynamics and aerosol concentrations will determine which effect will prevail under given conditions.

  6. Concentration, sources, and degradation of organic aerosol at Summit, Greenland

    NASA Astrophysics Data System (ADS)

    von Schneidemesser, Erika

    Characterization and understanding of the carbonaceous portion of the aerosol in the Arctic is limited. The objective of the research presented in this thesis was to improve the scope of knowledge pertaining to carbonaceous aerosols, in terms of atmospheric and snow concentrations, sources, and post-depositional processing. An extraction technique was developed to quantitatively identify a suite of organic compounds, typically observed in aerosol samples, at trace level concentrations in snow melt water samples. A field campaign of sampling and exposure experiments was carried out at Summit, Greenland. A 3-meter snow pit, sampled at 20 cm intervals, was analyzed for organic compounds and total organic carbon (TOC). The average concentration of TOC for the entire pit was 64 mug C kg-1. The quantified organic compounds comprised 6 to 24% of TOC throughout the layers. Median concentrations of the water insoluble individual organic compounds ranged from 0.14 ng kg-1 (hopane) to 2200 ng kg-1 (alkanoic acid) at any one depth. High-volume aerosol samples were collected over a six month period and analyzed for organics. Median concentrations ranged from 0.00045 ng kg-1 (hopane) to 0.23 ng kg-1 (levoglucosan) in the air samples. Source apportionment results from the aerosol samples indicate anthropogenic influence at Summit from biomass burning, fossil fuels, and vegetative detritus. The majority (>90%) of the organic carbon in the aerosol was estimated to be secondary organic aerosol. To investigate the post-depositional processing of organic compounds in snow, contaminant labeled snow was produced and exposed for up to 72 hours on the surface of the Greenland ice sheet at Summit. Degradation of alkanes, acids, and PAHs to a threshold concentration was observed. The threshold concentration, at which no further degradation was observed, ranged from 10 to 60% of the original (non-exposed) snow concentrations, depending on the reaction rate. This would indicate that a

  7. Unraveling the Complexity of Atmospheric Aerosol: Insights from Ultrahigh Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Mazzoleni, Lynn R.; Zhao, Yunzhu; Samburova, Vera; Gannet Hallar, A.; Lowenthal, Douglas

    2016-04-01

    Atmospheric aerosol organic matter (AOM) is a complex mixture of thousands of organic compounds, which may have significant influence on the climate-relevant properties of atmospheric aerosols. An improved understanding of the molecular composition of AOM is needed to evaluate the effect of aerosol composition upon aerosol physical properties. Products of gas, aqueous and particle phase reactions contribute to the aerosol organic mass. Thus, ambient aerosols carry a complex array of AOM components with variable chemical signatures depending upon its origin and aerosol life-cycle processes. In this work, ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize ambient aerosol AOM collected at the Storm Peak Laboratory (3210 m a.s.l.) near Steamboat Springs, CO. Thousands of molecular formulas were assigned in the mass range of m/z 100-800 after negative-ion electrospray ionization. Using multivariate statistical analysis, correlations between the site meteorological conditions and specific molecular compositions were identified. For example, days with strong UV radiation and high temperature were found to contain large numbers of biogenic SOA molecular formulas. Similarly, days with high relative humidity and high sulfate concentrations were found to contain many sulfur-containing compounds, suggesting their aqueous phase formation.

  8. Estimation of columnar concentrations of absorbing and scattering fine mode aerosol components using AERONET data

    NASA Astrophysics Data System (ADS)

    Choi, Yongjoo; Ghim, Young Sung

    2016-11-01

    Columnar concentrations of absorbing and scattering components of fine mode aerosols were estimated using Aerosol Robotic Network (AERONET) data for a site downwind of Seoul. The study period was between March 2012 and April 2013 including the period of the Distributed Regional Aerosol Gridded Observation Networks (DRAGON)-Asia campaign in March to May 2012. The Maxwell Garnett mixing rule was assumed for insoluble components embedded in a host solution, while the volume average mixing rule was assumed for the aqueous solution of soluble components. During the DRAGON-Asia campaign the surface concentrations of major components of fine particles were measured. The columnar mass fractions of black carbon (BC), organic carbon (OC), mineral dust (MD), and ammonium sulfate (AS) were 1.5, 5.9, 6.6, and 52%, respectively, which were comparable to the mass fractions measured at the surface for BC, OC, and secondary inorganic aerosols at 2.3, 18, and 55%. The vertical distributions of BC and AS were investigated by employing the concept of a column height. While the column height for BC was similar to the planetary boundary layer (PBL) height, that for AS was 4.4 times higher than the PBL height and increased with air temperature from March to May. The monthly variations of the columnar mass concentrations during the study period were generally well explained in term of meteorology and emission characteristics. However, certain variations of MD were different from those typically observed primarily because only fine mode aerosols were considered.

  9. Laboratory and field measurements of organic aerosols with the photoionization aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Dreyfus, Matthew A.

    Analytical methods developed to sample and characterize ambient organic aerosols often face the trade-off between long sampling times and the loss of detailed information regarding specific chemical species present. The soft, universal ionization scheme of the Photoionization Aerosol Mass Spectrometer (PIAMS) allows for identification of various chemical compounds by a signature ion, often the molecular ion. The goal of this thesis work is to apply PIAMS to both laboratory and field experiments to answer questions regarding the formation, composition, and behavior of organic aerosols. To achieve this goal, a variety of hardware and software upgrades were administered to PIAMS to optimize the instrument. Data collection and processing software were either refined or built from the ground up to simplify difficult or monotonous tasks. Additional components were added to PIAMS with the intent to automate the instrument, enhance the results, and make the instrument more rugged and user-friendly. These changes, combined with the application of an external particle concentration system (mini-Versatile Aerosol Concentration Enrichment System, m-VACES), allowed PIAMS to be suitable for field measurements of organic aerosols. Two such field campaigns were completed, both at the State of Delaware Air Quality Monitoring Site in Wilmington, Delaware: a one week period in June, 2006, and an 18 day period in October and November of 2007. A sampling method developed was capable of collecting sufficient ambient organic aerosol and analyzing it with a time resolution of 3.5 minutes. Because of this method, short term concentration changes of individual species can be tracked. Combined with meteorological data, the behavior of these species can be analyzed as a function of time or wind direction. Many compounds are found at enhanced levels during the evening/night-time hours; potentially due to the combined effects of temperature inversion, and fresh emissions in a cooler environment

  10. Aerosol ion concentration dependence on atmospheric conditions in Chicago

    NASA Astrophysics Data System (ADS)

    Fosco, Tinamarie; Schmeling, Martina

    This study seeks to determine the influence of precursor trace gases and local meteorology, including lake breeze events, on the concentrations of secondary aerosol species in Chicago. For this, two particulate air samples per day were collected onto quartz fiber filters at the Loyola University Chicago Air Station (LUCAS) during the summer months of 2002 and 2003 and subsequently analyzed by ion chromatography for sulfate, nitrate and oxalate. In parallel, mixing ratios of ozone (O 3) and nitrogen oxides (NO and NO 2dbnd NO x) were monitored and weather parameters were recorded. In addition, backward trajectories were obtained to estimate air mass transport to Chicago. Ozone and NO x mixing ratios as well as sulfate, nitrate and oxalate concentrations varied substantially throughout the study, but three situations could be distinguished based on meteorology and chemistry. Case one had the lowest ozone, NO x and ion levels due to wind directions constantly from Lake Michigan. Case two comprised of days showing the highest pollutant levels because of to predominantly southwestern air currents and warm temperatures and case three experienced an air stagnation situation in the morning leading to high NO x mixing ratios and a subsequent lake breeze event. In the last case, elevated ozone mixing ratios and ion concentrations were observed after lake breeze onset indicating pollutant transport.

  11. Calculating Capstone depleted uranium aerosol concentrations from beta activity measurements.

    PubMed

    Szrom, Frances; Falo, Gerald A; Parkhurst, Mary Ann; Whicker, Jeffrey J; Alberth, David P

    2009-03-01

    Beta activity measurements were used as surrogate measurements of uranium mass in aerosol samples collected during the field testing phase of the Capstone Depleted Uranium (DU) Aerosol Study. These aerosol samples generated by the perforation of armored combat vehicles were used to characterize the DU source term for the subsequent Human Health Risk Assessment (HHRA) of Capstone aerosols. Establishing a calibration curve between beta activity measurements and uranium mass measurements is straightforward if the uranium isotopes are in equilibrium with their immediate short-lived, beta-emitting progeny. For DU samples collected during the Capstone study, it was determined that the equilibrium between the uranium isotopes and their immediate short-lived, beta-emitting progeny had been disrupted when penetrators had perforated target vehicles. Adjustments were made to account for the disrupted equilibrium and for wall losses in the aerosol samplers. Values for the equilibrium fraction ranged from 0.16 to 1, and the wall loss correction factors ranged from 1 to 1.92. This paper describes the process used and adjustments necessary to calculate uranium mass from proportional counting measurements.

  12. Characterization of organic aerosols in Beijing using an aerodyne high-resolution aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Zhang, Junke; Wang, Yuesi; Huang, Xiaojuan; Liu, Zirui; Ji, Dongsheng; Sun, Yang

    2015-06-01

    Fine particle of organic aerosol (OA), mostly arising from pollution, are abundant in Beijing. To achieve a better understanding of the difference in OA in summer and autumn, a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, Aerodyne Research Inc., USA) was deployed in urban Beijing in August and October 2012. The mean OA mass concentration in autumn was 30±30 μg m-3, which was higher than in summer (13±6.9 μg m-3). The elemental analysis found that OA was more aged in summer (oxygen-to-carbon (O/C) ratios were 0.41 and 0.32 for summer and autumn, respectively). Positive matrix factorization (PMF) analysis identified three and five components in summer and autumn, respectively. In summer, an oxygenated OA (OOA), a cooking-emission-related OA (COA), and a hydrocarbon-like OA (HOA) were indentified. Meanwhile, the OOA was separated into LV-OOA (low-volatility OOA) and SV-OOA (semi-volatile OOA); and in autumn, a nitrogen-containing OA (NOA) was also found. The SOA (secondary OA) was always the most important OA component, accounting for 55% of the OA in the two seasons. Back trajectory clustering analysis found that the origin of the air masses was more complex in summer. Southerly air masses in both seasons were associated with the highest OA loading, while northerly air masses were associated with the lowest OA loading. A preliminary study of OA components, especially the POA (primary OA), in different periods found that the HOA and COA all decreased during the National Day holiday period, and HOA decreased at weekends compared with weekdays.

  13. Characterization and source apportionment of submicron aerosol with aerosol mass spectrometer during the PRIDE-PRD 2006 campaign

    NASA Astrophysics Data System (ADS)

    Xiao, R.; Takegawa, N.; Zheng, M.; Kondo, Y.; Miyazaki, Y.; Miyakawa, T.; Hu, M.; Shao, M.; Zeng, L.; Gong, Y.; Lu, K.; Deng, Z.; Zhao, Y.; Zhang, Y. H.

    2011-01-01

    Size-resolved chemical compositions of non-refractory submicron aerosol were measured using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) at the rural site Back Garden (BG), located ~50 km northwest of Guangzhou in July 2006. This paper characterized the submicron aerosol particles of regional air pollution in Pearl River Delta (PRD) in the Southern China. Organics and sulfate dominated the submicron aerosol compositions, with average mass concentrations of 11.8±8.4 μg m-3 and 13.5±8.7 μg m-3, respectively. Unlike other air masses, the air masses originated from Southeast-South and passing through the PRD urban areas exhibited distinct bimodal size distribution characteristics for both organics and sulfate: the first mode peaked at vacuum aerodynamic diameters (Dva)~200 nm and the second mode occurred at Dva from 300-700 nm. With the information from AMS, it was found from this study that the first mode of organics in PRD regional air masses was contributed by both secondary organic aerosol formation and combustion-related emissions, which is different from most findings in other urban areas (first mode of organics primarily from combustion-related emissions). The analysis of AMS mass spectra data by positive matrix factorization (PMF) model identified three sources of submicron organic aerosol including hydrocarbon-like organic aerosol (HOA), low volatility oxygenated organic aerosol (LV-OOA) and semi-volatile oxygenated organic aerosol (SV-OOA). The strong correlation between HOA and EC indicated primary combustion emissions as the major source of HOA while a close correlation between SV-OOA and semi-volatile secondary species nitrate as well as between LV-OOA and nonvolatile secondary species sulfate suggested secondary aerosol formation as the major source of SV-OOA and LV-OOA at the BG site. However, LV-OOA was more aged than SV-OOA as its spectra was highly correlated with the reference spectra of fulvic acid, an indicator of aged and

  14. Characterization and source apportionment of submicron aerosol with aerosol mass spectrometer during the PRIDE-PRD 2006 campaign

    NASA Astrophysics Data System (ADS)

    Xiao, R.; Takegawa, N.; Zheng, M.; Kondo, Y.; Miyazaki, Y.; Miyakawa, T.; Hu, M.; Shao, M.; Zeng, L.; Gong, Y.; Lu, K.; Deng, Z.; Zhao, Y.; Zhang, Y. H.

    2011-07-01

    Size-resolved chemical compositions of non-refractory submicron aerosol were measured using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) at the rural site Back Garden (BG), located ~50 km northwest of Guangzhou in July 2006. This paper characterized the submicron aerosol particles of regional air pollution in Pearl River Delta (PRD) in the southern China. Organics and sulfate dominated the submicron aerosol compositions, with average mass concentrations of 11.8 ± 8.4 μg m-3 and 13.5 ± 8.7 μg m-3, respectively. Unlike other air masses, the air masses originated from Southeast-South and passing through the PRD urban areas exhibited distinct bimodal size distribution characteristics for both organics and sulfate: the first mode peaked at vacuum aerodynamic diameters (Dva) ∼200 nm and the second mode occurred at Dva from 300-700 nm. With the information from AMS, it was found from this study that the first mode of organics in PRD regional air masses was contributed by both secondary organic aerosol formation and combustion-related emissions, which is different from most findings in other urban areas (first mode of organics primarily from combustion-related emissions). The analysis of AMS mass spectra data by positive matrix factorization (PMF) model identified three sources of submicron organic aerosol including hydrocarbon-like organic aerosol (HOA), low volatility oxygenated organic aerosol (LV-OOA) and semi-volatile oxygenated organic aerosol (SV-OOA). The strong correlation between HOA and EC indicated primary combustion emissions as the major source of HOA while a close correlation between SV-OOA and semi-volatile secondary species nitrate as well as between LV-OOA and nonvolatile secondary species sulfate suggested secondary aerosol formation as the major source of SV-OOA and LV-OOA at the BG site. However, LV-OOA was more aged than SV-OOA as its spectra was highly correlated with the reference spectra of fulvic acid, an indicator of aged and

  15. Validation of LIRIC aerosol concentration retrievals using airborne measurements during a biomass burning episode over Athens

    NASA Astrophysics Data System (ADS)

    Kokkalis, Panagiotis; Amiridis, Vassilis; Allan, James D.; Papayannis, Alexandros; Solomos, Stavros; Binietoglou, Ioannis; Bougiatioti, Aikaterini; Tsekeri, Alexandra; Nenes, Athanasios; Rosenberg, Philip D.; Marenco, Franco; Marinou, Eleni; Vasilescu, Jeni; Nicolae, Doina; Coe, Hugh; Bacak, Asan; Chaikovsky, Anatoli

    2017-01-01

    In this paper we validate the Lidar-Radiometer Inversion Code (LIRIC) retrievals of the aerosol concentration in the fine mode, using the airborne aerosol chemical composition dataset obtained over the Greater Athens Area (GAA) in Greece, during the ACEMED campaign. The study focuses on the 2nd of September 2011, when a long-range transported smoke layer was observed in the free troposphere over Greece, in the height range from 2 to 3 km. CIMEL sun-photometric measurements revealed high AOD ( 0.4 at 532 nm) and Ångström exponent values ( 1.7 at 440/870 nm), in agreement with coincident ground-based lidar observations. Airborne chemical composition measurements performed over the GAA, revealed increased CO volume concentration ( 110 ppbv), with 57% sulphate dominance in the PM1 fraction. For this case, we compare LIRIC retrievals of the aerosol concentration in the fine mode with the airborne Aerosol Mass Spectrometer (AMS) and Passive Cavity Aerosol Spectrometer Probe (PCASP) measurements. Our analysis shows that the remote sensing retrievals are in a good agreement with the measured airborne in-situ data from 2 to 4 km. The discrepancies observed between LIRIC and airborne measurements at the lower troposphere (below 2 km), could be explained by the spatial and temporal variability of the aerosol load within the area where the airborne data were averaged along with the different time windows of the retrievals.

  16. Lidar detection of high concentrations of ozone and aerosol transported from northeastern Asia over Saga, Japan

    NASA Astrophysics Data System (ADS)

    Uchino, Osamu; Sakai, Tetsu; Izumi, Toshiharu; Nagai, Tomohiro; Morino, Isamu; Yamazaki, Akihiro; Deushi, Makoto; Yumimoto, Keiya; Maki, Takashi; Tanaka, Taichu Y.; Akaho, Taiga; Okumura, Hiroshi; Arai, Kohei; Nakatsuru, Takahiro; Matsunaga, Tsuneo; Yokota, Tatsuya

    2017-02-01

    To validate products of the Greenhouse gases Observing SATellite (GOSAT), we observed vertical profiles of aerosols, thin cirrus clouds, and tropospheric ozone with a mobile-lidar system that consisted of a two-wavelength (532 and 1064 nm) polarization lidar and a tropospheric ozone differential absorption lidar (DIAL). We used these lidars to make continuous measurements over Saga (33.24° N, 130.29° E) during 20-31 March 2015. High ozone and high aerosol concentrations were observed almost simultaneously in the altitude range 0.5-1.5 km from 03:00 to 20:00 Japan Standard Time (JST) on 22 March 2015. The maximum ozone volume mixing ratio was ˜ 110 ppbv. The maxima of the aerosol extinction coefficient and optical depth at 532 nm were 1.2 km-1 and 2.1, respectively. Backward trajectory analysis and the simulations by the Model of Aerosol Species IN the Global AtmospheRe (MASINGAR) mk-2 and the Meteorological Research Institute Chemistry-Climate Model, version 2 (MRI-CCM2), indicated that mineral dust particles from the Gobi Desert and an air mass with high ozone and aerosol (mainly sulfate) concentrations that originated from the North China Plain could have been transported over the measurement site within about 2 days. These high ozone and aerosol concentrations impacted surface air quality substantially in the afternoon of 22 March 2015. After some modifications of its physical and chemical parameters, MRI-CCM2 approximately reproduced the high ozone volume mixing ratio. MASINGAR mk-2 successfully predicted high aerosol concentrations, but the predicted peak aerosol optical thickness was about one-third of the observed value.

  17. Measurement of mass distribution of chemical species in aerosol particles

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.; Friedlander, S. K.

    1984-01-01

    Aerosols may be generated through the nebulizing of solutions and the evaporation of their solvent, leaving the dry solute particles. Attention is presently given to a method for the direct determination of the masses of chemical species in individual aerosol particles on a continuous, real-time basis, using mass spectrometry. After the aerosol particles are introduced into the ion source of a quadrupole mass spectrometer, the particles impinge on a hot rhenium filament in the mass spectrometer's ion source. The resulting vapor plume is ionized by electron bombardment, and a pulse of ions is generated by each particle. The intensities of different masses in the ion pulses can then be measured by the mass spectrometer.

  18. Influence of air mass origin on aerosol properties at a remote Michigan forest site

    NASA Astrophysics Data System (ADS)

    VanReken, T. M.; Mwaniki, G. R.; Wallace, H. W.; Pressley, S. N.; Erickson, M. H.; Jobson, B. T.; Lamb, B. K.

    2015-04-01

    The northern Great Lakes region of North America is a large, relatively pristine area. To date, there has only been limited study of the atmospheric aerosol in this region. During summer 2009, a detailed characterization of the atmospheric aerosol was conducted at the University of Michigan Biological Station (UMBS) as part of the Community Atmosphere-Biosphere Interactions Experiment (CABINEX). Measurements included particle size distribution, water-soluble composition, and CCN activity. Aerosol properties were strongly dependent on the origin of the air masses reaching the site. For ∼60% of the study period, air was transported from sparsely populated regions to the northwest. During these times aerosol loadings were low, with mean number and volume concentrations of 1630 cm-3 and 1.91 μm3 cm-3, respectively. The aerosol during clean periods was dominated by organics, and exhibited low hygroscopicities (mean κ = 0.18 at s = 0.3%). When air was from more populated regions to the east and south (∼29% of the time), aerosol properties reflected a stronger anthropogenic influence, with 85% greater particle number concentrations, 2.5 times greater aerosol volume, six times more sulfate mass, and increased hygroscopicity (mean k = 0.24 at s = 0.3%). These trends are have the potential to influence forest-atmosphere interactions and should be targeted for future study.

  19. Evaluating Simulations of Primary Anthropogenic and Biomass Burning Organic Aerosols using Aerosol Mass Spectrometer Data and Positive Matrix Factorization Analysis

    NASA Astrophysics Data System (ADS)

    Fast, J.; Aiken, A.; Alexander, L.; Canagaratna, M.; Decarlo, P.; Herndon, S.; Jimenez, J.; Kleinman, L.; Ochoa, C.; Onasch, T.; Song, C.; Wiedinmyer, C.; Yu, X.; Zaveri, R.

    2008-12-01

    Most model predictions of organic matter are currently underestimated because the processes contributing to secondary organic aerosol (SOA) formation and transformation are not well understood. Since research associated with developing a better framework to improve the representation of specific gas-to-particle partitioning processes controlling SOA based on new measurements and theoretical relationships is on- going, this study seeks to determine whether 3-D models can adequately predict concentrations of primary organic aerosols (POA). If one assumes POA is non-volatile, then errors in POA predictions will results from uncertainties in the emission inventories and errors in transport and mixing processes. The WRF-chem model is used to predict POA in the vicinity of Mexico City during the 2006 MILAGRO field campaign. Particulate matter emission rates were obtained from urban and regional Mexican emission inventories and from biomass burning estimates derived from MODIS "hotspot" and vegetation databases. Organic aerosol predictions are evaluated using data from Aerodyne Aerosol Mass Spectrometer (AMS) instruments deployed at four ground sites and on two research aircraft and from Sunset Laboratory OCEC instruments deployed at two ground sites. Positive Matrix Factorization (PMF) has recently been applied to derive components of organic aerosols including: hydrocarbon-like organic aerosol (HOA), oxidized organic aerosol (OOA), and biomass burning organic aerosols (BBOA). The temporal variation of HOA is often similar to primary emissions of other species in urban areas. PMF analysis is currently available for three of the ground sites and for some of the aircraft flights. We found that the predicted POA was consistently lower than the measured organic matter at the ground sites, which is consistent with the expectation that SOA should be a large fraction of the total organic aerosol mass. A much better agreement was found when predicted POA was compared with HOA

  20. MCS precipitation and downburst intensity response to increased aerosol concentrations

    NASA Astrophysics Data System (ADS)

    Clavner, M.; Cotton, W. R.; van den Heever, S. C.

    2015-12-01

    Mesoscale convective systems (MCSs) are important contributors to rainfall in the High Plains of the United States as well as producers of severe weather such as hail, tornados and straight-line wind events known as derechos. Past studies have shown that changes in aerosol concentrations serving as cloud condensation nuclei (CCN) alter the MCS hydrometeor characteristics which in turn modify precipitation yield, downdraft velocity, cold-pool strength, storm propagation and the potential for severe weather to occur. In this study, the sensitivity of MCS precipitation characteristics and convective downburst velocities associated with a derecho to changes in CCN concentrations were examined by simulating a case study using the Regional Atmospheric Modeling System (RAMS). The case study of the 8 May 2009 "Super-Derecho" MCS was chosen since it produced a swath of widespread wind damage in association with an embedded large-scale bow echo, over a broad region from the High Plains of western Kansas to the foothills of the Appalachians. The sensitivity of the storm to changes in CCN concentrations was examined by conducting a set of three simulations which differed in the initial aerosol concentration based on output from the 3D chemical transport model, GEOS-Chem. Results from this study indicate that while increasing CCN concentrations led to an increase in precipitation rates, the changes to the derecho strength were not linear. A moderate increase in aerosol concentration reduced the derecho strength, while the simulation with the highest aerosol concentrations increased the derecho intensity. These changes are attributed to the impact of enhanced CCN concentration on the production of convective downbursts. An analysis of aerosol loading impacts on these MCS features will be presented.

  1. Spatial variability of carbonaceous aerosol concentrations in East and West Jerusalem.

    PubMed

    von Schneidemesser, Erika; Zhou, Iiabin; Stone, Elizabeth A; Schauer, James I; Shpund, Jacob; Brenner, Shmuel; Qasrawi, Radwan; Abdeen, Ziad; Sarnat, Jeremy A

    2010-03-15

    Carbonaceous aerosol concentrations and sources were compared during a year long study at two sites in East and West Jerusalem that were separated by a distance of approximately 4 km. One in six day 24-h PM(2.5) elemental and organic carbon concentrations were measured, along with monthly average concentrations of particle-phase organic compound tracers for primary and secondary organic aerosol sources.Tracer compounds were used in a chemical mass balance ICMB) model to determine primary and secondary source contributions to organic carbon. The East Jerusalem sampling site at Al Quds University experienced higher concentrations of organic carbon (OC) and elemental carbon (EC) compared to the West Jerusalem site at Hebrew University. The annual average concentrations of OC and EC at the East Jerusalem site were 5.20 and 2.19 μg m(-3), respectively, and at the West Jerusalem site were 4.03 and 1.14 μg m(-3), respectively. Concentrations and trends of secondary organic aerosol and vegetative detritus were similar at both sites, but large differences were observed in the concentrations of organic aerosol from fossil fuel combustion and biomass burning, which was the cause of the large differences in OC and EC concentrations observed at the two sites.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  3. Secondary Aerosol Formation in the planetary boundary layer observed by aerosol mass spectrometry on a Zeppelin NT

    NASA Astrophysics Data System (ADS)

    Rubach, Florian; Trimborn, Achim; Mentel, Thomas; Wahner, Andreas; Zeppelin Pegasos-Team 2012

    2014-05-01

    The airship Zeppelin NT is an airborne platform capable of flying at low speed throughout the entire planetary boundary layer (PBL). In combination with the high scientific payload of more than 1 ton, the Zeppelin is an ideal platform to study regional processes in the lowest layers of the atmosphere with high spatial resolution. Atmospheric aerosol as a medium long lived tracer substance is of particular interest due to its influence on the global radiation budget. Due its lifetime of up to several days secondaray aerosol at a certain location can result from local production or from transport processes. For aerosol measurements on a Zeppelin, a High-Resolution Time-of-Flight Aerosol Mass spectrometer (DeCarlo et al, 2006) was adapted to the requirements posed by an airborne platform. A weight reduction of over 20 % compared to the commercial instrument was achieved, while space occupation and footprint were each reduced by over 25 %. Within the PEGASOS project, the instrument was part of 10 measurement flight days over the course of seven weeks. Three flights were starting from Rotterdam, NL, seven flights were starting from Ozzano in the Po Valley, IT. Flight patterns included vertical profiles to study the dynamics of the PBL and cross sections through regions of interest to shed light on local production and transport processes. Analysis of data from transects between the Apennin and San Pietro Capofiume in terms of "residence time of air masses in the Po valley" indicates that aerosol nitrate has only local sources while aerosol sulfate is dominated by transport. The organic aerosol component has significant contributions of both processes. The local prodcution yields are commensurable with imultaneously observed precursor concentrations and oxidant levels. The PEGASOS project is funded by the European Commission under the Framework Programme 7 (FP7-ENV-2010-265148). DeCarlo, P.F. et al (2006), Anal. Chem., 78, 8281-8289.

  4. Source contributions to black carbon mass fractions in aerosol particles over the northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Koga, Seizi; Maeda, Takahisa; Kaneyasu, Naoki

    Aerosol particle number size distributions above 0.3 μm in diameter and black carbon mass concentrations in aerosols were observed on Chichi-jima of the Ogasawara Islands in the northwestern Pacific from January 2000 to December 2002. Chichi-jima is suitable to observe polluted air masses from East Asia in winter and clean air masses over the western North Pacific in summer. In winter, aerosols over Chichi-jima were strongly affected by anthropogenic emissions in East Asia. The form of energy consumption in East Asia varies in various regions. Hence, each source region is expected to be characterized by an individual black carbon mass fraction. A three-dimensional Eulerian transport model was used to estimate contribution rates to air pollutants from each source region in East Asia. Because the Miyake-jima eruption began at the end of June 2000, the influence of smokes from Miyake-jima was also considered in the model calculation. The results of model calculations represent what must be noticed about smokes from volcanoes including Miyake-jima to interpret temporal variations of sulfur compounds over the northwestern Pacific. To evaluate black carbon mass fractions in anthropogenic aerosols as a function of source region, the relationships between the volume concentration of aerosol particles and the black carbon mass concentration in the winter were classified under each source region in East Asia. Consequently, the black carbon mass fractions in aerosols from China, Japan and the Korean Peninsula, and other regions were estimated to be 9-13%, 5-7%, and 4-5%, respectively.

  5. Source contributions to carbonaceous aerosol concentrations in Korea

    NASA Astrophysics Data System (ADS)

    Jeong, Jaein I.; Park, Rokjin J.; Woo, Jung-Hun; Han, Young-Ji; Yi, Seung-Muk

    2011-02-01

    We estimated the source contributions to carbonaceous aerosol concentration in Korea on the basis of Intercontinental Chemical Transport Experiment Phase B (INTEX-B) anthropogenic emissions and satellite-derived biomass burning emissions by using a nested version of GEOS-Chem with a spatial resolution of 0.5° × 0.667° for the period March 2006-February 2007. First, we evaluated the model by comparing the simulated and observed aerosol concentrations at East Asia Network (EANET) sites and at a site in Korea. The results indicate that the model reproduces the variability and magnitudes of the observed SO 42-, NO 3-, and NH 4+ concentrations in Korea and those of the observed PM 10 concentrations in East Asia. However, the organic carbon (OC) and black carbon (BC) aerosol concentrations estimated by the model are lower than those observed in Korea by a factor of 2, especially in winter. This underestimation is likely due to extremely low domestic anthropogenic emissions and lack in seasonal variation. Source adjustments using a simple fitting and the Emission Database for Global Atmospheric Research (EDGAR) monthly allocation factors for seasonal variation yield significantly improved model results ( R2 increased from 0.58 to 0.84), which can then be used to estimate the source contributions to the OC and BC concentrations in Korea. We found that domestic anthropogenic emissions are the most important factors, contributing 74% (9% from fossil fuels and 65% from biofuels) and 78% (42% from fossil fuels and 36% from biofuels) to the OC and BC concentrations, respectively, on an annual mean basis in Korea. The trans-boundary transport of Chinese sources is another important factor, contributing 13% and 20% to the OC and BC concentrations, respectively. The contributions of wildfires and biogenic sources to the annual mean carbonaceous aerosol concentration in Korea are relatively small (4% and 6%, respectively).

  6. On the implications of aerosol liquid water and phase separation for organic aerosol mass

    NASA Astrophysics Data System (ADS)

    Pye, Havala O. T.; Murphy, Benjamin N.; Xu, Lu; Ng, Nga L.; Carlton, Annmarie G.; Guo, Hongyu; Weber, Rodney; Vasilakos, Petros; Wyat Appel, K.; Hapsari Budisulistiorini, Sri; Surratt, Jason D.; Nenes, Athanasios; Hu, Weiwei; Jimenez, Jose L.; Isaacman-VanWertz, Gabriel; Misztal, Pawel K.; Goldstein, Allen H.

    2017-01-01

    Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to organic carbon (OM / OC) ratios are high such that separation relative humidities (SRH) are below the ambient relative humidity (RH). As OM / OC ratios in the SE US are often between 1.8 and 2.2, organic aerosol experiences both mixing with inorganic water and separation from it. Regional chemical transport model simulations including inorganic water (but excluding water uptake by organic compounds) in the partitioning medium for secondary organic aerosol (SOA) when RH > SRH led to increased SOA concentrations, particularly at night. Water uptake to the organic phase resulted in even greater SOA concentrations as a result of a positive feedback in which water uptake increased SOA, which further increased aerosol water and organic aerosol. Aerosol properties, such as the OM / OC and hygroscopicity parameter (κorg), were captured well by the model compared with measurements during the Southern Oxidant and Aerosol Study (SOAS) 2013. Organic nitrates from monoterpene oxidation were predicted to be the least water-soluble semivolatile species in the model, but most biogenically derived semivolatile species in the Community Multiscale Air Quality (CMAQ) model were highly water soluble and expected to contribute to water-soluble organic carbon (WSOC). Organic aerosol and SOA precursors were abundant at night, but additional improvements in daytime organic aerosol are needed to close the model-measurement gap. When taking into account deviations from ideality, including both inorganic (when RH > SRH) and organic water in the organic partitioning medium reduced the mean bias in SOA for routine monitoring networks and improved model performance compared to observations from SOAS. Property updates from

  7. Variations of the aerosol concentration and chemical composition over the arid steppe zone of Southern Russia in summer

    NASA Astrophysics Data System (ADS)

    Artamonova, M. S.; Gubanova, D. P.; Iordanskii, M. A.; Lebedev, V. A.; Maksimenkov, L. O.; Minashkin, V. M.; Obvintsev, Y. I.; Chketiani, O. G.

    2016-12-01

    Variations in the surface aerosol over the arid steppe zone of Southern Russia have been measured. The parameters of atmospheric aerosol (mass concentration, both dispersed and elemental compositions) and meteorological parameters were measured in Tsimlaynsk raion (Rostov oblast). The chemical composition of aerosol particles in the atmospheric surface layer has been determined, and the coefficients of enrichment of elements with respect to clarkes in the Earth's crust have been calculated. It is shown that, in summer, arid aerosols are transported from both alkaline and sandy soils of Kalmykia to the air basin over the observation zone. Aerosol particles in the surface air layer over this region have been found to contain the products of combustion of oil, coal, and ethylized fuel. These combustion products make a small contribution to the total mass concentration of atmospheric aerosol; however, they are most hazardous to the health of people because of their sizes and heavy-metal contents. A high concentration of submicron sulfur-containing aerosol particles of chemocondensation nature has been recorded. Sources of aerosol of both natural and anthropogenic origins in southern Russia are discussed.

  8. Design and Fabrication of an Aerosol Concentrator.

    DTIC Science & Technology

    1980-05-08

    MBEran GpVt 08C IO NO 3. RECIPIENT’S CATALOG NUMBER 4. TITL S. VVIREOP ePORT A PERIOD COVERED Interim report on a continuing ~ESIGN AND ,BRICATION OF AN...electronic tachometer , and a variable speed controller. Our motor is a hand-held router motor, model 90114, manufactured by the Stanley Power Tool Company (P.O...be obtained from Lordco Supply (Erie, PA 16505). Since the concentrator is run at various speeds, we incorporated an electronic tachometer into the

  9. Aerosol formation by ozonolysis of α- and β-pinene with initial concentrations below 1 ppb

    NASA Astrophysics Data System (ADS)

    Saathoff, Harald; Naumann, Karl-Heinz; Möhler, Ottmar

    2014-05-01

    Secondary organic aerosols (SOA) from the oxidation of biogenic volatile organic compounds (BVOC) are a large fraction of the tropospheric aerosol especially over tropical continental regions. The dominant SOA forming compounds are monoterpenes of which pinene is the most abundant. The reactions of monoterpenes with OH radicals, NO3 radicals, and ozone yield secondary organic aerosol mass in highly variable yields. Despite the various studies on SOA formation the influence of temperature and precursor concentrations on SOA yields are still major uncertainties in tropospheric aerosol models. In previous studies we observed a negative temperature dependence of SOA yields for SOA from ozonolysis α-pinene and limonene (Saathoff et al., 2009). However, this study as well as most of the literature data for measured SOA yields is limited to terpene concentrations of several ppb and higher (e.g. Bernard et al., 2012), hence about an order of magnitude higher than terpene concentrations even near their sources. Monoterpene concentrations in and above tropical or boral forests reach values up to a few tenth of a ppb during daytime decreasing rapidly with altitude in the boundary layer (Kesselmeier et al. 2000; Boy et al., 2004). Therefore we investigated the yield of SOA material from the ozonolysis of α- and β-pinene under simulated tropospheric conditions in the large aerosol chamber AIDA on time scales of several hours and for terpene concentrations between 0.1 and 1 ppb. The temperatures investigated were 243, 274, and 296 K with relative humidities ranging from 25% to 41%. The organic aerosol was generated by controlled oxidation with an excess of ozone (220-930 ppb) and the aerosol yield is calculated from size distributions measured with differential mobility analysers (SMPS, TSI, 3071 & 3080N) in the size range between 2 and 820 nm. On the basis of the measured initial particle size distribution, particle number concentration (CPC, TSI, 3775, 3776, 3022), and

  10. Concentrations and size distributions of Antarctic stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Ferry, G. V.; Pueschel, R. F.; Neish, E.; Schultz, M.

    1989-01-01

    Particle Measuring Systems laser particle spectrometer (ASAS-X and FSSP) probes were used to measure aerosol particle concentrations and size distributions during 11 ER-2 flights between Punta Arenas (53 deg S) and Antarctica (up to 72 deg S) from August 17 to September 22, 1987. The time resolution was 10 s, corresponding to a spatial resolution of 2 km. The data were divided into two size classes (0.05-0.25 and 0.53-5.5 micron radius) to separate the small particle from the coarse particle populations. Results show that the small-particle concentrations are typical for a background aerosol during volcanic quiescence. This concentration is generally constant along a flight track; in only one instance a depletion of small particles during a polar stratospheric cloud (PSC) encounter was measured, suggesting a nucleation of type I PSC particles on background aerosols. Temporary increases of the coarse particle concentrations indicated the presence of tenuous polar stratospheric clouds that were encountered most frequently at the southernmost portion of a flight track and when the aircraft descended to lower altitudes. During 'particle events', particle modes were found at 0.6-micron radius, corresponding to type I PSCs, and occasionally, at 2.0-micron radius corresponding to type II PSCs.

  11. Formation and Processing of Organic Aerosols Measured by a Time of Flight Aerosol Mass Spectrometer during TexAQS/GoMACCS 2006

    NASA Astrophysics Data System (ADS)

    Bahreini, R.; Middlebrook, A. M.; Decarlo, P. F.; Denlea, E.; Jimenez, J. L.; Brock, C. A.; Degouw, J. A.; Flocke, F.; Gallar, C.; Holloway, J. S.; Neuman, J. A.; Ryerson, T. B.; Schwarz, J. P.; Spackman, J. R.; Trainer, M. K.; Warneke, C.; Wollny, A. G.; Zhang, W.; Fehsenfeld, F. C.

    2007-12-01

    Formation of particulate matter is common in areas with high emissions of volatile organic compounds (VOCs), NOx, and SO2. These particles have lifetimes of days to weeks, and thus can have both local and regional effects on visibility, air quality, and human health as well as direct and indirect effects on climate. During TexAQS 2006, mass concentrations of non-refractory inorganic species (sulfate, ammonium, and nitrate) and total organics in submicron aerosols were measured by a Compact Time of Flight Aerosol Mass Spectrometer (C-ToF-AMS) onboard the NOAA WP-3D aircraft. In this presentation, we analyze composition changes of organic aerosols in different air masses. We examine organic mass spectra along with simultaneous measurements of VOCs and their oxidation products in order to determine the contribution of anthropogenic and biogenic sources to the aerosol organic mass. These measurements were performed in plumes intercepted during the daytime north of Houston where large isoprene emissions were observed. Furthermore, the fresh hydrocarbon-like (HOA) and processed oxygenated-like organics (OOA) fractions of the total organic aerosol mass in several plumes transected during daytime and nighttime are presented and compared. We will also discuss differences in correlations between organic aerosol composition markers and primary or secondary gas-phase species in different plumes.

  12. Chemical characterization of submicron aerosol particles during wintertime in a northwest city of China using an Aerodyne aerosol mass spectrometry.

    PubMed

    Zhang, Xinghua; Zhang, Yangmei; Sun, Junying; Yu, Yangchun; Canonaco, Francesco; Prévôt, Andre S H; Li, Gang

    2017-03-01

    An Aerodyne quadrupole aerosol mass spectrometry (Q-AMS) was utilized to measure the size-resolved chemical composition of non-refractory submicron particles (NR-PM1) from October 27 to December 3, 2014 at an urban site in Lanzhou, northwest China. The average NR-PM1 mass concentration was 37.3 μg m(-3) (ranging from 2.9 to 128.2 μg m(-3)) under an AMS collection efficiency of unity and was composed of organics (48.4%), sulfate (17.8%), nitrate (14.6%), ammonium (13.7%), and chloride (5.7%). Positive matrix factorization (PMF) with the multi-linear engine (ME-2) solver identified six organic aerosol (OA) factors, including hydrocarbon-like OA (HOA), coal combustion OA (CCOA), cooking-related OA (COA), biomass burning OA (BBOA) and two oxygenated OA (OOA1 and OOA2), which accounted for 8.5%, 20.2%, 18.6%, 12.4%, 17.8% and 22.5% of the total organics mass on average, respectively. Primary emissions were the major sources of fine particulate matter (PM) and played an important role in causing high chemically resolved PM pollution during wintertime in Lanzhou. Back trajectory analysis indicated that the long-range regional transport air mass from the westerly was the key factor that led to severe submicron aerosol pollution during wintertime in Lanzhou.

  13. Spatial variability of aerosol and black carbon concentrations in the troposphere of the Russian Arctic

    NASA Astrophysics Data System (ADS)

    Kozlov, Valerii S.; Panchenko, Mikhail V.; Paris, Jean D.; Nédéléc, Philippe; Chernov, Dmitry G.; Shmargunov, Vladimir P.

    2015-11-01

    A cycle of flights of the Optik TU-134 Flying Laboratory of IAO SB RAS over regions of Western Siberia and the Russian Arctic (55.0-74.8°N, 61.3-82.9°E) was carried out on October 15-17 of 2014 within the framework of the YAK-AEROSIB Russian—French Project. The mass concentrations of submicron aerosol and Black Carbon (BC) in the troposphere up to a height of 8.5 km were measured in the flights. The ranges of variability were 0.3-20 μg/m3 for the aerosol concentration and 0.02-1 μg/m3 for the BC concentration. In the subpolar latitudes of 71-74.8°N, the lower levels of aerosol (0.8-6 μg/m3) and BC (0.02-0.3 μg/m3) were observed. The comparison of the results of airborne sensing in 2008 and 2014 has shown that in the Western Subartic the aerosol and BC concentrations in the vertical profiles up to six times exceeded those observed in the Eastern Subarctic (0.3-1 μg/m3 and 10-50 ng/m3). The excess of the mean integral BC concentrations and the aerosol optical depth was, on average, 2-2.5 times (0.16 mg/m2; 0.02). In the region of the Kara Sea at heights of 0.5-2 and 4-6 km, the excess of the aerosol content in the western sector in comparison with the eastern one was, on average, 2 times, while for the black carbon the excess achieved 7 times at heights of 1-2 km (0.25- 0.035 μg/m3). The mean integral concentrations of aerosol and black carbon ˜ 1.3 times exceeded those in the clearer eastern region of the sea (0.31 mg/m2; 0.049). The obtained estimates indicate the decrease of the aerosol and BC concentrations in the subpolar latitudes of the Russian Federation from the west to the east.

  14. Sensitivity of warm-frontal processes to cloud-nucleating aerosol concentrations

    NASA Technical Reports Server (NTRS)

    Igel, Adele L.; Van Den Heever, Susan C.; Naud, Catherine M.; Saleeby, Stephen M.; Posselt, Derek J.

    2013-01-01

    An extratropical cyclone that crossed the United States on 9-11 April 2009 was successfully simulated at high resolution (3-km horizontal grid spacing) using the Colorado State University Regional Atmospheric Modeling System. The sensitivity of the associated warm front to increasing pollution levels was then explored by conducting the same experiment with three different background profiles of cloud-nucleating aerosol concentration. To the authors' knowledge, no study has examined the indirect effects of aerosols on warm fronts. The budgets of ice, cloud water, and rain in the simulation with the lowest aerosol concentrations were examined. The ice mass was found to be produced in equal amounts through vapor deposition and riming, and the melting of ice produced approximately 75% of the total rain. Conversion of cloud water to rain accounted for the other 25%. When cloud-nucleating aerosol concentrations were increased, significant changes were seen in the budget terms, but total precipitation remained relatively constant. Vapor deposition onto ice increased, but riming of cloud water decreased such that there was only a small change in the total ice production and hence there was no significant change in melting. These responses can be understood in terms of a buffering effect in which smaller cloud droplets in the mixed-phase region lead to both an enhanced vapor deposition and decreased riming efficiency with increasing aerosol concentrations. Overall, while large changes were seen in the microphysical structure of the frontal cloud, cloud-nucleating aerosols had little impact on the precipitation production of the warm front.

  15. 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.

  16. 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.

  17. 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

  18. Mass spectra deconvolution of low, medium, and high volatility biogenic secondary organic aerosol.

    PubMed

    Kostenidou, Evangelia; Lee, Byong-Hyoek; Engelhart, Gabriella J; Pierce, Jeffrey R; Pandis, Spyros N

    2009-07-01

    Secondary organic aerosol (SOA) consists of compounds with a wide range of volatilities and its ambient concentration is sensitive to this volatility distribution. Recent field studies have shown that the typical mass spectrum of ambient oxygenated organic aerosol (OOA) as measured by the Aerodyne Aerosol Mass Spectrometer (AMS) is quite different from the SOA mass spectra reported in smog chamber experiments. Part of this discrepancy is due to the dependence of SOA composition on the organic aerosol concentration. High precursor concentrations lead to higher concentrations of the more volatile species in the produced SOA while at lower concentrations the less volatile compounds dominate the SOA composition. alpha-Pinene, beta-pinene, d-limonene, and beta-caryophyllene ozonolysis experiments were performed at moderate concentration levels. Using a thermodenuder the more volatile SOA species were removed achieving even lower SOA concentration. The less volatile fraction was then chemically characterized by an AMS. The signal fraction of m/z44, and thus the concentration of C02+, is significantly higher for the less volatile SOA. High NO(x) conditions result in less oxidized SOA than low NO(x) conditions, while increasing relative humidity levels results in more oxidized products for limonene but has little effect on alpha-and beta-pinene SOA. Combining a smog chamber with a thermodenuder model employing the volatility basis-set framework, the AMS SOA mass spectrum for each experiment and for each precursor is deconvoluted into low, medium, and high volatility component mass spectra. The spectrum of the surrogate component with the lower volatility is quite similar to that of ambient OOA.

  19. Characterization of ambient aerosols at the San Francisco International Airport using BioAerosol Mass Spectrometry

    SciTech Connect

    Steele, P T; McJimpsey, E L; Coffee, K R; Fergenson, D P; Riot, V J; Tobias, H J; Woods, B W; Gard, E E; Frank, M

    2006-03-16

    The BioAerosol Mass Spectrometry (BAMS) system is a rapidly fieldable, fully autonomous instrument that can perform correlated measurements of multiple orthogonal properties of individual aerosol particles. The BAMS front end uses optical techniques to nondestructively measure a particle's aerodynamic diameter and fluorescence properties. Fluorescence can be excited at 266nm or 355nm and is detected in two broad wavelength bands. Individual particles with appropriate size and fluorescence properties can then be analyzed more thoroughly in a dual-polarity time-of-flight mass spectrometer. Over the course of two deployments to the San Francisco International Airport, more than 6.5 million individual aerosol particles were fully analyzed by the system. Analysis of the resulting data has provided a number of important insights relevant to rapid bioaerosol detection, which are described here.

  20. Detection of cw-related species in complex aerosol particles deposited on surfaces with an ion trap-based aerosol mass spectrometer

    SciTech Connect

    Harris, William A; Reilly, Pete; Whitten, William B

    2007-01-01

    A new type of aerosol mass spectrometer was developed by minimal modification of an existing commercial ion trap to analyze the semivolatile components of aerosols in real time. An aerodynamic lens-based inlet system created a well-collimated particle beam that impacted into the heated ionization volume of the commercial ion trap mass spectrometer. The semivolatile components of the aerosols were thermally vaporized and ionized by electron impact or chemical ionization in the source. The nascent ions were extracted and injected into the ion trap for mass analysis. The utility of this instrument was demonstrated by identifying semivolatile analytes in complex aerosols. This study is part of an ongoing effort to develop methods for identifying chemical species related to CW agent exposure. Our efforts focused on detection of CW-related species doped on omnipresent aerosols such as house dust particles vacuumed from various surfaces found in any office building. The doped aerosols were sampled directly into the inlet of our mass spectrometer from the vacuumed particle stream. The semivolatile analytes were deposited on house dust and identified by positive ion chemical ionization mass spectrometry up to 2.5 h after deposition. Our results suggest that the observed semivolatile species may have been chemisorbed on some of the particle surfaces in submonolayer concentrations and may remain hours after deposition. This research suggests that identification of trace CW agent-related species should be feasible by this technique.

  1. Urban increments of gaseous and aerosol pollutants and their sources using mobile aerosol mass spectrometry measurements

    NASA Astrophysics Data System (ADS)

    Elser, Miriam; Bozzetti, Carlo; El-Haddad, Imad; Maasikmets, Marek; Teinemaa, Erik; Richter, Rene; Wolf, Robert; Slowik, Jay G.; Baltensperger, Urs; Prévôt, André S. H.

    2016-06-01

    Air pollution is one of the main environmental concerns in urban areas, where anthropogenic emissions strongly affect air quality. This work presents the first spatially resolved detailed characterization of PM2.5 (particulate matter with aerodynamic equivalent diameter daero ≤ 2.5 µm) in two major Estonian cities, Tallinn and Tartu. The measurements were performed in March 2014 using a mobile platform. In both cities, the non-refractory (NR)-PM2.5 was characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) using a recently developed lens which increases the transmission of super-micron particles. Equivalent black carbon (eBC) and several trace gases including carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were also measured. The chemical composition of PM2.5 was found to be very similar in the two cities. Organic aerosol (OA) constituted the largest fraction, explaining on average about 52 to 60 % of the PM2.5 mass. Four sources of OA were identified using positive matrix factorization (PMF): hydrocarbon-like OA (HOA, from traffic emissions), biomass burning OA (BBOA, from biomass combustion), residential influenced OA (RIOA, probably mostly from cooking processes with possible contributions from waste and coal burning), and oxygenated OA (OOA, related to secondary aerosol formation). OOA was the major OA source during nighttime, explaining on average half of the OA mass, while during daytime mobile measurements the OA was affected by point sources and dominated by the primary fraction. A strong increase in the secondary organic and inorganic components was observed during periods with transport of air masses from northern Germany, while the primary local emissions accumulated during periods with temperature inversions. Mobile measurements offered the identification of different source regions within the urban areas and the assessment of the extent to which pollutants concentrations exceeded regional background

  2. THE MASS ACCOMMODATION COEFFICIENT OF AMMONIUM NITRATE AEROSOL. (R823514)

    EPA Science Inventory

    The mass transfer rate of pure ammonium nitrate between the aerosol and gas phases was
    quantified experimentally by the use of the tandem differential mobility analyzer/scanning mobility
    particle sizer (TDMA/SMPS) technique. Ammonium nitrate particles 80-220 nm in diameter<...

  3. Aerosol mass spectrometry systems and methods

    DOEpatents

    Fergenson, David P.; Gard, Eric E.

    2013-08-20

    A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

  4. Concentrations, size distributions and temporal variations of fluorescent biological aerosol particles in southern tropical India

    NASA Astrophysics Data System (ADS)

    Valsan, Aswathy; Krishna R, Ravi; CV, Biju; Huffman, Alex; Poschl, Ulrich; Gunthe, Sachin

    2015-04-01

    Biological aerosols constitute a wide range of dead and alive biological materials and structures that are suspended in the atmosphere. They play an important role in the atmospheric physical, chemical and biological processes and health of living being by spread of diseases among humans, plants, and, animals. The atmospheric abundance, sources, physical properties of PBAPs as compared to non-biological aerosols, however, is poorly characterized. The Indian tropical region, where large fraction of the world's total population is residing, experiences a distinctive meteorological phenomenon by means of Indian Summer Monsoon (IMS). Thus, the properties and characteristics of biological aerosols are also expected to be very diverse over the Indian subcontinent depending upon the seasons. Here we characterize the number concentration and size distribution of Fluorescent Biological Aerosol Particles (FBAP) at a high altitude continental site, Munnar (10.09 N, 77.06 E; 1605 m asl) in South India during the South-West monsoon, which constitute around 80 percent of the annual rainfall in Munnar. Continuous three months measurements (from 01 June 2014 to 21 Aug 2104) FBAPs were carried out at Munnar using Ultra Violet Aerodynamic Particle Sizer (UVAPS) during IMS. The mean number and mass concentration of coarse FBAP averaged over the entire campaign was 1.7 x 10-2 cm-3 and 0.24 µg m-3 respectively, which corresponds to 2 percent and 6 percent of total aerosol particle number and mass concentration. In agreement to other previous measurements the number size distribution of FBAP also peaks at 3.2 micron indicating the strong presence of fungal spores. This was also supported by the Scanning Electron Microscopic analysis of bioaerosols on filter paper. They also displayed a strong diurnal cycle with maximum concentration occurring at early morning hours. During periods of heavy and continuous rain where the wind is consistently blowing from South-West direction it was

  5. Fast Airborne Aerosol Size and Chemistry Measurements with the High Resolution Aerosol Mass Spectrometer during the MILAGRO Campaign

    NASA Technical Reports Server (NTRS)

    DeCarlo, P. F.; Dunlea, E. J.; Kimmel, J. R.; Aiken, A. C.; Sueper, D.; Crounse, J.; Wennberg, P. O.; Emmons, L.; Shinozuka, Y.; Clarke, A.; Zhou, J.; Tomlinson, J.; Collins,D. R.; Knapp, D.; Weinheimer, A. J.; Montzka,D. D.; Campos,T.; Jimenez, J. L.

    2007-01-01

    The concentration, size, and composition of non-refractory submicron aerosol (NR-PM(sub l)) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM(sub l) mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 microg/cubic m (STP) ppm(exp -1). This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2008). The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city

  6. Mass spectroscopy of single aerosols from field measurements

    SciTech Connect

    Thomson, D.S.; Murphy, D.M.

    1995-12-31

    We are developing an aircraft instrument for the chemical analysis of individual ambient aerosols in real time. In order to test the laboratory version of this instrument, we participated in a field campaign near the continental divide in Colorado in September, 1993. During this campaign, over 5000 mass spectra of ambient aerosols were collected. Analysis of the negative ion spectra shows that sulfate was the most commonly seen component of smaller particles, while nitrate was more common in larger particles. Organic compounds are present in most particles, and we believe we can distinguish inorganic carbon in some particles. Although numerous distinct classes of particles were observed, indicating external mixtures, almost all of these particle types were themselves mixtures of several compounds. Finally, we note that although the field site experienced distinct polluted and unpolluted episodes, aerosol composition did not correlate with gas phase chemistry.

  7. Black Carbon Concentration from Worldwide Aerosol Robotic Network (AERONET)

    NASA Technical Reports Server (NTRS)

    Schuster, Greg; Dubovik, Oleg; Holben, Brent; Clothiaux, Eugene

    2008-01-01

    Worldwide black carbon concentration measurements are needed to assess the efficacy of the carbon emissions inventory and transport model output. This requires long-term measurements in many regions, as model success in one region or season does not apply to all regions and seasons. AERONET is an automated network of more than 180 surface radiometers located throughout the world. The sky radiance measurements obtained by AERONET are inverted to provide column-averaged aerosol refractive indices and size distributions for the AERONET database, which we use to derive column-averaged black carbon concentrations and specific absorptions that are constrained by the measured radiation field. This provides a link between AERONET sky radiance measurements and the elemental carbon concentration of transport models without the need for an optics module in the transport model. Knowledge of both the black carbon concentration and aerosol absorption optical depth (i.e., input and output of the optics module) will enable improvements to the transport model optics module.

  8. Chemical composition, sources, and processes of urban aerosols during summertime in Northwest China: insights from High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Xu, J.; Zhang, Q.; Chen, M.; Ge, X.; Ren, J.; Qin, D.

    2014-06-01

    An aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed along with a Scanning Mobility Particle Sizer (SMPS) and a Multi Angle Absorption Photometers (MAAP) to measure the temporal variations of the mass loading, chemical composition, and size distribution of sub-micrometer particulate matter (PM1) in Lanzhou, northwest China, during 12 July-7 August 2012. The average PM1 mass concentration including non-refractory PM1 (NR-PM1) measured by HR-ToF-AMS and black carbon (BC) measured by MAAP during this study was 24.5 μg m-3 (ranging from 0.86 to 105μg m-3), with a mean composition consisting of 47% organics, 16% sulfate, 12% BC, 11% ammonium, 10% nitrate, and 4% chloride. The organics was consisted of 70% carbon, 21% oxygen, 8% hydrogen, and 1% nitrogen, with the average oxygen-to-carbon ratio (O / C) of 0.33 and organic mass-to-carbon ratio (OM / OC) of 1.58. Positive matrix factorization (PMF) of the high-resolution mass spectra of organic aerosols (OA) identified four distinct factors which represent, respectively, two primary OA (POA) emission sources (traffic and food cooking) and two secondary OA (SOA) types - a fresher, semi-volatile oxygenated OA (SV-OOA) and a more aged, low-volatility oxygenated OA (LV-OOA). Traffic-related hydrocarbon-like OA (HOA) and BC displayed distinct diurnal patterns both with peak at ~07:00-11:00 (BJT: UTC +8) corresponding to the morning rush hours, while cooking OA (COA) peaked during three meal periods. The diurnal profiles of sulfate and LV-OOA displayed a broad peak between ∼07:00-15:00, while those of nitrate, ammonium, and SV-OOA showed a narrower peak at ~08:00-13:00. The later morning and early afternoon peak in the diurnal profiles of secondary aerosol species was likely caused by mixing down of pollutants aloft, which were likely produced in the residual layer decoupled from the boundary layer during night time. The mass spectrum of SV-OOA also showed similarity with that of

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

    PubMed

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

    2009-03-01

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

  10. Determination of minimum mass and spatial location of initiator for detonation of propylene oxide aerosols

    NASA Astrophysics Data System (ADS)

    Apparao, A.; Saji, J.; Balaji, M.; Devangan, A. K.; Rao, C. R.

    2017-03-01

    The mishandling of liquid fuels during production, processing or transportation can lead to the formation of combustible two-phase mixtures. These mixtures, with the availability of a suitable energy source, may be ignited generating a deflagration, or even a detonation wave. For military applications, unconfined fuel aerosols are created and detonated with the help of a strong shock generated by a powerful energy source. The minimum energy requirement is expressed in terms of the shock strength, or mass of the high-explosive-based initiator. In this study, the detonability of unconfined aerosols of 4.3 kg propylene oxide was studied by positioning different quantities of cylindrical-shaped initiators of RDX/wax (95/5) at a fixed spatial location in the aerosol cloud, and the minimum mass of the initiator required for detonation initiation was determined. The effect of spatial location and the requirement of initiator mass, especially at farther locations where the fuel concentration is likely to be lower and closer to the lower explosive limit, was also investigated. The experimental findings help identify the detonable zone in unconfined propylene oxide aerosol clouds for different combinations of spatial location and mass of initiator.

  11. The link between organic aerosol mass loading and degree of oxygenation: an α-pinene photooxidation study

    NASA Astrophysics Data System (ADS)

    Pfaffenberger, L.; Barmet, P.; Slowik, J. G.; Praplan, A. P.; Dommen, J.; Prévôt, A. S. H.; Baltensperger, U.

    2012-09-01

    A series of smog chamber (SC) experiments was conducted to identify driving factors responsible for the discrepancy between ambient and SC aerosol degree of oxygenation. An Aerodyne high resolution time-of-flight aerosol mass spectrometer is used to compare mass spectra from α-pinene photooxidation with ambient aerosol. Composition is compared in terms of the fraction of organic mass measured at m/z 44 (f44), a surrogate for carboxylic/organic acids as well as the atomic oxygen-to-carbon ratio (O : C), vs. f43, a surrogate for aldehydes, alcohols and ketones. Low (near-ambient) organic mass concentrations were found to be necessary to obtain oxygenation levels similar to those of low-volatility oxygenated organic aerosol (LV-OOA) commonly identified in ambient measurements. The effects of organic mass loading and OH (hydroxyl radical) exposure were decoupled by inter-experiment comparisons at the same integrated OH concentration. On average, an OH exposure of 2.9 ± 1.3 × 107 cm-3 h is needed to increase f44 by 1% during aerosol aging. For the first time, LV-OOA-like aerosol from the abundant biogenic precursor α-pinene was produced in a smog chamber by oxidation at typical atmospheric OH concentrations. Significant correlation between measured secondary organic aerosol (SOA) and reference LV-OOA mass spectra is shown by Pearson's R2 values larger than 0.90 for experiments with low organic mass concentrations between 1.5 and 15 μg m-3 at an OH exposure of 4 × 107 cm-3 h, corresponding to about two days oxidation time in the atmosphere, based on a global mean OH concentration of ∼1 × 106 cm-3. Not only is the α-pinene SOA more oxygenated at low organic mass loadings, but the functional dependence of oxygenation on mass loading is enhanced at atmospherically-relevant precursor concentrations. Since the degree of oxygenation influences the chemical, volatility and hygroscopic properties of ambient aerosol, smog chamber studies must be performed at near

  12. Capstone depleted uranium aerosol biokinetics, concentrations, and doses.

    PubMed

    Guilmette, Raymond A; Miller, Guthrie; Parkhurst, Mary Ann

    2009-03-01

    One of the principal goals of the Capstone Depleted Uranium (DU) Aerosol Study was to quantify and characterize DU aerosols generated inside armored vehicles by perforation with a DU penetrator. This study consequently produced a database in which the DU aerosol source terms were specified both physically and chemically for a variety of penetrator-impact geometries and conditions. These source terms were used to calculate radiation doses and uranium concentrations for various scenarios as part of the Capstone Human Health Risk Assessment (HHRA). This paper describes the scenario-related biokinetics of uranium, and summarizes intakes, chemical concentrations to the organs, and E(50) and HT(50) for organs and tissues based on exposure scenarios for personnel in vehicles at the time of perforation as well as for first responders. For a given exposure scenario (duration time and breathing rates), the range of DU intakes among the target vehicles and shots was not large, about a factor of 10, with the lowest being for a ventilated operational Abrams tank and the highest being for an unventilated Abrams with DU penetrator perforating DU armor. The ranges of committed effective doses were more scenario-dependent than were intakes. For example, the largest range, a factor of 20, was shown for scenario A, a 1 min exposure, whereas, the range was only a factor of two for the first-responder scenario (E). In general, the committed effective doses were found to be in the tens of mSv. The risks ascribed to these doses are discussed separately.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    Receptor modelling was performed on quadrupole unit mass resolution aerosol mass spectrometer (Q-AMS) sub-micron particulate matter (PM) chemical speciation measurements from Windsor, Ontario, an industrial city situated across the Detroit River from Detroit, Michigan. Aerosol and trace gas measurements were collected on board Environment Canada's CRUISER mobile laboratory. Positive matrix factorization (PMF) was performed on the AMS full particle-phase mass spectrum (PMFFull MS) encompassing both organic and inorganic components. This approach was compared to the more common method of analysing only the organic mass spectra (PMFOrg MS). PMF of the full mass spectrum revealed that variability in the non-refractory sub-micron aerosol concentration and composition was best explained by six factors: an amine-containing factor (Amine); an ammonium sulphate and oxygenated organic aerosol containing factor (Sulphate-OA); an ammonium nitrate and oxygenated organic aerosol containing factor (Nitrate-OA); an ammonium chloride containing factor (Chloride); a hydrocarbon-like organic aerosol (HOA) factor; and a moderately oxygenated organic aerosol factor (OOA). PMF of the organic mass spectrum revealed three factors of similar composition to some of those revealed through PMFFull MS: Amine, HOA and OOA. Including both the inorganic and organic mass proved to be a beneficial approach to analysing the unit mass resolution AMS data for several reasons. First, it provided a method for potentially calculating more accurate sub-micron PM mass concentrations, particularly when unusual factors are present, in this case, an Amine factor. As this method does not rely on a priori knowledge of chemical species, it circumvents the need for any adjustments to the traditional AMS species fragmentation patterns to account for atypical species, and can thus lead to more complete factor profiles. It is expected that this method would be even more useful for HR-ToF-AMS data, due to the ability

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    Receptor modeling was performed on quadrupole unit mass resolution aerosol mass spectrometer (Q-AMS) sub-micron particulate matter (PM) chemical speciation measurements from Windsor, Ontario, an industrial city situated across the Detroit River from Detroit, Michigan. Aerosol and trace gas measurements were collected on board Environment Canada's Canadian Regional and Urban Investigation System for Environmental Research (CRUISER) mobile laboratory. Positive matrix factorization (PMF) was performed on the AMS full particle-phase mass spectrum (PMFFull MS) encompassing both organic and inorganic components. This approach compared to the more common method of analyzing only the organic mass spectra (PMFOrg MS). PMF of the full mass spectrum revealed that variability in the non-refractory sub-micron aerosol concentration and composition was best explained by six factors: an amine-containing factor (Amine); an ammonium sulfate- and oxygenated organic aerosol-containing factor (Sulfate-OA); an ammonium nitrate- and oxygenated organic aerosol-containing factor (Nitrate-OA); an ammonium chloride-containing factor (Chloride); a hydrocarbon-like organic aerosol (HOA) factor; and a moderately oxygenated organic aerosol factor (OOA). PMF of the organic mass spectrum revealed three factors of similar composition to some of those revealed through PMFFull MS: Amine, HOA and OOA. Including both the inorganic and organic mass proved to be a beneficial approach to analyzing the unit mass resolution AMS data for several reasons. First, it provided a method for potentially calculating more accurate sub-micron PM mass concentrations, particularly when unusual factors are present, in this case the Amine factor. As this method does not rely on a priori knowledge of chemical species, it circumvents the need for any adjustments to the traditional AMS species fragmentation patterns to account for atypical species, and can thus lead to more complete factor profiles. It is expected that this

  15. The effect of sea ice loss on sea salt aerosol concentrations and the radiative balance in the Arctic

    NASA Astrophysics Data System (ADS)

    Struthers, H.; Ekman, A. M. L.; Glantz, P.; Iversen, T.; Kirkevåg, A.; Mårtensson, E. M.; Seland, Ø.; Nilsson, E. D.

    2011-04-01

    Understanding Arctic climate change requires knowledge of both the external and the local drivers of Arctic climate as well as local feedbacks within the system. An Arctic feedback mechanism relating changes in sea ice extent to an alteration of the emission of sea salt aerosol and the consequent change in radiative balance is examined. A set of idealized climate model simulations were performed to quantify the radiative effects of changes in sea salt aerosol emissions induced by prescribed changes in sea ice extent. The model was forced using sea ice concentrations consistent with present day conditions and projections of sea ice extent for 2100. Sea salt aerosol emissions increase in response to a decrease in sea ice, the model results showing an annual average increase in number emission over the polar cap (70-90° N) of 86 × 106 m-2 s-1 (mass emission increase of 23 μg m-2 s-1). This in turn leads to an increase in the natural aerosol optical depth of approximately 23%. In response to changes in aerosol optical depth, the natural component of the aerosol direct forcing over the Arctic polar cap is estimated to be between -0.2 and -0.4 W m-2 for the summer months, which results in a negative feedback on the system. The model predicts that the change in first indirect aerosol effect (cloud albedo effect) is approximately a factor of ten greater than the change in direct aerosol forcing although this result is highly uncertain due to the crude representation of Arctic clouds and aerosol-cloud interactions in the model. This study shows that both the natural aerosol direct and first indirect effects are strongly dependent on the surface albedo, highlighting the strong coupling between sea ice, aerosols, Arctic clouds and their radiative effects.

  16. Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3 aerosol during the 2013 Southern Oxidant and Aerosol Study

    SciTech Connect

    Allen, H. M.; Draper, D. C.; Ayres, B. R.; Ault, A.; Bondy, A.; Takahama, S.; Modini, R. L.; Baumann, K.; Edgerton, E.; Knote, C.; Laskin, A.; Wang, B.; Fry, J. L.

    2015-09-25

    Inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two periods of high aerosol nitrate (NO3) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of supermicron crustal and sea spray aerosol species, particularly Na+ and Ca2+, and with a shift towards aerosol with larger (1 to 2.5 μm) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO3 and particles, reactions that are facilitated by transport of crustal dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH4NO3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. In addition, calculation of the rate of the heterogeneous uptake of HNO3 on mineral aerosol supports the conclusion that aerosol NO3 is produced primarily by this process, and is likely limited by the availability of mineral cation-containing aerosol surface area. Modeling of NO3 and HNO3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas–aerosol phase partitioning.

  17. A comparison of secondary organic aerosol (SOA) yields and composition from ozonolysis of monoterpenes at varying concentrations of NO2

    NASA Astrophysics Data System (ADS)

    Draper, D. C.; Farmer, D. K.; Desyaterik, Y.; Fry, J. L.

    2015-05-01

    The effect of NO2 on secondary organic aerosol (SOA) formation from ozonolysis of α-pinene, β-pinene, Δ3-carene, and limonene was investigated using a dark flow-through reaction chamber. SOA mass yields were calculated for each monoterpene from ozonolysis with varying NO2 concentrations. Kinetics modeling of the first generation gas-phase chemistry suggests that differences in observed aerosol yields for different NO2 concentrations are consistent with NO3 formation and subsequent competition between O3 and NO3 to oxidize each monoterpene. α-pinene was the only monoterpene studied that showed a systematic decrease in both aerosol number concentration and mass concentration with increasing [NO2]. β-pinene and Δ3-carene produced fewer particles at higher [NO2], but both retained moderate mass yields. Limonene exhibited both higher number concentrations and greater mass concentrations at higher [NO2]. SOA from each experiment was collected and analyzed by HPLC-ESI-MS, enabling comparisons between product distributions for each system. In general, the systems influenced by NO3 oxidation contained more high molecular weight products (MW >400 amu), suggesting the importance of oligomerization mechanisms in NO3-initiated SOA formation. α-pinene, which showed anomalously low aerosol mass yields in the presence of NO2, showed no increase in these oligomer peaks, suggesting that lack of oligomer formation is a likely cause of α-pinene's near 0% yields with NO3. Through direct comparisons of mixed-oxidant systems, this work suggests that NO3 is likely to dominate nighttime oxidation pathways in most regions with both biogenic and anthropogenic influences. Therefore, accurately constraining SOA yields from NO3 oxidation, which vary substantially with the VOC precursor, is essential in predicting nighttime aerosol production.

  18. A qualitative comparison of secondary organic aerosol yields and composition from ozonolysis of monoterpenes at varying concentrations of NO2

    NASA Astrophysics Data System (ADS)

    Draper, D. C.; Farmer, D. K.; Desyaterik, Y.; Fry, J. L.

    2015-11-01

    The effect of NO2 on secondary organic aerosol (SOA) formation from ozonolysis of α-pinene, β-pinene, Δ3-carene, and limonene was investigated using a dark flow-through reaction chamber. SOA mass yields were calculated for each monoterpene from ozonolysis with varying NO2 concentrations. Kinetics modeling of the first-generation gas-phase chemistry suggests that differences in observed aerosol yields for different NO2 concentrations are consistent with NO3 formation and subsequent competition between O3 and NO3 to oxidize each monoterpene. α-Pinene was the only monoterpene studied that showed a systematic decrease in both aerosol number concentration and mass concentration with increasing [NO2]. β-Pinene and Δ3-carene produced fewer particles at higher [NO2], but both retained moderate mass yields. Limonene exhibited both higher number concentrations and greater mass concentrations at higher [NO2]. SOA from each experiment was collected and analyzed by HPLC-ESI-MS, enabling comparisons between product distributions for each system. In general, the systems influenced by NO3 oxidation contained more high molecular weight products (MW > 400 amu), suggesting the importance of oligomerization mechanisms in NO3-initiated SOA formation. α-Pinene, which showed anomalously low aerosol mass yields in the presence of NO2, showed no increase in these oligomer peaks, suggesting that lack of oligomer formation is a likely cause of α-pinene's near 0 % yields with NO3. Through direct comparisons of mixed-oxidant systems, this work suggests that NO3 is likely to dominate nighttime oxidation pathways in most regions with both biogenic and anthropogenic influences. Therefore, accurately constraining SOA yields from NO3 oxidation, which vary substantially with the volatile organic compound precursor, is essential in predicting nighttime aerosol production.

  19. Identification and Characterization of Biogenic SOA Component in Ambient Aerosols Based on Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Jimenez, J.; Allan, J. D.; Kiendler-Scharr, A.; Tian, J.; Canagaratna, M. R.; Williams, B.; Worsnop, D. R.; Coe, H.; Goldstein, A.; Mentel, T. F.

    2008-12-01

    Recently studies have shown that multivariate factor analysis of the highly time-resolved mass spectral data obtained with an Aerodyne Aerosol Mass Spectrometer (AMS) may allow the classification and simplification of complex organic aerosol (OA) mixtures into components that are chemically meaningful and can be related to different sources and transformation processes. Two factor analysis techniques, including the Multiple Component Analysis (MCA) method (Zhang et al., 2007) and the Positive Matrix Factorization (PMF) method (Paatero and Tapper, 1994), were applied to a Quadrupole-AMS dataset acquired from Chebogue Pt., Nova Scotia in summer 2004. Multiple OA components were determined, including a hydrocarbon-like OA (HOA) component similar in mass spectra to the hydrocarbon substances observed at urban locations and two oxygenated OA (OA) components that show different fragmentation patterns and oxygen-to-carbon ratios in their mass spectra. The HOA component correlates with inert primary emission tracers (e.g., EC and CO) and likely represents diluted POA transported from urban locations. The highly oxygenated component (OOA-I) correlates well with sulfate and shows a mass spectrum resembling that of fulvic acid - a model compound representative for highly processed/oxidized organics in the environment. The less oxygenated OA component (OOA-II) reveals a mass spectral pattern that compares well with those of the biogenic SOA produced from the mixture of VOCs emitted by spruce, pine and birch trees during exposure to ozone and UV-photolysis in the Jülich plant chamber. In addition, the time series of OOA-II correlates with biogenic SOA tracer compounds determined by the thermal desorption aerosol GC/MS-FID (TAG) instrument. Furthermore, the time-resolved size distributions of OOA components, their correlations with parallel gas and aerosol measurements, and backtrajectory analysis of air masses all support the association of OOA-II to biogenic sources. Finally

  20. Ambient aerosol concentrations of sugars and sugar-alcohols at four different sites in Norway

    NASA Astrophysics Data System (ADS)

    Yttri, K. E.; Dye, C.; Kiss, G.

    2007-08-01

    Sugars and sugar-alcohols are demonstrated to be important constituents of the ambient aerosol water-soluble organic carbon fraction, and to be tracers for primary biological aerosol particles (PBAP). In the present study, levels of four sugars (fructose, glucose, sucrose, trehalose) and three sugar-alcohols (arabitol, inositol, mannitol) in ambient aerosols have been quantified using a novel HPLC/HRMS-TOF (High Performance Liquid Chromatography in combination with High Resolution Mass Spectrometry - Time of Flight) method to assess the contribution of PBAP to PM>sub>10 and PM2.5. Samples were collected at four sites in Norway at different times of the year in order to reflect the various contributing sources and the spatial and seasonal variation of the selected compounds. Sugars and sugar-alcohols were present at all sites investigated, underlining the ubiquity of these highly polar organic compounds. The highest concentrations were reported for sucrose, reaching a maximum concentration of 320 ng m-3 in PM10 and 55 ng m-3 in PM2.5. The mean concentration of sucrose was up to 10 times higher than fructose, glucose and the dimeric sugar trehalose. The mean concentrations of the sugar-alcohols were typically lower, or equal, to that of the monomeric sugars and trehalose. Peak concentrations of arabitol and mannitol did not exceed 30 ng m-3 in PM10, and for PM2.5 all concentrations were below 6 ng m-3. Sugars and sugar-alcohols were associated primarily with coarse aerosols except during wintertime at the suburban site in Elverum, where a shift towards sub micron aerosols was observed. It is proposed that this shift was due to the intensive use of wood burning for residential heating at this site during winter, confirmed by high concurrent concentrations of levoglucosan. Elevated concentrations of sugars in PM2.5 were observed during spring and early summer at the rural background site Birkenes. It is hypothesized that this was due to ruptured pollen.

  1. Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Harrison, R. M.

    2012-05-01

    During the month of October 2006, as part of the REPARTEE-I experiment (Regent's Park and Tower Environmental Experiment) an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed at an urban background location in the city of London, UK. Fifteen particle types were classified, some of which were already discussed (Dall'Osto et al., 2009a,b; Harrison et al., 2012). In this manuscript the origins and properties of four unreported particle types postulated to be due to locally generated aerosols, independent of the air mass type advected into London, are examined. One particle type, originating from lubricating oil (referred to as Ca-EC), was associated with morning rush hour traffic emissions. A second particle type, composed of both inorganic and organic species (called Na-EC-OC), was found enhanced in particle number concentration during evening time periods, and is likely to originate from a source operating at this time of day, or more probably from condensation of semi-volatile species. A third class, internally mixed with organic carbon and sulphate (called OC), was found to spike both in the morning and evenings although it could not unambiguously associated with a specific source or atmospheric process. The fourth class (Secondary Organic Aerosols - Polycyclic Aromatic Hydrocarbon; SOA-PAH) exhibited maximum frequency during the warmest part of the day, and a number of factors point towards secondary aerosol production from traffic-related volatile aromatic compounds. Single particle mass spectra of this particle type showed an oxidized polycyclic aromatic compound signature. A comparison of ATOFMS particle class data is then made with factors obtained by Positive Matrix Factorization and PAH signatures obtained from Aerosol Mass Spectrometer (AMS) data (Allan et al., 2010). Both the Ca-EC and OC particle types correlate with primary Hydrocarbon-like Organic Aerosol (HOA, R2 = 0.65 and 0.50 respectively), and Na-EC-OC correlates weakly with the AMS

  2. Characterization of Ambient Aerosols in Mexico City during the MCMA-2003 Campaign with Aerosol Mass Spectrometry. Results from the CENICA Supersite

    SciTech Connect

    Salcedo, D; Onasch, Timothy B; Dzepina, K; Canagaratna, M R; Zhang, Q; Huffman, A J; DeCarlo, Peter; Jayne, J T; Mortimer, P; Worsnop, Douglas R; Kolb, C E; Johnson, Kirsten S; Zuberi, Bilal M; Marr, L; Volkamer, Rainer M; Molina, Luisa; Molina, Mario J; Cardenas, B; Bernabe, R; Marquez, C; Gaffney, Jeffrey S; Marley, Nancy A; Laskin, Alexander; Shutthanandan, V; Xie, YuLong; Brune, W H; Lesher, R; Shirley, T; Jiminez, J L

    2006-03-24

    An Aerodyne Aerosol Mass Spectrometer (AMS) was deployed at the CENICA Supersite, while another was deployed in the Aerodyne Mobile Laboratory (AML) during the Mexico City Metropolitan Area field study (MCMA-2003) from March 29-May 4, 2003 to investigate particle concentrations, sources, and processes. This is the first of a series of papers reporting the AMS results from this campaign. The AMS provides real time information on mass concentration and composition of the non-refractory species in particulate matter less than 1 μm (NR PM1) with high time and size resolution. For the first time, we report field results from a beam width probe, which was used to study the shape and mixing state of the particles and to quantify potential losses of irregular particles due to beam broadening inside the AMS. Data from this probe show that no significant amount of irregular particles was lost due to excessive beam broadening. A comparison of the CENICA and AML AMSs measurements is presented, being the first published intercomparison between two quadrupole AMSs. The speciation, and mass concentrations reported by the two AMSs compared well. In order to account for the refractory material in the aerosol, we also present measurements of Black Carbon (BC) using an aethalometer and an estimate of the aerosol soil component obtained from PIXE analysis of filters. Comparisons of (AMS + BC + soil) mass concentration with other collocated particle instruments (a LASAIR Optical Particle Counter, a Tapered Element Oscillating Microbalance (TEOM) and a DustTrack Aerosol Monitor) are also presented. The comparisons show that the (AMS + BC + soil) mass concentration during MCMC-2003 is a good approximation to the total PM₂.₅ mass concentration.

  3. Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Daellenbach, K. R.; Bozzetti, C.; Křepelová, A.; Canonaco, F.; Wolf, R.; Zotter, P.; Fermo, P.; Crippa, M.; Slowik, J. G.; Sosedova, Y.; Zhang, Y.; Huang, R.-J.; Poulain, L.; Szidat, S.; Baltensperger, U.; Prévôt, A. S. H.; El Haddad, I.

    2015-08-01

    Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS) have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make impractical its deployment at sufficient sites to determine regional characteristics. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM) filter samples (PM1, PM2.5, PM10) collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g. AMS or Aerosol Chemical Speciation Monitor (ACSM). The bulk recoveries of organic aerosol (60-91 %) achieved using this technique, together with low detection limits (0.8 μg of organic aerosol on the analyzed filter fraction) allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon, oxygen containing and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g. filter artifacts and limited time resolution) may be used to enhance the AMS capabilities in measuring size-fractionated, spatially-resolved long-term datasets.

  4. Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Daellenbach, K. R.; Bozzetti, C.; Křepelová, A.; Canonaco, F.; Wolf, R.; Zotter, P.; Fermo, P.; Crippa, M.; Slowik, J. G.; Sosedova, Y.; Zhang, Y.; Huang, R.-J.; Poulain, L.; Szidat, S.; Baltensperger, U.; El Haddad, I.; Prévôt, A. S. H.

    2016-01-01

    Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS) have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make its deployment at sufficient sites to determine regional characteristics impractical. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM) filter samples (PM1, PM2.5, and PM10, i.e., PM with aerodynamic diameters smaller than 1, 2.5, and 10 µm, respectively), collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g., AMS or Aerosol Chemical Speciation Monitor (ACSM). The bulk recoveries of organic aerosol (60-91 %) achieved using this technique, together with low detection limits (0.8 µg of organic aerosol on the analyzed filter fraction) allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon ions, ions containing oxygen, and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning, and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g., filter artifacts and limited time resolution) may be used to enhance the AMS capabilities in measuring size-fractionated, spatially resolved long-term data sets.

  5. The link between organic aerosol mass loading and degree of oxygenation: an α-pinene photooxidation study

    NASA Astrophysics Data System (ADS)

    Pfaffenberger, L.; Barmet, P.; Slowik, J. G.; Praplan, A. P.; Dommen, J.; Prévôt, A. S. H.; Baltensperger, U.

    2013-07-01

    A series of smog chamber (SC) experiments was conducted to identify factors responsible for the discrepancy between ambient and SC aerosol degree of oxygenation. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer is used to compare mass spectra from α-pinene photooxidation with ambient aerosol. Composition is compared in terms of the fraction of particulate CO2+, a surrogate for carboxylic acids, vs. the fraction of C2H3O+, a surrogate for aldehydes, alcohols and ketones, as well as in the Van Krevelen space, where the evolution of the atomic hydrogen-to-carbon ratio (H : C) vs. the atomic oxygen-to-carbon ratio (O : C) is investigated. Low (near-ambient) organic mass concentrations were found to be necessary to obtain oxygenation levels similar to those of low-volatility oxygenated organic aerosol (LV-OOA) commonly identified in ambient measurements. The effects of organic mass loading and OH (hydroxyl radical) exposure were decoupled by inter-experiment comparisons at the same integrated OH concentration. An OH exposure between 3 and 25 × 107 cm-3 h is needed to increase O : C by 0.05 during aerosol aging. For the first time, LV-OOA-like aerosol from the abundant biogenic precursor α-pinene was produced in a smog chamber by oxidation at typical atmospheric OH concentrations. Significant correlation between measured secondary organic aerosol (SOA) and reference LV-OOA mass spectra is shown by Pearson's R2 values larger than 0.90 for experiments with low organic mass concentrations between 1.2 and 18 μg m-3 at an OH exposure of 4 × 107 cm-3 h, corresponding to about two days of oxidation time in the atmosphere, based on a global mean OH concentration of ~ 1 × 106 cm-3. α-Pinene SOA is more oxygenated at low organic mass loadings. Because the degree of oxygenation influences the chemical, volatility and hygroscopic properties of ambient aerosol, smog chamber studies must be performed at near-ambient concentrations to accurately simulate

  6. Fungal Spore Concentrations and Ergosterol Content in Aerosol Samples in the Caribbean During African Dust Events

    NASA Astrophysics Data System (ADS)

    Santos-Figueroa, G.; Bolaños-Rosero, B.; Mayol-Bracero, O. L.

    2015-12-01

    Fungal spores are a major component of primary biogenic aerosol particles that are emitted to the atmosphere, are ubiquitous, and play an important role in the chemistry and physics of the atmosphere, climate, and public health. Every year, during summer months, African dust (AD) particles are transported to the Caribbean region causing an increase in the concentrations of particulate matter in the atmosphere. AD is one of the most important natural sources of mineral particulate matter at the global scale, and many investigations suggest that it has the ability to transport dust-associated biological particles through long distances. The relationship between AD incursions and the concentration of fungal spores in the Caribbean region is poorly understood. In order to investigate the effects of AD incursions on fungal spore's emissions, fungal spore concentrations were monitored using a Burkard spore trap at the tropical montane cloud forest of Pico del Este at El Yunque National Forest, Puerto Rico. The presence of AD was supported with satellite images of aerosol optical thickness, and with the results from the air masses backward trajectories calculated with the NOAA HYSPLIT model. Basidiospores and Ascospores comprised the major components of the total spore's concentrations, up to a maximum of 98%, during both AD incursions and background days. A considerably decrease in the concentration of fungal spores during AD events was observed. Ergosterol, biomarker for measuring fungal biomass, concentrations were determined in aerosols that were sampled at a marine site, Cabezas de San Juan Nature Reserve, in Fajardo Puerto Rico, and at an urban site, Facundo Bueso building at the University of Puerto Rico. Additional efforts to understand the relationship between the arrival of AD to the Caribbean and a decrease in spore's concentrations are needed in order to investigate changes in local spore's vs the contribution of long-range spores transported within the AD.

  7. Characterization of aerosol composition and sources in the greater Atlanta area by aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Ng, N. L.; Xu, L.; Suresh, S.; Weber, R. J. J.; Baumann, K.; Edgerton, E. S.

    2014-12-01

    An important and uncertain aspect of biogenic secondary organic aerosol (SOA) formation is that it is often associated with anthropogenic pollution tracers. Prior studies in Atlanta suggested that 70-80% of the carbon in water-soluble organic carbon (WSOC) is modern, yet it is well-correlated with the anthropogenic CO. In this study, we deployed a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) at multiple sites in different seasons (May 2012-February 2013) to characterize the sources and chemical composition of aerosols in the greater Atlanta area. This area in the SE US is ideal to investigate anthropogenic-biogenic interactions due to high natural and anthropogenic emissions. These extensive field studies are part of the Southeastern Center for Air Pollution and Epidemiology study (SCAPE). The HR-ToF-AMS is deployed at four sites (~ 3 weeks each) in rotation: Jefferson Street (urban), Yorkville (rural), roadside site (near Highway 75/85), and Georgia Tech site (campus), with the urban and rural sites being part of the SEARCH network. We obtained seven HR-ToF-AMS datasets in total. During the entire measurement period, the ACSM is stationary at the GIT site and samples continuously. We perform positive matrix factorization (PMF) analysis on the HR-ToF-AMS and ACSM data to deconvolve the OA into different components. While the diurnal cycle of the total OA is flat as what have been previously observed, the OA factors resolved by PMF analysis show distinctively different diurnal trends. We find that the "more-oxidized oxygenated OA" (MO-OOA) constitutes a major fraction of OA at all sites. In summer, OA is dominated by SOA, e.g., isoprene-OA and OOA with different degrees of oxidation. In contrary, biomass burning OA is more prominent in winter data. By comparing HR-ToF-AMS and ACSM data during the same sampling periods, we find that the aerosol time series are highly correlated, indicating the

  8. Mass Spectrometry of Atmospheric Aerosol: 1 nanometer to 1 micron

    NASA Astrophysics Data System (ADS)

    Worsnop, D. R.; Ehn, M.; Junninen, H.; Kulmala, M. T.

    2010-12-01

    The role of aerosol particles remains the largest uncertainty in quantitatively assessing past, current and future climate change. The principal reason for that uncertainty arises from the need to characterize and model composition and size dependent aerosol processes, ranging from nanometer to micron scales. Aerosol mass spectrometry results have shown that about half the sub-micron aerosol composition is composed of highly oxygenated organics that are not well understood in terms of photochemical reaction mechanisms (Jimenez et al, 2009). This work has included application of high resolution time-of-flight mass spectrometry (ToFMS) in order to determine elemental and functional group composition of complex organic components. Recently, we have applied similar ToFMS to determine the composition of ambient ions, molecules and clusters, potentially involved in formation and growth of nano-particles (Junninen et al, 2010). Observed organic anions (molecular weight range 200-500 Th) have similar chemical composition as the least volatile secondary organics observed in fine particles; while organic cations are dominated by amines and pyridines. During nucleation events, anions are dominated by sulphuric acid cluster ions (Ehn et al, 2010). In both nanometer and micrometer size ranges, the goal to elucidate the roles of inorganic and organic species, particularly how particle evolution and physical properties depend on mixed compositions. Recent results will be discussed, including ambient and experimental chamber observations. Ehn et al, Atmos. Chem. Phys. Discuss., 10, 14897-14946, 2010 Jimenez et al, Science, 326, 1525-1529, 2009 Junninen et al, Atmos. Meas. Tech., 3, 1039-1053, 2010

  9. Influence of the Surf Zone on the Marine Aerosol Concentration in a Coastal Area

    NASA Astrophysics Data System (ADS)

    Tedeschi, Gilles; van Eijk, Alexander M. J.; Piazzola, Jacques; Kusmierczyk-Michulec, Jolanta T.

    2017-01-01

    Sea-salt aerosol concentrations in the coastal zone are assessed with the numerical aerosol-transport model MACMod that applies separate aerosol source functions for open ocean and the surf zone near the sea-land transition. Numerical simulations of the aerosol concentration as a function of offshore distance from the surf zone compare favourably with experimental data obtained during a surf-zone aerosol experiment in Duck, North Carolina in autumn 2007. Based on numerical simulations, the effect of variations in aerosol production (source strength) and transport conditions (wind speed, air-sea temperature difference), we show that the surf-zone aerosols are replaced by aerosols generated over the open ocean as the airmass advects out to sea. The contribution from the surf-generated aerosol is significant during high wind speeds and high wave events, and is significant up to 30 km away from the production zone. At low wind speeds, the oceanic component dominates, except within 1-5 km of the surf zone. Similar results are obtained for onshore flow, where no further sea-salt aerosol production occurs as the airmass advects out over land. The oceanic aerosols that are well-mixed throughout the boundary layer are then more efficiently transported inland than are the surf-generated aerosols, which are confined to the first few tens of metres above the surface, and are therefore also more susceptible to the type of surface (trees or grass) that determines the deposition velocity.

  10. Daily concentration variations of nitrate in the atmospheric aerosols voer Sakai, Japan

    SciTech Connect

    Mizohata, Akira; Ito, Norio

    1996-12-31

    Atmospheric aerosols have been sampled on a quartz fiber filter on a daily basis in Sakai, Japan since 1986. The obtained filter samples were extracted with distilled water, and ionic species concentrations were quantitatively determined by using ion chromatography. In this paper study of the nitrate concentration was described. Analysis showed that the mean concentration for period January 1986 to December 1993 was 2.4 {mu}g/m{sup 3}. Monthly mean was in the range of 0.9 to 3.9 {mu}g/m{sup 3}, and highest in April and lowest in August. Especially the concentrations for period March to June 1991 were remarkably high because of the Kuwait oil well fire due to the Gulf War. Annual mean was increasing over a long period of time. Explaining this trend and the seasonal variations, we considered air mass trajectories.

  11. 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.

  12. 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

  13. Aerosols in polluted versus nonpolluted air masses Long-range transport and effects on clouds

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Van Valin, C. C.; Castillo, R. C.; Kadlecek, J. A.; Ganor, E.

    1986-01-01

    To assess the influence of anthropogenic aerosols on the physics and chemistry of clouds in the northeastern United States, aerosol and cloud-drop size distributions, elemental composition of aerosols as a function of size, and ionic content of cloud water were measured on Whiteface Mountain, NY, during the summers of 1981 and 1982. In several case studies, the data were cross-correlated with different air mass types - background continental, polluted continental, and maritime - that were advected to the sampling site. The results are the following: (1) Anthropogenic sources hundreds of kilometers upwind cause the small-particle (accumulation) mode number to increase from hundreds of thousands per cubic centimeter and the mass loading to increase from a few to several tens of micrograms per cubic meter, mostly in the form of sulfur aerosols. (2) A significant fraction of anthropogenic sulfur appears to act as cloud condensation nuclei (CCN) to affect the cloud drop concentration. (3) Clouds in Atlantic maritime air masses have cloud drop spectra that are markedly different from those measured in continental clouds. The drop concentration is significantly lower, and the drop size spectra are heavily skewed toward large drops. (4) Effects of anthropogenic pollutants on cloud water ionic composition are an increase of nitrate by a factor of 50, an increase of sulfate by more than one order of magnitude, and an increase of ammonium ion by a factor of 7. The net effect of the changes in ionic concentrations is an increase in cloud water acidity. An anion deficit even in maritime clouds suggests an unknown, possibly biogenic, source that could be responsible for a pH below neutral, which is frequently observed in nonpolluted clouds.

  14. Oscillations of a String with Concentrated Masses

    ERIC Educational Resources Information Center

    Gomez, B. J.; Repetto, C. E.; Stia, C. R.; Welti, R.

    2007-01-01

    In this work, the oscillations of a homogeneous string fixed at both ends, and loaded with a finite number of masses, are studied. Through a simple device, the cases with one and two concentrated masses are analysed in detail. The normal modes are observed and the corresponding frequencies are recorded. The experimental results and the solutions…

  15. Direct evaluation of aerosol-mass loadings from multispectral extinction data

    NASA Technical Reports Server (NTRS)

    Box, M. A.; Mckellar, B. H. J.

    1978-01-01

    A formula is derived for the evaluation of the total volume of aerosol in a column, and hence for the aerosol columnar mass loading, from multispectral extinction data. This formula is exact in the 'anomalous diffraction' approximation, and reasonably accurate for Mie scattering, over a fairly wide range of refractive indices typical of real aerosols.

  16. Effect of aerosol number concentration on cloud droplet dispersion: An LES study and implications for aerosol indirect forcing

    NASA Astrophysics Data System (ADS)

    Lu, M.; Seinfeld, J. H.

    2005-12-01

    Through three-dimensional LES simulations of marine stratocumulus we explore the factors that control the cloud spectral relative dispersion (ratio of cloud droplet spectral width to the mean radius of the distribution) as a function of aerosol number concentration and the extent to which the relative dispersion either enhances or mitigates the Twomey effect. We find that relative dispersion decreases with increasing aerosol number concentration (for aerosol number concentrations less than about 1000 cm- 3) because smaller droplets resulting from higher aerosol number concentrations inhibit precipitation and lead to: (1) less spectral broadening by suppressed collision and coalescence processes; and (2) more spectral narrowing by droplet condensational growth at higher updraft velocity, because reduced drizzle latent heating at cloud top results in increased boundary layer turbulent kinetic energy production by buoyancy and thereby stronger turbulence. Increased spectral broadening owing to increased cloud-top entrainment mixing, also as a result of increased boundary layer turbulence, is relatively insignificant compared with (1) and (2). The coefficient k, an important parameter that relates cloud droplet effective radius and volume mean radius in large-scale models, is a function of skewness and relative dispersion of the distribution and is negatively correlated with relative dispersion. Increasing k with increasing aerosol number concentration leads to maximum enhancement of the cloud susceptibility (the change of cloud optical depth due to change of cloud droplet number concentration) over that attributable to the Twomey effect alone by about 4.2% and 39% for simulated FIRE and ASTEX cases, respectively.

  17. Impacts of Wet Scavenging Parameterizations on Global Simulations of Aerosol Concentrations and Lifetimes (Invited)

    NASA Astrophysics Data System (ADS)

    Croft, B.; Martin, R.; Lohmann, U.; Pierce, J. R.

    2013-12-01

    Wet scavenging processes strongly control aerosol three-dimensional distributions. In this study, we quantify the uncertainty in global simulations of aerosol vertical profiles and lifetimes, which may be attributed to uncertainties in both convective and stratiform wet scavenging parameterizations. For convective clouds, we show that different assumptions about the wet removal of aerosols entrained above convective cloud bases can yield differences of about one order of magnitude in middle and upper tropospheric aerosol concentrations. For stratiform clouds, we demonstrate the impact of size-dependent aerosol wet scavenging as compared to the use of fixed prescribed scavenging coefficients. We quantify the difference in simulated aerosol concentrations, particularly at high latitudes, yielded by different assumptions about scavenging in mixed phase and ice clouds. We also examine the sensitivity of simulated global mean aerosol lifetimes to parameterizations for wet scavenging. Global simulations of the scavenging of aerosol-bound radionuclides following the Fukushima Dai-Ichi nuclear power plant accident are also presented. The simulated radionuclide lifetimes are compared to measurements. We present an interpretation of these constraints on global mean aerosol lifetimes. The sensitivity of simulated aerosol-bound radionuclide lifetimes to altitude and location of the radionuclide injection is also examined with consideration to the interplay of aerosol transport, mixing, and removal processes.

  18. Investigation of the seasonal variations of aerosol physicochemical properties and their impact on cloud condensation nuclei number concentration

    NASA Astrophysics Data System (ADS)

    Logan, Timothy S.

    Aerosols are among the most complex yet widely studied components of the atmosphere not only due to the seasonal variability of their physical and chemical properties but also their effects on climate change. The three main aerosol types that are known to affect the physics and chemistry of the atmosphere are: mineral dust, anthropogenic pollution, and biomass burning aerosols. In order to understand how these aerosols affect the atmosphere, this dissertation addresses the following three scientific questions through a combination of surface and satellite observations: SQ1: What are the seasonal and regional variations of aerosol physico-chemical properties at four selected Asian sites? SQ2: How do these aerosol properties change during transpacific and intra-continental long range transport? SQ3: What are the impacts of aerosol properties on marine boundary layer cloud condensation nuclei number concentration? This dissertation uses an innovative approach to classify aerosol properties by region and season to address SQ1. This is useful because this method provides an additional dimension when investigating the physico-chemical properties of aerosols by linking a regional and seasonal dependence to both the aerosol direct and indirect effects. This method involves isolating the aerosol physico-chemical properties into four separate regions using AERONET retrieved Angstrom exponent (AEAOD) and single scattering co-albedo (o oabs) to denote aerosol size and absorptive properties. The aerosols events are then clustered by season. The method is first applied to four AERONET sites representing single mode aerosol dominant regions: weakly absorbing pollution (NASA Goddard), strongly absorbing pollution (Mexico City), mineral dust (Solar Village), and biomass burning smoke (Alta Floresta). The method is then applied to four Asian sites that represent complicated aerosol components. There are strong regional and seasonal influences of the four aerosol types over the

  19. Mass absorption indices of various types of natural aerosol particles in the infrared.

    PubMed

    Fischer, K

    1975-12-01

    The mass absorption index of aerosol particles has been measured in the 2-17-microm wavelength region. The measurements were performed on films of aerosol particles that were collected by an automatic jet impactor at polluted and various uncontaminated remote sites. All but marine aerosols possess strong absorption bands in the transparent part of the atmospheric long-wave spectrum, indicating marked influence of aerosol particles on the radiation budget of the atmosphere.

  20. Organosulfates and organic acids in Arctic aerosols: speciation, annual variation and concentration levels

    NASA Astrophysics Data System (ADS)

    Hansen, A. M. K.; Kristensen, K.; Nguyen, Q. T.; Zare, A.; Cozzi, F.; Nøjgaard, J. K.; Skov, H.; Brandt, J.; Christensen, J. H.; Ström, J.; Tunved, P.; Krejci, R.; Glasius, M.

    2014-08-01

    Sources, composition and occurrence of secondary organic aerosols in the Arctic were investigated at Zeppelin Mountain, Svalbard, and Station Nord, northeastern Greenland, during the full annual cycle of 2008 and 2010, respectively. Speciation of organic acids, organosulfates and nitrooxy organosulfates - from both anthropogenic and biogenic precursors were in focus. A total of 11 organic acids (terpenylic acid, benzoic acid, phthalic acid, pinic acid, suberic acid, azelaic acid, adipic acid, pimelic acid, pinonic acid, diaterpenylic acid acetate and 3-methyl-1,2,3-butanetricarboxylic acid), 12 organosulfates and 1 nitrooxy organosulfate were identified in aerosol samples from the two sites using a high-performance liquid chromatograph (HPLC) coupled to a quadrupole Time-of-Flight mass spectrometer. At Station Nord, compound concentrations followed a distinct annual pattern, where high mean concentrations of organosulfates (47 ± 14 ng m-3) and organic acids (11.5 ± 4 ng m-3) were observed in January, February and March, contrary to considerably lower mean concentrations of organosulfates (2 ± 3 ng m-3) and organic acids (2.2 ± 1 ng m-3) observed during the rest of the year. At Zeppelin Mountain, organosulfate and organic acid concentrations remained relatively constant during most of the year at a mean concentration of 15 ± 4 ng m-3 and 3.9 ± 1 ng m-3, respectively. However during four weeks of spring, remarkably higher concentrations of total organosulfates (23-36 ng m-3) and total organic acids (7-10 ng m-3) were observed. Elevated organosulfate and organic acid concentrations coincided with the Arctic haze period at both stations, where northern Eurasia was identified as the main source region. Air mass transport from northern Eurasia to Zeppelin Mountain was associated with a 100% increase in the number of detected organosulfate species compared with periods of air mass transport from the Arctic Ocean, Scandinavia and Greenland. The results from this

  1. Identification of characteristic mass spectrometric markers for primary biological aerosol particles and comparison with field data from submicron pristine aerosol particles

    NASA Astrophysics Data System (ADS)

    Freutel, F.; Schneider, J.; Zorn, S. R.; Drewnick, F.; Borrmann, S.; Hoffmann, T.; Martin, S. T.

    2009-04-01

    The contribution of primary biological aerosol (PBA) to the total aerosol particle concentration is estimated to range between 25 and 80%, depending on location and season. Especially in the tropical rain forest it is expected that PBA is a major source of particles in the supermicron range, and is also an important fraction of the submicron aerosol. PBA particles like plant fragments, pollen, spores, fungi, viruses etc. contain chemical compounds as proteins, sugars, amino acids, chlorophyll, and cellular material as cellulose. For this reason we have performed mass spectrometric laboratory measurements (Aerodyne C-ToF and W-ToF AMS, single particle laser ablation instrument SPLAT) on pure submicron aerosol particles containing typical PBA compounds in order to identify typical mass spectral patterns of these compounds and to explain the observed fragmentation patterns on the basis of molecular structures. These laboratory data were compared to submicron particle mass spectra obtained during AMAZE-08 (Amazonian Aerosol CharacteriZation Experiment, Brazil, February/March 2008). The results indicate that characteristic m/z ratios for carbohydrates (e.g., glucose, saccharose, levoglucosan, mannitol) can be identified, for example m/z = 60(C2H4O2+) or m/z = 61(C2H5O2+). Certain characteristic peaks for amino acids were also identified in the laboratory experiments. In the field data from AMAZE-08, these characteristic peaks for carbohydrates and amino acids were found, and their contribution to the total organic mass was estimated to about 5%. Fragment ions from peptides and small proteins were also identified in laboratory experiments. Larger proteins, however, seem to become oxidized to CO2+ to a large extend in the vaporizing process of the AMS. Thus, detection of proteins in atmospheric aerosol particles with the AMS appears to be difficult.

  2. Aerosol formation from high-velocity uranium drops: Comparison of number and mass distributions. Final report

    SciTech Connect

    Rader, D.J.; Benson, D.A.

    1995-05-01

    This report presents the results of an experimental study of the aerosol produced by the combustion of high-velocity molten-uranium droplets produced by the simultaneous heating and electromagnetic launch of uranium wires. These tests are intended to simulate the reduction of high-velocity fragments into aerosol in high-explosive detonations or reactor accidents involving nuclear materials. As reported earlier, the resulting aerosol consists mainly of web-like chain agglomerates. A condensation nucleus counter was used to investigate the decay of the total particle concentration due to coagulation and losses. Number size distributions based on mobility equivalent diameter obtained soon after launch with a Differential Mobility Particle Sizer showed lognormal distributions with an initial count median diameter (CMD) of 0.3 {mu}m and a geometric standard deviation, {sigma}{sub g} of about 2; the CMD was found to increase and {sigma}{sub g} decrease with time due to coagulation. Mass size distributions based on aerodynamic diameter were obtained for the first time with a Microorifice Uniform Deposit Impactor, which showed lognormal distributions with mass median aerodynamic diameters of about 0.5 {mu}m and an aerodynamic geometric standard deviation of about 2. Approximate methods for converting between number and mass distributions and between mobility and aerodynamic equivalent diameters are presented.

  3. Urban organic aerosols measured by single particle mass spectrometry in the megacity of London

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Harrison, R. M.

    2011-02-01

    During the month of October 2006, as part of the REPARTEE-I experiment (Regent's Park and Tower Environmental Experiment) an Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed at an urban background location in the city of London, UK. Fifteen particle types were classified, some of which were accompanied by Aerosol Mass Spectrometer (AMS) quantitative aerosol mass loading measurements (Dall'Osto et al., 2009a, b). In this manuscript the origins and properties of four particle types associated with locally generated aerosols, independent of the air mass type advected into London, are examined. One particle type, originating from lubricating oil (referred to as Ca-EC), was associated with morning rush hour traffic emissions. A second particle type, composed of both inorganic and organic species (called Na-EC-OC), was found enhanced in particle number concentration during evening time periods, and is likely to originate from a source operating at this time of day, or more probably from condensation of semi-volatile species, and contains both primary and secondary components. A third class, internally mixed with organic carbon and sulphate (called OC), was found to spike both in the morning and evenings. The fourth class (SOA-PAH) exhibited maximum frequency during the warmest part of the day, and a number of factors point towards secondary production from traffic-related volatile aromatic compounds. Single particle mass spectra of this particle type showed an oxidized polycyclic aromatic compound signature. Finally, a comparison of ATOFMS particle class data is made with factors obtained by Positive Matrix Factorization from AMS data.. Both the Ca-EC and OC particle types correlate with the AMS HOA primary organic fraction (R2 = 0.65 and 0.50 respectively), and Na-EC-OC, but not SOA-PAH, which correlates weakly with the AMS OOA secondary organic aerosol factor (R2 = 0.35). A detailed analysis was conducted to identify ATOFMS particle type(s) representative

  4. Bio-Aerosol Detection Using Mass Spectrometry: Public Health Applications

    SciTech Connect

    Ludvigson, Laura D.

    2004-01-01

    I recently spent a summer as an intern at the Lawrence Livermore National Laboratory. I worked on a project involving the real-time, reagentless, single cell detection of aerosolized pathogens using a novel mass spectrometry approach called Bio-Aerosol Mass Spectrometry (BAMS). Based upon preliminary results showing the differentiation capabilities of BAMS, I would like to explore the development and use of this novel detection system in the context of both environmental and clinical sample pathogen detection. I would also like to explore the broader public health applications that a system such as BAMS might have in terms of infectious disease prevention and control. In order to appreciate the potential of this instrument, I will demonstrate the need for better pathogen detection methods, and outline the instrumentation, data analysis and preliminary results that lead me toward a desire to explore this technology further. I will also discuss potential experiments for the future along with possible problems that may be encountered along the way.

  5. Organosulfates and organic acids in Arctic aerosols: speciation, annual variation and concentration levels

    NASA Astrophysics Data System (ADS)

    Hansen, A. M. K.; Kristensen, K.; Nguyen, Q. T.; Zare, A.; Cozzi, F.; Nøjgaard, J. K.; Skov, H.; Brandt, J.; Christensen, J. H.; Ström, J.; Tunved, P.; Krejci, R.; Glasius, M.

    2014-02-01

    Sources, composition and occurrence of secondary organic aerosols (SOA) in the Arctic were investigated at Zeppelin Mountain, Svalbard, and Station Nord, northeast Greenland, during the full annual cycle of 2008 and 2010 respectively. We focused on the speciation of three types of SOA tracers: organic acids, organosulfates and nitrooxy organosulfates from both anthropogenic and biogenic precursors, here presenting organosulfate concentrations and compositions during a full annual cycle and chemical speciation of organosulfates in Arctic aerosols for the first time. Aerosol samples were analysed using High Performance Liquid Chromatography coupled to a quadrupole Time-of-Flight mass spectrometer (HPLC-q-TOF-MS). A total of 11 organic acids (terpenylic acid, benzoic acid, phthalic acid, pinic acid, suberic acid, azelaic acid, adipic acid, pimelic acid, pinonic acid, diaterpenylic acid acetate (DTAA) and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA)), 12 organosulfates and one nitrooxy organosulfate were identified at the two sites. Six out of the 12 organosulfates are reported for the first time. Concentrations of organosulfates follow a distinct annual pattern at Station Nord, where high concentration were observed in late winter and early spring, with a mean total concentration of 47 (±14) ng m-3, accounting for 7 (±2)% of total organic matter, contrary to a considerably lower organosulfate mean concentration of 2 (±3) ng m-3 (accounting for 1 (±1)% of total organic matter) observed during the rest of the year. The organic acids followed the same temporal trend as the organosulfates at Station Nord; however the variations in organic acid concentrations were less pronounced, with a total mean organic acid concentration of 11.5 (±4) ng m-3 (accounting for 1.7 (±0.6)% of total organic matter) in late winter and early spring, and 2.2 (±1) ng m-3 (accounting for 0.9 (±0.4)% of total organic matter) during the rest of the year. At Zeppelin Mountain

  6. Seasonal differences in aerosol water may reconcile AOT and surface mass measurements in the Southeast U.S.

    NASA Astrophysics Data System (ADS)

    Nguyen, T. K. V.; Ghate, V. P.; Carlton, A. M. G.

    2015-12-01

    Summertime aerosol optical thickness (AOT) in the Southeast U.S. is high and sharply enhanced (2-3 times) compared to wintertime AOT. This seasonal pattern is unique to the Southeast U.S. and is of particular interest because temperatures there have not warmed over the past 100 years, contrasting with trends in other U.S. regions. Some investigators hypothesize the Southeast temperature trend is due to secondary organic aerosols (SOA) formed from interactions of biogenic volatile organic compounds (BVOCs) and anthropogenic emissions that create a cooling haze. However, aerosol measurements made at the surface do not exhibit strong seasonal differences in mass or organic fraction to support this hypothesis. In this work, we attempt to reconcile the spatial and temporal distribution of AOT over the U.S. with surface mass measurements by examining trends in particle-phase liquid water, an aerosol constituent that effectively scatters radiation and is removed from aerosols in mass measurements at routine surface monitoring sites. We employ the thermodynamic model ISORROPIA (v2.1) to estimate surface and aloft aerosol water mass concentrations at locations of Interagency Monitoring of Protected Visual Environments (IMPROVE) sites using measured speciated ion mass concentrations and NCEP North American Regional Reanalysis (NARR) meteorological data. Results demonstrate strong seasonal differences in aerosol water in the eastern compared to the western part of the U.S., consistent with geographic patterns in AOT. The highest mean regional seasonal difference from 2000 to 2007 is 5.5 μg m-3 and occurs the Southeast, while the lowest is 0.44 μg m-3 and occurs in the dry Mountain West. Our findings suggest 1) similarity between spatial trends in aerosol water in the U.S. and previously published AOT data from the MODIS-TERRA instrument and 2) similar interannual trends in mean aerosol water and previously published interannual AOT trends from MISR, MODIS-TERRA, MODIS

  7. Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry.

    PubMed

    Farmer, D K; Matsunaga, A; Docherty, K S; Surratt, J D; Seinfeld, J H; Ziemann, P J; Jimenez, J L

    2010-04-13

    Organonitrates (ON) are important products of gas-phase oxidation of volatile organic compounds in the troposphere; some models predict, and laboratory studies show, the formation of large, multifunctional ON with vapor pressures low enough to partition to the particle phase. Organosulfates (OS) have also been recently detected in secondary organic aerosol. Despite their potential importance, ON and OS remain a nearly unexplored aspect of atmospheric chemistry because few studies have quantified particulate ON or OS in ambient air. We report the response of a high-resolution time-of-flight aerosol mass spectrometer (AMS) to aerosol ON and OS standards and mixtures. We quantify the potentially substantial underestimation of organic aerosol O/C, commonly used as a metric for aging, and N/C. Most of the ON-nitrogen appears as NO(x)+ ions in the AMS, which are typically dominated by inorganic nitrate. Minor organonitrogen ions are observed although their identity and intensity vary between standards. We evaluate the potential for using NO(x)+ fragment ratios, organonitrogen ions, HNO(3)+ ions, the ammonium balance of the nominally inorganic ions, and comparison to ion-chromatography instruments to constrain the concentrations of ON for ambient datasets, and apply these techniques to a field study in Riverside, CA. OS manifests as separate organic and sulfate components in the AMS with minimal organosulfur fragments and little difference in fragmentation from inorganic sulfate. The low thermal stability of ON and OS likely causes similar detection difficulties for other aerosol mass spectrometers using vaporization and/or ionization techniques with similar or larger energy, which has likely led to an underappreciation of these species.

  8. In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft

    NASA Astrophysics Data System (ADS)

    Wagner, N. L.; Brock, C. A.; Angevine, W. M.; Beyersdorf, A.; Campuzano-Jost, P.; Day, D. A.; de Gouw, J. A.; Diskin, G. S.; Gordon, T. D.; Graus, M. G.; Huey, G.; Jimenez, J. L.; Lack, D. A.; Liao, J.; Liu, X.; Markovic, M. Z.; Middlebrook, A. M.; Mikoviny, T.; Peischl, J.; Perring, A. E.; Richardson, M. S.; Ryerson, T. B.; Schwarz, J. P.; Warneke, C.; Welti, A.; Wisthaler, A.; Ziemba, L. D.; Murphy, D. M.

    2015-02-01

    Vertical profiles of submicron aerosol over the southeastern United States (SEUS) during the summertime from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO). Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10% larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA) were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD), was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10% to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary organic aerosol (SOA) aloft to explain the summertime enhancement of AOD (2-3 times greater than winter) over the southeastern United States. In contrast to this hypothesis, the modest enhancement we observed in the transition layer was not dominated by OA and was not a large fraction of the summertime AOD.

  9. Ultrasensitive detection of inhaled organic aerosol particles by accelerator mass spectrometry.

    PubMed

    Parkhomchuk, E V; Gulevich, D G; Taratayko, A I; Baklanov, A M; Selivanova, A V; Trubitsyna, T A; Voronova, I V; Kalinkin, P N; Okunev, A G; Rastigeev, S A; Reznikov, V A; Semeykina, V S; Sashkina, K A; Parkhomchuk, V V

    2016-09-01

    Accelerator mass spectrometry (AMS) was shown to be applicable for studying the penetration of organic aerosols, inhaled by laboratory mice at ultra-low concentration ca. 10(3) cm(-3). We synthesized polystyrene (PS) beads, composed of radiocarbon-labeled styrene, for testing them as model organic aerosols. As a source of radiocarbon we used methyl alcohol with radioactivity. Radiolabeled polystyrene beads were obtained by emulsifier-free emulsion polymerization of synthesized (14)C-styrene initiated by K2S2O8 in aqueous media. Aerosol particles were produced by pneumatic spraying of diluted (14)C-PS latex. Mice inhaled (14)C-PS aerosol consisting of the mix of 10(3) 225-nm particles per 1 cm(3) and 5·10(3) 25-nm particles per 1 cm(3) for 30 min every day during five days. Several millions of 225-nm particles deposited in the lungs and slowly excreted from them during two weeks of postexposure. Penetration of particles matter was also observed for liver, kidneys and brain, but not for a heart.

  10. Ambient Observations of Organic Nitrogen Compounds in Submicrometer Aerosols in New York Using High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zhou, S.; Ge, X.; Xu, J.; Sun, Y.; Zhang, Q.

    2015-12-01

    Organic nitrogen (ON) compounds, which include amines, nitriles, organic nitrates, amides, and N-containing aromatic heterocycles, are an important class of compounds ubiquitously detected in atmospheric particles and fog and cloud droplets. Previous studies indicate that these compounds can make up a significant fraction (20-80%) of the total nitrogen (N) content in atmospheric condensed phases and play important roles in new particle formation and growth and affecting the optical and hygroscopicity of aerosols. In this study, we report the observation of ON compounds in submicrometer particles (PM1) at two locations in New York based on measurements using Aerodyne high-resolution time-of-flight mass spectrometer (HR-ToF-AMS). One study was conducted as part of the US Department of Energy funded Aerosol Lifecyle - Intensive Operation Period (ALC-IOP) campaign at Brookhaven National Lab (BNL, 40.871˚N, 72.89˚W) in summer, 2011 and the other was conducted at the Queen's College (QC) in New York City (NYC) in summer, 2009. We observed a notable amount of N-containing organic fragment ions, CxHyNp+ and CxHyOzNp+, in the AMS spectra of organic aerosols at both locations and found that they were mainly associated with amino functional groups. Compared with results from lab experiments, the C3H8N+ at m/z = 58 was primarily attributed to trimethylamine. In addition, a significant amount of organonitrates was observed at BNL. Positive matrix factorization (PMF) analysis of the high resolution mass spectra (HRMS) of organic aerosols identified a unique nitrogen-enriched OA (NOA) factor with elevated nitrogen-to-carbon (N/C) at both BNL and QC. Analysis of the size distributions, volatility profiles, and correlations with external tracer indicates that acid-base reactions of amino compounds with sulfate and acidic gas were mainly responsible for the formation of amine salts. Photochemical production was also observed to play a role in the formation of NOA. Bivariate polar

  11. Concentration Effects on the Thermophoresis of Aerosol Spheres.

    PubMed

    Keh; Ho

    1999-08-01

    The thermophoretic motion of a homogeneous suspension of identical spherical particles of arbitrary thermal conductivity and surface properties is considered under conditions of small Knudsen, Peclet, and Reynolds numbers. The effects of interaction of the individual particles are taken into explicit account by employing a unit cell model which is known to provide good predictions for the sedimentation of monodisperse suspensions of spherical particles. The appropriate equations of conservation of energy and momentum are solved for each cell, in which a spherical particle is envisaged to be surrounded by a concentric shell of suspending fluid, and the thermophoretic migration velocity of the particle is calculated for various cases. Analytical expressions of this mean particle velocity are obtained in closed form as functions of the volume fraction of the particles. Comparisons between the ensemble-averaged thermophoretic velocity of a test particle in a dilute suspension and our cell-model results are made. A parallel analysis for the sedimentation of aerosol spheres is also presented. Copyright 1999 Academic Press.

  12. Concentration Effects and Ion Properties Controlling the Fractionation of Halides during Aerosol Formation

    NASA Technical Reports Server (NTRS)

    Guzman, Marcelo I.; Athalye, Richa R.; Rodriguez, Jose M.

    2012-01-01

    During the aerosolization process at the sea surface, halides are incorporated into aerosol droplets, where they may play an important role in tropospheric ozone chemistry. Although this process may significantly contribute to the formation of reactive gas phase molecular halogens, little is known about the environmental factors that control how halides selectively accumulate at the air-water interface. In this study, the production of sea spray aerosol is simulated using electrospray ionization (ESI) of 100 nM equimolar solutions of NaCl, NaBr, NaI, NaNO2, NaNO3, NaClO4, and NaIO4. The microdroplets generated are analyzed by mass spectrometry to study the comparative enrichment of anions (f (Isub x-)) and their correlation with ion properties. Although no correlation exists between f (sub x-) and the limiting equivalent ionic conductivity, the correlation coefficient of the linear fit with the size of the anions R(sub x-), dehydration free-energy ?Gdehyd, and polarizability alpha, follows the order: (R(sub x-)(exp -2)) > (R(sub x-)(exp -1)) >(R(sub x-) > delta G(sub dehyd) > alpha. The same pure physical process is observed in H2O and D2O. The factor f (sub x-) does not change with pH (6.8-8.6), counterion (Li+, Na+, K+, and Cs+) substitution effects, or solvent polarity changes in methanol - and ethanol-water mixtures (0 <= xH2O <= 1). Sodium polysorbate 20 surfactant is used to modify the structure of the interface. Despite the observed enrichment of I- on the air-water interface of equimolar solutions, our results of seawater mimic samples agree with a model in which the interfacial composition is increasingly enriched in I- < Br- < Cl- over the oceanic boundary layer due to concentration effects in sea spray aerosol formation.

  13. Air mass origin and its influence on radionuclide activities ( 7Be and 210Pb) in aerosol particles at a coastal site in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Dueñas, C.; Orza, J. A. G.; Cabello, M.; Fernández, M. C.; Cañete, S.; Pérez, M.; Gordo, E.

    2011-07-01

    Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of 7Be and 210Pb in aerosols at Málaga (36° 43' 40″ N; 4° 28' 8″ W) for the period 2000-2006 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory clusters. The average concentration values of 7Be and 210Pb over the 7 year period have been found to be 4.6 and 0.58 mBq m -3, respectively, with mean aerosol mass concentration of 53.6 μg m -3. The identified air flow types arriving at Málaga reflect the transitional location of the Iberian Peninsula and show significant differences in radionuclide activities. Air concentrations of both nuclides and the aerosol mass concentration are controlled predominantly by the synoptic scenarios leading to the entrance of dust-laden continental flows from northern Africa and the arrival of polar maritime air masses, as implied by the strong correlations found between the monthly frequencies of the different air masses and the specific activities of both radionuclides. Correlations between activity concentrations and precipitation are significant though lower than with air masses.

  14. Constraining aerosol optical models using ground-based, collocated particle size and mass measurements in variable air mass regimes during the 7-SEAS/Dongsha experiment

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    During the spring of 2010, NASA Goddard's COMMIT ground-based mobile laboratory was stationed on Dongsha Island off the southwest coast of Taiwan, in preparation for the upcoming 2012 7-SEAS field campaign. The measurement period offered a unique opportunity for conducting detailed investigations of the optical properties of aerosols associated with different air mass regimes including background maritime and those contaminated by anthropogenic air pollution and mineral dust. What appears to be the first time for this region, a shortwave optical closure experiment (λ = 550 nm) for both scattering and absorption was attempted over a 12-day period during which aerosols exhibited the most change. Constraints to the optical model included combined SMPS and APS number concentration data for a continuum of fine and coarse-mode particle sizes up to PM2.5. We also take advantage of an IMPROVE chemical sampler to help constrain aerosol composition and mass partitioning of key elemental species including sea-salt, particulate organic matter, soil, non sea-salt sulfate, nitrate, and elemental carbon. Achieving full optical closure is hampered by limitations in accounting for the role of water vapor in the system, uncertainties in the instruments and the need for further knowledge in the source apportionment of the model's major chemical components. Nonetheless, our results demonstrate that the observed aerosol scattering and absorption for these diverse air masses are reasonably captured by the model, where peak aerosol events and transitions between key aerosols types are evident. Signatures of heavy polluted aerosol composed mostly of ammonium and non sea-salt sulfate mixed with some dust with transitions to background sea-salt conditions are apparent in the absorption data, which is particularly reassuring owing to the large variability in the imaginary component of the refractive indices. Consistency between the measured and modeled optical parameters serves as an

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  16. Mass-based hygroscopicity parameter interaction model and measurement of atmospheric aerosol water uptake

    NASA Astrophysics Data System (ADS)

    Mikhailov, E.; Merkulov, V.; Vlasenko, S.; Rose, D.; Pöschl, U.

    2011-11-01

    In this study we derive and apply a mass-based hygroscopicity parameter interaction model for efficient description of concentration-dependent water uptake by atmospheric aerosol particles. The model approach builds on the single hygroscopicity parameter model of Petters and Kreidenweis (2007). We introduce an observable mass-based hygroscopicity parameter κm, which can be deconvoluted into a dilute intrinsic hygroscopicity parameter (κm,∞) and additional self- and cross-interaction parameters describing non-ideal solution behavior and concentration dependencies of single- and multi-component systems. For sodium chloride, the κm-interaction model (KIM) captures the observed concentration and humidity dependence of the hygroscopicity parameter and is in good agreement with an accurate reference model based on the Pitzer ion-interaction approach (Aerosol Inorganic Model, AIM). For atmospheric aerosol samples collected from boreal rural air and from pristine tropical rainforest air (secondary organic aerosol) we present first mass-based measurements of water uptake over a wide range of relative humidity (1-99%) obtained with a new filter-based differential hygroscopicity analyzer (FDHA) technique. By application of KIM to the measurement data we can distinguish three different regimes of hygroscopicity in the investigated aerosol samples: (I) A quasi-eutonic regime at low relative humidity (~60% RH) where the solutes co-exist in an aqueous and non-aqueous phase; (II) a gradually deliquescent regime at intermediate humidity (~60%-90% RH) where different solutes undergo gradual dissolution in the aqueous phase; and (III) a dilute regime at high humidity (≳90% RH) where the solutes are fully dissolved approaching their dilute intrinsic hygroscopicity. The characteristic features of the three hygroscopicity regimes are similar for both samples, while the RH threshold values vary as expected for samples of different chemical composition. In each regime, the

  17. Spinning-disk generation and drying of monodisperse solid aerosols with output concentrations sufficient for single-breath inhalation studies.

    PubMed

    Byron, P R; Hickey, A J

    1987-01-01

    The air-driven spinning-disk aerosol generator was modified to allow the production of monodisperse dry spherical aerosols of disodium fluorescein (as model solute) in high output concentrations. Output concentrations were determined by filtration. Optical and aerodynamic size distributions were determined microscopically (after electrostatic precipitation) and by cascade impaction. The generator housing allowed the entrainment of 25-microns primary aqueous solution droplets in a 10-L X min-1 downward flow of dry, filtered air. Internal equipment surfaces were machined flush and polished to minimize aerosol losses. Primary droplets were dried within a stainless steel pipe encased in a tube furnace. Water vapor was removed by diffusion drying. Disk-driven air, satellite droplets, and additional dilution air were vented to waste without using a vacuum. Generator yields were increased by reducing the size of the satellite droplet extraction gap. Aerosols were generated reproducibly by delivering aqueous solutions at a rate of 0.2 mL X min-1 to the center of the disk and spinning at 1000 rps. Dry aerosols, with mass median aerodynamic diameters of 2, 4.9, and 9 microns, were produced in concentrations of 0.89, 5.48, and 54.6 micrograms X L-1 from aqueous solutions containing 0.0374, 0.584, and 3.4% solute by weight. Geometric standard deviations were less than 1.2 in all cases. Concentrations are several times higher than others in the literature and are suitable for single-breath inhalation studies of therapeutic aerosol deposition and effect.

  18. 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.

  19. Molecular composition of organic aerosols in central Amazonia: an ultra-high-resolution mass spectrometry study

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan; Godoi, Ricardo H. M.; Connors, Sarah; Levine, James G.; Archibald, Alex T.; Godoi, Ana F. L.; Paralovo, Sarah L.; Barbosa, Cybelli G. G.; Souza, Rodrigo A. F.; Manzi, Antonio O.; Seco, Roger; Sjostedt, Steve; Park, Jeong-Hoo; Guenther, Alex; Kim, Saewung; Smith, James; Martin, Scot T.; Kalberer, Markus

    2016-09-01

    The Amazon Basin plays key role in atmospheric chemistry, biodiversity and climate change. In this study we applied nanoelectrospray (nanoESI) ultra-high-resolution mass spectrometry (UHRMS) for the analysis of the organic fraction of PM2.5 aerosol samples collected during dry and wet seasons at a site in central Amazonia receiving background air masses, biomass burning and urban pollution. Comprehensive mass spectral data evaluation methods (e.g. Kendrick mass defect, Van Krevelen diagrams, carbon oxidation state and aromaticity equivalent) were used to identify compound classes and mass distributions of the detected species. Nitrogen- and/or sulfur-containing organic species contributed up to 60 % of the total identified number of formulae. A large number of molecular formulae in organic aerosol (OA) were attributed to later-generation nitrogen- and sulfur-containing oxidation products, suggesting that OA composition is affected by biomass burning and other, potentially anthropogenic, sources. Isoprene-derived organosulfate (IEPOX-OS) was found to be the most dominant ion in most of the analysed samples and strongly followed the concentration trends of the gas-phase anthropogenic tracers confirming its mixed anthropogenic-biogenic origin. The presence of oxidised aromatic and nitro-aromatic compounds in the samples suggested a strong influence from biomass burning especially during the dry period. Aerosol samples from the dry period and under enhanced biomass burning conditions contained a large number of molecules with high carbon oxidation state and an increased number of aromatic compounds compared to that from the wet period. The results of this work demonstrate that the studied site is influenced not only by biogenic emissions from the forest but also by biomass burning and potentially other anthropogenic emissions from the neighbouring urban environments.

  20. On the implications of aerosol liquid water and phase separation for organic aerosol mass

    EPA Science Inventory

    Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to org...

  1. Concentrations and sources of organic carbon aerosols in the free troposphere over North America

    NASA Astrophysics Data System (ADS)

    Heald, Colette L.; Jacob, Daniel J.; Turquety, SolèNe; Hudman, Rynda C.; Weber, Rodney J.; Sullivan, Amy P.; Peltier, Richard E.; Atlas, Eliot L.; de Gouw, Joost A.; Warneke, Carsten; Holloway, John S.; Neuman, J. Andrew; Flocke, Frank M.; Seinfeld, John H.

    2006-12-01

    Aircraft measurements of water-soluble organic carbon (WSOC) aerosol over NE North America during summer 2004 (ITCT-2K4) are simulated with a global chemical transport model (GEOS-Chem) to test our understanding of the sources of organic carbon (OC) aerosol in the free troposphere (FT). Elevated concentrations were observed in plumes from boreal fires in Alaska and Canada. WSOC aerosol concentrations outside of these plumes average 0.9 ± 0.9 μg C m-3 in the FT (2-6 km). The corresponding model value is 0.7 ± 0.6 μg C m-3, including 42% from biomass burning, 36% from biogenic secondary organic aerosol (SOA), and 22% from anthropogenic emissions. Previous OC aerosol observations over the NW Pacific in spring 2001 (ACE-Asia) averaged 3.3 ± 2.8 μg C m-3 in the FT, compared to a model value of 0.3 ± 0.3 μg C m-3. WSOC aerosol concentrations in the boundary layer (BL) during ITCT-2K4 are consistent with OC aerosol observed at the IMPROVE surface network. The model is low in the boundary layer by 30%, which we attribute to secondary formation at a rate comparable to primary anthropogenic emission. Observed WSOC aerosol concentrations decrease by a factor of 2 from the BL to the FT, as compared to a factor of 10 decrease for sulfate, indicating that most of the WSOC aerosol in the FT originates in situ. Despite reproducing mean observed WSOC concentrations in the FT to within 25%, the model cannot account for the variance in the observations (R = 0.21). Covariance analysis of FT WSOC aerosol with other measured chemical variables suggests an aqueous-phase mechanism for SOA generation involving biogenic precursors.

  2. Profiling the PM2.5 mass concentration vertical distribution in the boundary layer

    NASA Astrophysics Data System (ADS)

    Tao, Z.; Wang, Z.; Yang, S.; Shan, H.; Ma, X.; Zhang, H.; Zhao, S.; Liu, D.; Xie, C.; Wang, Y.

    2015-12-01

    Fine particle (PM2.5) affects human life and activities directly; the detection of PM2.5 mass concentration profile is very essential due to its practical and scientific meanings (such as, quantifying of air quality and its variability, and improving air quality forecast and assessment). But so far, it is difficult to detect PM2.5 mass concentration profile. The proposed methodology to study the relationship between aerosol extinction coefficient and PM2.5 mass concentration is described, which indicates that the PM2.5 mass concentration profile could be retrieved by combining a charge-coupled device (CCD) side-scatter lidar and a PM2.5 sampling detector. When the relative humidity is less than 70 %, PM2.5 mass concentration is proportional to aerosol extinction coefficient, and then the specific coefficient can be calculated. Using this specific coefficient, aerosol extinction profile is converted to PM2.5 mass concentration profile. Three cases of clean night (on 21 September 2014), pollutant night (on 17 March 2014), and heavy pollutant night (on 13 February 2015) are studied. The characteristic of PM2.5 mass concentration profile in near-ground during these three nights' cases in the western suburb of Hefei city was discussed. The PM2.5 air pollutant concentration is comparatively large in close surface varying with time and altitude. The experiment results show that the CCD side-scatter lidar combined with a PM2.5 detector is an effective and new method to explore pollutant mass concentration profile in near-ground.

  3. Profiling the PM2.5 mass concentration vertical distribution in the boundary layer

    NASA Astrophysics Data System (ADS)

    Tao, Zongming; Wang, Zhenzhu; Yang, Shijun; Shan, Huihui; Ma, Xiaomin; Zhang, Hui; Zhao, Sugui; Liu, Dong; Xie, Chenbo; Wang, Yingjian

    2016-04-01

    Fine particles (PM2.5) affect human life and activities directly; the detection of PM2.5 mass concentration profile is very essential due to its practical and scientific significance (such as the quantification of air quality and its variability as well as the assessment of improving air quality forecast). But so far, it has been difficult to detect PM2.5 mass concentration profile. The proposed methodology to study the relationship between aerosol extinction coefficient and PM2.5 mass concentration is described, which indicates that the PM2.5 mass concentration profile could be retrieved by combining a charge-coupled device (CCD) side-scatter lidar with a PM2.5 sampling detector. When the relative humidity is less than 70 %, PM2.5, mass concentration is proportional to the aerosol extinction coefficient, and then the specific coefficient can be calculated. Through this specific coefficient, aerosol extinction profile is converted to PM2.5 mass concentration profile. Three cases of clean night (on 21 September 2014), pollutant night (on 17 March 2014), and heavy pollutant night (on 13 February 2015) are studied. The characteristics of PM2.5 mass concentration profile at the near-ground level during the cases of these 3 nights in the western suburb of Hefei city were discussed. The PM2.5 air pollutant concentration is comparatively large close to the surface and varies with time and altitude. The experiment results show that the CCD side-scatter lidar combined with a PM2.5 detector is an effective and new method to explore pollutant mass concentration profile at the near-ground level.

  4. MISR Aerosol Air Mass Type Mapping over Mega-City: Validation and Applications

    NASA Astrophysics Data System (ADS)

    Patadia, F.; Kahn, R. A.

    2010-12-01

    Most aerosol air-quality monitoring in mega-city environments is done from scattered ground stations having detailed chemical and optical sampling capabilities. Satellite instruments such as the Multi-angle Imaging SpectroRadiometer (MISR) can retrieve total-column Aerosol Optical Depth (AOD), along with some information about particle microphysical properties. Although the particle property information from MISR is much less detailed than that obtained from the ground sampling stations, the coverage is extensive, making it possible to put individual surface observations into the context of regional aerosol air mass types. This paper presents an analysis of MISR aerosol observations made coincident with aircraft and ground-based instruments during the INTEX-B field campaign. These detailed comparisons of satellite aerosol property retrievals against dedicated field measurements provide the opportunity to validate the retrievals quantitatively at a regional level, and help to improve aerosol representation in retrieval algorithms. Validation of MISR retrieved AOD and other aerosol properties over the INTEX-B study region in and around Mexico City will be presented. MISR’s ability to distinguish among aerosol air mass types will be discussed. The goal of this effort is to use the MISR aerosol property retrievals for mapping both aerosol air mass type and AOD gradients in mega-city environments over the decade-plus that MISR has made global observations.

  5. A balloon-borne aerosol spectrometer for high altitude low aerosol concentration measurements

    SciTech Connect

    Brown, G.S. ); Weiss, R.E. )

    1990-08-01

    Funded by Air Force Wright Aeronautical Laboratory, a new balloon-borne high altitude aerosol spectrometer, for the measurement of cirrus cloud ice crystals, has been developed and successfully flown by Sandia National Laboratories and Radiance Research. This report (1) details the aerosol spectrometer design and construction, (2) discusses data transmission and decoding, (3) presents data collected on three Florida flights in tables and plots. 2 refs., 11 figs., 3 tabs.

  6. Observations of accumulation mode aerosol composition and soot carbon concentrations by means of a high-temperature volatility technique

    NASA Astrophysics Data System (ADS)

    Smith, Michael H.; O'Dowd, Colin D.

    1996-08-01

    A high-temperature volatility system has been deployed for the measurement of the composition and concentration of the accumulation mode aerosol (0.05 μm < r < 1 μm) within the atmospheric boundary layer. This instrumentation comprises a volatility system based around a Particle Measuring Systems ASASP-X optical particle counter, which was operated together with an aethalometer for the direct observation of soot carbon concentrations. By cycling the heater tube through a range of temperatures from near ambient to over 1000°C, size-differentiated information upon aerosol composition may be obtained. Furthermore, by careful selection of analysis temperatures, discrimination is possible between elemental carbon and the more volatile fractions of the soot carbon aerosol. Observations made over the North Sea near the Dutch coast and in the central United Kingdom are presented for differing environmental conditions with soot carbon concentrations ranging from about 100 to over 6000 ng m-3. For polluted conditions over the North Sea the volatility technique clearly showed the dominance of soot carbon particles over other aerosol components with a narrow carbon particle distribution of mode radius around 0.06 μm accounting for about 80% of all particles with radii below 0.1 μm. Under polluted conditions, only about 25% of the total soot carbon aerosol comprised elemental carbon (with the remainder consisting of more volatile material), whereas this proportion rose to around 50% in the lower carbon loadings found in a cleaner maritime air mass. The use of soot carbon loadings as a tracer of anthropogenic aerosol inputs to oceanic regions is explored on the basis of measurements from a NE Atlantic cruise.

  7. Pattern of aerosol mass loading and chemical composition over the atmospheric environment of an urban coastal station

    NASA Astrophysics Data System (ADS)

    Bindu, G.; Nair, Prabha R.; Aryasree, S.; Hegde, Prashant; Jacob, Salu

    2016-02-01

    Aerosol sampling was carried out at four locations in and around Cochin (9°58‧ N, 76°17‧ E), an urban area, located on the southwest coast of India. The gravimetric estimates of aerosol mass loading showed wide range from 78 μg m-3 to >450 μg m-3, occasionally reaching values >500 μg m-3, associated with regional source characteristics. Most of the values were above the air quality standard. Both boundary layer and synoptic scale airflow pattern play role in the temporal features in aerosol mass loading and chemical composition. Chemical analysis of the aerosol samples were done for anionic species viz; F-, Cl-, Br-, NO2-,   NO3-,   PO43-,   SO42- and metallic/cationic species viz; Na, Ca, K, Mg, NH4+, Fe, Al, Cu, Mg, Pb, etc using Ion Chromatography, Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma- Atomic Emission Spectroscopy (ICP-AES). At all the locations, extremely high mass concentration of SO42- was observed with the mean value of 13±6.4 μg m-3 indicating the strong anthropogenic influence. Statistical analysis of the chemical composition data was carried out and the principal factors presented. Seasonal variation of these chemical species along with their percentage contributions and regional variations were also examined. Increase in level of Na in aerosol samples indicated the influence of monsoonal activity. Most of the species showed mass concentrations well above those measured over another coastal site Thiruvananthapuram (8°29‧ N, 76°57‧ E) situated ~220 km south of Cochin revealing the highly localized aerosol features.

  8. 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.

  9. Sources and atmospheric processing of winter aerosols in Seoul, Korea: insights from real-time measurements using a high-resolution aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Kim, Hwajin; Zhang, Qi; Bae, Gwi-Nam; Kim, Jin Young; Bok Lee, Seung

    2017-02-01

    Highly time-resolved chemical characterization of nonrefractory submicrometer particulate matter (NR-PM1) was conducted in Seoul, the capital and largest metropolis of Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The measurements were performed during winter, when elevated particulate matter (PM) pollution events are often observed. This is the first time that detailed real-time aerosol measurement results have been reported from Seoul, Korea, and they reveal valuable insights into the sources and atmospheric processes that contribute to PM pollution in this region. The average concentration of submicron aerosol (PM1 = NR-PM1+ black carbon (BC)) was 27.5 µg m-3, and the total mass was dominated by organics (44 %), followed by nitrate (24 %) and sulfate (10 %). The average atomic ratios of oxygen to carbon (O / C), hydrogen to carbon (H / C), and nitrogen to carbon (N / C) of organic aerosols (OA) were 0.37, 1.79, and 0.018, respectively, which result in an average organic mass-to-carbon (OM / OC) ratio of 1.67. The concentrations (2.6-90.7 µg m-3) and composition of PM1 varied dynamically during the measurement period due to the influences of different meteorological conditions, emission sources, and air mass origins. Five distinct sources of OA were identified via positive matrix factorization (PMF) analysis of the HR-ToF-AMS data: vehicle emissions represented by a hydrocarbon-like OA factor (HOA, O / C = 0.06), cooking activities represented by a cooking OA factor (COA, O / C = 0.14), wood combustion represented by a biomass burning OA factor (BBOA, O / C = 0.34), and secondary organic aerosol (SOA) represented by a semivolatile oxygenated OA factor (SV-OOA, O / C = 0.56) and a low-volatility oxygenated OA factor (LV-OOA, O / C = 0.68). On average, primary OA (POA = HOA + COA + BBOA) accounted for 59 % the OA mass, whereas SV-OOA and LV-OOA contributed 15 and 26 %, respectively. Our results indicate that air

  10. Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Junfeng; Ge, Xinlei; Chen, Yanfang; Shen, Yafei; Zhang, Qi; Sun, Yele; Xu, Jianzhong; Ge, Shun; Yu, Huan; Chen, Mindong

    2016-07-01

    In this work, the Aerodyne soot particle - aerosol mass spectrometer (SP-AMS) was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD) of China, for online characterization of the submicron aerosols (PM1). The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC) simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics). The average PM1 concentration was found to be 28.2 µg m-3, with organics (45 %) as the most abundant component, following by sulfate (19.3 %), nitrate (13.6 %), ammonium (11.1 %), rBC (9.7 %), and chloride (1.3 %). These PM1 species together can reconstruct ˜ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (< 100 nm vacuum aerodynamic diameter) were dominated by organics and rBC, while large particles had significant contributions from secondary inorganic species. Source apportionment of organic aerosols (OA) yielded four OA subcomponents, including hydrocarbon-like OA (HOA), cooking-related OA (COA), semi-volatile oxygenated OA (SV-OOA), and low-volatility oxygenated OA (LV-OOA). Overall, secondary organic aerosol (SOA, equal to the sum of SV-OOA and LV-OOA) dominated the total OA mass (55.5 %), but primary organic aerosol (POA, equal to the sum of HOA and COA) can outweigh SOA in the early morning and evening due to enhanced human activities. High OA concentrations were often associated with high mass fractions of POA and rBC, indicating the important role of anthropogenic emissions during heavy pollution events. The diurnal cycles of nitrate, chloride, and SV-OOA both showed good anti-correlations with air temperatures, suggesting their variations were likely driven by thermodynamic equilibria and gas-to-particle partitioning. On the other hand, in contrast to other species

  11. Factors affecting the indoor concentrations of carbonaceous aerosols of outdoor origin

    SciTech Connect

    Lunden, Melissa M.; Kirchstetter, Thomas W.; Thatcher, Tracy L.; Hering, Susanne V.; Brown, Nancy J.

    2007-06-25

    A field study was conducted in an unoccupied single story residence in Clovis, California to provide data to address issues important to assess the indoor exposure to particles of outdoor origin. Measurements of black and organic carbonaceous aerosols were performed using a variety of methods, resulting in both near real-time measurements as well as integrated filter based measurements. Comparisons of the different measurement methods show that it is crucial to account for gas phase adsorption artifacts when measuring organic carbon (OC). Measured concentrations affected by the emissions of organic compounds sorbed to indoor surfaces imply a higher degree of infiltration of outdoor organic carbon aerosols into the indoor environment for our unoccupied house. Analysis of the indoor and outdoor data for black carbon (BC) aerosols show that, on average, the indoor concentration of black carbon aerosols behaves in a similar manner to sulfate aerosols. In contrast, organic carbon aerosols are subject to chemical transformations indoors that, for our unoccupied home, resulted in lower indoor OC concentrations than would be expected by physical loss mechanisms alone. These results show that gas to particle partitioning of organic compounds, as well as gas to surface interactions within the residence, are an important process governing the indoor concentration to OC aerosols of outdoor origin.

  12. Middle East measurements of concentration and size distribution of aerosol particles for coastal zones

    NASA Astrophysics Data System (ADS)

    Bendersky, Sergey; Kopeika, Norman S.; Blaunstein, Natan S.

    2005-10-01

    Recently, an extension of the Navy Aerosol Model (NAM) was proposed based on analysis of an extensive series of measurements at the Irish Atlantic Coast and at the French Mediterranean Coast. We confirm the relevance of that work for the distant eastern Meditteranean and extend several coefficients of that coastal model, proposed by Piazzola et al. for the Meditteranean Coast (a form of the Navy Aerosol Model), to midland Middle East coastal environments. This analysis is based on data collected at three different Middle East coastal areas: the Negev Desert (Eilat) Red Sea Coast, the Sea of Galilee (Tiberias) Coast, and the Mediterranean (Haifa) Coast. Aerosol size distributions are compared with those obtained through measurements carried out over the Atlantic, Pacific, and Indian Ocean Coasts, and Mediterranean, and Baltic Seas Coasts. An analysis of these different results allows better understanding of the similarities and differences between different coastal lake, sea, and open ocean zones. It is shown that in the coastal regions in Israel, compared to open ocean and other sea zones, larger differences in aerosol particle concentration are observed. The aerosol particle concentrations and their dependences on wind speed for these coastal zones are analyzed and discussed. We propose to classify the aerosol distribution models to either: 1. a coastal model with marine aerosol domination; 2. a coastal model with continental aerosol domination (referred to as midland coast in this work); or 3. a coastal model with balanced marine and continental conditions.

  13. Modal structure of chemical mass size distribution in the high Arctic aerosol

    NASA Astrophysics Data System (ADS)

    Hillamo, Risto; Kerminen, Veli-Matti; Aurela, Minna; MäKelä, Timo; Maenhaut, Willy; Leek, Caroline

    2001-11-01

    Chemical mass size distributions of aerosol particles were measured in the remote marine boundary layer over the central Arctic Ocean as part of the Atmospheric Research Program on the Arctic Ocean Expedition 1996 (AOE-96). An inertial impaction method was used to classify aerosol particles into different size classes for subsequent chemical analysis. The particle chemical composition was determined by ion chromatography and by the particle-induced X-ray emission technique. Continuous particle size spectra were extracted from the raw data using a data inversion method. Clear and varying modal structures for aerosols consisting of primary sea-salt particles or of secondary particles related to dimethyl sulfide emissions were found. Concentration levels of all modes decreased rapidly when the distance from open sea increased. In the submicrometer size range the major ions found by ion chromatography were sulfate, methane sulfonate, and ammonium. They had most of the time a clear Aitken mode and one or two accumulation modes, with aerodynamic mass median diameters around 0.1 μm, 0.3 μm, and between 0.5-1.0 μm, respectively. The overall submicron size distributions of these three ions were quite similar, suggesting that they were internally mixed over most of this size range. The corresponding modal structure was consistent with the mass size distributions derived from the particle number size distributions measured with a differential mobility particle sizer. The Aitken to accumulation mode mass ratio for nss-sulfate and MSA was substantially higher during clear skies than during cloudy periods. Primary sea-salt particles formed a mode with an aerodynamic mass median diameter around 2 μm. In general, the resulting continuous mass size distributions displayed a clear modal structure consistent with our understanding of the two known major source mechanisms. One is the sea-salt aerosol emerging from seawater by bubble bursting. The other is related to

  14. Winter monsoon variability and its impact on aerosol concentrations in East Asia.

    PubMed

    Jeong, Jaein I; Park, Rokjin J

    2017-02-01

    We investigate the relationship between winter aerosol concentrations over East Asia and variability in the East Asian winter monsoon (EAWM) using GEOS-Chem 3-D global chemical transport model simulations and ground-based aerosol concentration data. We find that both observed and modeled surface aerosol concentrations have strong relationships with the intensity of the EAWM over northern (30-50°N, 100-140°E) and southern (20-30°N, 100-140°E) East Asia. In strong winter monsoon years, compared to weak winter monsoon years, lower and higher surface PM2.5 concentrations by up to 25% are shown over northern and southern East Asia, respectively. Analysis of the simulated results indicates that the southward transport of aerosols is a key process controlling changes in aerosol concentrations over East Asia associated with the EAWM. Variability in the EAWM is found to play a major role in interannual variations in aerosol concentrations; consequently, changes in the EAWM will be important for understanding future changes in wintertime air quality over East Asia.

  15. Characterization of ice-nucleating bacteria using on-line electron impact ionization aerosol mass spectrometry.

    PubMed

    Wolf, R; Slowik, J G; Schaupp, C; Amato, P; Saathoff, H; Möhler, O; Prévôt, A S H; Baltensperger, U

    2015-04-01

    The mass spectral signatures of airborne bacteria were measured and analyzed in cloud simulation experiments at the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) facility. Suspensions of cultured cells in pure water were sprayed into the aerosol and cloud chambers forming an aerosol which consisted of intact cells, cell fragments and residual particles from the agar medium in which the bacteria were cultured. The aerosol particles were analyzed with a high-resolution time-of-flight aerosol mass spectrometer equipped with a newly developed PM2.5 aerodynamic lens. Positive matrix factorization (PMF) using the multilinear engine (ME-2) source apportionment was applied to deconvolve the bacteria and agar mass spectral signatures. The bacteria mass fraction contributed between 75 and 95% depending on the aerosol generation, with the remaining mass attributed to agar. We present mass spectra of Pseudomonas syringae and Pseudomonas fluorescens bacteria typical for ice-nucleation active bacteria in the atmosphere to facilitate the distinction of airborne bacteria from other constituents in ambient aerosol, e.g. by PMF/ME-2 source apportionment analyses. Nitrogen-containing ions were the most salient feature of the bacteria mass spectra, and a combination of C4 H8 N(+) (m/z 70) and C5 H12 N(+) (m/z 86) may be used as marker ions.

  16. Mass spectrometry investigation of Titan aerosols analogs formed with traces of aromatic compounds

    NASA Astrophysics Data System (ADS)

    Gautier, Thomas; Trainer, Melissa; Sebree, Joshua; Li, Xiang; Pinnick, Veronica; Getty, Stephanie; Brinckerhoff, Will

    2016-06-01

    The detection of benzene at ppm levels in Titan's atmosphere [1] by Cassini's Ion and Neutral Mass Spectrometer (INMS) supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titan's aerosols formation. In laboratory studies it has been shown that these aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation [2] and be used to dope the production of aerosol analogs [3]. In this work we investigate the effect on the aerosol composition and growth pattern of the chemical nature of the aromatic reactant used to produce aerosol. Analysis are performed using Laser Desorption-Time of Flight mass spectrometry (LD-TOF) and Fourier Transform Infrared Spectroscopy (FTIR) Infrared analysis of our samples shows that inclusion of aromatic compounds as trace precursors allows to better fit laboratory data to Titan aerosol spectra observed by Cassini [3,4]. The improvement is especially visible on the far infrared (˜200 cm-1) bands observed by CIRS [5]. LDMS results show that the aerosol growth patterns depend both on the number of rings and on the nitrogen content of the trace precursor used. We also perform MS/MS analysis on some prominent peaks of aerosol mass spectra. This MS/MS approach allows us to identify some of the key compounds in the aerosol growth processes.

  17. Impact of maritime air mass trajectories on the Western European coast urban aerosol.

    PubMed

    Almeida, S M; Silva, A I; Freitas, M C; Dzung, H M; Caseiro, A; Pio, C A

    2013-01-01

    Lisbon is the largest urban area in the Western European coast. Due to this geographical position the Atlantic Ocean serves as an important source of particles and plays an important role in many atmospheric processes. The main objectives of this study were to (1) perform a chemical characterization of particulate matter (PM2.5) sampled in Lisbon, (2) identify the main sources of particles, (3) determine PM contribution to this urban area, and (4) assess the impact of maritime air mass trajectories on concentration and composition of respirable PM sampled in Lisbon. During 2007, PM2.5 was collected on a daily basis in the center of Lisbon with a Partisol sampler. The exposed Teflon filters were measured by gravimetry and cut into two parts: one for analysis by instrumental neutron activation analysis (INAA) and the other by ion chromatography (IC). Principal component analysis (PCA) and multilinear regression analysis (MLRA) were used to identify possible sources of PM2.5 and determine mass contribution. Five main groups of sources were identified: secondary aerosols, traffic, calcium, soil, and sea. Four-day backtracking trajectories ending in Lisbon at the starting sampling time were calculated using the HYSPLIT model. Results showed that maritime transport scenarios were frequent. These episodes were characterized by a significant decrease of anthropogenic aerosol concentrations and exerted a significant role on air quality in this urban area.

  18. Uptake of nitric acid, ammonia, and organics in orographic clouds: mass spectrometric analyses of droplet residual and interstitial aerosol particles

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes; Mertes, Stephan; van Pinxteren, Dominik; Herrmann, Hartmut; Borrmann, Stephan

    2017-01-01

    Concurrent in situ analyses of interstitial aerosol and cloud droplet residues have been conducted at the Schmücke mountain site during the Hill Cap Cloud Thuringia campaign in central Germany in September and October 2010. Cloud droplets were sampled from warm clouds (temperatures between -3 and +16 °C) by a counterflow virtual impactor and the submicron-sized residues were analyzed by a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS), while the interstitial aerosol composition was measured by an high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). During cloud-free periods, the submicron out-of-cloud aerosol was analyzed using both instruments, allowing for intercomparison between the two instruments. Further instrumentation included black carbon measurements and optical particle counters for the aerosol particles as well as optical sizing instrumentation for the cloud droplets. The results show that, under cloud conditions, on average 85 % of the submicron aerosol mass partitioned into the cloud liquid phase. Scavenging efficiencies of nitrate, ammonium, sulfate, and organics ranged between 60 and 100 %, with nitrate having, in general, the highest values. For black carbon, the scavenging efficiency was markedly lower (about 24 %). The nitrate and ammonium mass fractions were found to be markedly enhanced in cloud residues, indicating uptake of gaseous nitric acid and ammonia into the aqueous phase. This effect was found to be temperature dependent: at lower temperatures, the nitrate and ammonium mass fractions in the residues were higher. Also, the oxidation state of the organic matter in cloud residues was found to be temperature dependent: the O : C ratio was lower at higher temperatures. A possible explanation for this observation is a more effective uptake and/or higher concentrations of low-oxidized water-soluble volatile organic compounds, possibly of biogenic origin, at higher temperatures. Organic nitrates were observed

  19. Recent Field Measurements of Ice Nuclei Concentration Relation to Aerosol Properties

    NASA Astrophysics Data System (ADS)

    DeMott, P. J.; Sullivan, R. C.; McMeeking, G.; Prenni, A. J.; Hill, T. C.; Franc, G. D.; Sullivan, A. P.; Garcia, E.; Tobo, Y.; Prather, K. A.; Suski, K.; Cazorla, A.; Anderson, J. R.; Kreidenweis, S. M.

    2011-12-01

    It is expected that atmospheric variability of ice nuclei concentrations is governed by a variety of factors related to aerosol physical and chemical properties. Not all particles contribute equally due to the special nature of ice nuclei. The "size requirement" of ice nuclei (Pruppacher and Klett, 1997), partly related to the typical aerosol compositions known to act as ice nuclei (e.g., mineral dust particles, certain biological particles), leads to the relation of ice nuclei number concentrations to larger aerosol concentrations in some cases, but we emphasize here the additional relation to aerosol chemistry. Recent atmospheric ice nuclei measurements focused on biomass burning, mineral dust, pollution and biological particles will be discussed to highlight new assessment of their source contributions on the basis of physical, chemical and biological analysis. Pruppacher, H. R., and J. D. Klett, 1997: Microphysics of Clouds and Precipitation (2nd Edition), Kluwer Academic Press, Dordrecht, 954 pp.

  20. Concentrations of iodine isotopes ((129)I and (127)I) and their isotopic ratios in aerosol samples from Northern Germany.

    PubMed

    Daraoui, A; Riebe, B; Walther, C; Wershofen, H; Schlosser, C; Vockenhuber, C; Synal, H-A

    2016-04-01

    New data about (129)I, (127)I concentrations and their isotopic ratios in aerosol samples from the trace survey station of the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Northern Germany, are presented and discussed in this paper. The investigated samples were collected on a weekly basis during the years 2011 to 2013. Iodine was extracted from aerosol filters using a strong basic solution and was separated from the matrix elements with chloroform and was analysed by accelerator mass spectrometry (AMS) for (129)I and by inductively coupled plasma mass spectrometry (ICP-MS) for (127)I. The concentrations of (127)I and (129)I in aerosol filters ranged from 0.31 to 3.71 ng m(-3) and from 0.06 to 0.75 fg m(-3), respectively. The results of (129)I/(127)I isotopic ratios were in the order 10(-8) to 10(-7). The (129)I originated directly from gaseous emissions and indirectly from liquid emissions (via sea spray) from the reprocessing plants in Sellafield and La Hague. In comparison with the results of (131)I after the Fukushima accident, no contribution of (129)I from this accident was detectable in Central Europe due to the high background originating from the (129)I releases of the European reprocessing plants. (129)I atmospheric activity concentrations were compared with those of an anthropogenic radionuclide ((85)Kr). We did not find any correlation between (129)I and (85)Kr, both having nuclear reprocessing plant as the main source.

  1. In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft

    NASA Astrophysics Data System (ADS)

    Wagner, N. L.; Brock, C. A.; Angevine, W. M.; Beyersdorf, A.; Campuzano-Jost, P.; Day, D.; de Gouw, J. A.; Diskin, G. S.; Gordon, T. D.; Graus, M. G.; Holloway, J. S.; Huey, G.; Jimenez, J. L.; Lack, D. A.; Liao, J.; Liu, X.; Markovic, M. Z.; Middlebrook, A. M.; Mikoviny, T.; Peischl, J.; Perring, A. E.; Richardson, M. S.; Ryerson, T. B.; Schwarz, J. P.; Warneke, C.; Welti, A.; Wisthaler, A.; Ziemba, L. D.; Murphy, D. M.

    2015-06-01

    Vertical profiles of submicron aerosol from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. These vertical profiles were collected over the southeastern United States (SEUS) during the summer of 2013 as part of two separate field studies: the Southeast Nexus (SENEX) study and the Study of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS). Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO). Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10 % larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA) were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD), was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10 % to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary aerosol aloft to explain the summertime enhancement of AOD (2-3 times greater than winter) over the southeastern United States. The first study attributes the layer aloft to secondary organic aerosol (SOA) while

  2. Using Raman-lidar-based regularized microphysical retrievals and Aerosol Mass Spectrometer measurements for the characterization of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Samaras, Stefanos; Nicolae, Doina; Böckmann, Christine; Vasilescu, Jeni; Binietoglou, Ioannis; Labzovskii, Lev; Toanca, Florica; Papayannis, Alexandros

    2015-10-01

    In this work we extract the microphysical properties of aerosols for a collection of measurement cases with low volume depolarization ratio originating from fire sources captured by the Raman lidar located at the National Institute of Optoelectronics (INOE) in Bucharest. Our algorithm was tested not only for pure smoke but also for mixed smoke and urban aerosols of variable age and growth. Applying a sensitivity analysis on initial parameter settings of our retrieval code was proved vital for producing semi-automatized retrievals with a hybrid regularization method developed at the Institute of Mathematics of Potsdam University. A direct quantitative comparison of the retrieved microphysical properties with measurements from a Compact Time of Flight Aerosol Mass Spectrometer (CToF-AMS) is used to validate our algorithm. Microphysical retrievals performed with sun photometer data are also used to explore our results. Focusing on the fine mode we observed remarkable similarities between the retrieved size distribution and the one measured by the AMS. More complicated atmospheric structures and the factor of absorption appear to depend more on particle radius being subject to variation. A good correlation was found between the aerosol effective radius and particle age, using the ratio of lidar ratios (LR: aerosol extinction to backscatter ratios) as an indicator for the latter. Finally, the dependence on relative humidity of aerosol effective radii measured on the ground and within the layers aloft show similar patterns.

  3. Vertical profile of elemental concentrations in aerosol particles in the Bermuda area during GCE/CASE/WATOX

    NASA Astrophysics Data System (ADS)

    Ennis, G.; Sievering, H.

    1990-06-01

    During the 1988 Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX) joint effort, research was conducted to determine elemental concentrations in atmospheric aerosol particles near Bermuda, to construct a three-level (15, 150, and 2600 m ASL) vertical profile of these concentrations, and to ascertain the source of the particles. Samples were collected by the NOAA King Air aircraft and NOAA ship Mt. Mitchell on July 24-28, 1988. Concentration determinations were made for 16 elements through the use of an X ray fluorescence instrument designed for analysis of small-mass samples. A layering effect was found; concentrations of several elements at 150 m were more than twice their respective concentrations at 15 m and 2600 m. Enrichment factors, V/Mn ratio, and correlations between concentrations suggest a Saharan mineral source, despite air mass back trajectories that show no direct continental input for up to 10 days prior to sample collection. Estimated total mineral aerosol concentrations at 15 m, 150 m, and 2600 m are 1.5, 4.1, and 2.1 μg m-3.

  4. Characterization of submicron aerosols during a serious pollution month in Beijing (2013) using an aerodyne high-resolution aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Zhang, J. K.; Sun, Y.; Liu, Z. R.; Ji, D. S.; Hu, B.; Liu, Q.; Wang, Y. S.

    2013-07-01

    In January 2013, Beijing experienced several serious haze events. To achieve a better understanding of the characteristics, sources and processes of aerosols during this month, an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed at an urban site between 1 January and 1 February 2013 to obtain the size-resolved chemical composition of non-refractory submicron particles (NR-PM1). During this period, the mean measured NR-PM1 mass concentration was 87.4 μg m-3 and was composed of organics (49.8%), sulfate (21.4%), nitrate (14.6%), ammonium (10.4%), and chloride (3.8%). Moreover, inorganic matter, such as sulfate and nitrate comprised an increasing fraction of the NR-PM1 load as NR-PM1 loading increased, denoting their key roles in particulate pollution during this month. The average size distributions of the species were all dominated by an accumulation mode peaking at approximately 600 nm in vacuum aerodynamic diameter and organics characterized by an additional smaller size (∼200 nm). Elemental analyses showed that the average O/C, H/C, and N/C (molar ratio) of organic matter were 0.34, 1.44 and 0.015, respectively, corresponding to an OM/OC ratio (mass ratio of organic matter to organic carbon) of 1.60. Positive matrix factorization (PMF) analyses of the high-resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., oxygenated organic aerosols (OOA), cooking-related (COA), nitrogen-containing (NOA) and hydrocarbon-like (HOA), which on average accounted for 40.0, 23.4, 18.1 and 18.5% of the total organic mass, respectively. Back trajectory clustering analyses indicated that the WNW air masses were associated with the highest NR-PM1 pollution during the campaign. Aerosol particles in southern air masses were especially rich in inorganic and oxidized organic species, whereas northern air masses contained a large fraction of primary species.

  5. DEVELOPMENTS IN DIRECT THERMAL EXTRACTION GAS CHROMATOGRAPHY-MASS SPECTROMETRY OF FINE AEROSOLS

    EPA Science Inventory

    This examines thermal extraction gas chromatography-mass spectrometry (TE/GC/MS) applied to aerosols collected on filters. Several different TE/GC/MS systems as a group have speciated hundreds of individual organic constituents in ambient fine aerosols. Molecular marker source ap...

  6. Aerosol properties and radiative forcing for three air masses transported in Summer 2011 to Sopot, Poland

    NASA Astrophysics Data System (ADS)

    Rozwadowska, Anna; Stachlewska, Iwona S.; Makuch, P.; Markowicz, K. M.; Petelski, T.; Strzałkowska, A.; Zieliński, T.

    2013-05-01

    Properties of atmospheric aerosols and solar radiation reaching the Earth's surface were measured during Summer 2011 in Sopot, Poland. Three cloudless days, characterized by different directions of incoming air-flows, which are typical transport pathways to Sopot, were used to estimate a radiative forcing due to aerosols present in each air mass.

  7. High aerosol acidity despite declining atmospheric sulfate concentrations over the past 15 years

    NASA Astrophysics Data System (ADS)

    Weber, Rodney J.; Guo, Hongyu; Russell, Armistead G.; Nenes, Athanasios

    2016-04-01

    Particle acidity affects aerosol concentrations, chemical composition and toxicity. Sulfate is often the main acid component of aerosols, and largely determines the acidity of fine particles under 2.5 μm in diameter, PM2.5. Over the past 15 years, atmospheric sulfate concentrations in the southeastern United States have decreased by 70%, whereas ammonia concentrations have been steady. Similar trends are occurring in many regions globally. Aerosol ammonium nitrate concentrations were assumed to increase to compensate for decreasing sulfate, which would result from increasing neutrality. Here we use observed gas and aerosol composition, humidity, and temperature data collected at a rural southeastern US site in June and July 2013 (ref. ), and a thermodynamic model that predicts pH and the gas-particle equilibrium concentrations of inorganic species from the observations to show that PM2.5 at the site is acidic. pH buffering by partitioning of ammonia between the gas and particle phases produced a relatively constant particle pH of 0-2 throughout the 15 years of decreasing atmospheric sulfate concentrations, and little change in particle ammonium nitrate concentrations. We conclude that the reductions in aerosol acidity widely anticipated from sulfur reductions, and expected acidity-related health and climate benefits, are unlikely to occur until atmospheric sulfate concentrations reach near pre-anthropogenic levels.

  8. Ultrahigh mass resolution and accurate mass measurements as a tool to characterize oligomers in secondary organic aerosols.

    PubMed

    Reinhardt, Alain; Emmenegger, Christian; Gerrits, Bertran; Panse, Christian; Dommen, Josef; Baltensperger, Urs; Zenobi, Renato; Kalberer, Markus

    2007-06-01

    Organic aerosols are a major fraction, often more than 50%, of the total atmospheric aerosol mass. The chemical composition of the total organic aerosol mass is poorly understood, although hundreds of compounds have been identified in the literature. High molecular weight compounds have recently gained much attention because this class of compounds potentially represents a major fraction of the unexplained organic aerosol mass. Here we analyze secondary organic aerosols, generated in a smog chamber from alpha-pinene ozonolysis with ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). About 450 compounds are detected in the mass range of m/z 200-700. The mass spectrum is clearly divided into a low molecular weight range (monomer) and a high molecular weight range, where dimers and trimers are distinguishable. Using the Kendrick mass analysis, the elemental composition of about 60% of all peaks could be determined throughout the whole mass range. Most compounds have high O:C ratios between 0.4 and 0.6. Small compounds (i.e., monomers) have a higher maximum O:C ratio than dimers and trimers, suggesting that condensation reactions with, for example, the loss of water are important in the oligomer formation process. A program developed in-house was used to determine exact mass differences between peaks in the monomer, dimer, and trimer mass range to identify potential monomer building blocks, which form the co-oligomers observed in the mass spectrum. A majority of the peaks measured in the low mass region of the spectrum (m/z < 300) is also found in the calculated results. For the first time the elemental composition of the majority of peaks over a wide mass range was determined using advanced data analysis methods for the analysis of ultra-high-resolution MS data. Possible oligomer formation mechanisms in secondary organic aerosols were investigated.

  9. New approach using lidar measurements to characterize spatiotemporal aerosol mass distribution in an underground railway station in Paris

    NASA Astrophysics Data System (ADS)

    Raut, J.-C.; Chazette, P.; Fortain, A.

    For the first time eye safe lidar measurements were performed at 355 nm simultaneously to in situ measurements in an underground station so as to test the potential interest of active remote sensing measurements to follow the spatiotemporal evolution of aerosol content inside such a confined microenvironment. The purpose of this paper is to describe different methods enabling the conversion of lidar-derived aerosol extinction coefficient into aerosol mass concentrations (PM 2.5 and PM 10). A theoretical method based on a well marked linear regression between mass concentrations simulated from the size distribution and extinction coefficients retrieved from Mie calculations provides averaged mass to optics' relations over the campaign for traffic (6.47 × 10 5 μg m -2) or no traffic conditions (3.73 × 10 5 μg m -2). Two empirical methods enable to significantly reduce CPU time. The first one is based upon the knowledge of size distribution measurements and scattering coefficients from nephelometer and allows retrieving mass to optics' relations for well determined periods or particular traffic conditions, like week-ends, with a good accuracy. The second method, that is more direct, is simply based on the ratio between TEOM concentrations and extinction coefficients obtained from nephelometer. This method is easy to set up but is not suitable for nocturnal measurements where PM stabilization time is short. Lidar signals thus converted into PM concentrations from those approaches with a fine accuracy (30%) provide a spatiotemporal distribution of concentrations in the station. This highlights aerosol accumulation in one side of the station, which can be explained by air displacement from the tunnel entrance. Those results allow expecting a more general use of lidar measurement to survey indoor air quality.

  10. Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) - Part 1: Fine particle composition and organic source apportionment

    SciTech Connect

    Aiken, A.C.; Wang, J.; Salcedo, D.; Cubison, M. J.; Huffman, J. A.; DeCarlo, P. F.; Ulbrich, I. M.; Docherty, K. S.; Sueper, D.; Kimmel, J. R.; Worsnop, D. R.; Trimborn, A.; Northway, M.; Stone, E. A.; Schauer, J. J.; Volkamer, R. M.; Fortner, E.; de Foy, B.; Laskin, A.; Shutthanandan, V.; Zheng, J.; Zhang, R.; Gaffney, J.; Marley, N. A.; Paredes-Miranda, G.; Arnott, W. P.; Molina, L. T.; Sosa, G.; Jimenez, J. L.

    2009-09-01

    Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identified three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning. A fourth OA component is a small local nitrogen-containing reduced OA component (LOA) which accounts for 9% of the OA mass but one third of the organic nitrogen, likely as amines. OOA accounts for almost half of the OA on average, consistent with previous observations. OA apportionment results from PMF-AMS are compared to the PM{sub 2.5} chemical mass balance of organic molecular markers (CMB-OMM, from GC/MS analysis of filters). Results from both methods are overall consistent. Both assign the major components of OA to primary urban, biomass burning/woodsmoke, and secondary sources at similar magnitudes. The 2006 Mexico City emissions inventory underestimates the urban primary PM{sub 2.5} emissions by a factor of {approx}4, and it is {approx}16 times lower than afternoon concentrations when secondary species are included. Additionally, the forest fire contribution is at least an order-of-magnitude larger than in the inventory.

  11. The importance of aerosol composition and mixing state on predicted CCN concentration and the variation of the importance with atmospheric processing of aerosol

    SciTech Connect

    Wang, J.; Cubison, M.; Aiken, A.; Jimenez, J.; Collins, D.; Gaffney, J.; Marley, N.

    2010-03-15

    The influences of atmospheric aerosols on cloud properties (i.e., aerosol indirect effects) strongly depend on the aerosol CCN concentrations, which can be effectively predicted from detailed aerosol size distribution, mixing state, and chemical composition using Köhler theory. However, atmospheric aerosols are complex and heterogeneous mixtures of a large number of species that cannot be individually simulated in global or regional models due to computational constraints. Furthermore, the thermodynamic properties or even the molecular identities of many organic species present in ambient aerosols are often not known to predict their cloud-activation behavior using Köhler theory. As a result, simplified presentations of aerosol composition and mixing state are necessary for large-scale models. In this study, aerosol microphysics, CCN concentrations, and chemical composition measured at the T0 urban super-site in Mexico City during MILAGRO are analyzed. During the campaign in March 2006, aerosol size distribution and composition often showed strong diurnal variation as a result of both primary emissions and aging of aerosols through coagulation and local photochemical production of secondary aerosol species. The submicron aerosol composition was ~1/2 organic species. Closure analysis is first carried out by comparing CCN concentrations calculated from the measured aerosol size distribution, mixing state, and chemical composition using extended Köhler theory to concurrent CCN measurements at five supersaturations ranging from 0.11% to 0.35%. The closure agreement and its diurnal variation are studied. CCN concentrations are also derived using various simplifications of the measured aerosol mixing state and chemical composition. The biases associated with these simplifications are compared for different supersaturations, and the variation of the biases is examined as a function of aerosol age. The results show that the simplification of internally mixed, size

  12. Aerosol properties associated with air masses arriving into the North East Atlantic during the 2008 Mace Head EUCAARI intensive observing period: an overview

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Ceburnis, D.; Martucci, G.; Bialek, J.; Dupuy, R.; Jennings, S. G.; Berresheim, H.; Wenger, J. C.; Sodeau, J. R.; Healy, R. M.; Facchini, M. C.; Rinaldi, M.; Giulianelli, L.; Finessi, E.; Worsnop, D.; O'Dowd, C. D.

    2009-12-01

    As part of the EUCAARI Intensive Observing Period, a 4-week campaign to measure aerosol physical, chemical and optical properties, atmospheric structure, and cloud microphysics was conducted from mid-May to mid-June 2008 at the Mace Head Atmospheric Research Station, located at the interface of Western Europe and the NE Atlantic and centered on the west Irish coastline. During the campaign, continental air masses comprising both young and aged continental plumes were encountered, along with polar, Arctic and tropical air masses. Polluted-continental aerosol concentrations were of the order of 3000 cm-3, while background marine air aerosol concentrations were between 400-600 cm-3. The highest marine air concentrations occurred in polar air masses in which a 15 nm nucleation mode, with concentration of 1100 cm-3, was observed and attributed to open ocean particle formation. Black carbon concentrations in polluted air were between 300-400 ng m-3, and in clean marine air were less than 50 ng m-3. Continental air submicron chemical composition (excluding refractory sea salt) was dominated by organic matter, closely followed by sulphate mass. Although the concentrations and size distribution spectral shape were almost identical for the young and aged continental cases, hygroscopic growth factors (GF) and cloud condensation nuclei (CCN) to total condensation nuclei (CN) concentration ratios were significantly less in the younger pollution plume, indicating a more oxidized organic component to the aged continental plume. The difference in chemical composition and hygroscopic growth factor appear to result in a 40-50% impact on aerosol scattering coefficients and Aerosol Optical Depth, despite almost identical aerosol microphysical properties in both cases, with the higher values been recorded for the more aged case. For the CCN/CN ratio, the highest ratios were seen in the more age plume. In marine air, sulphate mass dominated the sub-micron component, followed by water

  13. Overview of aerosol properties associated with air masses sampled by the ATR-42 during the EUCAARI campaign (2008)

    NASA Astrophysics Data System (ADS)

    Crumeyrolle, S.; Schwarzenboeck, A.; Sellegri, K.; Burkhart, J. F.; Stohl, A.; Gomes, L.; Quennehen, B.; Roberts, G.; Weigel, R.; Roger, J. C.; Villani, P.; Pichon, J. M.; Bourrianne, T.; Laj, P.

    2012-04-01

    Within the frame of the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) project the Météo-France aircraft ATR-42 performed 22 research flights, over central Europe and the North Sea during the intensive observation period in May 2008. For the campaign, the ATR-42 was equipped in order to study aerosol physical, chemical and optical properties, as well as cloud microphysics. During the campaign, continental air masses from Eastern and Western Europe were encountered, along with polar and Scandinavian air masses. For the 22 research flights, retroplume analyses along the flight tracks were performed with FLEXPART in order to classify air masses into five sectors of origin which allows for a qualitative evaluation of emission influence on the respective air parcel. In the polluted boundary layer (BL), typical concentrations of particles with diameters larger than 10 nm (N10) are of the order of 5000-6000 cm-3, whereas N10 concentrations of clean air masses were lower than 1300 cm-3. The detection of the largest particle number concentrations occurred in air masses coming from Polar and Scandinavian regions for which an elevated number of nucleation mode (25-28 nm) particles was observed and attributed to new particle formation over open sea. In the free troposphere (FT), typical observed N10 are of the order of 900 cm-3 in polluted air masses and 400-600 cm-3 in clean air masses, respectively. In both layers, the chemical composition of submicron aerosol particles is dominated by organic matter and nitrate in polluted air masses, while, sulphate and ammonium followed by organics dominate the submicron aerosols in clean air masses. The highest CCN/CN ratios were observed within the polar air masses while the CCN concentration values are the highest within the polluted air masses. Within the five air mass sectors defined and the two layers (BL and FT), observations have been distinguished into anticyclonic (first half of May 2008) and cyclonic

  14. Fractal morphology, imaging and mass spectrometry of single aerosol particles in flight (CXIDB ID 16)

    SciTech Connect

    Loh, N. Duane

    2012-06-20

    This deposition includes the aerosol diffraction images used for phasing, fractal morphology, and time-of-flight mass spectrometry. Files in this deposition are ordered in subdirectories that reflect the specifics.

  15. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Chan, A. W. H.; Chan, M. N.; Surratt, J. D.; Chhabra, P. S.; Loza, C. L.; Crounse, J. D.; Yee, L. D.; Flagan, R. C.; Wennberg, P. O.; Seinfeld, J. H.

    2010-08-01

    Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C4-unsaturated aldehyde) under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO2) formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios (3-8), the SOA yields from isoprene high-NOx photooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  16. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Chan, A. W. H.; Chan, M. N.; Surratt, J. D.; Chhabra, P. S.; Loza, C. L.; Crounse, J. D.; Yee, L. D.; Flagan, R. C.; Wennberg, P. O.; Seinfeld, J. H.

    2010-04-01

    Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C4-unsaturated aldehyde) under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(O)OONO2) formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios, the SOA yields from isoprene high-NOxphotooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  17. Effect of stratospheric aerosols on direct sunlight and implications for concentrating solar power.

    PubMed

    Murphy, Daniel M

    2009-04-15

    Light scattering calculations and data show that stratospheric aerosols reduce direct sunlight by about 4 W for every watt reflected to outer space. The balance becomes diffuse sunlight. One consequence of deliberate enhancement of the stratospheric aerosol layer would be a significant reduction in the efficiency of solar power generation systems using parabolic or other concentrating optics. There also would be a reduction in the effectiveness of passive solar design.

  18. The Role of Atmospheric Aerosol Concentration on Deep Convective Precipitation: Cloud-resolving Model Simulations

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Li, X.; Khain, A.; Mastsui, T.; Lang, S.; Simpson, J.

    2007-01-01

    Aerosols and especially their effect on clouds are one of the key components of the climate system and the hydrological cycle [Ramanathan et al., 20011. Yet, the aerosol effect on clouds remains largely unknown and the processes involved not well understood. A recent report published by the National Academy of Science states "The greatest uncertainty about the aerosol climate forcing - indeed, the largest of all the uncertainties about global climate forcing - is probably the indirect effect of aerosols on clouds NRC [2001]." The aerosol effect on clouds is often categorized into the traditional "first indirect (i.e., Twomey)" effect on the cloud droplet sizes for a constant liquid water path and the "semi-direct" effect on cloud coverage. The aerosol effect on precipitation processes, also known as the second type of aerosol indirect effect, is even more complex, especially for mixed-phase convective clouds. ln this paper, a cloud-resolving model (CRM) with detailed spectral-bin microphysics was used to examine the effect of aerosols on three different deep convective cloud systems that developed in different geographic locations: South Florida, Oklahoma and the Central Pacific. In all three cases, rain reaches the ground earlier for the low CCN (clean) case. Rain suppression is also evident in all three cases with high CCN (dirty) case. However, this suppression only occurs during the first hour of the simulations. During the mature stages of the simulations, the effects of increasing aerosol concentration range from rain suppression in the Oklahoma case, to almost no effect in the Florida case, to rain enhancement in the Pacific case. These results show the complexity of aerosol interactions with convection.

  19. Comparison of POLDER Derived Aerosol Optical Thickness to Surface Monitor Fine Particle Concentration

    NASA Astrophysics Data System (ADS)

    Leon, J.; Kacenelenbogen, M.; Chiapello, I.

    2005-12-01

    The Particulate Matter (PM) mass measured at the ground level is a common way to quantify the amount of aerosol particles in the atmosphere and is used as a standard to evaluate air quality. Satellite remote sensing is well suited for a daily monitoring of the aerosol load. However, there are no straightforward relationship between aerosol optical properties derived from the satellite sensor and the PM mass at the ground. This paper is focused on the use of Polarization and Directionality of Earth's Reflectance (POLDER-2) derived aerosol optical thickness (AOT) for the monitoring of PM2.5. We present a correlation study between PM2.5 data collected in the frame of the French Environmental protection agency, aerosol optical properties derived from Sun photometer measurements, and POLDER derived-AOT over the land. POLDER AOT retrieval algorithm over the land is based on the use of the measurement of the linear polarized light in the 670 nm and 865 nm channels. We show that only the fine fraction (below 0.3 μm) of the aerosol size distribution contributes to the signal in polarization and then to the POLDER derived-AOT and then is well suited for monitoring of fine particle. The correlation between POLDER AOT and PM2.5 is significant (R between 0.6 and 0.7) over several sites. We present a tentative evaluation of Air Quality Categories from satellite data.

  20. Characterization of a Quadrotor Unmanned Aircraft System for Aerosol-Particle-Concentration Measurements.

    PubMed

    Brady, James M; Stokes, M Dale; Bonnardel, Jim; Bertram, Timothy H

    2016-02-02

    High-spatial-resolution, near-surface vertical profiling of atmospheric chemical composition is currently limited by the availability of experimental platforms that can sample in constrained environments. As a result, measurements of near-surface gradients in trace gas and aerosol particle concentrations have been limited to studies conducted from fixed location towers or tethered balloons. Here, we explore the utility of a quadrotor unmanned aircraft system (UAS) as a sampling platform to measure vertical and horizontal concentration gradients of trace gases and aerosol particles at high spatial resolution (1 m) within the mixed layer (0-100 m). A 3D Robotics Iris+ autonomous quadrotor UAS was outfitted with a sensor package consisting of a two-channel aerosol optical particle counter and a CO2 sensor. The UAS demonstrated high precision in both vertical (±0.5 m) and horizontal positions (±1 m), highlighting the potential utility of quadrotor UAS drones for aerosol- and trace-gas measurements within complex terrain, such as the urban environment, forest canopies, and above difficult-to-access areas such as breaking surf. Vertical profiles of aerosol particle number concentrations, acquired from flights conducted along the California coastline, were used to constrain sea-spray aerosol-emission rates from coastal wave breaking.

  1. Aerosol properties associated with air masses arriving into the North East Atlantic during the 2008 Mace Head EUCAARI intensive observing period: an overview

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Ceburnis, D.; Martucci, G.; Bialek, J.; Dupuy, R.; Jennings, S. G.; Berresheim, H.; Wenger, J.; Healy, R.; Facchini, M. C.; Rinaldi, M.; Giulianelli, L.; Finessi, E.; Worsnop, D.; Ehn, M.; Mikkilä, J.; Kulmala, M.; O'Dowd, C. D.

    2010-09-01

    As part of the EUCAARI Intensive Observing Period, a 4-week campaign to measure aerosol physical, chemical and optical properties, atmospheric structure, and cloud microphysics was conducted from mid-May to mid-June, 2008 at the Mace Head Atmospheric Research Station, located at the interface of Western Europe and the N. E. Atlantic and centered on the west Irish coastline. During the campaign, continental air masses comprising both young and aged continental plumes were encountered, along with polar, Arctic and tropical air masses. Polluted-continental aerosol concentrations were of the order of 3000 cm-3, while background marine air aerosol concentrations were between 400-600 cm-3. The highest marine air concentrations occurred in polar air masses in which a 15 nm nucleation mode, with concentration of 1100 cm-3, was observed and attributed to open ocean particle formation. Continental air submicron chemical composition (excluding refractory sea salt) was dominated by organic matter, closely followed by sulphate mass. Although the concentrations and size distribution spectral shape were almost identical for the young and aged continental cases, hygroscopic growth factors (GF) and cloud condensation nuclei (CCN) to total condensation nuclei (CN) concentration ratios were significantly less in the younger pollution plume, indicating a more oxidized organic component to the aged continental plume. The difference in chemical composition and hygroscopic growth factor appear to result in a 40-50% impact on aerosol scattering coefficients and Aerosol Optical Depth, despite almost identical aerosol microphysical properties in both cases, with the higher values been recorded for the more aged case. For the CCN/CN ratio, the highest ratios were seen in the more age plume. In marine air, sulphate mass dominated the sub-micron component, followed by water soluble organic carbon, which, in turn, was dominated by methanesulphonic acid (MSA). Sulphate concentrations were

  2. 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 ...

  3. New mass measurement method of aerosol particle using vibrating probe particle controlled by radiation pressure

    NASA Astrophysics Data System (ADS)

    Hariyama, Tatsuo; Takaya, Yasuhiro; Miyoshi, Takashi

    2005-11-01

    Aerosol particles with sub-micro meter size inhaled into respiratory systems cause serious damage to human body. In order to evaluate the health effects of the particles, classification methods of the particles with size and mass are needed. Several measurement methods of the particle size are established. However, conventional mass measurement methods are not enough to measure the particles with sub- pico gram. We propose a new mass measurement method of the aerosol particles based on laser trapping. In this method, an optically trapped silica particle is used as a measuring probe particle. The probe particle is trapped at a beam waist of the focused laser light and is forced to vibrate by deflecting the beam waist using AOD. The vibrating probe particle has a resonance frequency because it is governed by the spring-mass-damper system. When an aerosol particle is attached to the probe particle, the resonance frequency shifts according to the increase of the total mass. The mass of the aerosol particle can be measured from the shift of the resonance frequency. Experimentally, it is confirmed that the probe particle is governed by the spring-mass-damper system and has a resonance frequency. When a silica fine particle of 3pg in mass used as an aerosol particle is attached to the probe particle, the resonance frequency shift occurs as expected in the dynamic system and the fine particle mass can be measured based on the proposed method.

  4. Relationships among particle number, surface area, and respirable mass concentrations in automotive engine manufacturing.

    PubMed

    Heitbrink, William A; Evans, Douglas E; Ku, Bon Ki; Maynard, Andrew D; Slavin, Thomas J; Peters, Thomas M

    2009-01-01

    This study investigated the relationships between particle number, surface area, and respirable mass concentration measured simultaneously in a foundry and an automotive engine machining and assembly center. Aerosol concentrations were measured throughout each plant with a condensation particle counter for number concentration, a diffusion charger for active surface area concentration, and an optical particle counter for respirable mass concentration. At selected locations, particle size distributions were characterized with the optical particle counter and an electrical low pressure impactor. Statistical analyses showed that active surface area concentration was correlated with ultrafine particle number concentration and weakly correlated with respirable mass concentration. Correlation between number and active surface area concentration was stronger during winter (R2 = 0.6 for both plants) than in the summer (R2 = 0.38 and 0.36 for the foundry and engine plant respectively). The stronger correlation in winter was attributed to use of direct-fire gas fired heaters that produced substantial numbers of ultrafine particles with a modal diameter between 0.007 and 0.023 mu m. These correlations support findings obtained through theoretical analysis. Such analysis predicts that active surface area increasingly underestimates geometric surface area with increasing particle size, particularly for particles larger than 100 nm. Thus, a stronger correlation between particle number concentration and active surface area concentration is expected in the presence of high concentrations of ultrafine particles. In general, active surface area concentration may be a concentration metric that is distinct from particle number concentration and respirable mass concentration. For future health effects or toxicological studies involving nano-materials or ultrafine aerosols, this finding needs to be considered, as exposure metrics may influence data interpretation.

  5. Chemical composition, sources, and processes of urban aerosols during summertime in northwest China: insights from high-resolution aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Xu, J.; Zhang, Q.; Chen, M.; Ge, X.; Ren, J.; Qin, D.

    2014-12-01

    An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed along with a scanning mobility particle sizer (SMPS) and a multi-angle absorption photometer (MAAP) to measure the temporal variations of the mass loading, chemical composition, and size distribution of submicron particulate matter (PM1) in Lanzhou, northwest China, during 11 July-7 August 2012. The average (PM1 mass concentration including non-refractory (PM1 (NR-(PM1) measured by HR-ToF-AMS and black carbon (BC) measured by MAAP during this study was 24.5 μg m-3 (ranging from 0.86 to 105 μg m-3), with a mean composition consisting of 47% organics, 16% sulfate, 12% BC, 11% ammonium, 10% nitrate, and 4% chloride. Organic aerosol (OA) on average consisted of 70% carbon, 21% oxygen, 8% hydrogen, and 1% nitrogen, with the average oxygen-to-carbon ratio (O / C) of 0.33 and organic mass-to-carbon ratio (OM / OC) of 1.58. Positive matrix factorization (PMF) of the high-resolution organic mass spectra identified four distinct factors which represent, respectively, two primary OA (POA) emission sources (traffic and food cooking) and two secondary OA (SOA) types - a fresher, semi-volatile oxygenated OA (SV-OOA) and a more aged, low-volatility oxygenated OA (LV-OOA). Traffic-related hydrocarbon-like OA (HOA) and BC displayed distinct diurnal patterns, both with peak at ~ 07:00-11:00 (BJT: UTC +8), corresponding to the morning rush hours, while cooking-emission related OA (COA) peaked during three meal periods. The diurnal profiles of sulfate and LV-OOA displayed a broad peak between ~ 07:00 and 15:00, while those of nitrate, ammonium, and SV-OOA showed a narrower peak between ~ 08:00-13:00. The later morning and early afternoon maximum in the diurnal profiles of secondary aerosol species was likely caused by downward mixing of pollutants aloft, which were likely produced in the residual layer decoupled from the boundary layer during nighttime. The mass spectrum of SV-OOA was

  6. 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.

  7. 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.

  8. 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.

  9. Variability of aerosol, gaseous pollutants and meteorological characteristics associated with changes in air mass origin at the SW Atlantic coast of Iberia

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

    2012-04-01

    Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean, a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol (NR-PM1) was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition, small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions, could be identified in the particle phase

  10. Simultaneous retrieval of aerosol optical thickness and chlorophyll concentration from multiwavelength measurement over East China Sea

    NASA Astrophysics Data System (ADS)

    Shi, Chong; Nakajima, Teruyuki; Hashimoto, Makiko

    2016-12-01

    A flexible inversion algorithm is proposed for simultaneously retrieving aerosol optical thickness (AOT) and surface chlorophyll a (Chl) concentration from multiwavelength observation over the ocean. In this algorithm, forward radiation calculation is performed by an accurate coupled atmosphere-ocean model with a comprehensive bio-optical ocean module. Then, a full-physical nonlinear optimization approximation approach is used to retrieve AOT and Chl. For AOT retrieval, a global three-dimensional spectral radiation-transport aerosol model is used as the a priori constraint to increase the retrieval accuracy of aerosol. To investigate the algorithm's availability, the retrieval experiment is conducted using simulated radiance data to demonstrate that the relative errors in simultaneously determining AOT and Chl can be mostly controlled to within 10% using multiwavelength and angle covering in and out of sunglint. Furthermore, the inversion results are assessed using the actual satellite observation data obtained from Cloud and Aerosol Imager (CAI)/Greenhouse gas Observation SATellite GOSAT and MODerate resolution Imaging Spectroradiometer (MODIS)/Aqua instruments through comparison to Aerosol Robotic Network (AERONET) aerosol and ocean color (OC) products over East China Sea. Both the retrieved AOT and Chl compare favorably to the reported AERONET values, particularly when using the CASE 2 ocean module in turbid water, even when the retrieval is performed in the presence of high aerosol loading and sunglint. Finally, the CAI and MODIS images are used to jointly retrieve the spatial distribution of AOT and Chl in comparison to the MODIS AOT and OC products.

  11. Influence of the external mixing state of atmospheric aerosol on derived CCN number concentrations

    NASA Astrophysics Data System (ADS)

    Wex, H.; McFiggans, G.; Henning, S.; Stratmann, F.

    2010-05-01

    We derived the range of particle hygroscopicities ($\\kappa$) that occurs in the atmosphere, based on literature data of measured hygroscopic growth or based on chemical composition. The derived $\\kappa$-values show that the atmospheric aerosol often is an external mixture with respect to hygroscopicity. Mean $\\kappa$ were derived for urban, rural, and marine aerosols for the different hygroscopic modes. Using these $\\kappa$ and exemplary particle number size distributions for the different aerosols, the number concentration of cloud condensation nuclei (NCCN) was derived for two cases, (1) accounting for the less hygroscopic fraction of particles and (2) assuming all particles to have $\\kappa$ of the more hygroscopic mode. NCCN derived from measured particle hygroscopicity is overestimated for case (2). Overestimation of NCCN is largest for fresh continental aerosol and less pronounced for marine aerosol. With $\\kappa$ derived from bulk aerosol composition data, only the hygroscopicity of more soluble aerosol particles is captured. Bulk or even size-resolved composition data will be insufficient to predict NCCN under many conditions unless independent information about particle mixing state is available.

  12. Size and mass distributions of ground-level sub-micrometer biomass burning aerosol from small wildfires

    NASA Astrophysics Data System (ADS)

    Okoshi, Rintaro; Rasheed, Abdur; Chen Reddy, Greeshma; McCrowey, Clinton J.; Curtis, Daniel B.

    2014-06-01

    Biomass burning emits large amounts of aerosol particles globally, influencing human health and climate, but the number and size of the particles is highly variable depending on fuel type, burning and meteorological conditions, and secondary reactions in the atmosphere. Ambient measurements of aerosol during wildfire events can therefore improve our understanding of particulate matter produced from biomass burning. In this study, time-resolved sub-micrometer ambient aerosol size and mass distributions of freshly emitted aerosol were measured for three biomass burning wildfire events near Northridge, California, located in the highly populated San Fernando Valley area of Los Angeles. One fire (Marek) was observed during the dry Santa Ana conditions that are typically present during large Southern California wildfires, but two smaller fires (Getty and Camarillo) were observed during the more predominant non-Santa Ana weather conditions. Although the fires were generally small and extinguished quickly, they produced particle number concentrations as high as 50,000 cm-3 and mass concentrations as large as 150 μg cm-3, well above background measurements and among the highest values observed for fires in Southern California. Therefore, small wildfires can have a large impact on air quality if they occur near urban areas. Particle number distributions were lognormal, with peak diameters in the accumulation mode at approximately 100 nm. However, significant Aitken mode and nucleation mode particles were observed in bimodal distributions for one fire. Significant variations in the median diameter were observed over time, as particles generally became smaller as the fires were contained. The results indicate that it is likely that performing mass measurements alone could systematically miss detection of the smaller particles and size measurements may be better suited for studies of ambient biomass burning events. Parameters of representative unimodal and bimodal lognormal

  13. Mass Spectrometric Analysis of Pristine Aerosol Particles During the wet Season of Amazonia - Detection of Primary Biological Particles?

    NASA Astrophysics Data System (ADS)

    Schneider, J.; Zorn, S. R.; Freutel, F.; Borrmann, S.; Chen, Q.; Farmer, D. K.; Jimenez, J. L.; Flores, M.; Roldin, P.; Artaxo, P.; Martin, S. T.

    2008-12-01

    The contribution of primary biological aerosol (POA) particles to the natural organic aerosol is a subject of current research. Estimations of the POA contribution to the total aerosol particle concentration range between 25 and 80%, depending on location and season. Especially in the tropical rain forest it is expected that POA is a major source of supermicron, possibly also of submicron particles. During AMAZE (Amazonian Aerosol CharacteriZation Experiment), a field project near Manaus, Brazil, in February/March 2008, an Aerodyne ToF-AMS was equipped with a high pressure aerodynamic lens. This high pressure lens (operating pressure 14.6 torr) is designed with the objective to extend the detectable size range of the AMS into the supermicron size range where primary biological particles are expected. Size distribution measured by the AMS were compared with size distribution from an optical particle counter and indicate that the high pressure lens has a 50% cut-off at a vacuum aerodynamic diameter of about 1 μm, but still has significant transmission up to a vacuum aerodynamic diameter of about 2 μm, thus extending the detectable size range of the AMS into the coarse mode. The measuring instruments were situated in a container at ground level. The aerosol was sampled through a 40 m vertical, laminar inlet, which was heated and dried to maintain a relative humidity between 30 and 40%. The inlet was equipped with a 7 μm cut-off cyclone. Size distributions recorded with an optical particle counter parallel to the AMS show that the inlet transmitted aerosol particles up to an optically detected diameter of 10 μm. POA particles like plant fragments, pollen, spores, fungi, viruses etc. contain chemical compounds as proteins, sugars, amino acids, chlorophyll, and cellular material as cellulose. Laboratory experiments have been performed in order to identify typical mass spectral patterns of these compounds. These laboratory data were compared to size resolved particle

  14. Determination of aromatic tracer compounds for environmental tobacco smoke aerosol by two step laser mass spectrometry

    NASA Astrophysics Data System (ADS)

    Morrical, Brad D.; Zenobi, Renato

    Cigarette smoking is a major cause of indoor aerosol pollution. Determination of exposure to environmental tobacco smoke (ETS) aerosol is critical to understanding health effects. Sizing studies have shown that ETS has a size distribution that is efficiently deposited into the lungs and can therefore provide effective delivery of carcinogenic compounds into the human body. Two-step laser mass spectrometry is used to analyze aromatic compounds on aerosols collected from a smoking lobby. The determination and suitability of ETS tracers on aerosols is examined. Additionally, the transport of aerosol from the smoking lobby is examined to determine what effect deposition and dilution have on the mass spectrum observed. Results from the analysis of ETS, both from lobby samples and direct cigarette sampling, show that several unique peaks are present in the mass spectrum when compared to other combustion sources, such as automobiles and diesel trucks. In particular, ions at m/ z 118, 132, 146, and 160 are consistently present and are not found in other combustion sources. For the indoor environment, where chemical transformation is much less rapid than in the outdoor environment, these ions were found to be present as soon as the first smokers appeared and persisted over the course of the day. Aerosol samples taken in the morning prior to the presence of smokers in the lobby reveal the presence of skeletal PAHs, indicative of outdoor urban traffic aerosol penetration into the building.

  15. Mass spectrometric approaches for chemical characterisation of atmospheric aerosols: critical review of the most recent advances

    SciTech Connect

    Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A.

    2012-06-29

    This manuscript presents an overview of the most recent instrument developments for the field and laboratory applications of mass spectrometry (MS) to investigate the chemistry and physics of atmospheric aerosols. A range of MS instruments, employing different sample introduction methods, ionisation and mass detection techniques are used both for ‘online’ and ‘offline’ characterisation of aerosols. Online MS techniques enable detection of individual particles with simultaneous measurement of particle size distributions and aerodynamic characteristics and are ideally suited for field studies that require high temporal resolution. Offline MS techniques provide a means for detailed molecular-level analysis of aerosol samples, which is essential to gain fundamental knowledge regarding aerosol chemistry, mechanisms of particle formation and atmospheric aging. Combined, complementary MS techniques provide comprehensive information on the chemical composition, size, morphology and phase of aerosols – data of key importance for evaluating hygroscopic and optical properties of particles, their health effects, understanding their origins and atmospheric evolution. Over the last few years, developments and applications of MS techniques in aerosol research have expanded remarkably as evident by skyrocketing publication statistics. Finally, the goal of this review is to present the most recent developments in the field of aerosol mass spectrometry for the time period of late 2010 to early 2012, which have not been conveyed in previous reviews.

  16. Aerosol effects on ozone concentrations in Beijing: a model sensitivity study.

    PubMed

    Xu, Jun; Zhang, Yuanhang; Zheng, Shaoqing; He, Youjiang

    2012-01-01

    Most previous O3 simulations were based only on gaseous phase photochemistry. However, some aerosol-related processes, namely, heterogeneous reactions occurring on the aerosol surface and photolysis rate alternated by aerosol radiative influence, may affect O3 photochemistry under high aerosol loads. A three-dimensional air quality model, Models-3/Community Multi-scale Air Quality-Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution, was employed to simulate the effects of the above-mentioned processes on O3 formation under typical high O3 episodes in Beijing during summer. Five heterogeneous reactions, i.e., NO2, NO3, N2O5, HO2, and O3, were individually investigated to elucidate their effects on 03 formation. The results showed that the heterogeneous reactions significantly affected O3 formation in the urban plume. NO2 heterogeneous reaction increased O3 to 90 ppb, while HO2 heterogeneous reaction decreased O3 to 33 ppb. In addition, O3 heterogeneous loss decreased O3 to 31 ppb. The effects of NO2, NO3, and N2O5 heterogeneous reactions showed opposite O3 concentration changes between the urban and extra-urban areas because of the response of the reactions to the two types of O3 formation regimes. When the aerosol radiative influence was included, the photolysis rate decreased and O3 decreased significantly to 73 ppb O3. The two aerosol-related processes should be considered in the study of O3 formation because high aerosol concentration is a ubiquitous phenomenon that affects the urban- and regional air quality in China.

  17. Effect of Vaporizer Temperature on Ambient Non-Refractory Submicron Aerosol Composition and Mass Spectra Measured by the Aerosol Mass Spectrometer

    EPA Science Inventory

    Aerodyne Aerosol Mass Spectrometers (AMS) are routinely operated with a constant vaporizer temperature (Tvap) of 600oC in order to facilitate quantitative detection of non-refractory submicron (NR-PM1) species. By analogy with other thermal desorption instrument...

  18. Real-time analysis of ambient organic aerosols using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    NASA Astrophysics Data System (ADS)

    Brüggemann, Martin; Karu, Einar; Stelzer, Torsten; Hoffmann, Thorsten

    2015-04-01

    Organic aerosol accounts for a major fraction of atmospheric aerosols and has implications on the earth's climate and human health. However, due to the chemical complexity its measurement remains a major challenge for analytical instrumentation.1 Here, we present the development, characterization and application of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in ambient aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source utilizes a helium glow discharge plasma to produce excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and results mainly in intact molecular ions, facilitating the interpretation of the acquired mass spectra. In the past, similar approaches were used to detect pesticides, explosives or illicit drugs on a variety of surfaces.2,3 In contrast, the AeroFAPA source operates 'online' and allows the detection of organic compounds in aerosols without a prior precipitation or sampling step. To our knowledge, this is the first application of an atmospheric-pressure glow discharge ionization technique to ambient aerosol samples. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng-m-3 range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region in Central Europe is presented. Several oxidation products of monoterpenes were clearly identified using the possibility to perform tandem MS experiments. The acquired data are in agreement with previous studies and demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis. Furthermore, these results reveal the potential of this technique to enable new insights into aerosol formation, growth and transformation in the atmosphere. References: 1) IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The

  19. On-line analysis of urban particulate matter focusing on elevated wintertime aerosol concentrations.

    PubMed

    Tan, Phillip V; Evans, Greg J; Tsai, Julia; Owega, Sandy; Fila, Michael S; Malpica, Oscar; Brook, Jeffrey R

    2002-08-15

    A 10-day winter sampling campaign was conducted in downtown Toronto for particulate matter (PM) air pollution in the fine (<2.5 microm) size range. An aerosol laser ablation mass spectrometer (LAMS), a tapered-element oscillating microbalance (TEOM), and an aerodynamic particle sizer (APS) were operated in parallel to characterize the PM on-line. In this study, the LAMS observed differences in the chemical composition between three separate episodes with higher PM2.5 mass and APS counts. LAMS results showed that in one instance of elevated PM, organic amines were present in the particulates. Temporal analyses of this episode revealed chemical transformations as the amines, characterized by m/z peaks 58(C3HeN)+, 86(C5H2N)+, and nitrates, increased in number concentration while Ca and hydrocarbon particle classes concurrently decreased. On another day, sulfates were found to have increased significantly. The third event was only 4 h in duration and exhibited an increase in the number of submicron-sized K/hydrocarbons and sulfate-containing particles. In this last event, the hydrocarbons and a K to Fe ratio enrichment indicated there was likely a contribution from a combustion source. This work offers some of the first insights into single particle size and chemistry in a cold winter climate.

  20. Progress Toward a Global, EOS-Era Aerosol Air Mass Type Climatology

    NASA Technical Reports Server (NTRS)

    Kahn, Ralph A.

    2012-01-01

    The MISR and MODIS instruments aboard the NASA Earth Observing System's Terra Satellite have been collecting data containing information about the state of Earth's atmosphere and surface for over eleven years. Data from these instruments have been used to develop a global, monthly climatology of aerosol amount that is widely used as a constraint on climate models, including those used for the 2007 IPCC assessment report. The next frontier in assessing aerosol radiative forcing of climate is aerosol type, and in particular, the absorption properties of major aerosol air masses. This presentation will focus on the prospects for constraining aerosol type globally, and the steps we are taking to apply a combination of satellite and suborbital data to this challenge.

  1. OMI tropospheric NO2 air mass factors over South America: effects of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; Torres, O.; de Haan, J. F.

    2015-03-01

    Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2) to the atmosphere. OMI observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospheric columns due to the radiative effects of aerosols, especially light-absorbing carbonaceous aerosols, are not well understood. It has been shown that the O2-O2 effective cloud fraction and pressure retrieval is sensitive to aerosol optical and physical properties, including aerosol optical depth (AOD). Aerosols implicitly influence the tropospheric air mass factor (AMF) calculations used in the NO2 retrieval through the effective cloud parameters used in the independent pixel approximation. In this work, we explicitly account for the effects of biomass burning aerosols in the tropospheric NO2 AMF calculation by including collocated aerosol extinction vertical profile observations from the CALIOP instrument, and aerosol optical depth (AOD) and single scattering albedo (SSA) retrieved by the OMI near-UV aerosol algorithm (OMAERUV) in the DISAMAR radiative transfer model for cloud-free scenes. Tropospheric AMFs calculated with DISAMAR were benchmarked against AMFs reported in the Dutch OMI NO2 (DOMINO) retrieval; the mean and standard deviation (SD) of the difference was 0.6 ± 8%. Averaged over three successive South American biomass burning seasons (2006-2008), the spatial correlation in the 500 nm AOD retrieved by OMI and the 532 nm AOD retrieved by CALIOP was 0.6, and 72% of the daily OMAERUV AOD observations were within 0.3 of the CALIOP observations. Overall, tropospheric AMFs calculated with observed aerosol parameters were on average 10% higher than AMFs calculated with effective cloud parameters. For effective cloud radiance fractions less than 30%, or effective cloud pressures greater than 800 hPa, the difference between tropospheric AMFs based on implicit and explicit aerosol parameters is on average 6 and 3

  2. Aerosols and gases concentrations observed at Stelvio National Park (Italian Alps) during summer conditions

    NASA Astrophysics Data System (ADS)

    Landi, T. C.; Marinoni, A.; Cristofanelli, P.; Bonafè, U.; Calzolari, F.; Duchi, R.; Laj, P.; Villani, P.; Bonasoni, P.

    2012-04-01

    Three summer fields campaigns were carried out during 2009, 2010 and 2011 in two sites in the area of Stelvio National Park (SNP), Central Italian Alps. Those activities were performed in the frame of the SHARE - Stelvio project (Station at High Altitude for Research on the Environment). SNP includes an extensive impervious territory of valleys and high mountains, up to 3900 m asl. Two high altitude sampling sites, Rifugio Guasti (3285 m asl) and Forni glacier ( 2700 m asl), have been picked out for collecting the main atmospheric parameters: the first site hosted the field campaign in 2009 and 2010 and was located at Cevedale pass, at the border between Lombardia and Trentino-Alto Adige regions, while in 2011 the measurements were carried out on Forni glacier surface, in a N-S oriented valley, through SHARE-box, a portable and autonomous unit for atmospheric measurements developed in the framework of SHARE project. Because of different location Rifugio Guasti is an ideal site to monitor long range transport on Southern slope of Alpine range, while Forni glacier is more affected by local influence of valley and glacier breezes. Monitored parameters concerned (i) meteorology, such as air temperature, relative humidity, wind speed and direction, air pressure, (ii) chemical and physical properties of the aerosols (number concentrations, size distribution and chemical composition) and (iii) , gases concentration (CO2, O3). This work is aimed at describing the behaviour of these compounds, in terms of concentration observed over different time scales, such hourly and daily, in order to investigate the impact of transport processes (i.e. air masses transports arisen from both "thermal" breezes or synoptic circulation) on aerosols and gases variability at SNP. The Alps face the Po Valley, one of the more populated and industrialized region in Europe. This is one of the most probable source of polluted air masses which spread towards high altitude sites, such as Alps and

  3. Carbonaceous particles and aerosol mass closure in PM2.5 collected in a port city

    NASA Astrophysics Data System (ADS)

    Genga, A.; Ielpo, P.; Siciliano, T.; Siciliano, M.

    2017-01-01

    Mass concentrations of PM2.5, mineral dust, organic carbon (OC) and elemental carbon (EC), water-soluble organic carbon (WSOC), sea salts and anthropogenic metals have been studied in a city-port of south Italy (Brindisi). This city is characterized by different emission sources (ship, vehicular traffic, biomass burning and industrial emissions) and it is an important port and industrial site of the Adriatic sea. Based on diagnostic ratios of carbonaceous species we assess the presence of biomass burning emissions (BBE), fossil fuel emissions (FFE) and ship emission (SE). Our proposed conversion factors from OC to OM are higher than those reported in the literature for urban site: the reason of this could be due to the existence of aged combustion aerosols during the sampling campaign (WSOC/OC = 0.6 ± 0.3).

  4. [Concentration distribution of metal elements in atmospheric aerosol under different weather conditions in Qingdao Coastal Region].

    PubMed

    Chen, Xiao-Jing; Qi, Jian-Hua; Liu, Ning; Zhang, Xiang-Yu; Shen, Heng-Qing; Liu, Ming-Xu

    2014-10-01

    To know the influence of different weather conditions on the concentration of metal elements in aerosols in the coastal region, total suspended particles (TSP) samples were collected from April to May 2012, and August 2012 to March 2013 in the Qingdao coastal region, and common trace metals were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results showed that Al, Ca, Fe, Na, K and Mg were the dominant metal elements in TSP, and the sum of the six elements accounted for 94.2% of the sum of all metals. TSP and metal elements had significant monthly variations, Fe, Al, K, Ca, Mg, Zn, Ba, Mn, Ti, Sr and Li had the highest concentration in November and January, while Be, Sc, Co, Ni and Cr showed the highest value in January. Na had the highest concentration in August, November and February, and the lowest in December. Pb had the highest concentration in January and February, and the lowest in August and December. Enrichment factors indicated that Be, Co, Al, Ca, Fe, K, Mg, Mn, Sr and Ti were mainly affected by natural sources; Li, Cr, Ni, Zn, Ba and Na were affected by natural sources and part of anthropogenic sources; Pb was mainly from anthropogenic sources. Different weather conditions had great impact on TSP and metal elements concentrations, all the measured metals had the highest concentrations in smog except Ti. Compared with the sunny day, the concentration of atmospheric particulate Ti decreased, while the other elements increased by 1 to 4 times in smog. Li, Be, Cr, Ni, Al, Fe, Mg and Mn had little variation in concentration in foggy day, and the concentration of Pb and Na increased considerably. The concentration of Co, Ca and Ti reduced obviously in fog. Except for Cr, Co and Ti, the other elements increased by 1 to 3 times in haze. Most of the elements had the minimal enrichment factors in sunny day, while the other had the maximal enrichment factor in

  5. Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior

    SciTech Connect

    UC Davis; Cappa, Christopher D.; Wilson, Kevin R.

    2010-10-28

    Vacuum Ultraviolet (VUV) photoionization mass spectrometry has been used to measure the evolution of chemical composition for two distinct organic aerosol types as they are passed through a thermodenuder at different temperatures. The two organic aerosol types considered are primary lubricating oil (LO) aerosol and secondary aerosol from the alpha-pinene + O3 reaction (alphaP). The evolution of the VUV mass spectra for the two aerosol types with temperature are observed to differ dramatically. For LO particles, the spectra exhibit distinct changes with temperature in which the lower m/z peaks, corresponding to compounds with higher vapor pressures, disappear more rapidly than the high m/z peaks. In contrast, the alphaP aerosol spectrum is essentially unchanged by temperature even though the particles experience significant mass loss due to evaporation. The variations in the LO spectra are found to be quantitatively in agreement with expectations from absorptive partitioning theory whereas the alphaP spectra suggest that the evaporation of alphaP derived aerosol appears to not be governed by partitioning theory. We postulate that this difference arises from the alphaP particles existing as in a glassy state instead of having the expected liquid-like behavior. To reconcile these observations with decades of aerosol growth measurements, which indicate that OA formation is described by equilibrium partitioning, we present a conceptual model wherein the secondary OA is formed and then rapidly converted from an absorbing form to a non-absorbing form. The results suggest that although OA growth may be describable by equilibrium partitioning theory, the properties of organic aerosol once formed may differ significantly from the properties determined in the equilibrium framework.

  6. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall.

    PubMed

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; Kuang, Chongai; Barbosa, Henrique M J; Brito, Joel; Carbone, Samara; Chi, Xuguang; Comstock, Jennifer; Ditas, Florian; Lavric, Jost; Manninen, Hanna E; Mei, Fan; Moran-Zuloaga, Daniel; Pöhlker, Christopher; Pöhlker, Mira L; Saturno, Jorge; Schmid, Beat; Souza, Rodrigo A F; Springston, Stephen R; Tomlinson, Jason M; Toto, Tami; Walter, David; Wimmer, Daniela; Smith, James N; Kulmala, Markku; Machado, Luiz A T; Artaxo, Paulo; Andreae, Meinrat O; Petäjä, Tuukka; Martin, Scot T

    2016-11-17

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin (for example, ref. 2) and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- and ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. This rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.

  7. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; Kuang, Chongai; Barbosa, Henrique M. J.; Brito, Joel; Carbone, Samara; Chi, Xuguang; Comstock, Jennifer; Ditas, Florian; Lavric, Jost; Manninen, Hanna E.; Mei, Fan; Moran-Zuloaga, Daniel; Pöhlker, Christopher; Pöhlker, Mira L.; Saturno, Jorge; Schmid, Beat; Souza, Rodrigo A. F.; Springston, Stephen R.; Tomlinson, Jason M.; Toto, Tami; Walter, David; Wimmer, Daniela; Smith, James N.; Kulmala, Markku; Machado, Luiz A. T.; Artaxo, Paulo; Andreae, Meinrat O.; Petäjä, Tuukka; Martin, Scot T.

    2016-11-01

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin (for example, ref. 2) and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- and ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. This rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.

  8. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

    SciTech Connect

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; Kuang, Chongai; Barbosa, Henrique M. J.; Brito, Joel; Carbone, Samara; Chi, Xuguang; Comstock, Jennifer; Ditas, Florian; Lavric, Jost; Manninen, Hanna E.; Mei, Fan; Moran-Zuloaga, Daniel; Pöhlker, Christopher; Pöhlker, Mira L.; Saturno, Jorge; Schmid, Beat; Souza, Rodrigo A. F.; Springston, Stephen R.; Tomlinson, Jason M.; Toto, Tami; Walter, David; Wimmer, Daniela; Smith, James N.; Kulmala, Markku; Machado, Luiz A. T.; Artaxo, Paulo; Andreae, Meinrat O.; Petäjä, Tuukka; Martin, Scot T.

    2016-10-24

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- and ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. Lastly, this rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.

  9. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

    DOE PAGES

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; ...

    2016-10-24

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- andmore » ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. Lastly, this rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.« less

  10. Calculations of relative optical air masses for various aerosol types and minor gases in Arctic and Antarctic atmospheres

    NASA Astrophysics Data System (ADS)

    Tomasi, Claudio; Petkov, Boyan H.

    2014-02-01

    The dependence functions of relative optical air mass on apparent solar zenith angle θ have been calculated over the θ < 87° range for the vertical profiles of wet-air molecular number density in the Arctic and Antarctic atmospheres, extinction coefficients of different aerosol types, and molecular number density of water vapor, ozone, nitrogen dioxide, and oxygen dimer. The calculations were made using as weight functions the seasonal average vertical profiles of (i) pressure and temperature derived from multiyear sets of radiosounding measurements performed at Ny-Ålesund, Alert, Mario Zucchelli, and Neumayer stations; (ii) volume extinction coefficients of background summer aerosol, Arctic haze, and Kasatochi and Pinatubo volcanic aerosol measured with lidars or balloon-borne samplings; and (iii) molecular number concentrations of the above minor gases, derived from radiosonde, ozonesonde, and satellite-based observations. The air mass values were determined using a formula based on a realistic atmospheric air-refraction model. They were systematically checked by comparing their mutual differences with the uncertainties arising from the seasonal and daily variations in pressure and temperature conditions within the various ranges, where aerosol and gases attenuate the solar radiation most efficiently. The results provide evidence that secant-approximated and midlatitude air mass values are inappropriate for analyzing the Sun photometer measurements performed at polar sites. They indicate that the present evaluations can be reliably used to estimate the aerosol optical depth from the Arctic and Antarctic measurements of total optical depth, after appropriate corrections for the Rayleigh scattering and gaseous absorption optical depths.

  11. Aerosol Chemistry Resolved by Mass Spectrometry: Linking Field Measurements of Cloud Condensation Nuclei Activity to Organic Aerosol Composition.

    PubMed

    Vogel, Alexander L; Schneider, Johannes; Müller-Tautges, Christina; Phillips, Gavin J; Pöhlker, Mira L; Rose, Diana; Zuth, Christoph; Makkonen, Ulla; Hakola, Hannele; Crowley, John N; Andreae, Meinrat O; Pöschl, Ulrich; Hoffmann, Thorsten

    2016-10-06

    Aerosol hygroscopic properties were linked to its chemical composition by using complementary online mass spectrometric techniques in a comprehensive chemical characterization study at a rural mountaintop station in central Germany in August 2012. In particular, atmospheric pressure chemical ionization mass spectrometry ((-)APCI-MS) provided measurements of organic acids, organosulfates, and nitrooxy-organosulfates in the particle phase at 1 min time resolution. Offline analysis of filter samples enabled us to determine the molecular composition of signals appearing in the online (-)APCI-MS spectra. Aerosol mass spectrometry (AMS) provided quantitative measurements of total submicrometer organics, nitrate, sulfate, and ammonium. Inorganic sulfate measurements were achieved by semionline ion chromatography and were compared to the AMS total sulfate mass. We found that up to 40% of the total sulfate mass fraction can be covalently bonded to organic molecules. This finding is supported by both on- and offline soft ionization techniques, which confirmed the presence of several organosulfates and nitrooxy-organosulfates in the particle phase. The chemical composition analysis was compared to hygroscopicity measurements derived from a cloud condensation nuclei counter. We observed that the hygroscopicity parameter (κ) that is derived from organic mass fractions determined by AMS measurements may overestimate the observed κ up to 0.2 if a high fraction of sulfate is bonded to organic molecules and little photochemical aging is exhibited.

  12. Production Mechanism, Number Concentration, Size Distribution, Chemical Composition, and Optical Properties of Sea Spray Aerosols Workshop, Summer 2012

    SciTech Connect

    Meskhidze, Nicholas

    2013-10-21

    The objective of this workshop was to address the most urgent open science questions for improved quantification of sea spray aerosol-radiation-climate interactions. Sea spray emission and its influence on global climate remains one of the most uncertain components of the aerosol-radiation-climate problem, but has received less attention than other aerosol processes (e.g. production of terrestrial secondary organic aerosols). Thus, the special emphasis was placed on the production flux of sea spray aerosol particles, their number concentration and chemical composition and properties.

  13. Ultrahigh resolution mass spectrometric characterization of organic aerosol from European and Chinese cities

    NASA Astrophysics Data System (ADS)

    Wang, Kai; Huang, Ru-Jin; Hoffmann, Thorsten

    2016-04-01

    Organic aerosol constitutes a substantial fraction (20-90%) of submicrometer aerosol mass, playing an important role in air quality and human health. Over the past few years, ultra-high resolution mass spectrometry (UHRMS) has been applied to elucidate the chemical composition of ambient aerosols. However, most of the UHRMS studies used direct infusion without prior separation by liquid chromatography, which may cause the loss of individual compound information and interference problems. In the present study, urban ambient aerosol with particle diameter < 2.5 μm was collected in Mainz, Germany and Beijing, China, respectively. Two pretreatment procedures were applied to extract the organic compounds from the filter samples: One method uses a mixture of acetonitrile and water, the other uses pure water and prepared for the extraction of humic-like substances. The extracts were analyzed by ultra-high-performance liquid chromatography coupled with an Orbitrap mass spectrometer in both negative and the positive modes. The effects of pretreatment procedures on the characterization of organic aerosol and the city-wise difference in chemical composition of organic aerosol will be discussed in detail.

  14. n-Alkanoic monocarboxylic acid concentrations in urban and rural aerosols: Seasonal dependence and major sources

    NASA Astrophysics Data System (ADS)

    Shannigrahi, Ardhendu S.; Pettersson, Jan B. C.; Langer, Sarka; Arrhenius, Karine; Hagström, Magnus; Janhäll, Sara; Hallquist, Mattias; Pathak, Ravi Kant

    2014-06-01

    We report new data on the abundance and distribution of n-monocarboxylic acids (n-MCAs) in fine- and coarse-mode aerosols in rural and urban areas of Sweden, and determine their possible sources. Overall, C6-C16n-MCAs accounted for ~ 0.5-1.2% of the total PM10 (particulate matter ≤ 10 μm) mass. In general, the C12-C16 fraction was the most abundant (> 75%), with the exception of wintertime samples from a rural site, where C6-C11 acids accounted for 65% of the total C6-C16n-MCA mass. Positive matrix factorization analysis revealed four major sources of n-MCAs: traffic emissions, wood combustion, microbial activity, and a fourth factor that was dominated by semi-volatile n-MCAs. Traffic emissions were important in the urban environment in both seasons and at the rural site during winters, and were a major source of C9-C11 acids. Wood combustion was a significant source at urban sites during the winter and also to some extent at the rural site in both seasons. This is consistent with the use of wood for domestic heating but may also be related to meat cooking. Thus, during the winter, traffic, wood combustion and microbial activity were all important sources in the urban environment, while traffic was the dominant source at the rural site. During the summer, there was considerable day-to-day variation in n-MCA concentrations but microbial activity was the dominant source. The semi-volatile low molecular weight C6-C8 acids accounted for a small (~ 5-10%) fraction of the total mass of n-MCAs. This factor is unlikely to be linked to a single source and its influence instead reflects the partitioning of these compounds between the gas and particle phases. This would explain their greater contribution during the winter.

  15. On the Implications of aerosol liquid water and phase separation for modeled organic aerosol mass

    EPA Science Inventory

    Current chemical transport models assume that organic aerosol (OA)-forming compounds partition mostly to a water-poor, organic-rich phase in accordance with their vapor pressures. However, in the southeast United States, a significant fraction of ambient organic compounds are wat...

  16. AEROSOL CONCENTRATIONS DURING THE 1999 FRESNO EXPOSURE STUDIES AS FUNCTIONS OF SIZE, SEASON, AND METEOROLOGY

    EPA Science Inventory

    The 1999 Fresno exposure studies took place in February (winter season) and April/May (spring season) for two periods of four weeks. During that time, nearly-continuous measurements of outdoor aerosol concentrations were made with a scanning mobility spectrometer (TSI SNIPS) an...

  17. Origin of atmospheric aerosols at the Pierre Auger Observatory using studies of air mass trajectories in South America

    NASA Astrophysics Data System (ADS)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bardenet, R.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Foerster, N.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giammarchi, M.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kadija, K.; Kambeitz, O.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Pontz, M.; Porcelli, A.; Preda, T.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Thao, N. T.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Curci, G.

    2014-11-01

    The Pierre Auger Observatory is making significant contributions towards understanding the nature and origin of ultra-high energy cosmic rays. One of its main challenges is the monitoring of the atmosphere, both in terms of its state variables and its optical properties. The aim of this work is to analyse aerosol optical depth τa(z) values measured from 2004 to 2012 at the observatory, which is located in a remote and relatively unstudied area of Pampa Amarilla, Argentina. The aerosol optical depth is in average quite low - annual mean τa(3.5 km) ∼ 0.04 - and shows a seasonal trend with a winter minimum - τa(3.5 km) ∼ 0.03 -, and a summer maximum - τa(3.5 km) ∼ 0.06 -, and an unexpected increase from August to September - τa(3.5 km) ∼ 0.055. We computed backward trajectories for the years 2005 to 2012 to interpret the air mass origin. Winter nights with low aerosol concentrations show air masses originating from the Pacific Ocean. Average concentrations are affected by continental sources (wind-blown dust and urban pollution), whilst the peak observed in September and October could be linked to biomass burning in the northern part of Argentina or air pollution coming from surrounding urban areas.

  18. Criteria for significance of simultaneous presence of both condensible vapors and aerosol particles on mass transfer (deposition) rates

    NASA Technical Reports Server (NTRS)

    Gokoglu, S. A.

    1987-01-01

    The simultaneous presence of aerosol particles and condensible vapors in a saturated boundary layer which may affect deposition rates to subcooled surfaces because of vapor-particle interactions is discussed. Scavenging of condensible vapors by aerosol particles may lead to increased particle size and decreased vapor mass fraction, which alters both vapor and particle deposition rates. Particles, if sufficiently concentrated, may also coagulate. Criteria are provided to assess the significance of such phenomena when particles are already present in the mainstream and are not created inside the boundary layer via homogeneous nucleation. It is determined that there is direct proportionality with: (1) the mass concentration of both condensible vapors and aerosol particles; and (2) the square of the boundary layer thickness to particle diameter ratio (delta d sub p) square. Inverse proportionality was found for mainstream to surface temperature difference if thermophoresis dominates particle transport. It is concluded that the square of the boundary layer thickness to particle diameter ratio is the most critical factor to consider in deciding when to neglect vapor-particle interactions.

  19. Criteria for significance of simultaneous presence of both condensible vapors and aerosol particles on mass transfer (deposition) rates

    NASA Technical Reports Server (NTRS)

    Gokoglu, S. A.

    1986-01-01

    The simultaneous presence of aerosol particles and condensible vapors in a saturated boundary layer which may affect deposition rates to subcooled surfaces because of vapor-particle interactions is discussed. Scavenging of condensible vapors by aerosol particles may lead to increased particle size and decreased vapor mass fraction, which alters both vapor and particle deposition rates. Particles, if sufficiently concentrated, may also coagulate. Criteria are provided to assess the significance of such phenomena when particles are already present in the mainstream and are not created inside the boundary layer via homogeneous nucleation. It is determined that there is direct proportionality with: (1) the mass concentration of both condensible vapors and aerosol particles; and (2) the square of the boundary layer thickness to particle diameter ratio (delta d sub p) square. Inverse proportionality was found for mainstream to surface temperature difference if thermophoresis dominates particle transport. It is concluded that the square of the boundary layer thickness to particle diameter ratio is the most critical factor to consider in deciding when to neglect vapor-particle interactions.

  20. Evaluation Of Sensitivity Of Mass-independent Oxygen Isotopes In Aerosol Nitrate To Environmental Factors Using A Photochemical Box Model

    NASA Astrophysics Data System (ADS)

    Dominguez, G.; Wilkins, G.; Jackson, T.; Brothers, L.; McCabe, J.; Thiemens, M. H.

    2007-12-01

    An existing photochemical box model for use in polluted marine boundary layers was modified to allow for the explicit tracking of the mass-independent isotopic composition of oxygen in aerosol nitrate as well as other atmospheric species such as OH and H2O2. This modified model was then used to study the sensitivity of the mass-independent isotopic composition of atmospheric nitrate(HNO3) to variables such as relative humidity, temperature ozone and NOx concentrations. Here we present the results of these studies and compare model predictions of the mass-independent oxygen isotopic composition of aerosol nitrate to measurements taken in fine (<1micron) and coarse (>1 micron) aerosol samples taken in a variety of locations, from coastal urban environments, the tropics (Ecuador), inland California (Riverside), and Antarctica. Regarding Antarctica, we comment on the isotopic composition of OH there and the ramifications of these findings for the isotopic composition of other oxygen bearing compounds in the Antarctic atmosphere.

  1. The Role of Atmospheric Aerosol Concentration on Deep Convective Precipitation: Cloud-Resolving Model Simulations

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Li, Xiaowen; Khain, Alexander; Matsui, Toshihisa; Lang, Stephen; Simpson, Joanne

    2010-01-01

    Aerosols and especially their effect on clouds are one of the key components of the climate system and the hydrological cycle [Ramanathan et al., 2001]. Yet, the aerosol effect on clouds remains largely unknown and the processes involved not well understood. A recent report published by the National Academy of Science states "The greatest uncertainty about the aerosol climate forcing - indeed, the largest of all the uncertainties about global climate forcing - is probably the indirect effect of aerosols on clouds NRC [2001]." The aerosol effect on Clouds is often categorized into the traditional "first indirect (i.e., Twomey)" effect on the cloud droplet sizes for a constant liquid water path and the "semi-direct" effect on cloud coverage. The aerosol effect on precipitation processes, also known as the second type of aerosol indirect effect, is even more complex, especially for mixed-phase convective clouds. In this paper, a cloud-resolving model (CRM) with detailed spectral-bin microphysics was used to examine the effect of aerosols on three different deep convective cloud systems that developed in different geographic locations: South Florida, Oklahoma and the Central Pacific, In all three cases, rain reaches the ground earlier for the low CCN (clean) case. Rain suppression is also evident in all three cases with high CCN (dirty) case. However, this suppression only occurs during the first hour of the simulations. During the mature stages of the simulations, the effects of increasing aerosol concentration range from rain suppression in the Oklahoma case, to almost no effect in the Florida case, to rain enhancement in the Pacific case. These results show the complexity of aerosol interactions with convection. The model results suggest that evaporative cooling is a key process in determining whether high CCN reduces or enhances precipitation. Stronger evaporative cooling can produce a stronger cold pool and thus stronger low-level convergence through interactions

  2. Submicron aerosol analysis and organic source apportionment in an urban atmosphere in Pearl River Delta of China using high-resolution aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    He, Ling-Yan; Huang, Xiao-Feng; Xue, Lian; Hu, Min; Lin, Yun; Zheng, Jun; Zhang, Renyi; Zhang, Yuan-Hang

    2011-06-01

    The Pearl River Delta (PRD) region in South China is one of the most economically developed regions in China while also noted for its severe air pollution, especially in the urban environments. In order to understand in depth the aerosol chemistry and the emission sources in PRD, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed at an urban site in the Hong Kong-Shenzhen metropolitan area between 25 October and 2 December 2009. Ten minute-resolved measurement data were analyzed, and an average mass concentration of 44.5 ± 34.0 μg m-3 was calculated for the entire campaign. On average, organic matter was the most abundant PM1 component accounting for 39.7% of the total mass, followed by sulfate (24.5%), black carbon (measured by aethalometer, 14.0%), ammonium (10.2%), nitrate (10.0%), and chloride (1.6%). Moreover, organic matter comprised an increasing fraction of the PM1 loading as the PM1 loading increased, denoting its key role in particulate pollution in this region. Calculations of organic elemental composition based on the high-resolution organic mass spectra obtained indicated that C, H, O, and N on average contributed 33.8%, 55.1%, 10.2%, and 0.9%, respectively, to the total atomic numbers of organic aerosol (OA), which corresponded to an OM/OC ratio (the ratio of organic matter mass/organic carbon mass) of 1.57 ± 0.08. Positive matrix factorization analysis was then conducted on the high-resolution organic mass spectral data set. Four OA components were identified, including a hydrocarbon-like (HOA), a biomass burning (BBOA), and two oxygenated (LV-OOA and SV-OOA) components, which on average accounted for 29.5%, 24.1%, 18.8%, and 27.6%, respectively, of the total organic mass. The HOA was found to have contributions from both fossil fuel combustion and cooking emissions, while the BBOA was well correlated with acetonitrile, a known biomass burning marker. The LV-OOA and SV-OOA corresponded to more aged and

  3. Aerosol mass size distribution and black carbon over a high altitude location in Western Trans-Himalayas: Impact of a dust episode

    NASA Astrophysics Data System (ADS)

    Kompalli, Sobhan Kumar; Krishna Moorthy, K.; Suresh Babu, S.; Manoj, M. R.

    2014-12-01

    The information on the aerosol properties from remote locations provides insights into the background and natural conditions against which anthropogenic impacts could be compared. Measurements of the near surface aerosol mass size distribution from the high altitude remote site help us to understand the natural processes, such as, the association between Aeolian and fluvial processes that have a direct bearing on the mass concentrations, especially in the larger size ranges. In the present study, the total mass concentration and mass-size distribution of the near surface aerosols, measured using a 10-channel Quartz Crystal Microbalance (QCM) Impactor from a high altitude location-Hanle (32.78°N, 78.95°E, 4520 m asl) in the western Trans-Himalayas, have been used to characterize the composite aerosols. Also the impact of a highly localized, short-duration dust storm episode on the mass size distribution has been examined. In general, though the total mass concentration (Mt) remained very low (∼0.75 ± 0.61 μg m-3), interestingly, coarse mode (super-micron) aerosols contributed almost 72 ± 6% to the total aerosol mass loading near the surface. The mass-size distribution showed 3 modes, a fine particle mode (∼0.2 μm), an accumulation mode at ∼0.5 μm, and a coarse mode at ∼3 μm. During a localized short duration dust storm episode, Mt reached as high as ∼13.5 μg m-3 with coarse mode aerosols contributing to nearly 90% of it. The mass size distribution changed significantly, with a broad coarse mode so that the accumulation mode became inconspicuous. Concurrent measurements of aerosol black carbon (BC) using twin wavelength measurements of the aethalometer showed an increase in the wavelength index of absorption, from the normal values of ∼1 to 1.5 signifying the enhanced absorption at the short wavelength (380 nm) by the dust.

  4. A rocket-borne mass analyzer for charged aerosol particles in the mesosphere

    SciTech Connect

    Knappmiller, Scott; Robertson, Scott; Sternovsky, Zoltan; Friedrich, Martin

    2008-10-15

    An electrostatic mass spectrometer for nanometer-sized charged aerosol particles in the mesosphere has been developed and tested. The analyzer is mounted on the forward end of a rocket and has a slit opening for admitting a continuous sample of air that is exhausted through ports at the sides. Within the instrument housing are two sets of four collection plates that are biased with positive and negative voltages for the collection of negative and positive aerosol particles, respectively. Each collection plate spans about an order of magnitude in mass which corresponds to a factor of 2 in radius. The number density of the charge is calculated from the current collected by the plates. The mean free path for molecular collisions in the mesosphere is comparable to the size of the instrument opening; thus, the analyzer performance is modeled by a Monte Carlo computer code that finds the aerosol particles trajectories within the instrument including both the electrostatic force and the forces from collisions of the aerosol particles with air molecules. Mass sensitivity curves obtained using the computer models are near to those obtained in the laboratory using an ion source. The first two flights of the instrument returned data showing the charge number densities of both positive and negative aerosol particles in four mass ranges.

  5. Chemical composition of Titan's aerosols analogues characterized with a systematic pyrolysis-gas chromatography-mass spectrometry characterization

    NASA Astrophysics Data System (ADS)

    Szopa, Cyril; Raulin, Francois; Coll, Patrice; Cabane, Michel; GCMS Team

    2014-05-01

    The in situ chemical characterization of Titan's atmosphere was achieved in 2005 with two instruments present onboard the Huygens atmospheric probe : the Aerosol Collector and Pyrolyzer (ACP) devoted to collect and pyrolyse Titan's aerosols ; the Gas Chromatograph-Mass Spectrometer (GCMS) experiment devoted to analyze gases collected in the atmosphere or coming from the aerosols pyrolysis. The GCMS was developed by Hasso Niemann in the filiation of the quadrupole mass spectrometers he built for several former space missions. The main objectives were to : determine the concentration profile of the most abundant chemical species; seek for minor atmospheric organic species not detected with remote observations ; give a first view of the organic aerosols structure; characterize the condensed volatiles present at the surface (e.g. lakes) in case of survival of the probe to the landing impact. Taking into account for the potential complexity of the gaseous samples to be analyzed, it was decided to couple to the MS analyzer a gas chromatograph capable to separate volatile species from light inorganic molecules and noble gases, to organic compounds including aromatics. This was the first GCMS analyzer that worked in an extraterrestrial environment since the Viking missions on Mars. Even if the GCMS coupling mode did not provide any result of interest, it has been demonstrated to be functional during the Huygens descent. But, the direct MS analysis of the atmosphere, and the pyrolysis-MS analysis of aerosols allowed to make great discoveries which are still of primary importance to describe the Titan's lower atmosphere composition. This contribution aims at presenting this instrument that worked in the Titan's atmosphere, and summarizing the most important discoveries it allowed.

  6. Effects of climate change on aerosol concentrations in Europe

    NASA Astrophysics Data System (ADS)

    Megaritis, Athanasios G.; Fountoukis, Christos; Pandis, Spyros N.

    2013-04-01

    High concentrations of particulate matter less than 2.5 μm in size (PM2.5), ozone and other major constituents of air pollution, have adverse effects on human health, visibility and ecosystems (Seinfeld and Pandis, 2006), and are strongly influenced by meteorology. Emissions control policy is currently made assuming that climate will remain constant in the future. However, climate change over the next decades is expected to be significant (IPCC, 2007) and may impact local and regional air quality. Determining the sensitivity of the concentrations of air pollutants to climate change is an important step toward estimating future air quality. In this study we applied PMCAMx (Fountoukis et al., 2011), a three dimensional chemical transport model, over Europe, in order to quantify the individual effects of various meteorological parameters on fine particulate matter (PM2.5) concentrations. A suite of perturbations in various meteorological factors, such as temperature, wind speed, absolute humidity and precipitation were imposed separately on base case conditions to determine the sensitivities of PM2.5 concentrations and composition to these parameters. Different simulation periods (summer, autumn 2008 and winter 2009) are used to examine also the seasonal dependence of the air quality - climate interactions. The results of these sensitivity simulations suggest that there is an important link between changes in meteorology and PM2.5 levels. We quantify through separate sensitivity simulations the processes which are mainly responsible for the final predicted changes in PM2.5 concentration and composition. The predicted PM2.5 response to those meteorology perturbations was found to be quite variable in space and time. These results suggest that, the changes in concentrations caused by changes in climate should be taken into account in long-term air quality planning. References Fountoukis C., Racherla P. N., Denier van der Gon H. A. C., Polymeneas P., Charalampidis P. E

  7. Concentration characteristics of bromine and iodine in aerosols in Shanghai, China

    NASA Astrophysics Data System (ADS)

    Gao, Yunchuan; Sun, Mingxing; Wu, Xiaowei; Liu, Yongdi; Guo, Yaqi; Wu, Ji

    2010-11-01

    Aerosol samples (TSP and PM 10) during each season were collected at a national monitoring point in Shanghai in 2008. Halogens (Br, I) were determined in samples along with sodium (Na) by ICP-MS and ICP-OES after microwave digestion. In this report we focused on the concentration characteristics of halogen elements Br and I and their seasonal distributions. The mean annual concentrations of total Br and I were 24 ng m -3 and 12 ng m -3 for TSP, 21 ng m -3 and 9 ng m -3 for PM 10, respectively. Concentrations of Br and I in TSP and PM 10 were lowest in summer but an increase occurred in autumn and winter. Water-soluble Br and I accounted for about 32% of the total Br and I in aerosols, and about 68% of Br and I was non soluble which may be non-soluble organic species. These non-soluble organic species are present in aerosols in the possible binding forms as mineral dust, natural organic matter, and adsorption to black carbon or mineral material such as iron oxides. Soluble Br and I in PM 10 extracted by a dilute acid solution (HNO 3 + H 2SO 4) increased by 22% and 18%, respectively, compared with water-soluble Br and I. A positive correlation with Na and sea water enrichment factors for Br and I indicated that bromine and iodine in aerosols originated mostly from marine sources in Shanghai.

  8. Anthropogenic sources of aerosol particles in a football stadium: Real-time characterization of emissions from cigarette smoking, cooking, hand flares, and color smoke bombs by high-resolution aerosol mass spectrometry

    NASA Astrophysics Data System (ADS)

    Faber, Peter; Drewnick, Frank; Veres, Patrick R.; Williams, Jonathan; Borrmann, Stephan

    2013-10-01

    Aerosol particles from several anthropogenic sources associated with football stadia including cooking, cigarette smoking, burning of color smoke bombs and hand flares were analyzed by high-resolution aerosol mass spectrometry. The physical and chemical characteristics of these different aerosols, in particular the organic fraction, were explored in laboratory studies to obtain robust references. These data were compared with field campaign results from a Bundesliga (German football league) match in the Coface Arena (Mainz, Germany) on 20th April 2012. The field measurement revealed a strongly elevated mass concentration of organic aerosols (OA) compared to background levels showing a temporal structure clearly related to the match. PMF analysis established that during the football match event cigarette smoke was the predominant component of submicron organic aerosol (67% of total OA). Cooking emissions from food outlets within the stadium correlated well with the sales figures of the catering stations and were also found to be of relevance (24% of total OA) especially in the period before kickoff. Pyrotechnics were not observed during this football match and no signatures of these sources were found in the mass spectra from the stadium measurements. All species that were elevated during the football match returned to their initial background levels within one hour after the match had finished. This demonstrates a good ventilation capacity of the open-topped Coface Arena.

  9. Aircraft observations of aerosol and trace gas concentrations in the tropical troposphere up to 12 km during the INCA campaign

    NASA Astrophysics Data System (ADS)

    Minikin, A.; Baehr, J.; Krejci, R.; Schlager, H.; van Velthoven, P.; Seifert, M.; Ström, J.; Petzold, A.; Schumann, U.

    2003-04-01

    During the EU funded project INCA (Interhemispheric differences in cirrus properties from anthropogenic emissions) the DLR Falcon 20, a German research aircraft with a maximum ceiling of 13~km, carried out measurements of aerosol and trace gas concentrations during transfer from Europe to South America and back in order to obtain meridional cross sections between 50^o~N and 50^o~S. At tropical latitudes the southbound transfer flights were directed along the west coast of South America, whereas the northbound transfer flights passed over Brazil and the central Atlantic Ocean. We report on observational data of number concentrations of Aitken and accumulation mode particles, the fractionation between volatile and non-volatile particles, as well as mixing ratios of carbon monoxide, reactive nitrogen species and ozone. In the tropics aerosol number concentrations above 9~km altitude increase by one order of magnitude, if compared to the sub-tropics and mid-latitudes, most pronounced for refractory particles. These elevated aerosol concentrations occur where 3-dimensional back trajectories originate from the central South American continent (Amazon basin) and have undergone systematic uplifting. The very high fraction of refractory particles, up to 50--60~% of total condensation nuclei, may indicate a strong contribution of continental ground sources. The INCA measurements confirm earlier TROPOZ II observations of an extended upper tropospheric layer of enhanced CO and NO over tropical South America during the wet season. Vertical distributions show a striking increase of CO mixing ratios above 6~km. Corresponding increases of NO and NOy and decreases of ozone were also found. During INCA an anticyclonic flow over tropical South America was persistent in the upper troposphere. This upper-level anticyclone is associated with intense convective activity over the Amazon basin and redistributes the convectively lifted air masses over a large area in the tropical middle

  10. Effects of turbulence on mixed-phase deep convective clouds under different basic-state winds and aerosol concentrations

    NASA Astrophysics Data System (ADS)

    Lee, Hyunho; Baik, Jong-Jin; Han, Ji-Young

    2014-12-01

    The effects of turbulence-induced collision enhancement (TICE) on mixed-phase deep convective clouds are numerically investigated using a 2-D cloud model with bin microphysics for uniform and sheared basic-state wind profiles and different aerosol concentrations. Graupel particles account for the most of the cloud mass in all simulation cases. In the uniform basic-state wind cases, graupel particles with moderate sizes account for some of the total graupel mass in the cases with TICE, whereas graupel particles with large sizes account for almost all the total graupel mass in the cases without TICE. This is because the growth of ice crystals into small graupel particles is enhanced due to TICE. The changes in the size distributions of graupel particles due to TICE result in a decrease in the mass-averaged mean terminal velocity of graupel particles. Therefore, the downward flux of graupel mass, and thus the melting of graupel particles, is reduced due to TICE, leading to a decrease in the amount of surface precipitation. Moreover, under the low aerosol concentration, TICE increases the sublimation of ice particles, consequently playing a partial role in reducing the amount of surface precipitation. The effects of TICE are less pronounced in the sheared basic-state wind cases than in the uniform basic-state wind cases because the number of ice crystals is much smaller in the sheared basic-state wind cases than in the uniform basic-state wind cases. Thus, the size distributions of graupel particles in the cases with and without TICE show little difference.

  11. Comparison of GOES and MODIS aerosol optical depth (AOD) to aerosol robotic network (AERONET) AOD and IMPROVE PM2.5 mass at Bondville, Illinois.

    PubMed

    Green, Mark; Kondragunta, Shobha; Ciren, Pubu; Xu, Chuanyu

    2009-09-01

    Collocated Interagency Monitoring of Protected Visual Environments (IMPROVE) particulate matter (PM) less than 2.5 microm in aerodynamic diameter (PM2.5) chemically speciated data, mass of PM less than 10 microm in aerodynamic diameter (PM10), and Aerosol Robotic Network (AERONET) aerosol optical depth (AOD) and size distribution at Bondville, IL, were compared with satellite-derived AOD. This was done to evaluate the quality of the Geostationary Operational Environmental Satellite (GOES) and Moderate Resolution Imaging Spectroradiometer (MODIS) AOD data and their potential to predict surface PM2.5 concentrations. MODIS AOD correlated better to AERONET AOD (r = 0.835) than did GOES AOD (r = 0.523). MODIS and GOES AOD compared better to AERONET AOD when the particle size distribution was dominated by fine mode. For all three AOD methods, correlation between AOD and PM2.5 concentration was highest in autumn and lowest in winter. The AERONET AOD-PM2.5 relationship was strongest with moderate relative humidity (RH). At low RH, AOD attributable to coarse mass degrades the relationship; at high RH, added AOD from water growth appears to mask the relationship. For locations such as many in the central and western United States with substantial coarse mass, coarse mass contributions to AOD may make predictions of PM2.5 from AOD data problematic. Seasonal and diurnal variations in particle size distributions, RH, and seasonal changes in boundary layer height need to be accounted for to use satellite AOD to predict surface PM2.5.

  12. Black Carbon Concentration from Worldwide Aerosol Robotic Network (AERONET) Measurements

    NASA Technical Reports Server (NTRS)

    Schuster, Gregory L.; Dubovik, Oleg; Holben, Brent N.; Clothiaux, Eugene E.

    2006-01-01

    The carbon emissions inventories used to initialize transport models and general circulation models are highly parameterized, and created on the basis of multiple sparse datasets (such as fuel use inventories and emission factors). The resulting inventories are uncertain by at least a factor of 2, and this uncertainty is carried forward to the model output. [Bond et al., 1998, Bond et al., 2004, Cooke et al., 1999, Streets et al., 2001] Worldwide black carbon concentration measurements are needed to assess the efficacy of the carbon emissions inventory and transport model output on a continuous basis.

  13. Analysis of secondary organic aerosols from ozonolysis of isoprene by proton transfer reaction mass spectrometry

    NASA Astrophysics Data System (ADS)

    Inomata, Satoshi; Sato, Kei; Hirokawa, Jun; Sakamoto, Yosuke; Tanimoto, Hiroshi; Okumura, Motonori; Tohno, Susumu; Imamura, Takashi

    2014-11-01

    To understand the mechanism of formation of the secondary organic aerosols (SOAs) produced by the ozonolysis of isoprene, proton transfer reaction mass spectrometry (PTR-MS) was used to identify the semi-volatile organic compounds (SVOCs) produced in both the gaseous and the aerosol phases and to estimate the gas-aerosol partitioning of each SVOC in chamber experiments. To aid in the identification of the SVOCs, the products were also studied with negative ion-chemical ionization mass spectrometry (NI-CIMS), which can selectively detect carboxylic acids and hydroperoxides. The gaseous products were observed by on-line PTR-MS and NI-CIMS, whereas the SVOCs in SOAs collected on a filter were vaporized by heating the filter and were then analysed by off-line PTR-MS and NI-CIMS. The formation of oligomeric hydroperoxides involving a Criegee intermediate as a chain unit was observed in both the gaseous and the aerosol phases by NI-CIMS. PTR-MS also detected oligomeric hydroperoxides as protonated molecules from which a H2O molecule was eliminated, [M-OH]+. In the aerosol phase, oligomers involving formaldehyde and methacrolein as chain units were observed by PTR-MS in addition to oligomeric hydroperoxides. The gas-aerosol partitioning of each component was calculated from the ion signals in the gaseous and aerosol phases measured by PTR-MS. From the gas-aerosol partitioning, the saturated vapour pressures of the oligomeric hydroperoxides were estimated. Measurements by a fast-mobility-particle-sizer spectrometer revealed that the increase of the number density of the particles was complete within a few hundred seconds from the start of the reaction.

  14. Characterization of Organic Nitrogen in the Atmosphere Using High Resolution Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ge, X.; Sun, Y.; Chen, M.; Zhang, Q.

    2015-12-01

    Despite extensive efforts on characterizing organic nitrogen (ON) compounds in atmospheric aerosols and aqueous droplets, knowledge of ON chemistry is still limited, mainly due to its chemical complexity and lack of highly time-resolved measurements. This work is aimed at optimizing the method of using Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) to characterize ON compounds in atmospheric aerosols. Seventy-five pure nitrogen-containing organic compounds covering a variety of functional groups were analyzed with the HR-AMS. Our results show that ON compounds commonly produce NHx+, NOx+, which are usually attributed to inorganic N species such as ammonium and nitrate, and CH2N+ at m/z = 28, which is rarely quantified in ambient aerosol due to large interference from N2+ in the air signal. As a result, using the nitrogen-to-carbon (N/C) calibration factor proposed by Aiken et al. (2008) on average leads to ~ 20% underestimation of N/C in ambient organic aerosol. A new calibration factor of 0.79 is proposed for determining the average N/C in organics. The relative ionization efficiencies (RIEs) of different ON species, on average, are found to be consistent with the default RIE value (1.4) for the total organics. The AMS mass spectral features of various types of ON species (amines, amides, amino acids, etc.) are examined and used for characterizing ON composition in ambient aerosols. Our results indicate that submicron organic aerosol measured during wintertime in Fresno, CA contains significant amounts of amino-compounds whereas more diversified ON species, including N-containing aromatic heterocycle (e.g., imidazoles), are observed in fog waters collected simultaneously. Our findings have important implications for understanding atmospheric ON behaviors via the widespread HR-AMS measurements of ambient aerosols and droplets.

  15. Vertical distribution of aerosol number concentration in the troposphere over Siberia derived from airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Arshinov, Mikhail Yu.; Belan, Boris D.; Paris, Jean-Daniel; Machida, Toshinobu; Kozlov, Alexandr; Malyskin, Sergei; Simonenkov, Denis; Davydov, Denis; Fofonov, Alexandr

    2016-04-01

    Knowledge of the vertical distribution of aerosols particles is very important when estimating aerosol radiative effects. To date there are a lot of research programs aimed to study aerosol vertical distribution, but only a few ones exist in such insufficiently explored region as Siberia. Monthly research flights and several extensive airborne campaigns carried out in recent years in Siberian troposphere allowed the vertical distribution of aerosol number concentration to be summarized. In-situ aerosol measurements were performed in a wide range of particle sizes by means of improved version of the Novosibirsk-type diffusional particle sizer and GRIMM aerosol spectrometer Model 1.109. The data on aerosol vertical distribution enabled input parameters for the empirical equation of Jaenicke (1993) to be derived for Siberian troposphere up to 7 km. Vertical distributions of aerosol number concentration in different size ranges averaged for the main seasons of the year will be presented. This work was supported by Interdisciplinary integration projects of the Siberian Branch of the Russian Academy of Science No. 35, No. 70 and No. 131; the Branch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5); and Russian Foundation for Basic Research (grant No. 14-05-00526). Jaenicke R. Tropospheric aerosols, in Aerosol-Cloud-Climate Interactions, edited by P.V. Hobs. -Academic Press, San Diego, CA, 1993.- P. 1-31.

  16. Simulations of organic aerosol concentrations during springtime in the Guanzhong Basin, China

    NASA Astrophysics Data System (ADS)

    Feng, Tian; Li, Guohui; Cao, Junji; Bei, Naifang; Shen, Zhenxing; Zhou, Weijian; Liu, Suixin; Zhang, Ting; Wang, Yichen; Huang, Ru-jin; Tie, Xuexi; Molina, Luisa T.

    2016-08-01

    The organic aerosol (OA) concentration is simulated in the Guanzhong Basin, China from 23 to 25 April 2013 utilizing the WRF-CHEM model. Two approaches are used to predict OA concentrations: (1) a traditional secondary organic aerosol (SOA) module; (2) a non-traditional SOA module including the volatility basis-set modeling method in which primary organic aerosol (POA) is assumed to be semivolatile and photochemically reactive. Generally, the spatial patterns and temporal variations of the calculated hourly near-surface ozone and fine particle matters agree well with the observations in Xi'an and surrounding areas. The model also yields reasonable distributions of daily PM2.5 and elemental carbon (EC) compared to the filter measurements at 29 sites in the basin. Filter-measured organic carbon (OC) and EC are used to evaluate OA, POA, and SOA using the OC / EC ratio approach. Compared with the traditional SOA module, the non-traditional module significantly improves SOA simulations and explains about 88 % of the observed SOA concentration. Oxidation and partitioning of POA treated as semivolatile constitute the most important pathway for the SOA formation, contributing more than 75 % of the SOA concentrations in the basin. Residential emissions are the dominant anthropogenic OA source, constituting about 50 % of OA concentrations in urban and rural areas and 30 % in the background area. The OA contribution from transportation emissions decreases from 25 % in urban areas to 20 % in the background area, and the industry emission OA contribution is less than 6 %.

  17. Trace metal concentration in Trade Wind aerosols collected over Barbados and Miami.

    NASA Astrophysics Data System (ADS)

    Trapp, J. M.; Millero, F. J.; Prospero, J. M.

    2007-12-01

    African mineral dust aerosols are transported by trade winds to Barbados and often reach Miami. The trace metals contained in these aerosols play an important role in biogeochemical processes and thus the global carbon cycle. High-volume bulk aerosols were collected in the summer dust season (June-September) of 2003 and 2004 in Miami and Barbados on Whatman-41 filters and microwave digested using a modified version of EPA method 3051. Aliquots of digested samples were tested for trace metal concentrations by ICP-MS. Excellent agreement with gravimetrically determined ashed weights was observed with dust concentrations calculated based on Al crustal abundance. As a major component, aluminum averaged 8.7% content in agreement to 8.1% crustal abundance, and was used to examine other trace metals. Al, Fe, V, Cr, Mn, Cu, Co, Ni, Zn, As, Tl, Ba, Cd, Pb and REE's were examined and deviations from average crustal abundance are discussed in relationship to temporal variation and meteorological conditions. In addition, trace metal pollutants in Miami aerosols were examined relative to the relatively clean samples offered by Barbados.

  18. Mapping of PM10 surface concentrations derived from satellite observations of aerosol optical thickness over South-Eastern France

    NASA Astrophysics Data System (ADS)

    Péré, J.-C.; Pont, V.; Mallet, M.; Bessagnet, B.

    2009-01-01

    This work aims at developing a methodology based on in-situ experimental observations in order to use satellite retrievals as a tool for monitoring air particulate pollution. This methodology is applied during summer time on the South-Eastern France, which is one of the most polluted zones over Europe, enclosing further large cities and industrial sites. In a first time, we consider correlations between daily mean AERONET AOT and PM10 concentrations at five sites located as well close to as far from pollution sources. Our results show significant correlation coefficients, ranging from 0.68 to 0.79, following the site studied. Several factors like aerosol vertical distribution or hygroscopic growth factor could affect the link between PM10 ground measurements and aerosol optical thickness. To statistically strengthen this approach, we gather data sets from three types of sites (urban, near urban and rural) and establish a linear relationship between daily mean AOT measured from AERONET and PM10 mass concentrations. Secondly and thanks to good agreements between AOT measured from AERONET and AOT retrieved from the MODIS sensor, we calculate estimated concentrations of PM10 by using MODIS retrievals above the South-Eastern France. Uncertainties about this approach are discussed.

  19. Reduction in biomass burning aerosol light absorption upon humidification: Roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

    SciTech Connect

    lewis, Kristen A.; Arnott, W. P.; Moosmuller, H.; Chakrabarti, Raj; Carrico, Christian M.; Kreidenweis, Sonia M.; Day, Derek E.; Malm, William C.; Laskin, Alexander; Jimenez, Jose L.; Ulbrich, Ingrid M.; Huffman, John A.; Onasch, Timothy B.; Trimborn, Achim; Liu, Li; Mishchenko, M.

    2009-11-27

    Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used are Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients reveal a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: 1. Shielding of inner monomers after particle consolidation or collapse with water uptake; 2. The contribution of mass transfer through evaporation and condensation at high relative humidity to the usual heat transfer pathway for energy release by laser heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

  20. Effect of oxidant concentration, exposure time, and seed particles on secondary organic aerosol chemical composition and yield

    DOE PAGES

    Lambe, A. T.; Chhabra, P. S.; Onasch, T. B.; ...

    2015-03-18

    We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH concentrations ranging from 2.0 × 108 to 2.2 × 1010 molec cm-3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH concentrations ranging from 2 × 106 to 2 × 107 molec cm-3 over exposure times of several hours. The OH concentration in themore » chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approximately 1 × 1011 and 2 × 1011 molec cm-3 s, or about 1–2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental composition as measured by an aerosol mass spectrometer is similar whether the precursor is exposed to low OH concentrations over long exposure times or high OH concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of

  1. Aerosol-Radiation Feedback and PM10 Air Concentrations Over Poland

    NASA Astrophysics Data System (ADS)

    Werner, Małgorzata; Kryza, Maciej; Skjøth, Carsten Ambelas; Wałaszek, Kinga; Dore, Anthony J.; Ojrzyńska, Hanna; Kapłon, Jan

    2017-02-01

    We have implemented the WRF-Chem model version 3.5 over Poland to quantify the direct and indirect feedback effects of aerosols on simulated meteorology and aerosol concentrations. Observations were compared with results from three simulations at high spatial resolutions of 5 × 5 km: (1) BASE—without any aerosol feedback effects; (2) DIR—with direct aerosol-radiative effects (3) INDIR—with direct and indirect aerosol-radiative effects. We study the overall effect during January 2011 as well as selected episodes of the highest differences in PM10 concentrations between the three simulations. For the DIR simulation, the decrease in monthly mean incoming solar radiation (SWDOWN) appears for the entire study area. It changes geographically, from about -8.0 to -2.0 W m-2, respectively for the southern and northern parts of the country. The highest changes do not correspond to the highest PM10 concentration. Due to the solar radiation changes, the surface mean monthly temperature (T2) decreases for 96 % of the area of Poland, but not more than 1.0 °C. Monthly mean PBLH changes by more than ±5 m for 53 % of the domain. Locally the differences in PBLH between the DIR and BASE are higher than ± 20 m. Due to the direct effect, for 84 % of the domain, the mean monthly PM10 concentrations increase by up to 1.9 µg m-3. For the INDIR simulation the spatial distribution of changes in incoming solar radiation as well as air temperature is similar to the DIR simulation. The decrease of SWDOWN is noticed for the entire domain and for 23 % of the domain is higher than -5.0 W m-2. The absolute differences of PBLH are slightly higher for INDIR than DIR but similarly distributed spatially. For daily episodes, the differences between the simulations are higher, both for meteorology and PM10 concentrations, and the pattern of changes is usually more complex. The results indicate the potential importance of the aerosol feedback effects on modelled meteorology and PM10

  2. Simulations of organic aerosol concentrations in Mexico City using the WRF-CHEM model during the MCMA-2006/MILAGRO campaign

    NASA Astrophysics Data System (ADS)

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

    2011-04-01

    Organic aerosol concentrations are simulated using the WRF-CHEM model in Mexico City during the period from 24 to 29 March in association with the MILAGRO-2006 campaign. Two approaches are employed to predict the variation and spatial distribution of the organic aerosol concentrations: (1) a traditional 2-product secondary organic aerosol (SOA) model with non-volatile primary organic aerosols (POA); (2) a non-traditional SOA model including the volatility basis-set modeling method in which primary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA (Mexico City Metropolitan Area) 2006 official emission inventory is used in simulations and the POA emissions are modified and distributed by volatility based on dilution experiments for the non-traditional SOA model. The model results are compared to the Aerosol Mass Spectrometry (AMS) observations analyzed using the Positive Matrix Factorization (PMF) technique at an urban background site (T0) and a suburban background site (T1) in Mexico City. The traditional SOA model frequently underestimates the observed POA concentrations during rush hours and overestimates the observations in the rest of the time in the city. The model also substantially underestimates the observed SOA concentrations, particularly during daytime, and only produces 21% and 25% of the observed SOA mass in the suburban and urban area, respectively. The non-traditional SOA model performs well in simulating the POA variation, but still overestimates during daytime in the urban area. The SOA simulations are significantly improved in the non-traditional SOA model compared to the traditional SOA model and the SOA production is increased by more than 100% in the city. However, the underestimation during daytime is still salient in the urban area and the non-traditional model also fails to reproduce the high level of SOA concentrations in the suburban area

  3. Simulations of organic aerosol concentrations in Mexico City using the WRF-CHEM model during the MCMA-2006/MILAGRO campaign

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    Organic aerosol concentrations are simulated using the WRF-CHEM model in Mexico City during the period from 24 to 29 March in association with the MILAGRO-2006 campaign. Two approaches are employed to predict the variation and spatial distribution of the organic aerosol concentrations: (1) a traditional 2-product secondary organic aerosol (SOA) model with non-volatile primary organic aerosols (POA); (2) a non-traditional SOA model including the volatility basis-set modeling method in which primary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA 2006 official emission inventory is used in simulations and the POA emissions are modified and distributed by volatility based on dilution experiments for the non-traditional SOA model. The model results are compared to the Aerosol Mass Spectrometry (AMS) observations analyzed using the Positive Matrix Factorization (PMF) technique at an urban background site (T0) and a suburban background site (T1) in Mexico City. The traditional SOA model frequently underestimates the observed POA concentrations during rush hours and overestimates the observations in the rest of the time in the city. The model also substantially underestimates the observed SOA concentrations, particularly during daytime, and only produces 21% and 25% of the observed SOA mass in the suburban and urban area, respectively. The non-traditional SOA model performs well in simulating the POA variation, but still overestimates during daytime in the urban area. The SOA simulations are significantly improved in the non-traditional SOA model compared to the traditional SOA model and the SOA production is increased by more than 100% in the city. However, the underestimation during daytime is still salient in the urban area and the non-traditional model also fails to reproduce the high level of SOA concentrations in the suburban area. In the non-traditional SOA model

  4. Aerosol mass spectrometry: particle-vaporizer interactions and their consequences for the measurements

    NASA Astrophysics Data System (ADS)

    Drewnick, F.; Diesch, J.-M.; Faber, P.; Borrmann, S.

    2015-09-01

    The Aerodyne aerosol mass spectrometer (AMS) is a frequently used instrument for on-line measurement of the ambient sub-micron aerosol composition. With the help of calibrations and a number of assumptions on the flash vaporization and electron impact ionization processes, this instrument provides robust quantitative information on various non-refractory ambient aerosol components. However, when measuring close to certain anthropogenic or marine sources of semi-refractory aerosols, several of these assumptions may not be met and measurement results might easily be incorrectly interpreted if not carefully analyzed for unique ions, isotope patterns, and potential slow vaporization associated with semi-refractory species. Here we discuss various aspects of the interaction of aerosol particles with the AMS tungsten vaporizer and the consequences for the measurement results: semi-refractory components - i.e., components that vaporize but do not flash-vaporize at the vaporizer and ionizer temperatures, like metal halides (e.g., chlorides, bromides or iodides of Al, Ba, Cd, Cu, Fe, Hg, K, Na, Pb, Sr, Zn) - can be measured semi-quantitatively despite their relatively slow vaporization from the vaporizer. Even though non-refractory components (e.g., NH4NO3 or (NH4)2SO4) vaporize quickly, under certain conditions their differences in vaporization kinetics can result in undesired biases in ion collection efficiency in thresholded measurements. Chemical reactions with oxygen from the aerosol flow can have an influence on the mass spectra for certain components (e.g., organic species). Finally, chemical reactions of the aerosol with the vaporizer surface can result in additional signals in the mass spectra (e.g., WO2Cl2-related signals from particulate Cl) and in conditioning or contamination of the vaporizer, with potential memory effects influencing the mass spectra of subsequent measurements. Laboratory experiments that investigate these particle-vaporizer interactions are

  5. Mass Spectrometry of Liquid Aniline Aerosol Particles by IR/UV Laser Irradiation.

    PubMed

    Zelenyuk, A; Cabalo, J; Baer, T; Miller, R E

    1999-05-01

    The first results are reported from a new single-particle two-color laser time-of-flight mass spectrometer, incorporating a combination of infrared (CO(2)) and UV (excimer) laser irradiation. This combination of lasers has the capability to effectively separate the desorption or evaporation step from the ionization step, thereby greatly improving the analytical capabilities of such an instrument. The results on liquid aerosols, such as aniline, show that prior evaporation of the aerosol particle with the IR laser increases the ion signal produced by the excimer laser by more than 2 orders of magnitude. In the case of nitrobenzene aerosols, the excimer laser alone produces no ions, while a very large signal is observed when the aerosol is first irradiated with the CO(2) laser. A simple model, based on the Coulomb explosion of the ionized aerosol, is used to estimate the number of ions generated by the excimer laser (∼10(5) ions). Experimental evidence based on the observed time delay of protonated aniline parent ions indicates that the laser irradiation of the liquid aerosol results in a stable neutral plasma which separates into positive and negative charges only after a 100-500-ns delay.

  6. Characterization of a real-time tracer for isoprene epoxydiols-derived secondary organic aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

    NASA Astrophysics Data System (ADS)

    Hu, W. W.; Campuzano-Jost, P.; Palm, B. B.; Day, D. A.; Ortega, A. M.; Hayes, P. L.; Krechmer, J. E.; Chen, Q.; Kuwata, M.; Liu, Y. J.; de Sá, S. S.; McKinney, K.; Martin, S. T.; Hu, M.; Budisulistiorini, S. H.; Riva, M.; Surratt, J. D.; St. Clair, J. M.; Isaacman-Van Wertz, G.; Yee, L. D.; Goldstein, A. H.; Carbone, S.; Brito, J.; Artaxo, P.; de Gouw, J. A.; Koss, A.; Wisthaler, A.; Mikoviny, T.; Karl, T.; Kaser, L.; Jud, W.; Hansel, A.; Docherty, K. S.; Alexander, M. L.; Robinson, N. H.; Coe, H.; Allan, J. D.; Canagaratna, M. R.; Paulot, F.; Jimenez, J. L.

    2015-10-01

    Substantial amounts of secondary organic aerosol (SOA) can be formed from isoprene epoxydiols (IEPOX), which are oxidation products of isoprene mainly under low-NO conditions. Total IEPOX-SOA, which may include SOA formed from other parallel isoprene oxidation pathways, was quantified by applying positive matrix factorization (PMF) to aerosol mass spectrometer (AMS) measurements. The IEPOX-SOA fractions of organic aerosol (OA) in multiple field studies across several continents are summarized here and show consistent patterns with the concentration of gas-phase IEPOX simulated by the GEOS-Chem chemical transport model. During the Southern Oxidant and Aerosol Study (SOAS), 78 % of PMF-resolved IEPOX-SOA is accounted by the measured IEPOX-SOA molecular tracers (2-methyltetrols, C5-Triols, and IEPOX-derived organosulfate and its dimers), making it the highest level of molecular identification of an ambient SOA component to our knowledge. An enhanced signal at C5H6O+ (m/z 82) is found in PMF-resolved IEPOX-SOA spectra. To investigate the suitability of this ion as a tracer for IEPOX-SOA, we examine fC5H6O (fC5H6O= C5H6O+/OA) across multiple field, chamber, and source data sets. A background of ~ 1.7 ± 0.1 ‰ (‰ = parts per thousand) is observed in studies strongly influenced by urban, biomass-burning, and other anthropogenic primary organic aerosol (POA). Higher background values of 3.1 ± 0.6 ‰ are found in studies strongly influenced by monoterpene emissions. The average laboratory monoterpene SOA value (5.5 ± 2.0 ‰) is 4 times lower than the average for IEPOX-SOA (22 ± 7 ‰), which leaves some room to separate both contributions to OA. Locations strongly influenced by isoprene emissions under low-NO levels had higher fC5H6O (~ 6.5 ± 2.2 ‰ on average) than other sites, consistent with the expected IEPOX-SOA formation in those studies. fC5H6O in IEPOX-SOA is always elevated (12-40 ‰) but varies substantially between locations, which is shown to reflect

  7. Characterization of a real-time tracer for isoprene epoxydiols-derived secondary organic aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

    DOE PAGES

    Hu, W. W.; Campuzano-Jost, P.; Palm, B. B.; ...

    2015-10-23

    Substantial amounts of secondary organic aerosol (SOA) can be formed from isoprene epoxydiols (IEPOX), which are oxidation products of isoprene mainly under low-NO conditions. Total IEPOX-SOA, which may include SOA formed from other parallel isoprene oxidation pathways, was quantified by applying positive matrix factorization (PMF) to aerosol mass spectrometer (AMS) measurements. The IEPOX-SOA fractions of organic aerosol (OA) in multiple field studies across several continents are summarized here and show consistent patterns with the concentration of gas-phase IEPOX simulated by the GEOS-Chem chemical transport model. During the Southern Oxidant and Aerosol Study (SOAS), 78 % of PMF-resolved IEPOX-SOA is accountedmore » by the measured IEPOX-SOA molecular tracers (2-methyltetrols, C5-Triols, and IEPOX-derived organosulfate and its dimers), making it the highest level of molecular identification of an ambient SOA component to our knowledge. An enhanced signal at C5H6O+ (m/z 82) is found in PMF-resolved IEPOX-SOA spectra. To investigate the suitability of this ion as a tracer for IEPOX-SOA, we examine fC5H6O (fC5H6O= C5H6O+/OA) across multiple field, chamber, and source data sets. A background of ~ 1.7 ± 0.1 ‰ (‰ = parts per thousand) is observed in studies strongly influenced by urban, biomass-burning, and other anthropogenic primary organic aerosol (POA). Higher background values of 3.1 ± 0.6 ‰ are found in studies strongly influenced by monoterpene emissions. The average laboratory monoterpene SOA value (5.5 ± 2.0 ‰) is 4 times lower than the average for IEPOX-SOA (22 ± 7 ‰), which leaves some room to separate both contributions to OA. Locations strongly influenced by isoprene emissions under low-NO levels had higher fC5H6O (~ 6.5 ± 2.2 ‰ on average) than other sites, consistent with the expected IEPOX-SOA formation in those studies. fC5H6O in IEPOX-SOA is always elevated (12–40 ‰) but varies substantially between locations, which is shown

  8. Online Aerosol Mass Spectrometry of Single Micrometer-Sized Particles Containing Poly(ethylene glycol)

    SciTech Connect

    Bogan, M J; Patton, E; Srivastava, A; Martin, S; Fergenson, D; Steele, P; Tobias, H; Gard, E; Frank, M

    2006-10-25

    Analysis of poly(ethylene glycol)(PEG)-containing particles by online single particle aerosol mass spectrometers equipped with laser desorption ionization (LDI) is reported. We demonstrate that PEG-containing particles are useful in the development of aerosol mass spectrometers because of their ease of preparation, low cost, and inherently recognizable mass spectra. Solutions containing millimolar quantities of PEGs were nebulized and, after drying, the resultant micrometer-sized PEG containing particles were sampled. LDI (266 nm) of particles containing NaCl and PEG molecules of average molecular weight <500 generated mass spectra reminiscent of mass spectra of PEG collected by other MS schemes including the characteristic distribution of positive ions (Na{sup +} adducts) separated by the 44 Da of the ethylene oxide units separating each degree of polymerization. PEGs of average molecular weight >500 were detected from particles that also contained t the tripeptide tyrosine-tyrosine-tyrosine or 2,5-dihydroxybenzoic acid, which were added to nebulized solutions to act as matrices to assist LDI using pulsed 266 nm and 355 nm lasers, respectively. Experiments were performed on two aerosol mass spectrometers, one reflectron and one linear, that each utilize two time-of-flight mass analyzers to detect positive and negative ions created from a single particle. PEG-containing particles are currently being employed in the optimization of our bioaerosol mass spectrometers for the application of measurements of complex biological samples, including human effluents, and we recommend that the same strategies will be of great utility to the development of any online aerosol LDI mass spectrometer platform.

  9. Evidence for anthropogenic impact on number concentration and sulfate content of cloud-processed aerosol particles over the North-Atlantic

    NASA Astrophysics Data System (ADS)

    van Dingenen, Rita; Raes, Frank; Jensen, Niels R.

    1995-10-01

    Aerosol properties were measured during two transects over the North Atlantic between Halifax (Nova Scotia, Canada) and the Moroccan coast. Measurements of the chemical composition of total aerosol, of the black carbon concentration and of the number size distributions with particle diameter Dp in the range 16 nm < Dp < 1 μm were made. The e-folding lifetime of the black carbon aerosol, coming from the northeast American continent and transported eastward over the ocean, was estimated to be 15 hours. The non-sea-salt (nss) fraction of the sulfate concentrations encountered during this campaign spans a 3 order of magnitude range (0.02 μm m-3 to 19 μm m-3) and shows a high correlation with black carbon. The measured bimodal aerosol size distributions were analysed in order to yield number concentrations of the nuclei and the accumulation mode (ACM), the latter being interpreted as cloud-processed particles and thus as cloud condensation nuclei (CCN). A strong positive correlation was found between ACM number concentration and nss-sulfate load over the whole concentration range, i.e. for clean to polluted air masses. Furthermore, our regression between nss-sulfate and ACM number concentration also agrees well with results from other investigators where CCN or cloud droplet concentrations were related to nss-sulfate at a variety of geographical locations and degrees of pollution. The composite data set shows that the nss-sulfate-CCN relationship from baseline conditions to anthropogenically conditioned aerosol, happens via a smooth transition which can be described by a linear regression on a logarithmic scale.

  10. [Characteristics of carbonaceous aerosol concentration in snow and ice of glaciers in Tianshan Mountains].

    PubMed

    Wang, Sheng-Jie; Zhang, Ming-Jun; Wang, Fei-Teng; Li, Zhong-Qin

    2012-03-01

    The snow and ice samples, collected at Glacier No. 1 at the headwaters of Urumqi River (UG1) and Glacier No. 51 at Haxilegen of Kuytun River (HG51) in 2002 and 2004, were analyzed for organic carbon (OC) and element carbon (EC) by thermal/ optical reflectance (TOR). The spatio-temporal characteristics and environmental significance of OC and EC concentration were discussed in details. The concentration order of total carbon (TC) was: snowpack of west branch on UG1 (1 943 ng x g(-1)) > snowpack of east branch on UG1 (989 ng x g(-1)) > snowpack of HG51 (150 ng x g(-1)) > glacier ice of east branch on UG1 (77 ng x g(-1)), and the concentration order of OC and EC lay similar as TC. The concentration of OC and EC in snowpack of Tianshan Mountains were 557 ng x g(-1) and 188 ng x g(-1), respectively. Concentration peak of carbonaceous aerosol usually appeared near the dust layer at the bottom section of snowpack, but the some sudden events could increase the concentration in the surface snow. Because of the seasonality of carbon emission (e. g. heating and agricultural activities) and transportation (e. g. atmospheric circulation), the concentration of carbonaceous aerosol increased from July to November with fluctuations. Difference on the order of magnitude might exist between the concentration in snow (firn) and glacier ice, which was influenced by the glacier surroundings, sampling situation and other factors. EC on the surface snow affected the albedo significantly, and an average albedo reduction of 0.22 in the wavelength of 300-700 nm was simulated by SNICAR (snow, ice, and aerosol radiative) model.

  11. Contribution of feldspar and marine organic aerosols to global ice nucleating particle concentrations

    NASA Astrophysics Data System (ADS)

    Vergara-Temprado, Jesús; Murray, Benjamin J.; Wilson, Theodore W.; O'Sullivan, Daniel; Browse, Jo; Pringle, Kirsty J.; Ardon-Dryer, Karin; Bertram, Allan K.; Burrows, Susannah M.; Ceburnis, Darius; DeMott, Paul J.; Mason, Ryan H.; O'Dowd, Colin D.; Rinaldi, Matteo; Carslaw, Ken S.

    2017-03-01

    Ice-nucleating particles (INPs) are known to affect the amount of ice in mixed-phase clouds, thereby influencing many of their properties. The atmospheric INP concentration changes by orders of magnitude from terrestrial to marine environments, which typically contain much lower concentrations. Many modelling studies use parameterizations for heterogeneous ice nucleation and cloud ice processes that do not account for this difference because they were developed based on INP measurements made predominantly in terrestrial environments without considering the aerosol composition. Errors in the assumed INP concentration will influence the simulated amount of ice in mixed-phase clouds, leading to errors in top-of-atmosphere radiative flux and ultimately the climate sensitivity of the model. Here we develop a global model of INP concentrations relevant for mixed-phase clouds based on laboratory and field measurements of ice nucleation by K-feldspar (an ice-active component of desert dust) and marine organic aerosols (from sea spray). The simulated global distribution of INP concentrations based on these two species agrees much better with currently available ambient measurements than when INP concentrations are assumed to depend only on temperature or particle size. Underestimation of INP concentrations in some terrestrial locations may be due to the neglect of INPs from other terrestrial sources. Our model indicates that, on a monthly average basis, desert dusts dominate the contribution to the INP population over much of the world, but marine organics become increasingly important over remote oceans and they dominate over the Southern Ocean. However, day-to-day variability is important. Because desert dust aerosol tends to be sporadic, marine organic aerosols dominate the INP population on many days per month over much of the mid- and high-latitude Northern Hemisphere. This study advances our understanding of which aerosol species need to be included in order to

  12. Determination of particulate lead during MILAGRO/MCMA-2006 using Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Salcedo, D.; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

    2010-02-01

    We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO)/Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600 °C. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ<0.1 s) and ~75% exhibiting slow evaporation (τ~2.4 min) at the T0 urban supersite and a different fraction (70% prompt and 30% slow evaporation) at a site northwest from the metropolitan area (PEMEX site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at T0 (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 min with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the compounds generating Pb

  13. Determination of particulate lead during MILAGRO / MCMA-2006 using Aerosol Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Salcedo, Dara; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

    2010-05-01

    We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO) / Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600oC. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ < 0.1 s) and ~75% exhibiting slow evaporation (τ ~2.4 min) at T0 and a different fraction (70% prompt and 30% slow evaporation) at a site northwest from the metropolitan area (PEMEX32 site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at the T0 urban supersite during MILAGRO (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 minutes with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the

  14. Determination of particulate lead using aerosol mass spectrometry: MILAGRO/MCMA-2006 observations

    NASA Astrophysics Data System (ADS)

    Salcedo, D.; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

    2010-06-01

    We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO)/Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600 °C. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ<0.1 s) and ~75% exhibiting slow evaporation (τ~2.4 min) at the T0 urban supersite and a different fraction (70% prompt and 30% slow evaporation) at a site northwest from the metropolitan area (PEMEX site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at the T0 supersite during MILAGRO (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 min with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the

  15. The Influence of High Aerosol Concentration on Atmospheric Boundary Layer Temperature Stratification

    SciTech Connect

    Khaykin, M.N.; Kadygrove, E.N.; Golitsyn, G.S.

    2005-03-18

    Investigations of the changing in the atmospheric boundary layer (ABL) radiation balance as cased by natural and anthropogenic reasons is an important topic of the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program. The influence of aerosol on temperature stratification of ABL while its concentration was extremely high within a long period of time was studied experimentally. The case was observed in Moscow region (Russia) with the transport of combustion products from peat-bog and forest fires in July-September, 2002. At this time the visibility was some times at about 100-300 m. Aerosol concentration measured by Moscow University Observatory and A.M. Obukhov Institute of Atmospheric Physics field station in Zvenigorod (55.7 N; 36.6 E) for several days was in 50-100 times more than background one (Gorchakov at al 2003). The high aerosol concentration can change the radiation balance at ABL, and so to change thermal stratification in ABL above the mega lopolis. For the analysis the data were used of synchronous measurements by MTP-5 (Microwave Temperature Profiler operating at wavelength 5 mm) in two locations, namely: downtown Moscow and country-side which is 50 km apart to the West (Zvenigorod station). (Kadygrov and Pick 1998; Westwater at al 1999; Kadygrov at al 2002). Zvenigorod station is located in strongly continental climate zone which is in between of the climates of ARM sites (NSANorth Slope of Alaska and SGP-Southern Great Plains). The town of Zvenigorod has little industry, small traffic volume and topography conductive to a good air ventilation of the town. For these reasons Zvenigorod can be considered as an undisturbed rural site. For the analysis some days were chosen with close meteorological parameters (average temperature, humidity, wind, pressure and cloud form) but strongly differing in aerosol concentration level.

  16. Influence of a high aerosol concentration on the thermal structure of the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Khaikin, M. N.; Kuznetsova, I. N.; Kadygrov, E. N.

    2006-12-01

    The influence of increased concentrations of submicron aerosol produced by forest fires on thermal characteristics of the atmospheric boundary layer (ABL) in Moscow and its remote vicinity (the town of Zvenigorod) are analyzed on the basis of regular remote measurements of the ABL temperature profile with the use of MTP-5 profilers. In the air basin of a large city, additional aerosol and accompanying pollutants in early morning hours (at small heights of the Sun) most frequently did not cause substantial changes in the ABL thermal structure. In the locality remote from the megalopolis (Zvenigorod), the atmospheric pollution by aerosol led to noticeable changes in the ABL thermal characteristics. Especially strong changes were observed in the daytime, during the maximum supply of solar radiation. In morning hours, the heating rate of the lower 100-m layer of the polluted air exceeded the heating rate of a relatively pure air by more than one degree. In higher layers, the differences between the rates of temperature changes in a relatively clean atmosphere and in an atmosphere polluted by aerosol (in the suburb) were insignificant.

  17. Effect of high concentrations of inorganic seed aerosols on secondary organic aerosol formation in the m-xylene/NO x photooxidation system

    NASA Astrophysics Data System (ADS)

    Lu, Zifeng; Hao, Jiming; Takekawa, Hideto; Hu, Lanhua; Li, Junhua

    High concentrations (>15 μm 3 cm -3) of CaSO 4, Ca(NO 3) 2 and (NH 4) 2SO 4 were selected as surrogates of dry neutral, aqueous neutral and dry acidic inorganic seed aerosols, respectively, to study the effects of inorganic seeds on secondary organic aerosol (SOA) formation in irradiated m-xylene/NO x photooxidation systems. The results indicate that neither ozone formation nor SOA formation is significantly affected by the presence of neutral aerosols (both dry CaSO 4 and aqueous Ca(NO 3) 2), even at elevated concentrations. The presence of high concentrations of (NH 4) 2SO 4 aerosols (dry acidic) has no obvious effect on ozone formation, but it does enhance SOA generation and increase SOA yields. In addition, the effect of dry (NH 4) 2SO 4 on SOA yield is found to be positively correlated with the (NH 4) 2SO 4 surface concentration, and the effect is pronounced only when the surface concentration reaches a threshold value. Further, it is proposed that the SOA generation enhancement is achieved by particle-phase heterogeneous reactions induced and catalyzed by the acidity of dry (NH 4) 2SO 4 seed aerosols.

  18. Physical and chemical characterization of marine atmospheric aerosols over the North and South Pacific Oceans using single particle mass spectrometry

    NASA Astrophysics Data System (ADS)

    Furutani, H.; Jung, J.; Miura, K.; Uematsu, M.

    2010-12-01

    Physical and chemical properties of marine atmospheric aerosols were characterized and compared over the North and South Pacific Ocean during two trans-Pacific cruises (from Japan to Chile and Australia to Japan) during the period of January-June 2009, which cover broad region of Pacific Ocean from 40°N to 55°S and 140°E to 70°W. The measured parameters of aerosol properties were single particle size-resolved chemical composition (D = 100 ~ 1500 nm), cloud condensation nuclei (CCN) and condensation nuclei (CN) concentrations, size distribution from 10 nm to 5 μm, total aerosol nitrate and sulfate concentrations, and filter-based chemical composition. Trace gas concentrations of O3 and CO were also measured to aid air parcel categorization during the cruises. Reflecting larger anthropogenic emission in the Northern Hemisphere, pronounced concentration gradient between the North and South Pacific Ocean was observed for aerosol nitrate, CO, and O3. Aerosol sulfate also showed a similar concentration drop in the equatorial region, relatively higher sulfate concentration was observed in 30°S-40°S and 55°S regions, which was associated with increased aerosol methanesulfonic acid (MSA) concentration but little increase in local marine chlorophyll concentration, suggesting contribution of long-range transported marine biogenic sulfur from the high primary production area over the South Pacific high latitude region. Aerosol chemical classification by single particle chemical analysis revealed that certain aerosol types, such as biomass burning, elemental carbon, and elemental/organic carbon mixed type, were mainly observed in the North Pacific region, while several specific organic aerosol types with abundant aged organic and disulfur composition were identified in the South Pacific region. Further comparison of aerosol properties, aerosol sources, and atmospheric aerosol processing in the North and South Pacific Oceans will be discussed.

  19. Concentrations and composition of aerosols and particulate matter in surface waters along the transatlantic section

    NASA Astrophysics Data System (ADS)

    Nemirovskaya, I. A.; Lisitzin, A. P.; Novigatsky, A. N.; Redzhepova, Z. U.; Dara, O. M.

    2016-07-01

    Along the transatlantic section from Ushuaia to Gdańsk (March 26-May 7, 2015; cruise 47 of R/V Akademik Ioffe), data were obtained on the concentrations of aerosols in the near-water layer of the atmosphere and of particulate matter in surface waters, as well as of organic compounds within the considered matter (Corg, chlorophyll a, lipids, and hydrocarbons). The concentrations of aerosols amounted to 1237-111 739 particles/L for the fraction of 0.3-1 μm and to 0.02-34.4 μg/m2/day for the matter collected by means of the network procedure. The distribution of aerosols is affected by circumcontinental zoning and by the fluxes from arid areas of African deserts. The maximum concentration of the treated compounds were found in the river-sea frontal area (the runoff of the Colorado River, Argentina), as well as when nearing the coasts, especially in the English Channel.

  20. Aqueous aerosol SOA formation: impact on aerosol physical properties.

    PubMed

    Woo, Joseph L; Kim, Derek D; Schwier, Allison N; Li, Ruizhi; McNeill, V Faye

    2013-01-01

    Organic chemistry in aerosol water has recently been recognized as a potentially important source of secondary organic aerosol (SOA) material. This SOA material may be surface-active, therefore potentially affecting aerosol heterogeneous activity, ice nucleation, and CCN activity. Aqueous aerosol chemistry has also been shown to be a potential source of light-absorbing products ("brown carbon"). We present results on the formation of secondary organic aerosol material in aerosol water and the associated changes in aerosol physical properties from GAMMA (Gas-Aerosol Model for Mechanism Analysis), a photochemical box model with coupled gas and detailed aqueous aerosol chemistry. The detailed aerosol composition output from GAMMA was coupled with two recently developed modules for predicting a) aerosol surface tension and b) the UV-Vis absorption spectrum of the aerosol, based on our previous laboratory observations. The simulation results suggest that the formation of oligomers and organic acids in bulk aerosol water is unlikely to perturb aerosol surface tension significantly. Isoprene-derived organosulfates are formed in high concentrations in acidic aerosols under low-NO(x) conditions, but more experimental data are needed before the potential impact of these species on aerosol surface tension may be evaluated. Adsorption of surfactants from the gas phase may further suppress aerosol surface tension. Light absorption by aqueous aerosol SOA material is driven by dark glyoxal chemistry and is highest under high-NO(x) conditions, at high relative humidity, in the early morning hours. The wavelength dependence of the predicted absorption spectra is comparable to field observations and the predicted mass absorption efficiencies suggest that aqueous aerosol chemistry can be a significant source of aerosol brown carbon under urban conditions.

  1. OMI tropospheric NO2 air mass factors over South America: effects of biomass burning aerosols

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; Torres, O.; de Haan, J. F.

    2015-09-01

    Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2) to the atmosphere. Satellite observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospheric columns due to the radiative effects of aerosols, especially light-absorbing carbonaceous aerosols, are not well understood. It has been shown that the O2-O2 effective cloud fraction and pressure retrieval is sensitive to aerosol optical and physical properties, including aerosol optical depth (AOD). Aerosols implicitly influence the tropospheric air mass factor (AMF) calculations used in the NO2 retrieval through the effective cloud parameters used in the independent pixel approximation. In this work, we explicitly account for the effects of biomass burning aerosols in the Ozone Monitoring Instrument (OMI) tropospheric NO2 AMF calculation for cloud-free scenes. We do so by including collocated aerosol extinction vertical profile observations from the CALIOP instrument, and aerosol optical depth (AOD) and single scattering albedo (SSA) retrieved by the OMI near-UV aerosol algorithm (OMAERUV) in the DISAMAR radiative transfer model. Tropospheric AMFs calculated with DISAMAR were benchmarked against AMFs reported in the Dutch OMI NO2 (DOMINO) retrieval; the mean and standard deviation of the difference was 0.6 ± 8 %. Averaged over three successive South American biomass burning seasons (2006-2008), the spatial correlation in the 500 nm AOD retrieved by OMI and the 532 nm AOD retrieved by CALIOP was 0.6, and 68 % of the daily OMAERUV AOD observations were within 30 % of the CALIOP observations. Overall, tropospheric AMFs calculated with observed aerosol parameters were on average 10 % higher than AMFs calculated with effective cloud parameters. For effective cloud radiance fractions less than 30 %, or effective cloud pressures greater than 800 hPa, the difference between tropospheric AMFs based on implicit and

  2. Observations of Processed Asian Pollution with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) from the C-130 Aircraft During the INTEX-B Field Campaign

    NASA Astrophysics Data System (ADS)

    Dunlea, E.; Decarlo, P.; Aiken, A.; Kimmel, J.; Bahreini, R.; Peltier, R.; Weber, R.; Tomlinson, J.; Collins, D.; Shinozuka, Y.; Howell, S.; Clarke, A.; Emmons, L.; Apel, E.; Pfister, G.; van Donkelaar, A.; Millet, D.; Jimenez, J.

    2007-12-01

    Measurements of submicron, non-refractory aerosol mass were made from the NCAR/NSF C-130 aircraft using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) during the spring 2006 INTEX-B field campaign based in Seattle. We intercepted numerous Asian pollution layers, some after rapid transport across the Pacific and others after slower transport which had reduced aerosol concentrations and were depleted of short-lived tracers. The aerosol in Asian pollution layers intercepted over the Eastern Pacific Ocean was shown to have a predominance of sulfate over organic material, the latter being highly oxidized. Measurements and back trajectory calculations are consistent with the following sequence: (a) relatively more rapid conversion of organic precursors to organic aerosol compared to conversion of SO2 to sulfate just downwind of Asian urban centers and pollution sources, (b) uplift and transport of air masses resulting in washout of most aerosol material leaving relatively more SO2 available, and (c) subsequent SO2 to sulfate conversion as air masses are transported across the Pacific. This is consistent with Brock et al., JGR, 2004. Two case studies will be presented to describe this evolution of aerosol chemical composition during transport from Asia. Overall correlations of several tracers will be shown for comparing MOZART and GEOS-Chem model outputs with the measurements. Also, comparisons of AMS measurements with other aerosol instruments will be shown.

  3. A Minimal Fragmentation Approach to Real Time Aerosol Mass Spectrometry: A New Tool for Detailed Laboratory Studies of Organic Aerosol Aging

    NASA Astrophysics Data System (ADS)

    Campuzano-Jost, P.; Hanna, S.; Simpson, E.; Robb, D.; Blades, M. W.; Hepburn, J. W.; Bertram, A. K.

    2005-12-01

    The study of the atmospheric distribution and chemical processing of both biogenic and anthropogenic organics is one of the oldest and still most enduring challenges in atmospheric chemistry. The large number and structural complexity of many of the compounds as well as the high reactivity of many intermediates makes it hard to design analytical tools that are at the same time sensitive enough as well as being reasonably broad in scope. Despite big advances in techniques to characterize the gaseous phase component, there is still a dearth of instruments capable of doing the same for the organic aerosol component. This is due in part to the type of the compounds present in the aerosol phase, which in general lend themselves less to classical analytical methods such as GC/MS, as well as the inherent problems of any aerosol analysis, namely to transfer the aerosol to a suitable phase for analysis without altering it and while keeping track, at the same time, of the physical properties of the aerosol. Although impaction methods coupled to conventional analysis techniques have some specific advantages, the most widely used approach is the aerosol mass spectrometer. Unlike their predecessors, current aerosol mass spectrometer designs do a reasonably good job of delivering a representative sample of the aerosol phase to the detector while keeping track of the physical properties of the aerosol. However, the ionization step (either multitphoton absorption or electron impact in most cases) still leads to massive fragmentation of all but the most stable organics, making it very difficult to characterize individual compounds beyond establishing their functional groups(Allan et al. 2003; Su et al. 2004). Single photon near threshold ionization has been proposed and used recently (Oktem et al. 2004; Nash et al. 2005), but the challenges of producing coherent VUV radiation has led to a high detection threshold and a still significant amount of fragmentation, since these studies

  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. 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.

  6. Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site during SAPUSS - diurnal variations and PMF receptor modelling

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

    2013-04-01

    Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter < 2.5 μm) resolved aerosol samples analysed by Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie European Union framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the approach used is the simultaneous sampling at two monitoring sites in Barcelona (Spain) during September-October 2010: an urban background site (UB) and a street canyon traffic road site (RS). Elements related to primary non-exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (regional sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non-exhaust brake dust (Fe-Cu) - 7%), and three types of industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%, percentages presented are average source contributions to the total elemental mass measured). The validity of the PMF solution of the PIXE data is supported by very good correlations with external single particle mass spectrometry measurements. Some important conclusions can be drawn about the PM2.5 mass fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both

  7. Molecular composition of atmospheric aerosols from Halley Bay, Antarctica, using ultra-high resolution mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan; Brough, Neil; Rincon, Angela; Jones, Anna; Kalberer, Markus

    2016-04-01

    Antarctica is one of the few pristine places to study natural processes of atmospheric aerosols and anthropogenic impacts on the clean remote atmosphere. Although stratospheric aerosol in Antarctica has now been explored in some detail because of the ozone depletion phenomenon, tropospheric aerosol particles in Antarctica remain very little studied. The main goal of this work is to identify in detail the organic chemical composition of aerosol from Halley Bay station, which is located on the Brunt Ice Shelf floating on the Weddell Sea in Antarctica. In this study we characterise the molecular composition of aerosols from three seasons (summer, autumn and winter in 2012) using ultra-high resolution mass spectrometry (UHRMS). The technique provides high accuracy and high mass resolving power that allows determining unambiguous number of organic compounds present in complex organic mixtures (Noziere et al., 2015). The molecular composition interpretation was facilitated using visualisation methods (e.g. double bond equivalent, Van Krevelen diagrams, Kendrick mass analysis, and carbon oxidation state), which allowed to identify patterns, such as differences between sampling times and atmospheric processes. The majority of the identified compounds were attributed to nitrogen and sulphur containing species which exhibited very strong seasonal trends. Relatively large fraction (up to 30% of the total number of molecules) of these species contained very low hydrogen to carbon ratios (below 1) indicating that the site is impacted by anthropogenic emissions. Influences of the meteorological parameters and air mass trajectories on the molecular composition are discussed. Nozière et al., The Molecular Identification of Organic Compounds in the Atmosphere: State of the Art and Challenges, Chem. Rev., 115, 3920-3983, 2015.

  8. Atmospheric trace metals over the Atlantic and South Indian Oceans: Investigation of metal concentrations and lead isotope ratios in coastal and remote marine aerosols

    NASA Astrophysics Data System (ADS)

    Witt, Melanie; Baker, Alex R.; Jickells, Tim D.

    Atmospheric concentrations of trace metals over the oceans are investigated through analysis of aerosol samples collected during cruises from the UK to the Falkland Islands and from South Africa to Australia. The readily soluble concentrations of Cu (4-256 pmol m -3), Ni (0.1-54 pmol m -3), Ba (0.2-60 pmol m -3), Zn (6-316 pmol m -3), Cd (0.01-0.29 pmol m -3) and Pb (0.4-22 pmol m -3) were measured in the aerosols, along with total concentrations of crustal elements (Fe, Al and Mn) to evaluate the crustal contributions. Air mass back trajectories suggested most of the aerosol samples had spent several days over the ocean prior to collection. The highest metal concentrations were observed in aerosols close to South Africa, Australia and major cities in South America, although these concentrations were lower than had been reported previously in the literature. Apart from Ba, which had a major crustal source, the trace metals were enriched relative to crustal sources in most samples, including some collected thousands of kilometers from emission sources. The mean trace metal concentrations in the remote Indian Ocean were lower than those measured in the Atlantic Ocean. Even lower concentrations are reported in the literature for the remote Pacific Ocean. In contrast to previous studies, no clear north-south gradient is observed in the concentrations of the trace metals in the aerosols. Lead isotope measurements were also carried out on aerosol samples using a multicollector inductively coupled plasma mass spectrometer to assist in source apportionment. Clear differences were noted in the isotope ratios collected on either side of the Indian Ocean with Australian lead ore dominating over much of the eastern and mid-southern Indian Ocean. Samples collected over the western Indian Ocean and Atlantic Ocean under South African influence had lead isotopes quite different from those seen in South African cities in the past, and are closer in ratio to the coal signature of

  9. 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...

  10. SAGE and SAM II measurements of global stratospheric aerosol optical depth and mass loading

    NASA Technical Reports Server (NTRS)

    Kent, G. S.; Mccormick, M. P.

    1984-01-01

    Several volcanic eruptions between November 1979 and April 1981 have injected material into the stratosphere. The SAGE and SAM II satellite systems have measured, with global coverage, the 1-micron extinction produced by this material, and examples of the data product are shown in the form of global maps of stratospheric optical depth and altitude-latitude plots of zonal mean extinction. These data, and that for the volcanically quiet period in early 1979, have been used to determine the changes in the total stratospheric mass loading. Estimates have also been made of the contribution to the total aerosol mass from each eruption. It has been found that between 1979 and mid-1981, the total stratospheric aerosol mass increased from a background level of approximately 570,000 metric tons to a peak of approximately 1,300,000 metric tons.

  11. Local aerosol concentrations and optical characteristics influenced by the Indonesian forest fire

    NASA Astrophysics Data System (ADS)

    Ru, Jianfei; Minomura, Mitsuo; Kuze, Hiroaki; Takeuchi, Nobuo

    1998-08-01

    Indonesian forest fire took place on Kalimantan and Sumatera islands in 1997 and continuously influenced the atmospheric conditions of South-East Asia nearly throughout the last half of that year. The color composed images of visible, near IR and IR channels from NOAA AVHRR daily data, arbitrarily assigned to red, green and blue respectively, were synthesized for distinguishing the smoke area. The data of three periods, the beginning, mid, and ending parts of the fire, were collected and analyzed in order to show the variation of atmosphere with the development of fire. A retrieval algorithm was established by use of Mie theory calculation and the radiative transfer codes. Local aerosol concentrations and properties over ocean parts between the two islands were derived. It is found that the aerosol optical thickness increased in accordance with the exacerbation of the fires. The changes of angstrom exponents show that smaller particle amounts were raised by the effects of burning.

  12. Is It Possible to Distinguish Between Dust and Salt Aerosol Over Waters with Unknown Chlorophyll Concentrations Using Spectral Remote Sensing?

    NASA Technical Reports Server (NTRS)

    Levy, R. C.; Kaufman, Y. J.

    1999-01-01

    Atmospheric aerosol has uncertain impacts on the global climate system, as well as on atmospheric and bio-geo-chemical processes of regional and local scales. EOS-MODIS is one example of a satellite sensor designed to improve understanding of the aerosols' type, size and distribution at all temporal and spatial scales. Ocean scientists also plan to use data from EOS-MODIS to assess the temporal and spatial coverage of in-water chlorophyll. MODIS is the first sensor planned to observe the combined ocean-atmosphere system with a wide spectral range (from 410 to 2200 nm). Dust aerosol and salt aerosol have similar spectral signals for wavelengths longer than 550 nm, but because dust selectively absorbs blue light, they have divergent signals in the blue wavelength regions (412 to 490 nm). Chlorophyll also selectively absorbs blue radiation, so that varying chlorophyll concentrations produces a highly varying signal in the blue regions, but less variability in the green, and almost no signal in the red to mid-infrared regions. Thus, theoretically, it may be difficult to differentiate dust and salt in the presence of unknown chlorophyll in the ocean. This study attempts to address the cases in which aerosol and chlorophyll signals can and cannot be separated. For the aerosol spectra, we use the aerosol lookup table from the operational MODIS aerosol-over-ocean algorithm, and for chlorophyll spectra, we use the SeaBAM data set (created for SeaWiFS). We compare the signals using Principal Component Analysis and attempt to retrieve both chlorophyll and aerosol properties using a variant of the operational MODIS aerosol-over-ocean algorithm. Results show that for small optical depths, less than 0.5, it is not possible to differentiate between dust and salt and to determine the chlorophyll concentration at the same time. For larger aerosol optical depths, the chlorophyll signals are comparatively insignificant, and we can hope to distinguish between dust and salt.

  13. Relating Aerosol Profile and Column Measurements to Surface Concentrations: What Have We Learned from Discover-AQ?

    NASA Astrophysics Data System (ADS)

    Hoff, R. M.

    2014-12-01

    One research goal of the Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) mission was to determine sufficient column profile measurements to relate column integrated quantities such as Aerosol Optical Depth to surface concentrations. I will review the relationship between AOD and PM2.5 at the surface. DISCOVER-AQ in Baltimore, the San Joaquin Valley, Houston and Denver revealed quite different conditions for determining this relationship. In each case, the surface reflectivity made determination of aerosol optical depth challenging, but upward looking columns of aerosol optical depth from sunphotometers provided confirmation of the AOD results from space. In Baltimore, AOD fields reflected PM2.5 concentrations well. In California, however, the low boundary layer heights and dominance of nitrate and organic aerosols made the AOD fields less predictive of PM2.5. In California and Colorado, hydration of the aerosol varied dramatically with aerosol type (especially smoke and dust) and revealed that without an understanding of the degree of aerosol hydration with aerosol composition, the relationship between AOD and PM2.5 will continue to be a challenge. Model predictions in the Baltimore-Washington study are relatively disappointing in helping define the needed physics between the optical and microphysical properties. An overview of the measurements from DISCOVER-AQ which will help define the needed information in a more general case in the future will be given.

  14. Susceptibility of Tribolium confusum (Coleoptera: Tenebrionidae) to pyrethrin aerosol: effects of aerosol particle size, concentration, and exposure conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of laboratory studies were conducted to assess effect of droplet size on efficacy of pyrethrin aerosol against adults of Tribolium confusum Jacqueline DuVal, the confused flour beetle. A vertical flow aerosol exposure chamber that generated a standardized particle size diameter was used for...

  15. Aerosol mass spectrometry: particle-vaporizer interactions and their consequences for the measurements

    NASA Astrophysics Data System (ADS)

    Drewnick, F.; Diesch, J.-M.; Faber, P.; Borrmann, S.

    2015-04-01

    The Aerodyne Aerosol Mass Spectrometer (AMS) is a frequently used instrument for on-line measurement of the ambient sub-micron aerosol composition. With the help of calibrations and a number of assumptions on the flash vaporization and electron impact ionization processes this instrument provides robust quantitative information on various ambient aerosol components. However, when measuring close to certain anthropogenic sources or in marine environments, several of these assumptions may not be met and measurement results might easily be misinterpreted. Here we discuss various aspects of the interaction of aerosol particles with the AMS tungsten vaporizer and the consequences for the measurement results: semi-refractory components, i.e. components that vaporize but do not flash vaporize at the vaporizer and ionizer temperatures, like metal halides (e.g. chlorides, bromides or iodides of Al, Ba, Cd, Cu, Fe, Hg, K, Na, Pb, Sr, Zn) can be measured semi-quantitatively despite their relatively slow vaporization from the vaporizer. Even though non-refractory components (e.g. NH4NO3 or (NH4)2SO4) vaporize quickly, their differences in vaporization kinetics can result in undesired biases in ion collection efficiency in the measurements. Chemical reactions with water vapor and oxygen from the aerosol flow can have an influence on the mass spectra for certain components (e.g. NH4NO3, (NH4)2SO4, organic species). Finally, chemical reactions of the aerosol with the vaporizer surface can result in additional signals in the mass spectra (e.g. WO2C2-related signals from particulate Cl) and in conditioning or contamination of the vaporizer with potential memory effects influencing the mass spectra of subsequent measurements. Laboratory experiments that investigate these particle-vaporizer interactions are presented and are discussed together with field results showing that measurements of typical continental or urban aerosols are not significantly affected while laboratory

  16. A European aerosol phenomenology -4: Harmonized concentrations of carbonaceous aerosol at 10 regional background sites across Europe

    NASA Astrophysics Data System (ADS)

    Cavalli, F.; Alastuey, A.; Areskoug, H.; Ceburnis, D.; Čech, J.; Genberg, J.; Harrison, R. M.; Jaffrezo, J. L.; Kiss, G.; Laj, P.; Mihalopoulos, N.; Perez, N.; Quincey, P.; Schwarz, J.; Sellegri, K.; Spindler, G.; Swietlicki, E.; Theodosi, C.; Yttri, K. E.; Aas, W.; Putaud, J. P.

    2016-11-01

    Although particulate organic and elemental carbon (OC and EC) are important constituents of the suspended atmospheric particulate matter (PM), measurements of OC and EC are much less common and more uncertain than measurements of e.g. the ionic components of PM. In the framework of atmospheric research infrastructures supported by the European Union, actions have been undertaken to determine and mitigate sampling artefacts, and assess the comparability of OC and EC data obtained in a network of 10 atmospheric observatories across Europe. Positive sampling artefacts (from 0.4 to 2.8 μg C/m3) and analytical discrepancies (between -50% and +40% for the EC/TC ratio) have been taken into account to generate a robust data set, from which we established the phenomenology of carbonaceous aerosols at regional background sites in Europe. Across the network, TC and EC annual average concentrations range from 0.4 to 9 μg C/m3, and from 0.1 to 2 μg C/m3, respectively. TC/PM10 annual mean ratios range from 0.11 at a Mediterranean site to 0.34 at the most polluted continental site, and TC/PM2.5 ratios are slightly greater at all sites (0.15-0.42). EC/TC annual mean ratios range from 0.10 to 0.22, and do not depend much on PM concentration levels, especially in winter. Seasonal variations in PM and TC concentrations, and in TC/PM and EC/TC ratios, differ across the network, which can be explained by seasonal changes in PM source contributions at some sites.

  17. Potential Aerosol Mass (PAM) flow reactor measurements of SOA formation in a Ponderosa Pine forest in the southern Rocky Mountains during BEACHON-RoMBAS

    NASA Astrophysics Data System (ADS)

    Palm, B. B.; Ortega, A. M.; Campuzano Jost, P.; Day, D. A.; Kaser, L.; Karl, T.; Jud, W.; Hansel, A.; Fry, J.; Brown, S. S.; Zarzana, K. J.; Dube, W. P.; Wagner, N.; Draper, D.; Brune, W. H.; Jimenez, J. L.

    2012-12-01

    A Potential Aerosol Mass (PAM) photooxidation flow reactor was used in combination with an Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer to characterize biogenic secondary organic aerosol (SOA) formation in a terpene-dominated forest during the July-August 2011 Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study (BEACHON-RoMBAS) field campaign at the U.S. Forest Service Manitou Forest Observatory, Colorado, as well as in corresponding laboratory experiments. In the PAM reactor, a chosen oxidant (OH, O3, or NO3) was generated and controlled over a range of values up to 10,000 times ambient levels. High oxidant concentrations accelerated the gas-phase, heterogeneous, and possibly aqueous oxidative aging of volatile organic compounds (VOCs), inorganic gases, and existing aerosol, which led to repartitioning into the aerosol phase. PAM oxidative processing represented from a few hours up to ~20 days of equivalent atmospheric aging during the ~3 minute reactor residence time. During BEACHON-RoMBAS, PAM photooxidation enhanced SOA at intermediate OH exposure (1-10 equivalent days) but resulted in net loss of OA at long OH exposure (10-20 equivalent days), demonstrating the competing effects of functionalization vs. fragmentation (and possibly photolysis) as aging increased. PAM oxidation also resulted in f44 vs. f43 and Van Krevelen diagram (H/C vs. O/C) slopes similar to ambient oxidation, suggesting the PAM reactor employs oxidation pathways similar to ambient air. Single precursor aerosol yields were measured using the PAM reactor in the laboratory as a function of organic aerosol concentration and reacted hydrocarbon amounts. When applying the laboratory PAM yields with complete consumption of the most abundant VOCs measured at the forest site (monoterpenes, sesquiterpenes, MBO, and toluene), a simple model underpredicted the amount of SOA formed in the PAM reactor in the

  18. Toward new techniques to measure heterogeneous oxidation of aerosol: Electrodynamic Balance-Mass Spectrometry (EDB-MS) and Aerosol X-ray Photoelectron Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jacobs, M. I.; Heine, N.; Xu, B.; Davies, J. F.; Kirk, B. B.; Kostko, O.; Alayoglu, S.; Wilson, K. R.; Ahmed, M.

    2015-12-01

    The chemical composition and physical properties of aerosol can be changed via heterogeneous oxidation with the OH radical. However, the physical state of the aerosol influences the kinetics of this reaction; liquid particles with a high diffusion coefficient are expected to be well mixed and homogenously oxidized, while oxidation of solid, diffusion-limited aerosol is expected to occur primarily on the surface, creating steep chemical gradients within the particle. We are working to develop several new techniques to study the heterogeneous oxidation of different types of aerosol. We are developing a "modular" electrodynamic balance (EDB) that will enable us to study heterogeneous oxidation at aqueous interfaces using a mass-spectrometer (and potentially other detection techniques). Using a direct analysis in real time (DART) interface, preliminary droplet train measurements have demonstrated single-droplet mass spectrometry to be possible. With long reaction times in our EDB, we will be able to study heterogeneous oxidation of a wide variety of organic species in aqueous droplets. Additionally, we are working to use aerosol photoemission and velocity map imaging (VMI) to study the surface of aerosol particles as they undergo heterogeneous oxidation. With VMI, we're able to collect electrons with a 4π collection efficiency over conventional electron energy analyzers. Preliminary results looking at the ozonolysis of squalene using ultraviolet photoelectron spectroscopy (UPS) show that heterogeneous oxidation kinetic data can be extracted from photoelectron spectra. By moving to X-ray photoemission spectroscopy (XPS), we will determine elemental and chemical composition of the aerosol surface. Thus, aerosol XPS will provide information on the steep chemical gradients that form as diffusion-limited aerosol undergo heterogeneous oxidation.

  19. Temporal variations in sources and concentrations of black and organic carbon aerosols in the LA Basin

    NASA Astrophysics Data System (ADS)

    Mouteva, G.; Kearney, J.; Fahrni, S.; Santos, G. M.; Czimczik, C. I.

    2012-12-01

    Temporal variations in sources and concentrations of black and organic carbon aerosols in the LA Basin Black carbon (BC), derived from incomplete combustion of fossil and biogenic fuels and vegetation fires, is a crucial component of the aerosol pool, but sources as well as atmospheric transport and lifetime remain poorly constrained by measurements. We characterized the composition of carbonaceous aerosols emitted from urban areas by quantifying the temporal variations in the concentrations and sources of BC and organic carbon (OC) in PM-10 and PM-2.5 from two locations in the Los Angeles basin. Using the radiocarbon signatures in BC and OC allowed us to apportion emissions into fossil and modern contributions. We separated and quantified BC and OC using a modified Sunset OC-EC analyzer coupled to a vacuum line and cryogenically trapped the evolving CO2 (Zhang et al. In Prep.). The instrument and method were tested with well-defined radiocarbon standards to determine background, accuracy and precision. The purified CO2 was converted to graphite and measured at the Keck-AMS facility on unknown samples as small as ≥5 μg C. Preliminary results suggest that radiocarbon content can be used to apportion BC into fossil and modern sources. BC concentrations are on the order of 6-31% total carbon, with 48 to 96% fossil contribution. In the OC fraction we detected several super-modern samples, suggesting local production of radiocarbon, e.g. from medical waste incinerators. Thus, the radiocarbon-based approach cannot be used to quantify sources of OC and bulk carbonaceous aerosols in urban areas. Our measurements contribute to a comprehensive quantification of temporal and spatial variations in urban BC, a key uncertainty in constraining BC sources and transport in North America. References: Zhang YL, Perron N, Zotter P, Minguillón MC, Wacker L, Prévôt ASH, Baltensperger U, Szidat S. In Prep. On the isolation of OC and EC and the optimal strategy of radiocarbon

  20. Mammographic mass detection based on extended concentric morphology model

    NASA Astrophysics Data System (ADS)

    Li, Yanfeng; Chen, Houjin

    2014-01-01

    Breast cancer occurs with high frequency among women. In most cases, the main early signs appear as mass and calcification. Distinguishing masses from normal tissues is still a challenging work as mass varies with shapes, margins and sizes. In this paper, a novel method for mass detection in mammograms was presented. First, morphology operators are employed to locate mass candidates. Then anisotropic diffusion was applied to make mass region display better multiple concentric layers (MCL). Finally an extended concentric morphology model (ECMM) criterion combining MCL criterion and template matching was proposed to detect masses. This method was examined on 170 images from Digital Database for Screening Mammography (DDSM) database. The detection rate is 93.92% at 1.88 false positives per image (FPs/I), demonstrating the effectiveness of the proposed method.

  1. Variability of aerosol, gaseous pollutants and meteorological characteristics associated with continental, urban and marine air masses at the SW Atlantic coast of Iberia

    NASA Astrophysics Data System (ADS)

    Diesch, J.-M.; Drewnick, F.; Zorn, S. R.; von der Weiden-Reinmüller, S.-L.; Martinez, M.; Borrmann, S.

    2011-12-01

    Measurements of the ambient aerosol were performed at the Southern coast of Spain, within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from 20 November until 9 December 2008 at the atmospheric research station "El Arenosillo" (37°5'47.76" N, 6°44'6.94" W). As the monitoring station is located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean a variety of physical and chemical parameters of aerosols and gas phase could be characterized in dependency on the origin of air masses. Backwards trajectories were examined and compared with local meteorology to classify characteristic air mass types for several source regions. Aerosol number and mass as well as polycyclic aromatic hydrocarbons and black carbon concentrations were measured in PM1 and size distributions were registered covering a size range from 7 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (Aerodyne HR-ToF-AMS). Gas phase analyzers monitored various trace gases (O3, SO2, NO, NO2, CO2) and a weather station provided meteorological parameters. Lowest average submicron particle mass and number concentrations were found in air masses arriving from the Atlantic Ocean with values around 2 μg m-3 and 1000 cm-3. These mass concentrations were about two to four times lower than the values recorded in air masses of continental and urban origins. For some species PM1-fractions in marine air were significantly larger than in air masses originating from Huelva, a closely located city with extensive industrial activities. The largest fraction of sulfate (54%) was detected in marine air masses and was to a high degree not neutralized. In addition small concentrations of methanesulfonic acid (MSA), a product of biogenic dimethyl sulfate (DMS) emissions could be identified in the particle phase. In all

  2. Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

    SciTech Connect

    Kleinman L. I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek III, A. J.; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

    2012-01-04

    During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a boundary layer (BL) contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (D{sub p} > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25 % of aerosol with D{sub p} > 100 nm are interstitial (not activated). A direct comparison of pre-cloud and in-cloud aerosol yields a higher estimate. Artifacts in the measurement of interstitial aerosol due to droplet shatter and evaporation are discussed. Within each of 102 constant altitude cloud transects, CDNC and interstitial aerosol were anti-correlated. An examination of one cloud as a case study shows that the

  3. Submicron particle mass concentrations and sources in the Amazonian wet season (AMAZE-08)

    SciTech Connect

    Chen, Q.; Farmer, D. K.; Rizzo, L. V.; Pauliqueivis, T.; Kuwata, Mikinori; Karl, Thomas G.; Guenther, Alex B.; Allan, James D.; Coe, H.; Andreae, M. O.; Poeschl, U.; Jiminez, J. L.; Artaxo, Paulo; Martin, Scot T.

    2015-01-01

    Real-time mass spectra of non-refractory component of submicron aerosol particles were recorded in a tropical rainforest in the central Amazon basin during the wet season of 2008, as a part of the Amazonian Aerosol Characterization Experiment (AMAZE-08). Organic components accounted on average for more than 80% of the non-refractory submicron particle mass concentrations during the period of measurements. Ammonium was present in sufficient quantities to halfway neutralize sulfate. In this acidic, isoprene-dominated, low-NOx environment the high-resolution mass spectra as well as mass closures with ion chromatography measurements did not provide evidence for significant contributions of organosulfate species, at least at concentrations above uncertainty levels. Positive-matrix factorization of the time series of particle mass spectra identified four statistical factors to account for the variance of the signal intensities of the organic constituents: a factor HOA having a hydrocarbon-like signature and identified as regional emissions of primary organic material, a factor OOA-1 associated with fresh production of secondary organic material by a mechanism of BVOC oxidation followed by gas-to-particle conversion, a factor OOA-2 consistent with reactive uptake of isoprene oxidation products, especially epoxydiols by acidic particles, and a factor OOA-3 associated with long range transport and atmospheric aging. The OOA-1, -2, and -3 factors had progressively more oxidized signatures. Diameter-resolved mass spectral markers also suggested enhanced reactive uptake of isoprene oxidation products to the accumulation mode for the OOA-2 factor, and such size partitioning can be indicative of in-cloud process. The campaign-average factor loadings were in a ratio of 1.1:1.0 for the OOA-1 compared to the OOA-2 pathway, suggesting the comparable importance of gas-phase compared to particle-phase (including cloud waters) production pathways of secondary organic material during

  4. Estimation of surface-level PM concentration from satellite observation taking into account the aerosol vertical profiles and hygroscopicity.

    PubMed

    Kim, Kwanchul; Lee, Kwon H; Kim, Ji I; Noh, Youngmin; Shin, Dong H; Shin, Sung K; Lee, Dasom; Kim, Jhoon; Kim, Young J; Song, Chul H

    2016-01-01

    Surface-level PM10 distribution was estimated from the satellite aerosol optical depth (AOD) products, taking the account of vertical profiles and hygroscopicity of aerosols over Jeju, Korea during March 2008 and October 2009. In this study, MODIS AOD data from the Terra and Aqua satellites were corrected with aerosol extinction profiles and relative humidity data. PBLH (Planetary Boundary Layer Height) was determined from MPLNET lidar-derived aerosol extinction coefficient profiles. Through statistical analysis, better agreement in correlation (R = 0.82) between the hourly PM10 concentration and hourly average Sunphotometer AOD was the obtained when vertical fraction method (VFM) considering Haze Layer Height (HLH) and hygroscopic growth factor f(RH) was used. The validity of the derived relationship between satellite AOD and surface PM10 concentration clearly demonstrates that satellite AOD data can be utilized for remote sensing of spatial distribution of regional PM10 concentration.

  5. An observational study of night time aerosol concentrations in the lower atmosphere at a tropical coastal station

    NASA Astrophysics Data System (ADS)

    Parameswaran, K.; Rajeev, K.; Sen Gupta, K.

    1997-09-01

    Aerosol number densities in the lower troposphere measured by a bistatic CW lidar are used to study their altitude structure in the nocturnal mixing region and its association with stratified turbulence. In the early night hours the aerosol concentration shows a maximum just above the daytime Thermal Internal Boundary Layer. This maximum disappears in the late night hours. The integrated aerosol content in the first 1 km shows a general decrease during the post-midnight hours. Stratified aerosol layers are observed in the nocturnal mixing region during the post-midnight period. The association between these stratified aerosol layers and the prevailing atmospheric stability condition in this region is studied using the altitude profiles of different meteorological parameters obtained from pilot balloon and tethered balloonsonde observations.

  6. Surface acoustic-wave piezoelectric crystal aerosol mass microbalance

    NASA Astrophysics Data System (ADS)

    Bowers, W. D.; Chuan, R. L.

    1989-07-01

    The development of a particulate mass-sensing instrument based on a quartz-crystal microbalance and enhanced with the new surface acoustic-wave (SAW) technology is reported. Mass sensitivity comparisons of a 158-MHz SAW piezoelectric microbalance and a conventional 10-MHz quartz-crystal microbalance show that the SAW crystal is 266 times more sensitive, in good agreement with the theoretical value of 250. The frequency stability of a single SAW resonator is 6 parts in 10 to the 8th over 1 min. The response to temperature changes is found to be very linear over the range +30 to -30 C. A strong response to 15 ppm SO2 has been demonstrated on a chemically coated SAW crystal.

  7. High Resolution Mass Spectrometry of Seasonal Aerosol Samples From an Urban Location in the Italian Po Valley

    NASA Astrophysics Data System (ADS)

    Mahon, Brendan; Giorio, Chiara; Gallimore, Peter J.; Zielinski, Arthur T.; Tapparo, Andrea; Kalberer, Markus

    2016-04-01

    The Po Valley in Northern Italy represents one of the most polluted environments in Europe, with PM2.5 and ozone concentrations regularly exceeding 100μg/m3 and 50ppb respectively. Particularly during winter, prolonged inversion conditions together with biomass burning and anthropogenic emissions regularly lead to severe air pollution events. Over the course of several months in 2013-14, we carried out a sampling program at a city-centre site in Padova, Italy, collecting 24-hour high-volume aerosol filter samples, 18 in winter (mid December - mid March) and 20 in summer (late May - late July). Utilising high-resolution Orbitrap mass spectrometry techniques, we have characterised these sample sets to examine the long-term variation in aerosol composition over the sampling campaign and to determine the effect of anthropogenic gaseous pollutants such as NOx and SO2 on the composition of organic particle components. The results showed that between ca. 450-700 ions were measured in each sample in both the summer and winter sample sets, however the majority (90%) of ions in the winter samples were below 300m/z and below 380m/z in the summer samples. A much higher percentage of CHO-only ions were found in winter (ca. 27%) compared to the summer samples (ca. 6%), indicating a higher degree of photochemical reactions taking place involving pollutants such as NOx and SO2 in summer. Our results represent the first long term data set of high-resolution measurements of aerosol composition and demonstrate that this technique is an important tool in evaluating the composition of aerosol particles in complex polluted urban areas.

  8. Effect of variable power levels on the yield of total aerosol mass and formation of aldehydes in e-cigarette aerosols.

    PubMed

    Gillman, I G; Kistler, K A; Stewart, E W; Paolantonio, A R

    2016-03-01

    The study objective was to determine the effect of variable power applied to the atomizer of refillable tank based e-cigarette (EC) devices. Five different devices were evaluated, each at four power levels. Aerosol yield results are reported for each set of 25 EC puffs, as mass/puff, and normalized for the power applied to the coil, in mass/watt. The range of aerosol produced on a per puff basis ranged from 1.5 to 28 mg, and, normalized for power applied to the coil, ranged from 0.27 to 1.1 mg/watt. Aerosol samples were also analyzed for the production of formaldehyde, acetaldehyde, and acrolein, as DNPH derivatives, at each power level. When reported on mass basis, three of the devices showed an increase in total aldehyde yield with increasing power applied to the coil, while two of the devices showed the opposite trend. The mass of formaldehyde, acetaldehyde, and acrolein produced per gram of total aerosol produced ranged from 0.01 to 7.3 mg/g, 0.006 to 5.8 mg/g, and <0.003 to 0.78 mg/g, respectively. These results were used to estimate daily exposure to formaldehyde, acetaldehyde, and acrolein from EC aerosols from specific devices, and were compared to estimated exposure from consumption of cigarettes, to occupational and workplace limits, and to previously reported results from other researchers.

  9. Real-time measurement of sodium chloride in individual aerosol particles by mass spectrometry

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.; Friedlander, S. K.

    1985-01-01

    The method of particle analysis by mass spectrometry has been applied to the quantitative measurement of sodium chloride in individual particles on a real-time basis. Particles of known masses are individually introduced, in the form of a beam, into a miniature Knudsen cell oven (1600 K). The oven is fabricated from rhenium metal sheet (0.018 mm thick) and is situated in the ion source of a quadrupole mass spectrometer. A particle once inside the oven is trapped and completely volatilized; this overcomes the problem of partial volatilization due to particles bouncing from the filament surface. Individual particles are thermally volatilized and ionized inside the rhenium oven, and produce discrete sodium ion pulses whose intensities are measured with the quadrupole mass spectrometer. An ion pulse width of several milliseconds (4-12 ms) is found for particles in the mass range 1.3 x 10 to the -13th to 5.4 x 10 to the -11th g. The sodium ion intensity is found to be proportional to the particle mass to the 0.86-power. The intensity distribution for monodisperse aerosol particles possesses a geometric standard deviation of 1.09, showing that the method can be used for the determination of the mass distribution function with good resolution in a polydisperse aerosol.

  10. Molecular Characterization of Nitrogen Containing Organic Compounds in Biomass Burning Aerosols Using High Resolution Mass Spectrometry

    SciTech Connect

    Laskin, Alexander; Smith, Jeffrey S.; Laskin, Julia

    2009-05-13

    Although nitrogen-containing organic compounds (NOC) are important components of atmospheric aerosols, little is known about their chemical compositions. Here we present detailed characterization of the NOC constituents of biomass burning aerosol (BBA) samples using high resolution electrospray ionization mass spectrometry (ESI/MS). Accurate mass measurements combined with MS/MS fragmentation experiments of selected ions were used to assign molecular structures to individual NOC species. Our results indicate that N-heterocyclic alkaloid compounds - species naturally produced by plants and living organisms - comprise a substantial fraction of NOC in BBA samples collected from test burns of five biomass fuels. High abundance of alkaloids in test burns of ponderosa pine - a widespread tree in the western U.S. areas frequently affected by large scale fires - suggests that N-heterocyclic alkaloids in BBA can play a significant role in dry and wet deposition of fixed nitrogen in this region.

  11. Effect of aerosol number concentration on cloud droplet dispersion: A large-eddy simulation study and implications for aerosol indirect forcing

    NASA Astrophysics Data System (ADS)

    Lu, Miao-Ling; Seinfeld, John H.

    2006-01-01

    Through three-dimensional large-eddy simulations of marine stratocumulus we explore the factors that control the cloud spectral relative dispersion (ratio of cloud droplet spectral width to the mean radius of the distribution) as a function of aerosol number concentration and the extent to which the relative dispersion either enhances or mitigates the Twomey effect. We find that relative dispersion decreases with increasing aerosol number concentration (for aerosol number concentrations less than about 1000 cm-3) because smaller droplets resulting from higher aerosol number concentrations inhibit precipitation and lead to (1) less spectral broadening by suppressed collision and coalescence processes and (2) more spectral narrowing by droplet condensational growth at higher updraft velocity because reduced drizzle latent heating at cloud top results in increased boundary layer turbulent kinetic energy production by buoyancy and thereby stronger turbulence. Increased spectral broadening owing to increased cloud-top entrainment mixing, also as a result of increased boundary layer turbulence, is relatively insignificant compared with outcomes 1 and 2. The coefficient k, an important parameter that relates cloud droplet effective radius and volume mean radius in large-scale models, is a function of skewness and relative dispersion of the distribution and is negatively correlated with relative dispersion. Increasing k with increasing aerosol number concentration leads to maximum enhancement of the cloud susceptibility (the change of cloud optical depth due to change of cloud droplet number concentration) over that attributable to the Twomey effect alone by about 4.2% and 39% for simulated FIRE and ASTEX cases, respectively.

  12. Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

    SciTech Connect

    Kleinman, L.I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek III, A. J.; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

    2011-06-21

    During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate in agreement with the dominant pollution source being SO{sub 2} from Cu smelters and power plants. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a BL contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (Dp > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25% of aerosol in the PCASP size range are interstitial (not activated). One hundred and two constant altitude cloud transects were identified and used to determine properties of interstitial aerosol. One transect is examined in detail as a case study. Approximately 25 to 50% of aerosol with D{sub p} > 110 nm were not activated, the difference between the two

  13. Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

    NASA Astrophysics Data System (ADS)

    Kleinman, L. I.; Daum, P. H.; Lee, Y.-N.; Lewis, E. R.; Sedlacek, A. J., III; Senum, G. I.; Springston, S. R.; Wang, J.; Hubbe, J.; Jayne, J.; Min, Q.; Yum, S. S.; Allen, G.

    2011-06-01

    During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O3 and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate in agreement with the dominant pollution source being SO2 from Cu smelters and power plants. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 °C with dry air descending from the upper atmospheric and moist air having a BL contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (Dp > 100 nm) gives a linear relation up to a number concentration of ~150 cm-3, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that ~25 % of aerosol in the PCASP size range are interstitial (not activated). One hundred and two constant altitude cloud transects were identified and used to determine properties of interstitial aerosol. One transect is examined in detail as a case study. Approximately 25 to 50 % of aerosol with Dp > 110 nm were not activated, the difference between the two approaches possibly representing

  14. Acid and organic aerosol coatings on magnetic nanoparticles increase iron concentrations in human airway epithelial cells.

    PubMed

    Ghio, Andrew J; Dailey, Lisa A; Richards, Judy H; Jang, Myoseon

    2009-07-01

    Numerous industrial applications for man-made nanoparticles have been proposed. Interactions of nanoparticles with agents in the atmosphere may impact human health. We tested the postulate that in vitro exposures of respiratory epithelial cells to airborne magnetic nanoparticles (MNP; Fe(3)O(4)) with and without a secondary organic aerosol (SOA) and an inorganic acid could affect iron homeostasis, oxidative stress, and interleukin (IL)-8 release. Cell iron concentrations were increased after exposures to MNP and values were further elevated with co-exposures to either SOA or inorganic acid. Increased expression of ferritin and elevated levels of RNA for DMT1, proteins for iron storage and transport respectively, followed MNP exposures, but values were significant for only those with co-exposures to inorganic acid and organic aerosols. Cell iron concentration corresponded to a measure of oxidative stress in the airway epithelial cells; MNP with co-exposures to SOA and inorganic acid increased both available metal and indices of oxidant generation. Finally, the release of a proinflammatory cytokine (i.e. IL-8) by the exposed cells similarly increased with cell iron concentration. We conclude that MNP can interact with a SOA and an inorganic acid to present metal in a catalytically reactive state to cultured respiratory cells. This produces an oxidative stress to affect a release of IL-8.

  15. Analysis of charged aerosols in the mesosphere during the MASS/ECOMA rocket campaign

    NASA Astrophysics Data System (ADS)

    Knappmiller, Scott Robert

    In the polar summer mesosphere ice particles grow sufficiently large to scatter sunlight, giving rise to visible cloud displays called Noctilucent Clouds (NLC). In August of 2007, two sounding rockets were launched from the Andoya Rocket Range, Norway carrying the newly developed MASS instrument (Mesospheric Aerosol Sampling Spectrometer) to study NLC. The instrument detects charged aerosols in four different mass ranges on four pairs of biased collector plates, one set for positive particles and one set for negative particles. The first sounding rocket was launched into a Polar Mesospheric Summer echo (PMSE) and into a NLC on 3 August. The solar zenith angle was 93 degrees and NLC were seen in the previous hour at 83 km by the ALOMAR RMR lidar. NLC were also detected at the same altitude by rocket-borne photometer measurements. The data from the MASS instrument shows a negatively charged population with radii >3 nm in the 83--89 km altitude range, which is collocated with PMSE detected by the ALWIN radar. Smaller particles, 1--2 nm in radius with both positive and negative polarity were detected between 86--88 km. Positively charged particles <1 nm in radius were detected at the same altitude. This is the first time the charge number densities of positive and negative NLC particles have been measured simultaneously. A charging model is developed to investigate the coexistence of positively and negatively charged aerosols in the NLC environment as measured by the MASS instrument. Natanson's rate equations are used for the attachment of free electrons and ions and the model includes charging by photo-electron emission and photo-detachment. Although the MASS flight occurred during twilight conditions, the solar UV flux was still sufficient to affect the charge state of the aerosols. The calculations are done assuming three types of particles with different photo-electron charging properties: (1) Icy NLC particles, (2) Hematite particles of meteoric origin as

  16. CHEMICAL ANALYSIS METHODS FOR ATMOSPHERIC AEROSOL COMPONENTS

    EPA Science Inventory

    This chapter surveys the analytical techniques used to determine the concentrations of aerosol mass and its chemical components. The techniques surveyed include mass, major ions (sulfate, nitrate, ammonium), organic carbon, elemental carbon, and trace elements. As reported in...

  17. Development of the RAQM2 aerosol chemical transport model and predictions of the Northeast Asian aerosol mass, size, chemistry, and mixing type

    NASA Astrophysics Data System (ADS)

    Kajino, M.; Inomata, Y.; Sato, K.; Ueda, H.; Han, Z.; An, J.; Katata, G.; Deushi, M.; Maki, T.; Oshima, N.; Kurokawa, J.; Ohara, T.; Takami, A.; Hatakeyama, S.

    2012-12-01

    A new aerosol chemical transport model, the Regional Air Quality Model 2 (RAQM2), was developed to simulate the Asian air quality. We implemented a simple version of a triple-moment modal aerosol dynamics model (MADMS) and achieved a completely dynamic (non-equilibrium) solution of a gas-to-particle mass transfer over a wide range of aerosol diameters from 1 nm to super-μm. To consider a variety of atmospheric aerosol properties, a category approach was utilized in which the aerosols were distributed into four categories: particles in the Aitken mode (ATK), soot-free particles in the accumulation mode (ACM), soot aggregates (AGR), and particles in the coarse mode (COR). The aerosol size distribution in each category is characterized by a single mode. The condensation, evaporation, and Brownian coagulations for each mode were solved dynamically. A regional-scale simulation (Δx = 60 km) was performed for the entire year of 2006 covering the Northeast Asian region. The modeled PM1/bulk ratios of the chemical components were consistent with observations, indicating that the simulated aerosol mixing types were consistent with those in nature. The non-sea-salt SO42- mixed with ATK + ACM was the largest at Hedo in summer, whereas the SOSO42- was substantially mixed with AGR in the cold seasons. Ninety-eight percent of the modeled NO3- was mixed with sea salt at Hedo, whereas 53.7% of the NO3- was mixed with sea salt at Gosan, which is located upwind toward the Asian continent. The condensation of HNO3 onto sea salt particles during transport over the ocean accounts for the difference in the NO3- mixing type at the two sites. Because the aerosol mixing type alters the optical properties and cloud condensation nuclei activity, its accurate prediction and evaluation are indispensable for aerosol-cloud-radiation interaction studies.

  18. Aerosol mass spectrometer for the in situ analysis of chemical vapor synthesis processes in hot wall reactors

    NASA Astrophysics Data System (ADS)

    Lee, In-Kyum; Winterer, Markus

    2005-09-01

    We present a modified aerosol mass spectrometer (AMS) for the in situ analysis of chemical vapor synthesis processes in hot wall reactors and describe the transfer function of the velocity and kinetic-energy measurement. The AMS is a combination of a quadrupole mass spectrometer (QMS) and a particle mass spectrometer (PMS) and enables the in situ analysis of aerosols with high number concentrations up to 1018m-3. Size distributions of ultrafine particles in the range of 104-107u (amu) can be measured in the PMS. Simultaneously, molecular species up to 300u can be detected in the QMS. In the setup described here a furnace was developed to enable measurement directly at the reactor exit. The formation of silicon carbide (SiC) nanoparticles by thermal decomposition of tetramethylsilane (TMS) was investigated. TMS started to decompose at about 900K and carbosilanes with two [-Si-C-] units were identified as growth species in the synthesis of SiC from TMS. With increasing temperatures particles were formed and grew by coagulation. At higher temperatures sintering of the particles became an important process. Although the particle mass reduced slightly due to a smaller residence time at higher temperatures in the reactor, the particle velocity in the molecular beam of the AMS decreased significantly. A simple model is used to compare the particle velocity in a molecular beam as a function of particle mass. The significant difference in the particle velocity can be explained by a change in the particle shape factor (κp) due to sintering.

  19. Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

    SciTech Connect

    McJimpsey, E L; Steele, P T; Coffee, K R; Fergenson, D P; Riot, V J; Woods, B W; Gard, E E; Frank, M; Tobias, H J; Lebrilla, C

    2006-03-16

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described.

  20. 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

  1. 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

  2. Size-Segregated Aerosol Composition and Mass Loading of Atmospheric Particles as Part of the Pacific Northwest 2001(PNW2001) Air Quality Study In Puget Sound

    NASA Astrophysics Data System (ADS)

    Disselkamp, R. S.; Barrie, L. A.; Shutthanadan, S.; Cliff, S.; Cahill, T.

    2001-12-01

    In mid-August, 2001, an aircraft-based air-quality study was performed in the Puget Sound, WA, area entitled PNW2001 (http://www.pnl.gov/pnw2001). The objectives of this field campaign were the following: 1. reveal information about the 3-dimensional distribution of ozone, its gaseous precursors and fine particulate matter during weather conditions favoring air pollution; 2. derive information about the accuracy of urban and biogenic emissions inventories that are used to drive the air quality forecast models; and 3. examine the accuracy of modeled ozone concentration with that observed. In support of these efforts, we collected time-averaged ( { ~}10 minute averages), size-segregated, aerosol composition and mass-loading information using ex post facto analysis techniques of synchrotron x-ray fluorescence (s-XRF), proton induced x-ray emissions(PIXE), proton elastic scattering (PESA), and scanning transmission ion microscopy (STIM). This is the first time these analysis techniques have been used together on samples collected from aircraft using an optimized 3-stage rotating drum impactor. In our presentation, we will discuss the aerosol components in three aerosol size fractions as identified by statistical analysis of multielemental data (including total mass, H, Na, Mg, Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Pb) and relate variations in these components to physical aerosol properties, other gaseous trace constituents and to air mass origin.

  3. Corrigendum to "Chemical apportionment of southern African aerosol mass and optical depth" published in Atmos. Chem. Phys., 9, 7643-7655, 2009

    NASA Astrophysics Data System (ADS)

    Magi, B. I.

    2011-05-01

    A correction to results by Magi (2009) is presented here. By combining the in situ measurements of speciated aerosol mass concentrations with concurrent measurements of total aerosol optical properties at a wavelength of 550 nm, it is shown that ~66 % of scattering is due to carbonaceous aerosol, where derived mass scattering cross sections (MSC) for OC and BC are 3.8 ± 0.5 m2 g-1 and 2.9 ± 0.8 m2 g-1, respectively. Derived values of mass absorption cross sections (MAC) for OC and BC are 0.7 ± 0.2 m2 g-1 and 12.1 ± 0.8 m2 g-1, respectively. The values of MAC imply that ~21 % of the mid-visible aerosol absorption in southern Africa is due to OC, with the remainder due to BC. SSA for BC and OC are about the same as Magi (2009). The results here are determined using an approach that accounts for the fact that OC and BC are partially scattering and absorbing.

  4. Ambient particle characterization by single particle aerosol mass spectrometry in an urban area of Beijing

    NASA Astrophysics Data System (ADS)

    Li, Lei; Li, Mei; Huang, Zhengxu; Gao, Wei; Nian, Huiqing; Fu, Zhong; Gao, Jian; Chai, Fahe; Zhou, Zhen

    2014-09-01

    To investigate the composition and possible sources of aerosol particles in Beijing urban area, a single particle aerosol mass spectrometer (SPAMS) was deployed from April 22 to May 4, 2011. 510,341 particles out of 2,953,200 sized particles were characterized by SPAMS in combination with the ART-2a neural network algorithm. The particles were classified as rich-K (39.79%), carbonaceous species (32.7%), industry metal (19.2%), dust (5.7%), and rich-Na (1.76%). Industrial emissions related particles, rich-Fe, rich-Pb, and K-nitrate, were the major components of aerosol particles during haze periods, which were mainly from the steel plants and metal smelting processes around Beijing. Under stagnant meterological conditions, these regional emissions have a vital effect on haze formation. Organic carbon (OC) particles were attributed to biomass burning. NaK-EC was likely to come from local traffic emissions. Internally mixed organic and elemental carbon (OCEC) was found to be from possible sources of local traffic emission and biomass burning. It was found that coarse dust particles were mainly composed of four different types of dust particles, dust-Si, dust-Ca, dust-Al, and dust-Ti. It is the first time that SPAMS was used to study a dust storm in Beijing. Our results showed that SPAMS could be a powerful tool in the identification and apportionment of aerosol sources in Beijing, providing useful reference information for environmental control and management.

  5. 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

  6. 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.

  7. Vibration analysis of rotor blades with an attached concentrated mass

    NASA Technical Reports Server (NTRS)

    Murthy, V. R.; Barna, P. S.

    1977-01-01

    The effect of an attached concentrated mass on the dynamics of helicopter rotor blades is determined. The point transmission matrix method was used to define, through three completely automated computer programs, the natural vibrational characteristics (natural frequencies and mode shapes) of rotor blades. The problems of coupled flapwise bending, chordwise bending, and torsional vibration of a twisted nonuniform blade and its special subcase pure torsional vibration are discussed. The orthogonality relations that exist between the natural modes of rotor blades with an attached concentrated mass are derived. The effect of pitch, rotation, and point mass parameters on the collective, cyclic, scissor, and pure torsional modes of a seesaw rotor blade is determined.

  8. Evaluation of the tropospheric aerosol number concentrations simulated by two versions of the global model ECHAM5-HAM

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Kazil, J.; Feichter, J.

    2009-04-01

    Since its first version developed by Stier et al. (2005), the global aerosol-climate model ECHAM5-HAM has gone through further development and updates. The changes in the model include (1) a new time integration scheme for the condensation of the sulfuric acid gas on existing particles, (2) a new aerosol nucleation scheme that takes into account the charged nucleation caused by cosmic rays, and (3) a parameterization scheme explicitly describing the conversion of aerosol particles to cloud nuclei. In this work, simulations performed with the old and new model versions are evaluated against some measurements reported in recent years. The focus is on the aerosol size distribution in the troposphere. Results show that modifications in the parameterizations have led to significant changes in the simulated aerosol concentrations. Vertical profiles of the total particle number concentration (diameter > 3nm) compiled by Clarke et al. (2002) suggest that, over the Pacific in the upper free troposphere, the tropics are associated with much higher concentrations than the mid-latitude regions. This feature is more reasonably reproduced by the new model version, mainly due to the improved results of the nucleation mode aerosols. In the lower levels (2-5 km above the Earth's surface), the number concentrations of the Aitken mode particles are overestimated compared to both the Pacific data given in Clarke et al. (2002) and the vertical profiles over Europe reported by Petzold et al. (2007). The physical and chemical processes that have led to these changes are identified by sensitivity tests. References: Clarke and Kapustin: A Pacific aerosol survey - part 1: a decade of data on production, transport, evolution and mixing in the troposphere, J. Atmos. Sci., 59, 363-382, 2002. Petzold et al.: Perturbation of the European free troposphere aerosol by North American forest fire plumes during the ICARTT-ITOP experiment in summer 2004, Atmos. Chem. Phys., 7, 5105-5127, 2007

  9. Aerosol Mass Spectrometry via Laser-Induced Incandescence Particle Vaporization Final Report

    SciTech Connect

    Timothy B. Onasch

    2011-10-20

    We have successfully developed and commercialized a soot particle aerosol mass spectrometer (SP-AMS) instrument to measure mass, size, and chemical information of soot particles in ambient environments. The SP-AMS instrument has been calibrated and extensively tested in the laboratory and during initial field studies. The first instrument paper describing the SP-AMS has been submitted for publication in a peer reviewed journal and there are several related papers covering initial field studies and laboratory studies that are in preparation. We have currently sold 5 SP-AMS instruments (either as complete systems or as SP modules to existing AMS instrument operators).

  10. Chemical Nature Of Titan’s Organic Aerosols Constrained from Spectroscopic and Mass Spectrometric Observations

    NASA Astrophysics Data System (ADS)

    Imanaka, Hiroshi; Cruikshank, D. P.

    2012-10-01

    The Cassini-Huygens observations greately extend our knowledge about Titan’s organic aerosols. The Cassini INMS and CAPS observations clearly demonstrate the formation of large organic molecules in the ionosphere [1, 2]. The VIMS and CIRS instruments have revealed spectral features of the haze covering the mid-IR and far-IR wavelengths [3, 4, 5, 6]. This study attempts to speculate the possible chemical nature of Titan’s aerosols by comparing the currently available observations with our laboratory study. We have conducted a series of cold plasma experiment to investigate the mass spectrometric and spectroscopic properties of laboratory aerosol analogs [7, 8]. Titan tholins and C2H2 plasma polymer are generated with cold plasma irradiations of N2/CH4 and C2H2, respectively. Laser desorption mass spectrum of the C2H2 plasma polymer shows a reasonable match with the CAPS positive ion mass spectrum. Furthermore, spectroscopic features of the the C2H2 plasma polymer in mid-IR and far-IR wavelegths qualitatively show reasonable match with the VIMS and CIRS observations. These results support that the C2H2 plasma polymer is a good candidate material for Titan’s aerosol particles at the altitudes sampled by the observations. We acknowledge funding supports from the NASA Cassini Data Analysis Program, NNX10AF08G, and from the NASA Exobiology Program, NNX09AM95G, and the Cassini Project. [1] Waite et al. (2007) Science 316, 870-875. [2] Crary et al. (2009) Planet. Space Sci. 57, 1847-1856. [3] Bellucci et al. (2009) Icarus 201, 198-216. [4] Anderson and Samuelson (2011) Icarus 212, 762-778. [5] Vinatier et al. (2010) Icarus 210, 852-866. [6] Vinatier et al. (2012) Icarus 219, 5-12. [7] Imanaka et al. (2004) Icarus 168, 344-366. [8] Imanaka et al. (2012) Icarus 218, 247-261.

  11. Characterization of solvent-extractable organics in urban aerosols based on mass spectrum analysis and hygroscopic growth measurement.

    PubMed

    Mihara, Toshiyuki; Mochida, Michihiro

    2011-11-01

    To characterize atmospheric particulate organics with respect to polarity, aerosol samples collected on filters in the urban area of Nagoya, Japan, in 2009 were extracted using water, methanol, and ethyl acetate. The extracts were atomized and analyzed using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a hygroscopicity tandem differential mobility analyzer. The atmospheric concentrations of the extracted organics were determined using phthalic acid as a reference material. Comparison of the organic carbon concentrations measured using a carbon analyzer and the HR-ToF-AMS suggests that organics extracted with water (WSOM) and ethyl acetate (EASOM) or those extracted with methanol (MSOM) comprise the greater part of total organics. The oxygen-carbon ratios (O/C) of the extracted organics varied: 0.51-0.75 (WSOM), 0.37-0.48 (MSOM), and 0.27-0.33 (EASOM). In the ion-group analysis, WSOM, MSOM, and EASOM were clearly characterized by the different fractions of the CH and CO(2) groups. On the basis of the hygroscopic growth measurements of the extracts, κ of organics at 90% relative humidity (κ(org)) were estimated. Positive correlation of κ(org) with O/C (r 0.70) was found for MSOM and EASOM, but no clear correlation was found for WSOM.

  12. 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

  13. Control of aerosol contaminants in indoor air: combining the particle concentration reduction with microbial inactivation.

    PubMed

    Grinshpun, Sergey A; Adhikari, Atin; Honda, Takeshi; Kim, Ki Youn; Toivola, Mika; Rao, K S Ramchander; Reponen, Tiina

    2007-01-15

    An indoor air purification technique, which combines unipolar ion emission and photocatalytic oxidation (promoted by a specially designed RCI cell), was investigated in two test chambers, 2.75 m3 and 24.3 m3, using nonbiological and biological challenge aerosols. The reduction in particle concentration was measured size selectively in real-time, and the Air Cleaning Factor and the Clean Air Delivery Rate (CADR) were determined. While testing with virions and bacteria, bioaerosol samples were collected and analyzed, and the microorganism survival rate was determined as a function of exposure time. We observed that the aerosol concentration decreased approximately 10 to approximately 100 times more rapidly when the purifier operated as compared to the natural decay. The data suggest that the tested portable unit operating in approximately 25 m3 non-ventilated room is capable to provide CADR-values more than twice as great than the conventional closed-loop HVAC system with a rating 8 filter. The particle removal occurred due to unipolar ion emission, while the inactivation of viable airborne microorganisms was associated with photocatalytic oxidation. Approximately 90% of initially viable MS2 viruses were inactivated resulting from 10 to 60 min exposure to the photocatalytic oxidation. Approximately 75% of viable B. subtilis spores were inactivated in 10 min, and about 90% or greater after 30 min. The biological and chemical mechanisms that led to the inactivation of stress-resistant airborne viruses and bacterial spores were reviewed.

  14. Changes in the concentration and composition of anthropogenic and biogenic aerosols in the Finnish Arctic

    NASA Astrophysics Data System (ADS)

    Yli-Tuomi, Tarja

    In this study, historical samples of Arctic haze collected between 1964 and 1978 from northern Finland have been analyzed. The aim has been to determine the sources of the particles, as well as the temporal variation in the source contributions and the source regions. There is no other long-term data available from this early time period and overall, more information about the occurrence, nature, origin and transport of anthropogenic and biogenic aerosols in the European Arctic is needed in order to protect the vulnerable Arctic environment. In addition, evidence for climate/biosphere interaction observed in a previous study of the Arctic aerosol has been sought. The chemical composition data was analyzed with a Multilinear Engine using two different models, pure bilinear and a mixed 2-way/3-way model. The results of receptor modeling were connected with back trajectory data in a Potential Source Contribution Function analysis to determine the likely source areas. Nine sources, namely silver emissions, coal combustion, biomass burning, nonferrous smelters (two sources), crustal elements from remote sources, excess silicon from local sources, sea salt particles and biogenic sulfur emissions from marine algae were found. Although the emissions from industrial areas in the Kola Peninsula have an effect on the concentration of anthropogenic pollutants at Kevo, the highest concentrations during winter are transported from the sources in the mid-latitudes. The yearly strength of the biogenic sulfur emissions showed no dependence on the Northern Hemisphere temperature anomaly and thus, a climatic feedback loop can not be confirmed.

  15. Fluorescent Biological Aerosol Particle Concentrations and Size Distributions Measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS) in Central Europe

    NASA Astrophysics Data System (ADS)

    Huffman, J. A.; Treutlein, B.; Pöschl, U.

    2009-12-01

    Primary biological aerosol particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany, we used an ultraviolet aerodynamic particle sizer (UV-APS) to measure fluorescent biological aerosol particles (FBAPs), which can be regarded as viable bioaerosol particles representing a lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (< 1 µm), but not for coarse particles (1 - 20 µm). Averaged over the four-month measurement period (August - December 2006), the mean number concentration of coarse FBAPs was ~3x10-2 cm-3, corresponding to ~4% of total coarse particle number [1]. The mean mass concentration of FBAPs was ~1 µg m-3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 µm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 µm, geometric standard deviation 1.3, number concentration 1.6 x 10-2 cm-3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 µm, ~5 µm, and ~13 µm were also observed, but less pronounced and less frequent. These may be explained by single bacterial cells, larger fungal spores, and pollen grains, respectively. The observed number concentrations and characteristic sizes of FBAPs are consistent with microscopic, biological and chemical analyses of

  16. Fluorescent biological aerosol particle concentrations and size distributions measured with an ultraviolet aerodynamic particle sizer (UV-APS) in Central Europe

    NASA Astrophysics Data System (ADS)

    Huffman, J. A.; Treutlein, B.; Pöschl, U.

    2009-08-01

    Primary biological aerosol particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany, we used an ultraviolet aerodynamic particle sizer (UV-APS) to measure fluorescent biological aerosol particles (FBAPs), which can be regarded as viable bioaerosol particles representing a lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (<1 μm), but not for coarse particles (1-20 μm). Averaged over the four-month measurement period (August-December 2006), the mean number concentration of coarse FBAPs was ~3×10-2 cm-3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1 μg m-3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10-2 cm-3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be explained by single bacterial cells, larger fungal spores, and pollen grains, respectively. The observed number concentrations and characteristic sizes of FBAPs are consistent with microscopic, biological and chemical analyses of PBAPs in

  17. Fluorescent biological aerosol particle concentrations and size distributions measured with an Ultraviolet Aerodynamic Particle Sizer (UV-APS) in Central Europe

    NASA Astrophysics Data System (ADS)

    Huffman, J. A.; Treutlein, B.; Pöschl, U.

    2010-04-01

    Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen, are essential for the spread of organisms and disease in the biosphere, and numerous studies have suggested that they may be important for atmospheric processes, including the formation of clouds and precipitation. The atmospheric abundance and size distribution of PBAPs, however, are largely unknown. At a semi-urban site in Mainz, Germany we used an Ultraviolet Aerodynamic Particle Sizer (UV-APS) to measure Fluorescent Biological Aerosol Particles (FBAPs), which provide an estimate of viable bioaerosol particles and can be regarded as an approximate lower limit for the actual abundance of PBAPs. Fluorescence of non-biological aerosol components are likely to influence the measurement results obtained for fine particles (<1 μm), but not for coarse particles (1-20 μm). Averaged over the four-month measurement period (August-December 2006), the mean number concentration of coarse FBAPs was ~3×10-2 cm-3, corresponding to ~4% of total coarse particle number. The mean mass concentration of FBAPs was ~1μg m-3, corresponding to ~20% of total coarse particle mass. The FBAP number size distributions exhibited alternating patterns with peaks at various diameters. A pronounced peak at ~3 μm was essentially always observed and can be described by the following campaign-average lognormal fit parameters: geometric mean diameter 3.2 μm, geometric standard deviation 1.3, number concentration 1.6×10-2 cm-3. This peak is likely due to fungal spores or agglomerated bacteria, and it exhibited a pronounced diel cycle (24-h) with maximum intensity during early/mid-morning. FBAP peaks around ~1.5 μm, ~5 μm, and ~13 μm were also observed, but less pronounced and less frequent. These may be single bacterial cells, larger fungal spores, and pollen grains, respectively. The observed number concentrations and characteristic sizes of FBAPs are consistent with microscopic, biological and chemical

  18. The importance of aerosol mixing state and size-resolved composition on CCN concentration and the variation of the importance with atmospheric aging of aerosols

    SciTech Connect

    Wang, J.; Cubison, M. J.; Aiken, A. C.; Jimenez, J. L.; Collins, D. R.

    2010-05-01

    Aerosol microphysics, chemical composition, and CCN concentrations were measured at the T0 urban supersite in Mexico City during Megacity Initiative: Local and Global Research Observations (MILAGRO) in March 2006. The aerosol size distribution and composition often showed strong diurnal variation associated with traffic emissions and aging of aerosols through coagulation and local photochemical production of secondary aerosol species. CCN concentrations (N{sub CCN}) are derived using Kohler theory from the measured aerosol size distribution and various simplified aerosol mixing state and chemical composition, and are compared to concurrent measurements at five supersaturations ranging from 0.11% to 0.35%. The influence of assumed mixing state on calculated N{sub CCN} is examined using both aerosols observed during MILAGRO and representative aerosol types. The results indicate that while ambient aerosols often consist of particles with a wide range of compositions at a given size, N{sub CCN} may be derived within {approx}20% assuming an internal mixture (i.e., particles at a given size are mixtures of all participating species, and have the identical composition) if great majority of particles has an overall {kappa} (hygroscopicity parameter) value greater than 0.1. For a non-hygroscopic particle with a diameter of 100 nm, a 3 nm coating of sulfate or nitrate is sufficient to increase its {kappa} from 0 to 0.1. The measurements during MILAGRO suggest that the mixing of non-hygroscopic primary organic aerosol (POA) and black carbon (BC) particles with photochemically produced hygroscopic species and thereby the increase of their {kappa} to 0.1 take place in a few hours during daytime. This rapid process suggests that during daytime, a few tens of kilometers away for POA and BC sources, N{sub CCN} may be derived with sufficient accuracy by assuming an internal mixture, and using bulk chemical composition. The rapid mixing also indicates that, at least for very active

  19. Secondary organic aerosol formation from fossil fuel sources contribute majority of summertime organic mass at Bakersfield

    NASA Astrophysics Data System (ADS)

    Liu, Shang; Ahlm, Lars; Day, Douglas A.; Russell, Lynn M.; Zhao, Yunliang; Gentner, Drew R.; Weber, Robin J.; Goldstein, Allen H.; Jaoui, Mohammed; Offenberg, John H.; Kleindienst, Tadeusz E.; Rubitschun, Caitlin; Surratt, Jason D.; Sheesley, Rebecca J.; Scheller, Scott

    2012-12-01

    Secondary organic aerosols (SOA), known to form in the atmosphere from oxidation of volatile organic compounds (VOCs) emitted by anthropogenic and biogenic sources, are a poorly understood but substantial component of atmospheric particles. In this study, we examined the chemical and physical properties of SOA at Bakersfield, California, a site influenced by anthropogenic and terrestrial biogenic emissions. Factor analysis was applied to the infrared and mass spectra of fine particles to identify sources and atmospheric processing that contributed to the organic mass (OM). We found that OM accounted for 56% of submicron particle mass, with SOA components contributing 80% to 90% of OM from 15 May to 29 June 2010. SOA formed from alkane and aromatic compounds, the two major classes of vehicle-emitted hydrocarbons, accounted for 65% OM (72% SOA). The alkane and aromatic SOA components were associated with 200 nm to 500 nm accumulation mode particles, likely from condensation of daytime photochemical products of VOCs. In contrast, biogenic SOA likely formed from condensation of secondary organic vapors, produced from NO3radical oxidation reactions during nighttime hours, on 400 nm to 700 nm sized primary particles, and accounted for less than 10% OM. Local petroleum operation emissions contributed 13% to the OM, and the moderate O/C (0.2) of this factor suggested it was largely of secondary origin. Approximately 10% of organic aerosols in submicron particles were identified as either vegetative detritus (10%) or cooking activities (7%), from Fourier transform infrared spectroscopic and aerosol mass spectrometry measurements, respectively. While the mass spectra of several linearly independent SOA components were nearly identical and external source markers were needed to separate them, each component had distinct infrared spectrum, likely associated with the source-specific VOCs from which they formed.

  20. Study of node and mass sensitivity of resonant mode based cantilevers with concentrated mass loading

    SciTech Connect

    Zhang, Kewei Chai, Yuesheng; Fu, Jiahui

    2015-12-15

    Resonant-mode based cantilevers are an important type of acoustic wave based mass-sensing devices. In this work, the governing vibration equation of a bi-layer resonant-mode based cantilever attached with concentrated mass is established by using a modal analysis method. The effects of resonance modes and mass loading conditions on nodes and mass sensitivity of the cantilever were theoretically studied. The results suggested that the node did not shift when concentrated mass was loaded on a specific position. Mass sensitivity of the cantilever was linearly proportional to the square of the point displacement at the mass loading position for all the resonance modes. For the first resonance mode, when mass loading position x{sub c} satisfied 0 < x{sub c} < ∼ 0.3l (l is the cantilever beam length and 0 represents the rigid end), mass sensitivity decreased as the mass increasing while the opposite trend was obtained when mass loading satisfied ∼0.3l ≤ x{sub c} ≤ l. Mass sensitivity did not change when concentrated mass was loaded at the rigid end. This work can provide scientific guidance to optimize the mass sensitivity of a resonant-mode based cantilever.

  1. Development of Soft Ionization for Particulate Organic Detection with the Aerodyne Aerosol Mass Spectrometer

    SciTech Connect

    Trimborn, A; Williams, L R; Jayne, J T; Worsnop, D R

    2008-06-19

    During this DOE SBIR Phase II project, we have successfully developed several soft ionization techniques, i.e., ionization schemes which involve less fragmentation of the ions, for use with the Aerodyne time-of-flight aerosol mass spectrometer (ToF-AMS). Vacuum ultraviolet single photon ionization was demonstrated in the laboratory and deployed in field campaigns. Vacuum ultraviolet single photon ionization allows better identification of organic species in aerosol particles as shown in laboratory experiments on single component particles, and in field measurements on complex multi-component particles. Dissociative electron attachment with lower energy electrons (less than 30 eV) was demonstrated in the measurement of particulate organics in chamber experiments in Switzerland, and is now a routine approach with AMS systems configured for bipolar, negative ion detection. This technique is particularly powerful for detection of acidic and other highly oxygenated secondary organic aerosol (SOA) chemical functionality. Low energy electron ionization (10 to 12 eV) is also a softer ionization approach routinely available to AMS users. Finally, Lithium ion attachment has been shown to be sensitive to more alkyl-like chemical functionality in SOA. Results from Mexico City are particularly exciting in observing changes in SOA molecular composition under different photochemical/meteorological conditions. More recent results detecting biomass burns at the Montana fire lab have demonstrated quantitative and selective detection of levoglucosan. These soft ionization techniques provide the ToF-AMS with better capability for identifying organic species in ambient atmospheric aerosol particles. This, in turn, will allow more detailed study of the sources, transformations and fate of organic-containing aerosol.

  2. Worldwide impact of aerosol's time scale on the predicted long-term concentrating solar power potential.

    PubMed

    Ruiz-Arias, Jose A; Gueymard, Christian A; Santos-Alamillos, Francisco J; Pozo-Vázquez, David

    2016-08-10

    Concentrating solar technologies, which are fuelled by the direct normal component of solar irradiance (DNI), are among the most promising solar technologies. Currently, the state-of the-art methods for DNI evaluation use datasets of aerosol optical depth (AOD) with only coarse (typically monthly) temporal resolution. Using daily AOD data from both site-specific observations at ground stations as well as gridded model estimates, a methodology is developed to evaluate how the calculated long-term DNI resource is affected by using AOD data averaged over periods from 1 to 30 days. It is demonstrated here that the use of monthly representations of AOD leads to systematic underestimations of the predicted long-term DNI up to 10% in some areas with high solar resource, which may result in detrimental consequences for the bankability of concentrating solar power projects. Recommendations for the use of either daily or monthly AOD data are provided on a geographical basis.

  3. Ozone and aerosol tropospheric concentrations variability analyzed using the ADRIMED measurements and the WRF and CHIMERE models

    NASA Astrophysics Data System (ADS)

    Menut, L.; Mailler, S.; Siour, G.; Bessagnet, B.; Turquety, S.; Rea, G.; Briant, R.; Mallet, M.; Sciare, J.; Formenti, P.; Meleux, F.

    2015-06-01

    During the months of June and July 2013, over the Euro-Mediterranean area, the ADRIMED (Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) project was dedicated to characterize the ozone and aerosol concentrations in the troposphere. It is first shown that this period was not highly polluted compared to previous summers in this region, with a moderate ozone production, no significant vegetation fire events and several precipitation periods scavenging the aerosol. The period is modeled with the WRF (Weather Research and Forecasting) and CHIMERE models, and their ability to quantify the observed pollution transport events is presented. The CHIMERE model simulating all kinds of sources (anthropogenic, biogenic, mineral dust, vegetation fires); the aerosol speciation, not available with the measurements, is presented: during the whole period, the aerosol was mainly constituted by mineral dust, sea salt and sulfates close to the surface and mainly by mineral dust in the troposphere. Compared to the AERONET (Aerosol Robotic Network) size distribution, it is shown that the model underestimates the coarse mode near mineral dust sources and overestimates the fine mode in the Mediterranean area, highlighting the need to improve the model representation of the aerosol size distribution both during emissions, long-range transport and deposition.

  4. BioAerosol Mass Spectrometry: Reagentless Detection of Individual Airborne Spores and Other Bioagent Particles Based on Laser Desorption/Ionization Mass Spectrometry

    SciTech Connect

    Steele, Paul Thomas

    2004-09-01

    Better devices are needed for the detection of aerosolized biological warfare agents. Advances in the ongoing development of one such device, the BioAerosol Mass Spectrometry (BAMS) system, are described here in detail. The system samples individual, micrometer-sized particles directly from the air and analyzes them in real-time without sample preparation or use of reagents. At the core of the BAMS system is a dual-polarity, single-particle mass spectrometer with a laser based desorption and ionization (DI) system. The mass spectra produced by early proof-of-concept instruments were highly variable and contained limited information to differentiate certain types of similar biological particles. The investigation of this variability and subsequent changes to the DI laser system are described. The modifications have reduced the observed variability and thereby increased the usable information content in the spectra. These improvements would have little value without software to analyze and identify the mass spectra. Important improvements have been made to the algorithms that initially processed and analyzed the data. Single particles can be identified with an impressive level of accuracy, but to obtain significant reductions in the overall false alarm rate of the BAMS instrument, alarm decisions must be made dynamically on the basis of multiple analyzed particles. A statistical model has been developed to make these decisions and the resulting performance of a hypothetical BAMS system is quantitatively predicted. The predictions indicate that a BAMS system, with reasonably attainable characteristics, can operate with a very low false alarm rate (orders of magnitude lower than some currently fielded biodetectors) while still being sensitive to small concentrations of biological particles in a large range of environments. Proof-of-concept instruments, incorporating some of the modifications described here, have already performed well in independent testing.

  5. Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

    NASA Astrophysics Data System (ADS)

    Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

    2009-11-01

    Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used were Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients revealed a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: (1) shielding of inner monomers after particle consolidation or collapse with water uptake; (2) the lower case contribution of mass transfer through evaporation and condensation at high relative humidity (RH) to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

  6. Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

    NASA Astrophysics Data System (ADS)

    Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

    2009-07-01

    Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used are Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients reveal a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: 1. Shielding of inner monomers after particle consolidation or collapse with water uptake; 2. The contribution of mass transfer through evaporation and condensation at high relative humidity to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

  7. Source apportionment of elevated BaP concentrations in PM10 aerosols in an alpine valley in Austria

    NASA Astrophysics Data System (ADS)

    Bauer, Heidi; Puxbaum, Hans; Jankowski, Nicole; Sampaio Cordeiro Wagner, Lylian

    2010-05-01

    INTRODUCTION: In a village situated at 1215 m a.s.l. in a natural preserve in an Austrian alpine valley elevated BaP concentrations have been measured in the last years. A highly frequented highway leading from Italy to Germany passes near the village. Monthly means of particulate BaP concentrations show a clear seasonal trend with values below 1 ng/m³ during the warmer months and with concentrations up to 9 ng/m³ in the cold season. Annual averages in the years 2000 - 2005 ranged between 1.4 and 2.8 ng/m³ - much higher than the EU target value of 1 ng/m³. We used a macrotracer model developed at the Vienna University of Technology to determine the contributions of the sources for BaP emissions, which were mainly space heating with wood and traffic from the highway. EXPERIMENTAL: The macrotracer concept is a nine component model to derive source contribution and explains 80-100% of PM10 aerosols in Austria. The amount of traffic exhaust is derived by using EC as tracer, whereas EC produced by wood burning is subtracted, the amount of wood smoke is derived by the anhydro-sugar levoglucosan and the ratio between the anhydro-sugars levoglucosan and mannosan. For the source apportionment of BaP the applied factors reflect on the one hand the composition of the automotive fleet in Austria and on the other hand the composition of the fire wood in the region. Filter samples collected with a high volume sampler in winter were analyzed for PM10 aerosol mass, total, organic, elemental and carbonate carbon, HULIS, anhydro-sugars, polyols and ions (major ions and organic acids) and PAHs. In the same way emission samples taken at a motor test stand and at a test stand for wood combustion were analyzed (Schmidl et al. 2008). The saccharides were determined using high pH anion exchange and pulsed amperometry (HPAE-PAD). Details of the analytical method are given in Iinuma et al., 2009. Elemental and organic carbon were determined with a thermal-optical instrument (Sunset lab

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

  9. Aerosol characterization over the southeastern United States using high-resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition and sources with a focus on organic nitrates

    NASA Astrophysics Data System (ADS)

    Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

    2015-07-01

    We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particulate matter (NR-PM1) in the southeastern USA. Measurements were performed in both rural and urban sites in the greater Atlanta area, Georgia (GA), and Centreville, Alabama (AL), for approximately 1 year as part of Southeastern Center for Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR-PM1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important, but not dominant, contributions to total OA in urban sites (i.e., 21-38 % of total OA depending on site and season). Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA factor (isoprene-OA) is only deconvolved in warmer months and contributes 18-36 % of total OA. The presence of isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79 %) of OA in all sites. MO-OOA correlates well with ozone in summer but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based

  10. Aqueous-phase photooxidation of levoglucosan - a mechanistic study using Aerosol Time of Flight Chemical Ionization Mass Spectrometry (Aerosol-ToF-CIMS)

    NASA Astrophysics Data System (ADS)

    Zhao, R.; Mungall, E. L.; Lee, A. K. Y.; Aljawhary, D.; Abbatt, J. P. D.

    2014-04-01

    Levoglucosan (LG) is a widely employed tracer for biomass burning (BB). Recent studies have shown that LG can react rapidly with hydroxyl (OH) radicals in the aqueous phase, despite many mass balance receptor models assuming it to be inert during atmospheric transport. In the current study, aqueous-phase photooxidation of LG by OH radicals was performed in the laboratory. The reaction kinetics and products were monitored by Aerosol Time of Flight Chemical Ionization Mass Spectrometry (Aerosol-ToF-CIMS). Approximately 50 reaction products were detected by the Aerosol-ToF-CIMS during the photooxidation experiments, representing one of the most detailed product studies yet performed. By following the evolution of mass defects of product peaks, unique trends of adding oxygen (+O) and removing hydrogen (-2H) were observed among the products detected, providing useful information to determine potential reaction mechanisms and sequences. As well, bond scission reactions take place, leading to reaction intermediates with lower carbon numbers. We introduce a data analysis framework where the average oxidation state (OSc) is plotted against a novel molecular property: double bond equivalence to carbon ratio (DBE / #C). The trajectory of LG photooxidation on this plot suggests formation of poly-carbonyl intermediates and their subsequent conversion to carboxylic acids as a general reaction trend. We also determined the rate constant of LG with OH radicals at room temperature to be 1.08 ± 0.16 × 109 M-1 s-1. By coupling an Aerosol Mass Spectrometer (AMS) to the system, we observed a rapid decay of the mass fraction of organic signals at mass-to-charge ratio 60 (f60), corresponding closely to the LG decay monitored by the Aerosol-ToF-CIMS. The trajectory of LG photooxidation on a f44-f60 correlation plot matched closely to literature field measurement data. This implies that aqueous-phase photooxidation might be partially contributing to aging of BB particles in the ambient

  11. Aqueous-phase photooxidation of levoglucosan - a mechanistic study using aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS)

    NASA Astrophysics Data System (ADS)

    Zhao, R.; Mungall, E. L.; Lee, A. K. Y.; Aljawhary, D.; Abbatt, J. P. D.

    2014-09-01

    Levoglucosan (LG) is a widely employed tracer for biomass burning (BB). Recent studies have shown that LG can react rapidly with hydroxyl (OH) radicals in the aqueous phase despite many mass balance receptor models assuming it to be inert during atmospheric transport. In the current study, aqueous-phase photooxidation of LG by OH radicals was performed in the laboratory. The reaction kinetics and products were monitored by aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS). Approximately 50 reaction products were detected by the Aerosol ToF-CIMS during the photooxidation experiments, representing one of the most detailed product studies yet performed. By following the evolution of mass defects of product peaks, unique trends of adding oxygen (+O) and removing hydrogen (-2H) were observed among the products detected, providing useful information for determining potential reaction mechanisms and sequences. Additionally, bond-scission reactions take place, leading to reaction intermediates with lower carbon numbers. We introduce a data analysis framework where the average oxidation state (OSc) is plotted against a novel molecular property: double-bond-equivalence-to-carbon ratio (DBE/#C). The trajectory of LG photooxidation on this plot suggests formation of polycarbonyl intermediates and their subsequent conversion to carboxylic acids as a general reaction trend. We also determined the rate constant of LG with OH radicals at room temperature to be 1.08 ± 0.16 × 109 M-1 s-1. By coupling an aerosol mass spectrometer (AMS) to the system, we observed a rapid decay of the mass fraction of organic signals at mass-to-charge ratio 60 (f60), corresponding closely to the LG decay monitored by the Aerosol ToF-CIMS. The trajectory of LG photooxidation on a f44-f60 correlation plot matched closely to literature field measurement data. This implies that aqueous-phase photooxidation might be partially contributing to aging of BB particles in the

  12. Single-particle aerosol mass spectrometry for the detection and identification of chemical warfare agent simulants.

    PubMed

    Martin, Audrey N; Farquar, George R; Frank, Matthias; Gard, Eric E; Fergenson, David P

    2007-08-15

    Single-particle aerosol mass spectrometry (SPAMS) was used for the real-time detection of liquid nerve agent simulants. A total of 1000 dual-polarity time-of-flight mass spectra were obtained for micrometer-sized single particles each of dimethyl methyl phosphonate, diethyl ethyl phosphonate, diethyl phosphoramidate, and diethyl phthalate using laser fluences between 0.58 and 7.83 nJ/microm2, and mass spectral variation with laser fluence was studied. The mass spectra obtained allowed identification of single particles of the chemical warfare agent (CWA) simulants at each laser fluence used although lower laser fluences allowed more facile identification. SPAMS is presented as a promising real-time detection system for the presence of CWAs.

  13. Demonstration of a VUV lamp photoionization source for improvedorganic speciation in an aerosol mass spectrometer

    SciTech Connect

    Northway, M.J.; Jayne, J.T.; Toohey, D.W.; Canagaratna, M.R.; Trimborn, A.; Akiyama, K-I.; Shimono, A.; Jimenez, J.L.; DeCarlo, P.F.; Wilson, K.R.; Worsnop, D.R.

    2007-10-03

    In recent years, the Aerodyne AerosolMass Spectrometer(AMS) has become a widely used tool for determining aerosol sizedistributions and chemical composition for non-refractory inorganic andorganic aerosol. The current version of the AMS uses a combination offlash thermal vaporization and 70 eV electron impact (EI) ionization.However, EI causes extensive fragmentation and mass spectra of organicaerosols are difficult to deconvolute because they are composites of theoverlapping fragmentation patterns of all species present. Previous AMSstudies have been limited to classifying organics in broad categoriessuch as oxidized and hydrocarbon-like." In this manuscript we present newefforts to gain more information about organic aerosol composition byemploying the softer technique of vacuum ultraviolet (VUV) ionization ina Time-of-Flight AMS (ToF-AMS). In our novel design a VUV lamp is placedin direct proximity of the ionization region of the AMS, with only awindow separating the lamp and the ionizer. This design allows foralternation of photoionization and electron impact ionization within thesame instrument on the timescale of minutes. Thus, the EI-basedquantification capability of the AMS is retained while improved spectralinterpretation is made possible by combined analysis of the complementaryVUV and EI ionization spectra. Photoionization and electron impactionization spectra are compared for a number of compounds including oleicacid, long chain hydrocarbons, and cigarette smoke. In general, the VUVspectra contain much less fragmentation than the EI spectra and for manycompounds the parent ion is the dominant ion in the VUV spectrum. As anexample of the usefulness of the integration of PI within the fullcapability of the ToF-AMS, size distributions and size-segregated massspectra are examined for the cigarette smoke analysis. As a finalevaluation of the new VUV module, spectra for oleic acid are compared tosimilar experiments conducted using the tunable VUV radiation

  14. Aerosol size distribution and aerosol water content measurements during Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Sievering, H.; Boatman, J.; Wellman, D.; Pszenny, A.

    1995-11-01

    Aerosol size distribution data measured during the June 1992 Marine Aerosol and Gas Exchange experiment are analyzed to investigate the characteristics of fine marine aerosol particles measured over the North Atlantic near the Azores Islands. Measured aerosol size distribution data were corrected using the corrected size calibration data based on the optical properties of particles being measured. The corrected size distribution data were then approximated with either one or two lognormal size distributions, depending on air mass conditions. Under clean air mass conditions <3 μm diameter aerosol size distributions typically exhibited two modes, consisting of an accumulation mode and the small end of the sea-salt particle mode. However, under the influence of continental polluted air masses, the aerosol size distribution was dominated by <1 μm diameter particles in a single mode with an increased aerosol concentration. Aerosol water content of accumulation mode marine aerosols was estimated from differences between several series of ambient and dried aerosol size distributions. The average aerosol water fraction was 0.31, which is in good agreement with an empirical aerosol growth model estimate. The average rate of SO4= production in the accumulation mode aerosol water by H2O2 oxidation was estimated to be <7×10-10 mol L-1 s-1, which is an insignificant contributor to the observed non-sea-salt SO4= in the accumulation mode.

  15. Relationship between column aerosol optical properties and surface aerosol gravimetric concentrations during the Distributed Regional Aerosol Gridded Observation Network - Northeast ASIA 2012 campaign

    NASA Astrophysics Data System (ADS)

    Jeong, U.; Kim, J.; Seo, S.; Choi, M.; Kim, W. V.; Holben, B. N.; Lee, S.; Kim, J.

    2012-12-01

    One of the main objectives of Distributed Regional Aerosol Gridded Observation Network (DRAGON) campaign in Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) mission is to understand the relationship between the column optical properties of the atmosphere and the surface level air quality in terms of aerosols and gases. This study aims to identify the important parameters that affecting the relationship between those variables during the DRAGON - northeast Asia 2012 campaign. Column aerosol optical properties from ten Cimel sun photometers at DRAGON sites in Seoul, MODIS (Moderate Resolution Imaging Spectroradiometer), and GOCI (Geostationary Ocean Color Imager) and particulate matter (PM10) sampling from 40 NIER (National Institute of Environmental Research of South Korea) measurement sites in Seoul during the period of 1st March - 31th May 2012 were employed in this study. The key parameters in relationship between aerosol optical depth (AOD) and PM are reported to be aerosol vertical profile and hygroscopicity of the aerosols. The meteorological conditions including relative humidity, surface temperature, and wind speed that could affect those parameters were investigated.

  16. Indoor/outdoor radon decay products associated aerosol particle-size distributions and their relation to total number concentrations.

    PubMed

    Moriizumi, Jun; Yamada, Shinya; Xu, Yang; Matsuki, Satoru; Hirao, Shigekazu; Yamazawa, Hiromi

    2014-07-01

    The activity size distributions of indoor and outdoor radioactive aerosol associated with short-lived radon decay products were observed at Nagoya, Japan, for some periods from 2010 to 2012, following the indoor observation by Mostafa et al. [Mostafa, A. M. A., Tamaki, K., Moriizumi, J., Yamazawa, H. and Iida, T. The weather dependence of particle size distribution of indoor radioactive aerosol associated with radon decay products. Radiat. Prot. Dosim. 146: (1-3), 19-22 (2011)]. The tendency of smaller indoor activity median aerodynamic diameter (AMAD) after rainfalls showed in the previous study was not consistently obtained, while the consistent tendency of less indoor radioactive particles with diameters in the accumulation mode was observed again after rainfalls. The indoor aerosols showed activity size distributions similar to the outdoor ones. Non-radioactive aerosol particle concentrations measured with a laser particle counter suggested a somewhat liner relationship with AMAD.

  17. Multiday production of condensing organic aerosol mass in urban and forest outflow

    DOE PAGES

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; ...

    2015-01-16

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for multiple days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (~50%) and of shorter duration (1–2 days). The multiday production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction productsmore » of both aromatics and alkanes, especially those with relatively low carbon numbers (C4–15). In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions and different vapor pressure schemes, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.« less

  18. Multiday production of condensing organic aerosol mass in urban and forest outflow

    DOE PAGES

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; ...

    2014-07-03

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for several days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (∼50%) and of shorter duration (1–2 days). The production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products ofmore » both aromatics and alkanes. In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.« less

  19. Multiday production of condensing organic aerosol mass in urban and forest outflow

    NASA Astrophysics Data System (ADS)

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2014-07-01

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for several days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (∼50%) and of shorter duration (1-2 days). The production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products of both aromatics and alkanes. In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.

  20. Multiday production of condensing organic aerosol mass in urban and forest outflow

    NASA Astrophysics Data System (ADS)

    Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.; Camredon, M.; Valorso, R.

    2015-01-01

    Secondary organic aerosol (SOA) production in air masses containing either anthropogenic or biogenic (terpene-dominated) emissions is investigated using the explicit gas-phase chemical mechanism generator GECKO-A. Simulations show several-fold increases in SOA mass continuing for multiple days in the urban outflow, even as the initial air parcel is diluted into the regional atmosphere. The SOA mass increase in the forest outflow is more modest (~50%) and of shorter duration (1-2 days). The multiday production in the urban outflow stems from continuing oxidation of gas-phase precursors which persist in equilibrium with the particle phase, and can be attributed to multigenerational reaction products of both aromatics and alkanes, especially those with relatively low carbon numbers (C4-15). In particular we find large contributions from substituted maleic anhydrides and multi-substituted peroxide-bicyclic alkenes. The results show that the predicted production is a robust feature of our model even under changing atmospheric conditions and different vapor pressure schemes, and contradict the notion that SOA undergoes little mass production beyond a short initial formation period. The results imply that anthropogenic aerosol precursors could influence the chemical and radiative characteristics of the atmosphere over an extremely wide region, and that SOA measurements near precursor sources may routinely underestimate this influence.

  1. Air mass modification over Europe: EARLINET aerosol observations from Wales to Belarus

    NASA Astrophysics Data System (ADS)

    Wandinger, Ulla; Mattis, Ina; Tesche, Matthias; Ansmann, Albert; BöSenberg, Jens; Chaikovski, Anatoly; Freudenthaler, Volker; Komguem, Leonce; Linné, Holger; Matthias, Volker; Pelon, Jacques; Sauvage, Laurent; Sobolewski, Piotr; Vaughan, Geraint; Wiegner, Matthias

    2004-12-01

    For the first time, the vertically resolved aerosol optical properties of western and central/eastern European haze are investigated as a function of air mass transport. Special emphasis is put on clean maritime air masses that cross the European continent from the west and become increasingly polluted on their way into the continent. The study is based on observations at seven lidar stations (Aberystwyth, Paris, Hamburg, Munich, Leipzig, Belsk, and Minsk) of the European Aerosol Research Lidar Network (EARLINET) and on backward trajectory analysis. For the first time, a lidar network monitored continent-scale haze air masses for several years (since 2000). Height profiles of the particle backscatter coefficient and the particle optical depth of the planetary boundary layer (PBL) at 355-nm wavelength are analyzed for the period from May 2000 to November 2002. From the observations at Aberystwyth, Wales, the aerosol reference profile for air entering Europe from pristine environments was determined. A mean 355-nm optical depth of 0.05 and a mean PBL height of 1.5 km was found for clean maritime summer conditions. The particle optical depth and PBL height increased with increasing distance from the North Atlantic. Mean summer PBL heights were 1.9-2.8 km at the continental sites of Leipzig, Belsk, and Minsk. Winter mean PBL heights were mostly between 0.7 and 1.3 km over the seven EARLINET sites. Summer mean 355-nm optical depths increased from 0.17 (Hamburg, northwesterly airflow from the North Sea) and 0.21 (Paris, westerly flow from the Atlantic) over 0.33 (Hamburg, westerly flow) and 0.35 (Leipzig, westerly flow) to 0.59 (Belsk, westerly flow), and decreased again to 0.37 (westerly flow) at Minsk. Winter mean optical depths were, on average, 10-30% lower than the respective summer values. PBL-mean extinction coefficients were of the order of 200 Mm-1 at 355 nm at Hamburg and Leipzig, Germany, and close to 600 Mm-1 at Belsk, Poland, in winter for westerly flows

  2. [Characteristics of mass distributions of aerosol particle and its inorganic water-soluble ions in summer over a suburb farmland in Beijing].

    PubMed

    Zhao, Peng; Zhu, Tong; Liang, Bao-sheng; Hu, Min; Kang, Ling; Gong, Ji-cheng

    2006-02-01

    Agricultural activity is one of the important sources of aerosol particle. To understand the mass distribution and sources of aerosol particle and its inorganic water-soluble ions in the suburb farmland of Beijing, particle samples were collected with a MOUDI cascade impactor in the summer of 2004 in a suburb vegetable field. The mass distributions of the particle and its inorganic water-soluble ions in the diameter range of 0.18 to approximately 18 microm were measured. The dominant ions in the fine particle were SO4(2-), NOS3(-) and NH4+. The association of day to day variation of the concentration of these ions with temperature, humidity and solar radiation suggests that they are formed by the reaction of NH3 released from the vegetable field with the acid species produced from photochemical reactions. K+ in the fine particle is likely from the vegetation emission and biomass burning. Ca2+, Mg2+, NO3(-) and SO4(2-) in the coarse particle are suggested to come from the mechanical process by which the soil particle entered the atmosphere, and from the reactions of the acid species at the surface of the soil particle. The results show that fertilizer and soil are possibly important factors determining the aerosol particle over the agricultural fields, and the vegetable fields in suburb Beijing could contribute significantly to the aerosol particle.

  3. An Investigation of Size-Dependent Concentration of Trace Elements in Aerosols Emitted from the Oil-Fired Heating Plants

    NASA Technical Reports Server (NTRS)

    Singh, J. J.; Sentell, R. J.; Khandelwal, G. S.

    1976-01-01

    Aerosols emitted from two oil-fired heating plants were aerodynamically separated into eight size groups and were analyzed using the photon-induced X-ray emission (PIXE) technique. It was found that Zn, Mo, Ag, and Pb, and (to a lesser extent) Cd, have a tendency to concentrate preferentially on the smaller aerosols. All of these elements, in certain chemical forms, are known to be toxic. Zinc and molybdenum, although present in low concentrations in the parent fuels, show the strongest tendencies to be concentrated in finer aerosols. Selenium, previously reported to show a very strong tendency to concentration in finer fly ash from coal-fired power plants shows little preference for surface residence. Vanadium, which occurs in significant concentration in the oil fuels for both plants, also shows little preference for surface concentration. Even though the absolute concentrations of the toxic elements involved are well below the safety levels established by the National Institute for Occupational Safety and Health (NIOSH), it would be advisable to raise the heights of the heating-plant exhaust chimneys well above the neighborhood buildings to insure more efficient aerosol dispersal.

  4. Light Absorption in the Stratosphere: Trend, Soot Aerosol Concentration and Contribution by...

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Verma, S.; Strwwa, A. W.; Ferry, G. V.; Hamill, P.; Vay, S.; Gore, Warren J. Y. (Technical Monitor)

    1997-01-01

    The light absorption coefficient, Beta(a) of the stratospheric aerosol is an important quantity that determines its radiative effects. When combined with the aerosol scattering coefficient, Beta(a) it becomes possible to evaluate the aerosol single scatter albedo, omega = Beta(s)/(Beta(s) + Beta(a)) which is essential for modeling the overall radiative effects of the stratospheric aerosol. Pollack1 determined that omega = 0.98 is a critical value that separates stratospheric cooling from warming.

  5. SO2 photolysis as a source for sulfur mass-independent isotope signatures in stratospehric aerosols

    NASA Astrophysics Data System (ADS)

    Whitehill, A. R.; Jiang, B.; Guo, H.; Ono, S.

    2015-02-01

    Signatures of sulfur isotope mass-independent fractionation (S-MIF) have been observed in stratospheric sulfate aerosols deposited in polar ice. The S-MIF signatures are thought to be associated with stratospheric photochemistry following stratospheric volcanic eruptions, but the exact mechanism responsible for the production and preservation of these signatures is debated. In order to identify the origin and the mechanism of preservation for these signatures, a series of laboratory photochemical experiments were carried out to investigate the effect of temperature and added O2 on the S-MIF produced by two absorption band systems of SO2: photolysis in the 190 to 220 nm region and photoexcitation in the 250 to 350 nm region. The SO2 photolysis (SO2 + hν → SO + O) experiments showed S-MIF signals with large 34S/34S fractionations, which increases with decreasing temperature. The overall S-MIF pattern observed for photolysis experiments, including high 34S/34S fractionations, positive mass-independent anomalies in 33S, and negative anomalies in 36S, is consistent with a major contribution from optical isotopologue screening effects and data for stratospheric sulfate aerosols. In contrast, SO2 photoexcitation produced products with positive S-MIF anomalies in both 33S and 36S, which is different from stratospheric sulfate aerosols. SO2 photolysis in the presence of O2 produced SO3 with S-MIF signals, suggesting the transfer of the S-MIF anomalies from SO to SO3 by the SO + O2 + M → SO3 + M reaction. This is supported with energy calculations of stationary points on the SO3 potential energy surfaces, which indicate that this reaction occurs slowly on a single adiabatic surface, but that it can occur more rapidly through intersystem crossing. Based on our experimental results, we estimate a termolecular rate constant on the order of 10-37 cm6 molecule-2 s-1. This rate can explain the preservation of mass independent isotope signatures in stratospheric sulfate

  6. Ambient aerosol chlorine concentrations and artefacts during the MEGAPOLI Paris campaigns

    NASA Astrophysics Data System (ADS)

    Furger, Markus; Visser, Suzanne; Slowik, Jay; Crippa, Monica; Poulain, Laurent; Sciare, Jean; Flechsig, Uwe; Prévôt, André; Baltensperger, Urs

    2015-04-01

    Trace elements, especially those that are toxic, can affect the environment in significant ways. Studying them is advantageous with respect to a refinement of source apportionment when measured with high time resolution and appropriate size segregation. This approach is especially useful in urban environments with numerous time-variant emission sources distributed across a relatively narrow space. Two field campaigns took place in the framework of the MEGAPOLI project in Paris, France: one in the summer of 2009 (1-31 July), the other in the winter of 2010 (11 Jan - 10 Feb). Rotating drum impactors (RDI) were operated at an urban and a suburban site in each campaign. The RDI segregated the aerosols into three size ranges (PM10-2.5, PM2.5-1.0 and PM1.0-0.3) and sampled with 2-hour time resolution. The samples were analyzed with synchrotron radiation-induced X-ray fluorescence spectrometry (SR-XRF) at the synchrotron facility of the Paul Scherrer Institute (SLS), where a broad range of elements (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn) was analyzed for each size range. Time series of the analyzed elements for the different sites and campaigns were prepared to characterize the aerosol trace element composition and temporal behavior for different weather situations and urban environments. Quality assurance was performed partly by intercomparison with independent measurements. An exceptional behavior was observed for chlorine (Cl), where periods with zero RDI concentration alternated with periods of normal load. Zero concentrations were not observed in particle-into-liquid (PILS) measurements. This identifies the observed behavior as a RDI sampling artefact. Nevertheless, the non-zero periods of Cl concentrations are still a gain in information compared to conventional sampling techniques, mainly due to the high time resolution.

  7. Mass-mobility characterization of flame-made ZrO2 aerosols: primary particle diameter and extent of aggregation.

    PubMed

    Eggersdorfer, M L; Gröhn, A J; Sorensen, C M; McMurry, P H; Pratsinis, S E

    2012-12-01

    Gas-borne nanoparticles undergoing coagulation and sintering form irregular or fractal-like structures affecting their transport, light scattering, effective surface area, and density. Here, zirconia (ZrO(2)) nanoparticles are generated by scalable spray combustion, and their mobility diameter and mass are obtained nearly in situ by differential mobility analyzer (DMA) and aerosol particle mass (APM) measurements. Using these data, the density of ZrO(2) and a power law between mobility and primary particle diameters, the structure of fractal-like particles is determined (mass-mobility exponent, prefactor and average number, and surface area mean diameter of primary particles, d(va)). The d(va) determined by DMA-APM measurements and this power law is in good agreement with the d(va) obtained by ex situ nitrogen adsorption and microscopic analysis. Using this combination of measurements and above power law, the effect of flame spray process parameters (e.g., precursor solution and oxygen flow rate as well as zirconium concentration) on fractal-like particle structure characteristics is investigated in detail. This reveals that predominantly agglomerates (physically-bonded particles) and aggregates (chemically- or sinter-bonded particles) of nanoparticles are formed at low and high particle concentrations, respectively.

  8. On the submicron aerosol distributions and CCN number concentrations in and around the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Yum, S. S.; Shim, S.; Kim, W. J.; Park, M.; Kim, J.-H.; Kim, M.-H.; Yoon, S.-C.

    2014-08-01

    Total number concentrations of particles having a diameter larger than 10 nm (NCN), cloud condensation nuclei at several supersaturation (S) values (NCCN) and number size distributions of particles with 10-414 nm diameter were measured in Seoul between 2004 and 2010. Overall average values of NCN and geometric mean diameter were 17 811 ± 5581 cm-3 and 48 ± 6 nm. Average NCCN at 0.4, 0.6 and 0.8% S were 4145 ± 2016, 5323 ± 2453 and 6067 ± 2780 cm-3 and corresponding NCCN / NCN were 0.26 ± 0.11, 0.33 ± 0.11 and 0.37 ± 0.12. There is a clear seasonal variation in aerosol concentration, which seems to be due to the monsoon. NCN and NCCN are also found to depend on the volume of traffic and the height of the planetary boundary layer, respectively. During aircraft campaigns in 2009 and 2011, NCN and NCCN at 0.6% S (N0.6%) were measured in and around the Korean Peninsula. During the 2011 campaign, the aerosol scattering coefficient was also measured. NCN and N0.6% in the lower altitudes were generally higher than at higher altitudes, except for cases when particle formation and growth events were thought to occur at h