Grantee Research Project Results
2005 Progress Report: Fundamental Experimental and Modeling Studies of Secondary Organic Aerosol
EPA Grant Number: R831075Title: Fundamental Experimental and Modeling Studies of Secondary Organic Aerosol
Investigators: Seinfeld, John
Institution: California Institute of Technology
EPA Project Officer: Chung, Serena
Project Period: July 1, 2003 through June 30, 2006
Project Period Covered by this Report: July 1, 2004 through June 30, 2005
Project Amount: $449,991
RFA: Measurement, Modeling, and Analysis Methods for Airborne Carbonaceous Fine Particulate Matter (PM2.5) (2003) RFA Text | Recipients Lists
Research Category: Particulate Matter , Air Quality and Air Toxics , Air
Objective:
The objective of this research project is to understand the sources, molecular composition, and chemistry of the formation of atmospheric secondary organic aerosol (SOA), which represents a key problem in atmospheric chemistry.
Progress Summary:
A significant fraction of atmospheric organic aerosols is formed through in-situ oxidation of precursor hydrocarbons followed by partitioning of low-volatility products into the aerosol phase. This component of atmospheric organic aerosols is referred to as SOA. Understanding the mechanisms of formation of SOA represents an outstanding problem. Recent discoveries have indicated that full understanding of the molecular mechanisms of SOA formation is lacking. A number of laboratory studies, including the present work, have identified polymeric species as potentially major components in secondary organic aerosols from the ozonolysis of a-pinene, isoprene, and a number of cycloalkenes. It has been proposed that these polymers are formed in the aerosol phase through heterogeneous reactions involving oxidation products with low molecular weight (below 200 Da). In light of these results, it becomes crucial to understand heterogeneous reactions that occur and the effect of such reactions on formation of SOA. Another factor that is emerging as crucial in SOA formation is the NOx level. We are carrying out a comprehensive study of SOA formation from key biogenic and anthropogenic precursor hydrocarbons, spanning a range of particle acidity, temperature, and relative humidity. In the upcoming period, we also will be evaluating thermodynamic models of inorganic/organic/water aerosols.
Future Activities:
Because of the enormous importance of isoprene as a source of ambient SOA, we are continuing to devote major effort to determining the detailed mechanism of atmospheric SOA format from isoprene, especially the role of NOx and of particle acidity. Our goal is to produce a comprehensive set of data on SOA formation from isoprene that may be parameterized for models, such as the Community Multi-scale Air Quality Model.
Journal Articles on this Report : 8 Displayed | Download in RIS Format
| Other project views: | All 24 publications | 24 publications in selected types | All 24 journal articles |
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Bahreini R, Keywood MD, Ng NL, Varutbangkul V, Gao S, Flagan RC, Seinfeld JH, Worsnop DR, Jimenez JL. Measurements of secondary organic aerosol from oxidation of cycloalkenes, terpenes, and m-xylene using an Aerodyne aerosol mass spectrometer. Environmental Science & Technology 2005;39(15):5674-5688. |
R831075 (2005) R831075 (Final) |
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Gao S, Ng NL, Keywood M, Varutbangkul V, Bahreini R, Nenes A, He J, Yoo KY, Beauchamp JL, Hodyss RP, Flagan RC, Seinfeld JH. Particle phase acidity and oligomer formation in secondary organic aerosol. Environmental Science & Technology 2004;38(24):6582-6589. |
R831075 (2004) R831075 (2005) R831075 (Final) |
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Gao S, Keywood M, Ng NL, Surratt J, Varutbangkul V, Bahreini R, Flagan RC, Seinfeld JH. Low-molecular-weight and oligomeric components in secondary organic aerosol from the ozonolysis of cycloalkenes and α-pinene. The Journal of Physical Chemistry A 2004;108(46):10147-10164. |
R831075 (2004) R831075 (2005) R831075 (Final) |
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Kroll JH, Ng NL, Murphy SM, Varutbangkul V, Flagan RC, Seinfeld JH. Chamber studies of secondary organic aerosol growth by reactive uptake of simple carbonyl compounds. Journal of Geophysical Research-Atmospheres 2005;110(D23):D23207 (10 pp.). |
R831075 (2005) R831075 (Final) |
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Kroll JH, Seinfeld JH. Representation of secondary organic aerosol laboratory chamber data for the interpretation of mechanisms of particle growth. Environmental Science & Technology 2005;39(11):4159-4165. |
R831075 (2005) R831075 (Final) |
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Kroll JH, Ng NL, Murphy SM, Flagan RC, Seinfeld JH. Secondary organic aerosol formation from isoprene photooxidation under high-NOx conditions. Geophysical Research Letters 2005;32(18):L18808 (4 pp.). |
R831075 (2005) R831075 (Final) |
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Lee A, Goldstein AH, Keywood MD, Gao S, Varutbangkul V, Bahreini R, Ng NL, Flagan RC, Seinfeld JH. Gas-phase products and secondary aerosol yields from the ozonolysis of ten different terpenes. Journal of Geophysical Research--Atmospheres 2006;111(D7):D07302 (18 pp.). |
R831075 (2005) R831075 (Final) |
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VanReken TM, Ng NL, Flagan RC, Seinfeld JH. Cloud condensation nucleus activation properties of biogenic secondary organic aerosol. Journal of Geophysical Research-Atmospheres 2005;110(D7):D07206 (9 pp.). |
R831075 (2005) R831075 (Final) |
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Supplemental Keywords:
troposphere, health effects, environmental chemistry, analytical,, RFA, Air, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, POLLUTANTS/TOXICS, particulate matter, Environmental Chemistry, Monitoring/Modeling, Air Pollution Effects, air toxics, Chemicals, Environmental Engineering, Environmental Monitoring, aerosol particles, health effects, atmospheric dispersion models, secondary organic aerosol, air sampling, carbon particles, emissions, monitoring stations, measurement methods, modeling studies, secondary organic aerosols, particulate matter mass, air quality model, analysis of organic particulate matter, aerosol analyzers, air quality models, atmospheric particulate matter, particle phase molecular markers, transport modeling, Volatile Organic Compounds (VOCs), human health effects, atmospheric measurements, modelingProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.