Grantee Research Project Results
Characterization of Highly Oxygenated Organic Compounds and Organosulfates in Atmospheric Particulate MatterEPA Grant Number: FP917189
Title: Characterization of Highly Oxygenated Organic Compounds and Organosulfates in Atmospheric Particulate Matter
Investigators: Isaacman, Gabriel A.
Institution: University of California - Berkeley
EPA Project Officer: Just, Theodore J.
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010)
Research Category: Academic Fellowships , Fellowship - Clean Air
This project aims to expand the ability to characterize both highly oxygenated and sulfur-containing atmospheric oxidation products of prevalent volatile organic compounds. It also will attempt to quantify the extent to which interaction between anthropogenic and biogenic emissions to the atmosphere leads to formation of secondary aerosol in regions like the southeastern United States, where emissions from both sources are high.
Specific compounds in atmospheric particulate matter (“smog”) can be used to understand its sources and formation. This project will study the variability over the course of the day of such “marker compounds” using a custom instrument that has a better time resolution than typical techniques. The applicant proposes to expand current capabilities of this instrument to include the detection of compounds found in more aged air, which make up a significant fraction of all particulate matter.Approach:
The composition of organic atmospheric aerosol has been characterized to date primarily through the use of filter collection and analysis. However, this approach does not provide an understanding of diurnal variability of individual compounds, which can be used to understand sources and formation processes. Therefore, this project will seek to improve a recently designed custom instrument, the Thermal Desorption Aerosol Gas Chromatograph (TAG). The range of compounds detectable by TAG will be expanded to include markers of oxidized and aged air through the use of “derivatization,” where a chemical reaction will be employed to change the structure of analyzed air in such a way to allow detection. The exact reaction is not yet known and will require significant experimentation. Following development of these methods, the instrument will be deployed to the field to understand the sources of particulate matter in polluted and/or non-polluted areas.Expected Results:
Highly oxygenated compounds are known to be a significant fraction of atmospheric aerosol but cannot be easily characterized with high time resolution using current methods. This work will address this issue, providing better knowledge about the diurnal variability of these compounds. Such knowledge can and will be used for source apportionment as well as studies into the products of known precursor gas-phase compounds. This work will better constrain the causes of some air pollution, specifically small particulate matter (PM2.5), one of EPA’s six “criteria pollutants.”
Potential to Further Environmental/Human Health Protection:
Atmospheric aerosol affects human health and climate, and these effects vary based on the composition of the aerosol. This research seeks to understand the composition of aerosol, thus understanding its effects. Furthermore, by having high time resolution in these measurements, the sources and formation processes can be better understood, assisting in future mitigation efforts.Supplemental Keywords:
air pollution, aerosol, particulate matter, PM2.5, criteria pollutants, derivatization, volatile organic compounds,