ARB Research Seminar
This page updated June 19, 2013
Hourly, In-Situ Quantification of Organic Aerosol Marker Compounds
Allen H. Goldstein, Ph.D., Chairman, Department of Environmental Science, Policy, and Management, University of California, Berkeley
July 01, 2008
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA
Regulatory efforts to attain fine particulate matter (PM2.5) standards require improvements in our knowledge of the factors controlling the concentration, size, and chemical composition of PM2.5. While many advances have been made in measuring and modeling the inorganic ionic species that are found in PM2.5, much less is known about the organic fraction. Yet organic matter is a major constituent of airborne particles, comprising 20-80% of the PM2.5 mass in many regions. Quantitative knowledge of the composition of PM2.5 organic matter is a key to understanding its sources, formation, and transformation processes.
Professor Goldstein and his team developed an automated in-situ Thermal Desorption Aerosol GC (TAG) system and successfully used it to create the first ever measurements of speciated organic aerosol on an hourly basis. The sampling and data acquisition process were fully automated, allowing around-the-clock operation, free of artifacts associated with filter collection and handling. Measurements were made as part of the Study on Oxidants and Aerosols in Riverside (SOAR) during one month in summer and one month in Fall 2005. The high time resolution obtained by TAG measurements allowed observations of diurnal changes in aerosol organic composition and were related to diurnal changes in sources. For the first time, it was observed that SOA contributes in average 75% of the organic aerosol mass during summertime afternoons in this region downwind of Los Angeles. The variation in organic composition in each study period, along with other data, was used to identify the relative contributions of local vehicles, regional anthropogenic particulate emissions, biomass burning, biogenic sources, and secondary organic matter.
Allen H. Goldstein, Ph.D., is a Professor of Biogeochemistry and Chair of the Department of Environmental Science, Policy, and Management, at the University of California, Berkeley. Dr. Goldstein is also a core member of the Berkeley Atmospheric Sciences Center and a faculty Chemist at Lawrence Berkeley National Laboratory. Professor Goldstein's research focuses on the interface between natural and anthropogenic influences on regional photochemistry, including formation of ozone and aerosols. A major focus of his research has been the development of novel analytical approaches for observing organic compounds in earth's atmosphere.