Abstract
Organic material accounts for a large fraction of atmospheric aerosol, with the majority being secondary organic aerosol (SOA) formed through oxidation processes. Primary emissions leading to SOA include thousands of chemicals from a variety of natural and anthropogenic sources ranging over approximately 15 orders of magnitude of volatility. As organics are oxidized they fragment to form smaller volatiles or add functionality leading to SOA formation, dramatically increasing the complexity of compounds present. A continuing challenge in aerosol research is to elucidate the sources, structure, chemistry, fate, climate and health impacts of these organic atmospheric constituents.
The complex chemical composition of organic aerosols presents unique measurement challenges. The speaker’s group and close collaborators have developed the Thermal Desorption Aerosol Gas chromatograph (TAG) system for hourly in-situ speciation of a wide range of primary and secondary organic compounds in aerosols. This instrument combines a particle collector with thermal desorption followed by GCMS detection to provide hourly separation, identification, and quantification of organic constituents at the molecular level. The speaker and his group incorporated two-dimensional chromatography (GCxGC), providing dramatically enhanced speciation and developed a semivolatile collection and analysis system that allows simultaneous measurement of specific organics in the gas and particle phases, enabling analysis of their partitioning. They also developed a combined TAG-AMS (Aerosol Mass Spectrometer) instrument for simultaneous measurements of the total and speciated aerosol composition. They are also exploiting soft ionization with vacuum ultraviolet radiation using a high resolution time of flight mass spectrometer (GCxGC/VUV-HRTOFMS) to more fully separate and identify compounds in complex mixtures such as diesel fuel, motor oil, vehicle emissions, fire emissions, in controlled oxidation studies, and in ambient samples. In this lecture, the speaker will review recent developments (TAG, 2DTAG, SVTAG, TAG-AMS, GCxGC/VUV-HRTOFMS), and present new atmospheric observations, source characterizations, and controlled oxidation studies to more fully characterize atmospheric organic sources and transformation processes.
About the speaker
Prof Allen Goldstein received his MS and PhD in Chemistry from Harvard University in 1991 and 1994 respectively. He joined the University of California at Berkeley in 1994 and is currently the Professor of Environmental Science, Policy and Management and also the Professor of Civil and Environmental Engineering.
Prof Goldstein’s research focuses on the interactions between atmospheric chemistry and terrestrial biogeochemistry, and how these interactions influence biosphere-atmosphere exchange and determine atmospheric composition. He and his group investigate anthropogenic and natural contributions to the chemical composition of the troposphere, interactions of air pollution with ecosystems, aerosol composition and chemistry, and the biogeochemistry of greenhouse gases and stratospheric ozone depleting gases.
Prof Goldstein received numerous of awards including the Senator Harry E. Drobish Award for Innovative Education Activities, the Norbert Gerbier-MUMM International Award and the Camile and Henry Dreyfus Environmental Chemistry Mentor Award. He was also elected the Follow of the American Geophysical Union and AEESP Plenary Lecturer by the American Association for Aerosol Research.
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