Seinfeld 9307603 Gas-to-particle conversion is a ubiquitous process in the atmosphere, understanding the detailed chemistry and physics of which will allow one to predict the effects of primary gaseous and particulate emissions on airborne particulate matter composition and size. This comprehensive research program determine the mechanisms of secondary organic aerosols formation in the atmosphere for a number of important anthropogenic and biogenic hydrocarbons. Experiments in a 1000 liter indoor reactor will be used to probe gas-phase photooxidation mechanisms. A 4 m3 outdoor smog chamber will be used to generate organic aerosols for molecular speciation analysis by gas chromatography/mass spectrometry, while the 60 m3 outdoor smog chamber will be employed to study the integrated gas-phased and gas-to-particle conversion dynamics. Vapor pressures of individual secondary organic aerosol constituents and of the aerosol generated by hydrocarbon photooxidation will be determined with the tandem differential mobility analyzer (TDMA). Information from the individual experiments studies will be integrated in the data analysis phase. Gas-phase photooxidation mechanisms will be formulated and aerosol physics models will be developed based on the concentration dynamics, molecular speciation, and the physical properties deduced from the TDMA studies.
