AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Incremental Secondary Organic Aerosol Formation and Composition at Simulated Urban Atmospheric Reactivities
MARY KACARAB, Lijie Li, William P. L. Carter, David R. Cocker III, University of California, Riverside
Abstract Number: 361 Working Group: Urban Aerosols
Abstract Two surrogate reactive organic gas (ROG) atmospheric mixtures of anthropogenic and biogenic volatile organic compounds (VOCs) were developed to represent simulated urban atmospheres with different levels of anthropogenic and biogenic influences (i.e. Los Angeles reactivity versus Atlanta reactivity). Previous chamber studies have focused on the oxidation of single aerosol precursors, which may not provide an accurate representation of aerosol yield in different urban environments. The incremental aerosol yields from select anthropogenic (aromatic) and biogenic (terpene) hydrocarbon precursors were studied in the UC Riverside/CE-CERT dual 90m$^3 environmental chambers under these two simulated urban conditions. It was found that the aerosol precursors behaved differently under the two differing reactivity conditions, with more incremental aerosol being formed in the anthropogenically dominated mixture than in the biogenically dominated mixture. Further, the biogenic reactivity condition inhibited the oxidation of added anthropogenic aerosol precursors, such as m-xylene. Aerosol properties such as density, volatility, and bulk chemical composition (from Aerodyne high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS)) data will be presented and compared between the two reactivity systems and with data from previous single VOC/NOx photo-oxidation studies. Data from incremental aerosol yield experiments at different atmospheric reactivities are paramount in the attempt to extrapolate environmental chamber observations to the ambient atmospheric measurements.