AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Significant Organic Aerosol Formation from Biogenic Volatile Organic Compounds in the Southeastern United States
LU XU, Havala Pye, Jia He, Yunle Chen, Benjamin Murphy, Nga Lee Ng, California Institute of Technology
Abstract Number: 375 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Organic aerosol (OA), which constitutes a substantial fraction of fine particulate matter (PM), has large impacts on air quality, climate change, and human health. However, due to complex sources and formation mechanisms of OA, the contributions from different sources to OA are highly uncertain. Positive matrix factorization (PMF) analysis on the organic mass spectra obtained by the high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is a widely used method for OA source apportionment. However, it is largely unknown regarding what sources/processes contribute to OA factors, especially the more-oxidized oxygenated OA (MO-OOA) and less-oxidized oxygenated OA (LO-OOA). In this study, we apply novel experimental protocol and show that LO-OOA is related to fresh SOA from the oxidation of biogenic volatile organic compounds (VOCs) in the southeastern United States. To simulate the SOA formation in the southeastern U.S., we use Community Multiscale Air Quality model (CMAQ) with latest laboratory findings implemented. The model results agree well with measured SOA from biogenic VOCs at multiple sites in the southeastern U.S. Our novel experimental approach also provides substantial insights in understanding the sources of other OA factors.