AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Characterization of Organic Aerosol from Mixed Biogenic / Anthropogenic Emissions
DHRUV MITROO, Brent Williams, Raul Martinez, Yaping Zhang, William Brune, Munkhbayar Baasandorj, Lu Hu, Dylan Millet, Washington University in St. Louis
Abstract Number: 400 Working Group: Aerosol Chemistry
Abstract Chemical reaction mechanisms have been studied in detail for single component or simple mixtures of volatile biogenic (e.g., isoprene, a-pinene) and anthropogenic (e.g., xylene) aerosol precursor gases. Recent studies to determine secondary aerosol yields from the oxidation of these volatile species under variable conditions (e.g., over a range of VOC concentrations, NOx concentrations, and RH values) have been performed in controlled laboratory settings using static smog chambers and flow-tube steady state reactors. It has been observed in the field and shown through these laboratory studies that secondary organic aerosol (SOA) yields can be increased with a mixture of biogenic and anthropogenic emissions. The details of the controlling chemical mechanisms remain highly uncertain, leaving current models unable to accurately predict aerosol concentrations in regions with mixed emission sources.
Here, we present preliminary data from controlled laboratory experiments to offer insight on active chemical pathways that may be controlling enhanced SOA formation in the atmosphere. We use a custom-built emission chamber for complex source emissions coupled with the Potential Aerosol Mass (PAM) reactor, a flow tube reactor, to mimic atmospheric oxidation, and finally, a variety of mass spectral detection techniques to determine organic gas and particle composition before and after various degrees of mimicked atmospheric aging.