AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Organic Aerosol Sources Determined by Molecular Markers Observed during the St. Louis Air Quality Regional Study
MICHAEL WALKER, Yaping Zhang, Xiaochen Zuo, Raul Martinez, Dhruv Mitroo, Munkhbayar Baasandorj, Lu Hu, Dylan Millet, Jay Turner, Brent Williams, Washington University in St. Louis
Abstract Number: 588 Working Group: Source Apportionment
Abstract Organic aerosol (OA), which is known to influence global climate and adversely affect human health, can be enhanced through mixing of anthropogenic and biogenic emissions. The St. Louis Air Quality Regional Study (SLAQRS) was conducted in East St. Louis, Illinois between August and October of 2013, with a focus on the chemical properties of OA as urban pollution from the St. Louis metropolitan area was periodically impacted by isoprene-dominated biogenic emissions from the Ozarks to the southwest. The specific molecular composition of OA was measured with a Thermal Desorption Aerosol Gas Chromatograph (TAG), with supporting measurements of both gaseous and particulate organics with a Proton Transfer Reaction – Mass Spectrometer (PTR-MS) and High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS), respectively. Over 150 individual organic compounds have been quantified with hourly time resolution for a three week focus period that included several high isoprene events. Positive matrix factorization (PMF) analysis of these molecular markers was used to provide insight into the various OA sources. These analyses are compared with those from a recently developed chromatogram binning method, which allows for rapid PMF analysis of mass spectral datasets with chromatographic separation. This comparison highlights the advantages of each source apportionment method, with a particular focus on the isoprene-related OA.