AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Investigating Chemical Reaction Pathways in the SE US Using Comprehensive Gas Chromatography
KELLEY C. BARSANTI, Melissa J. Roskamp, Wentai Luo, Lindsay E. Hatch, James F. Pankow, Portland State University
Abstract Number: 458 Working Group: Air Quality and Climate in the Southeast US: Insights from Recent Measurement Campaigns
Abstract Laboratory studies of secondary organic aerosol (SOA) formation have shown that the product distribution and SOA yields from anthropogenic and biogenic precursors vary significantly with the identity of the initial oxidant (e.g., OH/O$_3 vs. NO$_3), and other conditions such as NO$_x level (more specifically HO$_2/NO/NO$_2 ratios) and particle acidity. Thus it is known that anthropogenic emissions can have a significant influence on biogenic SOA formation; less clear are: 1) the degree to which these laboratory-observed effects are typically manifested under ambient conditions; and 2) how such processes might be best constrained in predictive models. In this work we performed a detailed analysis of two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC/TOFMS) data from the PINOT NOIR campaign (Particle Investigations at a Northern Ozarks Tower: NOx, Oxidant, Isoprene Research), centered in the Southeastern US. Utilizing GC×GC/TOFMS values for concentrations of volatile and semivolatile organic compounds (S/VOCs) together with data for trace gases and meteorology, we sought to identify and quantify important organic aerosol precursors and reaction products indicative of anthropogenically vs. biogenically influenced SOA formation mechanisms. The results have provided inputs to a suite of organic aerosol models of varying complexity for predicting the limits of SOA formation under a range of atmospherically relevant conditions. This research supports the goals of the Southeast Atmosphere Study (SAS), namely: 1) improved identification and quantification of dominant SOA precursors in the Southeastern US, and 2) further understanding of organic aerosol sources and the interplay between biogenic and anthropogenic emissions.