AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Atmospheric Observations of Secondary Aerosol Formation from Isoprene in the St. Louis Region during SLAQRS 2013
YAPING ZHANG, Raul Martinez, Dhruv Mitroo, Michael Walker, Christopher Oxford, Xiaochen Zuo, David Hagan, Jay Turner, Li Du, Dylan Millet, Munkhbayar Baasandorj, Lu Hu, Rodney J. Weber, Laura King, Brent Williams, Washington University in St. Louis
Abstract Number: 579 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Organic aerosol dominates global fine particulate matter composition. The contribution of secondary organic aerosol (SOA), which is not fully understood in terms of formation and transformation processes, to the total organic aerosol loading is typically substantial, even in urban regions. The global production of biogenic SOA is higher than anthropogenic SOA. In recent years it has been documented through laboratory and field studies that while the aerosol yield from isoprene is small in comparison to other biogenic precursors, it is emitted globally in large concentrations and can lead to large amounts of isoprene-derived SOA. Here, we present a study of field observations of SOA formation from isoprene measured by the thermal desorption aerosol GC/MS (TAG) during the St. Louis Air Quality Regional Study (SLAQRS) campaign that took place in East St. Louis, IL during the summer of 2013 (a site downwind of the Ozarks Plateau oak forests, known for high isoprene emissions). Factor analysis is applied to entire chromatograms, which includes thermal decomposition signal, resolved compounds, and unresolved complex mixtures (UCM), to investigate the major components of observed mass. Various pollutant impact periods (e.g., presence or absence of NOx, sulfate, isoprene SOA precursor gases, etc.) are contrasted and linked to the different formation pathways of isoprene SOA. These observations offer insights into the behaviors of isoprene SOA formation in/upwind the St. Louis region.