AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Chemical Characterization of Isoprene- and Monoterpene-Derived SOA Tracers in PM2.5 Collected from Centerville, AL, during SOAS 2013
MATTHIEU RIVA, Lindsay Yee, Sri Hapsari Budisulistiorini, Eric Edgerton, Stephanie Shaw, Eladio Knipping, Allen H. Goldstein, Zhenfa Zhang, Avram Gold, Jason Surratt, University of North Carolina at Chapel Hill, Chapel Hill, NC
Abstract Number: 301 Working Group: Air Quality and Climate in the Southeast US: Insights from Recent Measurement Campaigns
Abstract Secondary organic aerosol (SOA) formed from the atmospheric oxidation of biogenic volatile organic compounds (BVOCs) accounts for a substantial mass fraction of fine particulate matter (PM2.5). Isoprene is the most abundant non-methane hydrocarbon and BVOC emitted into the Earth’s atmosphere and is mainly present (along with monoterpenes) in the southeastern U.S. during summer. Recent work has shown that anthropogenic pollutants, such as sulfate aerosol, enhance oxidation products of isoprene and monoterpene as a source of SOA. For isoprene SOA formation, acidified sulfate aerosol enhances the reactive uptake of isoprene-derived epoxides, whereas monoterpene SOA appears to be enhanced by sulfate aerosol via heterogeneous reactions. Ozonolysis can enhance nucleation monoterpenes. However, impact of environmental conditions (NOx level, aerosol acidity, sulfate, and primary aerosol) on biogenic SOA formation arising from isoprene and monoterpene oxidation remains unclear. Improving our knowledge of isoprene and monoterpene SOA formation will be the key to improving existing air quality models in order to elucidate impacts of anthropogenic activities on SOA formation from biogenic VOCs.
In order to investigate the impacts of anthropogenic activities on BSOA and confirm previous laboratory findings, PM2.5 samples were collected during the Southern Oxidant and Aerosol Study (SOAS) in summer 2013 at the Centerville, AL, site using high-volume samplers. Filters were collected at least twice per day on regular sampling days, and four times per day on intensive sampling days. We present the chemical characterization of these samples using ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) and gas chromatography interfaced with electron ionization mass spectrometry (GC/EI-MS) with prior trimethylsilylation. Real-time gas- and particle-phase chemical data obtained from collocated instruments have been used in order to investigate the detailed linkages between anthropogenic activities and biogenic SOA.