Contributions to Secondary Organic Aerosol during 2009/2010 in Cleveland, Ohio

JOHN H OFFENBERG (1), Michael Lewandowski (1), Mohammed Jaoui (2), Terrance Gerald (2), Kenneth Docherty (2), Tadeusz E. Kleindienst (1)

(1) US EPA / NERL, RTP, NC. (2) Alion Science and Technology, RTP, NC.

     Abstract Number: 665
     Last modified: May 14, 2010

Abstract
A precursor specific, organic tracer-based method was used to estimate the secondary contributions of precursor hydrocarbons to ambient organic carbon concentrations in PM2.5 during August 2009 and February 2010 in two downtown locations in Cleveland and one site adjacent to Chippewa Lake near Medina, Ohio. One hundred eighty ambient PM2.5 samples were collected on a 24 hour schedule and analyzed for (1) secondary organic aerosol tracer compounds, (2) levoglucosan, a compound used as a tracer for biomass burning, and (3) organic and elemental carbon. For isoprene, alpha-pinene, beta-caryophyllene, and toluene, the secondary contributions to ambient organic carbon concentrations were estimated using measured tracer concentrations and previously published, laboratory-determined mass fractions. Additionally, 180 parallel samples were collected for $^(14)C analysis to determine the fraction of new carbon. The relative contributions of the four precursor hydrocarbons to the measured organic carbon concentration across the three locations as well as a comparison with the measure of the relative importance of carbon of petrogenic origin relative to ‘new’ carbon will be presented.