HR: 0800h
AN: A41A-0001    [Abstracts]
TI: Continuous Estimates of Secondary Organic Aerosol From the Southeastern Aerosol Research and Characterization Study (SEARCH)
AU: * Saylor, R D
EM: rsaylor@atmospheric-research.com
AF: Atmospheric Research and Analysis, Inc., 2422 Meadowglen Trail, Snellville, GA 30078 United States
AU: Edgerton, E S
EM: ericedge@gte.net
AF: Atmospheric Research and Analysis, Inc., 410 Midenhall Way, Cary, NC 27513 United States
AU: Hartsell, B E
EM: bhartsell@atmospheric-research.com
AF: Atmospheric Research and Analysis, Inc., 730 Avenue F, Suite 220, Plano, TX 75074 United States
AB: Carbonaceous matter (organic matter + elemental carbon) comprises 30-45% of PM 2.5 mass in the southeastern U. S. Elemental carbon is formed during the incomplete combustion of organic compounds, primarily from fossil-fuel-powered vehicles. The organic material in PM 2.5 is a mixture of a myriad of organic compounds, a portion of which is emitted directly into the atmosphere (primary organic aerosol), and a portion of which that is formed from chemical reactions of reactive organic compounds in the atmosphere (secondary organic aerosol). In order to formulate effective control strategies for atmospheric particulate matter, it is important to gain a better understanding of the relative contributions and sources of primary and secondary organic aerosol. Continuous measurements of PM 2.5 mass and chemical composition have been performed since 1998 as part of the Southeastern Aerosol Research and Characterization study (SEARCH). The SEARCH measurement network consists of eight monitoring sites, organized as three urban-rural pairs in Georgia, Alabama, and Mississippi, and one urban-suburban pair in Florida. At each of these sites a variety of gaseous, particulate, and meteorological measurements are obtained on a routine basis, including continuous particulate elemental carbon via aethalometry and total particulate carbon via a Rupprecht & Patashnick Model 5400 carbon analyzer. In this work, we analyze hourly measurements of particulate elemental carbon and total carbon from the SEARCH network over 1999-2003 to estimate the contribution of secondary organic aerosol in the southeastern U.S. By using elemental carbon as a tracer of primary combustion-generated carbon emissions in conjunction with other continuously-measured gaseous species, we derive estimates of secondary organic aerosol mass as a fraction of total measured organic particulate mass. Urban-rural, seasonal, and weekday-weekend differences in secondary organic aerosol formation are examined.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting