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Environ Sci Technol

Title:		Origins of primary and secondary organic aerosol in Atlanta: results of time-resolved measurements during the Atlanta Supersite Experiment
Author(s):		Lim HJ; Turpin BJ;
Address:		"Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey 08901, USA"
Journal Title:		Environ Sci Technol
Year:		2002
Volume:		36
Issue:		21
Page Number:		4489 - 4496
DOI:		10.1021/es0206487
ISSN/ISBN:		0013-936X (Print) 0013-936X (Linking)
Abstract:		"Time-resolved ambient particulate organic (OC) and elemental carbon (EC) data measured in Atlanta, GA, during the Atlanta Supersite Experiment (August3-September 1, 1999) were investigated to determine the temporal trends of atmospheric carbonaceous aerosol and to examine the relative contributions of primary and secondary OC to measured particulate OC. Mean 1-h average concentrations (ranges in parentheses) of PM2.5 OC, EC, and total carbon were 8.3 (3.6-15.8), 2.3 (0.3-9.6), and 10.6 (4.6-24.6) microg of C m(-3), respectively, based on Rutgers University/Oregon Graduate Institute in situ thermal-optical carbon analyzer measurements. Carbonaceous matter (organic material 40%; EC 8%) comprised approximately 48% of PM2.5 mass in Atlanta. Primary and secondary OC concentrations were estimated using an EC tracer method. Secondary OC contributed approximately 46% of measured particulate OC, and 1-h average contributions ranged up to 88%. Vehicle emissions appear to be the dominant contributors to measured EC and primary OC concentrations based on temporal patterns of EC, primary OC, and CO. This research suggests that secondary OC concentrations in Atlanta were influenced by (1) 'fresh' secondary organic aerosol formed by photochemical reactions locally in the early afternoons as seen in the Los Angeles air basin and (2) 'aged' secondary organic aerosol transported from upwind regions or formed on previous days. Nocturnal peaks in secondary OC and ozone concentrations were observed on several days. The most probable explanation for this is the favorable partitioning of semivolatile organic compounds to the particulate phase driven by temperature decreases and relative humidity increases at night and vertical transport of regional pollutants from above to ground level"
Keywords:		Aerosols/*analysis Air Movements Carbon/*analysis Cities Environmental Monitoring Georgia *Hazardous Waste Organic Chemicals/analysis Periodicity Volatilization;
Notes:		"MedlineLim, Ho-Jin Turpin, Barbara J eng 2002/11/16 Environ Sci Technol. 2002 Nov 1; 36(21):4489-96. doi: 10.1021/es0206487"