HR: 1340h
AN: A33B-0876 INVITED     [Abstracts]
TI: A Method for Chemical Characterization of the Ambient Organic Aerosol Soluble in Water by Group Speciation: Results From Urban Atlanta
AU: * Weber, R J
EM: rweber@eas.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332 United States
AU: Sullivan, A P
EM: amy.sullivan@eas.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332 United States
AB: Due to the chemical complexity of the organic fraction of ambient particles complete chemical speciation by single component analysis is currently not possible. This is especially true for polar compounds traditionally measured via a derivatization step prior to GC-MS analysis. However, with minor modifications, the application of existing methods for measuring natural organic matter (NOM) to atmospheric particles soluble in water can provide new insights into a large fraction of the ambient carbonaceous aerosol. This paper describes and reports results from a recently developed method that uses a two-step solid phase extraction (SPE) process with total organic carbon (TOC) detection. The method is capable of quantifying, by chemical group, approximately 80 percent of the water-soluble organic carbon (WSOC) in fine (PM2.5) ambient aerosol particles. During summer, this can be from 50 to 70 percent of the total organic aerosol. The chemical groups of WSOC that are quantified are an aliphatic group that is subdivided into acids with less than four to five carbons, neutrals, and bases, and an aromatic group that is divided into acids and phenols. Aspects of this separation method have been confirmed by C-NMR (Carbon - Nuclear Magnetic Resonance). The method is employed to characterize the summer organic aerosol in urban Atlanta Georgia and surrounding area by extraction and analysis of 24-hour integrated HiVol filter samples. Measurements at two sites are compared to a downtown site. One site was located next to a major highway, the other in a rural setting approximately 60 km west of the urban center. The preliminary results suggest most of the compounds that comprise the WSOC fraction are the secondary products of mobile source emissions.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005