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Published September 1993 | public
Journal Article

Mathematical modeling of urban organic aerosol: properties measured by high-resolution gas chromatography

Abstract

Primary fine aerosol emissions from a variety of urban sources have been quantitatively characterized via high-resolution gas chromatography to obtain organic mass distribution fingerprints. To assess the degree of secondary organic aerosol formation in urban areas, a transport model is used to predict the distribution of ambient organic aerosol characteristics that would exist at various sites in the Los Angeles Basin if the primary organic emissions were transported without chemical reaction. Comparisons between the model predictions and ambient measurements show substantial agreement for the nonpolar organics, suggesting that ambient concentrations of this organic fraction result directly from primary emissions. In contrast, ambient concentrations of fine acidic organic aerosols are significantly underpredicted by the model, indicating that secondary formation is important for acidic organics. On the basis of the observed differences between model predictions and measured properties of acidic organics, it is estimated, using monthly averages, that up to 18-27 % of the elutable organic aerosol present in the Los Angeles atmosphere may be secondary in origin.

Additional Information

© 1993 American Chemical Society. Received for review October 23, 1992. Revised manuscript received May 21, 1993. Accepted May 25, 1993. Portions of this paper were presented at the 1989 AAAR Conference in Reno, NV, and at the 1990 ASCE Specialty Conference on Environmental Engineering in Washington, DC. This work was supported by EPA Grant R-813277-01-0 and by gifts to the Environmental Quality Laboratory. This paper has not been subject to the EPA's peer and policy review and, hence, does not necessarily reflect the views of the EPA. Mention of trade names or commercial products does not constitute EPA endorsement or recommendation for use.

Additional details

Created:
August 20, 2023
Modified:
October 25, 2023