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Modeling the Atmospheric Concentrations of Individual Gas-Phase and Particle-Phase Organic Compounds

Fraser, M. P. and Kleeman, M. J. and Schauer, J. J. and Cass, G. R. (2000) Modeling the Atmospheric Concentrations of Individual Gas-Phase and Particle-Phase Organic Compounds. Environmental Science and Technology, 34 (7). pp. 1302-1312. ISSN 0013-936X. https://resolver.caltech.edu/CaltechAUTHORS:20160622-152147558

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Abstract

An Eulerian photochemical airshed model is adapted to track the concentrations of individual vapor-phase, semivolatile, and particle-phase compounds over the carbon number range from C_1 to C_(34). The model incorporates primary emissions of organic gases and particles from sources based on recent source tests. These emissions are processed through a photochemical airshed model whose chemical mechanism has been expanded to explicitly follow the reaction or formation of 125 individual vapor-phase organic compounds plus 11 lumped vapor-phase compound groups. Primary organic compounds in the particle phase can be disaggregated at will from a lumped primary organic compound mass category; in the present model application, 31 individual primary particulate organic compounds are tracked as they are transported from sources to receptor air monitoring sites. The model is applied to study air quality relationships for organics in California's South Coast Air Basin that surrounds Los Angeles during the severe photochemical smog episode that occurred on September 8−9, 1993. The ambient concentra tions of all normal alkanes and most aromatic hydrocarbons are predicted within the correct order of magnitude over 6 orders of magnitude concentration change from most abundant gas phase to least abundant particulate species studied. A formal evaluation of model performance shows that, with the exception of a few outliers, the concentrations of over 100 organic compounds studied were reproduced with an average absolute bias of ±47% and with roughly equal numbers of compounds underpredicted (58) versus overpredicted (46). The time series of observed aromatic hydrocarbons concentrations are reproduced closely, production of methylglyoxal from aromatic precursors is tracked, and the predicted olefinic hydrocarbon concentrations decline dramatically in concentration due to chemical reaction and dilution during downwind transport as is observed in the ambient monitoring database. This ability to simultaneously account for the concentrations of individual gas-phase and particulate organic compounds lays a foundation for future calculations of secondary organic aerosol formation and gas/particle repartitioning in the atmosphere.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/es9901922DOIArticle
http://pubs.acs.org/doi/abs/10.1021/es9901922PublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/es9901922PublisherSupporting Information
Additional Information:© 2000 American Chemical Society. Received for review February 17, 1999. Revised manuscript received November 11, 1999. Accepted December 6, 1999. This research was supported by the Electric Power Research Institute under Agreement RP3189-03 and by the Caltech Center for Air Quality Analysis.
Funders:
Funding AgencyGrant Number
Electric Power Research Institute (EPRI)RP3189-03
Caltech Center for Air Quality AnalysisUNSPECIFIED
Issue or Number:7
Record Number:CaltechAUTHORS:20160622-152147558
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20160622-152147558
Official Citation:Modeling the Atmospheric Concentrations of Individual Gas-Phase and Particle-Phase Organic Compounds M. P. Fraser, M. J. Kleeman, J. J. Schauer, and, and G. R. Cass Environmental Science & Technology 2000 34 (7), 1302-1312 DOI: 10.1021/es9901922
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68609
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:22 Jun 2016 22:57
Last Modified:03 Oct 2019 10:15

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