Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 1, 1999 | public
Journal Article

Source Contributions to the Size and Composition Distribution of Atmospheric Particles: Southern California in September 1996

Abstract

An air quality model that follows the evolution of single particles in the atmosphere has been combined with new emissions measurements and then used to predict the size distribution and chemical composition of the airborne fine particle mixture observed at Long Beach, Fullerton, and Riverside, CA, during September 1996. Model predictions show good agreement with ambient measurements of particle size and chemical composition at all three air monitoring sites. The air quality model is used to separately track individual particles released from different sources as they evolve over time. Four major classes of particles are observed:  (1) large mineral dust and road dust particles that accumulate only small amounts of secondary aerosol products; (2) primary combustion particles (released initially from diesel vehicles, noncatalyst gasoline-powered vehicles, and food processing) that grow by accumulation of secondary reaction products; (3) sea salt particles that are almost completely transformed by conversion from NaCl to NaNO_3 during transport across the air basin; and (4) sulfate-containing nonsea salt background particles advected into the air basin from upwind over the ocean. The sulfate-containing nonsea salt background particles have an initial PM2.5 concentration of only 8 μg m^(-3), but they accumulate significant secondary aerosol reaction products to produce a largely nitrate-containing aerosol having a PM2.5 concentration of 40 μg m^(-3) by the time that the air masses studied here reach Riverside, CA.

Additional Information

© 1999 American Chemical Society. Received for review June 2, 1999. Revised manuscript received September 7, 1999. Accepted September 14, 1999. This research was supported by the U.S. Environmental Protection Agency under Grant No. R826371-01-0 and by funds granted to the Caltech Center for Air Quality Analysis. Thanks are due to Dr. Kent Hoekman and Dr. Steve Ziman of Chevron for assistance with this research. Collection of ambient air quality data was supported by the U.S. Environmental Protection Agency under Grant No. R824970-01-0. The authors would like to thank Dr Xinqiu Zhang of the South Coast Air Quality Management District for his help in preparing emissions inventories for the South Coast Air Basin during the study period. Model results shown in this paper were produced using a Beowulf class parallel computer developed and supported by Thomas Sterling, Jan Lindheim, John Salmon, Paul Angelino, and other members of the Center for Advanced Computer Research at the California Institute of Technology.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023