ARB Research Seminar

This page updated August 9, 2013

Using Individual Particle Chemical Signatures to Discriminate Between Gasoline and Diesel Particle Emissions

Kimberly A. Prather, Ph.D., Professor of Chemistry, Department of Chemistry & Biochemistry, University of California, San Diego

June 27, 2002
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


Identifying all important sources of ambient particles remains a key challenge to regulators in developing effective air pollution reduction strategies. Over the past decade, our group at the University of California at San Diego has made significant progress in this area by tracing individual particles back to their sources. Our approach utilizes a unique mass spectrometer instrument, designed and constructed by our group, that is capable of probing single particles in the atmosphere. With this instrument, we have amassed a source “signature” spectral library, composed of measurements from different source samples. In this presentation, we discuss results from recent and ongoing work in single particle source identification. In particular, we describe how different particle types evolve as they are transported from downtown L.A. to Riverside (part of SCOS97), new methods of particle classification using adaptive resonance (ART-2a), progress in quantitation, recent studies of vehicle emissions (LDV’s and HDV’s), and our future plans.

Speaker Biography

Kimberly A. Prather, Ph.D., is a professor of chemistry at the University of California, San Diego. Dr. Prather's research involves the development of analytical techniques for on-line characterization of aerosol particles. In the past ten years, Dr. Prather's research group has developed a unique technique, aerosol time-of-flight mass spectrometry (ATOFMS), which provides continuous information on single particle size and chemical composition. This instrument has been used extensively for source apportionment studies, as well as understanding the role of aerosol particles in global climate change, pollution, and health effects. Dr. Prather's most recent accomplishments include quantitation of the single particle data as well as extending the lower size limit of detection into the ultrafine size range (<100 nm).

Dr. Prather received her Ph.D. in 1990 from the University of California, Davis. Dr. Prather performed a postdoctoral fellowship at U.C. Berkeley from 1990-1992. In 1992, she became an assistant professor at U.C. Riverside where she resided until 2001 when she moved to U.C. San Diego as a Professor of Chemistry.

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