ARB Research Seminar

This page updated June 19, 2013

Advances in Our Understanding of the Major Sources Contributing to Ambient Particulate Matter in California

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

January 22, 2008
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


Distinguishing between the different sources contributing to atmospheric particulate matter represents a key hurdle for regulators working to establish the most effective reduction strategies for reducing air pollution levels in California.

Over the past decade, our group at the University of California, San Diego has been developing a unique source apportionment approach which relies on using single particle mass spectral "fingerprints" to identify and apportion particles in ambient studies. Source signature libraries have been created by sampling the emissions from spark ignition vehicles (gas), heavy duty vehicles (diesel), wood smoke, cooking, various industrial emissions, dust, ships, and sea salt. These libraries are now being used for on-the-fly apportionment of single particles in a number of atmospheric studies in California and other regions of the world. Results from two field studies conducted in San Diego and Riverside California will be discussed in this presentation to demonstrate the potential for this approach to help unravel the relative contributions of different major sources to atmospheric particulate matter. The presentation will conclude with highlights of our current research direction which involves using a mobile platform to study the seasonal and spatial variability of PM sources.

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.

For a complete listing of the ARB Research Seminars and the related documentation
for the seminars please view the Main Seminars web page