Toxicity of Ambient Particulate Matter: The Role of Peroxides as Generated by Aerosol Particles in Southern California


This page updated January 26, 2010

Chair’s Air Pollution Seminar

Wednesday, March 3, 2010
1:30 pm - 3:30 pm, PST
Sierra Hearing Room, Second Floor
1001 I Street, Sacramento

This event is being Webcast, click here to view
Webcast viewers: Please send your questions during broadcast to: sierrarm@calepa.ca.gov
Presentation is available at this link

 Toxicity of Ambient Particulate Matter:
The Role of Peroxides as Generated
by Aerosol Particles in Southern California

Suzanne Paulson, Ph.D.

Department of Atmospheric Sciences
University of California, Los Angeles
Hydrogen peroxide (H2O2) is an important member of the family of reactive oxygen species (ROS), which have been associated with a range of adverse health outcomes. Previous results indicated that freshly collected ambient aerosols generate large amounts of H2O2 in aqueous solutions. This study probed the source of that H2O2 activity by examining the chemical composition of ambient aerosols and the activity of source materials. Fine and coarse mode aerosols were collected at three sites: two in Riverside (one upwind and one downwind of a major freeway), and one on the UCLA campus.

  • H2O2 generation by coarse mode aerosols at these sites was strongly correlated with soluble iron, zinc, and copper.  H2O2 generation increased as the acidity of the particle extraction solutions increased.

  • In contrast, H2O2 generation activity for the fine mode aerosols was correlated with a combination of metals and organics, including quinones. Significant correlation was found with soluble iron, zinc, and copper when their concentrations were relatively high. H2O2 generation was highest when the particle extraction solutions were moderately acidic.

  • Lab experiments showed that ammonium sulfate particles do not generate H2O2, while secondary organic aerosol and diesel/biodiesel exhaust particles generate substantial quantities of H2O2.

Susan Paulson, Ph.D., has been a professor in the Department of Atmospheric & Oceanic Sciences at University of California, Los Angeles since 1994. She earned a B.A. in Chemistry from the University of Colorado, an M.S. in Plant Biology at the University of Illinois, and a Ph.D. in Environmental Engineering Science from the Caltech. Dr. Paulson's current research is focused on impacts of tiny particles that are produced by both natural and human activities on the Earth’s climate and on human health. Professor Paulson has received a Faculty Early Career Development (CAREER) award from the National Science Foundation for her research.


For information on this seminar please contact:
Ralph Propper at (916) 323-1535 or send email to: rpropper@arb.ca.gov

For information on this Series please contact:
Peter Mathews at (916) 323-8711 or send email to: pmathews@arb.ca.gov

For a complete listing of the ARB Chairman's Series and the related documentation for
each one of the series please check this page 

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