Actions to Update the Methodology for Estimating
Premature Death Associated with Fine Airborne
Particulate (PM2.5) Exposure

As part of the Air Resources Board's development of the Emission Reduction Plan for Ports and Goods Movement, ARB staff performed a health impacts analysis for domestic and international goods movement activities. At the April 20, 2006 Board meeting, staff presented the results of this analysis, which can be found in Appendix A at http://www.arb.ca.gov/planning/gmerp/gmerp.htm. Following the presentation, staff was directed by the Board to update the health impacts methodology to reflect recent health information on PM2.5 exposures and premature death. On August 21, 2006, a public workshop was held to discuss our approach for revising the methodology and our timeline for completing the work. Staff reviewed all relevant literature and completed a draft report incorporating public comments received at the workshop. A formal review of the updated methodology and analysis was conducted by a peer review committee appointed by the University of California. The committee is composed of experts in the fields of epidemiology, air quality measurement, risk management, health effects of air pollution, and biostatistics. A draft staff report was presented to the Board at its meeting on May 22, 2008, and it was also discussed at a public workshop on June 25, 2008. Public comments were received through July 11, 2008.

On October 24, 2008 the ARB released the staff report titled "Methodology for Estimating Premature Deaths Associated with Long-term Exposure to Fine Airborne Particulate Matter in California." This staff report presents an updated relative risk factor for the association between PM2.5 and premature death. It also provides an updated threshold level for this relationship. The staff report, which can be downloaded at the link below, includes revisions made in response to public comments on the draft staff report. It also contains a summary of the public comments and ARB staff's responses. Copies of the original written comments have been compiled in a separate supplement to the staff report. Also, references cited in the staff report are available for public inspection.

At the December 9, 2009 meeting of the ARB, the Board directed staff to withdraw the 2008 staff report and to reassess the methodology developed to quantify the association between PM2.5 exposure and premature death. The Board requested this new assessment because of concerns over the development of the concentration-response factor. A draft report will be published for public review and comment in the Spring of 2010.

This fact sheet provides background on particulate matter and the health risks it poses.

For more information, please contact Dr. Linda Smith
at lsmith@arb.ca.gov or (916) 327-8225.