In August 2002, the South Coast AQMD’s Mobile Source Committee approved the “Health Risk Assessment Guidance for Analyzing Cancer Risks from Mobile Source Diesel Emissions.” This document provided guidance for analyzing cancer risks from diesel particulate matter from mobile sources at facilities such as truck stops and warehouse distribution centers. Subsequently, South Coast AQMD staff revised the aforementioned document to expand the analysis to provide technical guidance for analyzing cancer risks from potential diesel particulate emissions impacts from truck idling and movement (such as, but not limited to, truck stops, warehouse and distribution centers, or transit centers), ship hotelling at ports, and train idling. This revised guidance document titled, “Health Risk Assessment Guidance for Analyzing Cancer Risks from Mobile Source Diesel Idling Emissions for CEQA Air Quality Analysis” was presented to and approved by the South Coast AQMD’s Mobile Source Committee at its March 28, 2003 committee meeting. It is suggested that projects with diesel powered mobile sources use the following guidance document to quantify potential cancer risks from the diesel particulate emissions.
Disclaimer
The guidance document above is a legacy document and is maintained in its original form for historical reference. While the overall analytical framework and general approach described in the document remain valid, certain models, assumptions, and technical references are outdated and should not be relied upon for current CEQA analyses. Specifically, the document references the U.S. Environmental Protection Agency air dispersion model ISCST3 (Industrial Source Complex – Short Term, Version 3), which is no longer used. Current CEQA air toxics and health risk assessments should instead use AERMOD, consistent with current regulatory practice and guidance. In addition, users should be aware that emission factors, risk assessment parameters, meteorological datasets, and health risk benchmarks have been updated since the publication of this document. Project analyses should rely on the most recent and applicable guidance, models, and data from the agencies listed below.
For current CEQA air toxics and health risk assessment requirements, users should consult the latest information from: