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4.Environmental Analysis Controls for non-road equipment engines with GARB-certified DPM filters and catalysts, while — using ultra low sulfur fuel(ULSD), would reduce DPM emissions from equipment by up to 85 percent.The traps catch the particulate matter and allow the catalysts to "burn"the DPM, while the ultra low sulfur fuel prevents the catalyst from becoming contaminated. With the use of — only CARB-certified catalysts in conjunction with ULSD, but without particulate filters, the control efficiency would be about 50 percent. By using catalyzed filters on some equipment and catalysts without filters on others,the overall DPM emission reduction would be about 70 percent. The best and most appropriate candidates for retrofitting would be the excavators, on- site haul trucks, and front end loaders.This equipment is used most often and most frequently. _ These engines would run hotter and would more readily reach critical internal temperature for proper operation of the catalyst in the DPM filter apparatus. To put project impacts into perspective,the average overall risk of a typical person in California should be understood. CARB conducted a study to estimate cancer risks from exposure to DPM in the State and to develop a risk reduction plan (GARB, 2000). The Study reported an estimated — statewide average ambient air concentration of DPM by using measured ambient air concentrations of surrogates to DPM in a receptor model. Based on the receptor modeling results, the statewide average cancer risk from exposure to diesel exhaust was estimated to be 540 in a — million. CARB report also states that cancer risks from diesel exhaust are about 70 percent of the total risks from exposure to all toxic air contaminants in the ambient air. The actual risk level at any particular location would require a site-specific study of all DPM emission sources in the area as well as the spatial relationships between the sources, stationary and mobile, and the location being analyzed. The analysis in this EIR estimates the increase in risk from the project only on nearby receptors. Since the estimated project-related increase in risk is greater than 10 in a — million,potentially feasible mitigations are considered. Mitigation Measures — Measure 4.6.4: The applicant shall either utilize new model year on-site machinery equipped with the best available DPM control technology,or retrofit its fleet of excavators, — on-site haul trucks, and front end loaders with catalyzed DPM filters to minimize DPM emissions, or, in those limited instances where the retrofit would impede the function or life of the equipment,or presents safety concerns,the applicant shall comply with alternative — measures developed by the Air Board. Impact Significance After Mitigation: If all the equipment identified(i.e., on-site diesel _ excavators, loaders, and haul trucks)had catalyzed particulate filters, with a DPM control efficiency of 85 percent,the maximum incremental lifetime cancer risks would be 7 and 9 cancers per million(assuming a 70-year exposure) and between 4 and 8 cancers per million (assuming a 20-year exposure) under the 1.7 and 4 million production rates. Implementation of this mitigation would reduce project cancer risk impacts to a less-than- significant impact. Impact 4.6.5: Project Carbon Monoxide Impact. Traffic generated by the project would — have the potential to affect CO concentrations along surface streets and near stagnation RMC Pacific Vernalis Quarry Mining and Reclamation Project 4.6-28 ESA 1203015 Draft Environmental Impact Report May 2006