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4.Environmental Analysis — Welty Road to SR 33, and northwesterly on SR 33 to Interstate 5 and further — destinations. The results of the CALINE screening analysis indicated no potential for violation of the 1-hour _ and 8-hour CO standards at any of the intersections under any of the analysis scenarios. The increase in the 1-hour maximum concentration due to the Project would be 0.2 ppm at the intersection of Blewett and Koster Roads. A persistence factor of 0.7 was used to estimate the — contribution of the project to ambient 8-hour CO concentrations. The project increment was added to the ambient 8-hour concentration in the project area. CO levels are projected to be significantly lower in the future due to emission control technology improvements in the — automobile fleet, attrition of older, high-polluting vehicles,and improved fuel mixtures. Such reductions would more than offset any effects of increase in traffic due to project and cumulative development. Thus, project-related and cumulative traffic would have a less-than-significant impact on local CO concentrations. Mitigation: No mitigation required. Impact 4.6.6: Project DPM Impact of Haul Trucks. Traffic generated by the project would have the potential to affect DPM concentrations along surface streets and near stagnation _ points such as major highways and heavily traveled and congested roadways.This impact is less than significant. This analysis was completed using the same general assumptions and methodology as for CO impacts,except that long-term (annual)concentrations were estimated to assess the impacts of DPM along the truck haul routes. Based on a maximum residency of 70 years,the predicted average annual DPM concentrations due to the project would be 0.0137,0.0101,and 0.0137 pg/m'for Haul Route Options 1,2,and 3, _ respectively. Using the DPM unit risk factor, as established by OEHHA, the maximum incremental carcinogenic risk is estimated to be 4, 3, and 4 in a million for Haul Route Options 1, 2,and 3,respectively. Thus,project-related and cumulative traffic would have a less-than- _ significant impact on local DPM concentrations within the Haul Route Options 1, 2, and 3. As discussed in Impact 4.6.4,typical residency for the area within two miles of the project is no more than 20 years. Thus,the use of a 70-year residency is conservative (protective of air quality and — health). Based on census data within two miles of the project,typical residency would be no more than . — 20 years. Under this condition,the predicted average annual DPM concentrations due to the project would be 0.0121,0.0089, and 0.0121 µg/m'on an annual basis for Haul Route Options 1, 2,and 3, respectively. Using the DPM unit risk factor,the maximum incremental carcinogenic - risk is estimated to be 4,3,and 4 in a million for Haul Route Options 1, 2, and 3, respectively. Thus,project-related and cumulative traffic would have a less-than-significant impact on local DPM concentrations under the Haul Route Options 1, 2,and 3 scenarios. However,as discussed RMC Pacific Vernalis Quarry Mining and Redamation Project 4.6-30 ESA/203015 Draft Environmental Impact Report May 2006