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While dispersion modeling does not show a potentially significant impact based on HZS concentration, the record of previous odor complaints and the potential for increased sensitivity at night, would result in a potentially significant impact. Mitigation Measures: Measure 3.3.1. The operator shall incorporate additives to the rubberized asphalt mix in accordance with accepted industry standards. The objective of the additives shall be to reduce offensive odors associated with the production of rubberized asphalt. The operator shall consider technological improvements to reduce odors, as they become available, and incorporate if feasible. The operator shall ensure that loading, unloading, and material handling activities are carried out efficiently and without delays to avoid excessive odors. The operator shall use water trucks and/or sprinkler systems to reduce the potential dust associated with the operation. Significance After Mitigation: Dispersion modeling shows that the California ambient air quality standard for H2S would not be exceeded. The use of additives in the AC mix should reduce the odor associated with rubberized AC production. However, based on previous complaints, it cannot be demonstrated that all odor impacts to receptors within one mile would be reduced to the point where no future complaints would be received.Therefore,the impact is identified as significant and unavoidable. Noise Project-related noise exposure would affect nearby residential receivers between the hours of 9 p.m. and 5 a.m. Project-related noise from the Munn & Perkins asphalt plant and associated water truck, loader, and haul truck movements (on- and off-site) would be expected. The following impact criteria are applied to noise from these sources at the closest residential receivers to the project site. Significant project-related noise exposure would occur if the project stationary noise sources (e.g., asphalt plant) exceed the Countys nighttime limit of 45 dB hourly L,, or the nighttime maximum 65 dB L.,at off-site outdoor activity areas. Also, a significant impact would occur if noise from Proposed Project haul truck operations would exceed the applicable County noise exposure limits of 65 dB Ld„ (exterior) or 45 dB La„ (interior). Likewise, a significant impact would occur if noise exposure from project haul truck operations would produce noise exposure increases beyond the established FICON limits described above. Finally, a significant increase in nighttime awakenings of nearby residents due to project haul trucks on East River Road would be a significant noise impact. In this case, an increase in the probability of awakenings of 5 percent or more relative to the ambient condition (without the project) would be considered significant. The probability of nighttime awakenings was completed using the ANSI/ASA S12.6-2008 Part 6 recommendations/guidelines. The ANSI/ASA S12.9- 2008 Part 6 was used to estimate the probability of awakenings of existing residents in the project area with current conditions and for future conditions due to project-related haul truck operations. Current Conditions A total traffic volume of 182 project haul trucks was assumed to traverse a given section of East River Road in the project area during a typical 7-hour sleeping period (assumed to be 10 p.m.-5 a.m.). A given truck passby was assumed to produce an average event noise exposure level of 58 dB SEL within a residence 60 feet from the centerline of the roadway (83 dB exterior SEL). The probability of the residents located 60 feet from East River Road awakening at least once during the night from project haul truck noise was calculated to be approximately 93 percent. This probability is reduced to approximately 89 percent if the proposed haul truck noise exposure reduction parameters are applied; that is, if haul truck noise exposure is reduced by 4 dB using the proposed operating parameters presented above. San Joaquin County QX-89-0002/Aggregates Inc. Community Development Page 6