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Munn&Perkins Quarry Excavation Permit a processing and 0.0049 lb/ton of material for asphalt silo)were based on information contained in a North Carolina Department of Environmental Quality report entitled Salisbury Air Quality Monitoring Study.Analysis done by the Bay Area Air Quality Management District concluded that emissions from the production of rubberized asphalt are not significantly different than those from the production of conventional asphalt(BAAQMD,2002). The rubber additives in rubberized asphalt are not processed at a temperature high enough to cause the rubber to smoke or burn. The AERMOD dispersion model (Version 6.1.0)was used for the modeling analysis. AERMOD is the USEPA and SJVAPCD preferred dispersion model. It predicts both short-and Iong-term average concentrations. The model was executed using the regulatory default options(stack-tip downwash, buoyancy-induced dispersion, final plume rise),default wind speed profile categories, {� default potential temperature gradients, and no pollutant decay. Based on observation of the area surrounding the project site,rural dispersion coefficients we're applied in the analysis.Hourly emission scalars were applied accounting to the source operational schedule(i.e., 9 pm through 5 am)to account for the night-time emissions.Receptors were placed at locations within all residential uses surrounding the project site.Receptors were positioned as flagpole receptors at a height of 1.8 meters above the ground(typical breathing height). Surface meteorological data and upper air meteorological data from the Stockton station were obtained from the SJVAPCD and were used for the modeling analysis. The 5-year data set from 2005 to 2009 was used. The asphalt plant was treated as a point source with a release height of 42 feet,an average exhaust temperature of 101 degrees F, an exhaust flow rate of 27,104 dry standard cubic feet per minute,and a stack diameter of 77 inches.The asphalt silos were treated as volume sources with a release height of 65.6 feet and a horizontal dimension of 13 feet. Impacts and Mitigation Measures Impact 3.3.1: The project could create objectionable odors affecting a substantial number O of people. This impact would be Less than Significant. The SJVAPCD has determined minimal buffer distances for some common types of facilities that have been known to produce odors.For an asphalt batch plant,this distance is one mile. However, the asphalt plant at the project site is located less than one mile from many residences,the closest of which is about 0.3 miles(1,600 feet)north of the plant.Thus,dispersion modeling was conducted to evaluate concentrations of H2S and potential odor impacts at the nearest sensitive residential LLLIII receptors.Dispersion modeling analysis shows a potential maximum 1-Hour H2S concentration of 20 4g/m3. The California ambient air quality standard for H2S is 42 ug/m3. Thus,the project is not expected to result in ground-level concentration known to produce odor impacts4. Therefore,the impact of odors from the project is expected to be less than significant. In addition,the applicant will utilize a masking agent when rubberized asphalt is produced to minimize odors. Mitigation:None required. 4 According to the ARB,"breathing 112S at levels above the standard will result in exposure to a very disagreeable f 7 odor.In 1984,an ARB committee concluded that the ambient standard for H2S is adequate to protect public health and to significantly reduce odor annoyance."(ARB,2009b) 0 Munn&Perkins Quarry Excavation Permit 3.3-18 F$A1211086 Draft OR Apn12011