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4.6 Air Quality V and C. Mitigation measures to reduce NOx impacts to less than significant are not I. technically feasible;thus, after mitigation this would remain a significant impact. Other technologies exist to control NOx emissions from engines, such as the use of the fuel ` additive PuriNOx,and/or the use of urea injection system in combination with a reducing catalyst. However, these technologies have not been widely tested in the types of engines for the project.Also, they have been known to affect engine operation efficiencies and may create secondary environmental impacts. Current control technologies associated with the 6" concrete,asphalt,and sand dryer equipment generally apply to fugitive dust emissions and not NOx. There are no current control technologies that when applied together would reduce the total NOx emissions from the project to less than significant(that is,a 90 percent r reduction). Impact 4.6.3: Project Odor Impact. The project could result in objectionable odors.This is a less-than-significant impact. r Though offensive odors from stationary sources rarely cause any physical harm, they still remain unpleasant and can lead to public distress, generating citizen complaints to local governments. The occurrence and severity of odor impacts depend on the nature, frequency and intensity of the source; wind speed and direction; and the sensitivity of receptors. The CEQA Guidelines recommend that odor impacts be considered for any proposed new odor sources located near existing receptors, as well as any new sensitive receptors located near existing odor sources. Generally, increasing the distance between the receptor and the source will mitigate odor impacts. ` The Valley Air District 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. The project will locate the asphalt batch plant(within the southwestern section of the Plant ` Site) at a distance of between one-half and one mile from the nearest sensitive receptors. However, as noted in the GAMAQI,the prevailing wind direction(from the northwest to the southeast including a±45 degree buffer) will tend to reduce potential odor impacts on receptors r located to the northeast of the project site and although to a lesser extent, on receptors located to the southwest of the project site.Thus,the frequency and intensity of any odor impacts would be expected to be reduced,as the nearby receptors are northeast and southwest of the Plant Site. hi. Furthermore, odor emissions would be reduced by the implementation of BACT(such as a duo drum system and routing smoke or odor releases from the silos back to the drum mixer's low- NO.burner), but odor emissions could still occur. Also storage of the finished product could increase the overall odor intensity in the area. Diesel truck emissions could also be an odor source. However, since trucks would pass by the nearest receptors without stopping, and would not idle their engines nearby,the exhaust emissions and associated odors would disperse before affecting a substantial number of people. Dispersion modeling analysis shows a potential I-Hour 112S concentration of 28 µg/m'. The California ambient air quality standard for 112S is 42 pg/m'.Thus,the facility is not expected to L result in ground-level concentration known to produce odor impacts. Therefore,the impact of odors from the project is expected to be less than significant. If complaints are received regarding RMC Pacific Vernalis Quarry Mining and Reclamation Project 4.6-25 ESA/203015 Draft Environmental tmpact Report May 2006 fes,