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CEQA requires that all feasible and reasonable mitigation measures be applied to the project to reduce the impacts from construction and operation on air quality. Implementation of Mitigation Measure 4.1-2, described in detail above, would reduce the production of VOCs. No other reasonable or feasible mitigation has been identified that will reduce impacts to air quality for the project. Potential Significant Effect Without appropriate mitigation, the project has the potential to impact air quality due to fugitive emissions of ozone precursors(NOx,VOC)from biosolids disposal. Description of Specific Impact Unloading, handling,and disposing of biosolids during the day of their receipt at the disposal facility will result in fugitive VOC emissions from natural evaporation, until they are buried and covered in the disposal pit area. Fugitive VOC emissions from biosolids were calculated using the "EPA WATERS Model." The concentration of volatile and semi-volatile organic compounds contained in biosolids was estimated to be 26.5 mg/l. The "VOC content" of the biosolids was calculated by summing the concentrations of volatile and semi-volatile organic compounds contained in Class A and Class B digested biosolids. The concentration of the volatile and semi-volatile organic compounds contained in biosolids was determined by the EPA for approximately 500 samples, obtained from 40 to 50 treatment plants located throughout the United States. The maximum value of the average VOC content reported for digested biosolids at Plant #1 through Plant #40 was approximately 26.5 mg/l. The predicted VOC emissions resulting from landfilling biosolids was determined using a biosolids/blend VOC content equal to 13.25 mg/1 (50% biosolids + cover mix). As described in the Draft EK biosolids may either be codisposed of with fly ash, when the fly ash waste stream is available, or disposed of by itself and covered with stockpiled soil overburden. The impacts of unmitigated VOC emissions of 19.2882 tpy per year are at a significant level. However, even with mitigation Project emissions of VOC would remain significant at a level of 10.3105 tpy. Therefore the Project would have a significant and unavoidable impact on air quality. Finding The impacts to air quality due to emissions of ozone precursors (NOx, VOC) from biosolids disposal are considered significant and unavoidable. All feasible and reasonable changes or alterations have been required in, or incorporated into, the project that substantially lessen the potentially significant effect as identified in the Final EIR. Brief Explanation of the Rationale for the Finding CEQA requires that all feasible and reasonable mitigation measures be applied to the project to reduce the impacts from construction and operation on air quality. Implementation of Mitigation Measure 4.1-3 and 4-1.4, described in detail above, would reduce the production of NOx and VOCs. No other reasonable or feasible mitigation has been identified that will reduce impacts to air quality for the project. Potential Significant Effect Without appropriate mitigation,the project has the potential to significantly impact air quality due to total emissions of ozone precursors(NOx,VOC)from the operation of the project. Description of Specific Impact - ------------------ Findings of Fact—Section 15091 March 15,2016 H. M. Holloway Landfill Modification Project Final Board of Supervisors 10