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5.1 AIR QUALITY <br /> were highest under cold temperature,peak load operating conditions. For 24-hour averages, <br /> impacts were highest under cold temperature,low load operating conditions,while annual <br /> average impacts were highest under high temperature conditions. <br /> TABLE 5.1-26 <br /> Results of Turbine Screening Procedure:Turbine Operating Conditions Producing Maximum Modeled Ambient Impacts by <br /> Pollutant and Averaging Period <br /> Pollutants and Averaging Periods Operating Case <br /> NOx, SO2 and CO: 1-, 3-and 8-hour averages Case 3 <br /> SO2 and PM,o: 24-hour averages Case 2 <br /> NOx, SO2 and PM,o: annual averages Case 7 <br /> 5.1.5.7 Refined Analysis <br /> The screening modeling analysis described above was used to determine which CTG/HRSG <br /> operating parameters (emission rates and stack parameters) would be used in the subsequent <br /> refined analyses. The refined analyses are described in detail in the following sections. <br /> 5.1.5.7.1 Normal Operations Impact Analysis <br /> The results of the AERMOD assessment for normal plant operations are summarized in <br /> Table 5.1-27 below. The following operating assumptions were used in developing the <br /> emission rates for each emissions unit and averaging period: <br /> 1-hour and 3-hour averages <br /> • CTG/HRSG at peak load,cold temperature (maximum impact case from screening <br /> analysis) <br /> • Auxiliary boiler in operation <br /> 8-hour average <br /> • CTG/HRSG in startup for 6 hours and at peak load,cold temperature for two hours <br /> (maximum impact case from screening analysis) <br /> • Auxiliary boiler in operation <br /> 24-hour averages <br /> • CTG/HRSG at minimum load,cold temperature for 24 hours (maximum impact case <br /> from screening analysis) <br /> • Auxiliary boiler in operation,maximum daily emission rates 14 <br /> • Cooling tower in operation <br /> 14 The auxiliary boiler is expected to operate only when the CTG is starting up or shutting down.However,to preserve <br /> maximum operational flexibility,the AQIA assumes that the auxiliary boiler may also operate during normal plant operation for <br /> up to 12 total hours per day. <br /> 5.1-38 SAC/371322/082410013(LEC_5.1_AIR_QUALITY.DOC) <br />