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NOTES TO TABLE 5.1 B-6 <br /> INVERSION BREAKUP FUMIGATION ANALYSIS <br /> Inversion breakup fumigation is generally a short-term phenomenon and was evaluated here as <br /> persisting for up to 90 minutes. SCREEN3 was used to model 1-hour unit impacts from the <br /> CTG/HRSG under 2.5 m/s winds and F stability (for fumigation impacts) and under all <br /> meteorological conditions (shown in the table as"Inversion Breakup Modeling Results from <br /> SCREEN3"). <br /> For longer-term averaging periods,impacts were calculated using the highest modeled impact <br /> from SCREEN3 for the corresponding averaging period. A sample calculation for 24-hour <br /> average PMlo for Case 1 is as follows: <br /> ■ For Case 1,1-hour average unit impact under inversion breakup conditions = 1.077 pg/m3 <br /> per g/s. <br /> ■ For Case 1,max. 1-hour average unit impact from SCREEN3 = 0.9341 }gig/m3 per g/s. <br /> ■ The appropriate unit impact for the 24-hour averaging period is calculated as 1.5 hours of <br /> inversion breakup fumigation plus 22.5 hours of operation under typical conditions (from <br /> SCREEN3): [(1.5*1.077 pg/m3 per g/s) + (22.5*0.9341 pg/m3 per g/s)] - 24 hrs = 0.943 <br /> pg/m3 per g/s. <br /> ■ For an emission rate of 1.314 g/s,the total 24-hour average PMlo impact under inversion <br /> breakup fumigation conditions is: 0.943 pg/m3 per g/s*1.314 g/s*0.4 [persistence factor <br /> for converting 1-hour average screening impact into 24-hour average concentration] = 0.427 <br /> ug/ms. <br />