Document 3QYdYRB3v2mxXkGxvJ78wzLRy

AR226-2331 CADocumcnKi and Settings\BARTONC\Dc5i<top\c8\modeling How should we address the request for short-term air expo assessment? 1. Refine Input Parameters Optimize emission rates Explore possible transformation of C8 to other compounds Explore impact of plume depletion Review operating schedule 3. Establish Baseline Rerun ISCST3 using any refined parameters and appropriate averaging time 04/10/03 4B.Minimize uncertainty in the analysis (next page) Minimize Uncertainty Option 1 Option 2 Minimize Model Uncertainty EPA recognizes model uncertainty, especially in short timeframes but doesn't specify over-prediction. Scholarly paper purports air dispersion models conservative by over 2X - only one reference and still doesn't offer alternative 'Best approach - Conduct modeling using EPA model (AERMOD scheduled to be approved) compare results with ISC Assume 1 to 2 months; cost of new meteorological data and modeling time (< $5000) Substitute Monitoring Data for Modelin Most likely less conservative than modelin Where and when to sample are critical issu Edge Moor sampling program was $50-60, based on 5 sampling events (locations) meas 24-hr average concentrations at 5 locations. 04/10/03