Document Exepda2qkVL1Xo3VZ8qZ9eJYR

AR226-2307 Scope and Cost of Air Dispersion Modeling Cathie Barton DuPont 03/10/03 Overview of the Scope I Can hire contractor or use in- house modeling resources Data Gathering > Modelim Interpreta of Resul 03/10/03 I Your input is critical here -vs^s^ Data Gathering Meteorological Data Terrain elevation maps Stack Parameters - Location (coordinates) - Height - Temperature - Stack gas vertical velocity - Diameter - Emission rates for each compound Plot Plan - Exact locations of all sources - Property line - Building locations and heights Modeler typi gets this information you 03/10/03 Standard Model and Methodo EPA's preferred model: Industrial Sou Complex Short Term 3 (ISCST3) Mode Procedures detailed in EPA's Guidelin Air Quality Models (40 CFR 51 Append http://www.epa.gov/scram001/guidanc de/appw_01.pdf 03/10/03 Modeling Output Model will calculate hourly concentra in ug/m3 across a study area (5 km x km for example) Model will average those concentrati over a designated time period (24 ho monthly, yearly) Concentration contours showed exte different ug/m3 Also shows numerical values (top 10 the study area and locations) 03/10/03 Technicolor Example of Outp 2480000-H 247BOOO 2476000-1 W1000-\ 2472000H 2-170000-^ 2468000-1 2466000-'- 608000 610000 612000 614000 616000 618000 620000 62200 Interpretation of Results Compare maximum averaged concentration to appropriate "thres value - Maximum annual average would be compared to a chronic toxicity value - Maximum hourly average would be compared to an acute toxicity value 03/10/03 Cost and Timing Expect about 50 man-hours (_10 h Costs - Outside modeler charges approximate $150/hr - Meteorological data could be up to $1 - Estimate around $8,500 for an averag 03/10/03