Document rxLExxyoJmL2kbzawvD902YkV

AR226-2174 DISPERSION MODELING PROTOCOL Fluoropolymers Plant-APFO Emissions DuPont Washington Works Prepared by: Debbie J. Mutrooney DuPont Engineering Technology (DuET) Environmental Engineering Wihnington, DE 19898 August 6,2001 DJM000589 EID502748 DuPont Washington Works Air Quality Modeling Protocol The following sections describe tike dispersionmodeling methodology to be employed in order to assess the ambient air concentrations ofAPFO (Ammonium Perfluoroctanoate) resulting from emissions from the DuPont Washington Works facility. 1. Emission Source and Site Information The folio-wing information wffl be assembled in order to conduct the air quality modeling: 1. Stack locations 2. Stack base elevations 3. Stack heights 4. Stack diameters 5. Stack gas exit temperatures 6. Stack gas flow rate or exit velocities 7. Pollutant emission rates 8. Building locations, dimensions and heights 9. Site boundary location 2. Model Selection and Options We propose the use ofthe Industrial Source Complex Short Term 3 Model (ISCST3) to estimate pollutant concentrations- All modeling will be done in accordance with the procedures in EPA's Guideline on Air Quality Models (Appendix W to Part 51). 3. Receptor Selection Two cartesian receptor gridswill be used, a grid with 100-meter spacing extending out 5 km from the property line, and a grid with 500-meter spacing extending out 10 km from the property line. In addition, discrete receptors with 100-meter spacing wfll be placed on the plant property line. 4. Meteorological Data On-sfte surface weather information was recorded for a full year in 1996. This data, along with upper air data from Wihnington, Ohio, will be used in the modeling. The data were processed for modeling using the EPA RAMMET meteorological preprocessor by Trinity Consultants. In all model runs, the calm processor option will be used. 5. Modeling Procedures Dispersion modeling will be performed using the Industrial Source Complex 3 Model (ISCST3). All model options will be set to the U.S. EPA regulatory default version ofISC3. The model will be Draft Modeling Protocol 1 05/06/02 DJM000590 EID502749 run in the rural made since the land area in the immediate vicinity of Washington Works is more than 50% rural. The model will also be run using the elevated terrain option. All terrain elevations will be imported from DEM files provided by the USGS. , All emission sources wfll be evaluated for downwash effects from surrounding buildings. Trinity Consultants BPBP model will be used to provide wind direction specific buildingparameters. All buildings that could potentially impact the emission sources wfll be included. On multiple tiered buildings, each tier will be entered as a separate building. Modeling will be performed to obtain the annual average concentration ofpollutant at all receptors outside the plant boundary. 6. Report We will prepare a report to be submitted to the West Virginia DBP upon completion ofthe modeling analysis. This report will describe the procedures, results and conclusions ofthe study as described above. The report will include a wind rose of the meteorological data used and concentration isopleths of the final predicted modeling results. Copies of all model input and output files will also be included. Draft Modeling Protocol 2 05/06/02 DJM000591 EID502750