Document 5kVEZZnXz14DwgLQ8mkMewqBD

AR226-2174 DISPERSION MODELING PROTOCOL Fluoropolymers Plant-A PFO Emissions DuPont Washington Works Prepared by: . Debbie J. Mulrooney DuPont Engineering Technology (DuET) Environmental Engineering Wilmington, DE 19898 August 6,2001 DJM 000589 E ID 502748 DuPont Washington Works Air Quality Modeling Protocol The following sections describe the dispersion m odeling m ethodology to be employed in order to assess th e ambient air concentrations o fAPFO (Ammonium Perfluoroctanoaie) resulting from emissions from the DuPont W ashington W orks facility. 1. Emission Source and Site Information The following inform ation will be assembled in order to conduct the air quality modeling: 1. Stack locations 2. Stack base elevations 3. Stack heights 4. Stack diam eters 5. Stack gas exit temperatures 6. Stack gas flow rate or exit velocities 7. Pollutant em ission rates 8. Building locations, dimensions and heights 9. Site boundary location 2. M odel Selection and Options W e propose the use o fthe Industrial Source Complex Short T erm 3 Model (1SCST3) to estimate pollutant concentrations. A ll modeling w ill b e done in accordance w ith the procedures in EPA's Guideline on A ir Quality M odels (Appendix W to Part 51). 3. Receptor Selection Two cartesian receptor grids w ill be used, a grid w ith 100-meter spacing extending out 5 km from the property line, and a grid w ith 500-meter spacing extending out 10 km from the property line. In addition, discrete receptors w ith 100-meter spacing w ill be placed on the plant property line. 4. M eteorological Data On-site surface w eather information was recorded for a full year in 1996. This data, along w ith upper air data from W ilmington, Ohio, w ill be used in the modeling. The data were processed for mnrfeling using the EPA RAMMET m eteorological preprocessor by Trinity Consultants. In all model runs, the calm processor option w ill be used. 5. M odeling Procedures Dispersion modeling w ill be performed using th e Industrial Source Complex 3 M odel (ISCST3). All model options w ill be set to the U.S. EPA regulatory default version o f ISC3. The model w ill be Draft Modeling Protocol 1 05/06/02 DJM 000590 EX05O2749 run in the rural mode since the land area in the im m ediate vicinity o f W ashington W orks is m ore than 50% rural- T he m odel w ill also be run using the elevated terrain option. All terrain elevations w ill be imported from DEM files provided by the USGS. ,, A ll em ission sources w ill be evaluated for downwash effects from surrounding buildings. Trinity Pnngnltantq BPIP model w ill be used to provide w ind direction specific building param eters. All buildings that could potentially impact the em ission sources w ill be included. On m ultiple tiered buildings, each tier w ill be entered as a separate building. M odeling w ill be perform ed to obtain the annual average concentration o f pollutant at all receptors outside the plant boundary. 6. R eport W e w ill prepare a report to be submitted to the W est V irginia DEP upon completion o fthe modeling analysis. This report w ill describe the procedures, results and conclusions o fthe study as described above. The report w ill include a w ind rose o f the meteorological data used and concentration isopleths o f the final predicted m odeling results. Copies o f all model input and output files w ill also be included. Draft Modeling Protocol 2 05/06/02 DJM 000591 E ID 502750