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AR226-2343 ATTACHMENT 1 YEAR 2002 AIR DISPERSION MODELING ANALYSIS OF APFO EMISSIONS DuPont Washington Works Facility Parkersburg, West Virginia Prepared by: DuPont Engineering Technology (DuET) Environmental Section WUmmgton,DE 19898 October 17,2003 ASH027176 EXP015741 Year 2002 Air Dispersion Modeling Analysis October 17,2003 Page 2 1. Introduction DuPont conducted air dispersion modeling of APFO* emissions from its Washington Works facility located near Parkersburg, WV, Modeling was conducted to predict long-term ambient air concentrations ofAPPO resulting from actual plant emissions mat occurred during calendar year 2002. This report describes the APFO emissions inventory used in die modeling analysis, the meteorological data, me dispersion model and modeling procedures, prediction locations (receptor grid), and me results ofme modeling analysis. 2. Emissions Inventory The following emission inventory information has been assembled in order to conduct tfae air quality modeling: 1. Stack locations 2. Stack heights 3. Stack diameters 4. Stack gas exit temperatures 5. Stack gas flow rate or exit velocities 6. Detailed plant layout, including all building dimensions 7. Year 2002 estimated actual emissions. These emissions estimates are based upon product information and technical knowledge, including usage factors (quantity of APFO used per pound of dry product), production records, APPO recovery, and available stack test data. All of the stack parameters are presented in Table I, which shows me source representation for modeling purposes. The estimated actual emission rates ofAPFO, per source, are also presented in Table 1. Figure 1 presents the general locations ofthe APPO sources. 3. Meteorological Data One year ofon-site meteorological data for the calendar year 1996 was used in this study. Concurrent twice-daily upper air data from the upper air observation station located in Wilmington, OH was used along with on-site surface temperatures to obtain hourly mixing depths. Missing data and measured wind speeds of less than 1.0 m/s were treated consistent with me recommendations made in the EPA's "Meteorological Monitoring Guidance for Regulatory Modeling Applications<I).An anemometer height of 10 meters was used for the modeling analysis. 4. Model Selection The area surrounding Washington Works is primarily non-urban. The U. S. EPA procedures classify land use within 3 kilometers of the site by the Auer method 0). Previous review ofU. S. Geological Survey (USGS) maps, aerial photographs, and site visits clearly indicated that the area is well over 50% * "APFO" means ammonium perfluorooctanoate, and for the purposes of this report includes the anion of the acid perfluorooctanoic acid (PFOA). ASH027177 EXP015742 Year 2002 Air Dispersion Modeling Analysis October 17,2003 Page 3 non-urban. The Washington Works facility is located within the Ohio River valley, and is surrounded by significant terrain features on both sides of this river valley. As a result, terrain elevations were considered m the modeling analysis. ', The Industrial Source Complex Short Term Model (ISCST3) was used as the primary model to estimate long-term pollutant concentrations. ISCST3 is a steady-state Gaussian model recommended by the U.S. EPA. It is included in the "Guideline on Air Quality Models'^, which is codified as Appendix W to 40 CFR Part 51. It is appropriate fer modeling of pollutant emissions from multiple, industrial-type sources subjectto significant building downwash. The downwash algorithmsin tile ISCST3 model provide a representation of die aerodynamic downwash of a stack plume caused by complex buildingconfigurations typical of industrial facilities. Refined ISCST3 modeling was conducted using one year (1996) of sequential hourly meteorology fiom me from the on-site observation facility, as described above. 5. Receptor Selection A Cartesian grid of receptors was utilized in mis modeling analysis. This grid consisted of the following: Fenceline receptors with a 100m spacing between receptors Receptors beyond the fenceline wifh 100 m spacing on a 5 km by 7 km grid All receptors are located along or outside the plant fenceline. A Cartesian receptor grid ofthis type is considerably more dense than recommended by me U.S. EPA in the Guidelines on Air Quality Models for modeling a facility ofmis type. Terrain elevations for each of the receptors were imported from electronic files obtained from me U. S. Geological Survey (USGS) using the "highest" method to assign an elevation to each receptor. The receptor grid used in the modeling analysis is shown graphically in Figure 2. 6. Modeling Procedures The most recent version of ISCST3 (version 02035) was used in the air quality dispersion modeling of all receptors. All model options were set to the U.S. EPA regulatory default version of ISCST3. The model was run in the rural mode since the land area in the immediate vicinity of Washington Works is more than 50% rural. Any effects of aerodynamic downwash caused by structures adjacent to the modeled stack were included in the ISCST3 modeling analysis along with a summary of the building downwash input files (BPIP). Air quality dispersion modeling was conducted on an hour-by-hour basis using the one year of meteorological data described above. The APFO modeling results were summarized for me annual averaging time period. 7. Results The results of me modeling analysis indicate a maximum predicted annual average APFO concentration of 1.36 ug/m3. This maximum is located along the northern property fenceline, along me Ohio River, at UTM 442043 E, 4346883 N. The maximum predicted APFO concentration in an area where people may reside is 0.39 ug/m3. This prediction is located at UTM 442600 E, 4347600 N, on the Ohio side of the river. The results are presented graphically in Figure 3. ASH027178 EXPO-15743 Year 2002 Air Dispersion Modeling Analysis October 17,2TO3 Page 4 300RCE IB Table 1 X (MEIBBS) y |:METERS) *** EOIHT SOORCB DAX& *** BBSE ELEV. (Eeet) Emission Bate (Ib/br) 3TACE HBIGBT (tBBt) STACK TEMP. (DEG.F) 3TACS EXIX VBL. <tt/sec> STACK DrftMBTBR (feet) CEH242 TIM 862 T1E&T1F699 CFS274 R022EEF86 R022EEF89 T1F544 TH1852 COB 210 R022EEF6 R022EEF87 THG658 CFK268 C1CA-0205 COT 231 CDW232 T1V637 TIP 694 TIE 647 DF648 441954 442025 442091 441787 442069 442063 442084 441920 441960 442086 442058 441923 441774 442310 441S53 4419S2 442129 442104 442125 44210S 4346741 4346847 4348836 -4346744 4346627 4346635 4346835 43467B7 4346788 4346624 4346634 4346756 4348753 4346800 4346766 4346776 4346836 4346822 4346818 4346805 658.4 636.5 639.8 653.2 629.9 629.9 638.8 649.6 659.4 623.4 629.9 649.6 643.0 656.2 659.4 659.4 656.0 656.0 656.0 666.0 0.1047 0 0.1019 0.3424 0.000034 0.000068 0.4397 0.0037 0 0.0014 0.00034 0.0067 0.0071 0 0.3622 0.2626 0.0049 9.50E-03 0.0033 0.0024 114.5 149.9 1700 109.9 4&9 48.9 58.1 69.9 60.0 48.9 46.9 67.9 72.5 6.7 81.0 93.2 45.0 45.0 69.0 69.0 200.0 172.0 124.0 254.9 80.0 80.0 110.9 200.0 158.1 80.0 80.0 299.9 110.0 70.0 130.0 130.0 66.0 66.0 230.0 230.0 106.1 40.2 27.9 44.6 40.0 20.0 169.8 54.1 34.5 30.0 10.0 22.4. 29.1 84.9 28.4 23.6 15.2 15.2 57.0 57.0 0.50 1-33 4.00 0.69 2.00 2.00 1.50 1.86 1.30 2.50 ZOO 1.63 0.27 0.50 0.67 0.67 1.87 1.67 1.67 1.67 ASH027179 EXP015744 Year 2002 Air Dispersion Modeling Analysis October 17, 2003 Page5 Figure 1 f Source and Building Locations 'fe- ASH027180 EXP015745 4349000 Year 2002 Air Dispersion Modeling Analysis October 17,2003 Page 6 Figure 2 Receptor Grid Used in the Modeling Analysis 43480004 43470004 + i2 I 43460004++; 434500(H-+ ASH027181 EXP015746 4349000 4348000-1 434700(H 43460004 43450004 Year 21102 Air Dbperamn Modeling Analysis October 17,2003 Page? Figure 3 APFO 2002 Modeled Emissions Annual Average Concentrations (ug/m3) Contour Interval 0.1 ug/m3 ASH027182 EXP015747 ' Year 2002 Air Dispersion Modeling Analysis October 17,20B3 References (1) U. S. EPA. Meteorological Monitoring Guidance for Regulatory Modeling Applications, EPA454/R-99-005, Office of Air Quality Planning and Standards, February, 2000. (2) Auer, A. H., "Correlation of Land Use Cover with Meteorological Anomalies", Journal of.Applied Meteorology, Vol. 17, pp. 636-643,1978. (3) U. S. EPA. Guideline on Air Quality Models /Revised). EPA-450/2-78-027R-C, 2001. ASH027183 EXP015748