Document pBay7n6QyVJn2bxo05zr9GGD
ATTACHMENT 2 AR226-1540
SEPTEMBER 2002 THROUGH AUGUST 2003 AIR DISPERSION MODELING ANALYSIS OF APFO EMISSIONS DuPont Washington Works Facility Parkersburg, West Virginia
RECEIVED OPPT NCIC 2003 October 31 8:25AM
Prepared for: West Virginia Department of Environmental Protection
Division of Air Quality 7012 MacCorkle Ave, SE Charleston, WV 25304-2943
Prepared by: DuPont Engineering Technology (DuET)
Environmental Section Wilmington, DE 19898
October 17, 2003
1. Introduction
September 2002 Through August 2003 Air Dispersion Modeling Analysis of APFO Emissions October 17, 2003 Page 2
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 of APFO resulting from actual plant emissions that occurred during the period of September, 2002 through August, 2003. This report describes the APFO emissions inventory used in the modeling analysis, the meteorological data, the dispersion model and modeling procedures, prediction locations (receptor grid), and the results of the modeling analysis.
2. Emissions Inventory
The following emission inventory information has been assembled in order to conduct the 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. Sept. 1, 2002 - Aug. 31, 2003 estimated actual APFO emissions
All of the stack parameters are presented in Table 1, which shows the source representation for modeling purposes. The estimated actual emission rates of APFO, per source, are also presented in Table 1. Figure 1 presents the general locations of the APFO sources.
3. Meteorological Data
One year of on-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 the recommendations made in the EPA's "Meteorological Monitoring Guidance for Regulatory Modeling Applications"(1). 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(2). Previous review of U. S. Geological Survey (USGS) maps, aerial photographs, and site visits clearly indicated that the area is well over 50% 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 in the modeling analysis.
"APFO" means ammonium perfluorooctanoate, and for the purposes of this report includes the anion of the acid perfluorooctanoic acid (PFOA).
September 2002 Through August 2003 Air Dispersion Modeling Analysis of APFO Emissions October 17, 2003 Page 3
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"(3), which is codified as Appendix W to 40 CFR Part 51. It is appropriate for modeling of pollutant emissions from multiple, industrial-type sources subject to significant building downwash. The downwash algorithms in the ISCST3 model provide a representation of the aerodynamic downwash of a stack plume caused by complex building configurations typical of industrial facilities. Refined ISCST3 modeling was conducted using one year (1996) of sequential hourly meteorology from the on-site observation facility, as described above.
5. Receptor Selection
A Cartesian grid of receptors was utilized in this modeling analysis. This grid consisted of the following:
Fenceline receptors with a 100 m spacing between receptors Receptors beyond the fenceline with 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 of this type is considerably more dense than recommended by the U.S. EPA in the Guidelines on Air Quality Models (U.S. EPA, 1998) for modeling a facility of this type. Terrain elevations for each of the receptors were imported from electronic files obtained from the 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 each 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 the annual averaging time period.
7. Results
The results of the modeling analysis indicate a maximum predicted annual average APFO concentration of 0.86 ug/m3. This maximum is located along the northern property fenceline, along the Ohio River, at UTM 442043 E, 4346883 N. The maximum predicted APFO concentration in an area where people may reside is 0.18 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.
September 2002 Through August 2003 Air Dispersion Modeling Analysis of APFO Emissions October 17, 2003 Page 4
Table 1
*** POINT SOURCE DATA ***
BASE Emission
STACK
STACK
STACK
STACK
SOURCE
X
Y
ELEV. Rate
HEIGHT TEMP. EXIT VEL. DIAMETER
ID
(METERS) (METERS)
(feet) (lb/hr)
(feet) (DEG.F) (ft/sec) (feet)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
CEH 242
441954 4346741
659.4 6.13E-02
114.5
200.0
106.1
0.50
TIM 662
442025 4346847
636.5
0
149.9
172.0
40.2
1.33
TIE&TIF 699
442091 4346836
639.8
0.167
170.0
124.0
27.9
4.00
CFS 274
441787 4346744
656.2 0.1211
109.9
254.9
44.6
0.69
RO22EEF86
442069 4346627
629.9 0.00045
48.9
80.0
40.0
2.00
RO22EEF89
442063 4346635
629.9 0.00045
48.9
80.0
20.0
2.00
TIF 644
442084 4346835
639.8
0
59.1
110.9
169.8
1.50
THI 652
441920 4346767
649.6 0.0034
69.9
200.0
54.1
1.96
CDB 216
441960 4346788
659.4
0
60.0
158.1
34.5
1.30
RO22EEF6
442086 4346624
623.4 0.00045
46.9
80.0
30.0
2.50
RO22EEF87
442058 4346634
629.9 0.00045
48.9
80.0
10.0
2.00
THG 658
441923 4346756
649.6 0.0063
67.9
299.9
22.4
1.63
CFK 268
441774 4346753
643.0 4.00E-03
72.5
110.0
29.1
0.27
C1CA-D 205
442310 4346800
656.2
0
6.7
70.0
84.9
0.50
CDT 231
441953 4346766
659.4 0.2226
81.0
130.0
28.4
0.67
CDW 232
441952 4346776
659.4 0.2255
93.2
130.0
23.6
0.67
TIV 697
442129 4346836
656.0 0.000114
45.0
66.0
15.2
1.67
TIF 694
442104 4346822
656.0 0.000114
45.0
66.0
15.2
1.67
TIE 647
442125 4346818
656.0
0
69.0
230.0
57.0
1.67
TIF 648
442109 4346805
656.0
0
69.0
230.0
57.0
1.67
September 2002 Through August 2003 Air Dispersion Modeling Analysis of APFO Emissions October 17, 2003 Page 5
Figure 1
Source and Building Locations
4349000
September 2002 Through August 2003 Air Dispersion Modeling Analysis of APFO Emissions October 17, 2003 Page 6
Figure 2
Receptor Grid Used in the Modeling Analysis
4348000
4347000
4346000
4345000
meters
439000
440000
441000
442000
443000
meters
444000
445000
September 2002 Through August 2003 Air Dispersion Modeling Analysis of APFO Emissions October 17, 2003 Page 7
Figure 3
September 2002 - August 2003 APFO Modeled Emissions
Annual Average Concentrations (ug/m3) Contour Interval 0.1 ug/m3
September 2002 Through August 2003 Air Dispersion Modeling Analysis of APFO Emissions October 17, 2003 Page 8
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.