D.2.9 SOURCE IMPACT ANALYSIS RESULTS
Significant Impact Analysis
Carbon Monoxide
By modeling the emissions that would result from the project, G-P determined that the proposed project will not have a significant CO impact. Table D-21 presents the maximum predicted impacts from the significant impact analysis.
Table D-21
Averaging Period
|
Year
|
Maximum Predicted Impact (g/m3)
|
Receptor Location UTM Zone 15 (m)
|
Period Ending YYMMDDHH
|
Significant Impact Level (g/m3)
|
Monitoring De minimis Conc., (g/m3)
|
East
|
North
|
1-hour High 1st High
|
1986
|
323
|
291715
|
3956388
|
86080904
|
2000
|
--
|
1987
|
318
|
291714
|
3956338
|
87090301
|
1988
|
322
|
291714
|
3956338
|
88062323
|
1990
|
319
|
291714
|
3956338
|
90082206
|
1991
|
320
|
291715
|
3956363
|
91081204
|
8-hour High 1st High
|
1986
|
95
|
293900
|
3955300
|
86041524
|
500
|
575
|
1987
|
100
|
293500
|
3954600
|
87090908
|
1988
|
101
|
291715
|
3956388
|
88091024
|
1990
|
88
|
291714
|
3956313
|
90082208
|
1991
|
97
|
291715
|
3956463
|
91060708
|
The maximum 8-hour CO impact due to the project is below the SIL and monitoring de minimis concentrations. In addition, the maximum 1-hour impact value is also below the modeling significance level for that averaging period. Therefore, G-P did not perform a full NAAQS analysis for CO.
Nitrogen Dioxide
By modeling the emissions that would result from the project, G-P determined that the proposed project will have a significant NO2 impact out to approximately 4.5 km from the Mill. Table D-22 presents the maximum predicted impacts from the significant impact analysis.
Table D-22
Averaging Period
|
Year
|
Maximum Predicted Impact (g/m3)
|
Receptor Location UTM Zone 15 (m)
|
Period Ending YYMMDDHH
|
Significant Impact Level (g/m3)
|
Monitoring De minimis Conc., (g/m3)
|
East
|
North
|
Annual
|
1986
|
3.7
|
292201
|
3957272
|
3.8
|
1
|
14
|
1987
|
3.1
|
292151
|
3957273
|
3.3
|
1988
|
3.0
|
292101
|
3957274
|
3.4
|
1990
|
3.9
|
292326
|
3957270
|
4.0
|
1991
|
3.6
|
292301
|
3957270
|
3.7
|
The maximum annual NO2 impact due to the project is above the SIL but below the monitoring de minimis concentration of 1 and 14 g/m3, respectively. Therefore, G-P performed a full NAAQS analysis for NO2.
Sulfur Dioxide
By modeling the emissions that would result from the project, G-P determined that the project will have a significant SO2 impact out to 5.25 km. Table D-23 presents the maximum predicted impacts from the significant impact analysis.
Table D-23
Averaging Period
|
Year
|
Maximum Predicted Impact (g/m3)
|
Receptor Location UTM Zone 15 (m)
|
Period Ending YYMMDDHH
|
Significant Impact Level (g/m3)
|
Monitoring De minimis Conc., (g/m3)
|
East
|
North
|
Annual Mean
|
1986
|
0.6
|
292300
|
3958000
|
--
|
1
|
--
|
1987
|
0.5
|
292200
|
3958000
|
--
|
1988
|
0.5
|
292200
|
3957900
|
--
|
1990
|
0.6
|
292500
|
3957700
|
--
|
1991
|
0.7
|
292400
|
3958200
|
--
|
24-hour High 1st High
|
1986
|
4.7
|
296000
|
3954000
|
86041524
|
5
|
13
|
1987
|
4.2
|
294600
|
3954600
|
87011024
|
1988
|
5.3
|
294700
|
3954600
|
88032624
|
1990
|
4.0
|
293700
|
3954500
|
90122924
|
1991
|
5.0
|
296500
|
3955000
|
91110324
|
3-hour High 1st High
|
1986
|
20.4
|
296500
|
3955500
|
86070124
|
25
|
--
|
1987
|
20.7
|
296500
|
3955000
|
87042203
|
1988
|
24.2
|
294700
|
3954700
|
88030406
|
1990
|
21.2
|
296500
|
3955000
|
90050924
|
1991
|
14.3
|
296500
|
3955000
|
91120306
|
The maximum 24-hour SO2 impact due to the proposed project is 5.3 g/m3, which is above the SIL but below the monitoring de minimis concentrations of 5 and 13 g/m3, respectively. The maximum 3-hour and annual average impacts are below the respective modeling significance levels. Therefore, G-P performed a full NAAQS analysis for SO2.
Particulate Matter
By modeling the emissions that would result from the project, G-P determined that the project will have a significant PM10 impact out to 2.1 km. Table D-24 presents the maximum predicted impacts from the significant impact analysis.
Table D-24
Averaging Period
|
Year
|
Maximum Predicted Impact (g/m3)
|
Receptor Location UTM Zone 15 (m)
|
Period Ending YYMMDDHH
|
Significant Impact Level (g/m3)
|
Monitoring De minimis Conc., (g/m3)
|
East
|
North
|
24-hour High 1st High
|
1986
|
8.1
|
291897
|
3956770
|
86102824
|
5
|
10
|
1987
|
6.2
|
292391
|
3955890
|
87012424
|
1988
|
5.6
|
292441
|
3955890
|
88020324
|
1990
|
5.7
|
292391
|
3955890
|
90122224
|
1991
|
5.9
|
292391
|
3955890
|
91030224
|
Annual
|
1986
|
1.33
|
292101
|
3957274
|
--
|
1
|
--
|
1987
|
1.19
|
292101
|
3957274
|
--
|
1988
|
1.20
|
292101
|
3957274
|
--
|
1990
|
1.40
|
292351
|
3957270
|
--
|
1991
|
1.29
|
292351
|
3957270
|
--
|
The maximum 24-hour PM10 impact due to the project is above the SIL but below the monitoring de minimis concentrations of 5 and 10 g/m3, respectively. In addition, the maximum annual impact also slightly exceeds the modeling significance level. Therefore, G-P performed a full NAAQS analysis for PM10.
Summary
The significant impact analysis determined that the project emission increase would cause a maximum impact above the SILs and the EPA monitoring de minimis concentrations for several pollutants. Figures D-5, D-6, and D-7 in the application present the arrangement of the significant impact areas for these pollutants. Table D-25 summarizes the significant increment diameter (SID) for each pollutant and indicates if the project impact is above the de minimis monitoring concentration.
Table D-25
Pollutant
|
Averaging Time
|
SID (km)
|
Exceed de minimis Monitoring Conc?
|
SO2
|
24-hr
|
4.25
|
No
|
3-hr
|
0
|
--
|
Annual
|
0
|
--
|
NOX
|
Annual
|
4.8
|
No
|
PM10
|
Annual
|
2.0
|
--
|
24-hr
|
2.5
|
No
|
NAAQS Analysis
Nitrogen Dioxide
By modeling the total potential Mill emissions and competing source emissions, the analysis predicted the total impact to compare to the NAAQS. Table D-26 summarizes the NO2 model results.
Table D-26
Year
|
Annual Predicted Impact (ug/m3)(a)
|
Receptor Location UTM Zone 15 (m)
|
East
|
North
|
1986
|
27.2
|
291600
|
3956300
|
1987
|
28.3
|
291600
|
3956300
|
1988
|
29.8
|
291600
|
3956300
|
1990
|
23.6
|
291600
|
3956400
|
1991
|
25.0
|
291600
|
3956400
|
(a) maximum impact of two model runs with and without American Foundry Group
G-P added a background concentration of 10.2 g/m3 to the modeling result. As summarized in Table D-27, when adding the background concentrations, the annual concentration is 40.1 g/m3. This impact is less than the respective NAAQS of 100 g/m3. Therefore, G-P has demonstrated that the Mill emissions that reflect all project changes will not cause or contribute to a violation of the NAAQS.
Table D-27
|
Concentrations in g/m3
|
Averaging Period
|
Maximum Predicted Impact
|
Background Concentration
|
Total Concentration
|
NAAQS
|
Annual
|
29.8
|
10.2
|
40.1
|
100
|
Sulfur Dioxide
By modeling the total potential Mill emissions and competing source emissions, G-P determined that the maximum SO2 predicted impacts are 4,915, 133, and 14.5 μg/m3, for the 3-hour, 24-hour and annual averaging times, respectively. The maximum impact locations were in an area that did not require additional refined receptor grids. Table D-28 summarizes the SO2 model results.
Table D-28
Averaging
Period
|
Year
|
Maximum Predicted Impact (g/m3)
|
Receptor Location
|
Period
Ending
(YYMMDDHH)
|
East (m)
|
North (m)
|
Annual
|
1986
|
13.0
|
292400
|
3957700
|
--
|
1987
|
12.7
|
292700
|
3954100
|
--
|
1988
|
11.8
|
292200
|
3957600
|
--
|
1990
|
14.4
|
292500
|
3957700
|
--
|
1991
|
14.5
|
292500
|
3957700
|
--
|
24-Hour High Second High
|
1986
|
122
|
292700
|
3954100
|
86022024
|
1987
|
133
|
292600
|
3954100
|
87080424
|
1988
|
110
|
296500
|
3954000
|
88031324
|
1990
|
109
|
292700
|
3954100
|
90062224
|
1991
|
114
|
292700
|
3954100
|
91041924
|
3-Hour High Second High
|
1986
|
373
|
289700
|
3954100
|
86060815
|
1987
|
433
|
292700
|
3954100
|
87062412
|
1988
|
445
|
296000
|
3954000
|
88090403
|
1990
|
360
|
292700
|
3954100
|
90062218
|
1991
|
491
|
291500
|
3954100
|
91060921
|
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