# Evaluation of a Best Available Retrofit Technology (BART ) Scenario

for Alcoa’s Intalco Ferndale, Washington Facility

August 7, 2012

Prepared for:

Alcoa

Intalco Aluminum Corporation

Ferndale, Washington

Prepared by:

Exponent, Inc.

9 Strathmore Road

Natick, MA 01760

# 1

Figure 1. Alcoa Intalco plant layout in LCC coordin ates.2Table 1a. Base Case Scenario - Point Source Parameters – Maximum Daily1Emissions - Water On or Water OffSourceDescriptionLCCCoordinateLCCCoordinateStackHeightBaseElevationEffectiveStackExitVelExit TPM10EmissionFilterablePM2.5Conden.PM2.5SO2EmissionNOxEmissionX YDiam2Rate Emission Emission Rate Rate(km)(km)(m)(m)(m)(m/s)(K)(g/s)RateRate(g/s)(g/s)(g/s) (g/s)DSA1 -120.536 -14.914 19.8 65.40 3.733 12.98 363.71.81 0.097 1.48 37.41 0.00DSA2 -120.466 -15.15 19.8 63.90 3.733 13.05 363.7 1.81 0.097 1.48 37.41 0.00DSB3 -120.691 -14.958 17.9 62.20 5.957 5.17 353.1 1.81 0.097 1.48 37.41 0.00DSB4 -120.621 -15.195 17.9 61.40 5.957 5.17 353.1 1.81 0.097 1.48 37.41 0.00DSC5 -120.840 -15.000 17.9 59.70 5.723 4.90 355.1 1.81 0.097 1.48 37.41 0.00DSC6 -120.770 -15.238 17.9 59.00 5.723 4.79 355.1 1.81 0.097 1.48 37.41 0.00BAKEOVEN -121.011 -15.391 25.5 57.50 2.129 12.98 369.4 0.35 0.15 0.15 5.22 3.911Emission data is from spreadsheet “Maximum daily emissions for modeling 021507.xls” transmitted in theemail from Mike Palazzolo to Joe Scire dated February 16, 2007.2Sources DSA1 through DSC6 are effective stacks. DSA1 and DSA2 consists of 6 stacks each with a physical diameter of 1.524 meters for each stack, DSB3 and DSB4 consist of 26stacks each, with a physical diameter of 1.168 meters for each stack and DSC5 and DSC6 consist of 24 stacks each with a physical diameter of 1.1683 meters for each stack. The effectivediameter is calculated by multiplying the square root of the number of stacks by the physical diameter.Table 1b. Base Case Scenario + 20% SO2Reduction - Point Source Parameters – Maximum Daily1Emissions - Water On or Water OffSourceDescriptionLCCCoordinateLCCCoordinateStackHeightBaseElevationEffectiveStackExitVelExit TPM10EmissionFilterablePM2.5Conden.PM2.5SO2EmissionNOxEmissionX YDiam2Rate Emission Emission Rate Rate(km)(km)(m)(m)(m)(m/s)(K)(g/s)RateRate(g/s)(g/s)(g/s) (g/s)DSA1 -120.536 -14.914 19.8 65.40 3.733 12.98 363.71.81 0.097 1.48 29.93 0.00DSA2 -120.466 -15.15 19.8 63.90 3.733 13.05 363.7 1.81 0.097 1.48 29.93 0.00DSB3 -120.691 -14.958 17.9 62.20 5.957 5.17 353.1 1.81 0.097 1.48 29.93 0.00DSB4 -120.621 -15.195 17.9 61.40 5.957 5.17 353.1 1.81 0.097 1.48 29.93 0.00DSC5 -120.840 -15.000 17.9 59.70 5.723 4.90 355.1 1.81 0.097 1.48 29.93 0.00DSC6 -120.770 -15.238 17.9 59.00 5.723 4.79 355.1 1.81 0.097 1.48 29.93 0.00BAKEOVEN -121.011 -15.391 25.5 57.50 2.129 12.98 369.4 0.35 0.15 0.15 5.22 3.911Emission data is from spreadsheet “Maximum daily emissions for modeling 021507.xls” transmitted in theemail from Mike Palazzolo to Joe Scire dated February 16, 2007.2Sources DSA1 through DSC6 are effective stacks. DSA1 and DSA2 consists of 6 stacks each with a physical diameter of 1.524 meters for each stack, DSB3 and DSB4 consist of 26stacks each, with a physical diameter of 1.168 meters for each stack and DSC5 and DSC6 consist of 24 stacks each with a physical diameter of 1.1683 meters for each stack. The effectivediameter is calculated by multiplying the square root of the number of stacks by the physical diameter.3Table 2. All Scenarios - Point Source Parameters –Maximum Daily1Emissions – Water On or Water OffSourceDescriptionLCCCoordinateLCCCoordinateStackHeightBaseElevationEffectiveStackExitVelExit T PM10EmissionFilterablePM2.5Conden.PM2.5SO2EmissionNOxEmissionX YDiam2Rate Emission Emission Rate Rate(km)(km)(m)(m)(m)(m/s)(K)(g/s)RateRate(g/s)(g/s)(g/s) (g/s)CAST1-6 -120.392 -15.061 26.9 66.1 2.365 5.69 433.00.33 0.079 0.13 0.00 0.00CAST7-8 -120.415 -14.965 23.2 66.1 1.365 5.69 433.00.11 0.026 0.045 0.00 0.00CAST9-10 -120.422 -14.960 18.4 66.1 1.365 5.69 433.0 0.11 0.026 0.045 0.00 0.00CAST11-12 -120.433 -14.922 23.2 66.1 1.365 5.69 433.0 0.11 0.026 0.045 0.00 0.00188 -120.933 -15.393 36.1 58.5 1.462 5.34 Ambient 0.010 0.010 0.00 0.00 0.00189 -120.919 -15.088 36.1 58.5 1.287 3.63 Ambient 0.090 0.090 0.00 0.00 0.00191 -120.940 -15.395 36.1 58.5 1.287 3.63 Ambient 0.090 0.090 0.00 0.00 0.00195 -120.553 -15.394 17.7 63.1 0.61 4.29 343.0 0.080 0.080 0.00 0.00 0.00198 -120.957 -15.122 13.3 58.5 1.219 20.23 Ambient0.24 0.24 0.00 0.00 0.00199 -120.953 -15.121 13.3 58.5 1.219 20.23 Ambient0.24 0.24 0.00 0.00 0.00208 -121.006 -15.002 5.0 58.5 1.828 2.53 Ambient 0.076 0.076 0.00 0.00 0.00209 -121.095 -14.985 15.7 74.4 0.914 36.19 Ambient0.43 0.43 0.00 0.00 0.00210 -120.400 -15.282 9.4 65.2 0.762 3.11 395.0 0.00018 0.00018 0.00 0.00 0.00217 -120.360 -15.210 23.2 77.0 1.365 5.69 433.0 0.026 0.0035 0.007 0.00 0.00232 -120.931 -15.423 6.6 58.2 0.61 29.12 Ambient 0.097 0.097 0.00 0.00 0.00260 -120.925 -15.134 11.0 59.1 0.26 1.46 Ambient 0.025 0.025 0.00 0.00 0.00312 -120.922 -15.099 13.7 58.5 0.49 1.59 370.0 0.110.11 0.00 0.00 0.00313 -120.941 -15.104 13.7 58.5 0.49 1.59 370.0 0.110.11 0.00 0.00 0.00316 -120.858 -15.400 22.86 57.96 1.372 15.9 302.9 0.30 0.30 0.00 0.00 0.001 Emission data is from spreadsheet “Maximum dailyemissions for modeling 021507.xls” transmitted in the email from Mike Palazzolo to Joe Scire dated February 16, 2007.2 The cast house sources are modeled as effective stacks. CST1-6 contains 6 stacks each with a physical diameter of 0.9654 meters. The remaining effective stacks CAST 7-8,CAST 9-10, and CAST 11-12 contain 2 stacks each with a physical diameter of 0.9654 meters for each stack. The effective diameter is calculated by multiplying the square rootof the number of stacks by the physical diameter.3 LCC coordinates use the origin 49N, 121W, standard parallels 30N, 60N, datum NWS-84.4Table 3a. All Scenarios - Line Source Emission Rates used in CALPUFF (Water On – Wet Scrubber On)SourceDescriptionLineNumberLCCCoordinateBeg.XLCCCoordinateBeg.YLCCCoordinateEndXLCCCoordinateEndYReleaseHeightBaseElevationPM10EmissionRateFilterablePM2.5EmissionConden.PM2.5EmissionSO2EmissionRateNOxEmissionRate(km)(km)(km)(km)(m)(m)(g/s)RateRate(g/s)(g/s)(g/s) (g/s)WSLINEA1 1 -120.532 -14.845 -120.422 -15.219 16.4065.4 2.30 0.87 0.83 1.97 0.00WSLINEA2 2 -120.606 -14.867 -120.496 -15.241 16.4064.1 2.30 0.87 0.83 1.97 0.00WSLINEB1 3 -120.681 -14.892 -120.571 -15.266 16.4062.9 2.30 0.87 0.83 1.97 0.00WSLINEB2 4 -120.755 -14.914 -120.645 -15.288 16.4061.7 2.30 0.87 0.83 1.97 0.00WSLINEC1 5 -120.828 -14.936 -120.719 -15.309 16.4060.5 2.30 0.87 0.83 1.97 0.00WSLINEC2 6 -120.903 -14.958 -120.793 -15.332 16.4059.3 2.30 0.87 0.83 1.97 0.001Emission data is from spreadsheet “Maximum daily emissions for modeling 021507.xls” transmitted in theemail from Mike Palazzolo to Joe Scire dated February 16, 2007.Table 3b. All Scenarios + 20% SO2Reduction - Line Source Emission Rates used in CALPUFF (Water On – Wet Scrubber On)SourceDescriptionLineNumberLCCCoordinateBeg.XLCCCoordinateBeg.YLCCCoordinateEndXLCCCoordinateEndYReleaseHeightBaseElevationPM10EmissionRateFilterablePM2.5EmissionConden.PM2.5EmissionSO2EmissionRateNOxEmissionRate(km)(km)(km)(km)(m)(m)(g/s)RateRate(g/s)(g/s)(g/s) (g/s)WSLINEA1 1 -120.532 -14.845 -120.422 -15.219 16.4065.4 2.30 0.87 0.83 1.58 0.00WSLINEA2 2 -120.606 -14.867 -120.496 -15.241 16.4064.1 2.30 0.87 0.83 1.58 0.00WSLINEB1 3 -120.681 -14.892 -120.571 -15.266 16.4062.9 2.30 0.87 0.83 1.58 0.00WSLINEB2 4 -120.755 -14.914 -120.645 -15.288 16.4061.7 2.30 0.87 0.83 1.58 0.00WSLINEC1 5 -120.828 -14.936 -120.719 -15.309 16.4060.5 2.30 0.87 0.83 1.58 0.00WSLINEC2 6 -120.903 -14.958 -120.793 -15.332 16.4059.3 2.30 0.87 0.83 1.58 0.001Emission data is from spreadsheet “Maximum daily emissions for modeling 021507.xls” transmitted in theemail from Mike Palazzolo to Joe Scire dated February 16, 2007.5Table 4a. All Scenarios - Line Source Emission Rates used in CALPUFF (Water Off – Wet Scrubber Off – Period December 19 to 24Included)SourceDescriptionLineNumberLCCCoordinateBeg.XLCCCoordinateBeg.YLCCCoordinateEndXLCCCoordinateEndYReleaseHeightBaseElevationPM10EmissionRateFilterablePM2.5EmissionConden.PM2.5EmissionSO2EmissionRateNOxEmissionRate(km)(km)(km)(km)(m)(m)(g/s)RateRate(g/s)(g/s)(g/s) (g/s)WSLINEA1 1 -120.532 -14.845 -120.422 -15.219 16.4065.4 11.94 4.48 4.29 1.97 0.00WSLINEA2 2 -120.606 -14.867 -120.496 -15.241 16.4064.1 11.94 4.48 4.29 1.97 0.00WSLINEB1 3 -120.681 -14.892 -120.571 -15.266 16.4062.9 11.94 4.48 4.29 1.97 0.00WSLINEB2 4 -120.755 -14.914 -120.645 -15.288 16.4061.7 11.94 4.48 4.29 1.97 0.00WSLINEC1 5 -120.828 -14.936 -120.719 -15.309 16.4060.5 11.94 4.48 4.29 1.97 0.00WSLINEC26-120.903-14.958-120.793-15.33216.4059.311.944.484.291.970.001Emission data is from spreadsheet “Maximum daily emissions for modeling 021507.xls” transmitted in theemail from Mike Palazzolo to Joe Scire dated February 16, 2007.Table 4b. All Scenarios + 20% SO2Reduction - Line Source Emission Rates used in CALPUFF (Water Off – Wet Scrubber Off – Period December 19 to 24Included)SourceDescriptionLineNumberLCCCoordinateBeg.XLCCCoordinateBeg.YLCCCoordinateEndXLCCCoordinateEndYReleaseHeightBaseElevationPM10EmissionRateFilterablePM2.5EmissionConden.PM2.5EmissionSO2EmissionRateNOxEmissionRate(km)(km)(km)(km)(m)(m)(g/s)RateRate(g/s)(g/s)(g/s) (g/s)WSLINEA1 1 -120.532 -14.845 -120.422 -15.219 16.4065.4 11.94 4.48 4.29 1.58 0.00WSLINEA2 2 -120.606 -14.867 -120.496 -15.241 16.4064.1 11.94 4.48 4.29 1.58 0.00WSLINEB1 3 -120.681 -14.892 -120.571 -15.266 16.4062.9 11.94 4.48 4.29 1.58 0.00WSLINEB2 4 -120.755 -14.914 -120.645 -15.288 16.4061.7 11.94 4.48 4.29 1.58 0.00WSLINEC1 5 -120.828 -14.936 -120.719 -15.309 16.4060.5 11.94 4.48 4.29 1.58 0.00WSLINEC26-120.903-14.958-120.793-15.33216.4059.311.944.484.291.580.001Emission data is from spreadsheet “Maximum daily emissions for modeling 021507.xls” transmitted in theemail from Mike Palazzolo to Joe Scire dated February 16, 2007.6Table 5. All Scenarios - Parameters Used for Modeling Wet Scrubber Stacks as Line SourcesLine ID WetNumberBuilding DimensionsBuildingLineExitVolumetricBuoyancy Parameter (F') per Line1Scrubbersof StacksHeight(m)Width(m)Length(m)Separation(m)SourceWidth(m)Velocity(m/s)Flow(m3/sec)Wet ScrubbersOn(m4/s3)Wet ScrubbersOff(m4/s3)WSLINEA1 A1-A30 30 15.24 38.7 402.95 40.00 4.24 3.920 55.32 410.22 860.33WSLINEA2 A31-A60 30 15.24 38.7 402.95 40.00 4.24 3.920 55.32 410.22 860.33WSLINEB1 B1-B30 30 15.24 38.7 402.95 40.00 4.24 3.990 56.30 417.52 875.62WSLINEB2 B31-B60 30 15.24 38.7 402.95 40.00 4.24 3.990 56.30 417.52 875.62WSLINEC1 C1-C30 30 15.24 38.7 402.95 40.00 4.24 3.904 55.08 408.49 856.70WSLINEC2 C31-C60 30 15.24 38.7 402.95 40.00 4.24 3.904 55.08 408.49 856.701Note: The line source buoyancy parameters are basedon annual wet scrubber stack exit temperature measurements, exit velocity observations and stack diameters. The ambientair temperatures at the lower level (~10 m) of theon-site meteorology tower were used with the wet scrubber stack exit temperature measurements to compute average plume-ambienttemperature differences for the F' calculation. Thestack exit temperatures used in the calculation ofF’ is an annual average calculated from monthly exit temperatures averaged over theperiod 1995-1998. Two different values of F’ werecomputed, one for when the wet scrubbers are operational (i.e. F’ calculated to be 412.08 m4/s3) and the other for the period inDecember (19-24) when the wet scrubbers are not operational (i.e. F’ calculated to be 864.22 m4/s3).7Table 6.All Scenarios - Volume Source Parameters and Emission RatesReference LCCCoordinatesEmission RatesReleaseInitialInitialBasePM10 Filter.PM2.5Conden.PM2.5SO2NOxSource Source Description East North HeightσyσzElevation (g/s) (g/s) (g/s) (g/s) (g/s)ID(km)(km)(m)(m)(m)(m)251Anodebakebuildingmonitorroof-120.982-15.2422233.710.258.70.130.130.000.000.00252Anodeblockholeblower-120.982-15.2422233.710.258.70.120.120.000.000.00257ARodshopcrustrecoverydischarge-120.948-15.1230.00210.000320.000.000.00to trucksfrombins#1and#24.61.071.0758.5257BRodshopcrustrecoverydischarge-120.906-15.1120.00210.000320.000.000.00to trucksfrombins#1and#24.61.071.0758.5259ARodshopcrustrecoverydischarge-120.948-15.1230.00300.000460.000.000.00to trucksfrombins#1and#24.61.071.0758.5259BRodshopcrustrecoverydischarge-120.906-15.1120.00300.000460.000.000.00to trucksfrombins#1and#24.61.071.0758.5280Annexcathodeassemblyarearoof-120.983-15.0130.0540.0540.000.000.00vent18.38.978.5158.5282 Annexladlerebuildarearoofvents-120.952 -14.990 18.3 8.97 8.51 58.5 0.380.38 0.00 0.00 0.001 Emission data is from spreadsheet “Maximum dailyemissions for modeling 021507.xls” transmitted in the email from Mike Palazzolo to Joe Scire dated February16, 2007.8Table 7.All Scenarios - Area Source Parameters and EmissionRatesSouthwest CornerEmission RatesFilterableCondensableLCCCoordinatesReleaseInitialBaseTotal PM10PM2.5PM2.5SO2NOxSource ID Source DescriptionEast (km) North (km) Ht (m)σz(m)Elevation(m) Area (m2) (g/s/m2) (g/s/m2) (g/s/m2) (g/s/m2) (g/s/m2)239 Fugitive dust from vehicles traffic on paved roads -121.149 -14.601 5 10 60 720000 0.000000400.000000059 0 0 0241 Facility-wide from gas combustion (fugitive) -121.149 -14.601 15 15 60 720000 0.00000022 0.00000023 0 0.000000042 0.000003273 Alumina ore handling fugitive dust -121.149 -14.601 15 15 60 720000 0.000000053 0.000000008 0 0 01 For plant-wide combustion emissions (sources 241and 273) the release height is assumed to be equalto the average building height of 15 meters. For fugitiveemissions from paved roads the release height is assumed to be 5 m.2 Emission data is from spreadsheet “Maximum dailyemissions for modeling 021507.xls” transmitted in the email from Mike Palazzolo to Joe Scire datedFebruary 16, 2007.3 Unit emission is g/s/m2.Table 8.All Scenarios - 50 Other Sources Modeled as VolumeSources – Parameters and Emission Rates used for Modeling these SourcesReference LCCCoordinatesEmission RatesRelease Initial Initial Base PM10Filter.PM2.5Conden.PM2.5SO2NOxSourceIDOthers1Source DescriptionEast(km)North(km)Height(m)σy(m)σz(m)Elevation(m)(g/s) (g/s) (g/s) (g/s) (g/s)Sourcessmallerthan0.1g/scombined (no SO2depositionor NOx)– no-120.665-15.0764.61.071.0762.00.3580.3070.000.000.00Sourceslargerthan0.1g/sOthers2combined (no SO2depositionor NOx)– no-120.665-15.0764.61.071.0762.00.8490.74140.000.000.00Others3SourcesincludingSemissions – no depoO2andNOxsition-120.665 -15.076 4.6 1.07 1.07 62.0 0.1722 0.1676 0.00 0.1574 2.3481 Emission data is from spreadsheet “Maximum dailyemissions for modeling 021507.xls” transmitted in the email from Mike Palazzolo to Joe Scire datedFebruary 16, 2007

# 9

Table 9. Year 2003 – Base Case Scenario Summary Tab le for Visibility Impact using

Method 6 with the 20 th 

# Best Day Natural Background.

Class I area Larges t

Deltadeciview (dv) 98 th 

# p erc en tile

Delta-d ecivie w

(dv) Receptor location

of 98 th 

# percentile Ending of 24h

period – 98 th



# p ercentile No. of days

above

0.5dv No. of days

above 1dv

Alpine Lakes W. 2.120 1.244 -44.951 -148.052 Day 5 7 h0 36 11

Glacier Peak W. 2.024 1.161 -26.585 -90.864 Day 2 20 h0 37 14

Goat Rocks W. 1.880 0.500 -42.084 -253.680 Day 300 h0 8 4

Mount Adams W. 1.698 0.456 -46.144 -301.967 Day 13 1 h0 7 2

Mount Rainier NP 3.169 0.843 -66.233 -215.874 Day 276 h0 22 6

North Cascades NP 1.822 1.376 -45.145 -20.878 Day 187 h0 65 19

Olympic NP 4.108 2.363 -156.407 -118.354 Day 57 h 0 59 29

Pasayten W. 1.241 0.866 75.074 -8.015 Day 212 h0 30 2



# Table 10. Year 2004 – Base Case Scenario Summary Ta ble for Visibility Impact using

Method 6 with the 20 th 

# Best Day Natural Background.

Class I area Larges t

Deltadeciview (dv) 98 th 

# p erc en tile

Delta-d ecivie w

(dv) Receptor location

of 98 th 

# percentile Ending of 24h

period – 98 th



# p ercentile No. of days

above

0.5dv No. of days

above 1dv

Alpine Lakes W. 2.266 0.965 -41.471 -167.771 Day 2 00 h0 37 7

Glacier Peak W. 1.867 1.156 -28.244 -63.988 Day 2 27 h0 38 8

Goat Rocks W. 1.697 0.579 -42.084 -253.680 Day 138 h0 10 5

Mount Adams W. 1.688 0.472 -46.144 -301.967 Day 21 1 h0 6 4

Mount Rainier NP 2.429 1.052 -66.233 -215.874 Day 71 h0 26 10

North Cascades NP 1.947 1.395 -37.000 -38.856 Day 180 h0 56 16

Olympic NP 4.672 1.858 -163.305 -107.414 Day 268 h 0 53 21

Pasayten W. 1.612 0.871 -0.294 -1.344 Day 182 h0 33 4



# Table 11. Year 2005 – Base Case Scenario Summary Ta ble for Visibility Impact using

Method 6 with the 20 th 

# Best Day Natural Background.

Class I area Larges t

Deltadeciview (dv) 98 th 

# p erc en tile

Delta-d ecivie w

(dv) Receptor location

of 98 th 

# percentile Ending of 24h

period – 98 th



# p ercentile No. of days

above

0.5dv No. of days

above 1dv

Alpine Lakes W. 1.522 0.881 -43.731 -146.271 Day 2 23 h0 23 3

Glacier Peak W. 1.217 0.736 -26.585 -90.864 Day 2 23 h0 23 2

Goat Rocks W. 0.625 0.317 -42.084 -253.680 Day 117 h0 3 0

Mount Adams W. 0.616 0.357 -39.372 -308.278 Day 26 4 h0 2 0

Mount Rainier NP 0.996 0.629 -66.233 -215.874 Day 122 h0 15 0

North Cascades NP 1.821 1.138 -36.755 -1.225 Day 256 h0 32 8

Olympic NP 4.130 2.136 -173.846 -99.043 Day 237 h 0 45 24

Pasayten W. 1.189 0.659 -0.294 -1.344 Day 346 h0 13 2

# 10

Table 12. Year 2003 – Base Case Scenario with a 20% Reduction in Sulfur, Summary

Table for Visibility Impact using Method 6 with the 20 th 

# Best Day Natural

Background.

Class I area Larges t

Deltadeciview (dv) 98 th 

# p erc en tile

Delta-d ecivie w

(dv) Receptor location

of 98 th 

# percentile Ending of 24h

period – 98 th



# p ercentile No. of days

above

0.5dv No. of days

above 1dv

Alpine Lakes W. 1.774 1.046 -44.951 -148.052 Day 5 7 h0 29 8

Glacier Peak W. 1.688 0.978 -26.585 -90.864 Day 2 20 h0 31 7

Goat Rocks W. 1.573 0.411 -42.084 -253.680 Day 300 h0 6 3

Mount Adams W. 1.416 0.378 -46.144 -301.967 Day 13 1 h0 5 2

Mount Rainier NP 2.673 0.699 -66.233 -215.874 Day 276 h0 16 5

North Cascades NP 1.533 1.168 -45.145 -20.878 Day 187 h0 48 10

Olympic NP 3.491 1.199 -156.407 -118.354 Day 57 h 0 50 23

Pasayten W. 1.034 0.721 2.068 -28.226 Day 215 h0 21 1



# Table 13. Year 2004 – Base Case Scenario with a 20% Reduction in Sulfur, Summary

Table for Visibility Impact using Method 6 with the 20 th 

# Best Day Natural

Background.

Class I area Larges t

Deltadeciview (dv) 98 th 

# p erc en tile

Delta-d ecivie w

(dv) Receptor location

of 98 th 

# percentile Ending of 24h

period – 98 th



# p ercentile No. of days

above

0.5dv No. of days

above 1dv

Alpine Lakes W. 1.903 0.805 -41.471 -167.771 Day 2 00 h0 28 7

Glacier Peak W. 1.566 0.961 -28.244 -63.988 Day 2 27 h0 30 6

Goat Rocks W. 1.410 0.476 -42.084 -253.680 Day 138 h0 7 3

Mount Adams W. 1.403 0.388 -44.220 -293.034 Day 13 8 h0 5 2

Mount Rainier NP 2.035 0.883 -66.233 -215.874 Day 71 h0 21 6

North Cascades NP 1.638 1.174 -37.000 -38.856 Day 180 h0 46 11

Olympic NP 4.009 1.558 -163.305 -107.414 Day 268 h 0 48 19

Pasayten W. 1.351 0.733 -0.294 -1.344 Day 182 h0 24 4



# Table 14. Year 2005 – Base Case Scenario with a 20% Reduction in Sulfur, Summary

Table for Visibility Impact using Method 6 with the 20 th 

# Best Day Natural

Background.

Class I area Larges t

Deltadeciview (dv) 98 th 

# p erc en tile

Delta-d ecivie w

(dv) Receptor location

of 98 th 

# percentile Ending of 24h

period – 98 th



# p ercentile No. of days

above

0.5dv No. of days

above 1dv

Alpine Lakes W. 1.292 0.739 -43.731 -146.271 Day 2 23 h0 17 1

Glacier Peak W. 1.010 0.613 -26.585 -90.864 Day 2 23 h0 15 1

Goat Rocks W. 0.518 0.260 -42.084 -253.680 Day 117 h0 2 0

Mount Adams W. 0.509 0.299 -39.372 -308.278 Day 26 4 h0 1 0

Mount Rainier NP 0.844 0.519 -66.233 -215.874 Day 122 h0 9 0

North Cascades NP 1.518 0.959 -36.755 -1.225 Day 256 h0 28 6

Olympic NP 3.564 1.824 -264.485 -76.761 Day 348 h 0 41 21

Pasayten W. 1.001 0.543 -0.294 -1.344 Day 346 h0 8 1