WYOMING STATE IMPLEMENTATION PLAN

Regional Haze

Addressing Regional Haze Requirements for Wyoming Mandatory

Federal Class I Areas Under 40 CFR 51.309(g)

Grand Teton National Park

Yellowstone National Park

Bridger Wilderness

Fitzpatrick Wilderness

North Absaroka Wilderness

Teton Wilderness

Washakie Wilderness

January 7, 2011

Prepared By

The Wyoming Department of Environmental Quality

Air Quality Division

Herschler Building, 122 West 25th Street

Cheyenne, Wyoming 82002
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Table of Contents

 Page

Chapter 1. General Plan Provisions ............................................................................................1 

Chapter 2. Wyoming Class I Areas; Baseline, Natural and Current Visibility Conditions ..3 

2.1 Description of the Yellowstone Monitoring Site (YELL2) Class I Areas ....................3 

2.1.1 Grand Teton National Park ............................................................................3 

2.1.2 Teton Wilderness ...........................................................................................5 

2.1.3 Yellowstone National Park ............................................................................7 

2.1.4 Monitoring Strategy and Location - YELL2 Monitoring Site .......................8 

2.1.5 Assessment of Baseline, Natural and Current Conditions - YELL2

 Class I Areas ................................................................................................10 

2.2 Description of the North Absaroka Monitoring Site (NOAB1) Class I Areas ...........13 

2.2.1 North Absaroka Wilderness .........................................................................13 

2.2.2 Washakie Wilderness ...................................................................................15 

2.2.3 Monitoring Strategy and Location - NOAB1 Monitoring Site ....................16 

2.2.4 Assessment of Baseline, Natural and Current Conditions - NOAB1

 Class I Areas ................................................................................................18 

2.3 Description of the Bridger Monitoring Site (BRID1) Class I Areas ..........................21 

2.3.1 Bridger Wilderness ......................................................................................21 

2.3.2 Fitzpatrick Wilderness .................................................................................23 

2.3.3 Monitoring Strategy and Location - BRID1 Monitoring Site ......................24 

2.3.4 Assessment of Baseline, Natural and Current Conditions - BRID1

 Class I Areas ................................................................................................26 

Chapter 3. Pollutants Causing Visibility Impairment in Wyoming Class I Areas ...............29 

3.1 Yellowstone National Park, Grand Teton National Park and Teton Wilderness ........32 

3.2 North Absaroka and Washakie Wilderness Areas ......................................................35 

3.3 Bridger and Fitzpatrick Wilderness Areas ..................................................................37 

Chapter 4. Statewide Emission Inventory ................................................................................40 

4.1 Introduction .................................................................................................................40 

4.2 SOx Emission Inventory ..............................................................................................41 

4.3 NOx Emission Inventory .............................................................................................42 

4.4 OC Emission Inventory...............................................................................................43 

4.5 EC Emission Inventory ...............................................................................................44 

4.6 Fine PM Emission Inventory ......................................................................................45 

4.7 Coarse PM Emission Inventory ..................................................................................46 

4.8 Ammonia Emission Inventory ....................................................................................47 

4.9 Inventories Utilized For Emissions Projections ..........................................................47 

4.10 PRP18b .....................................................................................................................48 
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Chapter 5. Source Apportionment and Regional Haze Modeling ..........................................50 

5.1 Overview .....................................................................................................................50 

5.1.1 Source Apportionment Analysis - PSAT and WEP .....................................50 

5.1.2 Regional Haze Modeling - CMAQ ..............................................................51 

5.2 Major Source Categories Contributing to Haze in Wyoming .....................................53 

5.2.1 PSAT Regional Contribution to Sulfate on 20% Worst Days .....................54 

5.2.2 PSAT Regional Contribution to Sulfate on 20% Best Days ........................57 

5.2.3 PSAT Regional Contribution to Nitrate on 20% Worst Days .....................61 

5.2.4 PSAT Regional Contribution to Nitrate on 20% Best Days ........................64 

5.2.5 WEP Potential Contribution to OC on 20% Worst Days ............................67 

5.2.6 WEP Potential Contribution to OC on 20% Best Days ...............................70 

5.2.7 WEP Potential Contribution to EC on 20% Worst Days .............................72 

5.2.8 WEP Potential Contribution to EC on 20% Best Days ................................74 

5.2.9 WEP Potential Contribution to Fine PM on 20% Worst Days ....................76 

5.2.10 WEP Potential Contribution to Fine PM on 20% Best Days .....................78 

5.2.11 WEP Potential Contribution to Coarse PM on 20% Worst Days ..............80 

5.2.12 WEP Potential Contribution to Coarse PM on 20% Best Days .................82 

5.3 CMAQ 2018 Projected Visibility Conditions .............................................................84 

5.3.1 CMAQ Modeling Breakdown by Pollutant for 20% Worst Days ...............85 

Chapter 6. Best Available Retrofit Technology (BART) .........................................................89 

6.1 Introduction .................................................................................................................89 

6.2 SO2: Regional SO2 Milestone and Backstop Trading Program .................................90 

6.3 Overview of Wyoming’s BART Regulations .............................................................92 

6.4 SIP BART Requirements From EPA’s Regional Haze Rule......................................92 

6.5 Facility Analysis .........................................................................................................99 

6.5.1 FMC Wyoming Corp. - Granger Facility ....................................................99 

6.5.2 FMC Wyoming Corp. - Green River - Westvaco Facility ...........................99 

6.5.3 General Chemical - Green River Works ....................................................100 

6.5.4 PacifiCorp - Jim Bridger Power Plant .......................................................102 

6.5.5 PacifiCorp - Dave Johnston Power Plant ...................................................104 

6.5.6 PacifiCorp - Naughton Power Plant ...........................................................106 

6.5.7 PacifiCorp - Wyodak Power Plant .............................................................108 

6.5.8 Basin Electric Power Cooperative - Laramie River Station ......................109 

Chapter 7. Reasonable Progress Goals ...................................................................................113 

7.1 Overview ...................................................................................................................113 

7.2 Process for Establishing Reasonable Progress Goals ...............................................114 

7.3 Four Factor Analysis Performed for Wyoming Sources...........................................115 

7.3.1 Detailed Description of the Four Factors ...................................................116 

7.3.2 Source Selection Process for Four Factor Analysis ...................................117 

7.3.3 PacifiCorp Dave Johnston Electric Generating Station .............................118 
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7.3.4 Mountain Cement Company, Laramie Plant .............................................120 

7.3.5 Oil and Gas Exploration and Production Field Operations .......................123 

7.4 309 SIP and 309(g) ...................................................................................................127 

7.5 Setting Reasonable Progress Goals ...........................................................................127 

7.6 Demonstration That the RPGs for 20 Percent Best and Worst Days are

 Reasonable ................................................................................................................128 

Chapter 8. Long-Term Strategy ..............................................................................................132 

8.1 Overview ...................................................................................................................132 

8.1.1 Summary of all Anthropogenic Sources of Visibility Impairment 

 Considered in Developing the Long-Term Strategy ..................................132 

8.1.2 Summary of Interstate Transport and Contribution ...................................132 

8.1.2.1 Other States’ Class I Areas Affected by Wyoming Emissions ...132 

8.1.2.2 Wyoming Class I Areas Affected by Other States, Nations 

 and Areas of the World ..............................................................135 

8.1.3 Summary of Interstate Consultation ..........................................................138 

8.1.4 Estimated International and Global Contribution to Wyoming 

 Class I Areas .............................................................................................138 

8.2 Required Factors for the Long-Term Strategy ..........................................................141 

8.2.1 Emission Reductions Due to Ongoing Air Pollution Control Programs ...141 

8.2.1.1 New Source Review Program .....................................................141 

8.2.1.1.1 Prevention of Significant Deterioration (PSD) 

 Program ........................................................................141 

8.2.1.1.2 Minor Source BACT Program .....................................142 

8.2.1.2 Title V Operating Permit Program ..............................................142 

8.2.1.3 New Source Performance Standards (NSPS) .............................143 

8.2.1.4 MACT - HAPs Program .............................................................150 

8.2.1.5 Phase I Visibility Rules - Wyoming Reasonably Attributable 

 Visibility Impairment Rules ........................................................160 

8.2.1.6 Ongoing Implementation of Federal Mobile Source 

 Regulations .................................................................................160 

8.2.1.7 Ongoing Implementation of Programs to Meet PM10 NAAQS ..161 

8.2.1.7.1 Nonattainment SIP (PM10) - City of Sheridan .............161 

8.2.1.7.2 Natural and Uncontrollable Sources Program - Natural

 Events Action Plan .......................................................162 

8.2.2 Measures to Mitigate the Impacts of Construction Activities ...................163 

8.2.3 Emission Limitations and Schedules of Compliance ................................163 

8.2.4 Source Retirement and Replacement Schedules ........................................163 

8.2.5 Agricultural and Forestry Smoke Management Techniques .....................164 

8.2.6 Enforceability of Wyoming’s Measures ....................................................165 

8.3 Additional Measures in the Long-Term Strategy .....................................................166 

8.3.1 Future Federal Mobile Programs ...............................................................166 

8.3.2 Efforts to Address Offshore Shipping........................................................167 

8.3.3 Long-Term Control Strategies for BART Facilities ..................................168 
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8.3.4 Evaluation of Control Strategies for Sources Identified in the 

 Reasonable Progress - Four-Factor Analysis .............................................169 

8.3.5 Oil and Gas ................................................................................................169 

8.3.6 Projection of the Net Effect on Visibility ..................................................170 

Chapter 9. Ongoing Monitoring and Emission Inventory Strategy .....................................178 

Chapter 10. Comprehensive Periodic Implementation Plan Revisions ...............................181 

Chapter 11. Wyoming Regional Haze SIP Development and Consultation Process ..........182 

11.1 State to State Consultation ......................................................................................182 

11.2 State and Federal Land Manager Coordination ......................................................185 

11.3 Tribal Consultation .................................................................................................186 

Chapter 12. Determination of the Adequacy of the Existing Plan .......................................187 

Chapter 13. Technical Information and Data Relied Upon in This Plan ............................188 

13.1 The WRAP and Technical Support .........................................................................188 

13.2 WRAP Committees and Work Groups ...................................................................188 

13.3 WRAP Forums ........................................................................................................191 

13.4 WRAP TSS .............................................................................................................193 

13.5 IMPROVE Monitoring ...........................................................................................193 

13.5.1 Background on IMPROVE Monitoring ...................................................193 

13.6 Formula for Reconstructed Light Extinction ..........................................................194 

13.7 Wyoming IMPROVE Monitoring Network ...........................................................196 

List of Tables

Table 3-1. IMPROVE Monitor Aerosol Composition ..................................................................30 

Table 4.2-1. Wyoming SOx Emission Inventory - 2002 and 2018 ...............................................41 

Table 4.3-1. Wyoming NOx Emission Inventory - 2002 and 2018 ..............................................42 

Table 4.4-1. Wyoming OC Emission Inventory - 2002 and 2018 ................................................43 

Table 4.5-1. Wyoming EC Emission Inventory - 2002 and 2018 ................................................44 

Table 4.6-1. Wyoming Fine PM Emission Inventory - 2002 and 2018 ........................................45 

Table 4.7-1. Wyoming Coarse PM Emission Inventory - 2002 and 2018 ....................................46 

Table 4.8-1. Wyoming Ammonia Emission Inventory - 2002 and 2018......................................47 

Table 4.9-1. Net Change From PRP18a to PRP18b Emission Inventories .................................48 

Table 5.3-1. CMAQ Modeling Results for 20% Worst Days and 20% Best Days for 

 Wyoming Class I Areas ...........................................................................................85 

Table 5.3.1-1. Pollutant Breakdown on 20% Worst Days for Yellowstone NP, Grand 

 Teton NP, and Teton Wilderness Area ..................................................................86 

Table 5.3.1-2. Pollutant Breakdown on 20% Worst Days for North Absaroka and 

 Washakie Wilderness Area ....................................................................................87 
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Table 5.3.1-3. Pollutant Breakdown on 20% Worst Days for Bridger and Fitzpatrick 

 Wilderness Areas ...................................................................................................88 

Table 6.2-1. Regional Sulfur Dioxide Emissions and Milestone Report Summary .....................90 

Table 6.2-2. Visibility - Sulfate Extinction Only ..........................................................................91 

Table 6.4-1. BART Determinations for Wyoming Sources .........................................................94 

Table 7.2-1. 20% Best and Worst Days Baseline, Natural Conditions, and Uniform Rate 

 of Progress Goal for Wyoming Class I Areas ........................................................115 

Table 7.3.3-1. Estimated Costs of Potential Emission Control Devices for Two Boilers

 at the Dave Johnston Electric Generation Station................................................119 

Table 7.3.3-2. Estimated Energy and Non-Air Environmental Impacts of Potential

 Emission Control Devices for Two Boilers at the Dave Johnston Electric 

 Generating Station ..............................................................................................120 

Table 7.3.4-1. Estimated Costs of Potential Emission Control Devices for One Cement

 Kiln at the Mountain Cement Company, Laramie Plant.....................................121 

Table 7.3.4-2. Estimated Energy and Non-Air Environmental Impacts of Potential Emission

 Control Devices for Kiln #2 at the Mountain Cement Company, Laramie 

 Plant ....................................................................................................................123 

Table 7.3.5-1. Estimated Costs for Oil and Gas Exploration and Production Equipment ..........126 

Table 7.5-1. Reasonable Progress Goals for 20% Worst Days and 20% Best Days for 

 Wyoming Class I Areas ..........................................................................................128 

Table 8.1.2.1-1. Nitrate Contribution to Haze in Baseline Years ...............................................134 

Table 8.1.2.1-2. Sulfate Contribution to Haze in Baseline Years ...............................................135 

Table 8.3.6-1. Class I Area Visibility Summary for YELL2 on 20% Worst Days ....................171 

Table 8.3.6-2. Class I Area Visibility Summary for NOAB1 on 20% Worst Days ...................172 

Table 8.3.6-3. Class I Area Visibility Summary for BRID1 on 20% Worst Days .....................173 

Table 8.3.6-4. Class I Area Visibility Summary for YELL2 on 20% Best Days .......................174 

Table 8.3.6-5. Class I Area Visibility Summary for NOAB1 on 20% Best Days ......................175 

Table 8.3.6-6. Class I Area Visibility Summary for BRID1 on 20% Best Days ........................176 

Table 9-1. The Wyoming IMPROVE Monitoring Network .......................................................179 

Table 13.7-1. The Wyoming IMPROVE Monitoring Network ..................................................196 

List of Figures

Figure 2.1-1. National Parks and Wilderness Areas in Wyoming (Class I Areas) .........................3 

Figure 2.1.1-1. Mormon Row .........................................................................................................3 

Figure 2.1.1-2. Grand Teton NP Class I Boundary .........................................................................4 

Figure 2.1.2-1. Gravel Creek in 1996. Burned in giant Huck Fire of 1988 ...................................5 

Figure 2.1.2-2. Pendergraft Peak 1991 ...........................................................................................5 

Figure 2.1.2-3. Teton Wilderness Class I Boundary .......................................................................6 

Figure 2.1.3-1. Hot Pool Near Red Cone Geyser ...........................................................................7 

Figure 2.1.3-2. Yellowstone National Park Boundary ....................................................................8 

Figure 2.1.4-1. YELL2 Monitoring Site Location ..........................................................................9 

Figure 2.1.4-2. Looking South Toward the YELL2 Monitor .......................................................10 

Figure 2.1.5-1. YELL2 Monitor - Baseline Best Days .................................................................11 

Figure 2.1.5-2. YELL2 Monitor - Baseline Worst Days ..............................................................11 

Figure 2.1.5-3. YELL2 Monitor - Natural Best Days ...................................................................12 
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Figure 2.1.5-4. YELL2 Monitor - Natural Worst Days ................................................................12 

Figure 2.2.1-1. Pilot and Index Peaks ...........................................................................................13 

Figure 2.2.1-2. North Absaroka Wilderness Boundary ................................................................14 

Figure 2.2.2-1. Piney Creek With Part of Carter Mountain at Head of Canyon ...........................15 

Figure 2.2.2-2. Washakie Wilderness Class I Area Boundary .....................................................16 

Figure 2.2.3-1. NOAB1 Monitoring Site ......................................................................................17 

Figure 2.2.3-2. Looking South Toward the NOAB1 Monitor ......................................................18 

Figure 2.2.4-1. BRID1 Monitor - Baseline Best Days ..................................................................19 

Figure 2.2.4-2. BRID1 Monitor - Baseline Worst Days ...............................................................19 

Figure 2.2.4-3. BRID1 Monitor - Natural Best Days ...................................................................20 

Figure 2.2.4-4. BRID1 Monitor - Natural Worst Days .................................................................20 

Figure 2.3.1-1. Slide Lake .............................................................................................................21 

Figure 2.3.1-2. Bridger Wilderness Monitoring Site and Partial Boundary .................................22 

Figure 2.3.1-3. Bridger Wilderness Boundary ..............................................................................22 

Figure 2.3.2-1. The Wind Rivers From the Wind River Indian Reservation ................................23 

Figure 2.3.2-2. Fitzpatrick Wilderness Class I Boundary .............................................................24 

Figure 2.3.3-1. BRID1 Monitoring Site ........................................................................................25 

Figure 2.3.3-2. Looking North Toward BRID1 Monitor ..............................................................25 

Figure 2.3.4-1. BRID1 Monitor - Baseline Best Days ..................................................................27 

Figure 2.3.4-2. BRID1 Monitor - Baseline Worst Days ...............................................................27 

Figure 2.3.4-3. BRID1 Monitor - Natural Best Days ...................................................................28 

Figure 2.3.4-4. BRID1 Monitor - Natural Worst Days .................................................................28 

Figure 3-1. Light Extinction by Pollutant Species for Wyoming Class I Areas 20% Best

 Days (2000-2004) ......................................................................................................31 

Figure 3-2. Light Extinction by Pollutant Species for Wyoming Class I Areas 20% Worst 

 Days (2000-2004) ......................................................................................................32 

Figure 3.1-1. Yellowstone IMPROVE Site - Average Pollutant Species Contribution to 

 20% Best and 20% Worst Days Baseline (2000-2004) ..........................................33 

Figure 3.1-2. Yellowstone IMPROVE Site - Monthly Average Pollutant Species Variation 

 for All Days Sampled During the Baseline Period (2000-2004) ............................33 

Figure 3.1-3. Yellowstone IMPROVE Site - Pollutant Species Variation for All Days

 Sampled in 2004 .....................................................................................................34 

Figure 3.1-4. Yellowstone IMPROVE Site - Baseline Worst Day Aerosol Composition 

 Compared to Visibility Improvement Needed by 2018 & 2064 .............................34 

Figure 3.2-1. North Absaroka IMPROVE Site - Average Pollutant Species Contribution to 

 20% Best and 20% Worst Days Baseline (2000-2004) ..........................................35 

Figure 3.2-2. North Absaroka IMPROVE Site - Monthly Average Pollutant Species

 Variation for All Days Sampled During the Baseline Period (2000-2004) ............36 

Figure 3.2-3. North Absaroka IMPROVE Site - Pollutant Species Variation for All Days

 Sampled in 2004 .....................................................................................................36 

Figure 3.2-4. North Absaroka IMPROVE Site - Baseline Worst Day Aerosol Composition 

 Compared to Visibility Improvement Needed by 2018 & 2064 .............................37 

Figure 3.3-1. Bridger IMPROVE Site - Average Pollutant Species Contribution to 20% 

 Best and 20% Worst Days Baseline (2000-2004)...................................................38 

Figure 3.3-2. Bridger IMPROVE Site - Monthly Average Pollutant Species Variation for 

 All Days Sampled During the Baseline Period (2000-2004) ..................................38 
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Figure 3.3-3. Bridger IMPROVE Site - Pollutant Species Variation for All Days Sampled

 in 2004 ....................................................................................................................39 

Figure 3.3-4. Bridger IMPROVE Site - Baseline Worst Day Aerosol Composition 

 Compared to Visibility Improvement Needed by 2018 & 2064 .............................39 

Figure 5.2.1-1. PSAT Sulfate Contribution at Yellowstone NP, Grand Teton NP, and Teton 

 Wilderness on 20% Worst Visibility Days ...........................................................55 

Figure 5.2.1-2. PSAT Sulfate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Worst Visibility Days .................................................56 

Figure 5.2.1-3. PSAT Sulfate Contribution at Bridger Wilderness and Fitzpatrick Wilderness

 Areas on 20% Worst Visibility Days ....................................................................57 

Figure 5.2.2-1. PSAT Sulfate Contribution at Yellowstone NP, Grand Teton NP, and Teton 

 Wilderness Area on 20% Best Visibility Days .....................................................59 

Figure 5.2.2-2. PSAT Sulfate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Best Visibility Days ...................................................60 

Figure 5.2.2-3. PSAT Sulfate Contribution at Bridger Wilderness and Fitzpatrick Wilderness

 Areas on 20% Best Visibility Days ......................................................................61 

Figure 5.2.3-1. PSAT Nitrate Contribution at Yellowstone NP, Grand Teton NP, and Teton

 Wilderness Area on 20% Worst Visibility Days ..................................................62 

Figure 5.2.3-2. PSAT Nitrate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Worst Visibility Days .................................................63 

Figure 5.2.3-3. PSAT Nitrate Contribution at Bridger Wilderness and Fitzpatrick Wilderness

 Areas on 20% Worst Visibility Days ....................................................................64 

Figure 5.2.4-1. PSAT Nitrate Contribution at Yellowstone NP, Grand Teton NP, and Teton 

 Wilderness Area on 20% Best Visibility Days .....................................................65 

Figure 5.2.4-2. PSAT Nitrate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Best Visibility Days ...................................................66 

Figure 5.2.4-3. PSAT Nitrate Contribution at Bridger Wilderness and Fitzpatrick Wilderness 

 Areas on 20% Best Visibility Days ......................................................................67 

Figure 5.2.5-1. WEP Potential Contribution to OC at Yellowstone NP, Grand Teton NP, and 

 Teton Wilderness Area on 20% Worst Visibility Days .......................................68 

Figure 5.2.5-2. WEP Potential Contribution to OC at North Absaroka Wilderness and 

 Washakie Wilderness Areas on 20% Worst Visibility Days ...............................69 

Figure 5.2.5-3. WEP Potential Contribution to OC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Worst Visibility Days ................................................69 

Figure 5.2.6-1. WEP Potential Contribution to OC at Yellowstone NP, Grand Teton NP, and 

 Teton Wilderness Area on 20% Best Visibility Days ..........................................70 

Figure 5.2.6-2. WEP Potential Contribution to OC at North Absaroka Wilderness and

 Washakie Wilderness Areas on 20% Best Visibility Days ..................................71 

Figure 5.2.6-3. WEP Potential Contribution to OC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Best Visibility Days ..................................................71 

Figure 5.2.7-1. WEP Potential Contribution to EC at Yellowstone NP, Grand Teton NP, and 

 Teton Wilderness Area on 20% Worst Visibility Days .......................................72 

Figure 5.2.7-2. WEP Potential Contribution to EC at North Absaroka Wilderness and 

 Washakie Wilderness Areas on 20% Worst Visibility Days ...............................73 

Figure 5.2.7-3. WEP Potential Contribution to EC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Worst Visibility Days ................................................73 
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Figure 5.2.8-1. WEP Potential Contribution to EC at Yellowstone NP, Grand Teton NP, and 

 Teton Wilderness Area on 20% Best Visibility Days ..........................................74 

Figure 5.2.8-2. WEP Potential Contribution to EC at North Absaroka Wilderness and

 Washakie Wilderness Areas on 20% Best Visibility Days ..................................75 

Figure 5.2.8-3. WEP Potential Contribution to EC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Best Visibility Days ..................................................75 

Figure 5.2.9-1. WEP Potential Contribution to Fine PM at Yellowstone NP, Grand Teton 

 NP, and Teton Wilderness Area on 20% Worst Visibility Days .........................76 

Figure 5.2.9-2. WEP Potential Contribution to Fine PM at North Absaroka Wilderness and

 Washakie Wilderness Areas on 20% Worst Visibility Days ...............................77 

Figure 5.2.9-3. WEP Potential Contribution to Fine PM at Bridger Wilderness and

 Fitzpatrick Wilderness Areas on 20% Worst visibility Days ..............................77 

Figure 5.2.10-1. WEP Potential Contribution to Fine PM at Yellowstone NP, Grand Teton 

 NP, and Teton Wilderness Area on 20% Best Visibility Days ..........................78 

Figure 5.2.10-2. WEP Potential Contribution to Fine PM at North Absaroka Wilderness and

 Washakie Wilderness Areas on 20% Best Visibility Days ................................79 

Figure 5.2.10-3. WEP Potential Contribution to Fine PM at Bridger Wilderness and

 Fitzpatrick Wilderness Areas on 20% Best Visibility Days ..............................79 

Figure 5.2.11-1. WEP Potential Contribution to Coarse PM at Yellowstone NP, Grand Teton 

 NP, and Teton Wilderness Area on 20% Worst Visibility Days .......................80 

Figure 5.2.11-2. WEP Potential Contribution to Coarse PM at North Absaroka Wilderness 

 and Washakie Wilderness Areas on 20% Worst Visibility Days ......................81 

Figure 5.2.11-3. WEP Potential Contribution to Coarse PM at Bridger Wilderness and

 Fitzpatrick Wilderness Areas on 20% Worst Visibility Days ...........................81 

Figure 5.2.12-1. WEP Potential Contribution to Coarse PM at Yellowstone NP, Grand Teton 

 NP, and Teton Wilderness Area on 20% Best Visibility Days ..........................82 

Figure 5.2.12-2. WEP Potential Contribution to Coarse PM at North Absaroka Wilderness 

 and Washakie Wilderness Areas on 20% Best Visibility Days .........................83 

Figure 5.2.12-3. WEP Potential Contribution to Coarse PM at Bridger Wilderness and

 Fitzpatrick Wilderness Areas on 20% Best Visibility Days ..............................84 

Figure 5.3.1-1. Glide Slope by Pollutant on 20% Worst Days for Yellowstone NP, 

 Grand Teton NP, and Teton Wilderness Area .....................................................86 

Figure 5.3.1-2. Glide Slope by Pollutant on 20% Worst Days for North Absaroka and 

 Washakie Wilderness Areas ................................................................................87 

Figure 5.3.1-3. Glide Slope by Pollutant on 20% Worst Days for Bridger and Fitzpatrick 

 Wilderness Areas .................................................................................................88 

Figure 6.5.8-1. Additional Cumulative NOx Reductions From Wyoming BART Sources ........112 

Figure 7.6-1. Time Series Plot by Pollutant on 20% Worst Days for Yellowstone NP, 

 Grand Teton NP, and Teton Wilderness Area ......................................................130 

Figure 7.6-2. Time Series Plot by Pollutant on 20% Worst Days for North Absaroka 

 Wilderness and Washakie Wilderness Areas ........................................................131 

Figure 7.6-3. Time Series Plot by Pollutant on 20% Worst Days for Bridger and Fitzpatrick 

 Wilderness Areas ..................................................................................................131 

Figure 8.1.2.1-1. Wyoming, South Dakota, Montana, Idaho, Utah, Colorado and North 

 Dakota Class I Areas .......................................................................................133 

Figure 8.3.6-7. Additional Cumulative NOx Reductions From Wyoming Sources....................177 
ix

Figure 9-1. Links to Site Locations and Monitors ......................................................................179 

Figure 11.1-1. Regional Planning Organizations ........................................................................185 

Figure 13.5.1-1. Schematic of the IMPROVE Sampler Showing the Four Modules 

 With Separate Inlets and Pumps .......................................................................194 
1 

CHAPTER 1

GENERAL PLAN PROVISIONS

Section 169A of the Clean Air Act establishes a national goal for protecting visibility in 

Federally-protected scenic areas. These Class I areas include national parks and wilderness 

areas. Regional haze is a type of visibility impairment caused by air pollutants emitted by 

numerous sources across a broad region. On July 1, 1999, the Environmental Protection Agency 

(EPA) issued regional haze rules to comply with requirements of the Clean Air Act. Under 40 

CFR 51.308, the rule requires the State of Wyoming to develop State Implementation Plans 

(SIPs) which include visibility progress goals for each of the seven Class I areas in Wyoming, as 

well as emission reduction strategies and other measures to meet these goals. Under 40 CFR 

51.309, the rule also provided an optional approach to Wyoming and eight other western states to 

incorporate emission reduction strategies issued by the Grand Canyon Visibility Transport 

Commission (GCVTC) designed primarily to improve visibility in 16 Class I areas on the 

Colorado Plateau. 

On December 29, 2003, the State of Wyoming submitted a visibility SIP to meet the 

requirements of 40 CFR 51.309. The 2003 309 SIP and subsequent revisions to the 309 SIP 

address the first phase of requirements, with an emphasis on stationary source SO2 emission 

reductions and a focus on improving visibility on the Colorado Plateau. In the 2003 submittal, 

Wyoming committed to addressing the next phase of visibility requirements and additional 

visibility improvement in Wyoming’s seven Class I areas by means of a State Implementation 

Plan meeting the requirements in 309(g). 

Since the 2003 submittal of the 309 SIP, EPA has revised both 40 CFR 51.308 and 309 in 

response to numerous judicial challenges. As a result of revisions to the Federal rules, the State 

of Wyoming submitted revisions to the December 29, 2003, 309 SIP under separate cover, on 

November 21, 2008. 

This 309(g) SIP submission serves as a supplement to the 309 SIP submittal. Pursuant to the 

requirements of 51.309(g), the State of Wyoming submits this Plan with: a demonstration of 

expected visibility conditions for the most impaired and least impaired days at the additional 

mandatory Class I areas; provisions for establishing reasonable progress goals for Wyoming’s 

seven Class I areas complying with 51.308(d)(1)-(4); long-term strategies that build upon 

emission reduction strategies developed in the first 309 SIP submittal; and finally provisions to 

address long-term strategies and Best Available Retrofit Technology (BART) requirements for 

stationary source Particulate Matter (PM) and Nitrogen Oxide (NOx) emissions pursuant to 

51.308(e). 

The State of Wyoming commits to participate in a Regional Planning Process with Alaska, 

Arizona, California, Colorado, Idaho, Montana, New Mexico, North Dakota, Oregon, South 

Dakota, Utah, and Washington, and commits to continue participation through future SIPs. The 

Regional Planning Process describes the process, goals, objectives, management and decision 

making structure, deadlines for completing significant technical analyses and developing 

emission management strategies and a regulation implementing the recommendations of the 

regional group. All Western Regional Air Partnership (WRAP) Work Plans and the WRAP 
2 

2008-2012 Strategic Plan, which document the Regional Planning Process, are contained in

Chapter 1 of the Wyoming Technical Support Document (TSD). 

Pursuant to the Tribal Authority Rule, any Tribe whose lands are surrounded by the State of 

Wyoming have the option to develop a regional haze TIP for their lands to assure reasonable 

progress in the seven Class I areas in Wyoming. As such, no provisions of this Implementation 

Plan shall be construed as being applicable to Indian Country. 
3 

CHAPTER 2

WYOMING CLASS I AREAS; BASELINE, NATURAL AND

CURRENT VISIBILITY CONDITIONS

2.1 Description of the Yellowstone Monitoring Site (YELL2) Class I Areas

The monitoring site designated as “YELL2” is the representative regional haze monitoring 

station for three Wyoming Class I areas (Grand Teton National Park, Yellowstone National Park 

and Teton Wilderness). Each of these Class I areas are described below.

Figure 2.1-1. National Parks and Wilderness Areas in Wyoming (Class I Areas)

(http://www.coha.dri.edu/web/state_analysis/Wyoming/Wyoming.html) 

2.1.1 Grand Teton National Park 

Figure 2.1.1-1. Mormon Row (Courtesy of National Park Service)
4 

Grand Teton National Park occupies 309,995 acres along the Teton Range and adjacent Jackson 

Lake. The Teton Range borders the west side of the National Park, with elevations exceeding 

12,000 feet, and 13,770 feet at the summit of the Grand Teton. The Teton Range, a 40-mile-long 

mountain front, was formed from earthquakes that occurred over the past 13 million years along 

a fault line. The eastern half of the Park consists of Jackson Lake and valley of the upper Snake 

River. Where the Snake River exits the Park at the south boundary, the elevation is the lowest at 

6,800 feet. The Park is adjacent to the Teton Wilderness to the northeast and is 6 miles south of 

Yellowstone National Park and the headwaters of the Snake River (Figure 2.1-1). Seven glacial 

lakes lie at the base of the range, while over 100 alpine lakes can be found in the backcountry. 

Elk, moose, mule deer, bison, pronghorn and black bears can be found in the Park. Grizzlies can 

also be found, but are located in more remote areas. Over 300 species of birds, including bald 

eagles, peregrine falcons and trumpeter swans can be observed in the Park. 

Figure 2.1.1-2. Grand Teton NP Class I Boundary

(http://www.coha.dri.edu/images/clipart/wy_20km_terrain_grandteton.jpg) 
5 

2.1.2 Teton Wilderness

Figure 2.1.2-1. Gravel Creek in 1996. Burned in giant Huck Fire of 1988. (Courtesy of Ralph Maughan)

(http://www.forwolves.org/ralph/wpages/tetonwld.htm) 

Figure 2.1.2-2. Pendergraft Peak 1991 (Courtesy of U.S. Forest Service)

(http://www.fsvisimages.com/gallery/TETO/start.htm) 

The Teton Wilderness encompasses 585,468 acres which straddle the Continental Divide in 

western Wyoming. It is bordered by Yellowstone National Park to the north, Grand Teton 

National Park to the west, and the Washakie Wilderness to the east (Figure 2.1-1). Elevations 
6 

range from 7,500 to 9,675 feet west of the Continental Divide, while east of the Continental 

Divide elevations are generally higher with the summit of Younts Peak reaching 12,165 feet. At 

Two Ocean Pass, Two Ocean Creek straddles the Continental Divide, sending waters to both the 

Atlantic and the Pacific Oceans. As with Grand Teton National Park, elk, moose, mule deer, 

bison, pronghorn and black bears can be found in the Teton Wilderness. Bighorn sheep, 

mountain lions, wolves, grizzlies and at least 75 other mammal species are also found here, as 

well as over 300 species of birds and 30 species of fish. 

Figure 2.1.2-3. Teton Wilderness Class I Boundary

(http://www.coha.dri.edu/images/clipart/wy_20km_terrain_teton.jpg) 
7 

2.1.3 Yellowstone National Park

Figure 2.1.3-1. Hot Pool Near Red Cone Geyser (Courtesy National Park Service)

(http://www.nps.gov/archive/yell/slidefile/thermalfeatures/hotspringsterraces/others/Images/06202.jpg)

Yellowstone National Park became the world’s first national park on March 1, 1872, and 

occupies 2,221,766 acres in northwestern Wyoming, overlapping into Montana and Idaho 

(Figure 2.1-1). The highest elevation is 11,358 feet at the summit of Eagle Peak on the 

southeastern Park boundary, while the lowest elevations (5,314 feet) are found where the 

Yellowstone River exits the Park on the north boundary. Yellowstone Lake is the largest highaltitude lake in North America and is centered over the Yellowstone Caldera, the largest 

supervolcano on the continent. The caldera, considered an active volcano, has erupted several 

times in the last two million years. Fifty percent of the world’s geothermal features are in 

Yellowstone, fueled by this ongoing volcanic activity. Wildlife abounds in the Park, with the 

more common species being elk, bison, grizzlies and wolves. In 2007, approximately 3,151,373 

people visited Yellowstone National Park, bringing the total number of visitors to over 

142,681,000 since the park opened in 1872. 
8 

Figure 2.1.3-2. Yellowstone National Park Boundary (Courtesy of National Park Service)

(http://www.nps.gov/carto/PDF/YELLmap2.pdf) 

2.1.4 Monitoring Strategy and Location - YELL2 Monitoring Site

The IMPROVE site designated as the monitor representing Grand Teton National Park, Teton 

Wilderness and Yellowstone National Park is YELL2. The Wyoming Department of 

Environmental Quality, Air Quality Division (the Division), considers the YELL2 site as 

adequate for assessing reasonable progress goals of the three above-mentioned Class I areas and 

no additional monitoring sites or equipment are necessary at this time.

The Air Quality Division routinely participates in the IMPROVE monitoring program by 

attending Western States Air Resources Council (WESTAR) and Western Regional Air 

Partnership (WRAP) meetings and maintaining memberships in both organizations. 
9 

YELL2 is located in central Yellowstone National Park near the north shore of Yellowstone 

Lake. It is 37 miles north of Grand Teton National Park, across the Continental headwaters 

divide between the Yellowstone River and Snake River watersheds. YELL2 is 30 miles north 

and west of the nearest Teton Wilderness boundary. The YELL2 site elevation is 7,954 feet, 

which is 220 feet above Yellowstone Lake. 

The nearest metropolitan area to the YELL2 monitor, Billings, Montana (over 149,650 

population), is situated approximately 124 miles northeast of the monitor. The metropolitan area 

of Boise, Idaho (over 635,450 population) lies approximately 295 miles to the southwest of the 

monitor and the metropolitan area of Salt Lake City, Utah (over 1,099,000) is located 

approximately 273 miles to the southwest. 

Figure 2.1.4-1. YELL2 Monitoring Site Location

(http://www.coha.dri.edu/images/clipart/wy_20km_terrain_yellowstone.jpg) 

YELL2

Yellowstone Lake
10

Figure 2.1.4-2. Looking South Toward the YELL2 Monitor

(http://vista.cira.colostate.edu/views/Web/SiteBrowser/SiteBrowser.aspx) 

2.1.5 Assessment of Baseline, Natural and Current Conditions - YELL2 Class I Areas

Natural visibility represents the visibility condition that would be experienced in the absence of 

human-caused impairment. Based on EPA guidance, Grand Teton National Park, Teton 

Wilderness and Yellowstone National Park Class I areas have an established natural visibility of 

0.43 deciviews for the 20 percent best days and 6.44 deciviews for the 20 percent worst days. 

This is based on on-site data at the YELL2 IMPROVE monitoring site. 

Baseline visibility is determined from the YELL2 monitoring site (located in central Yellowstone 

Park) for the 20 percent best and 20 percent worst days for the years 2000 through 2004 as 

specified in the Regional Haze regulations under 40 CFR 51.308(d)(2)(i). The baseline visibility 

for Grand Teton National Park, Teton Wilderness and Yellowstone National Park Class I areas is

2.58 deciviews for the 20 percent best days and 11.76 deciviews for the 20 percent worst days, 

which, for this first SIP submittal, is also the same as the current visibility. These best and worst 

20 percent conditions are also calculated based on EPA guidance. This technical information 

was obtained from the “Haze Planning” section of the Western Regional Air Partnership 

(WRAP) Technical Support System (TSS) by choosing the “Monitoring” section followed by the 

“Deciview Glide Slope” information at http://vista.cira.colostate.edu/tss/. Further description of 

this technical information can be found in Chapter 13. 

Photographs representing similar visibility conditions on best and worst days for baseline and 

natural conditions are included in Figures 2.1.5-1 through 2.1.5-4. 
11

Figure 2.1.5-1. YELL2 Monitor - Baseline Best Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/YELL/start.htm

Figure 2.1.5-2. YELL2 Monitor - Baseline Worst Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/YELL/start.htm

Baseline Best Days

Vista Reference: Avalanche Peak

(Yellowstone National Park)

Photo Taken at 9:00 AM

Haze Index (HI) = 3 Deciviews

Bext = 14 Mm-1

Visual Range = 280 km/174 mi

Baseline Worst Days

Vista Reference: Avalanche Peak

(Yellowstone National Park)

Photo Taken at 9:00 AM

Haze Index (HI) = 12 Deciviews

Bext = 33 Mm-1

Visual Range = 120 km/75 mi
12

Figure 2.1.5-3. YELL2 Monitor - Natural Best Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/YELL/start.htm

Figure 2.1.5-4. YELL2 Monitor - Natural Worst Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/YELL/start.htm

Natural Best Days

Vista Reference: Avalanche Peak

(Yellowstone National Park)

Photo Taken at 9:00 AM

Haze Index (HI) = 0 Deciview

Bext = 10 Mm-1

Visual Range = 390 km/242 mi

Natural Worst Days

Vista Reference: Avalanche Peak

(Yellowstone National Park)

Photo Taken at 9:00 AM

Haze Index (HI) = 6 Deciviews

Bext = 18 Mm-1

Visual Range = 220 km/137 mi
13

2.2 Description of the North Absaroka Monitoring Site (NOAB1) Class I Areas 

The monitoring site designated as “NOAB1” is the representative regional haze monitoring 

station for two Wyoming Class I areas (North Absaroka Wilderness and Washakie Wilderness). 

Each of these Class I areas are described below.

2.2.1 North Absaroka Wilderness

Figure 2.2.1-1. Pilot and Index Peaks (Courtesy of Wikipedia and National Park Service) 

(http://commons.wikimedia.org/wiki/User:MONGO/Public_Domain_Images) 

The North Absaroka Wilderness is part of the Greater Yellowstone Area of northwestern 

Wyoming, located along the northeastern boundary of Yellowstone National Park, east of the 

Continental Divide, and occupies 350,488 acres (Figure 2.1-1). Elevations range from 

approximately 7,200 feet to more than 10,000 feet on several summits, with the highest elevation 

being 12, 216 feet on Dead Indian Peak. The terrain is very rugged and mountainous and 

dissected by numerous creeks. Only a few lakes exist, but the streams contain cutthroat, brown, 

brook, and rainbow trout. The wilderness is home to grizzly bears, and big-game hunters come 

by the hundreds for bighorn sheep, elk, and moose. Marmots and pikas dominate many of the 

talus slopes. 
14

Figure 2.2.1-2. North Absaroka Wilderness Boundary

http://www.publiclands.org/explore/quadrant_map.php?id=1560&site_name=North%20Absaroka%20Wilderness&

quad=WY_Q2&PHPSESSID=23cfeb7c9
15

2.2.2 Washakie Wilderness

 Figure 2.2.2-1. Piney Creek With Part of Carter Mountain at Head of Canyon (Courtesy 

 of Ralph Maughan)

 (http://www.forwolves.org/ralph/wpages/washakie.htm)

The Washakie Wilderness Area encompasses 704,529 acres around the headwaters of the South 

Fork of the Shoshone River in northwestern Wyoming. It is bordered on the west by the Teton 

Wilderness and Yellowstone National Park, and the North Absaroka Wilderness Area lies to the 

north across the North Fork of the Shoshone River (Figure 2.1-1). Elevations range from 

approximately 6,000 feet to 13,153 feet (Francs Peak) on the eastern boundary. Terrain is 

rugged and difficult to maneuver in many areas of this wilderness. Wildlife is bountiful, with 

mule deer, white-tailed deer, moose, elk, grizzly and black bear, pronghorns and bighorn sheep 

being some of the more common species. This area has fewer lakes than some of the other areas, 

so fishing opportunities are more limited. However, there are several streams and rivers which 

do support trout. 
16

Figure 2.2.2-2. Washakie Wilderness Class I Area Boundary

(http://www.coha.dri.edu/images/clipart/wy_20km_terrain_washakie.jpg) 

2.2.3 Monitoring Strategy and Location - NOAB1 Monitoring Site

The IMPROVE site designated as the monitor representing the North Absaroka and Washakie 

Wilderness Areas is NOAB1. Collection of data at the NOAB1 monitoring site is subsidized by 

the Wyoming Department of Environmental Quality. The Division considers the NOAB1 site as 

adequate for assessing reasonable progress goals of the two above-mentioned Class I areas and 

no additional monitoring sites or equipment are necessary at this time.

The Air Quality Division routinely participates in the IMPROVE monitoring program by 

attending Western States Air Resources Council (WESTAR) and Western Regional Air 

Partnership (WRAP) meetings and maintaining memberships in both organizations. 

NOAB1 is located in Dead Indian Pass, approximately 25 miles northwest of Cody, Wyoming 

and about 3 miles northeast of the closest North Absaroka Wilderness Area boundary. It is 25 

miles north of the Washakie Wilderness boundary. The NOAB1 monitoring site elevation is 

8,134 feet, which is 538 feet below the summit of Dead Indian Hill to the northeast and 66 feet 

above Dead Indian Pass and State Highway SR 296. 

The nearest metropolitan area to the NOAB1 monitor, Billings, Montana (over 149,650 

population), is situated approximately 83 miles northeast of the monitor. The metropolitan area 

of Boise, Idaho (over 635,450 population) lies approximately 348 miles to the southwest of the 
17

monitor and the metropolitan area of Salt Lake City, Utah (over 1,099,000) is located 

approximately 301 miles to the southwest. 

Figure 2.2.3-1. NOAB1 Monitoring Site

http://www.coha.dri.edu/images/clipart/wy_20km_terrain_northabsaroka.jpg
18

Figure 2.2.3-2. Looking South Toward the NOAB1 Monitor

(http://vista.cira.colostate.edu/views/Web/SiteBrowser/SiteBrowser.aspx) 

2.2.4 Assessment of Baseline, Natural and Current Conditions - NOAB1 Class I Areas 

Natural visibility represents the visibility condition that would be experienced in the absence of 

human-caused impairment. Based on EPA guidance, the North Absaroka Wilderness and 

Washakie Wilderness Class I areas have an established natural visibility of 0.58 deciviews for 

the 20 percent best days and 6.83 deciviews for the 20 percent worst days. This is based on onsite data at the NOAB1 IMPROVE monitoring site.

 

Baseline visibility is determined from the NOAB1 monitoring site (located in Dead Indian Pass, 

about 25 miles northwest of Cody, Wyoming) for the 20 percent best and 20 percent worst days 

for the years 2002 through 2004 as specified in the Regional Haze regulations under 40 CFR 

51.308(d)(2)(i). The baseline visibility for the North Absaroka and Washakie Wilderness Class I 

areas is 2.02 deciviews for the 20 percent best days and 11.45 deciviews for the 20 percent worst 

days, which, for this first SIP submittal, is also the same as the current visibility. These best and 

worst 20 percent conditions are also calculated based on EPA guidance. This technical 

information was obtained from the “Haze Planning” section of the Western Regional Air 

Partnership (WRAP) Technical Support System (TSS) by choosing the “Monitoring” section 

followed by the “Deciview Glide Slope” information at http://vista.cira.colostate.edu/tss/. 

Further description of this technical information can be found in Chapter 13. 

The historic visibility photo record is limited and does not include the North Absaroka or 

Washakie Wilderness areas. Photos depicting similar visibility scenarios from the Bridger 

Wilderness (Mt. Bonneville) have been substituted as Figures 2.2.4-1 through 2.2.4-4 for the 

baseline and natural conditions on the best and worst days. 
19

Figure 2.2.4-1. BRID1 Monitor - Baseline Best Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Figure 2.2.4-2. BRID1 Monitor - Baseline Worst Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Baseline Best Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 9:00 AM

Haze Index (HI) = 2 Deciviews

Bext = 12 Mm-1

Visual Range = 330 km/205 mi

Baseline Worst Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 9:00 AM

Haze Index (HI) = 11 Deciviews

Bext = 30 Mm-1

Visual Range = 130 km/81 mi
20

Figure 2.2.4-3. BRID1 Monitor - Natural Best Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Figure 2.2.4-4. BRID1 Monitor - Natural Worst Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Natural Best Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 9:00 AM

Haze Index (HI) = 1 Deciview

Bext = 11 Mm-1

Visual Range = 350 km/217 mi

Natural Worst Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 9:00 AM

Haze Index (HI) = 7 Deciviews

Bext = 20 Mm-1

Visual Range = 200 km/124 mi
21

2.3 Description of the Bridger Monitoring Site (BRID1) Class I Areas

The monitoring site designated as “BRID1” is the representative regional haze monitoring station 

for two Wyoming Class I areas (Bridger Wilderness and Fitzpatrick Wilderness). Each of these 

Class I areas are described below.

2.3.1 Bridger Wilderness

Figure 2.3.1-1. Slide Lake (Photo Courtesy of Ralph Maughan)

(http://www.forwolves.org/ralph/wpages/bridger.htm) 

The Bridger Wilderness, consisting of 428,169 acres, is situated on the west slope of the Wind 

River Range in Wyoming and extends approximately 80 miles along the western slope of the 

Continental Divide. The wilderness lies south of the other six Class I areas and is on the west 

border of the Fitzpatrick Wilderness (Figure 2.1-1). The Bridger Wilderness is a combination of 

jagged granite rock, alpine forest and open alpine meadows and is the headwaters for the Green 

River. This wilderness forms a triple divide for three major watersheds: the Columbia River, the 

Colorado River, and the Missouri River. The Wind River Range contains numerous peaks, some 

exceeding 13,000 feet, the highest of which is Gannett Peak (13,804 feet) located on the 

boundary between the Bridger Wilderness and the adjacent Fitzpatrick Wilderness to the east. 

This wilderness contains seven of the ten largest glaciers in the U.S. (lower 48). Some of the 

more common species found in the Bridger Wilderness are mule deer, moose, elk, bighorn sheep, 

gray wolf, and both grizzly and black bear. 
22

Figure 2.3.1-2. Bridger Wilderness Monitoring Site and Partial Boundary

http://www.coha.dri.edu/images/clipart/wy_20km_terrain_bridger.jpg

Figure 2.3.1-3. Bridger Wilderness Boundary

http://www.publiclands.org/explore/quadrant_map.php?id=1742&site_name=Bridger%20Wilderness&quad=WY_Q

8
23

2.3.2 Fitzpatrick Wilderness

Figure 2.3.2-1. The Wind Rivers From the Wind River Indian Reservation (Courtesy of Ralph Maughan)

http://www.forwolves.org/ralph/wpages/graphics/fitzpatrick1.jpg

The Fitzpatrick Wilderness Area (191,103 acres) is located on the east slope of the northern 

Wind River Range in Wyoming along the Continental Divide, which makes up its western 

border. It shares its western border with the Bridger Wilderness Area, while its eastern border is 

shared with the Wind River Indian Reservation. Elevations range from approximately 5,575 feet 

at the western side of the upper Wind River Basin at river level to east slope elevations of 8,200 

feet. Gannett Peak claims the highest elevation (13,804 feet) and is on the Divide boundary 

between the Fitzpatrick Wilderness and the adjacent Bridger Wilderness to the east. Precipitous 

canyons formed by glaciers from granite and limestone rock are found throughout the area. 

Alpine meadows, stands of timber and rocky plateaus are also common sights. There are more 

than 60 lakes and at least 75 miles of streams which tout excellent trout fishing. Abundant 

wildlife includes elk, mule deer, moose, bighorn sheep, black bear, bobcats and coyotes. 
24

Figure 2.3.2-2. Fitzpatrick Wilderness Class I Boundary

http://www.coha.dri.edu/images/clipart/wy_20km_terrain_fitzpatrick.jpg

2.3.3 Monitoring Strategy and Location - BRID1 Monitoring Site

The IMPROVE site designated as the monitor representing the Bridger and Fitzpatrick 

Wilderness Areas is BRID1. The Division considers the BRID1 site as adequate for assessing 

reasonable progress goals of the two above-mentioned Class I areas and no additional monitoring 

sites or equipment are necessary at this time.

The Air Quality Division routinely participates in the IMPROVE monitoring program by 

attending Western States Air Resources Council (WESTAR) and Western Regional Air 

Partnership (WRAP) meetings and maintaining memberships in both organizations. 

BRID1 is located at the White Pine Ski Area, 10 miles northeast of Pinedale, Wyoming and 

approximately 2 miles outside of the southwestern Bridger Wilderness boundary. The 

monitoring site sits on a small hilltop in a high basin on the west slope of the Wind River Range 

at an elevation of 8,553 feet. The site is approximately 1,148 feet above Fremont Lake which 

lies slightly over 1 mile to the west, and about the same distance below the elevation of the 

nearest Bridger Wilderness boundary to the northeast. BRID1 is approximately 1,378 feet higher 

than the upper Green River Basin town of Pinedale. 

The nearest metropolitan area to the BRID1 monitor, Salt Lake City, Utah (over 1,099,000), is 

located approximately 187 miles to the southwest. The metropolitan area of Billings, Montana 

(over 149,650 population), lies approximately 203 miles to the northeast of the monitor and the 
25

metropolitan area of Boise, Idaho (over 635,450 population), is situated approximately 329 miles 

southwest of the monitor. 

 Figure 2.3.3-1. BRID1 Monitoring Site

 http://www.coha.dri.edu/images/clipart/wy_20km_terrain_bridger.jpg

Figure 2.3.3-2. Looking North Toward BRID1 Monitor

http://vista.cira.colostate.edu/Images/Photos/IMPROVE/BRID1/BRID1_2005_N_IN.JPG
26

2.3.4 Assessment of Baseline, Natural and Current Conditions - BRID1 Class I Areas

Natural visibility represents the visibility condition that would be experienced in the absence of 

human-caused impairment. Based on EPA guidance, the Bridger and Fitzpatrick Wilderness 

Class I areas have an established natural visibility of 0.28 deciviews for the 20 percent best days 

and 6.45 deciviews for the 20 percent worst days. This is based on on-site data at the BRID1 

IMPROVE monitoring site.

Baseline visibility is determined from the BRID1 monitoring site (located at the White Pine Ski 

Area, 10 miles northeast of Pinedale, Wyoming) for the 20 percent best and 20 percent worst 

days for the years 2000 through 2004 as specified in the Regional Haze regulations under 40 

CFR 51.308(d)(2)(i). The baseline visibility for the Bridger and Fitzpatrick Wilderness Class I 

areas is 2.1 deciviews for the 20 percent best days and 11.12 deciviews for the 20 percent worst 

days, which, for this first SIP submittal, is also the same as the current visibility. These best and 

worst 20 percent conditions are also calculated based on EPA guidance. This technical 

information was obtained from the “Haze Planning” section of the Western Regional Air 

Partnership (WRAP) Technical Support System (TSS) by choosing the “Monitoring” section 

followed by the “Deciview Glide Slope” information at http://vista.cira.colostate.edu/tss/. 

Further description of this technical information can be found in Chapter 13. 

Photographs representing similar visibility conditions on best and worst days for baseline and 

natural conditions are included in Figures 2.3.4-1 through 2.3.4-4. 
27

Figure 2.3.4-1. BRID1 Monitor - Baseline Best Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Figure 2.3.4-2. BRID1 Monitor - Baseline Worst Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Baseline Best Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 9:00 AM

Haze Index (HI) = 2 Deciviews

Bext = 12 Mm-1

Visual Range = 330 km/205 mi

Baseline Worst Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 9:00 AM

Haze Index (HI) = 11 Deciviews

Bext = 30 Mm-1

Visual Range = 130 km/81 mi
28

Figure 2.3.4-3. BRID1 Monitor - Natural Best Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Figure 2.3.4-4. BRID1 Monitor - Natural Worst Days

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

Natural Best Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 9:00 AM

Haze Index (HI) = 1 Deciview

Bext = 11 Mm-1

Visual Range = 350 km/217 mi

Natural Worst Days

Vista Reference: Mt. Bonneville

(Bridger Wilderness)

Photo Taken at 3:00 PM

Haze Index (HI) = 6 Deciviews

Bext = 18 Mm-1

Visual Range = 220 km/137 mi
29

CHAPTER 3

POLLUTANTS CAUSING VISIBILITY IMPAIRMENT

IN WYOMING CLASS I AREAS

This chapter provides a summary of regional haze monitoring data from the IMPROVE 

monitoring sites in Wyoming, and the pollutants that affect visibility impairment in each of 

Wyoming’s Class I areas. A summary of the visibility improvement needed from baseline 

(2000-2004) to the 2018 uniform rate of progress (URP) milestone, and to the 2064 natural 

condition goal is also provided. Depictions of Wyoming IMPROVE monitoring sites are 

provided in Chapter 2. 

The haze index (HI) in deciview (dv) units, as discussed in EPA’s 2003 Guidance for Tracking 

Progress Under the Regional Haze Rule, is a visibility metric based on the light-extinction 

coefficient that expresses incremental changes in perceived visibility. A change in the HI of one 

dv is approximately equal to a 10% change in extinction coefficient. The haze index is defined 

by: 

The value of the haze index is approximately zero dv for a pristine atmosphere. This value 

increases as visibility degrades. 

EPA’s 2003 guidance for calculating light extinction is based on the original protocol defined by 

the IMPROVE program in 1988. In December 2005, the IMPROVE Steering Committee voted 

to adopt a revised algorithm for use by IMPROVE as an alternative to the original approach.

The revised algorithm for estimating light extinction is calculated as recommended for use by the 

IMPROVE steering committee using the following equations:

 bext ≈ 2.2 x fs(RH) x [Small Amm. Sulfate] + 4.8 x fL(RH) x [Large Amm. Sulfate]

 + 2.4 x fs(RH) x [Small Amm. Nitrate] + 5.1 x fL(RH) x [Large Amm. Nitrate]

 + 2.8 x [Small POM] + 6.1 x [Large POM] 

 + 10 x [EC] 

 + 1 x [Soil] 

 + 1.7 x fss(RH) x [Sea Salt]

 + 0.6 x [CM] 

 + 0.33 x [NO2(ppb)] 

 + Rayleigh Scattering (Site Specific)

The revised algorithm splits ammonium sulfate, ammonium nitrate, and POM concentrations 

into small and large size fractions as follows:
30

Chapter 13 provides additional information on light extinction. 

The following table identifies the different pollutant species that contribute to haze, and their 

abbreviations, as they appear in the figures in this section. References to sulfate and nitrate in 

this section are intended to reflect ammonium sulfate and ammonium nitrate, respectively.

 Table 3-1. IMPROVE Monitor Aerosol Composition 

Pollutant IMPROVE Abbreviation

Ammonium Nitrate ammno3f_bext 

Ammonium Sulfate ammso4f_bext 

EC (Elemental Carbon) ecf_bext

OMC (Organic Mass Carbon) omcf_bext 

CM (Coarse Mass) cm_bext

Soil (Fine Soil) soilf_bext 

Sea Salt seasalt_bext

The figures which follow in this chapter provide information for each Class I area (based on 

representative IMPROVE monitoring site) for the 20% best and 20% worst days during the 

baseline period, monthly averages of all monitored days, and the improvement needed by 2018 

and 2064. 

Figures 3-1 and 3-2 summarize the distribution of pollutant species in Wyoming’s Class I areas, 

for the current (2000-2004 baseline) 20% best and 20% worst days. 
31

Figure 3-1. Light Extinction by Pollutant Species for Wyoming Class I Areas 20% Best

 Days (2000-2004) 
32

Figure 3-2. Light Extinction by Pollutant Species for Wyoming Class I Areas 20% Worst 

 Days (2000-2004) 

As the above figures indicate, Wyoming’s Class I areas are dominated by sulfate and organic 

carbon on the 20% best days, and organic carbon and sulfate on the 20% worst days. On the 

20% best days, sulfate is significant in all of the Class I areas. The majority of this can be 

attributed to point sources. On the 20% worst days, organic carbon is the most significant 

species in all of the Class I areas, with natural fire having the largest contribution. 

The following sections provide an additional breakdown of the pollutant species that contribute 

to each Class I area. The first figure in each section shows a simple pie chart of the 20% best 

and 20% worst days, similar to the bar chart figures above. The second figure in each section

shows the pollutant species based on monthly averages for all days (including best or worst) 

during the baseline period, as an example of the seasonal variation in Class I areas. The third 

figure in each section presents a closer look at the daily variation during a given year--in this 

case 2004. The fourth figure in each section shows the improvement needed (shown in reduction 

in deciview) for each Class I area, from the baseline year to the 2018 milestone, and to 2064 

natural conditions. 

3.1 Yellowstone National Park, Grand Teton National Park and Teton Wilderness

As depicted in the following figures, on the best 20% days sulfate is the dominant species, but 

organic carbon is the largest contributor on the worst 20% days. Both sulfate and nitrate 
33

pollutant species fluctuate during the year. Significant spikes of organic carbon, however, are 

evident especially in the warmer months, most likely due to wildfire activity. Figure 3.1-4, 

indicates a 1.3 deciview reduction would be needed to meet a 2018 URP, and a 5.4 deciview 

reduction would be needed to meet a 2064 URP. While 51.308(d)(1)(i)(B) requires that the State 

disclose the incremental change required to meet a URP goal, there is no requirement to meet a 

URP goal. This is discussed in more detail in Chapter 7. 

Figure 3.1-1. Yellowstone IMPROVE Site - Average Pollutant Species Contribution to

 20% Best and 20% Worst Days Baseline (2000-2004) 

(http://vista.cira.colostate.edu/dev/web/AnnualSummaryDev/Composition.aspx) 

Figure 3.1-2. Yellowstone IMPROVE Site - Monthly Average Pollutant Species Variation 

 for All Days Sampled During the Baseline Period (2000-2004) 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
34

Figure 3.1-3. Yellowstone IMPROVE Site - Pollutant Species Variation for All Days

 Sampled in 2004 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Figure 3.1-4. Yellowstone IMPROVE Site - Baseline Worst Day Aerosol Composition 

 Compared to Visibility Improvement Needed by 2018 & 2064 
35

3.2 North Absaroka and Washakie Wilderness Areas

As depicted in the following figures, on the best 20% days sulfate is the dominant species, but 

organic carbon is the largest contributor on the worst 20% days. Both sulfate and nitrate 

pollutant species fluctuate during the year. Like the Yellowstone IMPROVE site, the North 

Absaroka IMPROVE site shows significant spikes of organic carbon, especially in the warmer 

months most likely due to wildfire activity. Figure 3.2-4, indicates a 1.1 deciview reduction 

would be needed to meet a 2018 URP, and a 4.7 deciview reduction would be needed to meet a 

2064 URP. While 51.308(d)(1)(i)(B) requires that the State disclose the incremental change 

required to meet a URP goal, there is no requirement to meet a URP goal. This is discussed in 

more detail in Chapter 7. 

Figure 3.2-1. North Absaroka IMPROVE Site - Average Pollutant Species Contribution to

 20% Best and 20% Worst Days Baseline (2000-2004) 

(http://vista.cira.colostate.edu/dev/web/AnnualSummaryDev/Composition.aspx) 
36

Figure 3.2-2. North Absaroka IMPROVE Site - Monthly Average Pollutant Species

 Variation for All Days Sampled During the Baseline Period (2000-2004) 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Figure 3.2-3. North Absaroka IMPROVE Site - Pollutant Species Variation for All Days 

 Sampled in 2004

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
37

Figure 3.2-4. North Absaroka IMPROVE Site - Baseline Worst Day Aerosol Composition 

 Compared to Visibility Improvement Needed by 2018 & 2064 

3.3 Bridger and Fitzpatrick Wilderness Areas

As with all other Wyoming Class I areas, on the best 20% days sulfate is the dominant species, 

but organic carbon is the largest contributor on the worst 20% days. Both sulfate and nitrate 

pollutant species fluctuate during the year. Like the other Class I sites, the Bridger IMPROVE 

site shows significant spikes of organic carbon, especially in the warmer months most likely due 

to wildfire activity. Figure 3.3-4, indicates a 1.1 deciview reduction would be needed to meet a

2018 URP, and a 4.6 deciview reduction would be needed to meet a 2064 URP. While 

51.308(d)(1)(i)(B) requires that the State disclose the incremental change required to meet a URP 

goal, there is no requirement to meet a URP goal. This is discussed in more detail in Chapter 7. 
38

Figure 3.3-1. Bridger IMPROVE Site - Average Pollutant Species Contribution to 20% 

 Best and 20% Worst Days Baseline (2000-2004) 

(http://vista.cira.colostate.edu/dev/web/AnnualSummaryDev/Composition.aspx) 

Figure 3.3-2. Bridger IMPROVE Site - Monthly Average Pollutant Species Variation for

 All Days Sampled During the Baseline Period (2000-2004) 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
39

Figure 3.3-3. Bridger IMPROVE Site - Pollutant Species Variation for All Days Sampled

 in 2004 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Figure 3.3-4. Bridger IMPROVE Site - Baseline Worst Day Aerosol Composition 

 Compared to Visibility Improvement Needed by 2018 & 2064 
40

CHAPTER 4

STATEWIDE EMISSION INVENTORY

4.1 Introduction

The process for inventorying sources is similar for all species of interest. The number and types 

of sources is identified by various methods. For example, major stationary sources report actual 

annual emission rates to the EPA national emissions database. Wyoming collects annual 

emission data from both major and minor sources and this information is used as input into the 

emissions inventory. In other cases, such as mobile sources, an EPA mobile source emissions 

model is used to develop emission projections. Population, employment and household data are 

used in other parts of the emissions modeling to characterize emissions from area sources such as 

home heating. Thus, for each source type, emissions are calculated based on an emission rate 

and the amount of time the source is operating. Emission rates can be based on actual 

measurements from the source, or EPA emission factors based on data from tests of similar types 

of emission sources. In essence all sources go through the same process. The number of sources 

is identified, emission rates are determined by measurements of those types of sources and the 

time of operation is determined. By multiplying the emission rate times the hours of operation in 

a day, a daily emission rate can be calculated. A second inventory is created to predict emissions 

in 2018 based on expected controls, growth, or other factors. Additional inventories are created 

for future years to simulate the impact of different control strategies. While the Division 

attempts to make sound estimates of all sources of emissions in the State, they are only estimates 

at one point in time. Oil and gas emission estimates are some of the more complicated emission 

inventories that the Division collects, and the Division is working hard to improve those 

estimates. 

The following presents the Wyoming emissions from the WRAP TSS.
41

4.2 SOx Emission Inventory 

Table 4.2-1. Wyoming SOx Emission Inventory - 2002 and 2018

Wyoming Planning and Preliminary Reasonable Progress 

Emission Inventories

Source Category

Statewide SOx

Plan 02d

(tpy)

PRP18b

(tpy)

Net Change

From Plan 02d

to PRP18b

(Percent)

Point 119,717 96,809 -19

Area 16,689 23,093 38

On-Road Mobile 959 81 -92

Off-Road Mobile 5,866 65 -99

Oil & Gas 150 3 -98

Road Dust 0 0 0

Fugitive Dust 0 0 0

Windblown Dust 0 0 0

Anthro Fire 173 109 -37

Natural Fire 2,286 2,286 0

Biogenic 0 0 0

Total 145,840 122,446 -16

 

Sulfur oxides (SOx) are compounds of sulfur and oxygen molecules. Sulfur dioxide (SO2) is the 

predominant form found in the lower atmosphere. Sulfur dioxide emissions produce sulfate 

particles in the atmosphere. Ammonium sulfate particles have a significantly greater impact on 

visibility than other pollutants like dust from unpaved roads due to the physical characteristics 

causing greater light scattering from the particles. Sulfur dioxide emissions come primarily from 

coal combustion at electrical generation facilities, but smaller amounts come from natural gas 

combustion, mobile sources and even wood combustion. There are natural sources of sulfur 

dioxide such as volcanoes. A 16% statewide reduction in SOx emissions is expected by 2018 

due to planned controls on existing sources, even with a growth consideration in generating 

capacity for the State. Similar reductions are expected from other states as BART or other 

planned controls take effect by 2018. 
42

4.3 NOx Emission Inventory 

Table 4.3-1. Wyoming NOx Emission Inventory - 2002 and 2018

Wyoming Planning and Preliminary Reasonable Progress

Emission Inventories

Source Category

Statewide NOx

Plan02d

(tpy)

PRP18b

(tpy)

Net Change 

From Plan02d 

to PRP18b

(Percent)

Point 117,806 110,109 -7

Area 15,192 19,663 29

On-Road Mobile 38,535 9,728 -75

Off-Road Mobile 76,637 49,677 -35

Oil & Gas 14,725 34,142 132

Road Dust 0 0 0

Fugitive Dust 0 0 0

Windblown Dust 0 0 0

Anthro Fire 782 484 -38

Natural Fire 8,372 8,372 0

Biogenic 15,925 15,925 0

Total 287,974 248,100 -14

Nitrogen oxides (NOx) are generated during any combustion process where nitrogen and oxygen 

from the atmosphere combine together under high temperature to form nitric oxide, and to a 

lesser degree nitrogen dioxide, and in much smaller amounts other odd oxides of nitrogen. 

Nitrogen oxides react in the atmosphere to form nitrate particles. Nitrogen oxide emissions in 

Wyoming are expected to decrease by 2018, primarily due to significant improvements in mobile 

sources. It is projected that off-road and on-road vehicles emissions will decline by more than 

55,760 tons per year from the Plan02d emissions total of 115,172 tons per year. Point sources 

are also projected to decrease statewide emissions by about 7,700 tons per year. A power plant 

would be a typical example of a point source. Oil and gas development is expected to increase 

statewide emissions from 2002 to 2018 by about 19,400 tons per year. With population 

increases and more construction, fugitive dust emissions will also increase. 
43

4.4 OC Emission Inventory

Table 4.4-1. Wyoming OC Emission Inventory - 2002 and 2018

Wyoming Planning and Preliminary Reasonable Progress

Emission Inventories

Source Category

Statewide OC

Plan02d

(tpy)

PRP18b

(tpy)

Net Change 

From Plan02d 

to PRP18b

(Percent)

Point 646 990 53

Area 2,000 1,975 -1

On-Road Mobile 304 249 -18

Off-Road Mobile 625 411 -34

Oil & Gas 0 0 0

Road Dust 20 26 30

Fugitive Dust 96 133 39

Windblown Dust 0 0 0

Anthro Fire 1,709 886 -48

Natural Fire 23,793 23,793 0

Biogenic 0 0 0

Total 29,193 28,463 -3

Organic carbon particles emitted directly from the combustion of organic materials are called 

primary organic aerosols. A wide variety of sources contribute to this classification including 

byproducts from wood and agricultural burning with emissions from natural fires as the largest 

contributor to organic carbon emissions. Since it is impossible to predict future emissions from 

natural fires, this category was held constant and organic carbon emissions from all sources are 

expected to show a 3% decline.
44

4.5 EC Emission Inventory 

Table 4.5-1. Wyoming EC Emission Inventory - 2002 and 2018

Wyoming Planning and Preliminary Reasonable Progress

Emission Inventories

Source Category

Statewide EC

Plan02d

(tpy)

PRP18b

(tpy)

Net Change 

From Plan02d 

to PRP18b

(Percent)

Point 104 180 73

Area 304 335 10

On-Road Mobile 443 86 -81

Off-Road Mobile 1,986 1,161 -42

Oil & Gas 0 0 0

Road Dust 2 2 0

Fugitive Dust 7 9 29

Windblown Dust 0 0 0

Anthro Fire 298 153 -49

Natural Fire 4,922 4,922 0

Biogenic 0 0 0

Total 8,066 6,848 -15

Elemental carbon is the carbon black, or soot, a byproduct of incomplete combustion. It is the 

partner to primary organic aerosols and represents the more complete combustion of fuel 

producing carbon particulate matter as the end product. A carbon particle has a sixteen times 

greater impact on visibility than that of a coarse particle of granite. Reductions in manmade 

emissions in elemental carbon are largely due to mobile sources and expected new Federal 

emission standards for mobile sources, especially for diesel engines. Fleet replacement will also 

play a part in the reduction. Elemental carbon emissions are predicted to decrease approximately 

15% by 2018. As with organic carbon, however, the overwhelming source for elemental carbon 

is from wildfires which the Division cannot control or predict future emissions. 
45

4.6 Fine PM Emission Inventory

Table 4.6-1. Wyoming Fine PM Emission Inventory - 2002 and

 2018

Wyoming Planning and Preliminary Reasonable Progress

Emission Inventories

Source Category

Statewide Fine PM

Plan02d

(tpy)

PRP18b

(tpy)

Net Change 

From 

Plan02d to 

PRP18b

(Percent)

Point 11,375 15,709 38

Area 1,601 1,756 10

On-Road Mobile 0 0 0

Off-Road Mobile 0 0 0

Oil & Gas 0 0 0

Road Dust 160 206 29

Fugitive Dust 2,082 2,882 38

Windblown Dust 5,838 5,838 0

Anthro Fire 242 129 -47

Natural Fire 1,535 1,535 0

Biogenic 0 0 0

Total 22,833 28,055 23

Fine soil emissions are largely related to agricultural and mining activities, windblown dust from 

construction areas and emissions from unpaved and paved roads. A particle of fine dust has a 

relative impact on visibility one tenth as great as a particle of elemental carbon. On any given 

visibility event where poor visual air quality is present in a scene, the impact of dust can vary 

widely. Agricultural activities, dust from unpaved roads and construction are prevalent in this 

source category and changes in emissions are tied to population and vehicle miles traveled. 

Since soil emissions are not directly from the tailpipe of the vehicle, the category of mobile 

sources does not show any emissions and all vehicle related emissions from paved and unpaved 

roads show up in the fugitive dust and road dust categories. 
46

4.7 Coarse PM Emission Inventory

Table 4.7-1. Wyoming Coarse PM Emission Inventory - 2002

 and 2018

Wyoming Planning and Preliminary Reasonable Progress

Emission Inventories

Source Category

Statewide Coarse PM

Plan02d

(tpy)

PRP18b

(tpy)

Net Change 

From Plan02d 

to PRP18b

(Percent)

Point 24,751 30,619 24

Area 409 653 60

On-Road Mobile 171 165 -4

Off-Road Mobile 0 0 0

Oil & Gas 0 0 0

Road Dust 1,125 1,449 29

Fugitive Dust 18,030 25,144 39

Windblown Dust 52,546 52,546 0

Anthro Fire 259 109 -58

Natural Fire 5,369 5,369 0

Biogenic 0 0 0

Total 102,660 116,054 13

Coarse mass particles emissions are closely related to the same sources as fine soil emissions but 

other activities like rock crushing and processing, material transfer, open pit mining and unpaved 

road emissions can be prominent sources. Coarse mass particles travel shorter distances in the 

atmosphere than some other smaller particles but can remain in the atmosphere sufficiently long 

enough to play a role in regional haze. Coarse mass particulate matter has the smallest direct 

impact on regional haze on a particle-by-particle basis where one particle of coarse mass has a 

relative visibility weight of 0.6 compared to a carbon particle having a weight of 10. Increases in 

coarse mass are seen in the fugitive and road dust categories, as well as point and area source 

categories. These increases are largely attributable to population growth, vehicle miles traveled 

and employment data.
47

4.8 Ammonia Emission Inventory 

Table 4.8-1. Wyoming Ammonia Emission Inventory - 2002

 and 2018

Wyoming Planning and Preliminary Reasonable Progress

Emission Inventories

Source Category

Statewide Ammonia

Plan02d

(tpy)

PRP18b

(tpy)

Net Change 

From 

Plan02d to 

PRP18b

(Percent)

Point 685 1,398 104

Area 29,776 29,901 0

On-Road Mobile 538 724 35

Off-Road Mobile 41 57 39

Oil & Gas 0 0 0

Road Dust 0 0 0

Fugitive Dust 0 0 0

Windblown Dust 0 0 0

Anthro Fire 218 119 -45

Natural Fire 1,775 1,775 0

Biogenic 0 0 0

Total 33,033 33,974 3

Ammonia emissions come from a variety of sources including wastewater treatment facilities, 

livestock operations, and fertilizer application and to a small extent, mobile and point sources. 

Increases in ammonia emissions are correlated to population statistics and increased vehicular 

traffic. Ammonia is directly linked to the production of ammonium nitrate and ammonium 

sulfate particles in the atmosphere when sulfur dioxide and nitrogen oxides eventually convert 

over to these forms of particles. Mobile source emissions are expected to rise due to increases in 

vehicle miles traveled. Future point source emissions are also expected to increase by 2018, 

however, little to no overall increases in ammonia are predicted for 2018. 

4.9 Inventories Utilized For Emissions Projections

The WRAP Regional Modeling Center (RMC) developed multiple annual emissions inventories 

for a 2002 actual emissions base case, a planning case to represent the 2000-04 regional haze 

baseline period using averages for key emissions categories, and a 2018 base case of projected 

emissions determined using factors known at the end of 2005. All emission inventories were 

developed using the Sparse Matrix Operator Kernel Emissions (SMOKE) modeling system. 

These inventories have undergone a number of revisions throughout the development process to 

arrive at the final versions used in CMAQ and CAMx air quality modeling.

 The 2002 base case emissions scenario, referred to as “2002 Base Case” or “Base02”, 

represents the actual conditions in calendar year 2002 with respect to ambient air quality 

and the associated sources of criteria and particulate matter air pollutants. The Base02 

emissions inventories are used to validate the air quality model and associated databases
48

and to demonstrate acceptable model performance with respect to replicating observed 

particulate matter air quality. 

 The 2000-04 baseline period planning case emissions scenario is referred to as “Plan02”, 

and represents baseline emission patterns based on average, or “typical”, conditions. 

This inventory provides a basis for comparison with the future year 2018 projected 

emissions, as well as to gauge reasonable progress with respect to future year visibility. 

Plan 02d, used by the State of Wyoming in these inventories, was last revised in October, 

2008. 

 The 2018 future-year base case emissions scenario, referred to as “2018 Base Case” or 

“Base18”, represents conditions in future year 2018 with respect to sources of criteria and 

particulate matter air pollutants, taking into consideration growth and controls. Modeling 

results based on this emission inventory are used to define the future year ambient air 

quality and visibility metrics.

 2018 Preliminary Reasonable Progress refers to a WRAP emissions or modeling scenario 

based on the preliminary reasonable progress emissions inventories, generated in early 

2007. This scenario includes corrections, refinements and additions to the 2018 Base 

Case, as well as estimates of controlling SO2 and some NOx from BART sources. The 

PRP18b analysis series, used by the State of Wyoming in these inventories, was last 

revised in August, 2009. 

The CMAQ and CAMx air quality models are explained in more detail in Chapter 5. 

4.10 PRP18b

A “base case” emissions projection inventory was compiled by the WRAP in January of 2006. 

In June 2007, a revision to this inventory named 2018 Preliminary Reasonable Progress version 

“a” (PRP18a) updated the first set (base case) of projections. The most recent projections, 2018 

Preliminary Reasonable Progress version “b” (PRP18b), provides a more current assessment of 

the reasonable progress toward visibility goals by the WRAP. Table 4.9-1 below depicts the net 

change from the PRP18a NOx emission inventories to the PRP18b emission inventories. 

Table 4.9-1. Net Change From PRP18a to PRP18b Emission Inventories 

Source 

Category 

PRP18a NOx

Emission 

Inventory

(tpy)

PRP18b NOx

Emission 

Inventory

(tpy)

Net Change 

From PRP18a 

to PRP18b 

(tpy)

Net Change 

From PRP18a 

to PRP18b 

(%)

Point 133,216 110,109 -23,107 -17%

Area (includes 

Oil & Gas) 53,806 53,805 No Change No Change 

On-Road Mobile 9,728 9,728 No Change No Change

Off-Road Mobile 59,378 49,676 -9,702 -16%

The off-road mobile category showed a 16% decrease in NOx emissions, 89% of which was 

attributable to locomotives. The remaining 11% was attributable to off-road equipment. A 
49

decrease of 17% in point source NOx emissions was achieved, with 89% of the decrease due to 

BART. Area and on-road source categories remained virtually unchanged. 

Three ERG Technical Memorandums, documenting PRP18a and PRP18b emission inventories, 

can be found in Chapter 4 of the Wyoming TSD. 
50

CHAPTER 5

SOURCE APPORTIONMENT AND REGIONAL HAZE MODELING

5.1 Overview

Visibility impairment occurs when pollutants emitted into the atmosphere scatter and absorb 

light, thereby creating haze. These pollutants can remain suspended in the atmosphere for long 

periods and be transported long distances, thereby contributing to regional-scale impacts on 

visibility in Class I areas. Air quality models offer the opportunity to better understand how 

these impacts occur, by identifying the sources that contribute to haze, and helping to select the 

most effective emissions reduction strategies to improve visibility.

Wyoming Class I area visibility is affected by a combination of local and regional transport of air 

pollutants. Chapter 4 provided information on emission inventories, as the first step in 

identifying significant source categories causing visibility impairment. This chapter describes 

the results of (1) source apportionment analysis showing the in-state and regional contribution of 

haze sources, for the 20% worst and best visibility days, and (2) regional modeling projections of 

visibility conditions by the 2018 benchmark or milestone, based on application of the regional 

haze strategies outlined in this Plan, including BART. The source apportionment information 

and regional modeling results are the basis for the demonstration of reasonable progress for the 

20% worst and best days, described in Chapter 7. 

Additional explanation of the source apportionment and modeling methodology can be found in 

the WRAP Air Quality Modeling methods document in Chapter 5 of the Wyoming TSD. 

5.1.1 Source Apportionment Analysis - PSAT and WEP

In order to determine the significant sources contributing to haze in Wyoming’s Class I areas, the 

Division has relied upon source apportionment analysis techniques provided by the WRAP for 

this Regional Haze Plan. This information can be found on the WRAP TSS website at 

http://vista.cira.colostate.edu/TSS/Results/HazePlanning.aspx. There were two techniques used 

for source apportionment of regional haze. One was the Particulate Matter Source 

Apportionment Technology (PSAT) tool, used for the attribution of sulfate and nitrate sources 

only. The second was the Weighted Emissions Potential (WEP) tool, used for attribution of 

sources of sulfate, nitrate, organic carbon, elemental carbon, fine PM, and coarse PM. 

PSAT uses the CAMx air quality model to show nitrate-sulfate-ammonia chemistry and applies

this chemistry to a system of tracers or “tags” to track the chemical transformations, transport 

and removal of NOx and SO2. Emission scenarios used for the PSAT analyses were the Plan02c 

and Base18b. PSAT results were not regenerated for use in this document using the more 

recently updated Plan02d and PRP18b emissions scenarios because of the time and resources 

that would have been required. No significant changes were anticipated with additional 

modeling runs. These two pollutants are important because they tend to originate from 

anthropogenic (human-caused) sources. Therefore, the results from this analysis can be useful in 

determining contributing sources that may be controllable, both in-state and in neighboring 

states.
51

WEP is a screening tool that helps to identify source regions that have the potential to contribute 

to haze formation at specific Class I areas. Unlike PSAT, this method does not account for 

chemistry or deposition. The WEP combines emissions inventories, wind patterns, and residence 

time of air mass over each area where emissions occur, to estimate the percent contribution of 

different pollutants. Like PSAT, the WEP tool compares baseline (2000-2004) to 2018, to show 

the improvement expected by the 2018 URP, for sulfate, nitrate, organic carbon, elemental 

carbon, fine PM, and coarse PM. 

As described in Section 5.2 below, the Division believes PSAT is a better tool than WEP for 

identifying the contribution of sulfates and nitrates to Wyoming Class I areas, because PSAT 

does account for chemistry and deposition, and is better at identifying regional contribution of 

sources from outside the WRAP region (see discussion in 5.2 below). For these reasons, the 

Division has relied upon the PSAT results as the primary source apportionment tool for sulfates 

and nitrates, and thus the better tool for identifying anthropogenic sources. The results from the 

WEP analysis were used by the Division primarily to identify the pollutants more commonly 

associated with non-anthropogenic (natural) sources. Even though these sources are mostly 

uncontrollable, it is still important to consider their relative contribution to haze. 

The review of PSAT results in this chapter (discussed in 5.2 below) focus on the contribution on 

sulfates and nitrates, while the WEP results focus on the contribution of organic carbon, 

elemental carbon, fine PM, and coarse PM.

5.1.2 Regional Haze Modeling - CMAQ

The primary tool utilized by the Division for modeling regional haze improvements by 2018, and 

for determining Wyoming’s Reasonable Progress Goals (see Chapter 7), was the Community 

Multi-Scale Air Quality (CMAQ) model. The CMAQ model was used to estimate 2018 

visibility conditions in Wyoming and all Western Class I areas, based on application of the 

regional haze strategies presented in this Plan, including assumed controls on BART sources. A 

more in depth description of the CMAQ model used to project 2018 visibility conditions can be 

found in the WRAP Air Quality Modeling document referenced in Chapter 5 of the Wyoming 

TSD.

The modeling was conducted by the Regional Modeling Center (RMC) at the University of 

California Riverside, under the oversight of the WRAP Modeling Forum. Results can be found 

on the WRAP TSS website at http://vista.cira.colostate.edu/tss/Results/HazePlanning.aspx. 

The CMAQ model was designed as a “one atmosphere” modeling system to encompass 

modeling of multiple pollutants and issues, including ozone, PM, visibility, and air toxics. This 

is in contrast to many earlier air quality models that focused on single pollutants. CMAQ takes 

into account emissions, advection and dispersion, photochemical transformation, aerosol 

thermodynamics and phase transfer, aqueous chemistry, and wet and dry deposition of trace 

species. The model requires inputs of three-dimensional gridded wind, temperature, humidity, 

cloud/precipitation, and boundary layer parameters. The current version of CMAQ can only 

utilize output fields from the MM5 meteorological model. MM5 is a state-of-the-science 
52

atmosphere model that has proven useful for air quality applications and has been used 

extensively in past local, state, regional, and national modeling efforts. MM5 has undergone 

extensive peer review, with all of its components continually undergoing development and 

scrutiny by the modeling community.

The RMC developed air quality modeling inputs including annual meteorology and emissions 

inventories for a 2002 actual emissions base case, a planning case to represent the 2000-2004 

regional haze baseline period using averages for key emissions categories, and a 2018 base case 

of projected emissions determined using factors known at the end of 2005. All emission 

inventories were prepared for CMAQ using the Sparse Matrix Operator Kernel Emissions 

(SMOKE) modeling system. Each of these inventories underwent a number of revisions 

throughout the development process to arrive at the final versions used in CMAQ modeling. The 

development of each of these emission scenarios is documented under the emissions inventory 

sections of the TSS. 

The 2018 visibility projections were made using the Plan02d and PRP18b CMAQ 36-km 

modeling results. Projections were made using relative response factors (RRFs) for each species: 

1) RRF = [2018 Modeled Species/Baseline Modeled Species]

2) Projected Species Mass = Baseline IMPROVE Species x RRF

3) Projected Species Extinction = Conversion via IMPROVE Algorithm of Projected 

Species Mass

There are three RRF calculation methods. These methods differ in how the days for the 

calculation are selected. The Specific Days (EPA) method is the EPA default method, and single 

species’ RRFs are calculated across observed (IMPROVE) worst or best days in the base model 

year. The Specific Days (EPA) method was the method utilized by the State of Wyoming. The 

second method is the Quarterly Weighted method, whereby four quarterly species’ RRFs are 

calculated from the 20% worst or best days in each quarter, in spite of how those days compare 

to the overall annual worst and best days. The third method is the Monthly Weighted method, 

whereby twelve monthly species’ RRF are calculated from the 20% best or worst days in each 

month, regardless of how those days compare to the overall annual worst and best days. 

More information on how to use the visibility tool in connection with RRF factors can be found 

at http://vista.cira.colostate.edu/tss/help/GettingStarted.aspx#MP, and specific information regarding how 

RRF factors are calculated can be found in Section 6.4 of the 2007 EPA document “Guidance on the Use 

of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and 

Regional Haze” at http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf. 

This EPA guidance was followed for setting up the “EPA Specific Days” option and other inputs 

on the WRAP TSS Visibility Projections Tool, so all Class I areas in the WRAP region used 

their IMPROVE site-specific monitoring and modeling data to derive the RRFs.

Generally, emissions inputs were prepared by individual states and tribes for point, area, and 

most dust emissions categories. The following WRAP Forums were relied upon to summarize 

this data and provide it to the RMC: 
53

 Point Source emissions were obtained from projects commissioned by the Stationary 

Sources Joint Forum and the Emissions Forum. 

 Area Source emissions were obtained from projects commissioned by the Stationary 

Sources Joint Forum and the Emissions Forum. 

 Mobile Source emissions were from projects commissioned by the Emissions Forum.

 Fire (natural and anthropogenic) emissions were from projects commissioned by the Fire 

Emissions Joint Forum.

 Ammonia, Dust, and Biogenic emissions were from projects commissioned by the Dust 

Emissions Joint Forum and the Modeling Forum. 

 Emissions from Pacific offshore shipping were from a project conducted by the RMC.

1

 Other emissions from North America were from projects commissioned by the Emissions 

Forum and the Modeling Forum. The Mexico emissions are from 1999, and were held 

constant for 2018. Canada emissions are from 2000 and were held constant for 2018. 

 Boundary conditions reaching North America from the rest of the world were from a 

project commissioned by the VISTAS Regional Planning Organization, on behalf of the 

five regional planning organizations working on regional haze. 

The results from the CMAQ regional modeling analysis are discussed later in this section.

Because some WRAP states are still going through the difficult case-by-case BART 

determinations for each EGU, the WRAP was not able to model all of the emission reductions 

from BART and State long-term strategies in the most recent modeling effort. Therefore, the 

modeling results and all graphics associated with the modeling results do not include BART and 

long-term strategy reductions proposed in this SIP or any other WRAP SIPs that were not 

available at the time WRAP modeled. The WRAP was only able to include enforceable 

reductions that were on the books at the time of the last model run. 

5.2 Major Source Categories Contributing to Haze in Wyoming

Figures in this section show profiles of the relative contribution of in-state vs. out-of-state 

sources contributing to emissions in Wyoming’s Class I areas, for the 20% worst and best days, 

for the baseline (2000-2004) and future year (2018) scenarios, using the PSAT and WEP 

techniques. The Wyoming Class I areas are grouped by general location (based on 

representative IMPROVE monitoring sites).

As previously described, there are several differences between the PSAT and WEP techniques. 

PSAT focuses on sulfate and nitrate contribution only, taking into account chemistry and 

deposition. PSAT also estimates the contribution from all regions--the WRAP states, CENRAP 

states2

, Canada, Mexico, Pacific offshore (shipping), and “outside the domain” (global 

transport). The WEP does not address sulfate and nitrate chemistry and deposition, and while it 

 

1 See WRAP TSS website under “Resources”, “Emissions”, and “Offshore Emissions” for summary, or go to 

http://vista.cira.colostate.edu/docs/wrap/emissions/OffshoreEmissions.doc. 

2 CENRAP is a regional planning organization similar to the WRAP that is comprised of Nebraska, Kansas, 

Oklahoma, Texas, Minnesota, Iowa, Missouri, Arkansas, and Louisiana.
54

does estimate the contribution from Canada and Pacific offshore regions, it does not include 

other regional contributions. 

Based on these differences, the figures provided below focus on PSAT results for identifying the 

contribution of sulfates and nitrates (the primary anthropogenic source pollutants) and WEP 

results for identifying the contribution of organic carbon, elemental carbon, fine PM, and coarse 

PM (commonly associated with non-anthropogenic sources). 

Sections 5.2.1 through 5.2.4 below show 20% worst- and best-day PSAT profiles on the 

contribution of sulfate and nitrate at each IMPROVE monitoring site representing the Class I 

areas in Wyoming. The pie charts display relative regional contributions to total annual modeled 

sulfate and nitrate mass at the respective sites. The WRAP contribution is separated from the 

rest of the pie for easy identification. The remaining pie slices are outside the Western United 

States, for the regions described above. 

The PSAT bar charts below the pie charts display source region and source category 

contributions of sulfate and nitrate mass. There are five source categories listed--point, area, 

mobile, anthropogenic fires (controlled burning), and natural and biogenic sources (mostly 

wildfire and windblown dust). Estimated contributions outside the modeling domain (Outside 

Domain) are also shown, and include Mexico, Canada, and Pacific offshore emissions. 

Sections 5.2.5 through 5.2.12 present WEP profiles for organic carbon, elemental carbon, fine 

PM, and coarse PM, at Class I areas in Wyoming.

Unlike the PSAT figures, the WEP figures are bar charts only and summarize weighted 

emissions by state and region for 12 source categories. These categories are windblown dust, 

fugitive dust, road dust, off-road mobile, on-road mobile, off-shore, WRAP area oil and gas, 

area, biogenic, natural fire, anthropogenic fire, and point. This analysis used more source 

categories than the PSAT analysis to account for the additional pollutant types, and the more 

natural origins contributing to these pollutants, including dust and fire sources. 

5.2.1 PSAT Regional Contribution to Sulfate on 20% Worst Days

Figures 5.2.1-1 through 5.2.1-3 in this section illustrate the state and regional contribution of 

sulfate to the 20% worst days in Wyoming Class I areas for 2002 and 2018, based on PSAT 

profiles for each IMPROVE monitoring site representing the nearest Class I areas. The figures 

below consist of a pie chart that shows the estimated contribution of the major regions (WRAP 

states, Pacific Offshore, CENRAP, Eastern U.S., Canada, Mexico, and Outside Domain 

(global)). The bar chart is the WRAP source region portion, depicting Wyoming and other 

western states.

Note that in all the figures in this section, the majority of sulfate emissions originate outside the 

WRAP region. However, the nitrate contribution, discussed in Sections 5.2.3 and 5.2.4, is much 

higher within the WRAP region. The WRAP contribution is about one-third of the total, with the 

exception of the Bridger site, where the contribution is more than one-half. The largest 

contributor is outside the domain, or “global”. Among the other regions (not including the 
55

WRAP region), Canada, followed by Pacific Offshore and Mexico are the next sizable 

contributors. 

Also indicated in these figures, the largest contributor of sulfate is generally from point sources. 

The variation in sulfate contribution is based on the location of the Class I area monitoring site in 

the State. For example, the contribution of sulfate from Canada and Montana are the highest in 

the northernmost Class I area monitoring site, the North Absaroka Wilderness area. Similarly, 

the sulfate contribution from Mexico is highest in the southernmost Class I area monitoring site, 

the Bridger Wilderness area.

In terms of comparison of 2002 and 2018, it can be seen that the WRAP portion of the pie chart 

remains nearly unchanged, with only slight increases in 2018. The source category that accounts 

for this slight increase is primarily point.

Figure 5.2.1-1. PSAT Sulfate Contribution at Yellowstone NP, Grand Teton NP, and Teton 

 Wilderness on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
56

It is interesting to note that for the 20% worst days at Yellowstone, the point source sulfate 

contribution is approximately the same from Idaho as from Wyoming, most likely due to the 

proximity of industrial sources and wind direction. There is also a noticeable contribution from 

point sources in Canada, and a sizeable contribution from Mexico. Area and mobile sources 

from Wyoming and Idaho are much less. Close to half of the sulfate comes from the area outside 

the domain. 

Figure 5.2.1-2. PSAT Sulfate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

It should be noted that for the 20% worst days at North Absaroka, point source sulfate 

contribution is higher from Canada and Montana than from Wyoming, most likely due to the 

proximity of industrial sources and wind direction. There is a much larger sulfate contribution 

from Canada at the North Absaroka monitoring site than the other two monitoring sites 

(Yellowstone and Bridger). Area and mobile sources are very minimal contributors to sulfate in 

Wyoming. Approximately one half of the sulfate source is generated from the area outside the 

domain.
57

Figure 5.2.1-3. PSAT Sulfate Contribution at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

For the 20% worst days at the Bridger monitoring site, overall sulfate levels are slightly higher 

compared to the Yellowstone and North Absaroka monitoring sites. The majority of the sulfate 

originates from point sources in Wyoming, Idaho, and Utah. There are also considerable 

contributions from Canada and Mexico. Area and mobile sources, again, contribute a small 

amount of sulfate in Wyoming. Approximately one-third of the sulfate is generated from the 

area outside the domain.

5.2.2 PSAT Regional Contribution to Sulfate on 20% Best Days

Figures 5.2.2-1 through 5.2.2-3 in this section illustrate the state and regional contribution of 

sulfate to the 20% best days in Wyoming Class I areas for 2002 and 2018, based on PSAT 

profiles for each IMPROVE monitoring site representing the nearest Class I areas. The figures 

below consist of a pie chart that shows the estimated contribution of the major regions (WRAP 

states, Pacific Offshore, CENRAP, Eastern U.S., Canada, Mexico, and Outside Domain 
58

(global)). The bar chart is the WRAP source region portion, depicting Wyoming and other 

western states.

Note that in all the figures in this section, the majority of sulfate emissions originate outside the 

WRAP region. However, the nitrate contribution, discussed in Sections 5.2.3 and 5.2.4, is much 

higher within the WRAP region. The WRAP contribution is about one-third to just less than 

one-half of the total. The largest contributor is outside the domain, or “global”. Among the 

other regions (not including the WRAP region), Canada, followed by Pacific Offshore are the 

next sizable contributors. 

Also indicated in these figures, the largest contributor of sulfate is generally from point sources. 

The variation in sulfate contribution is based on the location of the Class I area monitoring site in 

the State. For example, the contribution of sulfate from Canada is the highest in the 

northernmost Class I area monitoring site, the North Absaroka Wilderness area. Similarly, the 

sulfate contribution from Idaho is highest in the southernmost Class I area monitoring site, the 

Bridger Wilderness area.

In terms of comparison of 2002 and 2018, it can be seen that the WRAP portion of the pie chart 

increases only slightly in 2018. The source category that accounts for this slight increase is 

primarily point.
59

Figure 5.2.2-1. PSAT Sulfate Contribution at Yellowstone NP, Grand Teton NP, and Teton 

 Wilderness Area on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

It is interesting to note that for the 20% best days at Yellowstone, the point source sulfate 

contribution is approximately four times greater from Idaho and more than twice as much from 

Canada as from Wyoming, most likely due to the proximity of industrial sources and wind 

direction. There are also noticeable contributions from point sources in Utah, Montana, Nevada, 

Washington and Oregon. The largest area and mobile source contribution comes from Idaho, 

followed by Pacific Offshore and Canada. About half of the sulfate comes from the area outside 

the domain. 
60

Figure 5.2.2-2. PSAT Sulfate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

It should be noted that for the 20% best days at North Absaroka, point source sulfate contribution 

is several times higher from Canada and Idaho than from Wyoming, most likely due to the 

proximity of industrial sources and wind direction. There is a much larger sulfate contribution 

from Canada at the North Absaroka monitoring site than the other two monitoring sites 

(Yellowstone and Bridger). Area and mobile sources are very minimal contributors to sulfate in 

Wyoming. Approximately one half of the sulfate source is generated from the area outside the 

domain. 
61

Figure 5.2.2-3. PSAT Sulfate Contribution at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best days at the Bridger monitoring site, overall sulfate levels are approximately the 

same as Yellowstone and slightly lower than the North Absaroka monitoring site. The majority 

of the sulfate originates from point sources in Idaho, with much smaller amounts from Wyoming, 

Utah, and Nevada, respectively. Area and mobile sources, again, contribute a small amount of 

sulfate in Wyoming. Well over one-half of the sulfate is generated from the area outside the 

domain. 

5.2.3 PSAT Regional Contribution to Nitrate on 20% Worst Days 

Figures 5.2.3-1 through 5.2.3-3 in this section illustrate the state and regional contribution of 

nitrate to the 20% worst days in Wyoming Class I areas for 2002 and 2018, based on PSAT 

profiles for each IMPROVE monitoring site representing the nearest Class I areas.

In all the figures in this section, most of the nitrate originates from within the WRAP region, as 

opposed to the sulfate contribution, which is mostly derived from outside the WRAP. The 

WRAP contribution ranges from approximately one-half to nearly three-quarters of the total. 
62

Other sizeable contributions of nitrate are generated from outside the domain, and to a much 

lesser extent, Canada and Pacific offshore. Contributions from other regions are negligible. 

These figures indicate that overall, the majority of nitrate stems from mobile sources. In all but 

one of the Class I area monitors (Bridger), contributions from other states and Canada are much 

larger than contributions from inside Wyoming. 

In terms of comparison of 2002 and 2018, these figures indicate that the WRAP portion of the 

pie chart has a significant decrease in nitrate by 2018. Most of this decrease can be attributed to 

the numerous Federal and state “on-the-books” requirements for mobile sources (see Chapter 8, 

Long-Term Strategy).

Figure 5.2.3-1. PSAT Nitrate Contribution at Yellowstone NP, Grand Teton NP, and Teton 

 Wilderness Area on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

For the 20% worst days at Yellowstone, significant nitrate contributions can be seen from Idaho, 

Washington, and to a lesser extent, Oregon, Utah and Wyoming. Mobile sources make up the 

majority of the overall contributions. However, the projected 2018 area source contributions for 
63

Idaho and Wyoming exceed the mobile source contribution. In most cases, nitrate contributions 

are projected to decline significantly by 2018, with the exception of a small increase within 

Wyoming.

Figure 5.2.3-2. PSAT Nitrate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

For the 20% worst days, significant nitrate contributions for North Absaroka can be seen from 

Idaho, Montana, and Canada. The extent of contribution from Montana and Canada is greater at 

this monitoring site due to their close proximity. The extent of Idaho’s contribution is less at this 

site compared to the Yellowstone site, also due to proximity. Smaller contributions of nitrate 

originate from Wyoming, Washington, Utah, and Oregon. Mobile sources appear to be the 

dominant contributor overall; however, point sources in Montana are a large factor.
64

Figure 5.2.3-3. PSAT Nitrate Contribution at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

Unlike Yellowstone and North Absaroka, for the 20% worst days the largest nitrate contribution 

for Bridger originates within Wyoming. Point sources in 2002 and projected area and point 

sources in 2018 appear to be the largest contributors within Wyoming. The next highest 

contribution comes from Utah, followed by Idaho. It is interesting to note that contributions 

from California (mostly mobile source) in 2002 were greater than contributions from Canada or 

Montana. 

5.2.4 PSAT Regional Contribution to Nitrate on 20% Best Days

Figures 5.2.4-1 through 5.2.4-3 in this section illustrate the state and regional contribution of 

nitrate to the 20% best days in Wyoming Class I areas for 2002 and 2018, based on PSAT 

profiles for each IMPROVE monitoring site representing the nearest Class I areas.

In all the figures in this section, most of the nitrate originates from within the WRAP region, as 

opposed to the sulfate contribution, which is mostly derived from outside the WRAP. The 
65

WRAP contribution ranges from approximately one-half to nearly three-quarters of the total. 

Other sizeable contributions of nitrate are generated from outside the domain, and to a much 

lesser extent, Canada and Pacific offshore. Contributions from other regions are negligible. 

These figures indicate that overall, the majority of nitrate stems from mobile sources. Point and 

area sources are the next largest categories of nitrate contribution, especially at the Bridger 

monitoring site, where Wyoming’s area and point source contribution is the most sizeable. In all 

but one of the Class I area monitors (Bridger), contributions from other states and Canada are 

much larger than contributions from inside Wyoming. 

In terms of comparison of 2002 and 2018, these figures indicate that the WRAP portion of the 

pie chart has a significant decrease in nitrate by 2018. Most of this decrease can be attributed to 

the numerous Federal and state “on-the-books” requirements for mobile sources (see Chapter 8, 

Long-Term Strategy).

Figure 5.2.4-1. PSAT Nitrate Contribution at Yellowstone NP, Grand Teton NP, and Teton 

 Wilderness Area on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
66

For the 20% best days at Yellowstone, significant nitrate contributions can be seen from Idaho, 

Utah, California and Washington, and to a lesser extent, Canada, Montana, Oregon and 

Wyoming. Mobile sources make up the majority of the overall contributions. Nitrate 

contributions are projected to decline significantly by 2018. 

Figure 5.2.4-2. PSAT Nitrate Contribution at North Absaroka Wilderness and Washakie

 Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best days, significant nitrate contributions for North Absaroka can be seen from 

Idaho, Canada, Utah, California and Montana. The extent of contribution from these states and 

Canada is due in part to wind direction and proximity. The extent of Idaho’s contribution is less 

at this site compared to the Yellowstone site, due mostly to proximity. Smaller contributions of 

nitrate originate from Washington, Nevada, Oregon, Wyoming and North Dakota. Mobile 

sources appear to be the dominant contributor overall; however, point sources in Utah and 

California and area sources in Idaho and Canada are a large factor.
67

Figure 5.2.4-3. PSAT Nitrate Contribution at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best days the largest nitrate contribution for Bridger originates within Utah. Mobile 

and point sources appear to be the largest contributors within Utah. The next highest 

contribution comes from Idaho, followed by Wyoming and California. It is interesting to note 

that contributions from California (mostly mobile source) were greater than contributions from 

Canada or Montana.

5.2.5 WEP Potential Contribution to OC on 20% Worst Days

Figures 5.2.5-1 through 5.2.5-3 in this section represent the contribution of organic carbon to the 

20% worst days in Wyoming Class I areas for 2002 and 2018, based on the WEP profile for each 

IMPROVE monitoring site representing the nearest Class I areas.

In general, the figures below primarily reflect the contribution of fire sources - mostly natural 

fire (wildfire) and to a lesser degree, anthropogenic or controlled burning (forestry, agricultural, 

and residential burning). Area source organic carbon is from woodstoves and other urban related 
68

sources. Area source contributions of organic carbon are the lowest at the Yellowstone Class I 

area monitoring site due to its location, which is not near any urban areas. 

When comparing 2002 and 2018, the figures show a slight reduction in future years, mainly due 

to a projected drop in anthropogenic fires. Most other sources remain fairly constant. 

The WRAP TSS website states that the Primary Organic Aerosol parameter represents organic 

carbon compounds emitted directly as particulates, but not secondary organics which condense 

from a gaseous state after being emitted.

Figure 5.2.5-1. WEP Potential Contribution to OC at Yellowstone NP, Grand Teton NP,

 and Teton Wilderness Area on 20% Worst Visibility Days

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

For the 20% worst visibility days at Yellowstone, the most sizeable organic carbon contribution 

is from Wyoming natural fire sources, and to a minimal extent, anthropogenic fire followed by 

area sources. A much smaller contribution from these sources in Idaho can be seen. 
69

Figure 5.2.5-2. WEP Potential Contribution to OC at North Absaroka Wilderness and

 Washakie Wilderness Areas on 20% Worst Visibility Days

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

For the 20% worst visibility days at North Absaroka, the most sizeable organic carbon 

contribution is from Wyoming natural fire sources, and to a minimal extent, anthropogenic fire 

followed by area sources. However, a large contribution from these sources also comes from 

Idaho, followed by Montana, and to a lesser extent, Oregon.

Figure 5.2.5-3. WEP Potential Contribution to OC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Worst Visibility Days

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

For the 20% worst visibility days at Bridger, the most sizeable organic carbon contribution is 

from Wyoming natural fire sources, and to a minimal extent, area sources, followed by 
70

anthropogenic fire. Idaho, Oregon, Utah and California are the next largest contributors, 

respectively.

5.2.6 WEP Potential Contribution to OC on 20% Best Days

Figures 5.2.6-1 through 5.2.6-3 in this section represent the contribution of organic carbon to the 

20% best days in Wyoming Class I areas for 2002 and 2018, based on the WEP profile for each 

IMPROVE monitoring site representing the nearest Class I areas.

In general, the figures below primarily reflect the contribution of fire sources - mostly natural 

fire (wildfire) and to a lesser degree, anthropogenic or controlled burning (forestry, agricultural, 

and residential burning). Area source organic carbon is from woodstoves and other urban related 

sources. Area source contributions of organic carbon are the lowest at the Yellowstone Class I 

area monitoring site due to its location, which is not near any urban areas. 

When comparing 2002 and 2018, the figures show a slight reduction in future years, mainly due 

to a projected drop in anthropogenic fires. Most other sources remain fairly constant. 

The WRAP TSS website states that the Primary Organic Aerosol parameter represents organic 

carbon compounds emitted directly as particulates, but not secondary organics which condense 

from a gaseous state after being emitted.

Figure 5.2.6-1. WEP Potential Contribution to OC at Yellowstone NP, Grand Teton NP, 

 and Teton Wilderness Area on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best visibility days at Yellowstone, the most sizeable organic carbon contribution is 

from Wyoming natural fire sources, and to a minimal extent, anthropogenic fire followed by area 

sources. A much smaller contribution from these sources in Idaho can be seen.
71

Figure 5.2.6-2. WEP Potential Contribution to OC at North Absaroka Wilderness and

 Washakie Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best visibility days at North Absaroka, the most sizeable organic carbon 

contribution is from Wyoming natural fire sources, and to a minimal extent, anthropogenic fire 

followed by area sources. However, a contribution from these sources nearly equal in size 

comes from Idaho. Oregon, Montana and California, respectively, are the next largest 

contributors. 

Figure 5.2.6-3. WEP Potential Contribution to OC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
72

For the 20% best visibility days at Bridger, the most sizeable organic carbon contribution is from 

Wyoming natural fire sources, and to a minimal extent, area and anthropogenic fire sources. 

Idaho, Oregon, California and Utah are the next largest contributors, respectively.

5.2.7 WEP Potential Contribution to EC on 20% Worst Days 

Figures 5.2.7-1 through 5.2.7-3 in this section represent the contribution of elemental carbon to 

the 20% worst days in Wyoming Class I areas for 2002 and 2018, based on the WEP profile for 

each IMPROVE monitoring site representing the nearest Class I areas.

In general, the figures below primarily reflect the contribution of fire sources - mostly natural 

fire (wildfire) and to a much lesser degree, off-road mobile and anthropogenic or controlled 

burning (forestry, agricultural, and residential burning). Off-road mobile elemental carbon 

contributions are minimal to none at Yellowstone compared to North Absaroka and Bridger. 

When comparing 2002 and 2018, the figures show a reduction in future years, mainly due to a 

projected drop in off-road mobile and anthropogenic fire emissions. Most other sources remain 

fairly constant. 

Figure 5.2.7-1. WEP Potential Contribution to EC at Yellowstone NP, Grand Teton NP, 

 and Teton Wilderness Area on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

For the 20% worst visibility days at Yellowstone, the most sizeable elemental carbon 

contribution is from Wyoming natural fire sources, and to a minimal extent, anthropogenic fire. 

A much smaller contribution from these sources, except for off-road mobile, can be seen in 

Idaho. 
73

Figure 5.2.7-2. WEP Potential Contribution to EC at North Absaroka Wilderness and 

 Washakie Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

At North Absaroka for the 20% worst visibility days, natural fire sources from Wyoming is the 

largest contributor to elemental carbon, followed by anthropogenic fire and off-road mobile, and 

to a much lesser extent, area sources and on-road mobile. Idaho contributes a significant amount 

of these sources, followed by Montana and to a lesser extent, Oregon. California, Washington 

and Utah, respectively, also show some measurable contributions from these sources. 

Figure 5.2.7-3. WEP Potential Contribution to EC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)
74

For the 20% worst visibility days at Bridger, Wyoming is the largest contributor. Natural fire is 

the largest component of contribution followed by off-road mobile, anthropogenic fire, area and 

on-road mobile, respectively. Idaho, Utah, Oregon and California, respectively, have the next 

sizeable contributions from these sources at this site. 

5.2.8 WEP Potential Contribution to EC on 20% Best Days

Figures 5.2.8-1 through 5.2.8-3 in this section represent the contribution of elemental carbon to 

the 20% best days in Wyoming Class I areas for 2002 and 2018, based on the WEP profile for 

each IMPROVE monitoring site representing the nearest Class I areas.

In general, the figures below primarily reflect the contribution of fire sources - mostly natural 

fire (wildfire) and to a much lesser degree, off-road mobile and anthropogenic or controlled 

burning (forestry, agricultural, and residential burning). Off-road mobile elemental carbon 

contributions are smaller at Yellowstone compared to North Absaroka and Bridger. 

When comparing 2002 and 2018, the figures show a reduction in future years, mainly due to a 

projected drop in off-road mobile and anthropogenic fire emissions. Most other sources remain 

fairly constant. 

Figure 5.2.8-1. WEP Potential Contribution to EC at Yellowstone NP, Grand Teton NP,

 and Teton Wilderness Area on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best visibility days at Yellowstone, the most sizeable elemental carbon contribution 

is from Wyoming natural fire sources, and to a minimal extent, anthropogenic fire followed by 

off-road mobile. A smaller contribution from these sources, except for off-road mobile, can be 

seen in Idaho. 
75

Figure 5.2.8-2. WEP Potential Contribution to EC at North Absaroka Wilderness and 

 Washakie Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

At North Absaroka for the 20% best visibility days, natural fire sources from Wyoming, Idaho, 

Oregon and Montana are the largest contributors to elemental carbon. The next largest source is 

off-road mobile, mainly originating in Idaho and Utah. Anthropogenic fire, area sources and onroad mobile contribute to a much smaller degree in comparison to natural fire and off-road 

mobile. Idaho contributes the most significant amount of elemental carbon overall, followed by 

Wyoming, Oregon, Montana, Utah and California, respectively. 

Figure 5.2.8-3. WEP Potential Contribution to EC at Bridger Wilderness and Fitzpatrick

 Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
76

For the 20% best visibility days at Bridger, Wyoming is the largest contributor. Natural fire is 

the largest component of contribution followed by off-road mobile, anthropogenic fire, area and 

on-road mobile, respectively. Idaho, Utah, Oregon and California, respectively, have the next 

sizeable contributions from these sources at this site. 

5.2.9 WEP Potential Contribution to Fine PM on 20% Worst Days

Figures 5.2.9-1 through 5.2.9-3 in this section illustrate the contribution of fine PM to the 20% 

worst days in Wyoming Class I areas for 2002 and 2018, based on the WEP profile for each 

IMPROVE monitoring site representing the nearest Class I areas.

In general, the figures below represent contributions which consist predominantly of dust sources 

(mining, construction, unpaved roads and agriculture), with smaller contributions from area 

sources (woodstoves, etc.) and point sources, followed by natural fire and anthropogenic fire. 

Note that the largest contribution from natural fire in all three figures originates in Wyoming, 

with the most sizeable contribution affecting the Yellowstone monitoring site. 

When comparing 2002 and 2018, these figures indicate a consistent increase in most cases in fine 

PM emissions, primarily from dust sources. However, at the Bridger site, a small increase in 

point source contribution is noted. 

Figure 5.2.9-1. WEP Potential Contribution to Fine PM at Yellowstone NP, Grand Teton

 NP, and Teton Wilderness Area on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

The 20% worst visibility days at Yellowstone are dominated by fine PM contributions from dust 

sources in Idaho and Montana. Idaho also contributes a sizeable amount of fine PM area source 

emissions. Wyoming’s fine PM contributions are slightly higher than Montana’s, but originate 

mainly from natural fire sources, followed by dust sources. Less significant PM contributions 

from dust sources are noted in Washington, Oregon, Canada, and Utah, respectively. 
77

Figure 5.2.9-2. WEP Potential Contributions to Fine PM at North Absaroka Wilderness

 and Washakie Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

Dust sources in Montana are the overwhelming fine PM contributor for the 20% worst visibility 

days at North Absaroka, mainly due to the proximity of the monitoring site. The next largest 

contributor is Idaho, followed closely by Wyoming and Canada. The second largest source in 

Wyoming is natural fire, and in Idaho and Montana it is area sources. Dust sources in 

Washington and Oregon contribute to fine PM at North Absaroka, but to a much lesser degree. 

Figure 5.2.9-3. WEP Potential Contribution to Fine PM at Bridger Wilderness and

 Fitzpatrick Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)
78

For the 20% worst visibility days at Bridger, Wyoming is the dominant contributor to fine PM. 

Contributions are split fairly evenly between dust sources, point sources and natural fire, with 

dust sources being slightly more predominant. Idaho has quite sizeable contributions consisting 

of dust sources, followed by area sources. Utah is the next largest contributor with dust sources 

followed by point sources making up the majority of the components. Montana, Oregon, 

Washington, California and Canada, respectively, all have sizeable contributions of fine PM as 

well.

5.2.10 WEP Potential Contribution to Fine PM on 20% Best Days

Figures 5.2.10-1 through 5.2.10-3 in this section illustrate the contribution of fine PM to the 20% 

best days in Wyoming Class I areas for 2002 and 2018, based on the WEP profile for each 

IMPROVE monitoring site representing the nearest Class I areas.

In general, the figures below represent contributions which consist predominantly of dust sources 

(mining, construction, unpaved roads and agriculture), with smaller contributions from area 

sources (woodstoves, etc.) and point sources, followed by natural fire and anthropogenic fire. 

Note that the largest contribution from natural fire in all three figures originates in Wyoming, 

with the most sizeable contribution affecting the Yellowstone monitoring site.

When comparing 2002 and 2018, these figures indicate a consistent increase in most cases in fine 

PM emissions, primarily from dust sources. However, in all three figures, a small increase in 

point source contribution is noted. 

Figure 5.2.10-1. WEP Potential Contribution to Fine PM at Yellowstone NP, Grand Teton 

 NP, and Teton Wilderness Area on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

The 20% best visibility days at Yellowstone are dominated by fine PM contributions from dust 

sources in Idaho, Wyoming and Montana. Idaho also contributes a sizeable amount of fine PM 

area source emissions. Wyoming’s fine PM contributions originate mainly from natural fire 
79

sources, followed by dust sources. Significant PM contributions from dust sources are also noted 

in Utah and Oregon, and to a lesser degree in California, Canada, Washington and Nevada. 

Figure 5.2.10-2. WEP Potential Contribution to Fine PM at North Absaroka Wilderness

 and Washakie Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Dust sources in Montana and Idaho are the overwhelming fine PM contributors for the 20% best 

visibility days at North Absaroka. The next largest contributor is Wyoming, followed closely by 

Utah, Oregon, Canada, Washington and California, respectively. The second largest source in 

Wyoming is natural fire, and in Montana and Idaho it is area sources. 

Figure 5.2.10-3. WEP Potential Contribution to Fine PM at Bridger Wilderness and

 Fitzpatrick Wilderness Areas on 20% Best Visibility Days

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
80

For the 20% best visibility days at Bridger, Idaho is the dominant contributor to fine PM, 

followed by Wyoming and Utah. Dust sources are predominant, followed by natural fire, point, 

and area sources. Montana, Oregon, California, Nevada and Washington, respectively, are the 

next largest contributors. Dust sources, followed by area and point sources, make up the 

majority of the contribution components from these states.

5.2.11 WEP Potential Contribution to Coarse PM on 20% Worst Days 

Figures 5.2.11-1 through 5.2.11-3 in this section illustrate the contribution of coarse PM to the 

20% worst days in Wyoming Class I areas for 2002 and 2018, based on WEP profiles for each 

IMPROVE monitoring site representing the nearest Class I areas.

The figures below show that the profile for coarse PM is dominated by road dust, windblown 

dust, and to a lesser extent, fugitive dust. These dust sources are generated mainly from 

Montana and Idaho, with the exception of the Bridger site, where most of the coarse PM 

emissions are generated in Wyoming. These dust sources are a combination of natural and 

human activity, such as construction, mining, unpaved and paved roads, and agriculture. There 

is some contribution from natural fire sources, mainly from Wyoming and Idaho, as well as 

contributions from point sources in Wyoming, Utah and Montana. 

When comparing 2002 and 2018, most figures show increases in fugitive dust and road dust 

mainly due to population growth. Windblown dust remains constant in all figures. 

Figure 5.2.11-1. WEP Potential Contribution to Coarse PM at Yellowstone NP, Grand 

 Teton NP, and Teton Wilderness Area on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% worst visibility days at Yellowstone, the most sizeable coarse PM contributions are 

from dust sources originating in Montana and Idaho. Wyoming is the third largest contributor of 

coarse PM, with slightly less than 50% coming from natural fire sources and the remainder 
81

mainly from dust sources. To a much lesser extent, Utah, Oregon, Washington and Canada also 

contribute coarse PM to the Yellowstone monitoring site. 

Figure 5.2.11-2. WEP Potential Contribution to Coarse PM at North Absaroka Wilderness 

 and Washakie Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Dust sources from Montana, by far, are the largest contributor to coarse PM on the 20% worst 

visibility days at North Absaroka. Idaho and Wyoming are the next largest contributors, 

followed by Canada. 

Figure 5.2.11-3. WEP Potential Contribution to Coarse PM at Bridger Wilderness and 

 Fitzpatrick Wilderness Areas on 20% Worst Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
82

For the 20% worst visibility days at Bridger, Wyoming is the largest contributor of coarse PM, 

followed closely by Idaho, Utah and Montana, respectively. Point and natural fire sources from 

Wyoming comprise approximately one-third of the coarse PM contribution, while dust sources 

make up roughly two-thirds of the contribution. Oregon, Canada, California, Washington and 

Nevada contribute coarse PM to a much lesser extent at this site.

5.2.12 WEP Potential Contribution to Coarse PM on 20% Best Days

Figures 5.2.12-1 through 5.2.12-3 in this section illustrate the contribution of coarse PM to the 

20% best days in Wyoming Class I areas for 2002 and 2018, based on WEP profiles for each 

IMPROVE monitoring site representing the nearest Class I areas.

The figures below show that the profile for coarse PM is dominated by road dust, windblown 

dust, and to a lesser extent, fugitive dust. These dust sources are generated mainly from 

Montana and Idaho, with the exception of the Bridger site, where most of the coarse PM 

emissions are generated in Idaho, Wyoming and Utah, respectively. Montana generates 

approximately one-third of the amount of dust compared to Idaho at the Bridger monitoring site. 

These dust sources are a combination of natural and human activity, such as construction, 

mining, unpaved and paved roads, and agriculture. There is some contribution from natural fire 

sources, mainly from Wyoming and Idaho, as well as smaller contributions from point sources in 

Utah, Wyoming, and Montana. 

When comparing 2002 and 2018, most figures show increases in fugitive dust and road dust 

mainly due to population growth. Windblown dust remains constant in all figures. 

Figure 5.2.12-1. WEP Potential Contribution to Coarse PM at Yellowstone NP, Grand 

 Teton NP, and Teton Wilderness Area on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best visibility days at Yellowstone, the most sizeable coarse PM contributions are 

from dust sources originating in Idaho and Montana. Wyoming is the third largest contributor of 
83

coarse PM, with approximately 50% coming from natural fire sources and 50% from dust 

sources. Utah is the fourth largest contributor, with the majority attributable to dust sources, and 

a smaller amount coming from point sources. To a much lesser extent, Oregon, Canada, Nevada, 

California and Washington also contribute coarse PM to the Yellowstone monitoring site. 

Figure 5.2.12-2. WEP Potential Contribution to Coarse PM at North Absaroka Wilderness 

 and Washakie Wilderness Areas on 20% Best Visibility Days 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Dust sources from Montana and Idaho are the largest contributors to coarse PM on the 20% best 

visibility days at North Absaroka. Wyoming and Utah are the next largest contributors, followed 

by Oregon, Canada and Washington. 
84

Figure 5.2.12-3. WEP Potential Contribution to Coarse PM at Bridger Wilderness and 

 Fitzpatrick Wilderness Areas on 20% Best Visibility Days

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

For the 20% best visibility days at Bridger, Idaho is the largest contributor of coarse PM, 

followed by Wyoming, Utah and Montana, respectively. Dust sources are the dominant 

component of the coarse PM emissions at the Bridger site, followed by natural fire and point 

sources.

5.3 CMAQ 2018 Projected Visibility Conditions

This section summarizes the regional haze improvements projected using the CMAQ model for 

Wyoming’s Class I areas. The CMAQ model was used to estimate 2018 visibility conditions in 

Wyoming and all Western Class I areas, based on emission inputs described in Section 5.1.2 of 

this chapter. The Division relied upon the results of the CMAQ modeling in establishing the 

Reasonable Progress Goals described in Chapter 7. 

These visibility projections were calculated from modeled results by multiplying a speciesspecific relative response factor (RRF) with the baseline monitored result, and then converting to 

extinction and deciview. The RRF is defined as the ratio of future-to-current modeled mass. 

Chapter 7 details how the 2018 projected visibility conditions were used for setting Reasonable 

Progress Goals. Analysis of the WRAP 2018 preliminary reasonable progress modeling runs are 

contained in an August 2009 ENVIRON Memorandum in Chapter 5 of the Wyoming TSD. 

Table 5.3-1 shows the 2018 visibility projections for the 20% worst and best days, compared to 

the 2018 Uniform Rate of Progress (URP) for Wyoming Class I areas (grouped by IMPROVE 

monitoring site). These 2018 projections are shown in deciview, and in the percent of the URP 

achieved by 2018 for the 20% worst days (first shaded column). Also indicated is whether the 

20% best days for 2018 are projected to be under the 2000-2004 baseline (second shaded 

column). 
85

This table shows that Wyoming’s Class I areas are slightly less than half way to meeting the 

2018 URP for the 20% worst days. Section 5.3.1 provides a breakdown by pollutant species to 

analyze the cause of this. For the 20% best days, all Class I areas are under the baseline, and 

thus show no visibility degradation by 2018. 

Table 5.3-1. CMAQ Modeling Results for 20% Worst Days and 20% Best Days for 

 Wyoming Class I Areas

Wyoming Class I Area

20% Worst Days 20% Best Days

2000-04

Baseline

(dv)

2018

URP

Goal 

(dv)

2018

Projected

Visibility

(dv)

% of

2018

URP

Goal

2000-04

Baseline

(dv)

2018

Projected

Visibility

(dv)

2018

Under

Baseline?

Yellowstone National Park

Grand Teton National Park

Teton Wilderness

11.8 10.5 11.2 46% 2.6 2.4 Yes

North Absaroka Wilderness

Washakie Wilderness 11.5 10.4 11.0 45% 2.0 2.0 Yes

Bridger Wilderness

Fitzpatrick Wilderness 11.1 10.0 10.6 45% 2.1 2.0 Yes

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

5.3.1 CMAQ Modeling Breakdown by Pollutant for 20% Worst Days 

As indicated by the 2018 visibility projections using CMAQ modeling, none of the Class I areas 

meet the URP goal for 2018 for the 20% worst days. In order to determine the cause, it is 

necessary to break down these results to identify individual pollutants. The information provided 

below shows the contribution of each pollutant in extinction (Mm-1) to the total extinction level 

for each Class I area. As pointed out earlier in this chapter, it is important to note whether the 

pollutants affecting the modeling are anthropogenic, such as sulfates or nitrates, or the other 

pollutants that are mostly natural in origin (OC, EC, and PM). This assessment is important in 

the determination of reasonable progress, described in Chapter 7. 

Figures 5.3.1-1 through 5.3.1-3 provide a breakdown of individual pollutant contribution (in 

extinction) by showing the glide slope of each pollutant in each Class I area, from the baseline to 

2018, and beyond, for the 20% worst days. Below each figure is a table that shows the 2018 

projections for each pollutant, and whether the projection is under the 2018 URP goal, and the 

percent improvement toward the 2018 URP goal. 

The results of this breakdown by pollutant shows that at all Class I areas, nitrate exceeds or 

meets the 2018 URP goal. For sulfate, while none of the Class I areas meet the 2018 URP goal, 

the improvement is as high as 82% at the Bridger Class I area. Conversely, these tables and 

figures show that organic carbon is the highest contributor to extinction, and projections for 2018 

show very little improvement. Much of the organic carbon can be attributed to fire, of which the 

majority is wildfire, and thus non-anthropogenic in origin. For fine soil there is no progress 

toward the 2018 URP goal because the projected 2018 values are higher than or equal to baseline 

conditions. Chapter 7 provides further discussion related to Reasonable Progress Goal 

demonstration. 
86

Figure 5.3.1-1. Glide Slope by Pollutant on 20% Worst Days for Yellowstone NP, Grand 

 Teton NP, and Teton Wilderness Area

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Table 5.3.1-1. Pollutant Breakdown on 20% Worst Days for Yellowstone NP, Grand Teton 

 NP, and Teton Wilderness Area

Pollutant 

Yellowstone NP, Grand Teton NP, and Teton Wilderness Area

2000-04 

Baseline

(Mm-1)

2018

URP

Goal 

(Mm-1)

2018

Projected

Visibility

(Mm-1)

2064

Natural 

Conditions

(Mm-1)

2018

Under

URP

Goal?

% of

URP

Goal 

Sulfate 4.3 3.4 3.7 0.8 No 67%

Nitrate 1.8 1.5 1.4 0.6 Yes >100%

Organic

Carbon 13.5 11.0 12.9 4.6 No 24% 

Elemental

Carbon 2.5 2.0 2.2 0.4 No 60% 

Fine Soil 1.0 1.0 1.0 1.0 Yes None*

Coarse

Material 2.6 2.7 2.6 3.0 Yes >100% 

Sea Salt 0.0 0.0 0.0 0.0 Yes 100%

*No progress towards URP goal because projected 2018 values are higher than or equal to baseline 

 conditions.

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
87

Figure 5.3.1-2. Glide Slope by Pollutant on 20% Worst Days for North Absaroka and 

 Washakie Wilderness Areas

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Table 5.3.1-2. Pollutant Breakdown on 20% Worst Days for North Absaroka and 

 Washakie Wilderness Area

Pollutant 

North Absaroka and Washakie Wilderness Areas

2000-04 

Baseline

(Mm-1)

2018

URP

Goal 

(Mm-1)

2018

Projected

Visibility

(Mm-1)

2064

Natural 

Conditions

(Mm-1)

2018

Under

URP

Goal?

% of

URP

Goal 

Sulfate 4.9 3.8 4.5 0.8 No 45%

Nitrate 1.6 1.4 1.3 0.8 Yes >100%

Organic

Carbon 11.6 9.8 11.0 4.6 No 33% 

Elemental

Carbon 1.9 1.5 1.6 0.4 No 75% 

Fine Soil 0.9 0.9 1.0 0.9 No None*

Coarse

Material 2.9 3.0 2.9 3.4 Yes >100% 

Sea Salt 0.0 0.0 0.0 0.0 Yes 100%

*No progress towards URP goal because projected 2018 values are higher than or equal to baseline 

 conditions.

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
88

Figure 5.3.1-3. Glide Slope by Pollutant on 20% Worst Days for Bridger and Fitzpatrick

 Wilderness Areas

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

Table 5.3.1-3. Pollutant Breakdown on 20% Worst Days for Bridger and Fitzpatrick

 Wilderness Areas

Pollutant 

Bridger and Fitzpatrick Wilderness Areas

2000-04 

Baseline

(Mm-1)

2018

URP

Goal 

(Mm-1)

2018

Projected

Visibility

(Mm-1)

2064

Natural 

Conditions

(Mm-1)

2018

Under

URP

Goal?

% of

URP

Goal 

Sulfate 5.0 3.9 4.1 0.8 No 82%

Nitrate 1.4 1.3 1.2 0.8 Yes >100%

Organic

Carbon 10.6 9.0 10.3 4.6 No 19% 

Elemental

Carbon 2.0 1.6 1.8 0.4 No 50% 

Fine Soil 1.1 1.1 1.2 1.1 No None*

Coarse

Material 2.5 2.6 2.5 2.7 Yes >100% 

Sea Salt 0.0 0.0 0.0 0.0 Yes 100%

*No progress towards URP goal because projected 2018 values are higher than or equal to baseline 

 conditions.

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
89

CHAPTER 6

BEST AVAILABLE RETROFIT TECHNOLOGY (BART)

6.1 Introduction 

One of the principal elements of Section 169A of the 1977 Clean Air Act Amendments addresses 

the installation of Best Available Retrofit Technology (BART) for certain existing sources of 

pollution. The provision, 169A(b)(2), demonstrates Congress’ intent to focus attention directly 

on pollution from a specific group of existing sources. The U.S. EPA’s Regional Haze Rule 

requires certain emission sources that may reasonably be anticipated to cause or contribute to 

visibility impairment in downwind Class I areas to install BART (see 40 CFR 51.308(e); see also 

64 Fed. Reg. 35714 et seq. (July 1, 1999)). These requirements are intended to reduce emissions 

from certain large sources that, due to age, were exempted from other requirements of the Clean 

Air Act.

BART requirements pertain to 26 specified major point source categories including power 

plants, cement kilns and industrial boilers. To be considered BART-eligible, sources from these 

categories must have the potential to emit 250 tons or more of haze forming pollution and must 

have commenced operation in the 15-year period prior to August 7, 1977. 

In addition to source-by-source command and control BART implementation, EPA has allowed 

for more flexible alternatives if they achieve greater progress toward the State’s visibility goals 

than the standard BART approach. 

On July 1, 1999, the EPA published regulations to address regional haze visibility impairment. 

The regulations required states to address BART requirements for regional haze visibility 

impairment, and allowed nine western states to develop plans that were based on the GCVTC 

recommendations for stationary SO2 sources in lieu of BART. 

In 2000 the Western Regional Air Partnership (WRAP) submitted an Annex to the GCVTC 

recommendations that provided more details regarding the regional SO2 milestones and backstop 

trading program that had been recommended in the GCVTC Report, and included a 

demonstration that the milestones achieved greater reasonable progress than would have been 

achieved by the application of BART in the region. The Annex was approved by EPA in 2003, 

but this approval was later vacated by the DC Circuit Court of Appeals in 2005 due to problems 

with the methodology that was required in the regional haze rule for demonstrating greater 

reasonable progress than BART. 3

On July 6, 2005 EPA revised the Regional Haze Rule in response to the judicial challenges to the 

BART requirements. On October 13, 2006 EPA published additional revisions to address 

alternatives to source-specific BART determinations.

 

3 Center for Energy and Economic Development v. EPA, February 18, 2005; American Corn Growers Association v. 

EPA, May 24, 2002.
90

Five western states (Arizona, New Mexico, Oregon, Utah, and Wyoming) had submitted State 

Implementation Plans (SIPs) in 2003 under 40 CFR 51.309. Four of those states (Arizona, New 

Mexico, Utah, and Wyoming) have updated their SIPs to include new SO2 milestones that are 

based on more recent emission inventories as well as the revised BART requirements in the 

Regional Haze Rule. The fifth state, Oregon, is no longer participating in the program. Details 

on the alternative to the BART program are contained in the 309 SIP submittal to EPA under a 

separate action.

6.2 SO2: Regional SO2 Milestone and Backstop Trading Program 

Wyoming is a §309 state participating in the Regional SO2 Milestone and Backstop Trading 

Program. §308(e)(2) provides states with the option to implement or require participation in an 

emissions trading program or other alternative measure rather than to require sources subject to 

BART to install, operate, and maintain additional control technology to meet an established 

emission limit on a continuous basis. However, the alternate program must achieve greater 

reasonable progress than would be accomplished by installing BART. A demonstration that the 

alternate program can achieve greater reasonable progress is prescribed by §308(e)(2)(i). Since 

the pollutant of concern is SO2, this demonstration has been performed under §309 as part of the 

State Implementation Plan. §309(d)(4)(i) requires that the SO2 milestones established under the 

Plan “...must be shown to provide for greater reasonable progress than would be achieved by 

application of BART pursuant to §51.308(e)(2).” 

Wyoming participated in creating a detailed report entitled Demonstration That the SO2

Milestones Provide Greater Reasonable Progress Than BART covering SO2 emissions from 

all states participating in the Regional SO2 Milestone and Backstop Trading Program. The 

document was submitted to EPA in support of the §309 Wyoming Regional Haze SIP in 

November of 2008. 

As part of the §309 program, participating states, including Wyoming, must submit an annual 

Regional Sulfur Dioxide Emissions and Milestone Report that compares actual emissions to preestablished milestones. Participating states have been filing these reports since 2003. Each year, 

states have been able to demonstrate that actual SO2 emissions are well below the milestones. 

The actual emissions and their respective milestones are shown below: 

Table 6.2-1. Regional Sulfur Dioxide Emissions and Milestone Report Summary

Year

Reported SO2

Emissions

(tons)

3-year Milestone 

Average 

(tons)

2003 330,679 447,383

2004 337,970 448,259

2005 304,591 446,903

2006 279,134 420,194

2007 273,663 420,637

In addition to demonstrating successful SO2 emission reductions, §309 states have also relied on 

visibility modeling conducted by the WRAP to demonstrate improvement at Class I areas. The 
91

complete modeling demonstration showing deciview values was included as part of the visibility 

improvement section of the §309 SIP, but the SO2 portion of the demonstration has been 

included as Table 6.2-2 to underscore the improvements associated with SO2 reductions. 

Table 6.2-2. Visibility - Sulfate Extinction Only

Class I Area Monitor

(Class I Areas Represented)

20% Worst Visibility Days

(Monthly Average, Mm-1)

20% Best Visibility Days

(Monthly Average, Mm-1)

2018 1

Base Case 

(Base 18b)

2018 2

Preliminary

Reasonable 

Progress Case

(PRP18a)

2018 1

Base Case 

(Base 18b)

2018 2

Preliminary

Reasonable 

Progress Case

(PRP18a)

Bridger, WY

(Bridger WA and Fitzpatrick WA) 5.2 4.3 1.6 1.3 

North Absaroka, WY

(North Absaroka WA and Washakie WA) 4.8 4.5 1.1 1.1 

Yellowstone, WY

(Yellowstone NP, Grand Teton NP and Teton WA) 4.3 3.9 1.6 1.4 

Badlands, SD 17.8 16.0 3.5 3.1

Wind Cave, SD 13.0 12.1 2.7 2.5

Mount Zirkel, CO

(Mt. Zirkel WA and Rawah WA) 4.6 4.1 1.4 1.3 

Rocky Mountain, CO 6.8 6.2 1.3 1.1

Gates of the Mountains, MT 5.3 5.1 1.0 1.0

UL Bend, MT 9.7 9.6 1.8 1.7

Craters of the Moon, ID 5.8 5.5 1.5 1.5

Sawtooth, ID 3.0 2.8 1.2 1.1

Canyonlands, UT

(Canyonlands NP and Arches NP) 5.4 4.8 2.1 1.9 

Capitol Reef, UT 5.7 5.4 1.9 1.8 1 Represents 2018 Base Case growth plus all established controls as of Dec. 2004. No BART or SO2 Milestone assumptions were included. 2 Represents 2018 Preliminary Reasonable Progress growth estimates and established SO2 limits (including milestone levels established at

 the time of the model run).

All Class I areas in the surrounding states show a projected visibility improvement for 2018 with 

respect to SO2 on the worst days and no degradation on the best days. More discussion on the 

visibility improvement of the §309 program can be found in the Wyoming §309 Regional Haze 

SIP revision submitted to EPA in November 2008. 

Therefore, in accordance with §308(e)(2), Wyoming’s §309 Regional Haze SIP, and WAQSR 

Chapter 6, Section 9, sources will not be required to install BART controls to meet an SO2 

emission limit. Instead, sources will be required to participate in the Regional SO2 Milestone 

and Backstop Trading Program authorized under Chapter 14 of the WAQSR. 

The remainder of this section, therefore, focuses on how Wyoming has satisfied the BART 

requirements with respect to NOx and PM in EPA’s Regional Haze Rule. Wyoming’s review 

process is described and a list of BART-eligible sources is provided. A list of sources that are 

subject to BART is also provided, along with the requisite modeling analysis approach and 

justification. Wyoming made its BART determinations using the methodology in EPA’s 

Guidelines for BART Determinations Under the Regional Haze Rule, 40 Fed. Reg. 39104 et seq. 
92

(July 6, 2005) (hereinafter “Appendix Y”), and the Wyoming Air Quality Standards and 

Regulations (WAQSR) Chapter 6, Permitting Requirements, Section 9, Best available retrofit 

technology (BART). EPA’s Guidelines for BART Determinations and Chapter 6, Section 9 of 

the WAQSR can be found in Chapter 6 of the Wyoming TSD.

6.3 Overview of Wyoming’s BART Regulation 

Wyoming’s Environmental Quality Council approved a State-only BART regulation (Chapter 6, 

Permitting Requirements, Section 9, Best available retrofit technology (BART)) on October 10, 

2006, that became effective in December 2006. The provisions of the regulation required 

BART-subject sources to submit an application, according to a schedule determined by the Air 

Quality Division, for a BART determination. 

Wyoming’s BART Rule is based largely upon EPA’s BART Rule and related Appendix Y, 

which includes procedures to be followed when making BART determinations for individual 

sources. States are only required to follow Appendix Y procedures for sources which are electric 

generating units (EGUs) with greater than 750 MW generating capacity. EPA’s BART Rule has 

no specific requirements for conducting BART determinations for sources that are not electric 

generating plants with greater than 750 MW capacities. EPA encourages states to use its 

guidelines for all source categories, but states are not required to do so. 

6.4 SIP BART Requirements From EPA’s Regional Haze Rule

The following sections address the SIP elements relative to BART contained in EPA’s Regional 

Haze Rule. Section numbers refer to provisions in section 308(e), the BART provision of the 

Regional Haze Rule.

308(e)(1)(i) - A list of all BART-eligible sources within the State.

The U.S. EPA regulations for best available retrofit technology (BART) are contained in 40 CFR 

part 51, Appendix Y, published July 6, 2005 in the Federal Register, and provide the guidelines 

for BART determinations. Section II of Appendix Y discusses a three-step procedure for 

identifying BART-eligible sources. A source was BART-eligible if it 1) belonged to one of the 

26 listed categories, 2) was “in existence” on August 7, 1977, but not “in operation” before 

August 7, 1962, and 3) had the potential to emit greater than 250 tons per year of any single 

visibility impairing pollutant. If a facility met all three criteria mentioned, then a screening 

analysis was used to determine if it was “subject to BART”, per Section III of Appendix Y. 

Using Appendix Y as a guideline, the State of Wyoming determined that there were fourteen 

(14) facilities with BART-eligible emission units. These facilities are listed below:

PacifiCorp - Jim Bridger General Chemical

PacifiCorp - Naughton P4 Production 

FMC - Granger OCI Wyoming 

FMC - Green River Dyno Nobel 

Basin Electric - Laramie River Sinclair - Casper Refinery
93

 

PacifiCorp - Wyodak Black Hills - Neil Simpson 1

PacifiCorp - Dave Johnston Sinclair - Sinclair Refinery

The Division completed a BART screening analysis on the fourteen facilities to determine which 

facilities had a significant impact on visibility in Class I areas in Wyoming, South Dakota, and 

Colorado. 

As specified in the Division’s BART Air Modeling Protocol dated March 2006 (see Chapter 6 of 

the Wyoming TSD), a source was deemed to produce a significant impact to visibility on a Class 

I area if the source had a modeled impact to visibility value greater than 0.5 deciview (dv) to 

determine a daily maximum change in visibility (Δdv) value for each Class I area and year of 

meteorological data. The visibility impact threshold to determine BART sources is a 98th

percentile change in visibility (Δdv) of 0.5 dv above background conditions. Therefore, if the 8th

highest Δdv value was equal to or greater than 0.5 dv, the source was considered to cause or 

contribute to visibility impairment in the subject Class I area, and therefore was “subject to 

BART”. However, if the 8th highest value for all three years at each Class I area in a given 

domain was less than 0.5 dv, the source was not subject to BART. Using these criteria, the 

fourteen facilities were screened for BART subjectivity. The BART Facilities Emissions 

Inventory in Chapter 6 of the Wyoming TSD details the emission units at the BART-eligible 

sources. Screening results, which provide the maximum change in visibility, number of days 

>0.5 dv, and 8th high values, are summarized in the WY BART Screening Analysis Results and 

the WY BART Screening Analysis Results DV Frequency, which can also be found in Chapter 6 

of the Wyoming TSD. After evaluating the results of the screening analysis, the following 

facilities were found to be subject to BART or not subject to BART. 

Subject to BART Not Subject to BART 

PacifiCorp - Jim Bridger P4 Production 

PacifiCorp - Naughton OCI Wyoming 

FMC - Granger Dyno Nobel 

FMC - Green River Sinclair - Casper Refinery

Basin Electric - Laramie River Black Hills - Neil Simpson 1

PacifiCorp - Wyodak Sinclair - Sinclair Refinery

PacifiCorp - Dave Johnston 

General Chemical

308(e)(1)(ii) - A determination of BART for each BART-eligible source in the State that emits 

any air pollutant which may reasonably be anticipated to cause or contribute to any impairment 

of visibility in any mandatory Class I Federal area. All such sources are subject to BART.

The following table summarizes the Division’s BART determinations for sources that cause or 

contribute to visibility impairment in Class I areas. These BART determinations are part of this 

Regional Haze SIP that will be submitted to EPA.
94

Table 6.4-1. BART Determinations for Wyoming Sources 

Unit NOx Control 

Type

NOx Emission 

Limit

Particulate Control

Type

PM10 Emission 

Limit (1) 

Basin Electric – Laramie (2)

River Unit 1 (550 MW)

LNB + OFA 0.21 lb/MMBtu 

(30-day rolling)

ESP 0.030 lb/MMBtu

Basin Electric – Laramie (2)

River Unit 2 (550 MW)

LNB + OFA 0.21 lb/MMBtu 

(30-day rolling)

ESP 0.030 lb/MMBtu

Basin Electric – Laramie (2)

River Unit 3 (550 MW)

LNB + OFA 0.21 lb/MMBtu 

(30-day rolling)

ESP 0.030 lb/MMBtu

FMC Wyoming – Granger 14 

(358.5 MMBtu)

n/a n/a n/a n/a

FMC Wyoming – Granger 15 

(358.5 MMBtu)

n/a n/a n/a n/a

FMC Wyoming – Westvaco 

NS-1A 

(887 MMBtu)

LNB + OFA 0.35 lb/MMBtu 

(30-day rolling)

ESP 0.05 lb/MMBtu

FMC Wyoming – Westvaco 

NS-1B 

(887 MMBtu)

LNB + OFA 0.35 lb/MMBtu 

(30-day rolling)

ESP 0.05 lb/MMBtu

FMC Wyoming – Westvaco 

PH-3 

(333.6 MMBtu)

n/a n/a n/a n/a

General Chemical – Green 

River GR-2-L 

(534 lb/MMBtu)

LNB + SOFA

or equivalent 

technology

0.28 lb/MMBtu 

(30-day rolling)

ESP 0.09 lb/MMBtu

General Chemical – Green 

River GR-3-W 

(880 lb/MMBtu)

LNB + SOFA

or equivalent 

technology

 0.28 lb/MMBtu 

(30-day rolling)

ESP 0.09 lb/MMBtu

PacifiCorp – Dave Johnston 

Unit 3 (230 MW)

LNB + OFA 0.28 lb/MMBtu

(30-day rolling)

Fabric Filter 0.015 lb/MMBtu

PacifiCorp – Dave Johnston 

Unit 4 (330 MW)

LNB + OFA 0.15 lb/MMBtu 

(30-day rolling)

Fabric Filter 0.015 lb/MMBtu

PacifiCorp – Jim Bridger 

Unit 1 (530 MW)

LNB + OFA 0.26 lb/MMBtu 

(30-day rolling)

ESP + FGC 0.030 lb/MMBtu

PacifiCorp – Jim Bridger 

Unit 2 (530 MW) 

LNB + OFA 0.26 lb/MMBtu 

(30-day rolling)

ESP + FGC 0.030 lb/MMBtu

PacifiCorp – Jim Bridger 

Unit 3 (530 MW)

LNB + OFA 0.26 lb/MMBtu 

(30-day rolling)

ESP + FGC 0.030 lb/MMBtu

PacifiCorp – Jim Bridger 

Unit 4 (530 MW) 

LNB + OFA 0.26 lb/MMBtu 

(30-day rolling)

ESP + FGC 0.030 lb/MMBtu

PacifiCorp – Naughton Unit 1 

(160 MW) 

LNB + OFA 0.26 lb/MMBtu 

(30-day rolling)

ESP + FGC 0.040 lb/MMBtu

PacifiCorp – Naughton Unit 2 

(210 MW) 

LNB + OFA 0.26 lb/MMBtu 

(30-day rolling)

ESP + FGC 0.040 lb/MMBtu

PacifiCorp – Naughton Unit 3 

(330 MW) 

LNB + OFA + 

SCR

0.07 lb/MMBtu 

(30-day rolling)

Fabric Filter 0.015 lb/MMBtu

PacifiCorp – Wyodak Unit 1 

(335 MW)

LNB + OFA 0.23 lb/MMBtu 

(30-day rolling)

Fabric Filter 0.015 lb/MMBtu

(1) Filterable portion only; (2) These emission limits reflect condition 7c in the Settlement Agreement between DEQ/AQD and 

Basin Electric, EQC Docket No. 10-2802.

ESP = electrostatic precipitator; FGC = flue gas conditioning; LNB = low NOx burners; n/a = not subject to BART; 

OFA = overfire air; SCR = selective catalytic reduction; SOFA = separated overfire air

 

 
95

I. The Five-Factor Analysis

308(e)(1)(ii)(A) - The determination of BART must be based on an analysis of the best system of 

continuous emission control technology available and associated emission reductions achievable 

for each BART-eligible source that is subject to BART within the State. In this analysis, the State 

must take into consideration the technology available, the costs of compliance, the energy and 

non-air quality environmental impacts of compliance, any pollution control equipment in use at 

the source, the remaining useful life of the source, and the degree of improvement in visibility 

which may reasonably be anticipated to result from the use of such technology.

Details of how each of these factors is taken into consideration during the BART determination 

process are found below in the Facility Analysis section. 

II. Compliance With Appendix Y 

308(e)(1)(ii)(B) - The determination of BART for fossil-fuel fired power plants having a total 

generating capacity greater than 750 megawatts must be made pursuant to the guidelines in 

appendix Y of this part (Guidelines for BART Determinations Under the Regional Haze Rule).

EPA’s guidelines are only mandatory with respect to plants greater than 750 megawatts (see 70 

Fed. Reg. at 39108, 39131). EPA does not require that the guidelines be followed for other 

source types (see id.). In fact, EPA concluded that it “would not be appropriate for EPA to 

require states to use the guidelines in making BART determinations for other categories of 

sources” (id. at 39108). States thus “retain the discretion to adopt approaches that differ from the 

guidelines” (id. at 39158). The following fossil-fuel fired power plants have a total generating 

capacity greater than 750 megawatts:

Basin Electric Power Cooperative - Laramie River (1,650 MW) 

PacifiCorp - Dave Johnston (772 MW) 

PacifiCorp - Jim Bridger (2,120 MW) 

EPA’s guidelines in Appendix Y were followed for the three facilities listed above. Details of 

how the guidelines were followed are found in the Facility Analysis section below. 

III. Expeditious Installation and Operation of BART 

308(e)(1)(iv) - A requirement that each source subject to BART be required to install and 

operate BART as expeditiously as practicable, but in no event later than 5 years after approval 

of the implementation plan revision.

This requirement is addressed in Wyoming’s BART Rule and compliance with this requirement 

is discussed in the specific Facility Analysis for each source below. 

IV. Proper Maintenance and Operation of Control Equipment 

308(e)(1)(v) - A requirement that each source subject to BART maintain the control equipment 

required by this subpart and establish procedures to ensure such equipment is properly operated 

and maintained.
96

This requirement is addressed in Wyoming’s BART Rule and compliance with this requirement 

is discussed in Section V. 

V. Monitoring and Recordkeeping Requirements

Startup Notification: The owner or operator shall furnish the Administrator written notification 

of: (i) the anticipated date of initial startup not more than 60 days or less than 30 days prior to 

such date, and; (ii) the actual date of initial startup within 15 days after such date in accordance 

with Chapter 6, Section 2(i) of the WAQSR. 

Chapter 6, Section 3 Operating Permit: The owner or operator shall modify their Operating 

Permit in accordance with Chapter 6, Section 9(e)(vi) and Chapter 6, Section 3 of the WAQSR. 

Initial Performance Tests: The owner or operator shall conduct initial performance tests in 

accordance with Chapter 6, Section 2(j) of the WAQSR, within 30 days of achieving a maximum 

design rate but not later than 90 days following initial startup, and a written report of the results 

shall be submitted. If a maximum design rate is not achieved within 90 days of startup, the Air 

Quality Division Administrator may require testing be done at the rate achieved and again when 

a maximum rate is achieved.

Periodic Particulate Performance Testing: Particulate testing shall be conducted annually, or 

more frequently as specified by the Air Quality Division Administrator following the test 

methods specified in this section. 

Test Methods: 

NOx Emissions - Compliance with the NOx 30-day rolling average shall be 

determined using a continuous emissions monitoring system (CEMS) certified in 

accordance with 40 CFR part 60 (Non-EGUs) or 40 CFR part 75 (EGUs).

PM/PM10 Emissions - Testing shall follow 40 CFR 60.46 and EPA Reference 

Test Methods 1-4 and 5. 

Prior to any testing, a test protocol shall be submitted to the Division for approval, 

at least 30 days prior to testing. Notification should be provided to the Division at 

least 15 days prior to any testing. Results of the tests shall be submitted to the 

Division office within 45 days of completing the tests.

NOx CEM Requirements: At all times after the compliance deadline specified in Section 6.5, the 

owner/operator of each BART unit shall maintain, calibrate, and operate a CEMS in full 

compliance with the requirements found at 40 CFR part 60 (Non-EGUs) or 40 CFR part 75 

(EGUs), to accurately measure NOx, diluent (CO2 or O2), and stack gas volumetric flow rate 

from each BART unit. The CEMS shall be used to determine compliance with the NOx BART 

emission limits for each BART unit.

BART Limits: The NOx limits in terms of lb/MMBtu, lb/hr and tpy apply at all times, including 

periods of startup and shutdown. The PM/PM10 limits in terms of lb/hr and tpy apply at all 
97

times, including periods of startup and shutdown. The PM/PM10 limits in terms of lb/MMBtu 

apply at all times except during startup. Emissions in excess of the BART limits due to 

unavoidable equipment malfunction are not considered a violation if the event is covered under 

Chapter 1, Section 5 of the WAQSR. The burden of proof is on the owner or operator of the 

source to provide sufficient information to demonstrate that an unavoidable equipment 

malfunction has occurred.

BART NOx Limits: lb/MMBtu and lb/hr shall be 30-day rolling averages and the tpy shall be a 

calendar year total.

a. Exceedances of the NOx limits shall be defined as follows:

i. Any 30-day rolling average which exceeds the lb/MMBtu NOx limits as 

calculated using the following formula:

n

C

E

n

h

h

avg

∑= = 1

)(

 Where:

Eavg = Weighted 30-day rolling average emission rate (lb/MMBtu).

C = 1-hour average emission rate (lb/MMBtu) for hour “h” calculated using 

valid data from the CEM equipment certified and operated in accordance 

with part 75 and the procedures in 40 CFR part 60, Appendix A, Method 

19. V alid data shall meet the requirements of WAQSR, Chapter 5, 

Section 2(j). Valid data shall not include data substituted using the 

missing data procedure in Subpart D of part 75, nor shall the data have 

been bias adjusted according to the procedures of part 75. 

n = The number of unit operating hours in the last 30 successive boiler 

operating days with valid emissions data meeting the requirements of 

WAQSR, Chapter 5, Section 2(j). A “boiler operating day” shall be 

defined as any 24-hour period between 12:00 midnight and the following 

midnight during which any fuel is combusted at any time at the steam 

generating unit. 

ii. Any 30-day rolling average which exceeds the lb/hr NOx limits as calculated 

using the following formula: 

n

C

E

n

h

h

avg

∑= = 1

)(

 Where:

Eavg = Weighted 30-day rolling average emission rate (lb/hr).
98

C = 1-hour average emission rate (lb/hr) for hour “h” calculated using valid 

data (output concentration and average hourly volumetric flowrate) from 

the CEM equipment certified and operated in accordance with part 75. 

Valid data shall meet the requirements of WAQSR, Chapter 5, Section 

2(j). Valid data shall not include data substituted using the missing data 

procedure in Subpart D of part 75, nor shall the data have been bias 

adjusted according to the procedures of part 75. 

n = The number of unit operating hours in the last 30 successive boiler 

operating days with valid emissions data meeting the requirements of 

WAQSR, Chapter 5, Section 2(j). A “boiler operating day” shall be 

defined as any 24-hour period between 12:00 midnight and the following 

midnight during which any fuel is combusted at any time at the steam 

generating unit. 

iii. Any 12-month rolling emission rate which exceeds the tpy NOx limit as 

calculated using the following formula:

( )

000,2

1

∑= = h

C h

E

Where:

C = 1-hour average emission rate (lb/hr) for hour “h” calculated using 

data from the CEM equipment required by 40 CFR part 75. For

monitoring data not meeting the requirements of WAQSR, Chapter 

5, Section 2(j), Basin Electric shall provide substituted data for an 

emissions unit according to the missing data procedures of 40 CFR 

part 75 during any period of time that there is not monitoring data. 

E = 12-month rolling emission rate (tpy).

iv. Any calendar year total calculated using valid data (output concentration 

and average hourly volumetric flow rate) from the CEM equipment and 

operating data from the boiler which exceeds the tpy NOx limit. Valid 

data shall meet the requirements of WAQSR Chapter 5, Section 2(j). For 

EGUs, the owner or operator shall use EPA’s Clean Air Markets reporting 

program to convert the monitoring system data to annual emissions. The 

owner or operator shall provide substituted data according to the missing 

data procedures of 40 CFR part 75 during any period of time that there is 

no monitoring data. 

BART PM/PM10 Limits: lb/MMBtu and lb/hr limits shall be a 1-hour average based on the 

average of three performance tests. Compliance with lb/MMBtu and lb/hr shall be determined 

from the initial and annual performance tests. Annual emissions (tpy) shall be a calendar year 

total calculated using the lb/MMBtu performance test result and boiler operating data.
99

Recordkeeping and Reporting: The owner or operator shall comply with all reporting and 

recordkeeping requirements as specified in WAQSR Chapter 5, Section 2(g) and 40 CFR part 60, 

Subpart D. All excess emissions shall be reported using the procedures and reporting format 

specified in WAQSR Chapter 5, Section 2(g). Records shall be maintained for a period of at 

least five (5) years and shall be made available to the Division upon request. 

6.5 Facility Analysis

Note that the following discussions of BART determinations are based upon proposed BART 

permit conditions that are undergoing public review and comment. Following issuance of final 

BART permits as required by Chapter 6, Section 9 of the WAQSR, the State of Wyoming will 

supplement the SIP with revised descriptions of the BART determinations, if necessary. 

6.5.1 FMC Wyoming Corp. - Granger Facility

The State of Wyoming performed a refined CALPUFF visibility modeling analysis for the two 

BART-eligible units at the FMC Wyoming Granger Facility, and demonstrated that the predicted 

98th percentile impacts at Bridger WA and Fitzpatrick WA would be below 0.5 dv for all 

meteorological periods modeled. This modeling used higher-resolution meteorological data as 

compared to the data used by the Division for the initial screening modeling that identified the 

facility as “subject” to BART. A single source is exempt from BART if the modeled 98th

percentile change is less than 0.5 dv at all Class I areas for each year modeled, in accordance 

with Chapter 6, Section 9(d)(i)(C) of the WAQSR. Therefore, the State of Wyoming has 

determined that the two BART-eligible units at the FMC Wyoming Granger Facility are not 

subject to BART. 

6.5.2 FMC Wyoming Corp. - Green River - Westvaco Facility

I. The Five-Factor Analysis

After considering (1) the costs of compliance, (2) the energy and non-air quality environmental 

impacts of compliance, (3) any pollution equipment in use or in existence at the source, (4) the 

remaining useful life of the source, and (5) the degree of improvement in visibility (all five 

statutory factors) from each proposed control technology, the Division determined BART for 

NOx and PM10 emitted from two units at the Westvaco Facility. The State of Wyoming 

concluded that a third unit at the facility, a gas-fired boiler, was not a significant contributor to 

regional haze and a BART determination was not made for that source. 

For control of NOx emissions, the State of Wyoming requires that FMC install and operate low 

NOx burners (LNB) with enhanced overfire air (OFA) as BART for boilers NS-1A and NS-1B. 

The use of LNB and enhanced OFA will result in a 1,360-ton reduction in annual NOx emissions 

from each boiler. LNB/OFA on boilers NS-1A and NS-1B is cost effective, with an average cost 

effectiveness of $304 per ton of NOx removed for each unit over a twenty-year operational life. 

Combustion control using LNB/OFA does not require non-air quality environmental mitigation 

for the use of chemical reagents (i.e., ammonia or urea) and there is a minimal energy impact. 
100

For control of PM/PM10 emissions, the State of Wyoming requires that FMC utilize the existing 

ESPs as BART for boilers NS-1A and NS-1B. 

Visibility impacts were addressed in a comprehensive visibility modeling analysis covering three 

visibility impairing pollutants and associated control options. The cumulative 3-year averaged 

visibility improvement from the baseline across Bridger WA and Fitzpatrick WA achieved with 

LNB/OFA (based on the 98th percentile modeled results) was 0.2 Δdv from each of the two 

boilers. 

The State of Wyoming considers the BART-determined permit limit to be equivalent to the

control effectiveness of a control technology. The limit is based on continuous compliance when 

the control equipment is well maintained and operated in a manner consistent with good air 

pollution control practices for minimizing emissions. 

Unit-by-unit BART determinations for NOx and PM/PM10: 

Units Pollutant Control Type lb/MMBtu lb/hr tpy 

NS-1A 

NOx LNB/OFA 0.35 (30-day rolling) 284.0 (30-day rolling) 1244.0 

PM/PM10

(a) ESP 0.05 45.0 197.0 

NS-1B 

NOx LNB/OFA 0.35 (30-day rolling) 284.0 (30-day rolling) 1244.0 

PM/PM10

(a) ESP 0.05 45.0 197.0 

(a) Filterable portion only

ESP = electrostatic precipitator

LNB = low NOx burners

OFA = overfire air

III. Expeditious Installation and Operation of BART 

The State of Wyoming requires that FMC install and operate new LNB with enhanced overfire 

air on boilers NS-1A and NS-1B to achieve the BART emissions limits for NOx. Installation of 

LNB and enhanced overfire air has been completed. LNB with OFA will continue to operate on 

boilers NS-1A and NS-1B. The State of Wyoming requires that FMC continue the use of the 

existing ESPs on boilers NS-1A and NS-1B to achieve the BART emissions limits for PM/PM10. 

Initial performance tests for NOx and PM/PM10 have been completed for both boilers. NOx and 

PM/PM10 compliance deadlines for both boilers was on or before October 17, 2009. 

IV. Proper Maintenance and Operation of Control Equipment 

The State of Wyoming requires that FMC follow the monitoring and recordkeeping requirements 

of Section 6.4 V. to ensure proper maintenance and operation of control equipment. 

6.5.3 General Chemical - Green River Works

I. The Five-Factor Analysis

After considering (1) the costs of compliance, (2) the energy and non-air quality environmental 

impacts of compliance, (3) any pollution equipment in use or in existence at the source, (4) the 
101

remaining useful life of the source, and (5) the degree of improvement in visibility (all five 

statutory factors) from each proposed control technology, the Division determined BART for 

NOx and PM10 emitted from the two boilers at Green River Works. 

For control of NOx emissions, the State of Wyoming requires that General Chemical install and 

operate LNB and SOFA or an equivalent performing control technology as BART for boilers C 

and D. The use of LNB and SOFA will result in a 512-ton reduction from baseline for Boiler C 

and a 737-ton reduction from baseline for Boiler D. LNB and SOFA on boilers C and D is cost 

effective, with an average cost effectiveness of $1,280-1,480 per ton of NOx removed for each 

unit over a twenty-year operational life. Combustion control using LNB and OFA does not 

require non-air quality environmental mitigation for the use of chemical reagents (i.e., ammonia 

or urea) and there is a minimal energy impact. Affording General Chemical the option to install 

an equivalent performing control technology does not change the basis of the BART 

determination as the BART determination is made based on currently available controls (e.g., 

existing LNB with new SOFA, SNCR, SCR), which were all deemed reasonable. Allowing the 

company to install an equivalent performing technology provides additional flexibility to control 

emissions to the specified BART levels, presumably in the most cost-effective manner. 

For control of PM/PM10 emissions, the State of Wyoming requires that General Chemical utilize 

the existing ESPs as BART for boilers C and D. 

Visibility impacts were addressed in a comprehensive visibility modeling analysis covering three 

visibility impairing pollutants and associated control options. The cumulative 3-year averaged 

visibility improvement from the baseline across Bridger WA and Fitzpatrick WA achieved with 

LNB and OFA (based on the 98th percentile modeled results) was 0.41 Δdv from the two boilers. 

The State of Wyoming considers the BART-determined permit limit to be equivalent to the 

control effectiveness of a control technology. The limit is based on continuous compliance when 

the control equipment is well maintained and operated in a manner consistent with good air 

pollution control practices for minimizing emissions. 

Unit-by-unit BART determinations for NOx and PM/PM10: 

Units Pollutant Control Type lb/MMBtu lb/hr tpy 

C 

NOx 

LNB/SOFA or

equivalent 

technology 

0.28 (30-day rolling) 149.5 (30-day rolling) 654.9 

PM/PM10

(a) ESP 0.09 50 219.0 

D 

NOx 

LNB/SOFA or

equivalent 

technology

0.28 (30-day rolling) 246.4 (30-day rolling) 1,079.2 

PM/PM10

(a) ESP 0.09 80 350.4 

(a) Filterable portion only

ESP = electrostatic precipitator

LNB = low NOx burners

SOFA = separated overfire air
102

III. Expeditious Installation and Operation of BART 

The State of Wyoming requires that General Chemical install and operate low NOx burners with 

SOFA or equivalent performing technology on boilers C and D, in accordance with the 

Division’s BART determination, and conduct the required initial performance tests to 

demonstrate compliance as expeditiously as practicable, but no later than five years after EPA 

approval of the state implementation plan revision. The State of Wyoming requires that General 

Chemical continue the use of the existing ESPs on boilers C and D to achieve the BART 

emissions limits. Initial performance tests for PM/PM10 have been completed for both boilers. 

The PM/PM10 compliance deadline for both boilers was on or before November 11, 2009. 

IV. Proper Maintenance and Operation of Control Equipment 

The State of Wyoming requires that General Chemical follow the monitoring and recordkeeping 

requirements of Section 6.4 V. to ensure proper maintenance and operation of control equipment. 

6.5.4 PacifiCorp - Jim Bridger Power Plant

I. The Five-Factor Analysis

After considering (1) the costs of compliance, (2) the energy and non-air quality environmental 

impacts of compliance, (3) any pollution equipment in use or in existence at the source, (4) the 

remaining useful life of the source, and (5) the degree of improvement in visibility (all five 

statutory factors) from each proposed control technology, the Division determined BART for 

NOx and PM/PM10 emitted from the four units subject to BART at the Jim Bridger Power Plant. 

In addition to the five-factor analysis, the Division also considered the unique situation 

PacifiCorp is in since they own and operate 19 coal-fired generating units in the West. The 

Division believes that the size of PacifiCorp’s fleet of coal-fired units presents unique challenges 

when reviewing costs, timing of installations, customer needs, and state regulatory commission 

requirements. Information has been supplied by PacifiCorp elaborating on additional factors to 

be considered in PacifiCorp’s BART determination (see “PacifiCorp’s Emissions Reductions 

Plan” in Chapter 6 of the Wyoming TSD). 

For control of NOx emissions, the State of Wyoming requires that PacifiCorp install and operate 

LNB with separated OFA as BART for Units 1 through 4. Annual NOx emission reductions 

from LNB with separated OFA on Units 1, 3, and 4 are 4,493 tons per unit for a total annual 

reduction at the Jim Bridger Power Plant of 13,479 tons per year. There are no NOx reductions 

from Unit 2 as LNB separated OFA is baseline for the unit. 

LNB with separated OFA on Units 1, 3, and 4 is cost effective, with an average cost 

effectiveness of $255 per ton of NOx removed for each unit over a twenty-year operational life. 

LNB with separated OFA on Unit 2 did not require any additional capital cost or annual O&M 

cost. Combustion control using LNB with separated OFA does not require non-air quality 

environmental mitigation for the use of chemical reagents (i.e., ammonia or urea) and there is a 

minimal energy impact. 
103

For control of PM/PM10 emissions, the State of Wyoming requires that PacifiCorp utilize the 

existing electrostatic precipitators (ESPs) with the addition of flue gas conditioning (FGC) as 

BART for Units 1-4. The control technology is cost effective for each unit, with costs per ton 

removed of $1,544 for Unit 1, $526 for Unit 2, and $857 for Unit 3. Unit 4 does not require 

additional capital cost. No negative non-air environmental impacts are anticipated from the use 

of the existing ESPs with FGC. 

Visibility impacts were addressed in a comprehensive visibility modeling analysis covering three 

visibility impairing pollutants and associated control options. The cumulative 3-year averaged 

98th percentile visibility improvement from the baseline across the three Class I areas (Bridger, 

Fitzpatrick, and Mt. Zirkel wilderness areas) achieved with LNB with separated OFA, upgraded 

wet FGD, and FGC for enhanced ESP control was 1.070 Δdv from Unit 1, 0.199 Δdv from Unit 

2, 1.068 Δdv from Unit 3, and 0.892 Δdv from Unit 4. While the visibility improvement 

attributable to the installation of FGC on existing ESPs can’t be directly determined from the 

visibility modeling, the Division does not anticipate the contribution from PM to be significant 

when compared to the contributions from NOx and SO2. 

The State of Wyoming considers the BART-determined permit limit to be equivalent to the

control effectiveness of a control technology. The limit is based on continuous compliance when 

the control equipment is well maintained and operated in a manner consistent with good air 

pollution control practices for minimizing emissions. 

Unit-by-unit BART determinations for NOx and PM/PM10: 

Units Pollutant Control Type lb/MMBtu lb/hr tpy 

1, 2, 3, & 4 NOx LNB/OFA 0.26 (30-day rolling) 1,560 (30-day rolling) 6,833 

1, 2, 3, & 4 PM/PM10 

(a) ESP + FGC 0.030 180 788 

(a) Filterable portion only

ESP = electrostatic precipitator

FGC = flue gas conditioning

LNB = low NOx burners

OFA = overfire air

III. Expeditious Installation and Operation of BART 

The State of Wyoming requires that PacifiCorp install and operate new LNB with separated OFA 

on Unit 1, in accordance with the Division’s BART determination, and conduct the required 

initial performance tests to demonstrate compliance as expeditiously as practicable, but no later 

than five years after EPA approval of the state implementation plan revision. Installation of 

LNB and separated OFA has been completed and initial performance tests have been completed

on Units 2, 3, and 4. The NOx compliance deadline for Units 2-4 was on or before March 31, 

2010. With respect to particulate matter, the State of Wyoming requires that PacifiCorp continue 

the use of the existing ESPs on Units 1 through 4 with FGC to achieve the BART emissions 

limits. Initial performance tests have been conducted and the PM/PM10 compliance deadline for 

Units 1-4 was on or before March 31, 2010. 
104

IV. Proper Maintenance and Operation of Control Equipment 

The State of Wyoming requires that PacifiCorp conduct initial NOx performance tests on Unit 1, 

after the installation of LNB and separated OFA, within 30 days of achieving a maximum design 

rate, but not later than 90 days following initial start-up. If a maximum design rate is not 

achieved within 90 days of start-up, the AQD Administrator may require testing be done at the 

rate achieved and again when a maximum rate is achieved. A test protocol shall be submitted for 

Division approval prior to testing and a written report of the test results shall be submitted to the 

Division. Testing required by the WAQSR Chapter 6, Section 3 operating permit may be 

submitted to satisfy the testing required.

The State of Wyoming requires that PacifiCorp follow the monitoring and recordkeeping 

requirements of Section 6.4 V. to ensure proper maintenance and operation of control equipment. 

6.5.5 PacifiCorp - Dave Johnston Power Plant 

I. The Five-Factor Analysis

After considering (1) the costs of compliance, (2) the energy and non-air quality environmental 

impacts of compliance, (3) any pollution equipment in use or in existence at the source, (4) the 

remaining useful life of the source, and (5) the degree of improvement in visibility (all five 

statutory factors) from each proposed control technology, the Division determined BART for 

NOx and PM10 emitted from the two units subject to BART at the Dave Johnston Power Plant. 

For control of NOx emissions, the State of Wyoming requires that PacifiCorp install and operate 

LNB with advanced OFA as BART for Units 3 and 4. The State of Wyoming will require a NOx

control level of 0.28 lb/MMBtu on a 30-day rolling average, below EPA’s applicable 

presumptive limit of 0.45 lb/MMBtu for cell-fired boilers burning subbituminous coal, for Unit 

3. For Unit 4, the State of Wyoming will require a NOx control level of 0.15 lb/MMBtu on a 30-

day rolling average, equal to EPA’s applicable presumptive limit for tangential-fired boilers 

burning subbituminous coal. Annual NOx emission reductions from LNB with advanced OFA 

on Unit 3 and 4 are 2,723 tons and 6,142 tons, respectively. 

LNB with advanced OFA on Units 3 and 4 is cost effective, with an average cost effectiveness of 

$648 per ton of NOx removed for Unit 3 and $137 per ton for Unit 4. Combustion control using 

LNB with advanced OFA does not require non-air quality environmental mitigation for the use 

of chemical reagents (i.e., ammonia or urea) and there is a minimal energy impact.

For control of PM/PM10 emissions, the State of Wyoming requires that PacifiCorp install and 

operate new full-scale fabric filters on Units 3 and 4 to meet corresponding BART emission 

limits on a continuous basis. When considering all the factors above and beyond the benefits 

associated with regional haze which include the existing precipitator’s current condition and 

performance and end of life issues, the ability of the current electrostatic precipitator to meet an 

ESP BART rate of 0.23 lb/MMBtu on a continuous basis and the enhanced mercury removal cobenefits the baghouse provides, the Wyoming Air Quality Division has determined that the costs 

associated with the installation of a new full-scale fabric filter are reasonable. A full-scale fabric
105

filter is the most stringent PM/PM10 control technology and therefore the Division accepts it as 

BART. The Division considers the installation and operation of the BART-determined PM/PM10

controls of a new full-scale fabric filter on Unit 3 at Dave Johnston, as recently permitted in Air 

Quality Permit MD-5098, to meet the requirements of BART. 

When considering all the factors above and beyond the benefits associated with regional haze 

which include the existing venturi scrubber’s current condition and performance and end of life 

issues, the ability of the current venturi scrubber to meet a venturi scrubber BART rate of 0.21 

lb/MMBtu on a continuous basis and the enhanced mercury removal co-benefits the baghouse 

provides, the Wyoming Air Quality Division has determined that the costs associated with the 

installation of a new full-scale fabric filter are reasonable. A full-scale fabric filter is the most 

stringent PM/PM10 control technology and therefore the Division accepts it as BART. The 

Division considers the installation and operation of the BART-determined PM/PM10 controls of a 

new full-scale fabric filter on Unit 4 at Dave Johnston, as recently permitted in Air Quality 

Permit MD-5098, to meet the requirements of BART.

Visibility impacts were addressed in a comprehensive visibility modeling analysis covering three 

visibility impairing pollutants and associated control options. The cumulative 3-year averaged 

98th percentile visibility improvement from baseline, summed across all four Class I areas

(Badlands and Wind Cave national parks, and Mt. Zirkel and Rawah wilderness areas) and 

achieved with LNB with advanced OFA, dry FGD, and a new full-scale fabric filter, was 3.558 

Δdv from Unit 3 and 1.963 Δdv from Unit 4. 

The State of Wyoming considers the BART-determined permit limit to be equivalent to the

control effectiveness of a control technology. The limit is based on continuous compliance when 

the control equipment is well maintained and operated in a manner consistent with good air 

pollution control practices for minimizing emissions. 

Unit-by-unit BART determinations for NOx and PM/PM10: 

Unit Pollutant Control Type lb/MMBtu lb/hr tpy 

3 

NOx LNB/OFA 0.28 (30-day rolling) 784 (30-day rolling) 3,434 

PM/PM10 

(a) Fabric Filter 0.015 42.1 184 

4 

NOx LNB/OFA 0.15 (30-day rolling) 615 (30-day rolling) 2,694 

PM/PM10 

(a) Fabric Filter 0.015 61.5 269 

(a) Filterable portion only

LNB = low NOx burners

OFA = overfire air

III. Expeditious Installation and Operation of BART 

The State of Wyoming requires that PacifiCorp install and operate new low NOx burners with 

advanced OFA on Units 3 and 4, in accordance with the Division’s BART determination, and 

conduct the required initial performance tests to demonstrate compliance as expeditiously as 

practicable, but no later than five years after EPA approval of the state implementation plan 

revision. The State of Wyoming requires that PacifiCorp install new full-scale fabric filters on 
106

Units 3 and 4, in accordance with the Division’s BART determination, and conduct the initial 

performance tests required to demonstrate compliance as expeditiously as practicable, but no 

later than five years after EPA approval of the state implementation plan revision. 

IV. Proper Maintenance and Operation of Control Equipment 

The State of Wyoming requires that PacifiCorp follow the monitoring and recordkeeping 

requirements of Section 6.4 V. to ensure proper maintenance and operation of control equipment. 

6.5.6 PacifiCorp - Naughton Power Plant 

I. The Five-Factor Analysis

After considering (1) the costs of compliance, (2) the energy and non-air quality environmental 

impacts of compliance, (3) any pollution equipment in use or in existence at the source, (4) the 

remaining useful life of the source, and (5) the degree of improvement in visibility (all five 

statutory factors) from each proposed control technology, the Division determined BART for 

NOx and PM10 emitted from the three units subject to BART at the Naughton Power Plant. 

For control of NOx emissions, the State of Wyoming requires that PacifiCorp install and operate 

LNB with advanced OFA as BART for Units 1 and 2, and tune the existing LNB/OFA system on 

Unit 3 and install SCR. Annual NOx emission reductions from baseline for LNB with advanced 

OFA on Units 1 and 2 are 2,334 and 2,649 tons, respectively. Annual NOx emission reductions 

from baseline achieved by tuning the existing LNB/OFA and installing SCR on Unit 3 are 5,542 

tons. 

LNB with advanced OFA on Units 1 and 2 is cost effective, with an average cost effectiveness of 

$426 and $357, respectively, per ton of NOx removed for each unit over a twenty-year 

operational life. Combustion control using LNB with advanced OFA for Units 1 and 2 does not 

require non-air quality environmental mitigation for the use of chemical reagents (i.e., ammonia 

or urea) and there is a minimal energy impact. The cost effectiveness of tuning the existing LNB 

with OFA and installing SCR on Unit 3 was reasonable, with a value of $2,830 per ton of NOx

removed. 

For control of PM/PM10 emissions, the State of Wyoming requires that PacifiCorp utilize the 

existing ESPs and add FGC as BART for Units 1 and 2. The control technology is cost effective 

for each unit, with costs per ton removed of $1,721 for Unit 1 and $949 for Unit 2. No negative 

non-air environmental impacts are anticipated from the use of existing ESPs with FGC. For 

control of PM/PM10 emissions from Unit 3, the State of Wyoming requires that PacifiCorp install

and operate a new, full-scale fabric filter to meet a corresponding BART emission limit on a 

continuous basis. When considering all the factors above and beyond the benefits associated 

with regional haze which include the existing precipitator’s current condition and performance 

and end-of-life issues, the ability of the current electrostatic precipitator to meet an ESP BART 

rate of 0.04 lb/MMBtu on a continuous basis, the enhanced mercury removal co-benefits the 

baghouse provides, and the reduced ash loading on the SO2 scrubber which will enhance the 

scrubber performance, the Wyoming Air Quality Division has determined that the costs 
107

associated with the installation of a new full-scale fabric filter are reasonable. A full-scale fabric 

filter is the most stringent PM/PM10 control technology and therefore the Division accepts it as 

BART. The Division considers the installation and operation of the BART-determined PM/PM10

controls of a new full-scale fabric filter on Unit 3 to meet the statutory requirements of BART. 

Visibility impacts were addressed in a comprehensive visibility modeling analysis covering three 

visibility impairing pollutants and associated control options. The cumulative 3-year averaged 

98th percentile visibility improvement from the baseline across Bridger WA and Fitzpatrick WA 

achieved with LNB with advanced OFA, wet FGD, and FGC for enhanced ESP control was 

1.716 Δdv from Unit 1 and 1.934 Δdv from Unit 2. While the visibility improvement 

attributable to the installation of FGC on existing ESPs can’t be directly determined from the 

visibility modeling, the Division does not anticipate the PM contribution to be significant when 

compared to the NOx and SO2 contributions. For Unit 3, the cumulative 3-year averaged 98th

percentile visibility improvement from the baseline summed across both Class I areas achieved 

by tuning the existing LNB with OFA, wet FGD and installing a new full-scale fabric filter, was 

0.826 Δdv. The installation of SCR on Unit 3 produces an additional 1.023 Δdv in cumulative, 

3-year averaged 98th percentile modeled visibility improvement across the two Class I areas. 

The State of Wyoming considers the BART-determined permit limit to be equivalent to the

control effectiveness of a control technology. The limit is based on continuous compliance when 

the control equipment is well maintained and operated in a manner consistent with good air 

pollution control practices for minimizing emissions. 

Unit-by-unit BART determinations for NOx and PM/PM10: 

Units Pollutant Control Type lb/MMBtu lb/hr tpy 

1 

NOx LNB/OFA 0.26 (30-day rolling) 481 (30-day rolling) 2,107 

PM/PM10

(a) ESP + FGC 0.040 74 324 

2 

NOx LNB/OFA 0.26 (30-day rolling) 624 (30-day rolling) 2,733 

PM/PM10

(a) ESP + FGC 0.040 96 421 

3 

NOx Tune LNB/OFA + SCR 0.07 (30-day rolling) 259 (30-day rolling) 1,134 

PM/PM10

(a) Fabric Filter 0.015 56 243 

(a) Filterable portion only

ESP = electrostatic precipitator

FGC = flue gas conditioning

LNB = low NOx burners

OFA = overfire air

III. Expeditious Installation and Operation of BART 

The State of Wyoming requires that PacifiCorp install and operate new low NOx burners with 

advanced OFA and install flue gas conditioning on the existing ESPs on Units 1 and 2, in 

accordance with the Division’s BART determination, and conduct the required performance tests 

to demonstrate compliance as expeditiously as practicable, but no later than five years after EPA 

approval of the state implementation plan revision. 
108

The State of Wyoming requires that PacifiCorp shall tune the existing low NOx burners with 

OFA and install selective catalytic reduction and a full-scale fabric filter on Unit 3, in accordance 

with the Division’s BART determination to demonstrate compliance as expeditiously as 

practicable, but no later than five years after EPA approval of the state implementation plan 

revision. 

 

IV. Proper Maintenance and Operation of Control Equipment 

The State of Wyoming requires that PacifiCorp follow the monitoring and recordkeeping 

requirements of Section 6.4 V. to ensure proper maintenance and operation of control equipment. 

6.5.7 PacifiCorp - Wyodak Power Plant 

I. The Five-Factor Analysis

After considering (1) the costs of compliance, (2) the energy and non-air quality environmental 

impacts of compliance, (3) any pollution equipment in use or in existence at the source, (4) the 

remaining useful life of the source, and (5) the degree of improvement in visibility (all five 

statutory factors) from each proposed control technology, the Division determined BART for 

NOx and PM10 emitted from the single unit subject to BART at the Wyodak Power Plant. 

For control of NOx emissions, the State of Wyoming requires that PacifiCorp install and operate 

LNB with advanced OFA as BART for Unit 1. Annual NOx emission reductions from baseline 

with LNB with advanced OFA on Unit 1 are 1,483 tons. LNB with advanced OFA on Unit 1 is

cost effective, with an average cost effectiveness of $881 per ton of NOx removed over a twentyyear operational life. Combustion control using LNB with advanced OFA does not require nonair quality environmental mitigation for the use of chemical reagents (i.e., ammonia or urea) and 

there is a minimal energy impact. 

For control of PM/PM10 emissions from Unit 1, the State of Wyoming requires that PacifiCorp 

install and operate a new, full-scale fabric filter to meet a corresponding BART emission limit on 

a continuous basis. When considering all the factors above and beyond the benefits associated 

with regional haze which include the existing precipitator’s current condition and performance 

and end of life issues, the ability of the current electrostatic precipitator to meet an ESP BART 

rate of 0.10 lb/MMBtu on a continuous basis, and the enhanced mercury removal co-benefits the 

baghouse provides, the Wyoming Air Quality Division has determined that the costs associated 

with the installation of a new full-scale fabric filter are reasonable. A full-scale fabric filter is the 

most stringent PM/PM10 control technology and therefore the Division accepts it as BART. The 

Division considers the installation and operation of the BART-determined PM/PM10 controls of a 

new full-scale fabric filter at Wyodak, as recently permitted under Air Quality Permit MD-7487, 

to meet the requirements of BART.

Visibility impacts were addressed in a comprehensive visibility modeling analysis covering three 

visibility impairing pollutants and associated control options. The cumulative 3-year averaged 

98th percentile visibility improvement from the baseline summed across both Class I areas

(Badlands and Wind Cave national parks) achieved with LNB with advanced OFA, upgrading 

the dry FGD, and a new full-scale fabric filter was 0.996 Δdv. 
109

The State of Wyoming considers the BART-determined permit limit to be equivalent to the

control effectiveness of a control technology. The limit is based on continuous compliance when 

the control equipment is well maintained and operated in a manner consistent with good air 

pollution control practices for minimizing emissions. 

Unit-by-unit BART determinations for NOx and PM/PM10: 

Unit Pollutant Control Type lb/MMBtu lb/hr tpy 

1 

NOx LNB/OFA 0.23 (30-day rolling) 1,081.0 (30-day rolling) 4,735 

PM/PM10 

(a) Fabric Filter 0.015 71.0 309 

(a) Filterable portion only

LNB = low NOx burners

OFA = overfire air

III. Expeditious Installation and Operation of BART 

The State of Wyoming requires that PacifiCorp install new low NOx burners with advanced OFA 

and a new full-scale fabric filter on Unit 1, in accordance with the Division’s BART 

determination, and conduct the initial performance tests to demonstrate compliance as 

expeditiously as practicable, but no later than five years after EPA approval of the state 

implementation plan revision. 

IV. Proper Maintenance and Operation of Control Equipment 

The State of Wyoming requires that PacifiCorp follow the monitoring and recordkeeping 

requirements of Section 6.4 V. to ensure proper maintenance and operation of control equipment. 

6.5.8 Basin Electric Power Cooperative - Laramie River Station

The Air Quality Division issued a BART permit for Basin Electric Power Cooperative - 

Laramie River Station on December 31, 2009 under Permit No. MD-6047. A summary of the 

Division’s five-factor analysis performed to support the BART permit issued on December 31, 

2009 is included below. The detailed five-factor analysis is included in Attachment A of this 

SIP.

I. The Five-Factor Analysis

After considering (1) the costs of compliance, (2) the energy and non-air quality environmental 

impacts of compliance, (3) any pollution equipment in use or in existence at the source, (4) the 

remaining useful life of the source, and (5) the degree of improvement in visibility (all five 

statutory factors) from each proposed control technology, the Division determined BART for 

NOx and PM10 emitted from the three units at the Laramie River Station.

For control of NOx emissions, the State of Wyoming requires that Basin Electric install new LNB 

with OFA as BART for Units 1 through 3. Annual NOx emission reductions from new LNB 
110

with OFA on Units 1, 2, and 3 are 1,862-1,910 tons per unit for a total annual reduction of 5,645 

tons. 

LNB with separated OFA on Units 1 through 3 is cost effective, with an average cost 

effectiveness of $2,036-$2,088 per ton of NOx removed for each unit over a twenty-year 

operational life. Combustion control using LNB with OFA does not require non-air quality 

environmental mitigation for the use of chemical reagents (i.e., ammonia or urea) and there is a 

minimal energy impact. 

For control of PM/PM10 emissions, the State of Wyoming requires that Basin Electric utilize the 

existing ESPs as BART for Units 1 through 3. The cost of compliance for the sole technically 

feasible control option, a retrofit fabric filter on the Unit 3 ESP, is not reasonable over a twentyyear operational life. No negative non-air environmental impacts are anticipated from use of the 

existing ESPs. 

Visibility impacts were addressed in a comprehensive visibility modeling analysis covering three 

visibility impairing pollutants and associated control options. The cumulative 3-year averaged 

visibility improvement from the baseline across Wind Cave NP and Badlands NP achieved with 

new LNB with OFA at the 30-day limit of 0.23 lb/MMBtu (based on the 98th percentile modeled 

results) was 0.14 Δdv from each of the three units. The expected visibility improvement over the 

course of a full annual period would be even greater due to the annual BART limit that is based 

on 0.19 lb/MMBtu. 

 

The State of Wyoming considers the BART-determined permit limit to be equivalent to the

control effectiveness of a control technology. The limit is based on continuous compliance when 

the control equipment is well maintained and operated in a manner consistent with good air 

pollution control practices for minimizing emissions. 

Unit-by-unit BART determinations for NOx and PM/PM10: 

Units Pollutant Control Type lb/MMBtu lb/hr tpy 

1 

NOx LNB/OFA 0.23 (30-day rolling) 1,348 (30-day rolling) 5,343 (12-month 

rolling)

PM/PM10

(a) ESP 0.030 193 844 

2 

NOx LNB/OFA 0.23 (30-day rolling) 1,348 (30-day rolling) 5,343 (12-month 

rolling)

PM/PM10 

(a) ESP 0.030 193 844 

3 

NOx LNB/OFA 0.23 (30-day rolling) 1,386 (30-day rolling) 5,493 (12-month 

rolling)

PM/PM10

(a) ESP 0.030 198 867 

(a) Filterable portion only

ESP = electrostatic precipitator

LNB = low NOx burners

OFA = overfire air

The performance/efficiency-based, 30-day rolling average emission rate of 0.23 lb/MMBtu is set 

to allow for continuous compliance with proper operation of the control equipment, while taking 

into account the normal operational variability that is typical for a boiler. The 30-day limits that 
111

are expressed in terms of mass emissions (lb/hr) are based on 0.21 lb/MMBtu. Because reduced 

steam loads on a boiler can result in periods of increased emissions in terms of lb/MMBtu but 

lower emissions in terms of lb/hr, the Division has chosen to set the dual 30-day limits, one set at 

0.23 lb/MMBtu and one expressed in lb/hr based on 0.21 lb/MMBtu. For the 12-month rolling 

emission limits, the Division considered the ability of the source to maintain a lower emission 

rate over a longer time period and set the long-term limit (expressed in tpy) based on 0.19 

lb/MMBtu. 

III. Expeditious Installation and Operation of BART 

The State of Wyoming requires that Basin Electric install new low NOx burners with separated 

OFA on Units 1 through 3, in accordance with the Division’s BART determination, and conduct 

the required initial performance tests to demonstrate compliance as expeditiously as practicable, 

but no later than five years after EPA approval of the state implementation plan revision. 

The State of Wyoming requires that Basin Electric continue the use of the existing ESPs on Units 

1 through 3 to achieve the BART emissions limits. The PM/PM10 compliance deadline was 

March 31, 2010. 

IV. Proper Maintenance and Operation of Control Equipment 

The State of Wyoming requires that Basin Electric follow the monitoring and recordkeeping 

requirements of Section 6.4 V. to ensure proper maintenance and operation of control equipment. 

Subsequent NOx BART Determinations 

On March 8, 2010, Basin Electric Power Cooperative appealed the BART permit for the 

Laramie River Station before the Wyoming Environmental Quality Council (EQC). The 

Department of Environmental Quality entered into a settlement agreement on November 16, 

2010 with Basin Electric Power Cooperative (Docket No. 10-2802). On December 8, 2010, the 

Division held a State Implementation Plan (SIP) Hearing on Regional Haze. The SIP hearing 

was held in Cheyenne, Wyoming at the Laramie County Library, 2200 Pioneer Avenue. At 

that time, the Division collected public comment on the Regional Haze SIP revisions.

After carefully considering all comments on revisions to the State Implementation Plan to 

address Regional Haze, the Division has determined that the following table, taken from the 

Settlement Agreement Filed November 16, 2010 before the Wyoming EQC and incorporated 

into the EQC Order approving the Settlement, shall establish the BART limits for three units 

at Laramie River Station with respect to NOx and NOx only, and that these BART limits shall 

replace the BART limits for NOx determined by the Division in Permit MD-6047 issued on 

December 31, 2009. The Division has remodeled the emission limits established through this 

Settlement to determine the resulting visibility impacts. This impact analysis is included in 

Attachment A.
112

Effective upon completion of the initial performance tests to verify the emission levels below, 

emissions from Laramie River Station Units 1 through 3 shall not exceed the levels below. 

The NOx limits shall apply during all operating periods.

Pollutant lb/MMBtu lb/hr tpy

NOx 0.21 (30-day rolling) Unit 1: 1,220

Unit 2: 1,220 

Unit 3: 1,254 

(all 30-day rolling)

Unit 1: 4,780

Unit 2: 4,780 

Unit 3: 4,914 

(all 12-month rolling)

Overall NOx Reductions in Wyoming 

In the State of Wyoming, significant additional NOx reductions will be made at the completion of 

the BART process. The overall cumulative NOx reductions from Wyoming BART sources over 

time are demonstrated in the figure below. If regional funding becomes available, future 

regional modeling will demonstrate the additional progress towards 2018 visibility goals. 

Figure 6.5.8-1. Additional Cumulative NOx Reductions From Wyoming BART Sources
113

CHAPTER 7 

REASONABLE PROGRESS GOALS

7.1 Overview

The fundamental purpose of the Regional Haze Rule (RHR) is to restore visibility in all 

mandatory Class I areas across the United States to natural conditions by the year 2064. As 

required by the RHR, each state must submit a State Implementation Plan (SIP) that addresses 

visibility reductions in Class I areas for the initial planning period of 2005-2018, with successive 

revisions occurring every ten years after 2018. In order to demonstrate incremental visibility 

improvement during the first planning period, the State of Wyoming was required to establish 

reasonable progress goals (RPGs) for the seven Class I areas within the state. 

Reasonable progress goals listed in Section 7.5 of this chapter are used to gauge the progress that 

the State of Wyoming can reasonably make towards improving visibility to natural conditions in 

Class I areas within the state. Each Class I area RPG consists of two visibility values, expressed 

as deciviews (dv), that represent the most impaired visibility days (i.e., the average of the 20% 

most impaired days over an entire year) and the least impaired visibility days (i.e., the average of 

the 20% least impaired days over an entire year).

While the reasonable progress goals are not enforceable, the control measures adopted by the 

State of Wyoming are enforceable. To determine if reasonable progress is being made in 

improving visibility, the State will need to collect and analyze air quality data and update the 5-

year visibility averages for the 20% worst visibility days and the 20% best visibility days and 

compare the 5-year average with the baseline conditions (after 2018, the 5-year average will be 

compared to the impairment levels reported in the previous SIP revision). If the control 

measures set by the State do not result in a reduction in visibility impairment equal to or greater 

than the RPG for 2018, then the State of Wyoming can either revise its control strategies to meet 

the RPG or revise the RPG for the next planning period. 

 

RPGs are non-enforceable, interim goals, expressed in deciviews, which represent interim 

visibility improvement in an effort to eventually achieve natural visibility conditions in Class I 

areas. When RPGs are established, they must provide for visibility improvement for the 20% 

worst visibility days and ensure that there is not a reduction in visibility for the least impaired 

days, calculated as the 20% best visibility days, through 2018. For states with multiple Class I 

areas, RPGs can be established separately for each one. The established goals must represent 

greater visibility improvement than what would result from the other requirements of the Clean 

Air Act (CAA). 

States must revisit their reasonable progress goals in 2018, as discussed in Chapter 10, by 

evaluating the progress towards natural conditions and the effectiveness of the long-term strategy 

for achieving the goals. If progress towards natural visibility conditions is unsatisfactory, the 

reasonable progress goals can be revised. 
114

7.2 Process for Establishing Reasonable Progress Goals 

Several steps for establishing reasonable progress goals were outlined in the RHR and are 

discussed in the following subsections. 

• Calculate/Estimate Baseline and Natural Visibility Conditions 

Baseline visibility conditions were determined by the Western Regional Air Partnership (WRAP) 

Technical Support System (TSS) using the Interagency Monitoring of Protected Visual 

Environments (IMPROVE) algorithm. The IMPROVE algorithm followed the established 

guidelines presented in the RHR. To determine baseline visibility conditions, the average degree 

of visibility (expressed as dv) for the 20% least impaired days and the 20% worst impaired days 

was calculated, using IMPROVE air quality monitoring data, for each calendar year from 2000 

to 2004. The IMPROVE monitoring program collects speciated PM2.5, and PM2.5 and PM10

mass. IMPROVE is a nationwide network which began in 1988 and expanded significantly in 

2000 in response to the EPA’s Regional Haze Rule (RHR). The Regional Haze Rule specifically 

requires data from this program to be used by states and tribes to track progress in reducing haze. 

The annual values were then averaged over five years to determine the baseline visibility 

condition values. Baseline visibility is discussed in detail in Chapter 2.

Natural conditions are an estimate of the amount of visibility impairment that would occur if no 

human-caused visibility impairment existed. Natural conditions were determined by the WRAP 

through the Natural Haze Levels II Committee for the 20% worst visibility days and the 20% 

best visibility days using available monitoring data and the IMPROVE algorithm. The Natural 

Haze Levels II Committee was established in 2006 to review and refine the default approach. 

The committee included representatives from NOAA, NPS, Cooperative Institute for Research in 

the Atmosphere (CIRA), Regional Planning Organizations (RPOs) and industry representatives, 

and other participants. The final report of the committee can be found at: 

http://wrapair.org/forums/aoh/meetings/060726den/NaturalHazeLevelsIIReport.pdf. Additional 

information about the baseline and natural visibility impairment calculations can be found in 

Chapter 13. 

• Determine the Uniform Rate of Progress (URP)

The URP (also known as the glide slope), which was determined by the State of Wyoming for all 

mandatory Class I areas within the state, is the rate of visibility change necessary to achieve 

natural visibility conditions by the year 2064. The URP represents the slope between baseline 

visibility conditions in 2004 and natural visibility conditions in 2064. Using interpolation, the 

improvement necessary by 2018 to achieve natural visibility conditions in 2064 can be calculated

as shown in Table 7.2-1. The URP is discussed in greater detail in Chapters 3 and 5. 
115

Table 7.2-1. 20% Best and Worst Days Baseline, Natural Conditions, and Uniform Rate of 

 Progress Goal for Wyoming Class I Areas 

IMPROVE

Monitor

Name

Wyoming Class I Areas

20% Worst Days 20% Best Days

2000-04 

Baseline

(dv)

2018

URP 

Goal 

(dv)

2018 

Reduction

Needed

(dv)

2064 

Natural 

Conditions 

(dv)

Future Date 

for Reaching 

Natural 

Conditions at 

Current Rate

2000-04 

Baseline

(dv)

2064 

Natural 

Conditions 

(dv)

YELL2

Yellowstone National Park

Grand Teton National Park

Teton Wilderness

11.8 10.5 1.3 6.4 2130 2.6 0.4

NOAB1 North Absaroka Wilderness

Washakie Wilderness 11.5 10.4 1.1 6.8 2136 2.0 0.6

BRID1 Bridger Wilderness

Fitzpatrick Wilderness 11.1 10.0 1.1 6.5 2165 2.1 0.3

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

 

• Four Factor Analysis

In an effort to reduce visibility impairing air pollutants, emission control measures had to be 

evaluated. The four factor analysis process was established in the RHR and is discussed in detail 

in Section 7.3 of this chapter. Each emission control strategy, as required by the four factor 

analysis guidelines, was evaluated based on 1) the cost of compliance, 2) time necessary for 

compliance, 3) the energy and non-air quality environmental impacts of compliance, and 4) the 

remaining useful life of any existing source subject to such emission controls. 

• Consultation With Other States

According to the RHR, the State of Wyoming must consult with other states that may cause or 

contribute to visibility impairment in Wyoming Class I areas. For the State of Wyoming, 

consultations with other states contributing to visibility impairment in Class I areas were 

conducted through the WRAP. Additional information on the state consultations can be found in 

Chapter 11. 

• Determination of Reasonable Progress Goals 

Reasonable progress goals, when established, demonstrate the amount of visibility improvement 

the State of Wyoming believes to be feasible, based on the four factor analysis and Clean Air Act 

(CAA) requirements, during the first planning period. The reasonable progress goal may be the 

same, less stringent, or more stringent than the visibility improvement based on the URP. The 

reasonable progress goals, and the logic used to determine the goals, are discussed in Sections 

7.5 and 7.6 of this chapter. 

7.3 Four Factor Analysis Performed for Wyoming Sources

The four factor analysis, which is presented in the RHR, is a method for evaluating potential 

control strategies for facilities that are not eligible for Best Available Retrofit Technology 

(BART) or better-than-BART programs. The analysis considers 1) the cost of compliance, 2) the 

time necessary for compliance, 3) environmental impacts of compliance, and 4) the remaining 

useful life of the facility. 
116

The WRAP hired EC/R Incorporated (EC/R), headquartered in Chapel Hill, North Carolina, to 

complete the four factor analysis. Control measures for NOx and direct particulate matter 

emissions were evaluated for selected sources in Wyoming. A four factor analysis is not 

required for SO2 since the State of Wyoming has addressed visibility impairment associated with 

this pollutant under the 309 SIP previously submitted to EPA. 

7.3.1 Detailed Description of the Four Factors 

• Cost of Compliance 

Both control costs and net annual costs were analyzed for all control measures identified by 

EC/R. Control costs cover direct and indirect capital costs. Examples of direct capital expenses 

includes the costs associated with purchased equipment, construction, installation, 

instrumentation and process controls, ductwork and piping, electrical components, and structural 

and foundation components. Indirect capital expenses include costs such as engineering and 

design, contractor fees, startup and performance testing, contingency costs, and process 

modifications.

Net annual costs include the expenses associated with the typical operation of the control 

equipment over a year. Annual costs include items such as the utility expenses, labor, waste 

disposal expenses, and amortized costs of the capital investment. All cost estimates calculated 

by EC/R were updated to 2007 dollars using the Marshall and Swift Equipment Cost Index or the 

Chemical Engineering Plant Cost Index, which are both published in the journal Chemical 

Engineering. 

• Time Necessary for Compliance

The time necessary for compliance includes the time needed for the State of Wyoming to 

develop and implement regulations for emissions controls, as well as the time the sources require 

to procure the capital to purchase the emission control equipment, design and fabricate the 

equipment, and to install the emission controls. When a retrofit control device is required, the 

time necessary for compliance includes the time for capital procurement, device design, 

fabrication, and installation. 

• Energy and Other Non-Air Quality Environmental Impacts

Emission control devices often require some form of energy input to operate. To determine the 

energy requirements for a particular control device, the electricity needs, steam requirements, 

increased fuel requirements, and any additional energy inputs required were quantified. Only the 

direct energy requirements were considered; indirect energy needs, such as the amount of energy 

required to produce the fuel for the control device, were not analyzed. In addition, any impacts 

the control technologies had on other source processes, such as boiler efficiency, were not 

evaluated. 
117

While the control devices reduce air pollution, they often produce waste. Environmental impacts 

of each control technology were analyzed by EC/R and included the waste generated, the 

wastewater generated, additional CO2 produced, reduced acid deposition, and reduced nitrogen 

deposition. If available, the benefits from PM2.5 and ozone reductions were also evaluated. 

• Remaining Equipment Life at Source 

The remaining equipment life of the source will impact the cost of emission control technologies 

if the expected life of the source is less than the lifetime of the pollution control device being 

considered. Therefore, if the remaining equipment life is less than the lifetime of the pollution 

control device, the capital cost of the pollution control device is amortized for the remaining life 

of the emission source. To determine the annual cost of the emission control device if the 

expected life of the source is less than the expected life on the control device, the following 

equation can be used: 

where:

 A1 = the annual cost of control for the shorter equipment life ($) 

 A0 = the original annual cost estimate ($)

C = the capital cost of installing the control equipment ($)

r = the interest rate (0.07)

m = the expected remaining life of the emission source (years)

 n = the projected lifetime of the pollution control equipment 

7.3.2 Source Selection Process for Four Factor Analysis 

To select the sources that would undergo the required four factor analysis, emission data for 

sources in Wyoming had to first be collected. This was accomplished using the WRAP 

Emissions Data Management System (EDMS), which contains inventories from stationary 

sources, fires, area sources, on-road mobile sources, off-road mobile sources, windblown dust, 

and biogenic sources across the state. After evaluating the emissions, it was determined that the 

primary emissions from anthropogenic sources, which are sources the State of Wyoming can 

regulate, were NOx and SO2 based on Tables 4.2-1 and 4.3-1, and Figures 5.2.1-1 through 5.2.1-

3 and 5.2.3-1 through 5.2.3-3 found in Chapters 4 and 5. Since sources of SO2 were addressed in 

great detail in the previous 309 submittal, this screening process focuses on NOx sources. 

A basic screening technique, referred to as the Quantity over Distance or “Q over D” analysis, 

was implemented by the State of Wyoming in order to select the sources to undergo the four 

factor analysis. There is no requirement to use this technique, but it has been employed by EPA 

and other states to roughly determine which sources had the largest contributions of visibility 

impairing pollutants in Class I areas in Wyoming and surrounding states. It is a basic, intuitive 

tool that allows the State to evaluate emissions from sources of concern. The sources of concern 

in this first SIP were the large sources that were similar in magnitude to the sources covered 

under BART, but were not covered by the timeframe requirements of BART. 
118

The screening technique included sources when the following was met: 

 

where Q represents the maximum emission rate, in tons per year, of the source and D is the 

distance in kilometers to the nearest Class I area. A spreadsheet showing all of the sources with

a Q/D greater than 10 can be found in Chapter 7 of the Wyoming TSD. Three emission units 

were identified in the state having and thereby selected to undergo the four factor 

analysis.

7.3.3 PacifiCorp Dave Johnston Electric Generating Station 

Two units, BW41 and BW42, at the Dave Johnston Electric Generating Station were selected for 

the four factor analysis in Wyoming. Both units are sub-bituminous coal-fired boilers capable of 

producing up to 114 megawatts (MW). Emissions are currently controlled with a cold-side 

electrostatic precipitator (ESP). 

Four possible emission control devices were identified and analyzed using the four factor 

analysis process for the boilers: low NOx burners (LNB), low NOx burners with overfire air 

(LNB w/OFA), selective non-catalytic reduction (SNCR), and selective catalytic reduction 

(SCR). LNB technology reduces the amount of NOx produced by reducing the flame 

temperature. The flame temperature is reduced by controlling the fuel and air mixing, which 

creates a larger, branched flame. LNB w/OFA reduces NOx emissions by separating the 

combustion air into primary and secondary flows. When the combustion air is separated, a more 

complete burn occurs and forms N2 rather than NOx. With SNCR, an aqueous reagent, typically 

either ammonia or urea, is injected into the hot flue gas. The reagent reacts with the NOx in the 

gas to form N2 and water vapor. Similar to the SNCR technology, SCR technology uses 

ammonia to reduce NOx to N2 and H2O. However, with SCR the NOx in the flue gas reacts with 

the ammonia within a catalyst bed.

• Cost 

The estimated capital costs, annual costs, and the cost effectiveness for the possible emission 

control devices at the Dave Johnston Electric Generating Station are shown in Table 7.3.3-1. 

The capital costs, which are expressed in terms of cost per MW size, were estimated based on a 

cost estimate document produced by the EPA.4

 The capital costs for the Dave Johnston boilers 

had to be extrapolated from the cost estimate data provided by the EPA reference due to their 

large size. To determine the annual costs for the control devices, the capital costs were 

amortized over 20 years at an interest rate of 7% and then multiplied by a factor to account for 

operation and maintenance (O&M) costs. While SCR is expected to be far more efficient in 

controlling NOx emissions than LNB or LNB w/OFA, the estimated capital and annual costs are 

far higher than the costs associated with LNB or LNB w/OFA. As shown in Table 7.3.3-1, NOx

 

4 EPA (2002), EPA Air Pollution Control Cost Manual, 6th ed., EPA/452/B-02-001, U.S. EPA, Office of Air 

Quality Planning and Standards, RTP, NC, Section 5 - SO2 and Acid Gas Controls, pp 1-30 through 1-42, 

http://www.epa.gov/ttncatc1/products.html#cccinfo. 
119

reductions using LNB or LNB w/OFA technology are far more cost effective than the SNCR and 

SCR technologies. 

Table 7.3.3-1. Estimated Costs of Potential Emission Control Devices for Two Boilers at 

 the Dave Johnston Electric Generation Stationx

Cost Estimates

Unit ID Control 

Technology

Estimated 

Control 

Efficiency (%)

Estimated

Capital Cost 

($)

Annual Cost ($/year) Cost Effectiveness ($/ton)

BW41 LNB 51 4,030,000 631,000 528

LNB w/OFA 65 5,760,000 962,000 632

SNCR 40 4,160,000 2,490,000 2,659

SCR 80 11,500,000 3,390,000 1,810

BW42 LNB 51 4,030,000 631,000 538

LNB w/OFA 65 5,760,000 962,000 644

SNCR 40 4,160,000 2,490,000 2,709

SCR 80 11,500,000 3,390,000 1,844 x

All values listed in Table 7.3.3-1 were obtained from the EC/R Incorporated report “Supplementary Information for 

Four-Factor Analyses for Selected Individual Facilities in Wyoming” and is included in Chapter 7 of the Wyoming 

TSD.

• Time Necessary for Compliance

EC/R estimated that it would take nearly five and a half years for NOx reduction strategies to 

become effective. It was determined that roughly two years would be necessary for the State of 

Wyoming to develop the necessary regulations to implement the selected control measures. 

EC/R estimated that it would take up to a year for the source to secure the capital necessary to 

purchase emission control devices. Based on estimates calculated by the Institute of Clean Air 

Companies (ICAC), approximately 18 months would be required for a company to design, 

fabricate, and install SCR or SNCR technology. Since there are two boilers being evaluated at 

Dave Johnston, an additional year may be required for staging the installation process. 

• Energy and Non-Air Quality Environmental Impacts

The energy required to operate the emission control devices, including electricity and steam, and 

the waste produced by the emission control devices, such as solid waste and wastewater, are 

shown in Table 7.3.3-2. As illustrated by the values in Table 7.3.3-2, none of the four 

technologies are expected to produce solid waste or wastewater. However, it should be noted 

that the SCR technology would periodically produce solid waste when the catalyst would need to 

be changed. While LNB and LNB w/OFA do not require steam, both SNCR and SCR require 

steam to operate. None of the technologies are expected to increase fuel consumption, though 

LNB and LNB w/OFA may reduce the fuel consumption due to optimized fuel combustion. In 

addition, LNB and LNB w/OFA technologies need roughly 1/6th the electricity required by 

SNCR and 1/150th the electricity required by SCR. 
120

Table 7.3.3-2. Estimated Energy and Non-Air Environmental Impacts of Potential 

 Emission Control Devices for Two Boilers at the Dave Johnston Electric

 Generation Stationx

Energy and Non-Air Pollution Impacts

Unit ID Control 

Technology

Estimated 

Control 

Efficiency (%)

Electricity 

Requirements 

(kW)

Steam 

Requirements 

(lb/hr)

Solid Waste 

Generated (ton/hr)

Wastewater Produced 

(gal/min)

BW41 LNB 51 5.4 N/A N/A N/A

LNB w/OFA 65 5.4 N/A N/A N/A

SNCR 40 31 439 N/A N/A

SCR 80 825 527 N/A N/A

BW42 LNB 51 5.4 N/A N/A N/A

LNB w/OFA 65 5.4 N/A N/A N/A

SNCR 40 31 431 N/A N/A

SCR 80 825 517 N/A N/A x

All values listed in Table 7.3.3-2 were obtained from the EC/R Incorporated report “Supplementary Information for 

Four-Factor Analyses for Selected Individual Facilities in Wyoming” and is included in Chapter 7 of the Wyoming 

TSD.

• Remaining Life of the Boilers

The remaining life of the boilers at the Dave Johnston facility is not expected to have an impact 

on the cost of the control technologies. 

• Dave Johnston Boilers BW41 and BW42 Four Factor Analysis Conclusion 

As discussed previously, the LNB and LNB w/OFA emission control technologies have a 

relatively low cost effectiveness value when compared with the SCR and SNCR technologies. 

While the LNB and LNB w/OFA estimated control efficiencies are between fifteen and twentynine percent lower than the SCR technology, the electricity requirements are far lower for LNB 

and LNB w/OFA and neither requires steam. In addition SCR will produce solid waste every 

time the catalyst must be replaced. Therefore, based on the relatively low cost effectiveness, the 

reasonable control efficiency, possible reduction in fuel usage, low electricity requirements, and 

the fact that solid waste and wastewater will not be produced, the LNB or LNB w/OFA seem to 

be the most reasonable choice for the Dave Johnston Electric Generating Station boilers BW41 

and BW42 based on the four factor analysis. The implementation of new control technologies on 

the two boilers are discussed in further detail in Chapter 8 (Section 8.3.4), Long-Term Strategy. 

 

7.3.4 Mountain Cement Company, Laramie Plant 

At the Mountain Cement Company, Laramie Plant, only one unit was selected for the four factor 

analysis. The selected source, Cement Kiln #2, is a long dry kiln that can produce up to 1,500 

tons of clinker per day. 

Several options are available for the control of NOx emissions and include both combustion and 

NOx removal controls. Combustion control options include direct-fired low NOx burners (LNB), 

indirect-fired LNB, and the CemStar process. NOx removal control options include biosolid 

injection, LoTOx

TM, selective catalytic reduction (SCR), selective non-catalytic reduction 

(SNCR), and NOxOUT. Low NOx burners, whether installed on direct or indirect-fired kilns, 

reduce the flame turbulence, delay the fuel/air mixing, and establish fuel-rich zones for initial 
121

combustion. These three factors contribute to a reduction in thermal NOx formation. The 

CemStar process introduces a small amount of steel slag to the kiln feed, which helps reduce the 

kiln operating temperature. 

Biosolid injection uses wastewater treatment plant solids to reduce the kiln temperature required 

to produce clinker. The LoTOx system (licensed by the BOC group), which injects ozone into 

the kiln, oxidizes NOx and the resulting higher oxides of nitrogen are then removed by a wet 

scrubber. SCR technology uses a catalyst such as titanium dioxide or vanadium pentoxide to 

convert NOx to N2 and H2O. SNCR, while similar to SCR, uses ammonia or urea to reduce NOx

formation, but does not require a catalyst. NOxOUT is similar to SNCR and uses urea to convert 

NOx to nitrate and oxygen, but also has a proprietary additive that allows for a wider temperature 

range than the typical SNCR system. 

• Cost 

The estimated capital costs, annual costs, and the cost effectiveness for the possible emission 

control devices compiled by EC/R for the Mountain Cement Company, Laramie Plant are shown 

in Table 7.3.4-1. Two options, SCR and LoTOx

TM have high control efficiencies that are 

predicted to be over 80%. However, no cost data was available for the LoTOx

TM system, making 

it impossible to evaluate its viability at the Laramie facility. SCR, while an effective control 

technology, has a cost effectiveness value that makes it cost prohibitive. Of the more cost 

effective options, SNCR using either urea or ammonia appears to be the most reasonable. SNCR 

provides a control efficiency similar to many of the other control technologies, but with a far 

better cost effectiveness ratio. 

Table 7.3.4-1. Estimated Costs of Potential Emission Control Devices for One Cement

 Kiln at the Mountain Cement Company, Laramie Plant.x

Cost Estimates

Unit ID Control Technology

Estimated 

Control 

Efficiency (%)

Pollutant 

Controlled

Estimated

Capital Cost 

($)

Annual Cost 

($/year) Cost Effectiveness ($/ton)

Kiln #2

LNB (indirect) 30-40 826,000 205,000 6,568-4,910

LNB (direct) 40 2,460,000 449,000 13,853

Biosolid Injection 50 474,000 -127,000 1,324

NOxOUT 35 NOx 960,000 507,000 8,023

CemSTAR 20-60 Unknown Unknown Unknown

LoTOx

TM 80-90 Unknown Unknown Unknown

SCR 80 27,042,000 7,553,000 82,535

SNCR (urea) 35 Unknown Unknown 1,223

SNCR (ammonia) 35 Unknown Unknown 1,223

Fabric Filter 99 PM105,261,000 4,451,000 262,489

Dry ESP 95-98 10,926,000 6,475,000 483,356 - 470,292

Fabric Filter 99 PM2.55,261,000 4,451,000 647,472

Dry ESP 95-98 10,926,000 6,475,000 1,242,915 – 1,160,054 x

All values listed in Table 7.3.4-1 were obtained from the EC/R Incorporated report “Supplementary Information for 

Four-Factor Analyses for Selected Individual Facilities in Wyoming” and is included in Chapter 7 of the Wyoming 

TSD. 

• Time Necessary for Compliance

EC/R estimated that it could potentially take seven years to achieve emission reductions at the 

Laramie facility. This estimate includes the two years that will be necessary for the State of 
122

Wyoming to implement new regulations and the 1 year Mountain Cement will likely need to 

obtain the necessary capital for the purchase of new emission control technology. However, the 

total time necessary varies based on the control technology selected. For example, it is predicted 

that one and a half years will be required to design, fabricate, and install SCR or SNCR 

technology, while over two and a half years will be required to design, fabricate, and install 

LoTOx

TM technology. 

• Energy and Non-Air Quality Environmental Impacts

Table 7.3.4-2 details the energy requirements and waste produced by the potential emission 

control devices. Energy requirements include direct electricity and steam requirements, but do 

not include the energy required to produce the steam and electricity. None of the NOx control 

technologies require additional fuel and some are even predicted to increase fuel efficiency. The 

options that are expected to increase fuel efficiency are indirect and direct LNB, biosolid 

injection, and CemSTAR. However, there is no data indicating the expected fuel efficiency 

increase. Without adequate data, it is not possible to determine if the increase in fuel efficiency 

is substantial and if there is any advantage to selecting an option that increases fuel efficiency 

over an option that does not increase fuel efficiency. 

Several of the NOx control technologies are expected to require electricity and include both 

direct and indirect LNB, LoTOx

TM, and SNCR using urea or ammonia. Many of the technologies 

did not have sufficient data to quantify the energy requirements. This made it difficult to 

adequately evaluate the control options based on electricity requirements. However, some of the 

NOx control technologies are not predicted to have electricity requirements, which could make 

those options potentially more attractive. Those options include SCR, CemSTAR, NOxOUT, 

and biosolid injection. None of the NOx control technologies are expected to require steam.

Only a few of the NOx control technologies are expected to produce waste, whether solid waste 

or wastewater. LoTOx is expected to produce both solid waste and wastewater, but estimates on 

the amount are not available at this time. Spent catalyst for SCR systems must be replaced 

periodically, which becomes solid waste. In addition, some fine particulate matter is produced 

by SCR systems that must be collected by a fabric filter or dry electrostatic precipitator (ESP). 

The particulate matter collected by a fabric filter or dry ESP must be disposed of as solid waste; 

the presence of fine particles from the catalyst may require disposal as a hazardous waste. 

 
123

Table 7.3.4-2. Estimated Energy and Non-Air Environmental Impacts of Potential 

 Emission Control Devices for Kiln #2 at the Mountain Cement Company,

 Laramie Plantx

Energy and Non-Air Pollution Impacts

(per ton of emission reduced)

Unit 

ID

Control 

Technology

Potential 

Emission 

Reductions 

(1000 tons/yr)

Pollutant 

Controlled

Additional 

Fuel 

Requirements 

(%)

Electricity 

Requirements 

(kW-hr) 

Steam 

Requirements 

(lb/hr)

Solid Waste 

Generated 

(ton/hr)

Wastewater 

Produced 

(gal/min)

Kiln 

#2

LNB (indirect) 157-210

NOx

a 182 b b b

LNB (direct) 210 a 182 b b b

Biosolid Injection 262 a b b b b

NOxOUT 183 b b b b b 

CemSTAR 105-314 a b b b b

LoTOx

TM 419-472 b c b d d

SCR 419 b b b e b

SNCR (urea) 183 b d b b b

SNCR (ammonia) 183 b d b b b

Fabric Filter 37 PM10 b d b 1 b

Dry ESP 15 b d b 1 b

Fabric Filter 36-37 PM2.5b d b 1 b

Dry ESP 14-15 b d b 1 b

a - The control technology is expected to improve fuel efficiency.

b - Impact not expected.

c - Electricity requirements are expected to be high, but not enough data to quantify.

d - Technology expected to have an impact, but insufficient data available to evaluate requirements.

e - Spent catalyst will have to be disposed of on occasion. x

All values listed in Table 7.3.4-2 were obtained from the EC/R Incorporated report “Supplementary Information 

for Four-Factor Analyses for Selected Individual Facilities in Wyoming” and is included in Chapter 7 of the 

Wyoming TSD.

• Remaining Equipment Life 

If Mountain Cement chooses to replace kiln #2, then the cost of the control technologies for the 

currently operating kiln would likely be cost prohibitive. 

If Mountain Cement decides not to replace kiln #2, then the remaining life of the kiln would 

likely be indefinite. Under this scenario, the lifetime of the selected control technology could be 

assumed to be equal to or less than the lifetime of the cement kiln. The capital cost of the control 

technology would not have to be amortized over the kiln lifetime, thus eliminating the impact of 

the remaining equipment life on the cost of the control technology. 

The implementation of new control technologies on the cement kiln is discussed in Chapter 8 

(Section 8.3.4), Long-Term Strategy. 

7.3.5 Oil and Gas Exploration and Production Field Operations 

Oil and gas production, which is not limited to just one area of Wyoming, is an important and 

critical component of the state economy. Sources associated with oil and gas production emit 

NOx and PM. Sources include turbines, diesel engines, glycol dehydrators, amine treatment 

units, flares and incinerators. 

Emissions from large stationary oil and gas sources in the WRAP region have been well 

quantified over the years, while smaller field and production sources are not as well understood. 
124

To better understand the emissions from all oil and gas sources across the region, the WRAP 

region instituted a three-phase emission inventory project. Phase I, which was completed in 

2005, was an emission inventory project that estimated regional emissions from oil and gas field 

operations for the first time. Phase II, completed in late 2007, was an effort to more fully 

characterize the oil and gas field operations emissions. The WRAP inventory currently addresses 

only large stationary sources and a consistent reporting system for oil and gas emissions for 

WRAP member states has not yet been developed. Members of the Independent Petroleum 

Association of Mountain States (IPAMS) felt that still more improvement in the accuracy of 

these emission estimates was needed. So, in late 2007, IPAMS initiated a Phase III regional oil 

and gas emission inventory project funded by their organization. The project was undertaken in 

conjunction with the WRAP to assure that the products from Phase III were widely distributed 

among non-industry stakeholders (state/local agencies, tribal air programs, Federal Land 

Managers, environmental groups and EPA). Phase III results will not be ready for this SIP 

review.

While inventory work has not been completed on the oil and gas industry, the WRAP did engage 

EC/R to assist with the four factor analysis for oil and gas. 

EC/R evaluated control technologies for common emission sources in the oil and gas industry: 

reciprocating engines and turbines, process heaters, flares and incinerators, and sulfur recovery 

units. For compressor engines and gas-fueled reciprocating engines, potential control options 

presented by EC/R include air-fuel ratio controls (AFRC), ignition timing retard, low-emission 

combustion (LEC) retrofit, selective catalytic reduction (SCR), selective non-catalytic reduction 

(SNCR), and replacement with electric motors. LEC retrofit technology requires modification of 

the combustion system to increase the air-to-fuel ratio, which creates very lean combustion 

conditions. Currently in Wyoming, many of the rich-burn engines associated with compressor 

stations utilize SNCR in conjunction with AFRC, while lean-burn engines often utilize an 

oxidation catalyst to reduce emissions.

Regulating drill rig engines is problematic for states. Drill rig engines are, for the most part, 

considered mobile sources and emission limits for mobile sources are set by the Federal 

government under Section 202 of the CAA. Several control options exist and include ignition 

timing retard, exhaust gas recirculation, SCR, replacement of Tier 2 engines with Tier 4 engines, 

and diesel oxidation catalyst.

Other common oil and gas exploration and production equipment also have emission control 

device options. Turbine emissions can be controlled by water or steam injection, low NOx

burners, SCR, and water or steam injection with SCR. NOx emission control technologies for 

process heaters include LNB, ultra-low NOx burners (ULNB), LNB with flue gas recirculation 

(FGR), SNCR, SCR, and LNB installed in conjunction with SCR. Glycol circulation rates on 

glycol dehydrators can be optimized to reduce VOC emissions. Control measures for flares, 

incinerators, and sulfur recovery units evaluated by EC/R control only SO2 emissions and are not 

addressed in this SIP. 

NOx emissions vary based on the equipment and fuel source. Emissions from individual natural 

gas-fired turbines at production operations can be as high as 877 tons of NOx per year (tpy), 
125

while emissions from individual natural gas turbines at exploration operations can reach 131 tpy. 

Individual gas reciprocating engines have comparable NOx emissions with up to 700 tpy at 

production operations and 210 tpy at exploration operations. Diesel engine emissions can 

approach 46 tpy for production operations and 10 tpy for exploration operations. 

 

• Cost 

Table 7.3.5-1 lists the various control technologies identified by EC/R for oil and gas field 

operations. Both the capital and annual costs for each technology is dependent on the engine 

size or on the process throughput. For several of the control technologies listed in Table 7.3.5-1, 

cost estimate ranges are provided. The lower end of the cost estimates represent the cost per unit 

for the larger units or higher production due to economy of scale, while the higher end of the cost 

estimates represent the cost per unit for the smaller units or lower production. 

Flares, incinerators, sulfur recovery units, and glycol dehydrators were not included because the 

control technology evaluated by EC/R for those sources were only applicable for SO2 or VOCs, 

which are not addressed by this SIP. 
126

Table 7.3.5-1. Estimated Costs for Oil and Gas Exploration and Production Equipmentx Cost Estimates

Source Type Control Technology

Estimated 

Control 

Efficiency (%)

Pollutant 

Controlled

Estimated

Capital Cost

($/unit)

Annual Cost 

($/year/unit) Units

Cost 

Effectiveness 

($/ton)

Compressor 

Engines

Air-fuel ratio 

control (AFRC) 10-40 NOx 5.3 - 42 0.9 - 6.8 hp 68 - 2,500

Ignition timing 

retard 15-30 NOx N/A 1-3 hp 42 – 1,200

LEC retrofit 80 - 90 NOx 120 – 820 30 – 210 hp 320 – 2,500

SCR 90 NOx 100 – 450 40 – 270 hp 870 – 31,000

SNCR 90 – 99 NOx 17 – 35 3 – 6 hp 16 - 36

Replacement with 

electric motors

100 NOx

120 - 140 38 - 44

100 – 4,700

100 PM10 hp >79,000

100 PM2.5 >79,000

Drilling Rig 

Engines and 

Other 

Engines

Ignition timing 

retard 15 – 30 NOx 16 - 120 14 – 66 hp 1,000 – 2,200

Exhaust gas 

recirculation (EGR) 40 NOx 100 26 – 67 hp 780 – 2,000

SCR 80 – 95 NOx 100 – 2,000 40 – 1,200 hp 3,000 – 7,700

Replacement of 

Tier 2 engines with 

Tier 4

87 NOx

125 20 hp

900 – 2,400

85 PM10 25,000 – 68,000

85 PM2.5 25,000 – 68,000

Diesel oxidation 

catalyst

25 PM10 10 1.7 hp 1,400 25 PM2.5

Turbines

Water or steam 

injection 68 – 80 NOx 4.4 – 16 2 – 5 1000 BTU 560 – 3,100

Low NOx burners 

(LNB) 68 – 84 NOx 8 – 22 2.7 – 8.5 1000 BTU 2,000 – 10,000

SCR 90 NOx 13 – 34 5.1 – 13 1000 BTU 1,000 – 6,700

Water or steam 

injection with SCR 93 – 96 NOx 13 – 34 5.1 – 13 1000 BTU 1,000 – 6,700

Process 

Heaters

LNB 40 NOx 3.8 – 7.6 0.41 – 0.81 1000 BTU 2,100 – 2,800

Ultra-Low NOx

Burners (ULNB) 75 – 85 NOx 4.0 – 13 0.43 – 1.3 1000 BTU 1, 500 – 2,000

LNB and FGR 48 NOx 16 1.7 1000 BTU 2,600

SNCR 60 NOx 10 – 22 1.1 – 2.4 1000 BTU 4,700 – 5,200

SCR 70 – 90 NOx 33 – 48 3.7 – 5.6 1000 BTU 2,900 – 6,700

LNB and SCR 70 – 90 NOx 37 – 55 4 – 6.3 1000 BTU 2,900 – 6,300 x

All values listed in Table 7.3.5-1 were summarized from the EC/R Incorporated report “Supplementary Information 

for Four Factor Analyses by WRAP States” and is included in Chapter 7 of the Wyoming TSD.

Based on available State permitting data, some of the larger compressor engines in the state can 

approach 2,900 hp, while coal bed methane engines can be as small as 98 hp. Some of the 

emissions control technologies for compressor engines, such as SCR, can become quite costly 

based on the horsepower (hp) of the engine. This also holds true for other oil and gas 

exploration and production equipment depending on the engine size or production. Drilling rig 

engines can range from 550 hp for diesel engines up to 2,119 hp for natural gas engines, with 

1,476 hp engines common in the field. Turbines are generally around 112 MMBtu/hr, though 

turbines can be as small as 0.4 MMBtu/hr or as large as 380 MMBtu/hr. Process heaters in 

Wyoming commonly range from 0.87 MMBtu/hr to 1.5 MMBtu/hr, with process heaters having 

a throughput of 0.75 MMBtu/hr being common in the state. 

In the case of compressor engines, many facilities throughout the state have already installed 

control equipment. For lean burn engines, oxidation catalysts are commonly installed while 

SNCR catalysts with AFRC are commonly installed for rich burn engines. 

 
127

• Time Necessary for Compliance

EC/R predicted that up to two years would potentially be required for Wyoming to develop the 

necessary regulations. It is estimated that companies would require a year to procure the 

necessary capital to purchase the control equipment. The time required to design, fabricate, and 

install control technologies vary based on the control technology selected and other factors. It is 

predicted that 13 months would be required for the design, fabrication, and installation of SCR or 

SNCR technology, though some regulators have found that the time required is closer to 18 

months. If multiple sources at a facility are to be controlled, an additional 12 months may be 

required for staging the installation process. 

The implementation of new control technologies for oil and gas operations is discussed in further 

detail in Chapter 8, Long-Term Strategy. 

7.4 309 SIP and 309(g)

51.309(g) allows the State to demonstrate reasonable progress for Wyoming’s seven Class I 

areas by building upon and taking full credit for the strategies already adopted, and taking full 

credit for the strategies already adopted for protecting the 16 Class I areas on the Colorado 

Plateau with a primary emphasis on controlling SO2 and anthropogenic smoke. All of those 

strategies have been submitted to EPA under a 309 SIP. Furthermore, those strategies have been 

included in the WRAP regional modeling demonstration establishing expected visibility 

conditions on the most impaired and least impaired days for all of Wyoming’s Class I areas. A 

comparative review of Wyoming SO2 source impact on the Colorado Plateau Class I areas and 

the Wyoming Class I areas shows that reductions in SO2 have a much greater impact on 

Wyoming Class I areas than those on the Colorado Plateau. This Plan, which is submitted under 

309(g), contains many additional measures focused on controlling NOx and PM. The combined 

SO2 control strategies of the 309 SIP and the 309(g) SIP, which have been modeled by the 

WRAP, provide the basis for established reasonable progress goals in Wyoming’s Class I areas.

7.5 Setting Reasonable Progress Goals

Under Section 308(d)(1) of the Regional Haze Rule, states must “establish goals (expressed in 

deciviews) that provide for reasonable progress towards achieving natural visibility conditions” 

for each Class I area of the state. These RPGs must provide for an improvement in visibility for 

the most impaired visibility days, and ensure no degradation for the least impaired visibility days 

over the same period. The RPGs are interim goals that represent incremental visibility 

improvement over time, in this case out to the year 2018, to be compared to the 2018 Uniform 

Rate of Progress (URP) glide slope. Based on the steps outlined in Section 7.2 and the FourFactor Analysis in Section 7.3, the Division has established RPGs for each of Wyoming’s seven 

Class I areas, as described below. These RPGs are based primarily on results of the CMAQ 

modeling described in Section 5.1.2, and on the four-factor analysis on major source categories. 

These goals do not reflect additional improvements in visibility from controls that were not 

included in the 2018 WRAP modeling. It would be difficult to set goals lower than the 

anticipated target without additional modeling.
128

Table 7.5-1 shows that for the 20% best days, the RPGs show an improvement over baseline 

conditions, and thus ensure no visibility degradation. For the 20% worst days, the RPGs are 

short of the 2018 URP, but can be justified based on the demonstration provided in Section 7.6. 

Table 7.5-1. Reasonable Progress Goals for 20% Worst Days and 20% Best Days for 

 Wyoming Class I Areas 

Wyoming

Class I Area

20% Worst Days 20% Best Days

Baseline

Condition

(dv)

2018

Uniform

Progress

Goal

(dv)

2018

Reasonable

Progress

Goal

(dv)

Baseline

Condition

(dv)

2018

Reasonable

Progress

Goal

(dv)

Yellowstone National Park

Grand Teton National Park

Teton Wilderness

11.8 10.5 11.2 2.6 2.4

North Absaroka Wilderness

Washakie Wilderness 11.5 10.4 11.0 2.0 2.0

Bridger Wilderness

Fitzpatrick Wilderness 11.1 10.0 10.6 2.1 2.0

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 

7.6 Demonstration That the RPGs for 20 Percent Best and Worst Days are Reasonable 

EPA guidance indicates that “States may establish an RPG that provides for greater, lesser or 

equivalent visibility improvement as that described by the glidepath.” The 2018 RPGs identified 

in Table 7.5-1 for 20 percent worst days show an improvement in visibility, although less than 

the 2018 URP. The Division believes that RPGs are reasonable based on the following factors: 

1. Emissions from natural sources greatly affect the State’s ability to meet the 2018 

deciview URP goal. The analysis in Chapters 4 and 5 of this Plan containing summaries 

of emissions data, source apportionment, and modeling shows the contribution from 

natural or nonanthropogenic sources, such as natural wildfire and windblown dust is the 

primary reason for not achieving the 2018 URP in Wyoming’s Class I areas. The State 

has little or no control over OC, EC, PM2.5, coarse PM and soil emissions associated with 

natural fire and windblown dust. Prolonged droughts in the West have resulted in 

extensive wildfires and increased dust emissions. The idea of setting deciview URP 

goals was developed before the causes of haze in the West were well understood. The 

extensive technical analysis of the causes of haze conducted by the WRAP has led to a 

better understanding of the role of wildfire and dust in visibility impairment. As long as 

there are wildfires in the Western United States, there will be significant impact to 

visibility in Class I areas and there is little states can do about it. 

2. Emissions from sources outside the WRAP modeling domain (international emissions) 

also affect the State’s ability to meet the 2018 URP goal. The analysis in Chapter 5 of 

this Plan containing monitoring and modeling results shows the emissions from 

international sources are a significant contributor to sulfate and nitrate concentrations at 

the monitors in most Western Class I areas, including those in Wyoming. The State has 

little or no control over emissions coming from other countries in the world. 
129

3. Major reductions in SO2 emissions established in the previously submitted Wyoming 309 

SIP demonstrate the State’s commitment to reducing visibility impairment. Tremendous 

progress has already been made toward capping and controlling SO2 emissions from 

major point sources from the four states that have elected to participate in the Western 

Backstop Trading Program, including Wyoming. 

4. The largest point source category of NOx emissions is coal-fired power plants. In 

Wyoming, significant reductions from these plants will be achieved through the 

implementation of BART levels established in this Plan, as well as additional reductions 

committed to in the long-term strategy. 

5. The second largest category of stationary sources in the West is oil and gas development 

and production. Increased oil and gas development is expected in many areas of the 

West, due in large part to increased leasing to oil and gas operators on Federal land. The 

WRAP has developed the first comprehensive oil and gas inventory in the Western 

United States, and many states are moving forward with evaluating control options. 

Wyoming is evaluating and testing many of the control strategies, but the specific 

strategies are not ready for incorporation into this first round of regional haze SIPs. 

Control options for ozone are being evaluated simultaneously and the State believes that 

many co-benefits from controlling emissions for ozone will be realized under the regional 

haze program. Numerous additional emission reductions from oil and gas are expected 

over the next ten-year period. 

6. Wyoming Class I areas have some of the cleanest air in the United States. The haziest 

days in Wyoming generally have the same level of visibility impairment as the clearest 

days in the Eastern United States. Monitors at visibility sites in Wyoming Class I areas 

show fine particle loadings that are a fraction of those in the East, and Rayleigh, or 

natural light scattering, dominates the clearest days in the West. Therefore, it is more 

difficult to show improvement in visibility over time in Wyoming than it is in an Eastern 

state because the state is starting out so clean.

7. Wyoming is not alone in setting reasonable progress goals which do not achieve the 

uniform rate of progress. The vast majority of sites in the Western United States will not 

come close to URP goals primarily because controllable emissions are only a small 

fraction of the total contribution to visibility impairment in the Western Class I areas.5

8. Reasonable progress goals in Wyoming have been based on the control strategies of two 

major State Implementation Plans - 309 and 309(g). Major work undertaken by the State 

of Wyoming along with three other Western states and one local entity to cap and reduce 

SO2 emissions represents major progress towards controlling SO2. Capping and reducing 

SO2 from all of Wyoming’s 100-ton sources has a bigger impact on nearby Wyoming 

Class I areas than Class I areas on the Colorado Plateau. The 309 program provides a 

declining cap for all non-BART 100-ton SO2 sources through 2018. Visibility 

 

5 Source Contributions to Visibility Impairment in the Southeastern and Western United States (Patricia Brewer and 

Tom Moore)
130

improvement, as it relates to sulfate extinction, has been demonstrated at all of 

Wyoming’s Class I areas as a result of the application of the 309 program. This visibility 

information is shown in Chapter 6 of this SIP in Table 6.2-2. Additional work completed 

for the 309(g) requirements, which is spelled out in great detail in this SIP, provides still 

further improvement.

9. Wyoming air quality monitoring for visibility pollutants has not shown a trend toward 

degraded visibility resulting from anthropogenic sources thus far, in spite of industrial 

growth. Time series plots of individual chemical species measured for visibility on the 

worst days are shown below. While organic carbon measurements (primarily from forest 

fires) show a high degree of variability from year to year, sulfates and nitrates (primarily 

from anthropogenic sources) have not shown a significant degree of variation over time.

Figure 7.6-1. Time Series Plot by Pollutant on 20% Worst Days for Yellowstone NP,

 Grand Teton NP, and Teton Wilderness Area 

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
131

Figure 7.6-2. Time Series Plot by Pollutant on 20% Worst Days for North Absaroka and 

 Washakie Wilderness Areas

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

Figure 7.6-3. Time Series Plot by Pollutant on 20% Worst Days for Bridger and 

 Fitzpatrick Wilderness Areas

(WRAP TSS - http://vista.cira.colostate.edu/tss/) 
132

CHAPTER 8

LONG-TERM STRATEGY

8.1 Overview 

The Regional Haze Rule requires states to submit a 10-15 year long-term strategy (LTS) to 

address regional haze visibility impairment in each Class I area in the state, and for each Class I 

area outside the state which may be affected by emissions from the state. The LTS must include 

enforceable measures necessary to achieve reasonable progress goals, and identify all 

anthropogenic sources of visibility impairment considered by the state in developing the longterm strategy. Where the state contributes to Class I visibility impairment in other states it must 

consult with those states and develop coordinated emission management strategies, and 

demonstrate it has included all measures necessary to obtain its share of the emission reductions. 

If the state has participated in a regional planning process, the state must include measures 

needed to achieve its obligations agreed upon through that process. 

8.1.1 Summary of all Anthropogenic Sources of Visibility Impairment Considered in 

 Developing the Long-Term Strategy

Section 51.308(d)(3)(iv) of the Regional Haze Rule requires the identification of “all 

anthropogenic sources of visibility impairment considered by the State when developing its longterm strategy.” Chapter 4 of this Plan describes Wyoming statewide emissions, including 

projections of emissions reductions from anthropogenic sources from 2002 to 2018. Chapter 5 

of this Plan provides source apportionment results, including projected reductions from 

anthropogenic sources during the same period. Chapter 5 addresses anthropogenic sources from 

all potential sources in the world. Chapter 7 includes the results of a screening analysis which 

identifies the major anthropogenic sources in the State of Wyoming. Together, these three

chapters show the major anthropogenic sources affecting regional haze in Wyoming and in the 

West. Chapter 7 further describes the major anthropogenic source categories evaluated through 

the four-factor analysis.

8.1.2 Summary of Interstate Transport and Contribution

Sections 51.308(d)(3)(i) and (ii) of the Regional Haze Rule requires that the Long-Term Strategy 

address the contribution of interstate transport of haze pollutants between states. Chapter 4 of 

this Plan illustrated Wyoming statewide emissions, while Chapter 5 identified interstate transport 

of pollutants and larger source categories based on source apportionment results. 

8.1.2.1 Other States’ Class I Areas Affected by Wyoming Emissions

Wyoming used baseline period visibility data from the IMPROVE monitors along with the 

WRAP baseline modeling results to estimate Wyoming’s emissions impact on neighboring 

states’ Class I areas (see Figure 8.1.2.1-1). Wyoming focused on anthropogenic emissions 

transported to other states, primarily sulfates and nitrates. 
133

 

Yellowstone NP

Northern Cheyenne Indian Reservation

Medicine Lake National Wildlife Refuge

UL Bend National Wildlife Refuge

Badlands NP

Wind Cave NP

North Absaroka Wilderness

Washakie Wilderness Grand Teton NP

Fitzpatrick Wilderness

Bridger Wilderness

Teton Wilderness (Red)

Glacier National Park

Gates of the Mountains Wilderness

Bob Marshall Wilderness

Mission Mountains Wilderness

Scapegoat Wilderness

Anaconda Pintler Wilderness

Selway-Bitterroot Wilderness

Sawtooth Wilderness

Craters of the Moon NM

Mount Zirkel Wilderness Rawah Wilderness

Rocky Mountain NP

Flat Tops Wilderness

Eagles Nest Wilderness

Maroon Bells-Snowmass Wilderness

West Elk Wilderness

Black Canyon of the Gunnison

La Garita Wilderness

Weminuche Wilderness Zion National Park Bryce Canyon National Park

Capitol Reef NP

Canyonlands NP

Arches NP

Hells Canyon

Wilderness

Mesa Verde NP

Wyoming

South Dakota

Montana

Idaho

Utah

Colorado

Cabinet Mountains

Wilderness

Red Rock Lakes

Great Sand Dunes NP

Theodore Roosevelt National Park

Lostwood National Wildlife Refuge

North Dakota

Figure 8.1.2.1-1

Wyoming, South Dakota, Montana, Idaho,

Utah, North Dakota and Colorado Class I Areas
134

In the table below, the first column shows the contribution of nitrates to visibility impairment at 

surrounding Class I areas calculated from the IMPROVE monitoring data measured during the 

baseline period to provide perspective on the role of nitrates to overall impairment. The second 

column shows Wyoming’s contribution to particle mass calculated from the modeled 

concentrations of nitrate for the baseline years. The table below illustrates two things: 1) the 

role of nitrates in visibility impairment at the Class I area, and 2) the probable share of Wyoming 

emissions contributing to the pollutant species. 

Table 8.1.2.1-1. Nitrate Contribution to Haze in Baseline Years

State and Mandatory Class I Area

2000-2004

Average Annual Nitrate 

Share of Particle Light

Extinction

(measured values)

2000-2004

Wyoming’s Average 

Annual Share of Nitrate

Concentration

(based on modeling)

Worst Days Best Days Worst Days Best Days

South Dakota

Wind Cave National Park 14% 5% 18% 34%

Badlands National Park 10% 6% 12% 34%

Colorado

Mount Zirkel/Rawah Wilderness* 7% 4% 10% 8%

Rocky Mountain National Park 13% 3% 10% 8%

Utah

Arches/Canyonlands National Park* 9% 4% 2% 3%

Idaho

Craters of the Moon National Monument 27% 8% 3% <1%

Montana

Anaconda-Pintler/Selway-Bitterroot* 3% 3% 3% <1%

Gates of the Mountains Wilderness 6% 4% 2% <1%

North Dakota

Theodore Roosevelt National Park 22% 7% 4% 7%

Lostwood National Wildlife Refuge 31% 8% 3% 2%

*These Class I areas share one monitor.

When modeled, Wyoming NOx emissions contribute up to 18 percent of the nitrate 

concentrations at some neighboring states on worst days. As shown in the above table, however, 

nitrate contributes only 14 percent of the visibility impairment at the corresponding nearest Class 

I areas in neighboring states. Hence, only a small portion of out-of-state visibility degradation is 

due to nitrate formed from Wyoming emissions. By 2018, NOx emissions from Wyoming are 

projected by the WRAP to decrease by 39,861 tons, which will help reduce Wyoming’s impact 

to out of state Class I areas. 
135

Table 8.1.2.1-2. Sulfate Contribution to Haze in Baseline Years

State and Mandatory Class I Area

2000-2004

Average Annual Sulfate 

Share of Particle Light

Extinction

(measured values)

2000-2004

Wyoming’s Average 

Annual Share of Sulfate

Concentration

(based on modeling)

Worst Days Best Days Worst Days Best Days

South Dakota

Wind Cave National Park 26% 15% 11% 22%

Badlands National Park 33% 17% 6% 20%

Colorado

Mount Zirkel/Rawah Wilderness* 17% 13% 7% 12%

Rocky Mountain National Park 19% 11% 5% 10%

Utah

Arches/Canyonlands National Park* 18% 15% 3% 8%

Idaho

Craters of the Moon National Monument 14% 10% 2% 1%

Montana

Anaconda-Pintler/Selway-Bitterroot* 11% 8% 2% <1%

Gates of the Mountains Wilderness 17% 8% 1% <1%

North Dakota

Theodore Roosevelt National Park 28% 17% 2% 1%

Lostwood National Wildlife Refuge 29% 19% 1% <1%

* These Class I areas share one monitor.

When modeled, Wyoming sulfate emissions contribute up to 11 percent of the sulfate 

concentrations at some neighboring states on worst days. As shown in the above table, sulfate 

contributes 26 percent of the visibility impairment at the corresponding nearest Class I areas in 

neighboring states. By 2018, SO2 emissions from Wyoming are projected by the WRAP to 

decrease by 22,794 tons, which will help reduce Wyoming’s impact on out of state Class I areas.

8.1.2.2 Wyoming Class I Areas Affected by Other States, Nations and Areas of the World 

The contribution of neighboring states of South Dakota, Colorado, Utah, Idaho and Montana to 

Wyoming Class I areas was examined to determine where significant emissions might be coming 

from. In the case of both nitrates and sulfates on best and worst days, the most significant 

impacts on all Wyoming Class I areas came from sources outside the modeling domain. These 

would be emissions from other parts of the world. This review has focused on nitrates and 

sulfates since those emissions tend to focus on anthropogenic sources. Data for this impact 

analysis comes from the PSAT runs performed by the WRAP and documented in the TSS. 
136

Yellowstone National Park, Grand Teton National Park, and Teton Wilderness Area

• Sulfates

On the best days in the baseline years, 50 percent of the sulfates come from sources outside of 

the modeling domain. The next largest contribution of sulfates comes from Idaho showing a 14 

percent contribution to sulfate extinction in the baseline years. Sulfates, overall, contribute 

11% to visibility impairment in these Class I areas on the best days. Similarly, on the worst 

days, most of the impact (47%) comes from sources outside the modeling domain. The next 

largest contribution is from Idaho showing an eight percent contribution to sulfate extinction in 

the baseline years. Sulfates, overall, contribute 12% to visibility impairment in these Class I

areas on the worst days. Other states surrounding Wyoming showed smaller contributions (less 

than five percent). Canadian impacts were between six and nine percent on the worst and best 

days, respectively. Wyoming has worked with Idaho through the WRAP process and believes 

that Idaho is working to reduce sulfate impacts to these Class I areas. Idaho is projected by the 

WRAP to reduce sulfate related emissions by 13,272 tons by 2018. 

• Nitrates

On the best days in the baseline years, 25 percent of the nitrates come from sources outside the 

modeling domain. 22 percent is attributed to Idaho and approximately 14 percent to Utah. Other 

states surrounding Wyoming, and including Wyoming, showed less than five percent impact. 

Overall impact of nitrates on visibility impairment on the best days is six percent in these Class I

areas. On the worst days in the baseline years, 31 percent of the nitrates come from sources 

outside of the modeling domain, and 28 percent is attributed to Idaho sources. Other states 

surrounding Wyoming, and including Wyoming, showed impacts between zero and eight 

percent. Overall impacts from nitrates on worst days in these Class I areas is five percent. 

Wyoming has worked with both Idaho and Utah through the WRAP process and believes that 

both states are working to reduce nitrate impacts to these Class I areas. Idaho is projected by the 

WRAP to reduce nitrate causing emissions by 32,418 tons by 2018 and Utah is projected by the 

WRAP to reduce nitrate causing emissions by 71,678 tons by 2018. 

Bridger and Fitzpatrick Wilderness Areas

• Sulfates

On the best days in the baseline years, 56 percent of the sulfates come from sources outside of 

the modeling domain. The next largest contribution of sulfates comes from Idaho, showing an 

18 percent contribution to sulfate extinction in the baseline years. Other states, including 

Wyoming, show less than nine percent contribution. Sulfates, overall, contribute 12% to 

visibility impairment in these Class I areas on the best days. Similarly, on the worst days, most 

of the impact (31%) comes from sources outside the modeling domain. The next largest 

contribution is from Wyoming, showing a 15 percent impact to sulfate extinction in the baseline 

years. Other states in the region showed less than eight percent impact. Sulfates, overall, 

contribute 16% to visibility impairment in these Class I areas on the worst days. Wyoming has 

worked with Idaho through the WRAP process and believes that Idaho is working to reduce 
137

sulfate impacts to these Class I areas. Idaho is projected by the WRAP to reduce sulfate related 

emissions by 13,272 tons by 2018. Emission reductions from Wyoming sources are addressed 

through the 309 SIP, previously submitted to EPA. 

• Nitrates

On the best days in the baseline years, 30 percent of the nitrates come from sources outside the 

modeling domain. 24 percent is attributed to Utah and approximately 15 percent to Idaho. Other 

states surrounding Wyoming, and including Wyoming, showed less than nine percent impact. 

Overall impact of nitrates on visibility impairment on the best days is three percent in these Class 

I areas. On the worst days in the baseline years, 22 percent of the nitrates come from sources 

outside of the modeling domain, and 19 percent is attributed to Wyoming. Utah and Idaho are 

estimated to contribute 16 and 11 percent, respectively. Other states surrounding Wyoming 

showed impacts between one and seven percent. Overall impacts from nitrates on worst days in 

these Class I areas is five percent. Wyoming has worked with both Idaho and Utah through the 

WRAP process and believes that both states are working to reduce nitrate impacts to these Class 

I areas. Idaho is projected by the WRAP to reduce nitrate causing emissions by 32,418 tons by 

2018 and Utah is projected by the WRAP to reduce nitrate causing emissions by 71,678 tons by 

2018. Wyoming is committed to reducing projected WRAP emissions by at least 39,861 tons by 

2018. 

North Absaroka and Washakie Wilderness Areas

• Sulfates

On the best days in the baseline years, 50 percent of the sulfates come from sources outside of 

the modeling domain. The next largest contribution of sulfates comes from Canada, showing an 

18 percent contribution to sulfate extinction in the baseline years. Other states, including 

Wyoming, show less than ten percent contribution. Sulfates, overall, contribute nine percent to 

visibility impairment in these Class I areas on the best days. Similarly, on the worst days, most 

of the impact (50%) comes from sources outside the modeling domain. The next largest 

contribution is from Canada, showing a 13 percent contribution to sulfate extinction in the 

baseline years. States in the region showed less than seven percent impact. Sulfates, overall, 

contribute 15% to visibility impairment in these Class I areas on the worst days. EPA is working 

with Canadian officials to develop cooperative strategies for reducing sulfate emissions from 

Canada and the U.S. 

• Nitrates

On the best days in the baseline years, 29 percent of the nitrates come from sources outside the 

modeling domain. 14 percent is attributed to Idaho, 13 percent to Canada, and approximately 11 

percent from Utah. Other states surrounding Wyoming, and including Wyoming, showed less 

than seven percent impact. Overall impact of nitrates on visibility impairment on the best days is 

three percent in these Class I areas. On the worst days in the baseline years, 31 percent of the 

nitrates come from sources outside of the modeling domain, and 17 percent is attributed to Idaho. 

Montana and Canada are estimated to contribute 15 and 12 percent, respectively. Other states 
138

surrounding Wyoming showed impacts between zero and five percent. Overall impacts from 

nitrates on worst days in these Class I areas is five percent. Wyoming has worked with Idaho 

through the WRAP process and believes that Idaho is working to reduce nitrate impacts to these 

Class I areas. Idaho is projected to reduce nitrate causing emissions by 32,418 tons by 2018. 

Montana’s emissions are being addressed by EPA through a Federal Implementation Plan, and 

nitrate emissions are projected to decrease by 63,099 tons by 2018. EPA is also working with 

Canadian officials to develop cooperative strategies for reducing nitrate emissions from Canada 

and the U.S. 

The Division consulted with neighboring states as part of this review, and discussed the need for 

coordinated strategies to address interstate transport. Based on this consultation, no significant 

contributions were identified that supported developing new interstate strategies. Both Wyoming 

and neighboring states agreed that the implementation of BART and other existing measures in 

state regional haze plans were sufficient to address the contributions discussed below. This 

interstate consultation is an on-going process and continuing commitment between states. See 

Chapter 11 for further information. 

8.1.3 Summary of Interstate Consultation

In addition to evaluating interstate transport, the affected states are required to consult with each 

other under Section 51.308(d)(3)(i), in order to develop coordinated emission management 

strategies. See Section 11.1 for information on the state-to-state consultation process. 

8.1.4 Estimated International and Global Contribution to Wyoming Class I Areas

Although not specifically addressed under the Regional Haze Rule in terms of interstate 

transport, it is important to identify the contribution to visibility impairment in Wyoming from 

international sources, such as Canada and Mexico, offshore marine shipping in the Pacific 

Ocean, and “global” sources of haze. The PSAT and WEP results in Chapter 5 describe the 

amount of contribution to visibility impairment in Wyoming from Canada, Mexico, offshore 

marine shipping in the Pacific and general global or “outside domain” sources. Because the 

State of Wyoming does not have any authority over any of the above-mentioned international 

sources, the Division is not pursuing any new strategy for haze impacts due to international 

sources.

The following text was extracted from EPA responses to state questions posed by the WRAP 

Implementation Work Group in March 2007: 

The U.S. and Canada have been working on addressing transboundary emissions issues through 

the bilateral 1991 Canada-United States Air Quality Agreement. Information, including progress 

reports and articles, on this agreement can be found at 

http://www.epa.gov/airmarkets/resource/usaqa-resource.html. Under the agreement, Canada and 

the United States have looked at addressing transboundary air pollution, namely, acid rain and 

ground-level ozone. Over the last two years, Canada and the United States have continued to 

successfully reduce their emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx), the major 

contributors to acid rain and also to regional haze. Both countries have also made considerable 
139

progress in meeting the requirements of the Ozone Annex to reduce emissions of NOx and 

volatile organic compounds (VOCs), the precursors to ground-level ozone. Canada and the 

United States have focused their actions on reducing these emissions from major sources such as 

electric generating units, industrial sources, and on-road and nonroad transportation. 

This Agreement has provided important opportunities for collaboration between Canada and the 

United States and has produced impressive results, not just in environmental improvements, but 

also in diplomacy and working relationships. Both countries rely on the Agreement as the 

mechanism to address air pollution issues and are committed to its continuing viability and 

relevance as new bilateral issues emerge. The Agreement’s flexibility provides opportunities to 

go beyond the challenges identified by the Acid Rain and Ozone annexes, and the Parties look 

forward to considering whether and how to address bilateral issues associated with particulate 

matter, mercury, and other air pollutants.

EPA Region 10 has been meeting with their counterparts in the British Columbia Ministry of 

Environment for the past five years to identify air quality issues in the Georgia-Basin-Puget 

Sound Airshed, and to develop an International Airshed Strategy (IAS) to address these issues. 

The IAS includes protection of visibility as a goal, and the Canadian-United States Air Quality 

Agreement also addresses visibility. At the most recent IAS meeting in January 2007, the air 

program director of the BC Ministry of Environment gave a presentation on the process for 

developing a visibility rule in BC. This rule would be the first of its type in Canada and could be 

a model for the rest of Canada. This BC visibility rule would establish a visibility management 

framework and identify policies needed to achieve visibility protection. A Discussion Paper is 

being developed on this topic and will be the focus of a workshop this spring with 

representatives from Canadian air quality agencies, Canadian Tourism, Parks (National and 

Provincial), Forestry, U.S. EPA, Washington Dept. of Ecology, and U.S. National Park Service. 

The relationship between the air quality improvement programs in Mexico and the United States 

received formal recognition through the Agreement between the United States and Mexico for 

Cooperation on the Environment on the U.S.-Mexico Border (the La Paz Agreement of 1983). 

This recognition provided the authority for EPA and Mexico’s Environmental Ministry to 

conduct cooperative activities to reduce air pollution. In September 1989 the two countries 

signed Annex V to the La Paz Agreement through which they agreed to cooperatively monitor 

air quality in sister cities along the U.S.-Mexico border; Annex V was formally expanded in 

1996. In February 1992, the environmental authorities of both Federal governments released the

Integrated Border Environmental Plan for the U.S.-Mexico Area (IBEP). The IBEP, a two-year 

plan, was the first bi-national Federal initiative created under the assumption that increased 

liberalization of trade would place additional stress on the environment and human health along 

the border. The Border XXI Program was initiated in 1996 to build on the experiences of and 

improve the specific efforts undertaken under the IBEP and earlier environmental agreements.

Pursuant to the La Paz Agreement of 1983, the Administrator of the U.S. Environmental 

Protection Agency (U.S. EPA) and the Secretary of the Secretariat for the Environment and 

Natural Resources (SEMARNAT) agreed on October 2001 to work jointly with the ten border 

states and the U.S. border tribes to develop a new bi-national ten year plan to improve the 

environment and reduce the highest public health risks on the U.S.-Mexico border. On April 4, 
140

2003, the representatives of the U.S. EPA, the Secretary of the Secretariat for the Environment 

and Natural Resources (SEMARNAT), the ten Border States, and the 26 U.S. Tribes, met in 

Tijuana, Baja California, Mexico to mark the beginning of a ten year joint effort, the Border 

2012: U.S.-Mexico Environmental Program replacing the Border XXI Program. 

The United States and Mexico, in partnership with border tribal, state, and local governments, 

have worked to increase the knowledge about air pollution sources and their impacts on both 

sides of the border, establish monitoring networks in several key areas, conduct emissions 

inventories, and build local capacity through training. 

Pollutants from a number of sources including motor vehicles, power plants and industrial 

facilities, agricultural operations, mining, dust from unpaved roads, and open burning have 

affected urban and regional air quality along the U.S.-Mexico border. The most common and 

damaging pollutants from these sources include sulfur dioxide, suspended particulate matter 

(PM10 and PM2.5), nitrogen dioxide, ground-level ozone, and carbon monoxide. 

To provide technical assistance about air quality planning and management to government, 

academia, industry, and the general public in the border region, the U.S. and Mexico established 

the Centro de Informacion sobre Contaminacion de Aire (CICA, or Border Information Center 

on Air Pollution). The CICA Program, which is implemented by the Clean Air Technology 

Center of EPA’s Office of Air Quality Planning and Standards, has established a website at 

http://www.epa.gov/ttn/catc/cica. 

The Big Bend Regional Aerosol and Visibility Observational (BRAVO) Study was conducted to 

quantify the contribution to visibility degradation at Big Bend National Park (BBNP) from 

various air pollution source regions and source types in the U.S. and Mexico. The study 

included evaluation of the impacts from the Carbon 1-2 power plants in Coahuila, 18 miles from 

the U.S. border. Findings from the BRAVO study can be found at 

http://www2.nature.nps.gov/air/studies/bravo/index.htm. 

Beginning in 2003 an effort was undertaken to understand better the smoke/haze from spring 

burning in Central America/Mexico, which prompted State Department of Health alerts for up to 

70% of the population of Texas on some days. Components of this effort include an ambient 

study of particle chemical constituents to determine the sources of haze; remote sensing analysis 

to evaluate locations of the burning and to assess the potential seriousness of such burning to 

transport of particles in Texas; and on-the-ground assessment of ways to fight the fires and 

mitigate damage.

Under the Border 2012 Program bi-national efforts have continued with the transfer of the 

northern Baja California network to the State of Baja California, update of existing emissions 

inventories, and the completion of the first Mexico National Emissions Inventory. 

Additionally, the United States and Mexico in partnership with border tribal, state, and local 

governments, are working together on projects such as retrofitting diesel trucks and school buses 

with either diesel oxidation catalysts or diesel particulate filters to operate on ultra low sulfur 
141

diesel fuel, constructing “lower polluting” or “environmentally friendly” brick kilns, and road 

paving to reduce the levels of particulate matter in the border region.

8.2 Required Factors for the Long-Term Strategy

As required in Section 51.308(d)(3)(v) of the Regional Haze Rule, the State must consider, at a 

minimum, the following factors: 1) emission reductions due to ongoing air pollution control 

programs; 2) measures to mitigate the impacts of construction activities; 3) emission limitations 

and schedules for compliance; 4) source retirement and replacement schedules; 5) smoke 

management techniques for agricultural and forestry burning; 6) the enforceability of emission 

limitations and control measures; and 7) the anticipated net effect on visibility over the period of 

the long-term strategy. These factors are discussed in the following pages along with all 

measures to mitigate the impacts of anthropogenic sources. The seventh factor is discussed at 

the end of the Long-Term Strategy Chapter.

8.2.1 Emission Reductions Due to Ongoing Air Pollution Control Programs

The following summary describes ongoing programs and regulations in Wyoming that directly 

protect visibility, or can be expected to improve visibility in Wyoming Class I areas, by reducing 

emissions in general. This summary does not attempt to estimate the actual improvements in 

visibility that will occur, as many of the benefits are secondary to the primary air pollution 

objective of these programs/rules, and consequently would be extremely difficult to quantify due 

to the technical complexity and limitations in current assessment techniques. 

8.2.1.1 New Source Review Program

The New Source Review (NSR) Program is a permit program for the construction of new 

sources and modification of existing sources as established by WAQSR Chapter 6, Section 2, 

Permit requirements for construction, modification and operation and Chapter 6, Section 4, 

Prevention of significant deterioration. Section 2 of Chapter 6 first became a State rule in 1974, 

with the most recent revision being in March of 2000. Section 2 was submitted to EPA on 

September 12, 2003, approved by EPA on July 28, 2004, and became effective on August 27, 

2004. The primary purpose of the NSR Program is to assure compliance with ambient standards 

set to protect public health, assure that Best Available Control Technology (BACT) is utilized to 

reduce and eliminate air pollution emissions, and to prevent deterioration of clean air areas. Any 

amount of air contaminant emissions from a facility subjects it to Wyoming’s NSR Program.

8.2.1.1.1 Prevention of Significant Deterioration (PSD) Program

Generally, Wyoming considers its Prevention of Significant Deterioration (PSD) program as 

being protective of visibility impairment from proposed major stationary sources or major 

modifications to existing facilities. Wyoming has a fully-approved PSD program, and has 

successfully implemented this program for many years. Wyoming’s PSD rules (Chapter 6, 

Section 4, of the Wyoming Air Quality Standards and Regulations (WAQSR)) were revised 

effective October 6, 2006, to conform with Federal NSR Reform rules. These changes were 
142

submitted to EPA on December 13, 2006, approved by EPA on July 16, 2008, and became 

effective on August 15, 2008. 

8.2.1.1.2 Minor Source BACT Program

The BACT process is most appropriately defined as the elimination of pollutants from being 

emitted into the air whenever technically and economically feasible to do so. For example, by 

application of minor source BACT, the Division has required controls of NOx and formaldehyde 

in coal bed methane (CBM) development and controls of NOx, VOC and Hazardous Air 

Pollutant (HAP) emissions in oil and gas production development. The Division takes the Staterequired BACT review in minor source permitting actions very seriously, as the bulk of the 

Division’s workload is made up of minor sources. 

The Division will continue to review BACT considerations on each source type and size on a 

case-by-case basis with consideration to the technical practicability and economic reasonableness 

of eliminating or reducing the emissions from the proposed facility. The application of BACT in 

the minor source permitting program has resulted in minimized emissions in the state as a whole 

and will continue to do so as the Division continues to receive NSR permit applications for new 

and modified sources. 

8.2.1.2 Title V Operating Permit Program

As required by Title V of the Clean Air Act Amendments of 1990 and the implementing 

regulations in 40 CFR part 70, Wyoming established an Operating Permit Program under 

Chapter 6, Section 3 of the WAQSR. Wyoming’s proposed program was submitted to the 

Environmental Protection Agency (EPA) for approval on November 22, 1993. Notice of Interim 

Approval was published in the Federal Register on January 19, 1995. Final EPA approval of the 

Wyoming Operating Permit Program was published on February 22, 1999, and the approval was 

effective April 23, 1999. 

A Title V Operating Permit consolidates all air quality regulatory requirements in a single 

document, so a permittee can clearly determine compliance with the air quality environmental 

laws governing its operation. The Title V Operating Permit also establishes appropriate 

compliance assurance monitoring on a pollutant-by-pollutant basis for large emission sources 

with add-on pollution control equipment, and/or establishes periodic monitoring for other 

regulated pollutants. The process of issuing the Operating Permit is designed to allow 

participation by the public, the EPA and nearby states to avoid misinterpretation of air quality 

regulatory requirements. This permitting is done to enhance enforceability by clearly defining 

the playing field for all concerned parties, such that all regulated industry is governed by the 

same rules. These permits are issued for a term of five years and must be renewed and updated 

to incorporate current regulatory requirements. Nationally, this program is intended to set 

minimum standards for all states to implement, in an attempt to foster consistency in air quality 

permitting from state to state. The Operating Permit Program is intended to be self supporting, 

and states are required under the Clean Air Act to charge regulated industry fees based upon their 

actual air pollutant emissions on an annual basis; thus, Title V permittees pay for the operation of 

the regulating program.
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The Operating Permit Program currently affects only major sources of air pollution operating in 

the State. A major source is defined as a source which emits, or has the potential to emit, 100 

tons per year of an air pollutant, or any source which emits, or has the potential to emit, 10 tons 

per year of an individual hazardous air pollutant (or 25 tons per year of any combination of 

hazardous air pollutants) which has been listed pursuant to section 112(b) of the Clean Air Act. 

The number of Title V sources within the State is highly variable but has typically ranged from 

150 to 160 sources at any given time. 

In December of 2000, WAQSR Chapter 6, Section 3 Operating permits, was revised to 

incorporate compliance assurance monitoring (CAM). CAM is intended to provide a reasonable 

assurance of compliance with applicable requirements under the Clean Air Act for large 

emission units that rely on pollution control device equipment to achieve compliance. 

Monitoring is conducted to determine that control devices, once installed or otherwise employed, 

are properly operated and maintained so that they continue to achieve a level of control that 

complies with applicable requirements. The Division is addressing the complex implementation 

of CAM in renewals, significant modifications and new permits, as applicable. The 

implementation of CAM will result in documenting continued operation of control devices, 

within ranges of specified indicators of performance, that are designed to provide reasonable 

assurance of compliance with applicable requirements.

8.2.1.3 New Source Performance Standards (NSPS)

The Air Quality Division annually incorporates by reference the Federal New Source 

Performance Standards (NSPS). These standards are incorporated via the Wyoming Air Quality 

Standards and Regulations, Chapter 5, Section 2. Section 2 first became an effective State rule 

in November 1976, with the latest revision becoming effective in May 2008. Section 2 was last 

submitted to the EPA on August 27, 2008, approved by EPA on March 9, 2009, and became 

effective on March 9, 2009. The list of NSPS incorporated by reference include: 

 40 CFR part 60, Subpart D - Standards of Performance for Fossil-Fuel- 

 Fired Steam Generators for Which

 Construction is Commenced After August

 17, 1971 

 40 CFR part 60, Subpart Da - Standards of Performance for Electric

 Utility Steam Generating Units for Which

 Construction is Commenced After 

 September 18, 1978 

 40 CFR part 60, Subpart Db - Standards of performance for Industrial- 

 Commercial-Institutional Steam Generating

Units

 
144

 40 CFR part 60, Subpart Dc - Standards of Performance for Small

 Industrial-Commercial-Institutional Steam

 Generating Units

 40 CFR part 60, Subpart E - Standards of Performance for Incinerators

 40 CFR part 60, Subpart Ea - Standards of Performance for Municipal 

 Waste Combustors for Which Construction 

 is Commenced After December 20, 1989 

 and on or Before September 20, 1994 

 40 CFR part 60, Subpart Eb - Standards of Performance for Large

 Municipal Waste Combustors for Which 

 Construction is Commenced After 

 September 20, 1994 or for Which 

 Modification or Reconstruction is 

 Commenced After June 19, 1996 

 40 CFR part 60, Subpart Ec - Standards of Performance for

 Hospital/Medical/Infectious Waste

 Incinerators for Which Construction is 

 Commenced After June 20, 1996 

 40 CFR part 60, Subpart F - Standards of Performance for Portland

 Cement Plants

 40 CFR part 60, Subpart G - Standards of Performance for Nitric Acid

 Plants

 40 CFR part 60, Subpart H - Standards of Performance for Sulfuric Acid

 Plants

 40 CFR part 60, Subpart I - Standards of Performance for Hot Mix

 Asphalt Facilities

 40 CFR part 60, Subpart J - Standards of Performance for Petroleum

 Refineries

 40 CFR part 60, Subpart K - Standards of Performance for Storage

 Vessels for Petroleum Liquids for Which 

 Construction, Reconstruction, or 

 Modification Commenced After 

 June 11, 1973, and Prior to May 19, 1978 
145

 40 CFR part 60, Subpart Ka - Standards of Performance for Storage

 Vessels for Petroleum Liquids for Which 

 Construction, Reconstruction, or 

 Modification Commenced After

 May 18, 1978, and Prior to July 23, 1984 

 40 CFR part 60, Subpart Kb - Standards of Performance for Volatile

 Organic Liquid Storage Vessels (Including 

 Petroleum Liquid Storage Vessels) for 

 Which Construction, Reconstruction, or 

 Modification Commenced After July 23, 

 1984 

 40 CFR part 60, Subpart L - Standards of Performance for Secondary

 Lead Smelters

 40 CFR part 60, Subpart M - Standards of Performance for Secondary

 Brass and Bronze Production Plants

 40 CFR part 60, Subpart N - Standards of Performance for Primary

 Emissions from Basic Oxygen Process

 Furnaces for Which Construction is 

 Commenced After June 11, 1973 

 40 CFR part 60, Subpart Na - Standards of Performance for Secondary

 Emissions from Basic Oxygen Process

Steelmaking Facilities for Which

 Construction is Commenced After January 

 20, 1983 

 40 CFR part 60, Subpart O - Standards of Performance for Sewage

 Treatment Plants

 40 CFR part 60, Subpart P - Standards of Performance for Primary

 Copper Smelters

 40 CFR part 60, Subpart Q - Standards of Performance for Primary Zinc

 Smelters

 40 CFR part 60, Subpart R - Standards of Performance for Primary Lead

 Smelters

 40 CFR part 60, Subpart S - Standards of Performance for Primary

 Aluminum Reduction Plants 
146

 40 CFR part 60, Subpart T - Standards of Performance for the Phosphate 

 Fertilizer Industry: Wet-Process Phosphoric 

Acid Plants

 40 CFR part 60, Subpart U - Standards of Performance for the Phosphate 

 Fertilizer Industry: Superphosphoric Acid 

 Plants

 40 CFR part 60, Subpart V - Standards of Performance for the Phosphate 

 Fertilizer Industry: Diammonium Phosphate

Plants

 40 CFR part 60, Subpart W - Standards of Performance for the Phosphate 

 Fertilizer Industry: Triple Superphosphate 

 Plants

 40 CFR part 60, Subpart X - Standards of Performance for the Phosphate 

 Fertilizer Industry: Granular Triple 

 Superphosphate Storage Facilities 

 40 CFR part 60, Subpart Y - Standards of Performance for Coal

 Preparation Plants

 40 CFR part 60, Subpart Z - Standards of Performance for Ferroalloy

 Production Facilities

 40 CFR part 60, Subpart AA - Standards of Performance for Steel Plants:

 Electric Arc Furnaces Constructed After

 October 21, 1974 and on or Before August 

 17, 1983 

 40 CFR part 60, Subpart AAa - Standards of Performance for Steel Plants:

 Electric Arc Furnaces and Argon-Oxygen

Decarburization Vessels Constructed After

 August 17, 1983 

 40 CFR part 60, Subpart BB - Standards of Performance for Kraft Pulp

 Mills

 40 CFR part 60, Subpart CC - Standards of Performance for Glass

 Manufacturing Plants

 40 CFR part 60, Subpart DD - Standards of Performance for Grain

 Elevators
147

 40 CFR part 60, Subpart EE - Standards of Performance for Surface

 Coating of Metal Furniture

 40 CFR part 60, Subpart GG - Standards of Performance for Stationary Gas

 Turbines 

 40 CFR part 60, Subpart HH - Standards of Performance for Lime

 Manufacturing Plants

 40 CFR part 60, Subpart KK - Standards of Performance for Lead-Acid

 Battery Manufacturing Plants

 40 CFR part 60, Subpart LL - Standards of Performance for Metallic

 Mineral Processing Plants

 40 CFR part 60, Subpart MM - Standards of Performance for Automobile 

 and Light-Duty Truck Surface Coating 

 Operations 

 40 CFR part 60, Subpart NN - Standards of Performance for Phosphate 

 Rock Plants 

 40 CFR part 60, Subpart PP - Standards of Performance for Ammonium 

 Sulfate Manufacture

 40 CFR part 60, Subpart QQ - Standards of Performance for the Graphic 

 Arts Industry: Publication Rotogravure 

 Printing

 40 CFR part 60, Subpart RR - Standards of Performance for Pressure

 Sensitive Tape and Label Surface Coating

 Operations 

 40 CFR part 60, Subpart SS - Standards of Performance for Industrial 

 Surface Coating: Large Appliances

 40 CFR part 60, Subpart TT - Standards of Performance for Metal Coil

 Surface Coating

 40 CFR part 60, Subpart UU - Standards of Performance for Asphalt

 Processing and Asphalt Roofing

Manufacture

 40 CFR part 60, Subpart VV - Standards of Performance for Equipment 

 Leaks of VOC in the Synthetic Organic 

 Chemicals Manufacturing Industry 
148

 40 CFR part 60, Subpart WW - Standards of Performance for the Beverage

 Can Surface Coating Industry

 40 CFR part 60, Subpart XX - Standards of Performance for Bulk Gasoline 

 Terminals

 40 CFR part 60, Subpart AAA - Standards of Performance for New

 Residential Wood Heaters

 40 CFR part 60, Subpart BBB - Standards of Performance for the Rubber 

 Tire Manufacturing Industry

 40 CFR part 60, Subpart DDD - Standards of Performance for Volatile

 Organic Compound (VOC) Emissions from 

 the Polymer Manufacturing Industry 

 40 CFR part 60, Subpart FFF - Standards of Performance for Flexible Vinyl

 and Urethane Coating and Printing

 40 CFR part 60, Subpart GGG - Standards of Performance for Equipment 

 Leaks of VOC in Petroleum Refineries

 40 CFR part 60, Subpart HHH - Standards of Performance for Synthetic 

 Fiber Production Facilities

 40 CFR part 60, Subpart III - Standards of Performance for Volatile

 Organic Compound (VOC) Emissions From 

 the Synthetic Organic Chemical

 Manufacturing Industry (SOCMI) Air 

 Oxidation Unit Processes

 40 CFR part 60, Subpart JJJ - Standards of Performance for Petroleum Dry

 Cleaners

 40 CFR part 60, Subpart KKK - Standards of Performance for Equipment 

 Leaks of VOC From Onshore Natural Gas 

 Processing Plants

 40 CFR part 60, Subpart LLL - Standards of Performance for Onshore 

 Natural Gas Processing: SO2 Emissions

 40 CFR part 60, Subpart NNN - Standards of Performance for Volatile

 Organic Compound (VOC) Emissions From 

 Synthetic Organic Chemical Manufacturing

 Industry (SOCMI) Distillation Operations
149

 40 CFR part 60, Subpart OOO - Standards of Performance for Nonmetallic 

 Mineral Processing Plants

 40 CFR part 60, Subpart PPP - Standards of Performance for Wool 

 Fiberglass Insulation Manufacturing Plants 

 40 CFR part 60, Subpart QQQ - Standards of Performance for VOC

 Emissions From Petroleum Refinery

Wastewater Systems

 40 CFR part 60, Subpart RRR - Standards of Performance for Volatile

 Organic Compound Emissions from 

 Synthetic Organic Chemical Manufacturing

 Industry (SOCMI) Reactor Processes

 40 CFR part 60, Subpart SSS - Standards of Performance for Magnetic

 Tape Coating Facilities

 40 CFR part 60, Subpart TTT - Standards of Performance for Industrial 

 Surface Coating: Surface Coating of Plastic

 Parts for Business Machines

 40 CFR part 60, Subpart UUU - Standards of Performance for Calciners and

 Dryers in Mineral Industries 

 40 CFR part 60, Subpart VVV - Standards of Performance for Polymeric

 Coating of Supporting Substrates Facilities 

 40 CFR part 60, Subpart WWW - Standards of Performance for Municipal 

 Solid Waste Landfills

 40 CFR part 60, Subpart AAAA - Standards of Performance for Small

 Municipal Waste Combustion Units for 

 Which Construction is Commenced After 

 August 30, 1999 or for Which Modification 

 or Reconstruction is Commenced After June 

 6, 2001 

 40 CFR part 60, Subpart CCCC - Standards of Performance for Commercial

 and Industrial Solid Waste Incineration 

 Units for Which Construction is 

 Commenced After November 30, 1999 or 

 for Which Modification or Reconstruction 

 is Commenced on or After June 1, 2001 
150

 40 CFR part 60, Subpart EEEE - Standards of Performance for Other Solid Waste 

 Incineration Units for Which Construction is 

 Commenced After December 9, 2004, or for Which 

 Modification or Reconstruction is Commenced on 

 or After June 16, 2006 

8.2.1.4 MACT - HAPs Program

The Air Quality Division annually incorporates by reference the Federal National Emission 

Standards for Hazardous Air Pollutants (NESHAPs). To the extent that NESHAPs regulate 

visibility impairing pollutants through surrogates, these programs may prove helpful in reducing 

visibility impairment. These standards are incorporated via the Wyoming Air Quality Standards 

and Regulations, Chapter 5, Section 3. Section 3 first became an effective State rule in August 

of 1997, with the latest revision becoming effective in May 2008. The delegation request for 

Section 3 was submitted to the EPA in June of 2008. The list of NESHAP (MACT) standards 

incorporated by reference include: 

 40 CFR part 63, Subpart D - Regulations Governing Compliance 

 Extensions for Early Reductions of 

 Hazardous Air Pollutants 

 40 CFR part 63, Subpart F - National Emission Standards for 

 Organic Hazardous Air Pollutants 

 From the Synthetic Organic 

 Chemical Manufacturing Industry 

 40 CFR part 63, Subpart G - National Emission Standards for 

 Organic Hazardous Air Pollutants

 From the Synthetic Organic 

 Chemical Manufacturing Industry 

 for Process Vents, Storage Vessels,

Transfer Operations, and Wastewater

 40 CFR part 63, Subpart H - National Emission Standards for 

 Organic Hazardous Air Pollutants 

 for Equipment Leaks 

 40 CFR part 63, Subpart I - National Emission Standards for 

 Organic Hazardous Air Pollutants 

 for Certain Processes Subject to

 the Negotiated Regulation for

Equipment Leaks
151

 40 CFR part 63, Subpart J - National Emission Standards for 

 Hazardous Air Pollutants for 

 Polyvinyl Chloride and Copolymers 

 Production 

 40 CFR part 63, Subpart L - National Emission Standards for 

 Coke Oven Batteries

 40 CFR part 63, Subpart M - National Perchloroethylene Air

 Emission Standards for Dry 

 Cleaning Facilities

 40 CFR part 63, Subpart N - National Emission Standards for 

 Chromium Emissions From Hard

and Decorative Chromium

Electroplating and Chromium 

 Anodizing Tanks 

 40 CFR part 63, Subpart O - Ethylene Oxide Emissions

 Standards for Sterilization

Facilities

 40 CFR part 63, Subpart Q - National Emission Standards for 

 Hazardous Air Pollutants for 

 Industrial Process Cooling 

 Towers

 40 CFR part 63, Subpart R - National Emission Standards for 

 Gasoline Distribution Facilities

 (Bulk Gasoline Terminals and 

 Pipeline Breakout Stations) 

 40 CFR part 63, Subpart S - National Emission Standards for 

 Hazardous Air Pollutants from the 

 Pulp and Paper Industry 

 40 CFR part 63, Subpart T - National Emission Standards for 

 Halogenated Solvent Cleaning 

 40 CFR part 63, Subpart U - National Emission Standards for 

 Hazardous Air Pollutant Emissions: 

 Group I Polymers and Resins 
152

 40 CFR part 63, Subpart W - National Emission Standards for 

 Hazardous Air Pollutants for 

 Epoxy Resins Production 

 and Non-Nylon Polyamides 

 Production 

 40 CFR part 63, Subpart X - National Emission Standards for 

 Hazardous Air Pollutants from 

 Secondary Lead Smelting

 40 CFR part 63, Subpart Y - National Emission Standards for 

 Marine Tank Vessel Loading

 Operations 

 40 CFR part 63, Subpart AA - National Emission Standards for 

 Hazardous Air Pollutants From 

 Phosphoric Acid Manufacturing 

 Plants

 40 CFR part 63, Subpart BB - National Emission Standards for 

 Hazardous Air Pollutants From 

 Phosphate Fertilizers Production 

 Plants

 40 CFR part 63, Subpart CC - National Emission Standards for 

 Hazardous Air Pollutants From 

 Petroleum Refineries

 40 CFR part 63, Subpart DD - National Emission Standards for 

 Hazardous Air Pollutants from 

 Off-Site Waste and Recovery

 Operations 

 40 CFR part 63, Subpart EE - National Emission Standards for 

 Magnetic Tape Manufacturing

 Operations 

 40 CFR part 63, Subpart GG - National Emission Standards for 

 Aerospace Manufacturing and

 Rework Facilities

 40 CFR part 63, Subpart HH - National Emission Standards for 

 Hazardous Air Pollutants From 

 Oil and Natural Gas Production 

 Facilities
153

 40 CFR part 63, Subpart II - National Emission Standards for 

 Shipbuilding and Ship Repair 

 (Surface Coating) 

 40 CFR part 63, Subpart JJ - National Emission Standards for 

 Wood Furniture Manufacturing 

 Operations 

 40 CFR part 63, Subpart KK - National Emission Standards for 

 the Printing and Publishing Industry 

 40 CFR part 63, Subpart LL - National Emission Standards for 

 Hazardous Air Pollutants for 

 Primary Aluminum Reduction Plants

 40 CFR part 63, Subpart MM - National Emission Standards for 

 Hazardous Air Pollutants for 

 Chemical Recovery Combustion 

 Sources at Kraft, Soda, Sulfite, 

 and Stand-Alone Semichemical

 Pulp Mills

 40 CFR part 63, Subpart OO - National Emission Standards for 

 Tanks - Level 1

 40 CFR part 63, Subpart PP - National Emission Standards for 

 Containers 

 40 CFR part 63, Subpart QQ - National Emission Standards for 

 Surface Impoundments

 40 CFR part 63, Subpart RR - National Emission Standards for

 Individual Drain Systems 

 40 CFR part 63, Subpart SS - National Emission Standards for 

 Closed Vent Systems, Control 

 Devices, Recovery Devices and

 Routing to a Fuel Gas System 

 or a Process

 40 CFR part 63, Subpart TT - National Emission Standards for 

 Equipment Leaks - Control Level 1 

 40 CFR part 63, Subpart UU - National Emission Standards for 

 Equipment Leaks - Control Level

 2 Standards 
154

 40 CFR part 63, Subpart VV - National Emission Standards for 

 Oil-Water Separators and OrganicWater Separators

 40 CFR part 63, Subpart WW - National Emission Standards for 

 Storage Vessels (Tanks) - Control 

Level 2

 40 CFR part 63, Subpart XX - National Emission Standards for

 Ethylene Manufacturing Process

Units: Heat Exchange Systems

 and Waste Operations

 40 CFR part 63, Subpart YY - National Emission Standards for 

 Hazardous Air Pollutants for 

 Source Categories: Generic

Maximum Achievable Control 

 Technology Standards 

 40 CFR part 63, Subpart CCC - National Emission Standards for 

 Hazardous Air Pollutants for Steel 

 Pickling - HCl Process Facilities

 and Hydrochloric Acid 

 Regeneration Plants

 40 CFR part 63, Subpart DDD - National Emission Standards for 

 Hazardous Air Pollutants for 

 Mineral Wool Production 

 40 CFR part 63, Subpart EEE - National Emission Standards for 

 Hazardous Air Pollutants from 

 Hazardous Waste Combustors 

 40 CFR part 63, Subpart GGG - National Emission Standards for 

 Pharmaceuticals Production

 40 CFR part 63, Subpart HHH - National Emission Standards for 

 Hazardous Air Pollutants From 

 Natural Gas Transmission and

 Storage Facilities

 40 CFR part 63, Subpart III - National Emission Standards for 

 Hazardous Air Pollutants for 

 Flexible Polyurethane Foam

 Production 
155

 40 CFR part 63, Subpart JJJ - National Emission Standards for 

 Hazardous Air Pollutant Emissions:

 Group IV Polymers and Resins 

 40 CFR part 63, Subpart LLL - National Emission Standards for 

 Hazardous Air Pollutants From the 

 Portland Cement Manufacturing 

 Industry 

 40 CFR part 63, Subpart MMM - National Emission Standards for 

 Hazardous Air Pollutants for 

 Pesticide Active Ingredient

 Production 

 40 CFR part 63, Subpart NNN - National Emission Standards for 

 Hazardous Air Pollutants for Wool 

 Fiberglass Manufacturing

 40 CFR part 63, Subpart OOO - National Emission Standards for 

 Hazardous Air Pollutant Emissions: 

 Manufacture of Amino/Phenolic 

 Resins

 40 CFR part 63, Subpart PPP - National Emission Standards for 

 Hazardous Air Pollutants for 

 Polyether Polyols Production 

 40 CFR part 63, Subpart QQQ - National Emission Standards for 

 Hazardous Air Pollutants for 

 Primary Copper Smelting

 40 CFR part 63, Subpart RRR - National Emission Standards for 

 Hazardous Air Pollutants for

 Secondary Aluminum Production 

 40 CFR part 63, Subpart TTT - National Emission Standards for 

 Hazardous Air Pollutants for 

 Primary Lead Smelting

 40 CFR part 63, Subpart UUU - National Emission Standards for 

 Hazardous Air Pollutants for 

Petroleum Refineries: Catalytic

Cracking Units, Catalytic

 Reforming Units, and Sulfur 

 Recovery Units
156

 40 CFR part 63, Subpart VVV - National Emission Standards for 

 Hazardous Air Pollutants: Publicly

 Owned Treatment Works 

 40 CFR part 63, Subpart XXX - National Emission Standards for 

 Hazardous Air Pollutants for 

 Ferroalloys Production: 

 Ferromanganese and

Silicomanganese

 40 CFR part 63, Subpart AAAA - National Emission Standards for 

 Hazardous Air Pollutants: 

 Municipal Solid Waste Landfills

 40 CFR part 63, Subpart CCCC - National Emission Standards for 

 Hazardous Air Pollutants: 

 Manufacturing of Nutritional Yeast

 40 CFR part 63, Subpart DDDD - National Emission Standards for 

 Hazardous Air Pollutants: Plywood 

 and Composite Wood Products 

 40 CFR part 63, Subpart EEEE - National Emission Standards for 

 Hazardous Air Pollutants: Organic 

 Liquids Distribution (Non-Gasoline)

 40 CFR part 63, Subpart FFFF - National Emission Standards for 

 Hazardous Air Pollutants: 

 Miscellaneous Organic Chemical

Manufacturing

 40 CFR part 63, Subpart GGGG - National Emission Standards for 

 Hazardous Air Pollutants: Solvent 

Extraction for Vegetable Oil

 Production 

 40 CFR part 63, Subpart HHHH - National Emission Standards for 

 Hazardous Air Pollutants for Wet- 

 Formed Fiberglass Mat Production 

 40 CFR part 63, Subpart IIII - National Emission Standards for 

 Hazardous Air Pollutants: Surface 

 Coating of Automobiles and Light- 

 Duty Trucks 
157

 40 CFR part 63, Subpart JJJJ - National Emission Standards for 

 Hazardous Air Pollutants: Paper 

 and Other Web Coating 

 40 CFR part 63, Subpart KKKK - National Emission Standards for 

 Hazardous Air Pollutants: Surface 

 Coating of Metal Cans

 40 CFR part 63, Subpart MMMM - National Emission Standards for 

 Hazardous Air Pollutants for Surface

 Coating of Miscellaneous Metal

 Parts and Products 

 40 CFR part 63, Subpart NNNN - National Emission Standards for 

 Hazardous Air Pollutants: 

 Surface Coating of Large

 Appliances

 40 CFR part 63, Subpart OOOO - National Emission Standards for 

 Hazardous Air Pollutants: 

 Printing, Coating, and Dyeing of 

 Fabrics and Other Textiles

 40 CFR part 63, Subpart PPPP - National Emission Standards for 

 Hazardous Air Pollutants for Surface 

 Coating of Plastic Parts and Products 

 40 CFR part 63, Subpart QQQQ - National Emission Standards for 

 Hazardous Air Pollutants: Surface 

 Coating of Wood Building Products 

 40 CFR part 63, Subpart RRRR - National Emission Standards for

 Hazardous Air Pollutants: Surface 

 Coating of Metal Furniture

 40 CFR part 63, Subpart SSSS - National Emission Standards for 

 Hazardous Air Pollutants: Surface 

 Coating of Metal Coil

 40 CFR part 63, Subpart TTTT - National Emission Standards for 

 Hazardous Air Pollutants for Leather 

 Finishing Operations 

 40 CFR part 63, Subpart UUUU - National Emission Standards for 

 Hazardous Air Pollutants for 

 Cellulose Products Manufacturing 
158

 40 CFR part 63, Subpart VVVV - National Emission Standards for 

 Hazardous Air Pollutants for Boat 

 Manufacturing

 40 CFR part 63, Subpart WWWW - National Emissions Standards for 

 Hazardous Air Pollutants: 

 Reinforced Plastic Composites

 Production 

 40 CFR part 63, Subpart XXXX - National Emission Standards for 

 Hazardous Air Pollutants: Rubber 

 Tire Manufacturing

 40 CFR part 63, Subpart YYYY - National Emission Standards for 

 Hazardous Air Pollutants for 

 Stationary Combustion Turbines 

 40 CFR part 63, Subpart ZZZZ - National Emission Standards for 

 Hazardous Air Pollutants for 

 Stationary Reciprocating Internal

 Combustion Engines 

 40 CFR part 63, Subpart AAAAA - National Emissions Standards for 

 Hazardous Air Pollutants for Lime 

 Manufacturing Plants

 40 CFR part 63, Subpart BBBBB - National Emission Standards for 

 Hazardous Air Pollutants for 

 Semiconductor Manufacturing 

 40 CFR part 63, Subpart CCCCC - National Emission Standards for 

 Hazardous Air Pollutants for Coke 

 Ovens: Pushing, Quenching, and 

 Battery Stacks

 40 CFR part 63, Subpart DDDDD - National Emission Standards for 

 Hazardous Air Pollutants for 

 Industrial, Commercial, and

 Institutional Boilers and Process

 Heaters

 40 CFR part 63, Subpart EEEEE - National Emission Standards for 

 Hazardous Air Pollutants for Iron 

 and Steel Foundries 
159

 40 CFR part 63, Subpart FFFFF - National Emission Standards for 

 Hazardous Air Pollutants for 

 Integrated Iron and Steel 

 Manufacturing Facilities

 40 CFR part 63, Subpart GGGGG - National Emission Standards for 

 Hazardous Air Pollutants: Site

 Remediation

 40 CFR part 63, Subpart HHHHH - National Emission Standards for 

 Hazardous Air Pollutants: 

 Miscellaneous Coating

Manufacturing

 40 CFR part 63, Subpart IIIII - National Emission Standards for 

 Hazardous Air Pollutants: Mercury 

 Emissions From Mercury Cell 

 Chlor-Alkali Plants

 40 CFR part 63, Subpart JJJJJ - National Emission Standards for 

 Hazardous Air Pollutants for Brick 

 and Structural Clay Products 

 Manufacturing

 40 CFR part 63, Subpart KKKKK - National Emission Standards for 

 Hazardous Air Pollutants for Clay 

 Ceramics Manufacturing

 40 CFR part 63, Subpart LLLLL - National Emission Standards for 

 Hazardous Air Pollutants: Asphalt 

 Processing and Asphalt Roofing

Manufacturing

 40 CFR part 63, Subpart MMMMM - National Emission Standards for 

 Hazardous Air Pollutants: Flexible

Polyurethane Foam Fabrication

 Operations 

 40 CFR part 63, Subpart NNNNN - National Emission Standards for 

 Hazardous Air Pollutants:

 Hydrochloric Acid Production 

 40 CFR part 63, Subpart PPPPP - National Emission Standards for 

 Hazardous Air Pollutants for 

 Engine Test Cells/Stands
160

 40 CFR part 63, Subpart QQQQQ - National Emission Standards for 

 Hazardous Air Pollutants for 

 Friction Materials Manufacturing

Facilities

 40 CFR part 63, Subpart RRRRR - National Emission Standards for 

 Hazardous Air Pollutants: Taconite 

 Iron Ore Processing

 40 CFR part 63, Subpart SSSSS - National Emission Standards for 

 Hazardous Air Pollutants for 

 Refractory Products Manufacturing

 40 CFR part 63, Subpart TTTTT - National Emissions Standards for 

 Hazardous Air Pollutants for Primary 

 Magnesium Refining

The Air Quality Division also determines case-by-case MACT determinations through Chapter 

6, Section 6. 

8.2.1.5 Phase I Visibility Rules - Wyoming Reasonably Attributable Visibility Impairment

 Rules

In response to EPA’s Phase I visibility rules, Wyoming adopted the Wyoming State 

Implementation Plan for Class I Visibility Protection, effective May 10, 1988. It was approved 

by the U.S. EPA by notice in the Federal Register on February 15, 1989, under 40 CFR part 52, 

and became effective on April 17, 1989. This visibility rule contains short and long-term 

strategies for making reasonable progress toward the national goal, related to addressing 

reasonably attributable impairment in the State’s Class I areas through visibility monitoring and 

control strategies. This rule incorporates PSD requirements for visibility protection from new or 

modified major stationary sources, and if necessary applying BART to existing stationary 

sources if certified as causing reasonably attributable visibility impairment.

8.2.1.6 Ongoing Implementation of Federal Mobile Source Regulations 

The Federal Motor Vehicle Control Program (FMVCP) has produced and is continuing to 

produce large reductions in motor vehicle emissions of NOx, PM, and VOCs. Beginning in 

2006, EPA mandated new standards for on-road (highway) diesel fuel, known as ultra-low sulfur 

diesel (ULSD). This regulation dropped the sulfur content of diesel fuel from 500 ppm to 15 

ppm. ULSD fuel enables the use of cleaner technology diesel engines and vehicles with 

advanced emissions control devices, resulting in significantly lower emissions. Diesel fuel 

intended for locomotive, marine and non-road (farming and construction) engines and equipment 

was required to meet the low sulfur diesel fuel maximum specification of 500 ppm sulfur in 2007 

(down from 5,000 ppm). By 2010, the ULSD fuel standard of 15-ppm sulfur will apply to all 

non-road diesel fuel. Locomotive and marine diesel fuel will be required to meet the ULSD 
161

standard beginning in 2012, resulting in further reductions of diesel emissions. These rules not 

only reduce SO2 emissions, but also NOx and PM emissions. 

In addition to the ULSD standard, listed below are several other significant Federal programs:

Federal On-Road Measures

● Tier 2 vehicle emission standards and Federal low-sulfur gasoline

● National low emissions vehicle standards (NLEV) 

● Heavy-duty diesel standards 

Federal Non-Road Measures

● Lawn and garden equipment

● Tier 2 heavy-duty diesel equipment 

● Locomotive engine standards 

● Compression ignition standards for vehicles and equipment 

● Recreational marine engine standards

In addition, the Renewable Fuel Standard Under Section 211(o) of the Clean Air Act as Amended 

by the Energy Policy Act of 2005, is determined annually (must be published in the Federal 

Register by November 30 of each year) by EPA and is applicable to refiners, importers and 

blenders of gasoline. 

8.2.1.7 Ongoing Implementation of Programs to Meet PM10 NAAQS

Currently, only one community in Wyoming, Sheridan, is designated as a nonattainment area 

under the PM10 National Ambient Air Quality Standard (NAAQS). The significance of this 

nonattainment area in terms of regional haze is that significant reductions in PM10 emissions 

have been made in the last ten years, by adopting strategies to address the primary emission 

sources in the community. The major contributing sources causing nonattainment in this 

community are road dust, residential woodstoves, outdoor burning, and to a lesser degree, 

industry. 

8.2.1.7.1 Nonattainment SIP (PM10) - City of Sheridan 

Because Sheridan, Wyoming was designated a Group I area under the PM10 Regulations 

promulgated by the EPA on July 20, 1987, the Air Quality Division was required to develop a 

State Implementation Plan outlining control strategies with a demonstration of attainment and 

maintenance of the standards. In cooperation with the Sheridan City government, a plan was 

developed which addressed four PM10 control measures.

The first control measure involved implementing a sanding plan or air quality maintenance plan 

(AQMP), which aimed to reduce PM10 emissions by designating specific limitations/guidelines 

for sanding routes, sanding mediums, application rates, and street cleaning. 

The second control measure was a voluntary curtailment of solid fuels combustion, whereby an 

ordinance was enacted allowing the designation of voluntary “no burn days” when PM10
162

concentrations exceed or are predicted to exceed established criteria levels. The Division 

collects “real time” particulate data and uses the information in conjunction with weather 

predictions to trigger requests for burning curtailment. 

Fugitive dust concerns comprised the third control measure. Several industrial areas in the City 

of Sheridan were identified as significant sources of fugitive dust. The Division required that 

these facilities submit a dust control plan specifying as a minimum, application of asphalt, oil, or 

suitable chemical dust control agents on unpaved roads within their operations. One facility was 

asked to use more durable washed sand rather than scoria for skid control. 

Because some of the streets of Sheridan are maintained by the County and the Highway 

Department, as a fourth control measure these agencies were also contacted by the Division in an 

effort to implement similar sanding practices in the City. Sanding plans were submitted by both 

the County and Highway Department specifying sanding mediums, routes, and application rates. 

8.2.1.7.2 Natural and Uncontrollable Sources Program - Natural Events Action Plan

On May 30, 1996, the Environmental Protection Agency (EPA) issued a Natural Events Policy 

(NEP) which recognized that certain uncontrollable natural events, such as high winds, wildland 

fires, and volcanic/seismic activity can result in adverse consequences for the National Ambient 

Air Quality Standard (NAAQS). The NEP set forth procedures for protecting public health 

through the development of a Natural Events Action Plan (NEAP) which implements Best 

Available Control Measures (BACM) for human-generated particulate emissions in areas where 

the PM10 (particulate matter having a nominal aerodynamic equal to or less than 10 microns) 

standard may be violated due to these uncontrolled natural events. The NEP also provides that if 

an approved NEAP is implemented, future air quality exceedances due to uncontrollable natural 

events may be flagged, and, if demonstrated to be a natural event, not be considered when 

determining the region’s air quality designation if BACM measures are being implemented.

A number of Federal Reference or Equivalent PM10 monitors are located in Wyoming’s Powder 

River Basin (PRB) at several large mining operations. Some of the monitors have recorded 

exceedances of the 24-hour NAAQS for PM10. Each of the monitored exceedances was 

associated with high winds and blowing dust resulting from prolonged periods of low 

precipitation and consequential low soil moisture content. 

Recognizing the need to protect public health in the Powder River Basin where measured PM10

values exceeded the NAAQS because of wind generated dust, in early 2007 the State of 

Wyoming, with the aid of stakeholders, prepared a Natural Events Action Plan based on EPA 

Natural Event Policy (NEP) guidance. This plan outlines specific procedures to be taken in 

response to future high wind events. In short, the purpose of the plan is to: 

● Educate the public about the problem; 

● Mitigate health impacts on exposed populations during future events; and 

● Identify and implement Best Available Control Measures (BACM) for significant, 

anthropogenic sources of windblown dust. 
163

All coal mines in the Wyoming PRB employ Best Available Control Technology (BACT). This 

Natural Events Action Plan for the Powder River Basin identifies BACT measures in place as the 

result of existing permit requirements, additional potential control measures identified as BACM, 

and reactionary control measures directed at transient problem sites that may be implemented 

during Natural Events. Implementation of BACT, BACM, and reactionary control measures will 

assure that anthropogenic dust emissions from the coal mines in the PRB are controlled to the 

greatest extent possible. The goal is to protect public health and to minimize exceedances of the 

PM10 NAAQS through the continued implementation of BACT, and implementation of BACM 

and reactionary control measures.

The Natural Events Action Plan may be accessed at: http://deq.state.wy.us/aqd/NEAP.asp. 

8.2.2 Measures to Mitigate the Impacts of Construction Activities

Chapter 3 of the Wyoming Air Quality Standards and Regulations (WAQSR) establishes limits 

on the quantity, rate, or concentration of emissions of air pollutants, including any requirements 

which limit the level of opacity, prescribe equipment, set fuel specifications, or prescribe 

operation or maintenance procedures. Specifically, Chapter 3, Section 2(f), prescribes measures 

to ensure the control of fugitive dust emissions during construction or demolition activities, 

handling, storage and transporting of materials and agricultural practices. Chapter 3, Section 2(f) 

was originally adopted by the State of Wyoming on February 22, 1972. The entire section was 

restructured on October 29, 1999. Section 2(f) was revised on March 30, 2000 and submitted to 

EPA on August 13, 2001, then resubmitted on September 12, 2003 as part of the restructuring of 

the rules. Revisions to Chapter 3 were most recently approved by EPA on July 28, 2004. The 

State believes these regulations address common construction activities. 

Wyoming believes point and area sources of emissions from these regulated sources are in part 

attributed to impacting regional haze in Wyoming. Wyoming relies on the particulate emission 

control measures specified in Chapter 3 to most directly address these sources of fine and coarse 

particles known to have a minor, but measured, impact on visibility in Class I areas of the state.

8.2.3 Emission Limitations and Schedules of Compliance

The implementation of BART, as described in Chapter 6, will contain emission limits and 

schedules of compliance for those sources either installing BART controls or taking Federally 

enforceable permit limitations. The four-factor analysis identifies some additional measures that 

are appropriate for this first Regional Haze Plan. The evaluation of non-BART sources as part of 

the LTS identifies additional emission reductions and improves visibility by 2018. 

8.2.4 Source Retirement and Replacement Schedules

Part of this LTS contains an evaluation of non-BART sources, described in Sections 8.3.4 and 

8.3.5. The Division is not currently aware of any specific scheduled shutdowns, retirements in 

upcoming years, or replacement schedules, such as planned installation of new control 

equipment to meet other regulations or routine equipment replacement or modernization. As the 

Division becomes aware of such actions, they will be factored into upcoming reviews. 
164

8.2.5 Agricultural and Forestry Smoke Management Techniques

Wyoming Air Quality Standards and Regulations (WAQSR) Chapter 10, Smoke Management, 

was originally adopted by the State of Wyoming on February 10, 1970. Chapter 10 has been 

revised several times, most recently becoming an effective State rule on April 5, 2005. Chapter 

10 was submitted to EPA on April 23, 2004 and is awaiting EPA approval. A smoke 

management certification was submitted to EPA on November 17, 2005. The last EPA approval 

was part of the entire restructuring of the rules, approved on July 28, 2004. Chapter 10 is 

utilized in Wyoming to establish restrictions and requirements on specific burning practices. 

Section 2 regulates refuse burning; open burning of trade wastes, for salvage operations, for fire 

hazards, and for firefighting training; and vegetative material open burning. Section 2 includes 

the permitting of prescribed fires occurring on Federal and State lands, and requires Federal land 

and State land managers to perform modeling to determine meteorological conditions under 

which burning can occur and maintain compliance with ambient air quality standards. Section 3 

specifically regulates emissions from wood waste burners. Section 4 regulates sources of 

vegetative burning for the management of air quality emissions and impacts from smoke on 

public health and visibility. 

 

A Smoke Management Program Guidance Document was developed in November 2004, to 

assist burners in understanding the requirements and aid in the implementation of Section 4. The 

intent of Chapter 10 is to provide an equitable and workable program for all burners that is 

simple to implement and is the least burdensome possible, thereby focusing on the most common 

situations rather than extreme or isolated circumstances. Burners must comply with all local 

(city and county), State and Federal laws, regulations and ordinances relating to burning in 

addition to complying with the regulatory requirements for air quality. 

Division staff actively participate in the WRAP Fire Emissions Joint Forum (FEJF), formed to 

address both policy and technical issues concerning smoke effects that are caused by wildland 

and agricultural fires on public, tribal, and private lands. The FEJF is guided by the 

recommendations contained in the GCVTC Final Report and the requirements of the Regional 

Haze Rule regarding fire emissions and visibility. The FEJF has developed several policies for 

the WRAP through a stakeholder-based consensus process to assist the WRAP states and tribes 

in addressing emissions from fire sources. In these policies, the WRAP seeks to provide a 

consistent framework that states and tribes can use to efficiently develop their individual regional 

haze implementation plans, long-term strategies, and periodic progress reports. 

The WRAP has advanced the following policies developed by the FEJF as viable tools for both 

Section 308 and 309 states to meet the requirements of the Rule. 

● The WRAP Policy for Categorizing Fire Emissions6 was developed to clarify the 

complex relationship between what is considered a natural source of fire and what is 

considered a human-caused source, as acknowledged in the Rule. A methodology to 

categorize fire emissions as either “natural” or “anthropogenic” is the basis of the Policy; 

 

6 Western Regional Air Partnership, Fire Emissions Joint Forum, Natural Background Task Team, Policy for 

Categorizing Fire Emissions, November 15, 2001.
165

thus providing the foundation for fire’s inclusion in natural background condition values 

and ultimately, the tracking of reasonable progress. 

● The WRAP Policy on Enhanced Smoke Management Programs for Visibility7 defines the 

enhanced smoke management program as smoke management efforts that specifically 

address visibility, thereby, going beyond the EPA Interim Policy and the AAQTF Air 

Quality Policy specific guidance provided for smoke management programs that address 

public health and nuisance concerns. The Policy identifies for states/tribes in the WRAP 

region the elements of an enhanced smoke management program to address visibility 

effects from all types of fire that contribute to visibility impairment in mandatory Federal 

Class I areas.

● The WRAP defines the annual emission goal as a quantifiable value that is used to 

measure progress each year toward the desired outcome of achieving the minimum 

emission increase from fire. In the WRAP Policy on Annual Emissions Goals for Fire8, 

the WRAP outlines a process by which states/tribes may establish annual emission goals, 

based on the utilization of currently available emission reduction techniques, to include in 

their Regional Haze SIPs.

● It is the position of the WRAP Policy on Fire Tracking Systems9 that it is necessary to 

track fire activity information in the WRAP region using a fire tracking system, which 

will also provide the information essential to create a fire emissions inventory. The 

Policy identifies seven essential components of a fire tracking system that represent the 

minimum spatial and temporal fire activity information necessary to consistently 

calculate emissions and to meet the requirements of the Rule.

The Air Quality Division is required to conduct an Annual Program Evaluation to assess the 

adequacy of the design, impact and implementation of Wyoming’s Smoke Management 

Program. The first Evaluation covered the program implementation during calendar years 2005 

and 2006. 

8.2.6 Enforceability of Wyoming’s Measures

Section 51.308(d)(3)(v)(F) of the Regional Haze Rule requires states to ensure that emission 

limitations and control measures used to meet reasonable progress goals are enforceable. 

Wyoming has ensured that all existing emission limitations and control measures, for which the 

State of Wyoming is responsible, used to meet reasonable progress goals are enforceable at the 

State level through the Wyoming Air Quality Standards and Regulations (WAQSR) or Stateissued permits. Many of the actions included in the SIP are already federally enforceable. 

 

7 Western Regional Air Partnership, Fire Emissions Joint Forum, Enhanced Smoke Management Task Team, WRAP 

Policy on Enhanced Smoke Management Programs for Visibility, November 12, 2002.

8 Western Regional Air Partnership, Fire Emissions Joint Forum, Annual Emission Goals Task Team, WRAP Policy 

on Annual Emission Goals for Fire, DRAFT December 16, 2002.

9 Western Regional Air Partnership, Fire Emissions Joint Forum, WRAP Policy on Fire Tracking Systems, DRAFT 

December 19, 2002.
166

However, BART permit conditions and long-term strategy commitments for the Laramie River 

Station and the Jim Bridger Power Plant are currently only enforceable at the State level. Once 

EPA approves this SIP, these measures will be federally enforceable. The BART determinations 

are summarized in Table 6.4-1 and the long-term strategy commitments can be found in Section 

8.3.3. 

8.3 Additional Measures in the Long-Term Strategy

This section of the LTS identifies new measures being proposed by the Division for achieving 

reasonable progress. These reasonable progress measures will be evaluated and discussed in the 

next Plan update in 2013. 

8.3.1 Future Federal Mobile Programs

A new rule, “Control of Emissions of Air Pollution from Locomotives and Marine CompressionIgnition Engines Less Than 30 Liters per Cylinder”, was signed on March 14, 2008. EPA 

estimates that by 2030, this program will reduce annual emissions of NOx by about 800,000 tons 

and PM emissions by 27,000 tons. Emission reductions are expected to continue as fleet 

turnover is completed. These standards are intended to achieve these large reductions in 

emissions through the use of technologies such as in-cylinder controls, aftertreatment, and low 

sulfur fuel, perhaps as early as 2011. 

In June 2009, EPA announced a rule (Control of Emissions from New Marine CompressionIgnition Engines at or Above 30 Liters per Cylinder) proposing more stringent exhaust emission 

standards for the largest marine diesel engines used for propulsion on oceangoing vessels (called 

Category 3 engines). The proposed engine standards are equivalent to the nitrogen oxides limits 

recently adopted in amendments to Annex VI to the International Convention for the Prevention 

of Pollution from Ships (MARPOL). The near-term standards for newly-built engines would 

apply beginning in 2011. Long-term standards would begin in 2016, and are based on the 

application of high-efficiency aftertreatment technology. By 2030, this strategy to address 

emissions from oceangoing vessels is expected to reduce annual emissions of NOx in the U.S. by 

approximately 1.2 million tons and particulate matter emissions by about 143,000 tons. When 

fully implemented, the coordinated strategy is anticipated to reduce NOx emissions by 80 percent 

and PM emissions by 85 percent, compared to the current limits applicable to these engines. 

A proposed rule, the Renewable Fuel Standard (RFS2), was signed by Administrator Jackson on 

May 5, 2009. EPA is proposing that this rule take effect on January 1, 2010; however, this date 

is tentative and it could be mid-2010 or January 1, 2011 before this rule becomes final. This rule 

intends to address changes to the Renewable Fuel Standard program as required by the Energy 

Independence and Security Act of 2007 (EISA). The revised statutory requirements establish 

new specific volume standards for cellulosic biofuel, biomass-based diesel, advanced biofuel, 

and total renewable fuel that must be used in transportation fuel each year. The revised statutory 

requirements also include new definitions and criteria for both renewable fuels and the 

feedstocks used to produce them, including new greenhouse gas emission (GHG) thresholds for 

renewable fuels. The regulatory requirements for RFS will apply to domestic and foreign 

producers and importers of renewable fuel. It is estimated that annual GHG emissions from 
167

transportation will be reduced by approximately 160 million tons, the equivalent of the removal 

of 24 million vehicles from the highways. In addition, 36 billion gallons of renewable fuel will 

displace approximately 11% of gasoline and diesel consumption in 2022. The majority of the 

reductions are expected to come from reduced petroleum imports. 

8.3.2 Efforts to Address Offshore Shipping

As depicted by PSAT results in Chapter 5, offshore marine vessel emissions contribute to 

Wyoming Class I areas. Wyoming has no authority to regulate offshore shipping emissions and 

must rely upon other states such as California for adoption of regulations. On February 28, 2003 

EPA adopted emission standards for new marine diesel engines installed on vessels flagged or 

registered in the United States with displacement at or above 30 liters per cylinder. Also adopted 

in this rulemaking were additional standards for new engines with displacement at or above 2.5 

liters per cylinder but less than 30 liters per cylinder. This rule established a deadline of April 27, 

2007 for EPA to promulgate a second set of emission standards for these engines. Because much 

of the information necessary to develop more stringent Category 3 marine diesel engines 

standards has become available only recently, a new deadline for the rulemaking to consider the 

next tier of Category 3 marine diesel engine standards has been set for December 17, 2009. On 

December 7, 2007, EPA announced an advance notice of proposed rulemaking regarding the 

above-referenced standards, first set in 2003. The advanced notice of proposed rulemaking 

stated that EPA was considering standards for achieving large reductions in oxides of nitrogen 

(NOx) and particulate matter (PM) through the use of technologies such as in-cylinder controls, 

aftertreatment, and low sulfur fuel, starting as early as 2011. 

On July 24, 2008, the State of California adopted new strict regulations for marine vessels within 

24 miles of shore. The Division expects that implementation of these new regulations for marine 

vessels will have benefits in Wyoming.

In October 2008, Member States of the International Maritime Organization (IMO) adopted new 

international standards for marine diesel engines and their fuels (2008 Amendments to MARPOL 

Annex VI) that apply globally, and establishes additional, more stringent emission requirements 

for ships that operate in specially-designated coastal areas where air quality problems are acute.

Under the new global standards, NOx emissions will be reduced, and the fuel sulfur cap will drop 

to 5,000 ppm in 2020 (pending a fuel availability review in 2018). Under the new geographic 

standards, ships operating in designated areas will be required to use engines that meet the most 

advanced technology-forcing standards for NOx emissions, and to use fuel with sulfur content at 

or below 1,000 ppm. 

On March 27, 2009, the United States submitted a joint proposal with Canada to the IMO to 

designate specific areas of our coastal waters as an Emission Control Area (ECA). Compared to 

fuels used in ships today, ECA standards will lead to a 96 percent reduction in sulfur in ships’ 

fuels, as well as a cut in emissions of PM by 85 percent and NOx by 80 percent. To achieve 

these reductions, ships must use fuel with no more than 1,000 parts per million sulfur beginning 

in 2015, and new ships will have to use advanced emission control technologies beginning in 

2016. 
168

8.3.3 Long-Term Control Strategies for BART Facilities

In addition to the control strategies identified in Chapter 6 (Best Available Retrofit Technology 

(BART)) as BART determinations, the following requirements will be established through 

permit conditions or orders from the Environmental Quality Council for the individual BART 

facilities listed below:

Laramie River Station: 

On March 8, 2010, Basin Electric Power Cooperative appealed the BART permit for the Laramie 

River Station before the Wyoming Environmental Quality Council (EQC). The Department of 

Environmental Quality entered into a settlement agreement on November 16, 2010 with Basin 

Electric Power Cooperative to modify the BART permit. On December 8, 2010, the Division 

held a State Implementation Plan (SIP) Hearing on Regional Haze. The SIP hearing was held in 

Cheyenne, Wyoming at the Laramie County Library, 2200 Pioneer Avenue. At that time, the 

Division collected public comment on the Regional Haze SIP revisions. 

After carefully considering all comments on revisions to the State Implementation Plan to 

address Regional Haze, the Division has determined that the following requirements for further 

NOx reduction taken from the Settlement Agreement Filed November 16, 2010 before the 

Wyoming EQC and incorporated into the EQC Order approving the Settlement, shall establish 

the NOx reduction requirements under the Long-Term Strategy of the Wyoming Regional Haze 

SIP for three units at Laramie River Station with respect to NOx and NOx only.

1. Total NOx emissions from Laramie River Station Units 1, 2 and 3 shall be further reduced 

to a plant-wide emission limit of 12,773 tons of NOx per year by December 31, 2017 and 

continuing thereafter, unless changed pursuant to new regulatory or permit requirements. 

2. Basin Electric Power Cooperative shall submit to the Division a permit application for 

the 12,773 ton plant-wide NOx emission limit at the Laramie River Station by December 

31, 2015. 

Jim Bridger Power Plant (Units 1 and 2): 

With respect to Bridger Units 1 and 2, PacifiCorp shall: (i) install SCR; (ii) install alternative 

add-on NOx control systems; or (iii) otherwise reduce NOx emissions not to exceed a 0.07 

lb/MMBtu 30-day rolling average NOx emissions rate. These installations shall occur, and/or 

this emission rate will be achieved, on Unit 2 prior to December 31, 2021 and Unit 1 prior to 

December 31, 2022. These installations shall occur, and/or this emission rate will be achieved,

in conjunction with PacifiCorp’s planned overhaul schedule for these units and pursuant to a 

construction or other permit application to be submitted by PacifiCorp to AQD no later than 

December 31, 2017. 
169

Jim Bridger Power Plant (Units 3 and 4): 

With respect to Bridger Units 3 and 4, PacifiCorp shall: (i) install SCR; (ii) install alternative 

add-on NOx control systems; or (iii) otherwise reduce NOx emissions to achieve a 0.07 

lb/MMBtu 30-day rolling average NOx emissions rate. These installations shall occur, and/or 

this emission rate will be achieved, on Unit 3 prior to December 31, 2015 and Unit 4 prior to 

December 31, 2016. These installations shall occur, and/or this emission rate will be achieved, 

in conjunction with PacifiCorp’s planned overhaul schedule for these units and pursuant to a 

construction or other permit application to be submitted by PacifiCorp to AQD no later than 

December 31, 2012. 

8.3.4 Evaluation of Control Strategies for Sources Identified in the Reasonable Progress - 

 Four-Factor Analysis 

The previous chapter evaluated certain non-BART sources through a four-factor analysis for 

additional controls, as was required by the Federal Regional Haze Rule. This evaluation was 

limited, in that no guidance was provided for identifying “significant sources”, and no 

contribution to visibility impairment thresholds were established (a potential fifth factor). The 

Division applied a “Quantity over Distance” (Q/D) process for screening out the most significant 

stationary source contributors, but that was only the first step in identifying control options. The 

Air Quality Administrator cannot, per Wyoming Statute 35-11-202, establish emission control 

requirements except through State rule or regulation. Furthermore, the Wyoming statute requires 

the Administrator to consider the character and degree of injury of the emissions involved. In 

this case, visibility modeling would be required to assess the degree of injury caused by the 

emissions. Modeling is not available at this time to determine impacts from emission reduction. 

The State believes it has taken a strong and reasonable first step in identifying potential 

contributors to visibility impairment, and that the next step of creating an appropriate rule or 

regulation will be accomplished in the next SIP revision. The visibility progress was designed as 

a long-term program going out to 2064. 

8.3.5 Oil and Gas

As discussed in Section 7.3.5, oil and gas production, which is not limited to just one area of 

Wyoming, is a large, important, and critical component of the State economy. However, the 

sources associated with oil and gas production emit NOx, and to a lesser extent, PM. An 

extensive fleet of field equipment and an array of processing plants operate continuously 

conducting exploration, production, and gathering activities. Exploration and drilling includes 

seismic studies, engineering, well testing, drilling operations, and transportation of personnel or 

equipment to and from sites. Oil and gas production includes operation, maintenance, and 

servicing of production properties, including transportation to and from sites. Sources include 

turbines, drill rig engines, glycol dehydrators, amine treatment units, flares and incinerators.

Understanding the sources and volume of emissions at oil and gas production sites is key to 

recognizing the impact that these emissions have on visibility. To better understand the 

emissions from these sources, the WRAP instituted a three-phase project. One of the issues was 
170

to quantify emission inventories from stationary and mobile equipment operated as part of oil 

and gas field operations. 

Phase I, which was completed in 2005, was an emission inventory project that estimated regional 

emissions from oil and gas field operations. Phase II, completed in late 2007, was an effort to 

more fully characterize the oil and gas field operations emissions. Phase III which began in late 

2007 with the Independent Petroleum Association of Mountain States (IPAMS) in conjunction 

with WRAP initiating a regional oil and gas emission inventory project is underway. The 

Division cannot complete the evaluation of oil and gas on visibility until this study has been 

completed.

8.3.6 Projection of the Net Effect on Visibility

The WRAP has projected the net effect on visibility from emission reductions by point, area and 

mobile sources throughout the WRAP region through 2018. The first emission projection 

inventory was compiled in 2006. The inventory was revised in 2007 to make preliminary 

evaluations of reasonable progress towards Class I areas visibility goals. The 2007 inventory 

focused on the most significant point and area sources of visibility impairing pollution in states 

and Native American Reservations. This effort included updating projections of electric 

generating units and incorporating known and presumed BART emission levels. Then, in the 

spring of 2009, the WRAP once again updated emission inventory projections for point and area 

sources in the WRAP region to give the most current assessment of reasonable progress towards 

visibility goals. Again, the updated projection inventory reflected new information about BART 

determinations and projection of future fossil fuel plants needed to achieve 2018 Federal 

electrical generation demands. More information on the specifics of the most recent emission 

inventory work collected for the 2018 visibility projections is contained in Chapter 4 of the 

Wyoming TSD in the April 29, 2009 ERG Technical Memorandum.

Chapter 5 of this Plan shows the specific results of the CMAQ modeling which was used to 

make all projections of visibility. Those results show anthropogenic emissions sources generally 

declining across the West through 2018. However, natural sources such as wildfires and dust, 

international sources in Mexico and Canada, global transport of emissions and off shore shipping 

in the Pacific Ocean all appear to offset improvements in visibility from controls on manmade 

sources. In spite of the large number of growing uncontrollable sources in the WRAP region, 

however, Wyoming does see a net visibility improvement at the Wyoming Class I areas through 

2018. The net effect of all of the reductions in the WRAP region, known at the time of the most 

recent model run is demonstrated in the WRAP Class I Summary Tables shown below for each 

of the Class I areas in Wyoming.
171

 Table 8.3.6-1. Class I Area Visibility Summary for YELL2 on 20% Worst Days

Class I Area Visibility Summary: Grand Teton NP, WY: Red Rock Lakes 

NWRW, MT: Teton W, WY: Yellowstone NP, WY

Visibility Conditions: Worst 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 Monitored Estimated Projected

2000-04 

Baseline 

Conditions

2064 

Natural 

Conditions

2018 

Uniform 

Rate of 

Progress 

Target

2018 

Projected 

Visibility 

Conditions

Baseline 

to 2018 

Change In 

Statewide 

Emissions

Baseline 

to 2018 

Change In 

Upwind 

Weighted 

Emissions2

Baseline to 

2018 Change 

In 

Anthropogenic 

Upwind 

Weighted 

Emissions2

 (Mm-1) (Mm-1) (Mm-1)1 (Mm-1) (tons / %) (%) (%)

Sulfate 4.26 0.76 3.35 3.71

-22,794

-15% -26% -32%

Nitrate 1.77 0.63 1.5 1.36

-39,861

-14% -26% -34%

Organic 

Carbon 13.48 4.61 11.02 12.87

-730

-3% -4% -29%

Elemental 

Carbon 2.48 0.43 1.97 2.2

-1,217

-15% -11% -50%

Fine Soil 0.95 1.02 0.97 1.04

5,223

31% 14% 25%

Coarse 

Material3 2.58 2.99 2.67 Not 

Applicable

13,394

27% 19% 42%

Sea Salt3 0.02 0.03 0.02

Not Applicable

Total 

Light 

Extinction 34.55 19.47 30.25 32.77

Deciview 11.76 6.44 10.52 11.23

1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 emissions scenarios.

3) Visibility projections not available due to model performance issues.

(WRAP TSS - http://vista.cira.colostate.edu/tss/)
172

 Table 8.3.6-2. Class I Area Visibility Summary for NOAB1 on 20% Worst Days

Class I Area Visibility Summary: North Absaroka W, WY: Washakie W, WY

Visibility Conditions: Worst 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 Monitored Estimated Projected

2000-04 

Baseline 

Conditions

2064 

Natural 

Conditions

2018 

Uniform 

Rate of 

Progress 

Target

2018 

Projected 

Visibility 

Conditions

Baseline 

to 2018 

Change In 

Statewide 

Emissions

Baseline 

to 2018 

Change In 

Upwind 

Weighted 

Emissions2

Baseline to 

2018 Change 

In 

Anthropogenic 

Upwind 

Weighted 

Emissions2

 (Mm-1) (Mm-1) (Mm-1)1 (Mm-1) (tons / %) (%) (%)

Sulfate 4.87 0.81 3.8 4.5

-22,794

-15% -11% -12%

Nitrate 1.61 0.75 1.4 1.29

-39,861

-14% -22% -28%

Organic 

Carbon 11.64 4.62 9.75 11

-730

-3% -5% -21%

Elemental 

Carbon 1.86 0.44 1.51 1.59

-1,217

-15% -17% -47%

Fine Soil 0.85 0.92 0.86 0.95

5,223

31% 17% 28%

Coarse 

Material3 2.91 3.44 3.03 Not 

Applicable

13,394

27% 20% 35%

Sea Salt3 0.01 0.03 0.01

Not Applicable

Total 

Light 

Extinction 32.74 20.02 29.21 31.25

Deciview 11.45 6.83 10.38 11

1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 emissions scenarios.

3) Visibility projections not available due to model performance issues.

(WRAP TSS - http://vista.cira.colostate.edu/tss/)
173

 Table 8.3.6-3. Class I Area Visibility Summary for BRID1 on 20% Worst Days

Class I Area Visibility Summary: Bridger W, WY: Fitzpatrick W, WY

Visibility Conditions: Worst 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 Monitored Estimated Projected

2000-04 

Baseline 

Conditions

2064 

Natural 

Conditions

2018 

Uniform 

Rate of 

Progress 

Target

2018 

Projected 

Visibility 

Conditions

Baseline 

to 2018 

Change In 

Statewide 

Emissions

Baseline 

to 2018 

Change In 

Upwind 

Weighted 

Emissions2

Baseline to 

2018 Change 

In 

Anthropogenic 

Upwind 

Weighted 

Emissions2

 (Mm-1) (Mm-1) (Mm-1)1 (Mm-1) (tons / %) (%) (%)

Sulfate 4.99 0.82 3.89 4.06

-22,794

-15% -31% -32%

Nitrate 1.43 0.79 1.27 1.24

-39,861

-14% -19% -21%

Organic 

Carbon 10.55 4.64 8.98 10.31

-730

-3% -4% -18%

Elemental 

Carbon 1.99 0.39 1.59 1.77

-1,217

-15% -17% -50%

Fine Soil 1.1 1.07 1.1 1.19

5,223

31% 13% 23%

Coarse 

Material3 2.51 2.67 2.55 Not 

Applicable

13,394

27% 16% 39%

Sea Salt3 0.04 0.04 0.04

Not Applicable

Total 

Light 

Extinction 31.6 19.42 28.23 30.12

Deciview 11.12 6.45 10.03 10.63

1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 emissions scenarios.

3) Visibility projections not available due to model performance issues.

(WRAP TSS - http://vista.cira.colostate.edu/tss/)

 
174

 Table 8.3.6-4. Class I Area Visibility Summary for YELL2 on 20% Best Days

Class I Area Visibility Summary: Grand Teton NP, WY: Red Rock Lakes 

NWRW, MT: Teton W, WY: Yellowstone NP, WY

Visibility Conditions: Best 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 Monitored Estimated Projected

2000-04 

Baseline 

Conditions

2064 

Natural 

Conditions

2018 

Uniform 

Rate of 

Progress 

Target

2018 

Projected 

Visibility 

Conditions

Baseline 

to 2018 

Change In 

Statewide 

Emissions

Baseline to 

2018 

Change In 

Upwind 

Weighted 

Emissions2

Baseline to 

2018 Change 

In 

Anthropogenic 

Upwind 

Weighted 

Emissions2

 (Mm-1) (Mm-1) (Mm-1)1 (Mm-1) (tons / %) (%) (%)

Sulfate 1.47 0.33

Not 

Applicable 1.43

-22,794

-15% -20% -26%

Nitrate 0.72 0.29

Not 

Applicable 0.57

-39,861

-14% -27% -36%

Organic 

Carbon 1.13 0.48

Not 

Applicable 1.1

-730

-3% -3% -28%

Elemental 

Carbon 0.31 0.07

Not 

Applicable 0.22

-1,217

-15% -10% -50%

Fine Soil 0.1 0.08

Not 

Applicable 0.14

5,223

31% 13% 25%

Coarse 

Material3 0.24 0.2

Not 

Applicable

Not 

Applicable

13,394

27% 18% 44%

Sea Salt3 0.01 0 

Not 

Applicable

Not Applicable

Total 

Light 

Extinction 12.99 10.45

Not 

Applicable 12.71

Deciview 2.58 0.43

Not 

Applicable 2.36

1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 emissions scenarios.

3) Visibility projections not available due to model performance issues.

(WRAP TSS - http://vista.cira.colostate.edu/tss/)
175

 Table 8.3.6-5. Class I Area Visibility Summary for NOAB1 on 20% Best Days

Class I Area Visibility Summary: North Absaroka W, WY: Washakie W, WY

Visibility Conditions: Best 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 Monitored Estimated Projected

2000-04 

Baseline 

Conditions

2064 

Natural 

Conditions

2018 

Uniform 

Rate of 

Progress 

Target

2018 

Projected 

Visibility 

Conditions

Baseline 

to 2018 

Change In 

Statewide 

Emissions

Baseline 

to 2018 

Change In 

Upwind 

Weighted 

Emissions2

Baseline to 

2018 Change 

In 

Anthropogenic 

Upwind 

Weighted 

Emissions2

 (Mm-1) (Mm-1) (Mm-1)1 (Mm-1) (tons / %) (%) (%)

Sulfate 1.11 0.27

Not 

Applicable 1.1

-22,794

-15% -22% -24%

Nitrate 0.37 0.23

Not 

Applicable 0.33

-39,861

-14% -28% -34%

Organic 

Carbon 0.8 0.46

Not 

Applicable 0.77

-730

-3% -6% -23%

Elemental

Carbon 0.16 0.05

Not 

Applicable 0.14

-1,217

-15% -21% -50%

Fine Soil 0.12 0.11

Not 

Applicable 0.15

5,223

31% 16% 26%

Coarse 

Material3 0.71 0.49

Not 

Applicable

Not 

Applicable

13,394

27% 19% 40%

Sea Salt3 0.02 0.02

Not

Applicable

Not Applicable

Total 

Light 

Extinction 12.28 10.61

Not 

Applicable 12.22

Deciview 2.02 0.58

Not 

Applicable 1.97

1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 emissions scenarios.

3) Visibility projections not available due to model performance issues.

(WRAP TSS - http://vista.cira.colostate.edu/tss/)
176

 Table 8.3.6-6. Class I Area Visibility Summary for BRID1 on 20% Best Days

Class I Area Visibility Summary: Bridger W, WY: Fitzpatrick W, WY

Visibility Conditions: Best 20% Days

RRF Calculation Method: Specific Days (EPA)

Emissions Scenarios: 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b)

 Monitored Estimated Projected

2000-04 

Baseline 

Conditions

2064 

Natural 

Conditions

2018 

Uniform 

Rate of 

Progress 

Target

2018 

Projected 

Visibility 

Conditions

Baseline 

to 2018 

Change In 

Statewide 

Emissions

Baseline 

to 2018 

Change In 

Upwind 

Weighted 

Emissions2

Baseline to 

2018 Change 

In 

Anthropogenic 

Upwind 

Weighted 

Emissions2

 (Mm-1) (Mm-1) (Mm-1)1 (Mm-1) (tons / %) (%) (%)

Sulfate 1.45 0.28

Not 

Applicable 1.35

-22,794

-15% -31% -33%

Nitrate 0.43 0.25

Not 

Applicable 0.41

-39,861

-14% -21% -25%

Organic 

Carbon 0.8 0.41

Not 

Applicable 0.8

-730

-3% -5% -23%

Elemental 

Carbon 0.36 0.08

Not 

Applicable 0.29

-1,217

-15% -20% -53%

Fine Soil 0.09 0.07

Not 

Applicable 0.12

5,223

31% 13% 23%

Coarse 

Material3 0.25 0.2

Not 

Applicable

Not 

Applicable

13,394

27% 16% 42%

Sea Salt3 0.01 0.01

Not 

Applicable

Not Applicable

Total 

Light 

Extinction 12.38 10.3

Not 

Applicable 12.22

Deciview 2.1 0.28

Not 

Applicable 1.97

1) 2018 Uniform Rate of Progress Target for Best 20% Days is not defined.

2) Results based on Weighted Emissions Potential analysis using the 2000-04 Baseline (plan02d) & 2018 PRPb (prp18b) 

emissions scenarios.

3) Visibility projections not available due to model performance issues.

(WRAP TSS - http://vista.cira.colostate.edu/tss/)
177

Since the Regional Haze process has proved to be much more complicated than the rule writers 

ever imagined, the entire process has taken longer than originally estimated. While most east 

coast states accepted EPA’s determination that CAIR satisfied BART for electric generating 

units, some western states are still going through the difficult case-by-case BART determinations 

for each EGU. As a result, the WRAP was not able to model all of the emission reductions from 

BART and State long-term strategies in the most recent modeling effort. In the State of 

Wyoming, significant additional NOx reductions will be made at the completion of the BART 

and long-term strategy. The overall cumulative NOx reductions from Wyoming sources over 

time are demonstrated in the figure below. Any additional future modeling will most likely 

demonstrate additional progress towards the 2018 visibility goals. 

Figure 8.3.6-7. Additional Cumulative NOx Reductions From Wyoming Sources
178

CHAPTER 9

ONGOING MONITORING AND EMISSION INVENTORY STRATEGY

The State of Wyoming will rely upon a Regional Planning Organization’s provision of adequate 

technical support to meet its commitment to conduct the analyses necessary to meet the 

requirements of 51.308(d)(4). 

The State of Wyoming will depend on the Inter-Agency Monitoring of PROtected Visual 

Environments (IMPROVE) monitoring program to collect and report aerosol monitoring data for 

long-term reasonable progress tracking as specified in 40 CFR 51.308(d)(4) of the Regional 

Haze Rule (RHR). Because the RHR is a long-term tracking program with an implementation 

period nominally set for 60 years, the Division expects that the IMPROVE program will provide 

data based on the following goals: 

1) Maintain a stable configuration of the individual monitors and sampling sites, and 

stability in network operations for the purpose of continuity in tracking reasonable 

progress trends; 

2) Assure sufficient data capture at each site of all visibility-impairing species;

3) Comply with EPA quality control and assurance requirements; and 

4) Prepare and disseminate periodic reports on IMPROVE program operations. 

The State of Wyoming is relying on the IMPROVE program to meet these monitoring operation 

and data collection goals, with the fundamental assumption that network data collection 

operations will not change, or if changed, will remain directly comparable to those operated by 

the IMPROVE program during the 2000-2004 RHR baseline period. Technical analyses and 

reasonable progress goals in this Implementation Plan for Regional Haze are based on data from 

these sites. As such, the State asks that the IMPROVE program identify potential issues 

affecting RHR implementation trends and/or notify the State before changes in the IMPROVE 

program affecting a RHR tracking site are made. 

Further, the State of Wyoming notes that the human resources to operate these monitors are 

provided by Federal Land Management agencies. Beyond that in-kind contribution, resources 

for operation and sample analysis of a complete and representative monitoring network of these 

long-term reasonable progress tracking sites by the IMPROVE program are a collaborative 

responsibility of EPA, states, tribes, and FLMs and the IMPROVE program steering committee. 

The State of Wyoming will collaborate with the EPA, FLMs, other states, tribes, and the 

IMPROVE committee to assure adequate and representative data collection and reporting by the 

IMPROVE program.
179

Figure 9-1. Links to Site Locations and Monitors 

Site 

Name Site Location Link

BRID1 VIEWS

WRAP TSS 

IMPROVE

http://vista.cira.colostate.edu/views/Web/SiteBrowser/SiteBrowser.aspx

http://vista.cira.colostate.edu/TSS/Tools/AOI.aspx

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/BRID/start.htm

NOAB1 VIEWS

WRAP TSS 

http://vista.cira.colostate.edu/views/Web/SiteBrowser/SiteBrowser.aspx

http://vista.cira.colostate.edu/TSS/Tools/AOI.aspx

YELL2 VIEWS

WRAP TSS 

IMPROVE

http://vista.cira.colostate.edu/views/Web/SiteBrowser/SiteBrowser.aspx

http://vista.cira.colostate.edu/TSS/Tools/AOI.aspx

http://vista.cira.colostate.edu/Datawarehouse/IMPROVE/Data/Photos/YELL/start.htm

Pursuant to 40 CFR 51.308(d)(4)(i), the State of Wyoming depends on the following IMPROVE 

program-operated monitors at the following sites for tracking RHR reasonable progress: 

 Table 9-1. The Wyoming IMPROVE Monitoring Network 

Site Code Class I Area Sponsor Elevation

(MSL) Start Date

BRID1 Bridger Wilderness

Fitzpatrick Wilderness USFS 2627 m8619 ft 3/2/1988 

NOAB1 North Absaroka Wilderness

Washakie Wilderness USFS 2483 m8146 ft 1/25/2000 

YELL2

Grand Teton National Park

Teton Wilderness 

Yellowstone National Park

NPS 2425 m 

7956 ft 7/1/1996 

In accordance with provisions of 40 CFR 51.308(d)(4)(ii), the State of Wyoming will use data 

reported by the IMPROVE program as part of the regional technical support analysis tools found 

at the Visibility Information Exchange Web System (VIEWS) and the Technical Support System 

(TSS), as well as other analysis tools and efforts sponsored by a Regional Planning Organization. 

Wyoming will participate in the ongoing regional analysis activities of a Regional Planning 

Organization to collectively assess and verify the progress toward reasonable progress goals, also 

supporting interstate consultation as the RHR is implemented, and collaborate with members of a 

Regional Planning Organization to ensure the continued operation of these technical support 

analysis tools and systems. 

Wyoming may conduct additional analyses as needed. 

The State of Wyoming will depend on the routine, timely reporting of haze monitoring data by 

the IMPROVE program for the reasonable progress tracking sites to the EPA air quality data 

systems, VIEWS and TSS as set forth in 40 CFR 51.308(d)(4)(iv). The State of Wyoming will 

collaborate with members of a Regional Planning Organization to ensure the continued operation 

of these technical support analysis tools and systems. 

Per requirements of 40 CFR 51.308(d)(4)(v), the State of Wyoming has prepared a statewide 

inventory of emissions that can reasonably be expected to cause or contribute to visibility 

impairment in Federal Class I areas. Chapter 4 of this Plan summarizes the emissions by 

pollutant and source category. 
180

The State of Wyoming commits to updating statewide emissions periodically. The updates will 

be used for state tracking of emission changes, trends, and input into a Regional Planning 

Organization’s evaluation of whether reasonable progress goals are being achieved and other 

regional analyses. The inventories will be updated every three years on the same schedule as the 

every three-year reporting required by EPA’s Consolidated Emissions Reporting Rule. 

As a member of a Regional Planning Organization, the State of Wyoming will use the Regional 

Planning Organization-sponsored data system(s) to store and access emission inventory data for 

the region. The State of Wyoming will also depend upon and participate in additional periodic 

collective emissions inventory efforts by a Regional Planning Organization. Further, the State of 

Wyoming will depend on and use the capabilities of a Regional Planning Organizationsponsored modeling center to simulate the air quality impacts of emissions for haze and other 

related air quality planning purposes. The State of Wyoming will collaborate with members of a

Regional Planning Organization to ensure the continued operation of these technical support 

analysis tools and systems. 

The State of Wyoming, in accordance with provisions of 40 CFR 51.308(d)(4)(vi), will track 

data related to RHR haze plan implementation for sources for which the State has regulatory 

authority, and will depend on the IMPROVE program and a Regional Planning Organizationsponsored collection and analysis efforts and data support systems for monitoring and emissions 

inventory data, respectively. To ensure the availability of data and analyses to report on 

visibility conditions and progress toward Class I area visibility goals, the State of Wyoming will 

collaborate with members of a Regional Planning Organization to ensure the continued operation 

of the IMPROVE program and Regional Planning Organization-sponsored technical support 

analysis tools and systems. 
181

CHAPTER 10

COMPREHENSIVE PERIODIC IMPLEMENTATION PLAN REVISIONS

40 CFR 51.308(f) requires the Division to revise its Regional Haze Implementation Plan and 

submit a Plan revision to the USEPA by July 31, 2018 and every ten years thereafter. In 

accordance with the requirements listed in Section 51.308(f) of the Federal rule for regional 

haze, Wyoming commits to revising and submitting this Regional Haze Implementation Plan by 

July 31, 2018 and every ten years thereafter. 

In addition, 51.308(g) requires periodic reports evaluating progress towards the reasonable 

progress goals established for each mandatory Class I area. In accordance with the requirements 

listed in 51.308(g) of the Federal rule for regional haze, the Division commits to submitting a 

report on reasonable progress to the USEPA every five years following the initial submittal of 

the SIP. The report will be in the form of a SIP revision. The reasonable progress report will 

evaluate the progress made towards the reasonable progress goal for each mandatory Class I area 

located within Wyoming and in each mandatory Class I area located outside Wyoming which 

may be affected by emissions from within Wyoming. 

The requirements listed in 51.308(g) include the following: 

1. A description of the status of implementation of all measures included in the 

implementation plan for achieving reasonable progress goals for mandatory Class I 

Federal areas both within and outside the state; 

2. Summary of emission reductions achieved thus far; 

3. Assessment of changes in visibility conditions at each Class I area (current vs. baseline), 

expressed as 5-year averages of annual values for least impaired and most impaired days;

4. Analysis of emissions changes over the 5-year period, identified by source or activity, 

using the most recent updated emissions inventory; 

5. Analysis of any significant changes in anthropogenic emissions in or out of the state 

which have impeded progress;

6. Assessment of the sufficiency of the implementation plan to meet reasonable progress 

goals;

7. Review of the State’s visibility monitoring strategy and any modifications to the strategy 

as necessary.
182

CHAPTER 11

WYOMING REGIONAL HAZE SIP DEVELOPMENT AND 

CONSULTATION PROCESS

11.1 State to State Consultation

Pursuant to 40 CFR Section 51.308(d)(iv), the State of Wyoming consulted with other states 

through a regional planning organization, the Western Regional Air Partnership (WRAP), in 

developing reasonable progress goals. The WRAP is a collaborative effort of tribal 

governments, State governments and various Federal agencies to implement the Grand Canyon 

Visibility Transport Commission's recommendations and to develop the technical and policy 

tools needed by western states and tribes to comply with the U.S. EPA’s regional haze 

regulations. The WRAP is administered jointly by the Western Governors’ Association and the 

National Tribal Environmental Council. WRAP activities are conducted by a network of 

committees and forums composed of WRAP members and stakeholders who represent a wide 

range of viewpoints. The WRAP recognizes that residents have the most to gain from improved 

visibility and that many solutions are best implemented at the local, state, tribal or regional level 

with public participation. The following states: Alaska, Arizona, California, Colorado, Idaho, 

Montana, Nevada, New Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and 

Wyoming have agreed to work together to address regional haze in the Western United States. 

The goals, objectives, management and decision making structure of the WRAP are described in 

Work Plans and a Strategic Plan provided in Chapter 1 of the Wyoming TSD. 

This consultation effort began with all states in the WRAP region contributing information to a 

technical support system (TSS) which allows all states to better understand the causes of haze 

and the levels of contribution from all sources to each Class I area. This project has involved 

many hours of consultation between states on regional emission inventories, monitoring and 

modeling to determine the causes of visibility impairment in each mandatory Class I Federal area 

in the regional planning area. WRAP forums involved in the technical consultation between 

states are as follows:

Air Pollution Prevention Forum Mobile Sources Forum 

Dust Emissions Forum Sources In and Near Class I Areas Forum 

Economic Analysis Forum Stationary Sources Forum 

Emissions Forum Technical Analysis Forum

Fire Emissions Forum 

The next step in state consultation in the development of reasonable progress goals was through 

the Implementation Work Group (IWG) of the WRAP. The State of Wyoming participated in 

the IWG which took the products of the technical consultation process discussed above and 

developed a process for establishing reasonable progress goals in the Western Class I areas. A 

description of that process and the determination of reasonable progress goals for each of the 

Class I areas in the State of Wyoming is described in Chapter 7. The following states have 

agreed to work together through the IWG in the development of reasonable progress goals: 

Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, North 

Dakota, Oregon, South Dakota, Utah, Washington, and Wyoming. 
183

Opportunities for consultation on development of reasonable progress goals provided through the 

WRAP Implementation Work Group have been documented in calls listed on the 

Implementation Work Group section of the WRAP website at: 

http://www.wrapair.org/forums/iwg/meetings.html. 

Pursuant to 40 CFR Section 51.308(d)(iv), the State of Wyoming also gave opportunity for 

neighboring states to comment on the State of Wyoming’s reasonable progress goals for each

Class I area located within the state. Opportunity for comment from other states was offered 

through a public hearing on the State Implementation Plan (SIP), held in accordance with 40 

CFR Section 51.102. The following states in the WRAP region were notified of the SIP public 

hearing: Alaska, Arizona, California, Colorado, Idaho, Montana, New Mexico, North Dakota, 

Oregon, South Dakota, Utah, Washington, Nevada, and Hawaii. The following states in the 

neighboring Central States Regional Planning Organization (CENRAP) were notified of the SIP 

public hearing: Iowa, Kansas, Minnesota, Missouri, Nebraska, Oklahoma, and Texas. 

Consultation correspondence between Wyoming and other states will be included in Chapter 11 

of the Wyoming TSD. Comments were received from the following states, on the State of

Wyoming’s reasonable progress goals for Class I areas located within the State of Wyoming. 

The State of Wyoming took the following actions to resolve the disagreement:

The State of Wyoming did not receive any comments from other states indicating disagreement 

on the reasonable progress goals established for the following Class I areas: Bridger Wilderness, 

Fitzpatrick Wilderness, Grand Teton National Park, North Absaroka Wilderness, Teton 

Wilderness, Washakie Wilderness, and Yellowstone National Park. 

 

Pursuant to 40 CFR 51.308(d)(3)(i), the State of Wyoming has participated in regional planning 

and coordination with other states in developing emission management strategies if emissions 

from within the state contribute to visibility impairment in a mandatory Class I Federal area 

outside the state, or if emissions from another state, regional planning organization, country, 

tribal area, or offshore location contribute to visibility impairment in any Class I Federal area 

within the state. This participation was through the Western Regional Air Partnership (WRAP). 

A more detailed description of the goals, objectives, management, and decision-making structure 

of the WRAP has been included in Work Plans and a Strategic Plan provided in Chapter 1 of the 

Wyoming TSD. The following WRAP forums have provided consultation opportunities between 

states on emission management strategies:

Air Pollution Prevention Forum Mobile Sources Forum 

Dust Emissions Forum Sources In and Near Class I Areas Forum 

Economic Analysis Forum Stationary Sources Forum 

Emissions Forum Technical Analysis Forum

Fire Emissions Forum 

Opportunities for consultation on emission strategies provided through the WRAP have been 

documented in calls and meetings on the WRAP website at: 

http://www.wrapair.org/cal/calendar.php. 
184

A description of the selected emission management strategies for the State of Wyoming is 

described in Chapter 8 of this Plan. The State of Wyoming views the development of 

coordinated emission management strategies to be a long-term commitment, and therefore, the 

State of Wyoming agrees to continue to participate in the WRAP or an alternative Regional 

Planning Organization in developing coordinated emission management strategies for SIP 

revisions in 2013 and 2018. 

Pursuant to 40 CFR 51.308(h)(2), the State of Wyoming has determined this first State 

Implementation Plan is adequate to ensure reasonable progress for the first planning period of the 

regional haze long-term planning effort which extends out to the year 2064. While emissions 

from sources outside of the State of Wyoming have resulted in a slower rate of improvement in 

visibility than the rate that would be needed to attain natural conditions by 2064, most of these 

emissions are beyond the control of any state in the regional planning area of the WRAP. The 

emission sources include: emissions from outside the WRAP domain; emissions from Canada 

and Mexico; emissions from wildfires and windblown dust; and emissions from offshore 

shipping. A more detailed description and quantification of these uncontrolled emissions is 

included in the Source Apportionment and Regional Haze Modeling chapter of this SIP. 

Additional strategies to address emissions beyond the control of any state in the WRAP under 

the jurisdiction of EPA are discussed in the Long-Term Strategy chapter of this SIP. 

Through the WRAP consultation process the State of Wyoming has reviewed and analyzed the 

contributions from other states that reasonably may cause or contribute to visibility impairment 

in Wyoming’s Class I areas. Wyoming acknowledges that the long-term strategies adopted by 

Colorado, South Dakota, and Idaho in their SIPs and approved by EPA will include emission 

reductions from a variety of sources that will reduce visibility impairment in Wyoming’s Class I 

areas.
185

 Figure 11.1-1. Regional Planning Organizations 

11.2 State and Federal Land Manager Coordination 

40 CFR Section 51.308(i) of the Regional Haze Rule requires coordination between states and 

the Federal Land Managers (FLMs). Wyoming has provided agency contacts to the FLMs as 

required under 51.308(i)(1). During the development of this Plan, the FLMs were consulted in 

accordance with the provisions of 51.308(i)(2). 

Numerous opportunities were provided by the Western Regional Air Partnership for FLMs to 

participate fully in the development of technical documents developed by the WRAP and 

included in this Plan. This included the ability to review and comment on these analyses, 

reports, and policies. A summary of WRAP-sponsored meetings and conference calls is 

provided on the WRAP website at: http://www.wrapair.org/cal/calendar.php. 

The State of Wyoming has provided an opportunity for consultation, in person and at least 60 

days prior to holding any public hearing on the SIP. As required by 40 CFR Section 

51.308(i)(3), the FLM comments and State responses, as well as email exchanges from the FLM 

community to the Division explaining their review preferences of the SIP, will be included in 

Chapter 11 of the Wyoming TSD. 

40 CFR Sections 51.308(f-h) establish requirements and timeframes for states to submit periodic 

SIP revisions and progress reports that evaluate progress toward the reasonable progress goal for 

each Class I area. As required by 40 CFR Section 51.308(i)(4), Wyoming will continue to 
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coordinate and consult with the FLMs during the development of these future progress reports 

and Plan revisions, as well as during the implementation of programs having the potential to 

contribute to visibility impairment in mandatory Class I areas. The progress and Plan reviews 

are to occur at five-year intervals, with a progress report between each required Plan revision. 

This consultation process shall provide on-going and timely opportunities to address the status of 

the control programs identified in this SIP, the development of future assessments of sources and 

impacts, and the development of additional control programs. The consultation will include the 

status of the following specific implementation items: 

1. Implementation of emissions strategies identified in the SIP as contributing to achieving 

improvement in the worst-day visibility.

2. Summary of major new permits issued.

3. Status of State actions to meet commitments for completing any future assessments or 

rulemakings on sources identified as likely contributors to visibility impairment, but not 

directly addressed in the most recent SIP revision. 

4. Any changes to the monitoring strategy or monitoring stations status that may affect 

tracking of reasonable progress. 

5. Work underway for preparing the 5-year review and/or 10-year revision.

6. Items for FLMs to consider or provide support for in preparation for any visibility 

protection SIP revisions (based on a 5-year review or the 10-year revision schedule under 

EPA’s RHR). 

7. Summary of topics discussion (meetings, emails, other records) covered in ongoing 

communications between the State and FLMs regarding implementation of the visibility 

program. 

The consultation will be coordinated with the designated visibility protection program 

coordinators for the National Park Service, U.S. Fish and Wildlife Service, Bureau of Land 

Management, and the U.S. Forest Service. At a minimum, the State of Wyoming will meet with 

the Federal Land Managers on an annual basis through the Western Regional Air Partnership or 

an alternative Regional Planning Organization. 

11.3 Tribal Consultation

Although tribal consultation is not required under the Regional Haze Rule, the Division views 

this as an important part of the consultation process, and actively pursued this during the 

development of the Regional Haze Plan. Not unlike the state consultation process, consultation 

with tribes involved reviewing major emission sources and regional haze strategies to address 

visibility issues. Consultation correspondence between Wyoming and tribal contacts will be 

included in Chapter 11 of the Wyoming TSD. 
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CHAPTER 12

DETERMINATION OF THE ADEQUACY OF THE EXISTING PLAN

Depending on the findings of the five-year progress report, Wyoming commits to taking one of 

the actions listed in 40 CFR 51.308(h). The findings of the five-year progress report will 

determine which action is appropriate and necessary. 

List of Possible Actions (40 CFR 51.308(h)) 

1. The Division determines that the existing SIP requires no further substantive revision in 

order to achieve established goals. The Division provides to the EPA Administrator a 

negative declaration that further revision of the SIP is not needed at this time. 

2. The Division determines that the existing SIP may be inadequate to ensure reasonable 

progress due to emissions from other states, which participated in the regional planning 

process. The Division provides notification to the EPA Administrator and the states that 

participated in regional planning. The Division collaborates with states and FLMs 

through the regional planning process to address the SIP’s deficiencies. 

3. The Division determines that the current SIP may be inadequate to ensure reasonable 

progress due to emissions from another country. The Division provides notification, 

along with available information, to the EPA Administrator.

4. The Division determines that the existing SIP is inadequate to ensure reasonable progress 

due to emissions within the state. The Division will consult with FLMs and revise its SIP 

to address the Plan’s deficiencies within one year.
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CHAPTER 13

TECHNICAL INFORMATION AND DATA RELIED UPON IN THIS PLAN

This chapter describes the information relied upon by the Division in developing this Regional 

Haze Plan. The first portion of this chapter describes the Western Regional Air Partnership 

(WRAP) and the work products of this organization which have been utilized by the Division. 

13.1 The WRAP and Technical Support

The WRAP is a voluntary organization of western states, tribes and Federal agencies which was 

formed in 1997 as the successor to the Grand Canyon Visibility Transport Commission 

(GCVTC). It is a regional planning organization that provides assistance to western states like 

Wyoming in the preparation and implementation of Regional Haze Plans. The WRAP is also 

instigating regional planning processes to improve visibility in all Western Class I areas by 

providing the technical and policy tools needed by states and tribes to implement the Federal 

Regional Haze Rule. The WRAP is administered jointly by the Western Governors’ Association 

(WGA) and the National Tribal Environmental Council (NTEC). 

The WRAP is comprised of western states, tribes and Federal agencies. The states include 

Alaska, Arizona, California, Colorado, Idaho, Montana, New Mexico, North Dakota, Oregon, 

South Dakota, Utah, Washington, and Wyoming. Tribal board members include Campo Band of 

Kumeyaay Indians, Confederated Salish and Kootenai Tribes, Cortina Indian Rancheria, Hopi 

Tribe, Hualapai Nation of the Grand Canyon, Native Village of Shungnak, Nez Perce Tribe, 

Northern Cheyenne Tribe, Orutsararmiut Native Council, Pueblo of Acoma, Pueblo of San 

Felipe, Pueblo of Zuni, and Shoshone-Bannock Tribes of Fort Hall. Representatives of other 

tribes participate on WRAP forums and committees. Participation is encouraged throughout the 

western states and tribes. Federal participants include the Department of Interior (National Park 

Service and Fish & Wildlife Service), the Department of Agriculture (Forest Service), and the 

Environmental Protection Agency. 

13.2 WRAP Committees and Work Groups

• Air Managers Committee

The Air Managers Committee (formerly the Northern Air Managers Committee) is made up of 

state and tribal caucuses, each representing the interests of state and tribal air managers. The 

committee is expected to provide air managers with a forum for discussing WRAP related 

matters of concern to them. These matters may cover a spectrum of air quality issues. The 

committee also provides a mechanism for communication and guidance to the technical and 

policy forums as to what air managers believe is needed to support their regional planning 

efforts.

• Communications Committee

The WRAP Communications Committee facilitates the exchange of information between the 

standing committees and forums of the WRAP, and is also charged with developing materials 
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that help the general public understand the WRAP process and take part in its decision making. 

Some of the products of the Communications Committee have included outreach materials to 

encourage direct participation, the development of internal and external communications plans 

and the construction of the WRAP website.

• Planning Team

The Planning Team is convened as needed to address long-term planning and administrative 

issues, such as annual WRAP work plans and the WRAP strategic plan. Some of the functions 

performed by the Planning Team were previously performed by the Coordinating Group, which 

no longer exists. 

• Initiatives Oversight Committee

The Initiatives Oversight Committee (IOC) provides general oversight for the coordination and 

development of air quality strategies necessary to promote the implementation of the Grand 

Canyon Visibility Transport Commission’s recommendations. The IOC oversees the 

development of other air quality policies and strategies at the direction of the WRAP, refers 

issues to forums, reviews recommendations from forums and makes recommendations to the 

WRAP.

• Technical Oversight Committee

The Technical Oversight Committee (TOC) provides general oversight to the technical activities 

of the WRAP. The TOC identifies technical issues and tasks necessary to support the activities 

of the WRAP and refers these issues to the technical forums. The TOC identifies issues to be 

addressed by the forums, based on input, priorities, and directions from the WRAP. The TOC 

reviews any recommendations made by the forums and subsequently makes its own 

recommendations to the WRAP. 

• Implementation Work Group 

The purpose of the WRAP Air Managers Committee Implementation Work Group is to help 

states and tribes prepare their Regional Haze Implementation Plans to meet the requirements of 

40 CFR 51.308 and 401 CFR 51.309(g). The work group is comprised of state and tribal 

representatives to accommodate the needs of states and tribes by recognizing the variety of 

regulatory and statutory authorities and range of technical and policy expertise. 

• Oil and Gas Emissions Work Group 

Significant air pollutant emissions come from production of oil and gas from wells located on 

state-regulated and tribal lands, as well as from the interconnected gathering networks interlacing 

the WRAP region. These emissions result from operation of an extensive fleet of field 

equipment and an array of processing plants, operating continuously across the West. These 

field operations include exploration, production, and gathering activities. 
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Historically, emissions from large stationary point sources processing this energy for the oil and 

gas fuels markets were pretty well quantified through existing regulatory agency permitting 

programs, but quite a number of pieces of smaller oil and gas field equipment (compressor 

engines, drill rigs, heaters, dehydrators, flares, etc.) traditionally fell below agency permitting 

thresholds. Although individual emissions from this field equipment could be considered minor, 

with increasing energy demand and continuing oil and gas field development the cumulative 

totals for oil and gas basins, producing states and the WRAP region as a whole were thought to 

present an entirely different picture. But prior to WRAP involvement, present and future area 

source emissions from western field oil and gas production operations were generally 

incompletely quantified.

The WRAP recognized this deficiency and formed the Oil and Gas Emissions Work Group to 

look more closely at this industry and take steps to address the deficiencies. In late 2005 the 

WRAP completed the Phase I oil and gas emission inventory project to estimate for the first 

time, regional emission totals from these field operations. As a “first cut” Phase I had a number 

of uncertainties identified, thus the work group subsequently initiated the Phase II project, 

completed in fall 2007, to more fully characterize the oil and gas field operations emissions. 

These WRAP inventories identified over 100,000 TPY of NOx emissions in the WRAP region 

which had not previously been included in regional air quality assessments, as well as significant 

totals of other air pollutant species (VOC’s primarily) critical in the evaluation of regional haze 

and other air quality management issues.

Members of the Independent Petroleum Association of Mountain States (IPAMS) felt that still 

more improvement in the accuracy of these emission estimates was needed and available. So in 

late 2007 IPAMS initiated a Phase III regional oil and gas emission inventory project funded by 

their organization. The project was undertaken in conjunction with the WRAP to assure that the 

products from Phase III were widely distributed among non-industry stakeholders (state/local 

agencies, tribal air programs, Federal Land Managers, environmental groups and EPA). This 

wider participation was viewed as necessary to assure review and feedback such that the final 

inventories were understood and more universally accepted by those parties interested in and 

affected by oil and gas development in the Intermountain West. 

• Tribal Data Development Work Group 

The mission of this work group is to assist and advise WRAP on gathering tribal air quality data 

and other air quality issues related to the WRAP mission from tribes in the WRAP area. They 

work with the other WRAP forum and non-tribal communities to improve understanding 

communities of protocols and processes for obtaining and using tribal data. In addition to 

assisting in gathering existing air quality and air emissions data, this work group aids in devising 

plans for filling the gaps in the tribal data.
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13.3 WRAP Forums

• Air Pollution Prevention Forum 

The Air Pollution Prevention Forum (AP2) was created by the WRAP to examine barriers to use 

of renewable energy and energy efficient technologies, identify actions to overcome such 

barriers, and recommend potential renewable energy and energy efficiency programs and 

policies that could result in a reduction of air pollution emissions from energy production and 

energy end-use sectors in the Grand Canyon Visibility Transport Region. 

• Dust Emissions Joint Forum 

In the summer of 2002, the WRAP Oversight Committees established a Dust Emissions Joint 

Forum to consolidate the WRAP’s efforts involving dust. Previously, three forums had worked 

on dust issues: the Mobile Sources Forum, the Research and Development Forum, and the 

Emissions Forum. The new DEJF concentrates on improving how dust emissions are estimated 

and subsequently treated by air quality models. The forum also examines strategies to 

effectively reduce the impact of dust emissions on visibility in Class I areas.

• Economic Analysis Forum 

The mission of the Economic Analysis Forum (EAF) is to provide the WRAP and WRAP 

forums with projections of econometric parameters needed to forecast changes in emissions, and 

assessments of the economic effects of pollution controls on the region and sub-regions, 

including Indian Country. Specifically, the EAF is seeking to: develop a better definition of 

what states, tribes and stakeholders expect from the economic analyses provided with WRAP 

products; develop a common economic analysis framework, which will include incorporating 

existing studies’ economic analyses; assist states and tribes as they prepare their Implementation 

Plans; and provide overall analytical support and analysis as states and tribes gage the economic 

components of their Regional Haze Plans.

• Emissions Forum 

The Emissions Forum oversees the development of a comprehensive emissions tracking and 

forecasting system which can be utilized by the WRAP, or its member entities, monitors the 

trends in actual emissions, and forecasts the anticipated emissions which will result from current 

regulatory requirements and alternative control strategies. In addition, this forum is responsible 

for the oversight of the assembly and quality assurance of the emissions inventories and forecasts 

to be utilized by the WRAP forums. 

• Fire Emissions Joint Forum 

The Fire Emissions Joint Forum (FEJF) was formed to assist the WRAP in addressing the Grand 

Canyon Visibility Transport Commission’s (GCVTC) Recommendations on fire. The term fire 

refers inclusively to wildfire, prescribed natural fire/wildland fire managed for resource benefits, 

prescribed fire, and agricultural fire. The forum addresses a broad definition of smoke effects 
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which includes consideration of public nuisance, public health and visibility/regional haze. The 

FEJF follows its consensus based Work Plan which addresses four major topics. 

Criteria for implementation of different stringencies of smoke management programs are being

developed as well as specific smoke management program elements. Fire emissions are being

directly assessed in terms of pollutant estimation methods, emission projections and tracking. 

An assessment is being done of the potential applicability and utility of non-burning alternatives 

to fire. The use of alternatives and other emission reduction methods relates directly to the 

potential application of annual emission goals. 

A public education and outreach program related to fire and smoke effects is being developed. 

All recommendations to the WRAP and methods developed by the forum are intended for 

Western U.S. application and represent a consensus of FEJF members. Collaboration and 

cooperation with other entities addressing smoke management issues in the West have been 

included in the Work Plan of the FEJF. 

• Mobile Sources Forum 

The Mobile Sources Forum (MSF) investigates and recommends mobile source emission control 

measures. Mobile sources includes both on-road sources (e.g., cars, trucks, buses, and 

motorcycles) and off-road sources (e.g., aircraft and its support equipment, locomotives, 

commercial marine and pleasure craft, and equipment used for construction, logging, mining, 

agriculture, and lawn and garden care). Since emission standards for new on-road and off-road 

sources can only be set by the U.S. EPA (on-road standards can also be set by California), the 

MSF focuses more on the impact and treatment of existing sources, especially off-road sources. 

The MSF also participates in technical activities related to mobile sources. During its first 

couple of years (2000-02), the MSF led the development of a WRAP-wide mobile source 

emission inventory and worked with the Air Quality Modeling Forum to define and analyze the 

significance of mobile sources with respect to the requirements of §309 of the Regional Haze 

Rule.

• Sources In and Near Class I Areas Forum 

The Grand Canyon Visibility Transportation Commission (GCVTC) developed 

recommendations to address emissions from sources in and near Class I areas on the Colorado 

Plateau. The Sources In and Near Class I Areas Forum (In and Near Forum) helps implement 

those recommendations by working with parks and local communities to develop and implement 

strategies to minimize emissions and the resulting visibility impacts.

• Stationary Sources Joint Forum

The Stationary Sources Joint Forum (SSJF) was established in January 2004 and replaces the 

Market Trading Forum (MTF). The SSJF focuses more broadly on stationary source issues 

throughout the WRAP and their relationship to Section 308 SIP requirements. Major topics for 

the SSJF include BART, reasonable progress for stationary sources, technical analyses, and 
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evaluating the effect of and integration with other regulatory and legislative developments at the 

national level.

• Technical Analysis Forum

The TAF coordinates and manages the processing, display, delivery, and explanation of technical 

data for regional haze planning activities. The TAF assumes responsibility for combining the 

participants and maintaining the activities and ongoing projects of the Ambient Air Monitoring 

& Reporting Forum, the Air Quality Modeling Forum, and the Attribution of Haze Workgroup. 

13.4 WRAP TSS

The primary purpose of the TSS is to provide key summary analytical results and methods 

documentation for the required technical elements of the Regional Haze Rule, to support the 

preparation, completion, evaluation, and implementation of the Regional Haze Implementation 

Plans to improve visibility in Class I areas. The TSS provides technical results prepared using a 

regional approach, to include summaries and analysis of the comprehensive datasets used to 

identify the sources and regions contributing to regional haze in the Western Regional Air 

Partnership (WRAP) region.

The secondary purpose of the TSS is to be the one-stop-shop for access, visualization, analysis, 

and retrieval of the technical data and regional analytical results prepared by WRAP Forums and 

Workgroups in support of regional haze planning in the West. The TSS specifically summarizes 

results and consolidates information about air quality monitoring, meteorological and receptor 

modeling data analyses, emissions inventories and models, and gridded air quality/visibility 

regional modeling simulations. These copious and diverse data are integrated for application to 

air quality planning purposes by prioritizing and refining key information and results into 

explanatory tools. A detailed description of the TSS website, “WRAP Technical Support System 

Web Site Description (November 16, 2009 Draft)”, can be found in Chapter 13 of the Wyoming 

TSD.

13.5 IMPROVE Monitoring

13.5.1 Background on IMPROVE Monitoring

The Interagency Monitoring of Protected Visual Environments (IMPROVE) program is a 

cooperative measurement effort governed by a steering committee composed of representatives 

from Federal and regional-state organizations. The IMPROVE monitoring program was 

established in 1985 to aid the creation of Federal and State Implementation Plans for the 

protection of visibility in Class I areas (156 national parks and wilderness areas) as stipulated in 

the 1977 amendments to the Clean Air Act. 

The objectives of IMPROVE are: (1) to establish current visibility and aerosol conditions in 

mandatory Class I areas; (2) to identify chemical species and emission sources responsible for 

existing man-made visibility impairment; (3) to document long-term trends for assessing 

progress towards the national visibility goal; (4) and with the enactment of the Regional Haze 
194

Rule, to provide regional haze monitoring representing all visibility-protected Federal Class I 

areas where practical. IMPROVE has also been a key participant in visibility-related research, 

including the advancement of monitoring instrumentation, analysis techniques, visibility 

modeling, policy formulation and source attribution field studies. 

An IMPROVE sampler, depicted below, consists of four separate modules used for collecting the 

various pollutant species. 

 Figure 13.5.1-1. Schematic of the IMPROVE Sampler Showing the Four 

 Modules With Separate Inlets and Pumps

(http://vista.cira.colostate.edu/improve/Overview/IMPROVEProgram_files/frame.htm) 

The IMPROVE monitoring network consists of aerosol and optical samplers. The network 

began operating in 1988 with 20 monitoring sites in Class I areas. By 1999 the network 

expanded to 30 monitoring sites in Class I areas and 40 sites using IMPROVE site and sampling 

protocols operated by Federal and State agencies. With the enactment of the Regional Haze 

Rules the IMPROVE network has been expanded by 80 new sites. Photographs of Wyoming 

Class I area IMPROVE monitoring sites are provided in Chapter 2. 

13.6 Formula for Reconstructed Light Extinction

The IMPROVE program has developed methods for estimating light extinction from speciated 

aerosol and relative humidity data. The three most common metrics used to describe visibility 

impairment are:

 Extinction (bext) - Extinction is a measure of the fraction of light lost per unit length 

along a sight path due to scattering and absorption by gases and particles, expressed in 

inverse Megameters (Mm-1). This metric is useful for representing the contribution of 
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each aerosol species to visibility impairment and can be practically thought of as the units 

of light lost in a million meter distance.

 Visual Range (VR) - Visual range is the greatest distance a large black object can be 

seen on the horizon, expressed in kilometers (km) or miles (mi).

 Deciview (dv) - This is the metric used for tracking regional haze in the Regional Haze 

Rule. The deciview index was designed to be linear with respect to human perception of 

visibility. A one deciview change is approximately equivalent to a 10% change in 

extinction, whether visibility is good or poor. A one deciview change in visibility is 

generally considered to be the minimum change the average person can detect with the 

naked eye. 

The IMPROVE network estimates light extinction based upon the measured mass of various 

contributing aerosol species. EPA’s 2003 guidance for calculating light extinction is based on 

the original protocol defined by the IMPROVE program in 1988. (For further information, see 

http://vista.cira.colostate.edu/improve/Publications/GuidanceDocs/guidancedocs.htm.) In 

December 2005, the IMPROVE Steering Committee voted to adopt a revised algorithm for use 

by IMPROVE as an alternative to the original approach.

The revised algorithm for estimating light extinction is calculated as recommended for use by the 

IMPROVE steering committee using the following equations:

 bext ≈ 2.2 x fs(RH) x [Small Amm. Sulfate] + 4.8 x fL(RH) x [Large Amm. Sulfate]

 + 2.4 x fs(RH) x [Small Amm. Nitrate] + 5.1 x fL(RH) x [Large Amm. Nitrate]

 + 2.8 x [Small POM] + 6.1 x [Large POM] 

 + 10 x [EC] 

 + 1 x [Soil] 

 + 1.7 x fss(RH) x [Sea Salt]

 + 0.6 x [CM]

 + 0.33 x [NO2(ppb)] 

 + Rayleigh Scattering (Site Specific)

The revised algorithm splits ammonium sulfate, ammonium nitrate, and POM concentrations 

into small and large size fractions as follows:
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13.7 Wyoming IMPROVE Monitoring Network

In Wyoming there are three IMPROVE monitors which are described in the table below. There 

are seven Class I areas in Wyoming; therefore, some monitors serve multiple Class I areas. 

Although it is desirable to have one monitor for each Class I area, in most cases one monitor is 

“representative” of haze conditions in nearby Class I areas. Locations and descriptions of the 

IMPROVE monitors were presented in Chapter 2. 

 Table 13.7-1. The Wyoming IMPROVE Monitoring Network

Site Code Class I Area Sponsor Elevation

(MSL) Start Date

BRID1 Bridger Wilderness

Fitzpatrick Wilderness USFS 2627 m8619 ft 3/2/1988 

NOAB1 North Absaroka Wilderness

Washakie Wilderness USFS 2483 m8146 ft 1/25/2000 

YELL2

Grand Teton National Park

Teton Wilderness 

Yellowstone National Park

NPS 2425 m 

7956 ft 7/1/1996