PROGRESS REPORT FOR UTAH’S STATE 

IMPLEMENTATION PLAN FOR REGIONAL HAZE

September 22, 2014

Prepared by staff of the:

Utah Division of Air Quality

Utah Department of Environmental Quality

195 North 1950 West

Salt Lake City, UT 84116
Table of Contents

1.0 INTRODUCTION....................................................................................... Error! Bookmark not defined.

1.1 State Implementation Plan Requirements for the 5-Year Progress Report.......................................1

2.0 UTAH CLASS I AREAS ..............................................................................................................................2

2.1 Progress Towards Reasonable Progress Goals (40 CFR §51.309(d)(10(i)).........................................3

3.0 REGIONAL HAZE PROGRESS REPORT ................................................................................................4

3.1 40 CFR § 51.309(D)(10)(i) Progress Report Requirements ................................................................4

3.2 Status of Implementation Control Measures: 40 CFR §51.309(d)(10)(i)(A).....................................5

Enforceability of Utah’s Measures............................................................................................................7

3.3 Summary of Emission Reduction Achieved: 40 CFR § 51.309(d)(10)(i)(B)........................................7

3.4 Assessment of Visibility Conditions: 40 CFR § 51.309(d)(10)(i)(C)..................................................11

3.4.1 Current Visibility Conditions for the Most and Least Impaired Days....................................12

3.4.2 Differences Between Current Visibility Conditions for the Most and Least 

Impaired Days and Baseline Visibility Conditions...............................................................................14

3.4.3 Change in Visibility Impairment for the Most Impaired and Least Impaired Days 

Over the Past Five Years .....................................................................................................................18

3.5 Analysis of Emissions: 40 CFR 40 CFR § 51.309(d)(10)(i)(D)............................................................19

3.6 Changes to Anthropogenic Emissions: § 51.309(d)(10)(i)(E) ...........................................................32

3.7 Assessment of Current SIP Strategy: § 51.309(d)(10)(i)(F) .............................................................32

3.8 Assessment of Current Monitoring Strategy: § 51.309(d)(10)(i)(G) ...............................................36

3.9 Determination of Adequacy: § 51.309(d)(10)(ii).............................................................................36

4.0 REGIONAL SUMMARY FOR 309 GCVTC CLASS I AREAS...................................................................37

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Tables

Table 2.1. Utah Class I Area IMPROVE Sites Visibility Conditions for the 20% Most and Least Impaired 

days – Including 2010 to 2012. .....................................................................................................................4

Table 3.1, Utah Class I Area IMPROVE Sites, Current Visibility Conditions, 2005-2009 Progress Period,

20% Most Impaired Days............................................................................................................................13

Table 3.2, Utah Class I Area IMPROVE Sites, Current Visibility Conditions, 2005-2009 Progress Period,

20% Least Impaired Days............................................................................................................................13

Table 3.3. Utah Class I Area IMPROVE Sites, Difference in Aerosol Extinction by Species, 2000-2004 

Baseline Period to 2005-2009 Progress Period...........................................................................................15

Table 3.4. Utah Class I Area IMPROVE Sites, Difference in Aerosol Extinction by Species, 2000-2004 

Baseline Period to 2005-2009 Progress Period, 20% Least Impaired Days................................................15

Table 3.5. Utah Class I Area IMPROVE Sites, Change in Aerosol Extinction by Species, 200-2009 Annual 

Average Trends...........................................................................................................................................19

Table 3.6. Utah, Pollutants, Aerosol Species, and Major Sources..............................................................20

Table 3.7. Sulfur Dioxide Emissions by Category ........................................................................................23

Table 3.8. Oxides of Nitrogen Emissions by Category ................................................................................24

Table 3.9. Ammonia Emissions by Category ...............................................................................................25

Table 3.10. Volatile Organic Compound Emissions by Category ................................................................26

Table 3.11. Primary Organic Aerosol Emissions by Category .....................................................................27

Table 3.12. Elemental Carbon Emissions by Category................................................................................28

Table 3.13. Fine Soil Emissions by Category ...............................................................................................29

Table 3.14. Coarse Mass Emissions by Category ........................................................................................30

Table 3.15. Average extinction for 20% Worst Days for the Current Progress Period of 2005-2009 ........32

Table 3.16. Utah Class I Area IMPROVE Sites Visibility conditions – 20% Most and Least Impaired Days 

Including 2010 to 2012 data .......................................................................................................................35

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Table 3.17. Utah CIAs and Representative IMPROVE Monitors ................................................................36

Table 4.1. Colorado Plateau Class I Areas and Representative IMPROVE Monitors ..................................38

Table 4.2. Colorado Plateau Class I Area IMPROVE Sites, Current Visibility Conditions, 2005-2009 

Progress Period, 20% Most Impaired Days.................................................................................................42

Table 4.3. Colorado Plateau Class I Area IMPROVE Sites, Current Visibility Conditions, 2005-2009 

Progress Period, 20% Least Impaired Days.................................................................................................43

Table 4.4. Colorado Plateau Class I Area IMPROVE Sites, Difference in Aerosol Extinction by Species, 

2000-2004 Baseline Period to 2005-2009 Progress Period, 20% Most Impaired Days..............................44

Table 4.5. Colorado Plateau Class I Area IMPROVE Sites, Difference in Aerosol Extinction by Species, 

2000-20004 Baseline Period to 2005-2009 Progress Period, 20% Least Impaired Days............................45

Table 4.6. Colorado Plateau Class I Area IMPROVE Sites, Change in Aerosol Extinction by Species, 2000-

2009 Annual Average Trends......................................................................................................................46

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Figures

Figure 2.1. Map Depicting Federal Class I Areas and Representative IMPROVE Monitors in Utah.............2

Figure 3.1. Change in Deciview Extinction between Baseline Period Average (2000-2004) and the First 

Progress Period Average (2005-2009) for the 20% Worst Visibility Days.....................................................8

Figure 3.2. Change in Deciview Extinction between Baseline Period Average (2000-2004) and the First 

Progress Period Average (2005-2009) for the 20% Best Visibility Days .......................................................9

Figure 3.3. Regional Average of Aerosol Extinction by Pollutant for Baseline Period average (2000-2004) 

for 20% Worst Days. ...................................................................................................................................10

Figure 3.4. Regional Average of Aerosol Extinction by Pollutant for the First Progress Period Average 

(2005-2009) for 20% Worst Days................................................................................................................10

Figure 3.5. Magnitude of Aerosol Extinction Species that have Decreased Between the Baseline Average 

(2000-2004) and the First Progress Period Average (2005-2009) for the 20% Worst Days. ......................11

Figure 3.6. Average Extinction for Current Progress Period (2005-2009) for the Worst (Most Impaired) 

and Best (Least Impaired) Days Measured at Utah Class I Area IMPROVE Sites........................................14

Figure 3.7. Average Extinction for Baseline and Progress Period Extinction for Worst (Most Impaired) 

Days Measured at Utah Class I Area IMPROVE Sites. .................................................................................16

Figure 3.8. Difference between Average Extinction for Current Progress Period (2005-2009) and Baseline 

Period (2000-2004) for the Worst (Most Impaired) Days Measured at Utah Class I Area IMPROVE Sites.16

Figure 3.9. Average Extinction for Baseline and Progress Period Extinction for Best (Least Impaired) Days 

Measured at Utah Class I Area IMPROVE Sites...........................................................................................17

Figure 3.10. Difference Between Average Extinction for Current Progress Period (2005-2009) and 

Baseline Period (2000-2004) for the Best (Least Impaired) Days Measured at Utah Class I Area IMPROVE 

Sites.............................................................................................................................................................17

Figure 3.11. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for Sulfur 

Dioxide by Source Category for Utah..........................................................................................................23

Figure 3.12. 2002 and 2008 Emissions and Difference between Emissions Inventory Totals, for Oxides of 

Nitrogen by Source Category for Utah........................................................................................................24

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Figure 3.13. 2002-2008 Emission and Difference between Emission Inventory Totals, for Ammonia by 

Source Category for Utah............................................................................................................................25

Figure 3.14. 2002-2008 Emission and Difference between Emission Inventory Totals, for Volatile Organic 

Compounds by Source Category for Utah ..................................................................................................26

Figure 3.15. 2002-2008 Emission and Difference between Emission Inventory Totals, for Primary Organic 

Aerosol by Source Category for Utah .........................................................................................................27

Figure 3.16. 2002-2008 Emission and Difference between Emission Inventory Totals, for Elemental 

Carbon by Source Category for Utah ..........................................................................................................28

Figure 3.17. 2002-2008 Emission and Difference between Emission Inventory Totals, for Fine Soil by 

Source Category for Utah............................................................................................................................29

Figure 3.18. 2002-2008 Emission and Difference between Emission Inventory Totals, for Coarse Mass by 

Source Category for Utah............................................................................................................................30

Figure 3.19. Sum of EGU Emissions of SO2 and NOx Reported between 1996 and 2010..........................31

Figure 3.20. Annual and 5-Year Period Averages for the 20% Worst Days at Canyonlands and Arches 

National Parks (CANY1 IMPROVE Site) .......................................................................................................33

Figure 3.21. Annual and 5-Year Period Averages for the 20% Worst Days at Bryce Canyon National Park 

(BRCA1 IMPROVE Site)................................................................................................................................33

Figure 3.22. Annual and 5-Year Period Averages for the 20% Worst Days at Capitol Reef (CAPI1 

IMPROVE Site).............................................................................................................................................34

Figure 4.1. Map Depicting Colorado Plateau Class I Areas and Representative IMPROVE Monitors in 

Arizona, Colorado, New Mexico and Utah..................................................................................................39

Figure 4.2. Regional Average of Aerosol Extinction by Pollutant for the First Progress Period Average 

(2005-2009) for 20% worst days.................................................................................................................41

Figure 4.3. Regional Average of aerosol Extinction by Pollutant for First Progress Period Average (2005-

2009) for 20% Best Days.............................................................................................................................41

Figure 4.4 Chart Depicting Annual Average Ammonium Sulfate Concentrations for the 20% Worst Days 

as Measured at the Colorado Plateau CIA IMPROVE Sites.........................................................................47

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Figure 4.5. Chart Depicting 3-Year Average Sum of SO2 Emissions for New Mexico, Utah and Wyoming 

and the City of Albuquerque/Bernalillo County as Compared to the Section 309 SIP SO2 Milestones.....48

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1.0 INTRODUCTION

On December 12, 2003, the State of Utah submitted a Regional Haze State Implementation Plan (RH SIP)

to meet the requirements of 40 CFR 51.309 (309 SIP) to improve visibility in Utah’s five Federal Class I 

Areas. The 2003 version of the 309 SIP and subsequent revisions to it address the first phase of 

requirements, with an emphasis on stationary source sulfur dioxide (SO2) emission reductions, smoke 

management, and a focus on improving visibility on the Colorado Plateau. 

On December 14, 2012, the EPA approved the majority of Utah’s RH SIP, but disapproved the BART 

determination for nitrogen oxide (NOx) and particulate matter (PM). Utah is in the process of updating 

the five-factor analysis to address EPA’s concerns. The results of that analysis will be addressed in a 

separate SIP submittal. The 2008 BART determination has been fully implemented and significant 

emission reductions of NOx, SO2, and PM have already been achieved.

1.1 State Implementation Plan Requirements for the 5-Year Progress Report

Provisions of the Regional Haze (RH) rule contained in 40 CFR §51.309(d)(10) require that each state 

submit a progress report five years after the submittal of their initial RH SIP. The progress report must be 

in the form of a SIP revision and must include a determination regarding the adequacy of the existing 

regional haze SIP. This report has been prepared to fulfill all applicable requirements pertaining to the 

five-year progress report of the initial RH SIP. The State of Utah concludes that based on the progress 

made over the five year period reviewed, no revisions to the Utah Regional Haze SIP are needed at this 

time.

The progress report SIP must include 1) the status for implementation of control measures included in the 

original regional haze SIP, 2) a summary of emission reductions achieved through the implementation of 

control measures, 3) an assessment of visibility conditions, 4) an analysis of the changes in emission 

pollutants, 5) an assessment of significant changes in emissions that may have limited or impeded 

progress in improving visibility, 6) an assessment of whether the current SIP elements and strategies are 

sufficient to meet reasonable progress goals and 7) a review of the State’s visibility monitoring strategy.

The technical data included in this progress report are from the “Western Regional Air Partnership

Regional Haze Rule Reasonable Progress Summary Report” (Appendix A) developed by the Western 

Regional Air Partnership (WRAP)1 in June of 2013 and the WRAP Technical Support System (TSS). 

The WRAP progress report technical support document (TSD) has been prepared on behalf of the 15 

western state members in the WRAP region. It serves as the technical basis for use by states to develop 

the first of their individual reasonable progress reports for the 116 Federal Class I areas located in the 

western states. Data are presented in this report on a regional, state, and Class I area-specific basis that 

characterize the difference between 2000-2004 baseline conditions and current conditions, represented 

here by the most recent successive 5-year average. The WRAP progress report TSD was focused on the 

first 5-year period, 2005-2009, and therefore the monitoring and emission inventory data reflect that time 

1 The WRAP is a collaborative effort of tribal governments, state governments and various federal agencies representing the 

western states that provides technical and policy tools for the western states and tribes to comply with the EPA’s RH 

regulations. Detailed information regarding WRAP support of air quality management issues for western states is provided on 

the WRAP website, www.wrapair2.org. Data summary descriptions and tools specific to RHR support are available on the 

WRAP Technical Support System website, http://vista.cira.colostate.edu/tss/.

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period. Changes in visibility impairment are characterized using aerosol measurements form the 

IMPROVE network (the primary monitoring network for regional haze, both nationwide and in Utah), 

and the differences between emissions inventory years represent both the baseline and current progress 

period.

As required by 40 CFR §51.308(i), the regional haze SIP must include procedures for continuing 

consultation between the states and federal land managers (FLMs) on the implementation of the visibility 

protection program, including development and review of implementation plan revisions and 5-year 

progress reports, and on the implementation of other programs having the potential to contribute to 

impairment of visibly in any mandatory Federal Class I area within the state. Utah intends to consult with 

federal land as required under 40 CFR §51.308. The state of Utah reaffirms its commitment to participate 

in a regional planning process with Alaska, Arizona, California, Colorado, Idaho, Montana, New Mexico, 

North Dakota, Oregon, South Dakota, Washington, Wyoming, the United States Department of Interior 

(USDI) Fish and Wildlife Services (FWS) and National Park Services (NPS), and the United States 

Department of agriculture (USDA) Forest Service (FS).

Pursuant to the Tribal Authority Rule, any tribe whose lands are within the boundaries of the State of 

Utah has the option to develop a RH Tribal Implementation Plan (TIP) for their lands to assure reasonable 

progress in the five Class I areas in Utah. Accordingly, no provisions of this periodic report shall be 

construed as being applicable to Indian Country.

2.0 UTAH CLASS I AREAS

Utah has five Federal Class I areas within its borders: Arches National Park, Bryce Canyon National Park, 

Canyonlands National Park, Capitol Reef National Park, and Zion National Park. All five of Utah’s 

Federal Class I areas are located on the Colorado Plateau (Figure 2.1). 

Figure 2.1. Map Depicting Federal Class I Areas and Representative IMPROVE Monitors in Utah

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Utah’s Department of Environmental Quality’s (DEQ) Division of Air Quality (DAQ) is responsible for 

developing the RH progress report. This progress report compares the current visibility conditions at each 

of these Class I areas to the 2018 reasonable progress goals to determine if Utah is on track to reach these 

goals. The progress report also reviews the long-term strategy to determine if there have been any 

changes that need to be addressed.

In developing the initial RH SIP, DAQ also considered that emission sources outside of Utah may affect 

the visibility at Utah’s Class I areas, and that emission sources within Utah may affect the visibility at 

Class I areas in neighboring states. Through WRAP, the western states worked together to assess stateby-state contributions to visibility impairment in specific Class I areas, including those in Utah and those 

affected by emissions from Utah. The sources identified in the initial RH SIP either impacting Utah’s 

Class I areas or Class I areas outside Utah will be reviewed as part of this progress report.

2.1 Progress Towards Reasonable Progress Goals (40 CFR §51.309(d)(10(i))

Based on IMPROVE monitoring data, all of Utah’s Class I areas show visibility improvement on the 20% 

least impaired days, while on the 20% most impaired days, three areas (Arches, Canyonlands and Zion 

National Parks) show visibility improvement and two areas (Bryce Canyon and Capitol Reef National 

Parks) do not. The largest contributor to increases at these sites was particulate organic mass which 

was associated with large fire events in July and August of 2009. These increases were offset by 

decreases in ammonium nitrate and ammonium sulfate.

The baseline and current visibility conditions as well as the reasonable progress goals for 2018 for the 

20% worst and 20% best days are displayed in Table 2.1.

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Table 2.1. Utah Class I Area IMPROVE Sites Visibility Conditions for the 20% Most and Least Impaired days –

Including 2010 to 2012.

Class I Area

Baseline

(2000-2004)

(dv)

Current

(2005-2009)

(dv)

(2010-2012)

(dv)

2018

Preliminary 

Reasonable 

Progress Case 

(PRP18a)

(dv)

20% Worst Days

Arches NP (CANY1) 11.2 11.0 10.6 10.9

Bryce Canyon NP (BRCA1) 11.6 11.9 10.0 11.2

Canyonlands NP (CANY1) 11.2 11.0 10.6 10.9

Capitol Reef NP (CAPI1) 10.9 11.3 10.1 10.5

Zion NP (ZICA1) 12.52 12.3 10.83 N/A4

20% Best Days

Arches NP (CANY1) 3.7 2.8 2.8 3.5

Bryce Canyon NP (BRCA1) 2.8 2.1 1.7 2.6

Canyonlands NP (CANY1) 3.7 2.8 2.8 3.5

Capitol Reef NP (CAPI1) 4.1 2.7 2.4 3.9

Zion NP (ZICA1) 5.0 4.3 4.4 (see footnote 2) N/A (see footnote 3)

3.0 REGIONAL HAZE PROGRESS REPORT

The requirements for regional haze progress reports are outlined in 51.309(d)(10)(i). The progress report 

for Section 309 RH SIPs must be in the form of a formal SIP submittal and at a minimum must contain 

the following elements:

3.1 40 CFR § 51.309(D)(10)(i) Progress Report Requirements 

(A) A description of the status of implementation of all measures included in the SIP for achieving 

reasonable progress goals for mandatory Class I Federal areas both within and outside the state.

(B) A summary of the emission reductions achieved throughout the state through implementation of the 

measures described in (A) above.

(C) For each mandatory Class I Federal area within the state, an assessment of the following: the current 

visibility conditions for the most impaired and least impaired days; the difference between current 

visibility conditions for the most impaired and least impaired days and baseline visibility conditions; and 

the change in visibility impairment for the most impaired and least impaired days over the past 5 years.

2 The monitor originally intended to represent Zion National Park was the ZION1 IMPROVE monitor, which began operation in 

2000. In 2003, a second site, ZICA1, was established approximately 19 miles from the original ZION1 monitor. The second site 

was installed in part because elevated ammonium nitrate at the original site was influenced by mobile sources from the 

interstate highway that were not representative of park conditions. Section 6.13.1.1 in the WRAP Report (Appendix A) 

describes how the baseline for the ZICA1 was determined.

3 Includes 2012 data only; there were no results available for 2011 and 2012

4 There is no PRP18a established for the new ZICA1 monitor. The PRP18a was originally established for the original ZIONI 

IMPROVE monitor, which was discontinued on July 29, 2004. 

4

 
(D) An analysis tracking the change over the past 5 years in emissions of pollutants contributing to 

visibility impairment from all sources and activities with the state. Emissions changes should be 

identified by type of source or activity. The analysis must be based on the most recent updated emissions 

inventory, with estimates projected forward as necessary and appropriate, to account for emissions 

changes during the applicable 5-year period.

(E) An assessment of any significant changes in anthropogenic emissions within or outside the state that 

have occurred over the past 5 years that have limited or impeded progress in reducing pollutant emissions 

and improving visibility.

(F) An assessment of whether the current SIP elements and strategies are sufficient to enable the state, or 

other states with mandatory Federal Class I areas affected by emissions from the state, to meet all 

established reasonable progress goals. 

(G) A review of the state’s visibility monitoring strategy and any modifications to the strategy as 

necessary.

In the sections to follow, the Utah DAQ will address the various periodic review requirements as outlined 

above.

3.2 Status of Implementation Control Measures: 40 CFR §51.309(d)(10)(i)(A)

40 CFR §51.309(d)(10)(i)(A) requires “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.”

This section provides a description of the emission reduction measures that were included in the State of 

Utah’s Section 309 RH SIP. A summary of the most significant emission reduction strategies and the 

status of controls is provided below.

Utah has been and continues to be committed to implementing the long-term strategies adopted into the 

state’s Section 309 RH SIP. The implementation status of these emission reduction measures are 

described below.

SO2 Milestone and Backstop Trading Program

As a 309 state, Utah continues to participate in the Regional SO2 Milestone and Backstop Trading 

Program. Utah has been participating in this program since 2003, and in March of 2014, submitted the 

annual Regional SO2 Emissions and Milestone Report for 2012. The report shows that the regional SO2

emissions of 115,115 tons were below the 2012 milestone of 200,722 tons. Further information on 

emissions reductions from this program are summarized in Section 3.3 of this report.

Prevention of Significant Deterioration (PSD); New Source Review (NSR) Permitting; and Visibility

Programs

Utah’s PSD program, promulgated in SIP Section VII and R307-405; NSR permitting program, 

promulgated in SIP Section II and R307-401; and Visibility program, promulgated in SIP Section XVII 

and R307-406 continue to protect Class I area visibility by requiring best available control technology for 

5
new sources and assuring that there is not a significant degradation in visibility at Class I areas due to new 

or modified major sources.

BART

Utah has four BART-eligible sources that are subject to BART. They are PacifiCorp Hunter Units 1 and 

2 and PacifiCorp Huntington Units 1 and 2. 

Utah’s 2008 BART determination for Hunter Units 1 and 2 included conversion of existing electrostatic 

precipitators to pulse jet fabric filter bag-houses; the replacement of existing, first generation low-NOx 

burners with Alstom TSF 2000TM low-NOx firing system and installation of two elevations of separated 

overfire air; and the upgrading of the existing flue gas desulfurization system to >90% sulfur dioxide 

removal. These controls were installed on Hunter Unit 2 in 2011 and Hunter Unit 1 in 2014. Average 

annual emissions decreased by 1,306 tons SO2 and 3,028 tons NOx for these two units between 2001-3 

and 2012-13.

For Huntington Units 1 and 2, the 2008 BART determination included converting existing electrostatic 

precipitators to pulse jet fabric filter bag-houses; the replacement of existing, first generation low-NOx 

firing system and installation of two elevations of separated overfire air; the installation of a new wetlime, flue gas de-sulfurization system at Unit 2 (FGD); and upgrading existing flue gas desulfurization 

system to >90% sulfur dioxide removal at Unit 1. These controls were installed on Huntington Unit 1 in 

2010 and Huntington Unit 2 in 2006. Average annual emissions decreased by 12,344 tons SO2 and 4,324

tons NOx for these two units between 2001-3 and 2012-13.

EPA disapproved Utah’s BART determination for NOx and PM on December 14, 2012, because they 

determined that Utah did not perform an adequate 5-factor analysis as required by 40 CFR Part 51, 

Appendix Y. Utah is addressing EPA’s concerns in a separate SIP submittal concurrent with this progress 

report.

Enhanced Smoke Management Program

The State of Utah has developed The Utah Smoke Management Plan (SMP) which provides operating 

procedures for federal and state agencies that use prescribed fire, wildfire, and wildland fire on federal, 

state and private wildlands in Utah. The SMP includes the program elements listed in 40 CFR 

51.309(d)(6)(i), with the exception of alternatives to fire. The SMP was certified by the EPA on 

November 8, 1999 under EPA’s April 1998 Interim Air Quality Policy on Wildland and Prescribed Fires 

(Policy). The requirements of the SMP were also codified into Utah’s Air Quality Rule R307-204, which

applies to all persons using prescribed fire or wildland fire on land they own or manage, including federal,

state, and private wildlands.

New Source Performance Standards Program

Utah’s New Source Performance Standards (NSPS) rule, R307-210, incorporates the latest version of 40 

CFR Part 60 into Utah’s administrative rules. These technology based standards which apply to specific 

categories of stationary sources, result in significant emissions reductions – 40 CFR Part 60 Subpart JJJJ, 

Standards of Performance for Stationary Spark Ignition Internal Combustion Engines; and Subpart IIII, 

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Standards of performance for Stationary Compression Ignition Internal Combustion Engines, are just two 

examples.

Maximum Achievable Control Technology (MACT) Standards Program

Utah’s administrative rule, R307-214, National Emission Standards for Hazardous Air Pollutants, 

incorporates the latest version of 40 CFR Parts 61 and 63 into Utah’s Air Quality rules. NESHAPs are 

the result of MACT standards, performance-based standards, EPA has developed specific to source 

categories. As with NSPS, these NESHAPS result in significant emissions reductions – 40 CFR Part 63 

Subpart ZZZZ, Standards for Reciprocating Internal Combustion Engines, is just one example. 

Mobile Sources

The adoption of new on-road vehicle emission and fuel standards by EPA resulted in a substantial 

reduction of projected mobile source emissions. As stated in Section F.2.b of the SIP, Utah is committed 

to monitoring the emissions from mobile sources to assure a continuous decline in emissions as defined in 

40 CFR 51.309(b)(6). If Utah determines that a continuous decline in emissions is not being achieved, 

additional control measures will be reviewed to determine if they are needed to make reasonable progress. 

Enforceability of Utah’s Measures

40 CFR §51.309(d)(9) of the RH rule requires states to ensure that emission limitations and control 

measures used to meet reasonable progress goals are enforceable.

Utah has ensured that all existing emission limitations and control measures for which it is responsible

that were used to meet reasonable progress goals are enforceable, either through Utah’s Administrative 

Rules or SIP measures previously approved by the Utah Air Quality Board and the EPA. Enforceability 

of future emission limitations and control measures for which the State is responsible will be enforceable 

through permit conditions or SIP measures to be approved in the future by EPA.

3.3 Summary of Emission Reduction Achieved: 40 CFR § 51.309(d)(10)(i)(B)

40 CFR § 51.309(d)(10)(i)(B) requires “a summary of the emissions reductions achieved throughout the 

State through implementation of the measures in paragraph (g)(1).”

This section provides a summary of emissions reduced as a result of implementation measures discussed 

in Section 3.2. Since the submittal of Utah’s Section 309 SIP in 2003, there has been a significant 

decrease in SO2 emissions in accordance with the state’s SO2 Milestone and Backstop Trading Program. 

Each year since 2003, states have been able to demonstrate through milestone reports that actual SO2

emissions have declined every year and are well below the milestones. Sulfur dioxide emission 

reductions associated with the Backstop Trading Program will continue through 2018, as shown through 

declining milestone commitments. The actual emissions and their respective milestones are shown below:

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Regional Sulfur Dioxide Emissions and Milestone Report Summary

Year 3-State Adjusted SO2

Emissions (tons)

3-Year Average 

(tons)

Milestone

(tons)

2003 214,780 214,780 303,264

2004 232,388 223,584 303,264

2005 215,793 220,987 303,264

2006 207,316 218,499 303,264

2007 187,599 203,569 303,264

2008 165,595 186,837 269,083

2009 143,704 165,633 234,903

2010 131,124 146,808 200,722

2011 117,976 130,935 200,722

2012 96,246 115,115 200,722

While Utah has not quantified the emissions reductions due to the remaining strategies, the state saw an 

overall improvement in visibility at all of Utah’s Class I areas for the 20% best days and an overall 

improvement in visibility at three of Utah’s Class I areas for the 20% worst days between 2000 and 2009 

(See Figures 3.1 and 3.2). Changes in the overall emission inventory are described in section 3.5 of this 

report.

Figure 3.1. Change in Deciview Extinction between Baseline Period Average (2000-2004) and the First 

Progress Period Average (2005-2009) for the 20% Worst Visibility Days

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Figure 3.2. Change in Deciview Extinction between Baseline Period Average (2000-2004) and the First 

Progress Period Average (2005-2009) for the 20% Best Visibility Days

The RH rule haze index, as defined using deciview units, does not provide information regarding the 

relative contributions of specific pollutants to overall visibility impairment. The calculation of visibility 

impairment is based on the cumulative impacts of several different species measures at IMPROVE

network sites. Analyzing the behavior of each individual species has important implications for control 

measures, as some species originate from largely anthropogenic sources while others may originate form 

a mixture of both anthropogenic and natural sources. 

Figures 3.3 and 3.4 present regional maps of average aerosol extinction for the most impaired days during 

the baseline period (2000-2004), and the first progress period average (2005-2009), respectively, for the 

IMPROVE monitors representing Federal Class I areas in the WRAP region. The size of the pie chart is 

related to the magnitude of visibility impairment, and colors represent the relative contribution of the 

pollutants measured by the IMPROVE network.

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Figure 3.3. Regional Average of Aerosol Extinction by Pollutant for Baseline Period average (2000-2004) 

for 20% Worst Days.

Figure 3.4. Regional Average of Aerosol Extinction by Pollutant for the First Progress Period Average 

(2005-2009) for 20% Worst Days.

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Figure 3.5 presents the individual species of haze that have decreased between the 2000-2004 baseline 

period and the 2005-2009 progress period, where sites with corresponding decreases in deciview 

measurements are highlighted with blue circles.

For Utah, Figure 3.5 depicts most of the decreases in deciview averages that were associated with 

decreases in ammonium nitrate, ammonium sulfate, coarse mass and particulate organic mass. The 

decrease in ammonium nitrate and ammonium sulfate is most likely due to the implementation of the SO2

milestones beginning in 2003, BART controls beginning at the end of 2006 and federal mobile source 

regulations. The decrease in coarse mass and particulate organic mass is likely due to the decreasing 

effect of natural events, such as windblown dust storms and wild fires. 

Figure 3.5. Magnitude of Aerosol Extinction Species that have Decreased Between the Baseline Average 

(2000-2004) and the First Progress Period Average (2005-2009) for the 20% Worst Days.

3.4 Assessment of Visibility Conditions: 40 CFR § 51.309(d)(10)(i)(C)

40 CFR § 51.309(d)(10)(i)(C) requires “for each mandatory Class I Federal area within the State, the 

State must assess the following visibility conditions and changes, with values for most impaired and least 

impaired days expressed in terms of 5-year averages of these annual values

The current visibility conditions for the most impaired and least impaired days;

The difference between current visibility conditions for the most impaired and least days and baseline 

visibility conditions;

The changes in visibility impairment for the most impaired and least impaired days over the past 5-

years.”

11
This section addresses RH rule regulatory requirements for monitored data as measured by IMPROVE 

monitors representing Federal Class I areas in Utah.

Regional haze progress in Federal Class I areas is tracked using calculations based on speciated aerosol 

mass as collected by IMPROVE monitors. The RH rule calls for tracking haze in units of deciviews, 

where the deciview metric was designed to be linearly associated with human perception of visibility. In

a pristine atmosphere, the deciview metric is near zero, and a one deciview change is approximately 

equivalent to a 10% change in cumulative species extinction. To better understand visibility conditions, 

summaries here include both the deciview metric and the apportionment of haze into extinction due to the 

various measured species in units of inverse megameters (Mm-1

).

3.4.1 Current Visibility Conditions for the Most and Least Impaired Days

EPA guidance for the 2003 RH SIP specifies that 5-year averages be calculated over successive 5-year 

periods; i.e., 2000-2004, 2005-2009, 2010-2014, etc.5

 Current visibility conditions are represented in 

Table 3.1 and 3.2 as the most recently incorporated successive 5-year average period available, the 2005-

2009 period average. While the most recent IMPROVE monitoring data currently available in the WRAP 

TSS includes 2012 data, the 2005-2009 period was the most recent data set available when the WRAP 

summary report was generated. The information and data presented in this section are from that “Western 

Regional Air Partnership Regional Haze Rule Reasonable Progress Summary Report” (Appendix A).

Tables 3.1 and 3.2 present the calculated deciview values for current conditions at each site, along with 

the percent contribution to extinction from each aerosol species for the 20% worst and best days for each 

of the Federal Class I area IMPROVE monitors in Utah. Appendix M of the WRAP Progress Report 

includes figures that represent the annual and 5-year period averages for the 20% most and least impaired 

visibility days at each IMPROVE site from 2000 to 2010.

Figure 3.6 presents 5-year average extinction for the current progress period for both the 20% worst and 

best days. Note that the percentages in the tables consider only the aerosol species which contribute to 

extinction, while the charts also show Rayleigh, or scattering due to background gases in the atmosphere. 

Specific observations for the current visibility conditions on the 20% most impaired days are as follows:

• The largest contributors to aerosol extinction at Utah sites were particulate organic mass,

ammonium sulfate and coarse mass.

• The highest aerosol extinction (12.3 dv) was measured at the ZICA1 site, where particulate 

organic mass was the largest contributor to aerosol extinction, followed by coarse mass. 

• The lowest aerosol extinction (11.0 dv) was measured at the CANY1 site.

Specific observations for the current visibility conditions on the 20% least impaired days are as follows:

• The aerosol contribution to total extinction on the beset days was less than Rayleigh, or the 

background scattering that would occur in clean air. 

• Average extinction (including Rayleigh) ranged from 2.1 dv (BRCA2) to 4.3 dv (ZICA1).

5 EPA’s September 2003 Guidance for Tracking Progress Under the Regional Haze Rule specifies that progress is 

tracked against the 2000-2004 baseline period using corresponding averages over successive 5-year periods; i.e., 

2005-2009, 2010-2014, etc. (see page 4-2 in the Guidance document).

12

 
• For all sites, ammonium sulfate was the largest contributor to the non-Rayleigh aerosol species of 

extinction.

Table 3.1, Utah Class I Area IMPROVE Sites 

Current Visibility Conditions, 2005-2009 Progress Period, 

20% Most Impaired Days

Table 3.2, Utah Class I Area IMPROVE Sites

Current Visibility Conditions, 2005-2009 Progress Period,

20% Least Impaired Days

13
Figure 3.6. Average Extinction for Current Progress Period (2005-2009) for the Worst (Most Impaired) 

and Best (Least Impaired) Days Measured at Utah Class I Area IMPROVE Sites

3.4.2 Differences Between Current Visibility Conditions for the Most and Least 

Impaired Days and Baseline Visibility Conditions

Included here are comparisons between the 5-year average baseline conditions (2000-2004) and the 

current progress period extinction (2005-2009).

Table 3.3 presents the differences between the 2000-2004 baseline period average extinction and the 

2005-2009 progress period average for each site in Utah for the 20% most impaired days, and Table 3.4 

presents similar data for the least impaired days. Averages that increased are depicted in red text, and 

averages that decreased are depicted in blue.

Figure 3.7 presents the differences in the 5-year average extinction for the baseline and current progress 

period average for the worst days and Figure 3.8 presents the differences in averages by aerosol species, 

with increases represented above the zero line and decreases below the zero line. Figures 3.9 and 3.10 

present similar plots for the best days.

For the 20% most impaired days, the 5-year average Regional Haze Rule (RHR) deciview metric 

increased between the 2000-2004 and 2005-2009 periods at the BRCA1 and CAPI1 sites and decreased at 

the CANY1 and ZICA1 sites. Notable differences for individual species averages were as follows:

Increases in 5-year average deciviews at the BRCA1 and CAPI1 sites were mostly due to increases in 

particulate organic mass, with some increases also measured in elemental carbon and soil. Coarse mass 

also contributed to increases at the CAPI1 site. Increases were offset by decreases in ammonium nitrate 

and ammonium sulfate at both sites.

14
Ammonium sulfate decreased at all sites except ZICA1. Note that data was not collected at the ZICA site

during the baseline years, and changes reported here are proportional to average changes in extinction as 

measured at regional sites.

Increases in ammonium nitrate at CANY1 may be due to decreases in SO2 emissions that reduce the 

formation of ammonium sulfate and therefore result in an increase in ammonium nitrate in ammonia 

limited conditions.

For the 20% least impaired days, the 5-year average deciview metric decreased at all sites. Notable 

differences for individual species averages on the 20% least impaired days were as follows:

All species at all sites either decreased or stayed the same between the baseline and current progress 

period for the best days. The largest decreases on the best days were measured in particulate organic 

mass, ammonium nitrate, ammonium sulfate, and coarse mass.

Table 3.3. Utah Class I Area IMPROVE Sites 

Difference in Aerosol Extinction by Species, 2000-2004 Baseline Period to 2005-2009 Progress Period

Table 3.4. Utah Class I Area IMPROVE Sites

Difference in Aerosol Extinction by Species, 2000-2004 Baseline Period to 2005-2009 Progress Period

20% Least Impaired Days

Site

Deciview (dv) Change in Extinction by Species (Mm-1

)*

2000-04

Baseline

Period

2005-09

Progress

Period

Change

in dv*

Amm.

Sulfate

Amm.

Nitrate POM EC Soil CM SeaSalt

BRCA1 2.8 2.1 -0.7 -0.1 -0.2 -0.3 -0.2 0.0 -0.1 0.0

CANY1 3.7 2.8 -0.9 -0.3 -0.1 -0.5 -0.1 -0.1 -0.2 0.0

CAPI1 4.1 2.7 -1.4 -0.3 -0.4 -0.5 -0.3 -0.1 -0.4 0.0

ZICA1 5.0 4.3 -0.7 -0.1 -0.2 -0.5 -0.2 0.0 -0.1 0.0

*Change is calculated as progress period average minus baseline period average. Values in red indicate increases in

extinction and values in blue indicate decreases.

15
Figure 3.7. Average Extinction for Baseline and Progress Period Extinction for Worst (Most Impaired) Days 

Measured at Utah Class I Area IMPROVE Sites.

Figure 3.8. Difference between Average Extinction for Current Progress Period (2005-2009) and Baseline 

Period (2000-2004) for the Worst (Most Impaired) Days Measured at Utah Class I Area IMPROVE Sites.

16
Figure 3.9. Average Extinction for Baseline and Progress Period Extinction for Best (Least Impaired) Days 

Measured at Utah Class I Area IMPROVE Sites

Figure 3.10. Difference Between Average Extinction for Current Progress Period (2005-2009) and Baseline 

Period (2000-2004) for the Best (Least Impaired) Days Measured at Utah Class I Area IMPROVE Sites

17
3.4.3 Change in Visibility Impairment for the Most Impaired and Least Impaired Days 

Over the Past Five Years

Included here are changes in visibility impairment as characterized by annual average trend statistics and 

some general observations regarding local and regional events and outliers on a daily and annual basis 

that affected the current 5-year progress period. The regulatory requirement asks for a description of 

changes over the past 5-year progress period, but trend analysis is better suited to longer periods of time, 

so trends for the entire 10-year planning period are presented here.

Trend statistics for the years 2000-2009 for each species at each site in Utah are summarized in Table 

3.56

. Only trends for aerosol species trends with p-value statistics less than 0.15 (85% confidence level) 

are presented in the table here, with increasing slopes in red and decreasing slopes in blue7

. In some 

cases, trends may show decreasing tendencies while the difference between the 5-year averages do not (or 

vice versa). In these cases, the 5-year average for the best and worst days is the important metric for the 

RHR regulatory purposes, but trend statistics may be of value to understand and address visibility 

impairment issues for planning purposes. 

For each site, a more comprehensive list of all trends for all species, including the associated p-values, is 

provided in Appendix M of the Western Regional Air Partnership Regional Haze Rule Reasonable 

Progress Summary Report. Additionally, the appendix includes plots depicting 5-year, annual, monthly 

and daily average extinction for each site. Some general observations regarding changes in visibility 

impairment at sites in Utah are as follows:

• Particulate organic mass was the largest contributor to aerosol extinction at all sits in Utah. The 

largest difference between the 5-year average baseline and progress periods was measured for 

particulate organic mass at the BRCA1 site. This difference average was influenced by high 

particulate organic mass events in July and August, 2009.

• For ammonium sulfate, annual average trend statistics for all measured days indicated decreasing 

trends at all Utah sites. A slight increase in the 5-year average ammonium sulfate was reported 

for the ZICA1 site, but this was based on a baseline average estimate (Section 6.13.1.1 of 

Appendix M of the WRAP Report). Actual data measured between 2004 and 2009 at the ZICA1 

site indicated a slightly decreasing annual average trend.

6 Annual trends were calculated for the years 2000-2009, with a trend defined as the slope derived using Theil statistics. Trends 

derived from Theil statistics are useful in analyzing changes in air quality data because these statistics can show the overall 

tendency of measurements over long periods of time, while minimizing the effects of year-to-year fluctuations which are 

common in air quality data. Theil statistics are also used in EPA’s National Air EPA’s National Air Quality Trends Reports 

(http://www.epa.gov/airtrends/) and the IMPROVE program trend reports 

(http://vista.cira.colostate.edu/improve/Publications/improve_reports.htm)

7 The significance of the trend is represented with p-values calculated using Mann-Kendall trend statistics. Determining a 

significance level helps to distinguish random variability in data from a real tendency to increase or decrease over time, where 

lower p-values indicate higher confidence levels in the computed slopes.

18

 
• For ammonium nitrate, annual average trend statistics for all measured days indicated a 

decreasing trend at the CAPI1 site and either no trend or insignificant trends at the other Utah 

sites.

• For soil, slightly increasing annual average tends were measured at the ZICA1 site and an 

increasing trend for the worst days was measured at the CAPI1 site.

• Coarse mass increased at the CAPI1 and CANY1 sites, but these sites did not show increasing 

trends. Higher 5-year current period averages were influenced by higher than average coarse 

mass events in late April of 2008 at both sites.

Table 3.5. Utah Class I Area IMPROVE Sites

Change in Aerosol Extinction by Species

200-2009 Annual Average Trends

3.5 Analysis of Emissions: 40 CFR 40 CFR § 51.309(d)(10)(i)(D)

40 CFR §51.309(d)(10(i)(D) requires “An analysis tracking the change over the past 5 years in emissions 

of pollutants contributing to visibility impairment from all sources and activities within the State. 

Emissions changes should be identified by type of source or activity. The analysis must be based on the 

most recent updated emissions inventory, with estimates projected forward as necessary and appropriate, 

to account for emissions changes during the applicable 5-year period.”

Included here are summaries depicting differences between two emission inventory years that are used to 

represent the 5-year baseline and current progress periods. The baseline period is represented using a 

2002 inventory developed by the WRAP for use in the initial WRAP state SIPs, and the progress period is 

represented by a 2008 inventory which leverages recent WRAP inventory work for modeling efforts. For 

reference, Table 3.6 lists the pollutants inventoried, the related aerosol species, some of the key sources 

for each pollutant, and some notes regarding implications of these pollutants. Differences between these 

19
baseline and progress period inventories, and a separate summary of annual emissions from electrical 

generating units (EGUs), are presented in this section.

Table 3.6

Utah

Pollutants, Aerosol Species, and Major Sources

Emitted

Pollutant

Related

Aerosol Major Sources Notes

Sulfur

Dioxide

(SO2)

Ammonium

Sulfate

Point Sources;

On- and OffRoad Mobile

Sources

SO2 emissions are generally associated with anthropogenic

sources such as coal-burning power plants, other industrial

sources such as refineries and cement plants, and both on- and

off-road diesel engines.

Oxides of

Nitrogen

(NOX)

Ammonium

Nitrate

On- and OffRoad Mobile

Sources;

Point Sources;

Area Sources

NOX emissions are generally associated with anthropogenic

sources. Common sources include virtually all combustion

activities, especially those involving cars, trucks, power plants,

and other industrial processes.

Ammonia

(NH3)

Ammonium

Sulfate

and

Ammonium

Nitrate

Area Sources;

On-Road

Mobile Sources

Gaseous NH3 has implications in particle formation because it

can form particulate ammonium. Ammonium is not generally 

directly measured by the IMPROVE program, but affects

formation potential of ammonium sulfate and ammonium

nitrate. All measured nitrate and sulfate is assumed to be

associated with ammonium for IMPROVE reporting purposes.

Volatile

Organic

Compounds

(VOCs)

Particulate

Organic

Mass

(POM)

Biogenic

Emissions;

Vehicle

Emissions;

Area Sources

VOCs are gaseous emissions of carbon compounds, which are

often converted to POM through chemical reactions in the

atmosphere.

Estimates for biogenic emissions of VOCs have undergone

significant updates since 2002, so changes reported here are more

reflective of methodology changes than actual changes in

emissions (see Section 3.2.1).

Primary POM Wildfires; POA represents organic aerosols that are emitted directly as

Organic Area Sources particles, as opposed to gases. Wildfires in the west generally

Aerosol dominate POA emissions, and large wildfire events are generally

(POA) sporadic and highly variable from year-to-year.

Elemental EC Wildfires; Large EC events are often associated with large POM events

Carbon On- and Off- during wildfires. Other sources include both on- and off-road

(EC) Road Mobile diesel engines.

Sources

Fine Soil Soil Windblown

Dust;

Fugitive Dust;

Road Dust;

Area Sources

Fine soil is reported here as the crustal or soil components of

PM2.5.

Coarse

Mass

(PMC)

Coarse

Mass

Windblown

Dust;

Fugitive Dust

Coarse mass is reported by the IMPROVE Network as the

difference between PM10 and PM2.5 mass measurements. Coarse

mass is not separated by species in the same way that PM2.5 is

speciated, but these measurements are generally associated with

crustal components. Similar to crustal PM2.5, natural windblown

dust is often the largest contributor to PMC.

20
For these summaries, emissions during the baseline years are represented using a 2002 inventory, which 

was developed with support from the WRAP for use in the original RH SIP strategy development (termed 

plan02d). Differences between inventories are represented as the difference between the 2002 inventory 

and a 2008 inventory which leverages recent inventory development work performed by the WRAP for 

the West-wide Jumpstart Air Quality Modeling Study (WestJumpAQMS) and Deterministic & Empirical 

Assessment of Smoke's contribution to Ozone (DEASCO3) modeling projects (termed WestJump2009). 

Note that the comparison of differences between inventories does not necessarily reflect a change in

emissions, as a number of methodology changes and enhancements have occurred between development 

of the individual inventories (See Appendix A). Inventories for all major visibility impairing pollutants 

are presented for major source categories, and categorized as either anthropogenic or natural emissions.

Table 3.7 and Figure 3.11 present the differences between the 2002 and 2008 sulfur dioxide (SO2) 

inventories by source category. Table 3.8 and Figure 3.11 present data for oxides of nitrogen (NOx), and

Tales 3.9 through 3.14 and Figures 3.12 through 3.18 present data for ammonia (NH3), volatile organic 

compounds (VOCs), primary organic aerosol (POA), elemental carbon (EC), fine soil, and coarse mass. 

General observations regarding emissions inventory comparisons are listed below.

• The largest differences for point source inventories were a decrease in SO2 emissions and an 

increase in NOX. 

• Area source inventories showed decreases in SO2 and increases in NOX, NH3, POA, and VOCs. 

These changes may be due to a combination of population changes and differences in 

methodologies used to estimate these emissions (see Section 3.2.1 of Appendix A). One 

methodology change was the reclassification of some off-road mobile sources (such as some 

types of marine vessels and locomotives) into the area source category in 2008, which may have 

contributed to increases in area source inventory totals, but decreases in off-road mobile totals. 

• On-road mobile source inventory comparisons showed decreases in most parameters, especially 

NOX and VOCs, with increases in POA, EC, and coarse mass. Reductions in NOX and VOC are 

likely influenced by federal and state emissions standards that have already been implemented. 

The increases in POA, EC, and coarse mass occurred in all of the WRAP states for on-road 

mobile inventories, regardless of reductions in NOX and VOCs, indicating that these increases 

were likely due use of different on-road models, as referenced in Section 3.2.1 of Appendix A. 

• Off-road mobile source inventories showed decreases in NOx, SO2, and VOCs, and increases in 

fine soil and coarse mass, which was consistent with most contiguous WRAP states. These 

differences were likely due to a combination of actual changes in source contributions and 

methodology differences, as referenced in Section 3.2.1 of Appendix A. As noted previously, one 

major methodology difference was the reclassification of some off-road mobile sources (such as 

some types of marine vessels and locomotives) into the area source category in 2008, which may 

have contributed to decreases in the off-road inventory totals, but increases in area source totals. 

• Inventory comparison results for area oil and gas showed an increase in NOX and a decrease in 

VOCs. Note that inventory methodologies for these sources may have evolved substantially 

between the baseline and 2008 inventories as referenced in Section 3.2.1. Also, WRAP Phase III 

oil and gas inventories are reported here for entire basins, and include oil and gas emissions 

within tribal boundaries.

21
• For most parameters, especially POAs, VOCs, and EC, fire emission inventory estimates 

decreased. Note that these differences are not necessarily reflective of changes in monitored data, 

as the baseline period is represented by an average of 2000-2004 fire emissions, and the progress 

period is represented only by the fires that occurred in 2008, as referenced in Section 3.2.1 of 

Appendix A.

• Comparisons between VOC inventories showed large decreases in biogenic emissions, which was 

consistent with other contiguous WRAP states. Estimates for biogenic emissions of VOCs have 

undergone significant updates since 2002, so changes reported here are more reflective of 

methodology changes than actual changes in emissions, as referenced in Section 3.2.1 of 

Appendix A.

• Fine soil and coarse mass increased for the windblown dust inventory comparisons and the 

combined fugitive/road dust inventories. Large variability in changes in windblown dust was 

observed for the contiguous WRAP states, which was likely due in large part to enhancements in 

dust inventory methodology rather than in changes in actual emissions.

22
Table 3.7

Sulfur Dioxide Emissions by Category

Figure 3.11. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for Sulfur 

Dioxide by Source Category for Utah

23
Table 3.8

Oxides of Nitrogen Emissions by Category

Oxides of Nitrogen Emissions (tons/year)

Source Category 2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 84,218 87,623 3,405

Area 6,146 17,269 11,124

On-Road Mobile 77,381 64,186 -13,195

Off-Road Mobile 47,100 13,249 -33,851

Area Oil and Gas 3,335 4,136 801

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 319 65 -254

Total Anthropogenic 218,499 186,528 -31,971 (-15%)

Natural Sources

Natural Fire 8,873 650 -8,223

Biogenic 12,597 6,144 -6,453

Wind Blown Dust 0 0 0

Total Natural 21,470 6,793 -14,676 (-68%)

All Sources

Total Emissions 239,969 193,322 -46,647 (-19%)

Figure 3.12. 2002 and 2008 Emissions and Difference between Emissions Inventory Totals, for Oxides of 

Nitrogen by Source Category for Utah

24
Table 3.9

Ammonia Emissions by Category

Ammonia Emissions(tons/year)

Source Category 2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 1,905 556 -1,349

Area 23,642 37,639 13,997

On-Road Mobile 2,453 1,048 -1,405

Off-Road Mobile 32 16 -16

Area Oil and Gas 0 0 0

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 75 37 -38

Total Anthropogenic 28,107 39,295 11,189 (40%)

Natural Sources

Natural Fire 1,893 449 -1,444

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 1,893 449 -1,444 (-76%)

All Sources

Total Emissions 29,999 39,744 9,744 (32%)

Figure 3.13. 2002-2008 Emission and Difference between Emission Inventory Totals, for Ammonia by 

Source Category for Utah

25
Table 3.10

Volatile Organic Compound Emissions by Category

Source Category Volatile Organic Compound Emissions(tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 7,367 9,285 1,919

Area 46,679 72,811 26,132

On-Road Mobile 49,075 27,138 -21,937

Off-Road Mobile 26,933 23,213 -3,720

Area Oil and Gas 35,961 25,358 -10,603

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 536 126 -410

Total Anthropogenic 166,550 157,931 -8,619 (-5%)

Natural Sources

Natural Fire 19,484 720 -18,764

Biogenic 641,481 237,799 -403,682

Wind Blown Dust 0 0 0

Total Natural 660,965 238,518 -422,446 (-64%)

All Sources

Total Emissions 827,515 396,449 -431,065 (-52%)

Figure 3.14. 2002-2008 Emission and Difference between Emission Inventory Totals, for Volatile Organic 

Compounds by Source Category for Utah

26
Table 3.11

Primary Organic Aerosol Emissions by Category

Source Category Primary Organic Aerosol Emissions (tons/year)

2002 (Plan02d) 2008 (WestJump2008) Difference (Percent Change)

Anthropogenic Sources

Point* 392 75 -317

Area 578 3,045 2,468

On-Road Mobile 637 1,573 937

Off-Road Mobile 965 666 -299

Area Oil and Gas 0 28 28

Fugitive and Road Dust 141 886 745

Anthropogenic Fire 507 106 -401

Total Anthropogenic 3,219 6,380 3,161 (98%)

Natural Sources

Natural Fire 26,187 1,167 -25,020

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 26,187 1,167 -25,020 (-96%)

All Sources

Total Emissions 29,407 7,547 -21,859 (-74%)

Figure 3.15. 2002-2008 Emission and Difference between Emission Inventory Totals, for Primary Organic 

Aerosol by Source Category for Utah

27
Table 3.12

Elemental Carbon Emissions by Category

Elemental Carbon Emissions (tons/year)

Source Category 2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point* 102 24 -77

Area 12 513 500

On-Road Mobile 663 2,593 1,930

Off-Road Mobile 2,492 715 -1,777

Area Oil and Gas 0 0 0

Fugitive and Road Dust 11 21 11

Anthropogenic Fire 85 23 -62

Total Anthropogenic 3,364 3,889 525 (16%)

Natural Sources

Natural Fire 5,405 209 -5,196

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 5,405 209 -5,196 (-96%)

All Sources

Total Emissions 8,769 4,098 -4,671 (-53%)

Figure 3.16. 2002-2008 Emission and Difference between Emission Inventory Totals, for Elemental Carbon 

by Source Category for Utah

28
Table 3.13

Fine Soil Emissions by Category

Fine Soil Emissions (tons/year)

Source Category 2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point* 2,933 712 -2,222

Area 160 1,595 1,435

On-Road Mobile 426 257 -170

Off-Road Mobile 0 47 47

Area Oil and Gas 0 479 479

Fugitive and Road Dust 2,411 14,164 11,753

Anthropogenic Fire 81 43 -38

Total Anthropogenic 6,011 17,296 11,285 (>100%)

Natural Sources

Natural Fire 1,719 429 -1,290

Biogenic 0 0 0

Wind Blown Dust 7,573 10,810 3,237

Total Natural 9,292 11,239 1,948 (21%)

All Sources

Total Emissions 15,302 28,535 13,232 (86%)

Figure 3.17. 2002-2008 Emission and Difference between Emission Inventory Totals, for Fine Soil by 

Source Category for Utah

29
Table 3.14

Coarse Mass Emissions by Category

Coarse Mass Emissions (tons/year)

Source Category 2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point* 8,442 4,216 -4,226

Area 2,387 2,017 -371

On-Road Mobile 414 2,801 2,387

Off-Road Mobile 0 76 76

Area Oil and Gas 0 12 12

Fugitive and Road Dust 12,374 107,079 94,705

Anthropogenic Fire 59 20 -39

Total Anthropogenic 23,677 116,221 92,544 (>100%)

Natural Sources

Natural Fire 5,671 224 -5,448

Biogenic 0 0 0

Wind Blown Dust 68,153 97,289 29,136

Total Natural 73,824 97,513 23,689 (32%)

All Sources

Total Emissions 97,501 213,733 116,233 (>100%)

Figure 3.18. 2002-2008 Emission and Difference between Emission Inventory Totals, for Coarse Mass by 

Source Category for Utah

30
As described above, differences between the baseline and progress period inventories presented here do 

not necessarily represent changes in actual emissions because numerous updates in inventory 

methodologies have occurred between the development of the separate inventories. Also, the 2002 

baseline and 2008 progress period inventories represent only annual snapshots of emissions estimates, 

which may not be representative of the entire 5-year monitoring periods compared. To better account for 

year-to-year changes in emissions, annual emissions totals for Utah electrical generating units (EGUs) are 

presented here. EGU emissions are some of the more consistently reported emissions, as tracked in 

EPA’s Air Markets Program Database for permitted Title V facilities in the state 

(http://ampd.epa.gov/ampd). RHR implementation plans are required to pay specific attention to certain 

major stationary sources, including EGUs, built between 1962 and 1977. 

Figure 3.19 presents a sum of annual NOx and SO2 emissions as reported for Utah EGU sources between 

1996 and 2010. While these types of facilities are targeted for controls in state regional haze SIPs, it 

should be noted that many of the controls planned for EGUs in the WRAP states had not taken place yet 

in 2010, while other controls separate from the RHR may have been implemented. The chart shows some 

periods of decline for both NOx and SO2, with a sharp decline in SO2 emissions between 2006 and 2007.

Figure 3.19. Sum of EGU Emissions of SO2 and NOx Reported between 1996 and 2010

31
3.6 Changes to Anthropogenic Emissions: § 51.309(d)(10)(i)(E)

40 CFR §51.309(d)(10)(i)(E) requires an assessment of any significant changes in anthropogenic 

emissions within or outside the State that have occurred over the past 5 years that have limited or 

impeded progress in reducing pollutant emissions and improving visibility.”

Table 3.15 displays the average light extinction for the 20% worst days over the 5-year period 2005 

through 2009 for all Class I areas in Utah. The table demonstrates that on the 20% worst days in the 

Class I areas in Utah, particulate organic mass and ammonium sulfate are the major concern for visibility 

impairment. Appendix M includes monitoring data summaries over the 5-year period 2005-2009 for the 

20% worst and best days for each Class I area in Utah. 

Table 3.15. Average extinction for 20% Worst Days for the Current Progress Period of 2005-2009

Site Deciviews

(dv)

Percent Contribution to Aerosol Extinction by Species (Excludes Rayleigh)

(% of Mm-1) and Rank*

Ammonium

Sulfate

Ammonium

Nitrate

Particulate

Organic

Mass

Elemental

Carbon

Soil Coarse

Mass

Sea

Salt

BRCA1 11.9 19% (2) 9% (5) 45% (1) 10% (4) 5% (6) 12% (3) 0% (7)

CANY1 11.0 23% (2) 14% (4) 27% (1) 7% (5) 7% (6) 20% (3) 0% (7)

CAPI1 11.3 24% (2) 12% (4) 32% (1) 8% (5) 7% (6) 17% (3) 0% (7)

ZICA1 12.3 21% (3) 7% (5) 33% (1) 9% (4) 7% (6) 22% (2) 0% (7)

The primary sources of anthropogenic particulate organic mass in Utah include prescribed burning, 

vehicle exhaust, vehicle refueling, solvent evaporation (e.g., paints), food cooking, and various 

commercial and industrial sources. Anthropogenic sources of SO2 include coal-burning power plants and 

other industrial sources, such as boilers, oil refineries and copper smelters. Stationary point sources 

account for approximately 90% of SO2 emissions in Utah.

There do not appear to be any anthropogenic emissions within Utah that would have limited or impeded 

progress in reducing pollutant emissions or improving visibility.

3.7 Assessment of Current SIP Strategy: § 51.309(d)(10)(i)(F)

40 CFR § 51.309(d)(10)(i)(F) requires “an assessment of whether the current implementation plan 

elements and strategies are sufficient to enable the State, or other States with mandatory Federal Class I 

areas affected by emissions from the State, to meet all established reasonable progress goals.”

Figure 3.20 shows the annual and 5-year period averages for the 20% worst days at Canyonlands National 

Park and Arches National Park from 2000 to 2010. This figure demonstrates that on the 20% worst days, 

visibility continues to improve at these Class I areas from the baseline average through the first progress 

period. Similar results are seen for Zion National Park at the ZICA1 monitor (Appendix M). Figures 

3.21 and 3.22 show the annual and 5-year period averages for the 20% worst days at Bryce Canyon 

32
National Park (BRCA1 site) and Capitol Reef Nation Park (CANY1 Site). At both of these monitors, the 

5-year period average from 2005 to 2009 is higher than the baseline. Note that the increase in deciviews 

in 2009 from these monitors is attributed to peak increases of particulate organic mass, which was a result 

of large fire events throughout the region in both July and August of that year. Utah should not be held 

accountable for visibility impairing emissions that are uncontrollable. However, even with wildfire 

emissions included in the assessment, monitoring data shows that visibility continues to improve for both 

the 20% best and worst days through 2010 at all IMPROVE sites (Appendix M).

Figure 3.20. Annual and 5-Year Period Averages for the 20% Worst Days at Canyonlands and Arches 

National Parks (CANY1 IMPROVE Site)

Figure 3.21. Annual and 5-Year Period Averages for the 20% Worst Days at Bryce Canyon National Park 

(BRCA1 IMPROVE Site)

33
Figure 3.22. Annual and 5-Year Period Averages for the 20% Worst Days at Capitol Reef (CAPI1 IMPROVE 

Site)

As table 3.16 shows, Utah is showing improvement in visibility on the most impaired days and no 

degradation on the least impaired days between baseline and current monitoring data. The first 5-year 

progress period evaluated in this report covers the 2005-2009 timeframe, as it represents the most recent 

successive 5-year averaging period; however, the WRAP TSS has been updated to include data up 

through 2012. The average of the first three years of the next successive 5-year progress period (2010-

2014) indicates that visibility at Utah’s Class I areas is improving on both the 20% worst and 20% best 

days. 

34
Table 3.16. Utah Class I Area IMPROVE Sites Visibility conditions – 20% Most and Least Impaired Days Including 

2010 to 2012 data

Class I Area

Baseline

(2000-2004)

(dv)

Current

(2005-2009)

(dv)

(2010-2012)

(dv)

2018

Preliminary 

Reasonable 

Progress Case 

(PRP18a)

(dv)

20% Worst Days

Arches NP (CANY1) 11.2 11.0 10.6 10.9

Bryce Canyon NP (BRCA1) 11.6 11.9 10.0 11.2

Canyonlands NP (CANY1) 11.2 11.0 10.6 10.9

Capitol Reef NP (CAPI1) 10.9 11.3 10.1 10.5

Zion NP (ZICA1) 12.5 12.3 10.88 N/A9

20% Best Days

Arches NP (CANY1) 3.7 2.8 2.8 3.5

Bryce Canyon NP (BRCA1) 2.8 2.1 1.7 2.6

Canyonlands NP (CANY1) 3.7 2.8 2.8 3.5

Capitol Reef NP (CAPI1) 4.1 2.7 2.4 3.9

Zion NP (ZICA1) 5.0 4.3 4.4 (see footnote 7) N/A (see footnote 7)

Utah believes that the current control strategies in the state’s Regional Haze SIP are sufficient to improve 

visibility at Federal Class I areas in the state and to benefit all Class I areas outside of Utah that might be 

impacted by emissions from Utah. 

Northern Utah, which may impact Federal Class I areas in Idaho, Nevada, and Wyoming, is an urban area 

with emissions predominately coming from mobile sources. Mobile NOx emissions in the four main 

urban counties (Weber, Salt Lake, and Utah) are projected to decrease 42,000 tons/yr or 61% between 

2002 and 2018. 

BART controls installed to plants in central Utah (as described in Section 3.2 of this report) are projected 

to decrease SO2 emissions by 13,200 and NOx emissions by 6,200 tons between 2002 and 2018. And as is 

the case with northern Utah, southern Utah has an emissions inventory dominated by mobile sources. In 

Washington County, NOx emissions from mobile sources are projected to decrease 2,300 tons or 57% 

between 2002 and 2018. These emissions reductions benefit Federal Class I areas in Colorado, New 

Mexico and Arizona.

8 Includes 2012 data only; there were no results available for 2010 and 2011. 9 There is no PRP18a established for the new ZICA1 monitor. The PRP18a was originally established for the original ZIONI 

IMPROVE monitor, which was discontinued on July 29, 2004. 

35

 
As stated in Section K of the SIP, oil and gas emissions in eastern Utah are increasing. Approximately 

90% of current emissions from oil and gas development in Uintah and Duchesne Counties occur on land 

that is under the jurisdiction of the Ute Indian Tribe and EPA and is therefore not covered under Utah's 

SIP. For the areas under state jurisdiction, the WRAP Phase III inventory estimated that NOx emissions 

from oil and gas production would increase by about 1,000 tons/yr between 2006 and 2012. Figure 19 in 

Utah's SIP shows the expected impact from Utah sources on Class I areas in western Colorado. While 

NOx emissions from oil and gas production are increasing, mobile source NOx emissions are decreasing 

in the urban area along the Wasatch Front, and NOx emissions are decreasing due to BART in Central 

Utah, showing an overall decreased contribution to nitrate levels in western Colorado. In addition, new 

federal engine standards (NSPS IIII and JJJJ, NESHAP ZZZZ) are leading to additional reductions in 

NOx emissions that will be reflected in future inventories. 

3.8 Assessment of Current Monitoring Strategy: § 51.309(d)(10)(i)(G)

40 CFR § 51.309(d)(10)(i)(G) requires “a review of the State’s visibility monitoring strategy and any 

modifications to the strategy as necessary.”

The primary monitoring network for regional haze, both nationwide and in Utah, is the IMPROVE 

monitoring network. Given that IMPROVE monitoring data from 2000 to 2004 serves as the baseline for 

the regional haze program, the future regional haze monitoring strategy must necessarily be based on, or

directly comparable to the current IMPROVE network. The IMPROVE measurements provide the only 

long-term record available for tracking visibility improvement or degradation; therefore, Utah intends to 

continue reliance on the IMPROVE network for complying with the RH monitoring requirement in the 

RH rule. 

There are currently four IMPROVE sites in Utah (Table 3.17), and no modifications to the existing 

visibility monitoring strategy are necessary at this time.

Table 3.17. Utah CIAs and Representative IMPROVE Monitors

3.9 Determination of Adequacy: § 51.309(d)(10)(ii)

40 CFR § 51.309(d)(10)(ii)(d)(10)(ii) requires “Determination of the adequacy of existing implementation 

plan. At the same time the State is required to submit any 5-year progress report to EPA in accordance 

with paragraph (d)(10)(i) of this section, the State must also take one of the following actions based upon 

the information presented in the progress report:

36
(1) If the State determines that the existing implementation plan requires no further substantive 

revision at this time in order to achieve established goals for visibility improvement and emissions 

reductions, the State must provide to the administrator a negative declaration that further revision of the 

existing implementation plan is not needed at this time.

(2) If the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources in another State(s) which participated in a regional 

planning process, the State must provide notification to the administrator and to the other State(s) which 

participated in the regional planning process with the States. The State must also collaborate with the 

other State(s) through the regional planning process for the purpose of developing additional strategies 

to address the plan’s deficiencies.

(3) Where the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources in another country, the State shall provide 

notification, along with available information, to the Administrator.

(4) Where the State determines that the implementation plan is or may be inadequate to ensure 

reasonable progress due to emissions from sources within the State, the State shall revise its 

implementation plan to address the plan’s deficiencies within one year.”

The State of Utah has provided the information required under 40 CFR § 51.309(d)(10)(ii)(d)(10)(i) in 

this 5-year progress report. Based on this information, the State believes that its current RH SIP is 

adequate to continue to improve visibility in all five Federal Class 1 areas; therefore, a revision to the RH 

SIP is not required. 

4.0 REGIONAL SUMMARY FOR 309 GCVTC CLASS I AREAS

Section 309 rules were based on recommendations from the Grand Canyon Visibility Transport 

Commission (GCVTC) Recommendations report,

10 specific to visibility impacts at the 16 Class I areas on 

the Colorado Plateau. Of the nine western states originally eligible for Section 309 RH rule 

implementation, only the states of New Mexico, Utah, and Wyoming and the city of 

Albuquerque/Bernalillo County currently exercise this option.

The 16 Class I areas on the Colorado Plateau are depicted in Figure 4.1 and listed in Table 4.1. Note that 

the ZION1 site, which originally represented Zion Canyon National Park, has since been replaced with 

the ZICA1 site. This section presents regional progress summaries specific to monitoring and emissions 

data at these Colorado Plateau sites.

10 The Grand Canyon Visibility Transport Commission Recommendations for Improving Western Vistas Report is

archived on the WRAP website at www.wrapair.org/WRAP/reports/GCVTCFinal.PDF.

37

 
Table 4.1

Colorado Plateau Class I Areas and Representative IMPROVE Monitors

38
Figure 4.1. Map Depicting Colorado Plateau Class I Areas and Representative IMPROVE Monitors in 

Arizona, Colorado, New Mexico and Utah

Monitoring Data

Figures 4.2 and 4.3 present the 2005-2009 visibility averages for the 20% worst and best days for the 

IMPROVE sites representing Class I areas on the Colorado Plateau. The size of the pie chart is relative to 

the magnitude of visibility impairment, and colors represent the relative contribution of the pollutants 

which are measured by the IMPROVE network. Tables 4.2 and 4.3 present the difference between the 

2000-2004 baseline period average and the 2005-2009 first progress period average for the 20% worst 

and best days, respectively, for the Class I area sites in the Colorado Plateau region.

39
Table 4.4 presents the differences between the 2000-2004 baseline period average extinction and the 

2005-2009 progress period average for each Class I area site in the Colorado Plateau region for the 20% 

most impaired days, and Table 4.5 presents similar data for the least impaired days. Averages that 

increased are depicted in red text and averages that decreased in blue.

Trend statistics for the years 2000-2009 for each species at each Class I area site in the Colorado Plateau 

region are presented in Table 4.6. Only trends for aerosol species trends with p-value statistics less than 

0.15 (85% confidence level) are presented in the table here, with increasing slopes in red and decreasing 

slopes in blue.

Some general observations for the current visibility conditions and the difference between current and 

baseline conditions are listed below:

• The largest contributors to aerosol extinction at the Colorado Plateau sites were particulate 

organic mass, ammonium sulfate, and coarse mass.

• For all sites, the 5-year average as measured in deciview metric decreased for the best days 

between the baseline and first progress period.

• For most sites, the 5-year average as measured in deciview metric decreased for the worst days 

between the baseline and first progress period. Exceptions included GRCA2 and BALD1 in 

Arizona and BRCA1 and CAPI1 in Utah. Some contributing factors for aerosol measurements 

that affected increased in 5-year average deciviews are listed below.

• The increase at GRCA2 was due to increases in ammonium sulfate, elemental carbon, 

 particulate organic mass and soil, partially offset by decreases in ammonium nitrate and coarse 

 mass. The particulate organic carbon increase was associated with high measurements due to 

 fire events in June and August of 2009. No statistically significant increasing annual trends were 

 measured for any of the species at the GRCA2 site.

• Extinction remained relatively unchanged in terms of deciviews for the worst days measured at 

the BALD1 site. Increases in coarse mass, soil, and ammonium sulfate were offset by decreases 

in particulate organic mass, elemental carbon, and ammonium nitrate. Trend statistics showed an 

increasing coarse mass trend at the BALD1 and PEFO1 sites in eastern Arizona.

• At the BRCA1 and CAPI1 sites, the largest contributor to increases was particulate organic mass 

which, similar to GRCA2, was associated with large fires events in July and August 2009. These 

increases were offset by decreases in ammonium nitrate and ammonium sulfate. An increasing 

soil trend was measured for the worst days at the CAPI1 site.

• Increases in 5-year average ammonium sulfate were measured at many regional sites, although 

most sites showed decreasing annual average ammonium sulfate trends. The 5-year average was 

influenced by relatively high regional measurements of ammonium sulfate in 2005. Figure 5.1.3 

presents a plot of the annual averages for all Colorado Plateau sites, showing the high values 

measured in 2005, followed by generally decreasing trends.

40
Figure 4.2. Regional Average of Aerosol Extinction by Pollutant for the First Progress Period Average 

(2005-2009) for 20% worst days

Figure 4.3. Regional Average of aerosol Extinction by Pollutant for First Progress Period Average (2005-

2009) for 20% Best Days

41
Table 4.2

Colorado Plateau Class I Area IMPROVE Sites

Current Visibility Conditions

2005-2009 Progress Period, 20% Most Impaired Days

42
Table 4.3

Colorado Plateau Class I Area IMPROVE Sites

Current Visibility Conditions

2005-2009 Progress Period, 20% Least Impaired Days

43
Table 4.4

Colorado Plateau Class I Area IMPROVE Sites

Difference in Aerosol Extinction by Species

2000-2004 Baseline Period to 2005-2009 Progress Period

20% Most Impaired Days

44
Table 4.5

Colorado Plateau Class I Area IMPROVE Sites

Difference in Aerosol Extinction by Species

2000-20004 Baseline Period to 2005-2009 Progress Period

20% Least Impaired Days

45
Table 4.6

Colorado Plateau Class I Area IMPROVE Sites

Change in Aerosol Extinction by Species

2000-2009 Annual Average Trends

46
Figure 4.4 Chart Depicting Annual Average Ammonium Sulfate Concentrations for the 20% Worst Days as 

Measured at the Colorado Plateau CIA IMPROVE Sites

Similar to 308 requirements, Section 309 states are required to address how total state emissions have 

changed over the past five years (51.309(d)(10)(i)(D)). Emission inventory summaries using 2002 and 

2008 inventories to represent changes between the baseline and progress periods are described in detail 

for the entire state in Section 3.5.

In addition to tracking these differences in inventories, for the initial SIPs, Section 309 states were 

required to identify “clean air corridors” and track emissions inside and outside of these corridors that 

may affect impairment on the cleanest days.11 In these initial Section 309 SIPs, an area covering major 

portions of Nevada, southern Utah, eastern Oregon and southwestern Idaho was defined as a “clean air 

corridor,” which was intended to represent a region from which clean air transport influences many of the 

clean air days at Grand Canyon National Park. Visibility has improved for the best days at all of the 

Class I area sites on the Colorado Plateau, so emissions specific to the “clean air corridor” counties are 

not presented separately here.

As part of the Western Backstop Sulfur Dioxide Trading Program, the participating states (and county) 

identified SO2 emissions milestones, where a milestone is a maximum level of annual emissions for a 

given year. WRAP supports the Section 309 states with the submittal of annual regional SO2 and 

emission milestone reports which compare actual emissions estimates to the pre-defined milestones.12

Figure 4.5 presents a plot from the most recent SO2 milestone report, showing the 3-year average of 

current emissions through 2012, which indicated that actual emissions were below the SO2 milestone. 

11 Section 51.309(d)(3) states, for treatment of clean-air corridors, “the plan must describe and provide for

implementation of comprehensive emission tracking strategies for clean-air corridors to ensure that the visibility

does not degrade on the least-impaired days at any of the 16 Class I areas.” 12 Annual regional SO2 emissions and milestone reports are located on the WRAP website at

http://www.wrapair2.org/reghaze.aspx.

47

 
Additionally, SO2 emissions specific to EGU sources are presented in Figure 3.19 on an annual basis 

showing changes in these sources between 1996 and 2010 for Utah.

Figure 4.5. Chart Depicting 3-Year Average Sum of SO2 Emissions for New Mexico, Utah and Wyoming and 

the City of Albuquerque/Bernalillo County as Compared to the Section 309 SIP SO2 Milestones

 -

 50,000

 100,000

 150,000

 200,000

 250,000

 300,000

 350,000

2000 2005 2010 2015 2020

tons/yr SO2

SO2 Milestones and Emission Trends

New Mexico, Utah, Wyoming

Three Year Average

Milestone

48