6.0 STATE AND CLASS I AREA SUMMARIES

As described in Section 2.0, each state is required to submit progress reports at interim 

points between submittals of Regional Haze Rule (RHR) State Implementation Plans (SIPs), 

which assess progress towards visibility improvement goals in each state’s mandatory Federal 

Class I areas (CIAs). Data summaries for each CIA in each Western Regional Air Partnership 

(WRAP) state, which address Regional Haze Rule (RHR) requirements for visibility 

measurements and emissions inventories are provided in this section. These summaries are 

intended to provide individual states with the technical information they need to determine if 

current RHR implementation plan elements and strategies are sufficient to meet all established 

reasonable progress goals, as defined in their respective initial RHR implementation plans.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-1
6.13 UTAH

The goal of the RHR is to ensure that visibility on the 20% most impaired, or worst, days 

continues to improve at each Federal Class I area (CIA), and that visibility on the 20% least 

impaired, or best, days does not get worse, as measured at representative Interagency Monitoring 

of Protected Visual Environments (IMPROVE) monitoring sites. Utah has 5 mandatory Federal 

CIAs, which are depicted in Figure 6.13-1 and listed in Table 6.13-1, along with the associated 

IMPROVE monitor locations.

This section addresses differences between the 2000-2004 baseline and 2005-2009 

period, for both monitored data and emission inventory estimates. Monitored data are presented 

for the 20% most impaired, or worst, days and for the 20% least impaired, or best, days, as per 

Regional Haze Rule (RHR) requirements. Annual average trend statistics for the 2000-2009 

10-year period are also presented here to support assessments of changes in each monitored 

species that contributes to visibility impairment. Some of the highlights regarding these 

comparisons are listed below, and more detailed state specific information is provided in 

monitoring and emissions sub-sections that follow.

• For the best days, the 5-year average deciview metric decreased at all Utah Federal 

CIA IMPROVE sites.

• For the worst days, 5-year average deciview metric increased at the BRCA1 and 

CAPI1 sites, and decreased at the ZICA1 and CANY1 sites.

• Changes in deciview averages for the worst days were driven by changes in 

particulate organic mass, which increased at the BRCA1 and CAPI1 sites and 

decreased at the ZICA1 and CANY1 sites.

• Ammonium sulfate decreased at all except the ZICA1 site, but changes in 5-year 

averages at the ZICA1 site used estimates for baseline data that were based on 

changes measured in the broader Colorado Plateau region. Ammonium sulfate 

showed decreasing annual average trends at all sites, which was consistent with 

emissions inventory comparison results that showed large decreases in point source 

SO2 emission inventories.

• Ammonium nitrate decreased at all except the CANY1 site, and showed a statistically 

significant decreasing annual average trend at the CAPI1 site. Changes in emissions 

inventories showed a net reduction in anthropogenic sources, with increases in area 

sources and decreases in mobile sources.

• Coarse mass increased at the CAPI1 and CANY1 sites, but neither site showed

increasing trends. Higher 5-year averages for the current period were influenced by 

higher than average coarse mass events in late April 2008 at both sites.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-2
 

 

Bryce Canyon NP

Arches NP

Canyonlands NP

Capitol Reef NP

 

 

 

 

 

Zion NP

BRCA1

CAPI1 CANY1

ZICA1

Figure 6.13-1. Map Depicting Federal CIAs and Representative IMPROVE Monitors in Utah.

Table 6.13-1

Utah CIAs and Representative IMPROVE Monitors

Class I Area Representative 

IMPROVE Site Latitude Longitude Elevation (m)

Bryce Canyon NP BRCA1 37.62 -112.17 2481

Canyonlands NP CANY1 38.46 -109.82 1798

Arches NP

Capitol Reef NP CAPI1 38.30 -111.29 1896

Zion NP ZICA1* 37.20 -113.15 1215

*Replaced the ZION1 monitoring site in 2003.

6.13.1 Monitoring Data

This section addresses RHR regulatory requirements for monitored data as measured by 

IMPROVE monitors representing Federal CIAs in Utah, including estimates of baseline 

concentrations for the Zion National Park ZICA1 site. These summaries are supported by 

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-3
regional data presented in Section 4.0 and by more detailed site specific tables and charts in 

Appendix M.

As described in Section 3.1, regional haze progress in Federal CIAs is tracked using 

calculations based on speciated aerosol mass as collected by IMPROVE monitors. The RHR 

calls for tracking haze in units of deciviews (dv), 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). 

6.13.1.1 Zion Baseline Estimate

In Utah, the ZION1 IMPROVE monitor, which was originally intended to represent Zion 

National Park, began operation in 2000 at a site located on the northwest edge of the park, near 

an interstate highway. In 2003 a second IMPROVE monitor, ZICA1, was established 

approximately 19 miles from the original ZION1 along the southwest edge of the park. A map

depicting both Zion National Park sites is presented in Figure 6.13-2.

Figure 6.13-2. Map of ZION1 and ZICA1 Sites Representing Zion National Park.

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. Figure 6.13-3 presents a scatter plot of ammonium nitrate measurements for the 

period where both samplers ran concurrently between February 2, 2003, when the ZICA1 

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-4
monitor was installed, and ending July 29, 2004, when monitoring at the ZION1 site was 

discontinued. The comparison indicates that ammonium nitrate measurements were much higher 

at the ZION1 site than the ZICA1 site. Because of these differences, it was determined that 

future RHR SIPs and progress updates should use the ZICA1 data.

y = 0.30x + 0.15

R2 = 0.50

0

2

4

6

8

10

0 2 4 6 8 10

ZICA1 AmmNO3 (μg/m3)

ZION1 AmmNO3 (μg/m3)

ZICA1 vs. ZION1

2/2/2003-7/29/2004

Figure 6.13-3. Correlation Plot for Ammonium Nitrate Depicting Mass Measured at the ZICA1 

and ZION1 sites between February 2, 2003 and July 29, 2004.

RHR guidelines require that progress be measured again the 2000-2004 baseline period,

1

but baseline data are not available for the ZICA1 location. The RHR also states that 

approximations should be made for baseline conditions if these monitoring data are not 

available.

2 A methodology to estimate baseline conditions for the ZICA1 site was developed in 

consultation with the State of Utah – Division of Air Quality and IMPROVE Steering Committee 

representatives from the U.S. Forest Service and National Park Service. This methodology 

involved applying an average of ratios between progress periods and baseline periods at nearby 

sites in the region to scale the ZICA1 progress period. Sites selected included those that represent

the 16 CIAs on the Colorado Plateau, which have previously been treated regionally as the focus 

of the Grand Canyon Visibility Transport Commission (GCVTC) report3 and subsequent Section 

1 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) 2 Section 308(d)(2)(i) of the RHR states, “For mandatory Class I Federal areas without onsite monitoring data for 

2000-2004, the State must establish baseline values using the most representative available monitoring data for 

2000-2004, in consultation with the Administrator or his or her designee.” 3 The June 1996 Grand Canyon Visibility Transport Commission Report, Recommendations for Improving Western 

Vistas Report is available at www.wrapair.org/WRAP/reports/GCVTCFinal.PDF.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-5

 
309 requirements of the RHR. Table 6.13-2 list the Colorado Plateau CIA areas and 

representative IMPROVE sites that were used as the basis for the ZICA1 baseline estimate.

Table 6.13-2

Colorado Plateau CIAs and Representative IMPROVE Sites

State Colorado Plateau

Class I Area

IMPROVE

Site

AZ

Mount Baldy WA BALD1

Grand Canyon NP GRCA2

Petrified Forest NP PEFO1

Sycamore Canyon WA SYCA1

CO

Mesa Verde NP MEVE1

Black Canyon of the Gunnison NP WEMI1 Weminuche WA

Flat Tops WA

Maroon Bells-Snowmass WA WHRI1

West Elk WA

NM San Pedro Parks WA SAPE1

UT

Bryce Canyon NP BRCA1

Arches NP CANY1 Canyonlands NP

Capitol Reef NP CAPI1

Zion NP ZICA1

To estimate baseline conditions at the ZICA1 site, ratios between the 2005-2009 progress 

period and the 2000-2004 baseline period were determined for each species, for both the 20% 

most impaired days and 20% least impaired data, for each site in the Colorado Plateau. The 

average of these ratios was then applied to the ZICA1 progress period measurement to estimate 

the 2000-2004 baseline period for each species at the ZICA1 site, for both the most and least 

impaired days. Table 6.13-3 lists the average progress to baseline period ratios for the Colorado 

Plateau sites for the 20% most impaired days, and Table 6.13-4 lists averages and ratios for the 

least impaired days. These average ratios were applied to the 2005-2009 progress period from 

the ZICA1 site to obtain species and group specific estimates, such that, for each species:

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-6
Table 6.13-3

Colorado Plateau Sites

20% Most Impaired Visibility Days

Species Averages and Ratios

20% Most Impaired 

Days

GRCA1

BALD1

PEFO1

SYCA1

WEMI1

WHRI1

MEVE1

SAPE1

CANY1

BRCA1

CAPI1

Average

Progress/

Baseline 

Ratio

Ammonium 

Sulfate

Baseline 

Period 5.4 6.2 6.6 5.0 5.0 4.8 6.5 5.8 5.6 5.2 5.9

1.04

Progress 

Period 5.8 6.5 7.2 5.7 5.1 5.1 6.3 6.8 5.3 5.0 5.7

Ratio

(progress/

baseline)

1.09 1.04 1.08 1.14 1.02 1.07 0.97 1.17 0.95 0.96 0.97

Ammonium 

Nitrate

Baseline 

Period 2.2 1.1 1.8 2.0 1.2 1.3 2.3 1.6 3.0 2.5 3.4

0.86

Progress 

Period 1.8 1.0 1.5 1.4 1.0 1.3 2.0 1.2 3.3 2.2 2.7

Ratio

(progress/

baseline)

0.81 0.87 0.83 0.67 0.83 1.02 0.86 0.73 1.10 0.89 0.80

Particulate 

Organic 

Carbon

Baseline 

Period 10.7 13.0 10.9 11.7 8.3 7.8 12.3 7.7 7.1 9.4 5.8

0.91

Progress 

Period 10.7 10.9 9.5 11.2 6.9 5.6 6.5 6.3 6.2 11.8 7.6

Ratio

(progress/

baseline)

1.01 0.84 0.87 0.96 0.84 0.71 0.53 0.82 0.87 1.27 1.30

Light 

Absorbing 

Carbon

Baseline 

Period 2.4 2.8 2.9 3.2 2.0 1.8 2.4 1.6 1.7 2.4 1.6

0.98

Progress 

Period 2.9 2.1 3.4 3.5 1.8 1.4 1.6 1.6 1.6 2.5 1.8

Ratio

(progress/

baseline)

1.23 0.75 1.16 1.12 0.92 0.81 0.70 0.96 0.94 1.07 1.09

Soil

Baseline 

Period 1.3 1.1 2.0 6.8 1.3 1.2 2.5 1.5 1.5 1.2 1.3

1.07

Progress 

Period 1.5 1.5 2.6 5.8 1.3 1.3 2.0 1.3 1.5 1.3 1.6

Ratio

(progress/

baseline)

1.11 1.35 1.28 0.85 1.05 1.07 0.79 0.91 1.04 1.06 1.27

Coarse Mass

Baseline 

Period 3.5 2.8 7.3 9.4 3.0 2.8 6.5 2.7 3.8 4.0 3.4

1.00

Progress 

Period 3.2 4.1 6.3 10.8 3.0 2.3 4.6 2.5 4.6 3.1 4.1

Ratio

(progress/

baseline)

0.92 1.44 0.87 1.15 0.99 0.81 0.70 0.93 1.20 0.76 1.20

Sea Salt

Baseline 

Period 0.1 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.1 0.0

2.31

Progress 

Period 0.1 0.1 0.2 0.1 0.0 0.1 0.1 0.1 0.1 0.1 0.1

Ratio

(progress/

baseline)

0.80 2.36 5.36 0.93 0.37 3.05 1.42 0.57 1.80 1.31 7.46

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-7
Table 6.13-4

Colorado Plateau Sites

20% Least Impaired Visibility Days

Species Averages and Ratios

20% Least Impaired 

Days

GRCA1

BALD1

PEFO1

SYCA1

WEMI1

WHRI1

MEVE1

SAPE1

CANY1

BRCA1

CAPI1

Average

Progress/

Baseline 

Ratio

Ammonium 

Sulfate

(Mm-1

)

Baseline 

Period 1.5 1.6 2.3 2.0 1.5 1.1 2.4 1.6 2.2 1.5 1.9

0.94

Progress 

Period 1.6 1.6 2.1 2.1 1.3 1.0 2.1 1.5 1.8 1.4 1.6

Ratio

(progress/

baseline)

1.08 0.96 0.95 1.03 0.91 0.96 0.87 0.94 0.84 0.92 0.84

Ammonium 

Nitrate

(Mm-1

)

Baseline 

Period 0.4 0.4 0.8 0.9 0.3 0.3 0.8 0.4 0.6 0.7 1.0

0.78

Progress 

Period 0.4 0.3 0.6 0.8 0.2 0.2 0.6 0.4 0.5 0.5 0.6

Ratio

(progress/

baseline)

1.01 0.74 0.78 0.92 0.72 0.73 0.67 0.83 0.89 0.76 0.56

Particulate 

Organic 

Carbon

(Mm-1

)

Baseline 

Period 0.6 1.2 1.9 2.4 1.2 0.6 1.5 0.7 1.1 1.0 1.3

0.72

Progress 

Period 0.5 1.2 1.5 1.8 0.9 0.3 1.0 0.6 0.7 0.7 0.9

Ratio

(progress/

baseline)

0.80 0.94 0.78 0.75 0.70 0.51 0.68 0.78 0.59 0.71 0.65

Light 

Absorbing 

Carbon

(Mm-1

)

Baseline 

Period 0.3 0.6 1.3 1.6 0.8 0.5 0.6 0.4 0.4 0.4 0.6

0.75

Progress 

Period 0.3 0.6 1.3 1.4 0.5 0.3 0.4 0.2 0.3 0.2 0.3

Ratio

(progress/

baseline)

0.87 0.92 0.99 0.88 0.70 0.72 0.68 0.63 0.70 0.60 0.57

Soil

(Mm-1

)

Baseline 

Period 0.1 0.2 0.4 0.7 0.2 0.1 0.4 0.2 0.3 0.1 0.3

0.90

Progress 

Period 0.2 0.2 0.4 0.6 0.2 0.1 0.2 0.1 0.2 0.1 0.2

Ratio

(progress/

baseline)

1.06 1.04 1.16 0.86 0.87 1.04 0.61 0.96 0.69 0.95 0.62

Coarse Mass

(Mm-1

)

Baseline 

Period 0.4 0.5 1.0 1.0 0.7 0.2 0.7 0.3 1.0 0.5 1.0

0.91

Progress 

Period 0.5 0.6 1.0 1.2 0.6 0.3 0.4 0.3 0.7 0.4 0.6

Ratio

(progress/

baseline)

1.05 1.29 1.01 1.13 0.89 1.02 0.59 1.02 0.75 0.71 0.60

Sea Salt

(Mm-1

)

Baseline 

Period 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1

2.50

Progress 

Period 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Ratio

(progress/

baseline)

1.53 8.34 4.45 2.42 1.24 1.25 1.03 1.02 1.51 3.92 0.78

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-8
Because of the logarithmic nature of the dv calculation (i.e., dv = 10ln(bext/10)), average 

dv ratios were not applied. Instead, in a manner consistent with RHR calculations, ratios were 

applied to individual species and individual days, and 5-year average deciview value was 

calculated from annual average deciviews, which were in turn calculated from daily average 

deciview value. Table 6.13-5 lists results for the ZICA1 site, where deciview values for the 

baseline period are approximated as being slightly higher than the measured progress period for 

both the 20% most impaired and least impaired days. These estimated baseline period averages 

are used to represent the ZICA1 for all summaries presented in this report. Note that similar 

baseline estimates have also been applied to estimate baseline conditions for the HACR1 site in 

Hawaii, as described in Section 6.5.1.1.

Table 6.13-5

ZICA1 Progress Period and Baseline Estimates

20% Least Impaired Days

ZICA1

2005-2009

Progress 

Period

Average of

Colorado Plateau 

Progress/Baseline 

Ratios

ZICA1

2000-2004

Baseline 

Estimate

Ammonium 

Sulfate

(Mm-1

)

20% Best Days 1.7 0.94 1.8

20% Worst Days 5.4 1.04 5.2

Ammonium 

Nitrate

(Mm-1

)

20% Best Days 0.6 0.78 0.8

20% Worst Days 1.9 0.86 2.2

Particulate 

Organic 

Carbon

(Mm-1)

20% Best Days 1.3 0.72 1.8

20% Worst Days 8.5 0.91 9.3

Light 

Absorbing 

Carbon

(Mm-1)

20% Best Days 0.6 0.75 0.8

20% Worst Days 2.4 0.98 2.4

Soil

(Mm-1

)

20% Best Days 0.3 0.90 0.3

20% Worst Days 1.8 1.07 1.7

Coarse Mass

(Mm-1

)

20% Best Days 1.0 0.91 1.1

20% Worst Days 5.6 1.00 5.6

Sea Salt

(Mm-1

)

20% Best Days 0.0 2.50 0.0

20% Worst Days 0.1 2.31 0.1

Deciviews (dv)

20% Best Days 4.3 N/A 5.0*

20% Worst Days 12.3 N/A 12.5*

*Calculated from daily average bext determined using species specific average ratios from all Colorado 

Plateau sites.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-9
6.13.1.2 Current Conditions

This section addresses the regulatory question, what are the current visibility conditions 

for the most impaired and least impaired days (40 CFR 51.309(d)(10)(i)(C))? RHR guidance 

specifies that 5-year averages be calculated over successive 5-year periods, i.e. 2000-2004, 

2005-2009, 2010-2014, etc.4 Current visibility conditions are represented here as the most recent 

successive 5-year average period available, or the 2005-2009 period average, although the most 

recent IMPROVE monitoring data currently available includes 2010 data.

Tables 6.13-6 and 6.13-7 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% 

most impaired, or worst, and 20% least impaired, or best, days for each of the Federal CIA 

IMPROVE monitors in Utah. Figure 6.13-4 presents 5-year average extinction for the current 

progress period for both the 20% most impaired and 20% least impaired 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 best days was less than Rayleigh, 

or the background scattering that would occur in clear air. Average extinction 

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

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

aerosol species of extinction

4 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.)

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-10

 
Table 6.13-6

Utah Class I Area IMPROVE Sites

Current Visibility Conditions

2005-2009 Progress Period, 20% Most Impaired Days

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)

*Highest aerosol species contribution per site is highlighted in bold.

Table 6.13-7

Utah Class I Area IMPROVE Sites

Current Visibility Conditions

2005-2009 Progress Period, 20% Least Impaired Days

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 2.1 40% (1) 15% (3) 22% (2) 7% (5) 4% (6) 11% (4) 1% (7)

CANY1 2.8 43% (1) 12% (4) 15% (3) 7% (5) 5% (6) 17% (2) 1% (7)

CAPI1 2.7 38% (1) 13% (4) 21% (2) 8% (5) 5% (6) 14% (3) 1% (7)

ZICA1 4.3 30% (1) 11% (4) 23% (2) 10% (5) 6% (6) 18% (3) 1% (7)

*Highest aerosol species contribution per site is highlighted in bold.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-11
11.9 dv

2.1

11.0

2.8

11.3

2.7

12.3

4.3

0

5

10

15

20

25

30

35

40

45

W B W B W B W B

BRCA1 CANY1 CAPI1 ZICA1

Extinction* (Mm-1)

First Progress Period (2005-2009)

Average Extinction, 20% Worst (W) and Best (B) Days

Sea Salt

Coarse Mass

Soil

Elemental Carbon

Particulate Organic Mass

Ammonium Nitrate

Ammonium Sulfate

Rayleigh

*Visibility impairment in deciviews (dv) is shown above respective bars.

Figure 6.13-4. 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. 

6.13.1.3 Differences between Current and Baseline Conditions

This section addresses the regulatory question, what is the difference between current 

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

conditions (40 CFR 51.309(d)(10)(i)(C))? Included here are comparisons between the 5-year 

average baseline conditions (2000-2004) and current progress period extinction (2005-2009).

Table 6.13-8 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 6.13-9 presents similar data for the least impaired days. Averages that 

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

Figure 6.13-5 presents the 5-year average extinction for the baseline and current progress 

period averages for the worst days and Figure 6.13-6 presents the differences in averages by 

aerosol species, with increases represented above the zero line and decreases below the zero line. 

Figures 6.13-7 and 6.13-8 present similar plots for the best days.

For the 20% most impaired days, the 5-year average 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 

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-12
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.

• Ammonium sulfate decreased at all sites except ZICA1. Note that the ZICA1 site did 

not measure during the baseline years, and changes reported here are proportional to 

average changes in extinction as measured at regional sites as discussed in Section 

6.13.1.1.

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.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-13
Table 6.13-8

Utah Class I Area IMPROVE Sites

Difference in Aerosol Extinction by Species

2000-2004 Baseline Period to 2005-2009 Progress Period

20% Most 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 11.6 11.9 +0.3 -0.2 -0.3 +2.5 +0.2 +0.1 -0.9 0.0

CANY1 11.2 11.0 -0.2 -0.3 +0.3 -0.9 -0.1 +0.1 +0.8 0.0

CAPI1 10.9 11.3 +0.4 -0.2 -0.7 +1.8 +0.2 +0.3 +0.7 +0.1

ZICA1 12.5 12.3 -0.2 +0.2 -0.3 -0.8 -0.1 +0.1 0.0 +0.1

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

extinction and values in blue indicate decreases.

Table 6.13-9

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.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-14
11.6 dv11.9

11.2 11.0 10.9

11.3

12.5 12.3

0

5

10

15

20

25

30

35

40

45

B P B P B P B P

BRCA1 CANY1 CAPI1 ZICA1

Extinction* (Mm-1)

Baseline (B) and First Progress (P) Period

Average Extinction, 20% Worst Days

Sea Salt

Coarse Mass

Soil

Elemental Carbon

Particulate Organic Mass

Ammonium Nitrate

Ammonium Sulfate

Rayleigh

*Visibility impairment in deciviews (dv) is shown above respective bars.

Figure 6.13-5. Average Extinction for Baseline and Progress Period Extinction for Worst (Most 

Impaired) Days Measured at Utah Class I Area IMPROVE Sites.

Δdv = +0.3

-0.2

+0.4

-0.2

-2

-1

0

1

2

3

4

5

BRCA1 CANY1 CAPI1 ZICA1

Change in Extinction* (Mm-1)

First Progress Period - Baseline Period

Change in Extinction, 20% Worst Days

Sea Salt

Coarse Mass

Soil

Elemental Carbon

Particulate Organic Mass

Ammonium Nitrate

Ammonium Sulfate

*Change in visibility impairment in deciviews (dv) is shown above respective bars.

Figure 6.13-6. 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. 

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-15
2.8 dv

2.1

3.7

2.8

4.1

2.7

5.0

4.3

0

2

4

6

8

10

12

14

16

18

20

B P B P B P B P

BRCA1 CANY1 CAPI1 ZICA1

Extinction* (Mm-1)

Baseline (B) and First Progress (P) Period

Average Extinction, 20% Best Days

Sea Salt

Coarse Mass

Soil

Elemental Carbon

Particulate Organic Mass

Ammonium Nitrate

Ammonium Sulfate

Rayleigh

*Visibility impairment in deciviews (dv) is shown above respective bars.

Figure 6.13-7. Average Extinction for Baseline and Progress Period Extinction for Best (Least 

Impaired) Days Measured at Utah Class I Area IMPROVE Sites.

Δdv = -0.7 -0.9 -1.4 -0.7

-2.5

-2

-1.5

-1

-0.5

0

0.5

BRCA1 CANY1 CAPI1 ZICA1

Change in Extinction (Mm-1)

First Progress Period - Baseline Period

Change in Extinction, 20% Best Days

Sea Salt

Coarse Mass

Soil

Elemental Carbon

Particulate Organic Mass

Ammonium Nitrate

Ammonium Sulfate

*Change in visibility impairment in deciviews (dv) is shown above respective bars.

Figure 6.13-8. 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.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-16
6.13.1.4 Changes in Visibility Impairment

This section addresses the regulatory question, what is the change in visibility 

impairment for the most impaired and least impaired days over the past 5 years (40 CFR 

51.309(d)(10)(i)(C))? 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 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 6.13-10, and regional trends were presented earlier in Section 4.1.1.5 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.6 In some 

cases, trends may show decreasing tendencies while the difference between the 5-year averages 

do not (or vice versa), as discussed in Section 3.1.2.2. In these cases, the 5-year average for the 

best and worst days is the important metric for 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. Additionally, the appendix includes plots 

depicting 5-year, annual, monthly and daily average extinction for each site. These plots are 

intended to provide a fairly comprehensive compilation of reference information for individual 

states to investigate local and regional events and outliers that may have influenced changes in 

visibility impairment as tracked using the 5-year deciview metrics. Note that similar summary 

products are also available from the WRAP TSS website (http://vista.cira.colostate.edu/tss/). 

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 sites 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 a 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 

5 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) 6 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.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-17

 
sulfate was reported for the ZICA1 site, but this was based on a baseline average 

estimate as described in Section 6.13.1.1. Actual data measured between 2004 and 

2009 at the ZICA1 site indicated a slightly decreasing annual average trend.

• 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 trends 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 6.13-10

Utah Class I Area IMPROVE Sites

Change in Aerosol Extinction by Species

2000-2009 Annual Average Trends

Site Group

Annual Trend* (Mm-1/year)

Ammonium 

Sulfate

Ammonium 

Nitrate

Particulate 

Organic 

Mass

Elemental 

Carbon Soil Coarse Mass

Sea 

Salt

BRCA1

20% Best -- 0.0 -0.1 0.0 -- 0.0 0.0

20% Worst -0.2 -- 0.5 0.1 -- -- 0.0

All Days -0.1 0.0 -- -- -- -- --

CANY1

20% Best -0.1 -- -0.1 0.0 -- -0.1 0.0

20% Worst -0.1 -- -- -- -- -- 0.0

All Days -0.1 0.0 -- 0.0 0.0 -- 0.0

CAPI1

20% Best -0.1 -0.1 -0.1 0.0 -- -0.1 --

20% Worst -- -0.2 -- -- 0.1 -- 0.0

All Days -0.1 -0.1 -- 0.0 -- -- 0.0

ZICA1

20% Best 0.0 -- -- 0.0 0.0 -- 0.0

20% Worst -0.5 -- -- -- -- -- --

All Days -0.2 -- -- -0.1 0.1 -- --

*(--) Indicates statistically insignificant trend (<85% confidence level). Annual averages and complete trend 

statistics for all significance levels are included for each site in Appendix M.

6.13.2 Emissions Data

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, as referenced in Section 3.2.1. For reference, Table 6.13-7 

lists the major emitted pollutants inventoried, the related aerosol species, some of the major 

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

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-18
between these baseline and progress period inventories, and a separate summary of annual 

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

Table 6.13-11

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 and 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 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 

Organic 

Aerosol 

(POA)

POM Wildfires;

Area Sources

POA represents organic aerosols that are emitted directly as 

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

dominate POA emissions, and large wildfire events are generally 

sporadic and highly variable from year-to-year.

Elemental 

Carbon 

(EC)

EC Wildfires;

On- and OffRoad Mobile 

Sources

Large EC events are often associated with large POM events 

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

diesel engines.

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.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-19
6.13.2.1 Changes in Emissions

This section addresses the regulatory question, what is the change over the past 5 years 

in emissions of pollutants contributing to visibility impairment from all sources and activities 

within the State (40 CFR 51.309(d)(10)(i)(D))? 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 RHR 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 

WestJumpAQMS and DEASCO3 modeling projects (termed WestJump2008). Note that the 

comparisons 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, as referenced in Section 3.2.1. Inventories for all 

major visibility impairing pollutants are presented for major source categories, and categorized 

as either anthropogenic or natural emissions. State-wide inventories totals and differences are 

presented here, and inventory totals on a county level basis are available on the WRAP Technical 

Support System website (http://vista.cira.colostate.edu/tss/).

Table 6.13-12 and Figure 6.13-9 present the differences between the 2002 and 2008 

sulfur dioxide (SO2) inventories by source category. Tables 6.13-13 and Figure 6.13-10 present 

data for oxides of nitrogen (NOX), and subsequent tables and figures (Tables 6.13-14 through 

6.13-19 and Figures 6.13-10 through 6.13-16) present data for ammonia (NH3), volatile organic 

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

coarse mass. Inventory totals on a county level basis will be made available on the WRAP TSS 

website (http://vista.cira.colostate.edu/tss/). General observations regarding emissions inventory 

comparisons are listed below.

• Largest differences for point source inventories were a decrease in SO2 emissions and 

an increases 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, as referenced in 

Section 3.2.1. 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 onroad models, as referenced in Section 3.2.1.

• 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 Regional Haze Rule Reasonable Progress Report Support Document 6-20
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.

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.

• 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.

• 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.

• 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, as referenced in Section 

3.2.1, rather than changes in actual emissions.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-21
Table 6.13-12

Utah

Sulfur Dioxide Emissions by Category

Source Category

Sulfur Dioxide Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 41,863 28,206 -13,658

Area 3,434 1,988 -1,447

On-Road Mobile 1,777 497 -1,280

Off-Road Mobile 4,504 286 -4,218

Area Oil and Gas 17 114 98

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 70 8 -62

Total Anthropogenic 51,665 31,099 -20,566 (-40%)

Natural Sources

Natural Fire 2,418 92 -2,326

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 2,418 92 -2,326 (-96%)

All Sources

Total Emissions 54,083 31,190 -22,892 (-42%)

Figure 6.13-9. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Sulfur Dioxide by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-22
Table 6.13-13

Utah

Oxides of Nitrogen Emissions by Category

Source Category

Oxides of Nitrogen Emissions (tons/year)

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 6.13-10. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Oxides of nitrogen by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-23
Table 6.13-14

Utah

Ammonia Emissions by Category

Source Category

Ammonia Emissions (tons/year)

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 6.13-11. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Ammonia by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-24
Table 6.13-15

Utah

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 6.13-12. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Volatile Organic Compounds by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-25
Table 6.13-16

Utah

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%)

*Point source data includes only oil and gas and regulated CEM sources. More comprehensive point source data 

were not available at the time this report was prepared but will be made available through the WRAP TSS 

(http://vista.cira.colostate.edu/tss/).

Figure 6.13-13. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Primary Organic Aerosol by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-26
Table 6.13-17

Utah

Elemental Carbon Emissions by Category

Source Category

Elemental Carbon Emissions (tons/year)

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%)

*Point source data includes only oil and gas and regulated CEM sources. More comprehensive point source data 

were not available at the time this report was prepared but will be made available through the WRAP TSS 

(http://vista.cira.colostate.edu/tss/).

Figure 6.14-12. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Elemental Carbon by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-27
Table 6.13-18

Utah

Fine Soil Emissions by Category

Source Category

Fine Soil Emissions (tons/year)

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%)

*Point source data includes only oil and gas and regulated CEM sources. More comprehensive point source data 

were not available at the time this report was prepared but will be made available through the WRAP TSS 

(http://vista.cira.colostate.edu/tss/).

Figure 6.13-15. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Fine Soil by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-28
Table 6.13-19

Utah

Coarse Mass Emissions by Category

Source Category

Coarse Mass Emissions (tons/year)

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%)

*Point source data includes only oil and gas and regulated CEM sources. More comprehensive point source data 

were not available at the time this report was prepared but will be made available through the WRAP TSS 

(http://vista.cira.colostate.edu/tss/).

Figure 6.13-16. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, 

for Coarse Mass by Source Category for Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-29
6.13.2.2 EGU Summary

As described in previous sections, 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 entire 5-year 

monitoring periods compared. To better account for year-to-year changes in emissions, annual 

emission totals for Utah electrical generating units (EGU) 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 6.13-17 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.

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

199619971998199920002001200220032004200520062007200820092010

Annual EGU Emissions

Utah 1996-2010

SO2 (TPY)

NOX (TPY)

Figure 6.13-17. Sum of EGU Emissions of SO2 and NOX reported between 1996 and 2010 for 

Utah.

WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-30