Nevada Regional Haze 5-Year Progress Report, November 2014

APPENDIX A

Western Regional Air Partnership 

Regional Haze Rule Reasonable Progress 

Summary Report, June 28, 2013

Section 6.8 Nevada
Nevada Regional Haze 5-Year Progress Report, November 2014
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-1

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 6-2

6.8 Nevada

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. Nevada has one mandatory 

Federal Class I area, which is depicted in Figure 6.8-1 and listed in Table 6.8-1, 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. In general, comparisons of anthropogenic 

emissions inventory totals for the state showed net decreases, while several of the monitored 

species increased. Because the JARB1 site is on the northern edge of Nevada, it is likely that 

regional emissions sources from outside of the state influences the increases in monitored data. 

Some additional highlights regarding comparisons between the 2000-2004 baseline and 

2005-2009 progress period are listed below, and more detailed state specific information is 

provided in monitoring and emissions sub-sections that follow.

 For the 20% best days, the 5-year average deciview metric decreased at the JARB1 

site.

 For the 20% worst days, the 5-year average deciview metric increased at the JARB1, 

site.

 The increase in the 20% worst day 5-year average deciview value was due to small 

increases in all aerosol species except particulate organic mass. For these increases:

- No statistically significant increasing annual trends for any aerosol species 

occurred for the period 2000-2009.

- Higher than average monitored ammonium sulfate and ammonium nitrate 

concentrations in 2005 influenced the 5-year progress period average for these 

species.

 Emissions inventories indicated net decreases for SO2 and NOX between the baseline 

and 2008 emission inventories. For emissions comparisons:

- Slight increases in on-road mobile and area source inventory totals were offset by 

larger decreases in point and off-road mobile totals.

- Annual total EGU emissions for the state showed dramatic decreases in SO2 and 

NOX.

 The fine soil and coarse mass emissions inventories showed increases in fugitive dust

and natural windblown dust, which was likely due to updates in inventory 

development methodologies rather than actual increases.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-3

Figure 6.8-1. Map Depicting the Federal CIA and Representative IMPROVE Monitor in 

Nevada.

Table 6.8-1

Nevada Class I Area and Representative IMPROVE Monitor

Class I Area Representative 

IMPROVE Site Latitude Longitude Elevation (m)

Jarbidge WA JARB1 41.89 -115.43 1869

6.8.1 Monitoring Data

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

the JARB1 IMPROVE monitor, representing the Jarbridge Wilderness Area, which is the only 

Federal CIA in Nevada. These summaries are supported by regional data presented in Section 4.0 

and by more detailed site specific tables and charts in Appendix H.

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 

Mount Baldy WA

Big Bend 

Chiricahua WA

Galiuro WA

Chiricahua NM

Diamond Peak WA

Crater Lake NP

NP

Haleakala NP

Hawaii Volcanoes NP

Jarbidge WA

Kalmiopsis WA

Raw

Mount Zirkel WA

Ro

Saguaro WA

Three Sisters WA

Superstition WA

Eagles N

Flat Tops WA

Maroon Bells-Snowmass WA

West Elk WA

BALD1

CHIR1

CRLA1

DENA1

HACR1

HALE1

HAVO1

JARB1

KALM1

MOZI1

RO

SAGU1

TONT1

WHRI1
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-4

both the deciview metric, and the apportionment of haze into extinction due to the various 

measured species in units of inverse megameters (Mm-1). 

6.8.1.1 Current Conditions

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

for the most impaired and least impaired days (40 CFR 51.308 (g)(3)(i))? RHR guidance 

specifies that 5-year averages be calculated over successive 5-year periods, i.e. 2000-2004, 2005-

2009, 2010-2014, etc.1 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 6.8-2 and 6.8-3 present the calculated deciview values for the JARB1 site, along 

with the percent contribution to extinction from each aerosol species for the 20% most impaired 

and 20% least impaired days. Figure 6.8-2 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, or 

worst, days are as follows:

 The largest contributor to aerosol extinction on the worst days at the JARB1 site was

particulate organic mass, followed by coarse mass and ammonium sulfate.

Specific observations for the current visibility conditions on the 20% least impaired, or 

best, days are as follows:

 Rayleigh, or background visibility impairment in clean air, contributed to 

approximately 80% of the total extinction (in Mm-1) for the best days. Aerosol species 

contributions in Table 6.8-3 exclude the Rayleigh portion of extinction.

 Ammonium sulfate is the largest contributor to aerosol extinction for the best days.

 

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

Table 6.8-2

Nevada Class I Area IMPROVE Site

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

JARB1 12.4 17% (3) 5% (6) 38% (1) 7% (5) 10% (4) 22% (2) 1% (7)

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

Table 6.8-3

Nevada Class I Area IMPROVE Site

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

JARB1 2.2 47% (1) 8% (4) 19% (2) 7% (5) 4% (6) 13% (3) 2% (7)

*Highest aerosol species contribution per site is highlighted in bold.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-6

Figure 6.8-2. Average Extinction for Current Progress Period (2005-2009) for the Worst (Most 

Impaired) and Best (Least Impaired) Days Measured at the Nevada Class I Area IMPROVE Site. 

6.8.1.2 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 51.308 (g)(3)(ii))? Included here are comparisons between the 5-year 

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

Table 6.8-4 presents the differences between the 2000-2004 baseline period average 

extinction and the 2005-2009 progress period average for the JARB1 site in Nevada for the 20% 

most impaired days, and Table 6.8-5 presents similar data for the least impaired days. Averages 

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

Figure 6.8-3 presents the 5-year average extinction for the baseline and current progress 

period averages for the worst days and Figure 6.8-4 presents the differences in averages by 

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

Figures 6.8-5 and 6.8-6 present similar plots for the best days.

For the 20% most impaired days, the 5-year average RHR deciview metric increased at 

the JARB1 site. Notable differences for individual species averages on the most impaired days 

were as follows:

12.4dv

2.2

0

5

10

15

20

25

30

35

40

45

W B

JARB1

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 is shown above respective bars.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-7

 All species except particulate organic mass increased slightly at the JARB1 site. The 

largest increases were measured for ammonium sulfate, coarse mass and ammonium 

nitrate.

 Increases in 5-year average ammonium nitrate at the JARB1 monitor were influenced 

by higher than average ammonium nitrate in 2005, where anomalously high 

measurements on December 18, 2005, as depicted in Appendix H, Figure H.1-8, 

influenced the annual average.

For the 20% least impaired or best days, the 5-year average deciview metric decreased at 

the JARB1 site. Notable differences for individual species averages on the best impaired days 

were as follows:

 The largest decrease on the best days was measured for particulate organic mass. Soil, 

coarse mass and sea salt measured very small increases for the best days.

Table 6.8-4

Nevada 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-

2004

Baseline

Period

2005-

2009

Progress

Period

Change 

in dv*

Amm.

Sulfate

Amm.

Nitrate POM EC Soil CM SeaSalt

JARB1 12.1 12.4 +0.3 +0.4 +0.3 0.0 +0.1 +0.2 +0.4 +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 6.8-5

Nevada 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-

2004

Baseline

Period

2005-

2009

Progress

Period

Change 

in dv*

Amm.

Sulfate

Amm.

Nitrate POM EC Soil CM SeaSalt

JARB1 2.6 2.2 -0.4 -0.1 -0.1 -0.3 -0.1 0.0 0.0 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 6-8

Figure 6.8-3. Average Extinction for Baseline and Progress Period Extinction for Worst (Most 

Impaired) Days Measured at the Nevada Class I Area IMPROVE Site. 

Figure 6.8-4. Difference between Average Extinction for Current Progress Period (2005-2009) 

and Baseline Period (2000-2004) for the Worst (Most Impaired) Days Measured at the Nevada 

Class I Area IMPROVE Site. 

. 

12.1dv 12.4

0

5

10

15

20

25

30

35

40

45

B P

JARB1

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.

Δdv = +0.3

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

JARB1

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

Figure 6.8-5. Average Extinction for Baseline and Progress Period Extinction for Best (Least 

Impaired) Days Measured at the Nevada Class I Area IMPROVE Site.

Figure 6.8-6. Difference between Average Extinction for Current Progress Period (2005-2009) 

and Baseline Period (2000-2004) for the Best (Least Impaired) Days Measured at the Nevada

Class I Area IMPROVE Site.

2.6dv 2.2

0

2

4

6

8

10

12

14

16

B P

JARB1

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.

Δdv = -0.4

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

JARB1

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

6.8.1.3 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 

51.308 (g)(3)(iii))? 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 species at the Nevada site are summarized in 

Table 6.8-6, and regional trends were presented earlier in Section 4.1.1.2 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.3In 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 H. Additionally, this 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 Nevada are as 

follows:

 No increasing aerosol trends were observed at the JARB1 site for the best, worst or 

all sample days.

 Only particulate organic mass (20% best and all days) and elemental carbon (20% 

worst days) exhibited statistically significant trends, all decreasing. All other species 

did not show statistically significant trends for the best, worst or all days from 2000 to 

2009.

 

2 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)

3 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 6-11

Table 6.8-6

Nevada Class I Area IMPROVE Site

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

JARB1

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

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

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

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

complete trend statistics for all significance levels are included for each site in Appendix H.

6.8.2 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 6.8-7 

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 

between these baseline and progress period inventories, and a separate summary of annual 

emissions from electrical generating units (EGUs), are presented in this section.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-12

Table 6.8-7

Nevada

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 6-13

6.8.2.1 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 51.308 (g)(4))? 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 6.8-8 and Figure 6.8-7 present the differences between the 2002 and 2008 sulfur 

dioxide (SO2) inventories by source category. Tables 6.8-9 and Figure 6.8-8 present data for 

oxides of nitrogen (NOX), and subsequent tables and figures (Tables 6.8-10 through 6.8-15 and 

Figures 6.8-9 through 6.8-14) 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.

 State-wide SO2 inventory totals show a 75% reduction, with some decreases reported 

for all source categories. The largest decreases are reported from point sources, 

followed by area sources, natural fire and off-road mobile sources. 

 NOX emissions show a 22% reduction, with area and on-road mobile sources showing 

significant increases, while all other source categories show decreases. The largest 

decreases were reported from point sources, followed by off-road mobile, biogenic 

emissions, and natural fire sources. Note that decreases in biogenic sources were 

consistent for all contiguous WRAP states, and likely due to inventory enhancements 

in 2008. Also, current natural fire emissions represent only the year 2008, so all fire 

events for the 2005-2009 progress period are not represented in these emissions 

comparison results. Also, for off-road sources, 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.

 Ammonia emission inventory totals decreased by 34%, with decreases due mostly to 

area and off-road mobile sources.

 VOC emissions showed a 61% decrease, mostly due to biogenic emission inventories. 

A significant increase is shown for area sources. Significant decreases are shown for 

biogenic, on-road mobile and natural fire sources. The large difference in biogenic 

emissions is likely due to enhancements in biogenic inventory methodology, as 
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-14

described in Section 3.2, rather than decreases of this magnitude in actual emissions.

Also, current natural fire emissions represent only the year 2008, so all fire events for 

the 2005-2009 progress period are not represented in these emissions comparison 

results.

 POA showed 52% decrease in inventory totals, and elemental carbon showed a 31% 

decrease, mostly due to natural fire sources. Note that current natural fire emissions 

represent only the year 2008, so all fire events for the 2005-2009 progress period are 

not represented in these emissions comparison results.

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

and the combined fugitive/road dust inventories. The large increases in windblown 

dust are likely due in part to enhancements in dust inventory methodology, as 

described in Section 3.2, rather than increases in actual emissions. Most other sources 

of fine soil and coarse mass showed increases with the exception of natural fire 

sources for both pollutants, on-road mobile sources for fine soil, and point sources for 

coarse mass.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-15

Table 6.8-8

Nevada

Sulfur Dioxide Emissions by Category

Source Category

Sulfur Dioxide Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 50,720 11,155 -39,565

Area 12,953 4,863 -8,090

On-Road Mobile 454 298 -156

Off-Road Mobile 1,403 322 -1,081

Area Oil and Gas 0 0 0

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 12 2 -11

Total Anthropogenic 65,543 16,641 -48,903 (-75%)

Natural Sources

Natural Fire 2,200 506 -1,695

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 2,200 506 -1,695 (-77%)

All Sources

Total Emissions 67,743 17,146 -50,597 (-75%)

Figure 6.8-7. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Sulfur Dioxide by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-16

Table 6.8-9

Nevada

Oxides of Nitrogen Emissions by Category

Source Category

Oxides of nitrogen Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 59,864 30,090 -29,774

Area 5,725 11,321 5,597

On-Road Mobile 41,089 50,068 8,979

Off-Road Mobile 32,565 17,081 -15,484

Area Oil and Gas 63 0 -63

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 48 13 -35

Total Anthropogenic 139,353 108,574 -30,779 (-22%)

Natural Sources

Natural Fire 8,026 3,575 -4,451

Biogenic 15,018 7,364 -7,654

Wind Blown Dust 0 0 0

Total Natural 23,044 10,939 -12,105 (-53%)

All Sources

Total Emissions 162,397 119,513 -42,885 (-26%)

Figure 6.8-8. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Oxides of nitrogen by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-17

Table 6.8-10

Nevada

Ammonia Emissions by Category

Source Category

Ammonia Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 339 302 -37

Area 8,009 5,717 -2,293

On-Road Mobile 2,030 849 -1,182

Off-Road Mobile 22 20 -2

Area Oil and Gas 0 0 0

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 8 6 -2

Total Anthropogenic 10,408 6,893 -3,515 (-34%)

Natural Sources

Natural Fire 1,684 2,490 805

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 1,684 2,490 805 (48%)

All Sources

Total Emissions 12,092 9,382 -2,710 (-22%)

Figure 6.8-9. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Ammonia by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-18

Table 6.8-11

Nevada

Volatile Organic Compound Emissions by Category

Source Category

Volatile Organic Compound Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point 2,215 2,953 738

Area 28,592 40,973 12,381

On-Road Mobile 36,257 21,302 -14,955

Off-Road Mobile 18,094 18,783 688

Area Oil and Gas 129 0 -129

Fugitive and Road Dust 0 0 0

Anthropogenic Fire 70 16 -54

Total Anthropogenic 85,357 84,026 -1,331 (-2%)

Natural Sources

Natural Fire 17,606 4,204 -13,403

Biogenic 794,139 262,912 -531,227

Wind Blown Dust 0 0 0

Total Natural 811,745 267,115 -544,630 (-67%)

All Sources

Total Emissions 897,102 351,142 -545,960 (-61%)

Figure 6.8-10. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Volatile Organic Compounds by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-19

Table 6.8-12

Nevada

Primary Organic Aerosol Emissions by Category

Source Category

Primary Organic Aerosol Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point* 256 46 -210

Area 687 2,283 1,596

On-Road Mobile 314 1,053 739

Off-Road Mobile 572 689 117

Area Oil and Gas 0 0 0

Fugitive and Road Dust 332 891 559

Anthropogenic Fire 73 22 -51

Total Anthropogenic 2,233 4,985 2,751 (>100%)

Natural Sources

Natural Fire 22,501 6,831 -15,670

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 22,501 6,831 -15,670 (-70%)

All Sources

Total Emissions 24,734 11,816 -12,918 (-52%)

*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 6.8-11. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Primary Organic Aerosol by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-20

Table 6.8-13

Nevada

Elemental Carbon Emissions by Category

Source Category

Elemental Carbon Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point* 13 64 50

Area 96 368 272

On-Road Mobile 235 1,891 1,656

Off-Road Mobile 1,354 954 -400

Area Oil and Gas 0 0 0

Fugitive and Road Dust 24 14 -10

Anthropogenic Fire 13 6 -8

Total Anthropogenic 1,735 3,295 1,561 (90%)

Natural Sources

Natural Fire 4,674 1,130 -3,544

Biogenic 0 0 0

Wind Blown Dust 0 0 0

Total Natural 4,674 1,130 -3,544 (-76%)

All Sources

Total Emissions 6,409 4,425 -1,984 (-31%)

*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 6.8-12. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Elemental Carbon by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-21

Table 6.8-14

Nevada

Fine Soil Emissions by Category

Source Category

Fine Soil Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point* 2,158 209 -1,948

Area 830 1,024 195

On-Road Mobile 239 190 -49

Off-Road Mobile 0 49 49

Area Oil and Gas 0 0 0

Fugitive and Road Dust 6,128 19,216 13,087

Anthropogenic Fire 9 10 1

Total Anthropogenic 9,364 20,698 11,334 (>100%)

Natural Sources

Natural Fire 1,406 2,552 1,146

Biogenic 0 0 0

Wind Blown Dust 10,438 17,051 6,613

Total Natural 11,845 19,603 7,758 (66%)

All Sources

Total Emissions 21,208 40,301 19,092 (90%)

*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 6.8-13. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Fine Soil by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-22

Table 6.8-15

Nevada

Coarse Mass Emissions by Category

Source Category

Coarse Mass Emissions (tons/year)

2002

(Plan02d)

2008

(WestJump2008)

Difference

(Percent Change)

Anthropogenic Sources

Point* 4,093 1,761 -2,331

Area 897 1,094 198

On-Road Mobile 245 2,014 1,769

Off-Road Mobile 0 82 82

Area Oil and Gas 0 0 0

Fugitive and Road Dust 56,779 161,532 104,753

Anthropogenic Fire 7 4 -3

Total Anthropogenic 62,020 166,488 104,468 (>100%)

Natural Sources

Natural Fire 5,176 1,310 -3,866

Biogenic 0 0 0

Wind Blown Dust 93,946 153,459 59,513

Total Natural 99,122 154,769 55,647 (56%)

All Sources

Total Emissions 161,142 321,257 160,115 (99%)

*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 6.8-14. 2002 and 2008 Emission and Difference between Emissions Inventory Totals, for 

Coarse Mass by Source Category for Nevada.
WRAP Regional Haze Rule Reasonable Progress Report Support Document 6-23

6.8.2.2 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 Nevada 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 6.8-15 presents a sum of annual NOX and SO2 emissions as reported for Nevada 

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 a sharp decline for SO2 and NOX between 2005 and 

2006, mostly resulting from the closure of the Mohave Generating Station in Clark County, 

which eliminated approximately 20,000 tons per year (tpy) of NOx and 41,000 tpy of SO2

emissions. Steady decreases for NOX emissions are shown for 2006 through 2010.

Figure 6.8-15. Sum of EGU Emissions of SO2 and NOX reported between 1996 and 2010 for 

Nevada.

0

10,000

20,000

30,000

40,000

50,000

60,000 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Annual EGU Emissions

Nevada 1996-2010

SO2 (TPY)

NOX (TPY)