Nevada Regional Haze 5-Year Progress Report, November 2014 7-1

Chapter Seven – Assessment of Current SIP 

Strategy for Meeting Reasonable Progress 

Goals

(40 CFR 51.308(g)(6))

Table of Contents

7.1 Status Summary................................................................................................................ 2

7.2 Requirements.................................................................................................................... 2

7.3 Emissions Analysis .......................................................................................................... 3

7.4 Visibility Analysis............................................................................................................ 3

7.5 Conclusions...................................................................................................................... 4
Nevada Regional Haze 5-Year Progress Report, November 2014 7-2

7.1 Status Summary

This progress report clearly demonstrates that the current implementation plan elements and 

strategies outlined in the 2009 RH SIP are sufficient to enable Nevada to meet the reasonable 

progress goals for those extinction species that originate from anthropogenic sources. As shown

in Chapter Five, 2008 actual emissions are less, and in some cases far less, for all visibility 

impairing pollutants, except fine soil and coarse mass, than the projected 2018 emissions used to 

determine Nevada’s reasonable progress goal. Moreover, the expected future reductions in 

anthropogenic emissions based on further controls, shutdowns, and conversions to either natural 

gas or lower sulfur fuels will serve to enhance this downward trend in the coming years. See 

Chapter Two. 

Chapter Four clearly demonstrates that the visibility benefit from anthropogenic emission

reductions is hidden due to contributions from natural sources. Nonetheless, there are 

improvements in the haze index for the worst days, as well as in light extinction due to sulfate, 

nitrate and elemental carbon from the baseline to the current planning period. Visibility 

conditions for the best days show considerable improvement with a significant decrease in the 

haze index. Light extinction on the best days for all monitored species decreased or held steady 

from the baseline to the current planning period. 

Trend analysis of the 2000 to 2012 nitrate and sulfate annual extinction values demonstrates that 

the slopes of the trend lines are comparable to (sulfate) or better than (nitrate) the speciated glide 

slopes. Chapter Four, Section 

4.6.

7.2 Requirements

40 CFR 51.308(g)(6) requires

an assessment of whether the 

current SIP elements and 

strategies are sufficient to 

enable the state, or other Class I 

areas affected by emissions 

from the state, to meet all 

established reasonable progress 

goals.

1

 Because of the large 

contributions to visibility impairment due to natural source (non-anthropogenic) emissions, 

Nevada has focused its assessment of implementation plan elements and strategies on 

 

1

See the discussion in Chapter One of the correction to the 2018 visibility projection for Jarbidge WA conducted by 

the Regional Modeling Center. Nevada concludes that it is reasonable to retain the reasonable progress goal of 

11.05 deciviews, which aligns closely with the 2018 uniform rate of progress value for Jarbidge WA

51.308(g) . . . Periodic progress reports 

must contain at a minimum . . .

(6) 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.
Nevada Regional Haze 5-Year Progress Report, November 2014 7-3

impairment due to sulfate and nitrate light extinction resulting from largely anthropogenic 

emissions of SO2 and NOx, although other visibility impairing pollutants are also assessed. The 

RHR uses the uniform rate of progress (glidepath), measured as a haze index, toward “natural 

conditions” as the metric for determining whether a state is making reasonable progress. 

However, this measure puts most western states like Nevada, where visibility impairment from 

natural sources like wind-blown dust and wildfire overwhelms the visibility benefit from 

reduction of anthropogenic emissions, in an untenable position. The NDEP urges USEPA to 

revisit the RHR to establish a more appropriate and meaningful metric for measuring reasonable 

progress.

7.3 Emissions Analysis

An analysis of emission reductions in Nevada indicates that the state is on track to achieve its

emission reduction goals in 2018. Chapter Five presents visibility-impairing pollutant emission 

data for Nevada, which demonstrate the 2008 emission inventory is less than the projected 2018 

inventory with the exception of fine soil and coarse mass. See Table 5-1. Notably, actual 2008 

SO2 emissions are approximately 40 percent of the 2018 projected emissions, while the actual 

2008 NOx emissions are roughly 90 percent of the 2018 projection. Chapter Five compares 

sector-specific 2008 and 2011 NEI data, demonstrating further reductions in anthropogenic SO2

and NOx emissions from Nevada point sources. See Tables 5-6 and 5-8. The expected future 

reductions in anthropogenic emissions based on further controls, shutdowns, and conversions to 

natural gas, lower sulfur fuels, or renewables (see Chapter Two) will serve to continue this 

downward trend in the coming years. 

7.4 Visibility Analysis

Improvement in visibility conditions at JARB1 for the worst days has not kept pace with

Nevada’s emissions reductions due to large contributions from particulate organic matter. The 

improvement in visibility impairment, as measured by the haze index at JARB1, is not on the 

glide path for the worst days as discussed in Chapter Four. However, Table 4-2 shows that the

five-year annual average haze index and sulfate, nitrate, and elemental carbon light extinction 

values all improved from the baseline to the current planning period represented by 2008-2012

for the worst days. In addition, light extinction values for all the visibility-impairing pollutants 

decreased for the best days.

Figure 4-3 shows the large year-to-year variability of particulate organic matter extinction and its 

significant contribution and influence on the annual haze index, as well as the relatively flat 

contributions of the other species’ extinction for the worst days over time. Figure 4-4 

demonstrates the downward trends of the haze index and speciated extinction values, indicating 

continued improvement of visibility for the best days from 2001 to 2012. 

Visibility impairment at JARB1 for the worst days is dominated by emissions from natural 

sources that form particulate organic matter, and coarse mass emissions that originate roughly 
Nevada Regional Haze 5-Year Progress Report, November 2014 7-4

equally from anthropogenic and natural sources. Sulfate is the only significant contributor to 

visibility impairment at JARB1 that originates from anthropogenic sources. Nitrate originates 

from anthropogenic sources, but has only a small contribution to visibility impairment on the 

worst days. 

Trend analysis of the worst days annual JARB1 sulfate and nitrate monitor data from 2000 to 

2012 (see section 4.6) documents that the slopes of the trend lines for sulfate and nitrate are 

comparable to or better than the corresponding speciated glideslopes. The annual monitored 

sulfate and nitrate values are expected to continue or improve these trends in the coming years as 

BART control measures and other reasonable progress controls are implemented throughout the 

western United States. 

7.5 Conclusions

Nevada concludes that the current implementation plan elements and strategies outlined in the 

2009 RH SIP are sufficient to enable Nevada and other neighboring states to meet the reasonable 

progress goals for those extinction species that originate from anthropogenic sources given the 

following observations:

 Nevada has achieved significant emissions reductions in the first progress period.

 Emissions from natural sources play a much more dominant role in visibility impairment 

at JARB1 than emissions from anthropogenic sources.

 Visibility impairment resulting from sulfate and nitrate is decreasing at rates comparable 

or better than the speciated glideslopes.

 BART and other reasonable progress controls have not yet been fully implemented and 

the corresponding emission reductions have not yet been fully realized. Therefore, 

corresponding monitor results were not expected for this progress report. 

The NDEP committed in the Nevada RH SIP to re-examine the need for additional non-EGU 

controls during the State’s five-year progress report. As evidenced by the current and expected 

SO2 and NOx emissions reductions from EGUs, further reductions from non-utility, industrial 

point sources are unnecessary at this time.