Draft Comments Wyoming Draft Haze SIP September 2 9 , 2009 Pat Brewer

Section 2 and 3 describe the WY Class I areas and the visibility monitoring data that define the 20% worst and 20% best visibility days at these areas. It would be helpful to at least cite references , if not include in the SIP, d iscussion s how light extinction and deciview are calculated from IMPROVE
measurements (sections 2 and 3) , and how relative response factors are calculated to project future visibility (Section 5)

.

In Section 4, WY reports emissions from the WRAP 2002d and 2018PRPb inventories. WY should clarify that you accept WRAP emissions projections for WY sources as representative of all WY controls by 2018. In particular, are all WY BART reductions included in WRAP 20 18PRPb? If some or all of WY BART NOx controls are missing from the WRAP 2018PRPb, benefits from these controls are missing from the WRAP CMAQ 2018 projections and PSAT source attribution that are the basis for W Y’s reasonable progress analyses. Table 4 .3

- 1 reports a 7% decrease in NOx emissions by 2018 from point sources. If a larger reduction is expected from BART, it would be helpful in Table 4.3

- 1 to separately list BART EGU,

non

- BART EGU, and industrial point. The majority of the NOx reductions pr ojected for 2018 are due to reductions in the mobile onroad and nonroad sectors. The pro jected increase in NOx emissions from oil and gas (132%) indicates that NOx controls f or oil and gas should be considered as part of reasonable progress analyses.

In Section 5, WY cites WRAP CAMx

- PSAT analyses of contributions to SO4 and NO3 from different source regions and CMAQ projections of 2018 progress

. The inventories and models are subtly different so you are seeing subtle differences in the results. It woul d be helpful to make that clearer in the discussion on page 48. For example, how are SO2 emissions in WY different between the two sets of inventories? Only 2002pland and 2018PRPb are presented in section 4. Using CAMx

- PSAT and 2002planc and 2018 baseb emissions, Figures 5.2

- 1 through 5.2

- 3 indicate that SO4 mass does not change on 20% worst days between 2002 and 2018, despite SO2 reductions. Figures 5.2.1

- 1 through 5.2.1

- 3 also indicate slight increases in WY contributions to SO4 at the WY Class I are as in 2018 on the 20% worst days and slight increase in WRAP contributions t o SO4 at Bridger

. Using CMAQ and 2002pland and 2018PRPb emissions, Table 5.3.1

- 1 through 5.3.1

- 3 indicates the sulfate contribution s to light extinction do decrease between 2002 a nd 2018. T he differences in results are subtle but important if WY is citing these results to conclude that you do not need to consider SO2 reductions beyond those covered under the Section 309 SIP.

Section 7: Reasonable Progress Goals:

Section 7.5 (p 123) indicates that WY Reasonable Progress Goals for 20% Worst Days and 20% Best Days for Wyoming Class I areas are based on primarily on results of WRAP CMAQ modeling for 2018. It would be helpful to make clear that RPGs listed in Table 7.5

- 1 are the results of WRAP 2018b modeling without any additional controls beyond WRAP 2018b modeling.

WY s use s Q/d > 10 as an indicator of sources that should be considered for additional NOx controls for reasonable progress. Without more specific guidance from EPA, there is precedence that other stateshave used similar approach to screen sources. This criteria identifies only two units at Dave Johnson EGU, one unit at the Mountain Cement plant, and oil and gas exploration and productions. Highly c ost effectiv e NOx controls were identified in all cases. On page 125 item 4, WY indicates that significant reductions will be made from BART controls for coal fired power plants “as well as additional reductions committed to in the long term strategy. ” Yet n o additi onal NOx controls were included in WY’s long term strategy for controls by 2018

. Rather in Section 8.3 WY suggests that it will evaluate additional controls by the 2013 review. WY needs to make stronger commitments for additional controls for these

sourc es, particularly for oil a nd gas. Given the large increases in NOx emissions projected from oil and
gas, WY needs to make a commitment to control future growth in emissions.

WY asserts that uniform rate of progress will not be met because much of the contribution is from uncontrollable sources. We believe that WY should do more to adapt controls for reasonable progress where they are cost effective because WY is not meeting URP for sulfate and only barely meeting URP for nitrate, those pollutants whic h WY can control.

Section 8.1.2 .1: Class I areas affected by Wyoming Emissions WY cites WRAP PSAT analyses that project WY’s contributions to SO4 and NO3 at Class I areas in neighboring states and cites consultation through the WRAP process

.
WY’s long term strategy includes discussion of existing programs, including EPA discussions with Canada and Mexico over international emissions, existing WY control programs, natural events plan, measures to mitigate impacts from construction activities, and Smoke Management techniques. We ask that WY include in their discussion of New Source Review and Prevention of Significant Deterioration requirements recognition of visibility improvement goals so that progress in reducing emissions from existing sources is not offset by growth in new sources. We already are seeing such an offset due to increased emissions from oil and gas activities.