'N REf".,- REFER TO

United States Department of the Interior

NATIONAL PARK SERVICE

Air Resources Division

P.O. Box 25287

Denver, CO 80225

I.t:::...t

~'"'\ TAKE PRIDE~

INAMERICA

October 21, 2009

N3615 (2350)

David A. Finley, Administrator

Division of Air Quality

Department of Environmental Quality

122 W. 25th Street

Cheyenne, Wyoming 82002

Dear Mr. Finley:

On August 26, 2009, we received Wyoming's draft regional haze implementation plan

for review. We appreciate the opportunity to work closely with the State through the

initial evaluation, development, and, now, subsequent review of this plan. Cooperative

efforts such as these ensure that, together, we will continue to make progress toward the

Clean Air Act's goal of natural visibility conditions at all of our most pristine National

Parks and wilderness areas for future generations.

This letter acknowledges that the U.S. Department of the Interior, U.S. Fish and Wildlife

Service (FWS), and National Park Service (NPS) have received and conducted a

substantive review of your revised proposed Regional Haze Rule implementation plan in

fulfillment of your requirements under the federal regulations 40 CFR 51.308(i)(2) and

51.309(g). Please note, however, that only the U.S. Environmental Protection Agency

(EPA) can make a final determination regarding the document's completeness and,

therefore, ability to receive federal approval from EPA.

As outlined in a letter to each State dated August 1, 2006, our review focused on eight

basic content areas. The content areas reflect priorities for the Federal Land Manager

agencies, and we have enclosed comments associated with these priorities. Overall the

draft implementation plan was well organized and addressed all the key elements outlined

in our letter. We recognize Wyoming is committing to significant point SOllce emissions

reductions. We have two primary concerns with the draft plan: 1) the reasonable

progress analyses did not consider what S02 controls beyond those included in the

Section 309 State Implementation Plan might be reasonable to address visibility

impairment at Class I areas outside the Colorado Plateau, and 2) the impacts of increases

in NOx emissions due to the oil and gas development activities. We previously

commented in a letter to you dated August 4, 2009, that we consider selective catalytic
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reduction (SCR) technology to be best available retrofit technology (BART) for several

Wyoming facilities that are subject to BART under the regional haze rule.

We look forward to your response, as per section 40 CFR 51.308(i)(3). For further

information regarding our comments, please contact Pat Brewer of the NPS Air

Resources Division at 303-969-2153, or Tim Allen of the FWS Branch of Air Quality at

303-914-3802.

Again, we appreciate the opportunity to work closely with the State of Wyoming and

compliment you on your hard work and dedication to significant improvement in our

nation's air quality values and visibility.

Sincerely,

J;:~ Chief, Air Resources Division

National Park Service

Enclosure

cc:

Callie Videtich

USEPA Region 8

1595 Wynkoop St.

Mail Code: 8P-AR

Denver, CO 80202-1129

Sincerely,

Sandra

~rktu V. Silva

Chief, Branch of Air Quality

U.S. Fish & Wildlife Service
National Park Service and U.S. Fish and Wildlife Service Comments

Wyoming Draft State Implementation Plan for Regional Haze

October 21, 2009

General Comments

Wyoming's draft State Implementation Plan (SIP) is well organized and addresses all the key

elements of a regional haze SIP as outlined in our August 2006 letter to the states. Wyoming

(WY) applies Western Regional Air Partnership (WRAP) teclmical analyses to define current

and natural visibility conditions, emissions inventories, state and source-sector contributions to

haze at WY Class I areas, and visibility response to expected emissions controls by 2018. These

WRAP products provide the basis for WY's reasonable progress goals. Beyond the emissions

reductions modeled by WRAP, WY documents additional nitrogen oxides (NOx) emissions

reductions from Best Available Retrofit Technology (BART) and WY's long-term strategy. We

are pleased with WY's commitment to these reductions and recommend that the State highlight

total expected reductions in a summary table and summary discussion early in the document.

We are concerned that WY has relied on sulfur dioxide (S02) controls under the Section 309

State Implementation Plan to also cover all WY's obligations for S02 under the Section 309(g)

SIP. The 309 SIP applied to Class I areas on the Colorado Plateau. Because Class I areas in

WYand neighboring states are not meeting the uniform rate of progress, WY should also

consider as part ofits reasonable progress analyses if additional S02 controls would be warranted

for Class I areas not on the Colorado Plateau.

We are also concerned by the projected increases by 2018 in NO" emissions from oil and gas

activities. Because these activities are located near the WY Class I areas, these emissions

increases may be offsetting the benefits of the significant NOx emissions reductions expected

from mobile and point sources distributed across the State. Several large oil and gas

development projects are being planned for southern and southwestern WY. Emissions from

these projects are likely not included in the WRAP Phase II projections. We recommend that

WY work closely with the oil and gas industry to improve the emission projections and to reduce

emissions gromh from these projects.

In our previous comments on WY's BART determinations (letter dated August 4, 2009), we

recommended that additional facilities could cost effectively utilize Selective Catalytic

Reduction technology to further reduce NO" emissions.
Specific Comments

Sections 2 and 3 effectively describe the WY Class I areas and the visibility monitoring data that

define the 20% worst and 20% best visibility days at these areas. The figures in Section 3 clearly

demonstrate that organic carbon matter is the largest contributor to light extinction on the 20%

worst days at the WY Class I areas and that sulfate (S04) is the second most important

contributor. Nitrate (NO]), elemental carbon, and coarse mass are smaller contributors on the

20% worst days. Sulfate and nitrate have larger percentage contributions on the 20% best days.

It would be helpful to include in Section 3 a brief discussion of how light extinction and

decivieware calculated from IMPROVE measurements. (This discussion is actually provided on

pages 191 and 192 in Section 13; it would be helpful to move it to the introductory discussion in

Section 3.)

Section 4: Emissions Inventory

WY could improve the reader's understanding of the subsequent chapters by providing

additional emissions inventory data. WY reports emissions as calculated by the WRAP for the

WRAP 2002d and 2018PRPb inventories. It would be helpful to add the inventory tables for

WRAP 2002c and 2018 PRPa inventories for S02 and NOx, and to explain that these are the

basis for the CAMx PSAT source apportionment runs that are used in Section 5 to define WY

contributions to S04 and NO] at WY Class I areas. WY should also clarify that the 2002d and

2018 PRPb inventories are used in the WRAP CMAQ projections of progress by 2018 that are

presented in Section 5. Table 4.9-1 does indicate the differences between the two inventories

and pg. 47 does cite that additional information on the inventories can be found in the WY

Technical Support Document. However, the inventories are so important to interpretation of

results in Section 5 that we recommend that WY provide the data in Section 4.

The majority of the NOx reductions projected for the 2018PRPb inventory (Table 4.3-1) are due

to reductions in the mobile omoad and nomoad sectors. Point source NOx reductions are roughly

7500 tons, while NOx emissions from oil and gas activities are projected to increase by 19,000

tons (132%). There is significant uncertainty in the oil and gas productions as WY is currently

reviewing proposals for several additional oil and gas projects that would increase emissions

beyond those estimated in the WRAP inventory.

Section 5: Source Apportionment and Regional Haze Modeling

WY cites WRAP CAMx-PSAT analyses of contributions to S04 and NO] from different source

regions and CMAQ projections of 2018 progress. The inventories and models are subtly

different so there are subtle differences in the results between CAMx-PSAT and CMAQ. PSAT

is suggesting small increases in WY's contributions to S04 (Figures 5.2.1-1 through 5.2.1-3) and

NO, (Figures 5.2.2-1 throngh 5.2.2-3) by 2018 on the 20% worst days at the WY Class I areas.

Referring back to the 2018PRPa S02 inventory, there is actually an increase in S02 emissions

from point sources that is revised for the WRAP 2018PRPb inventory to a decrease in S02 point

source emissions. PSAT points out the importance of location ofNOx emissions, particularly at

the Bridger Wilderness Area. Oil and gas NOx emissions increases are occurring in

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southwestern and central WY relatively near the WY Class I areas. NOx reductions from mobile

and point sources are more distributed across the state.

The Weighted Emissions Potential (WEP) analyses are appropriately presented and interpreted.

Organic carbon, elemental carbon, and particulate matter (PM) are important contributors to light

extinction, but nonMantbropogenic sources dominate and so WY has appropriately placed less

emphasis on these constituents in this SIP.

It would be helpful to discuss in Section 5 how relative response factors are calculated to project

future visibility.

CMAQ results indicate that extinction due to sulfate and nitrate will decrease slightly by 2018,

but the WY Class I areas will not achieve the uniform rate of progress.

As part of our ongoing consultation, on October 6, 2009, we consulted with WY staff by

teleconference. During our call, it became clear that WY is expecting NOx reductions by 2018

from BART and the long-term strategy that are not included in the WRAP PSAT source

apportionment and CMAQ modeling of progress by 2018. It is important to point this out in

Section 5 even if there are not modeling results to demonstrate the benefits of these additional

reductions.

Section 6: BART determination

NPS previously submitted comments that SCR would be cost effective as BART for NOx

emissions from additional BART-eligible Electric Generating Units (EGU). It would be helpful

to state at the end of the section the cumulative NOx reductions expected from BART

implementation in WY.

Table 6.2-1 compares actual S02 emissions to S02 milestone commitments in the Section 309

SIP. The state should clarify if actual emissions or milestone commitments are used in the

WRAP 2018PRPb S02 emissions inventory. Actual emissions are currently running much lower

than the milestone commitments.

Section 7: Reasonable Progress Goals

Section 7.5 (pg. 123) indicates that WY Reasonable Progress Goals (RPGs) for 20% Worst Days

and 20% Best Days for Wyoming Class I areas are based primarily on results of WRAP CMAQ

modeling for 2018. WY should clarify that RPGs listed in Table 7.5-1 are the results of WRAP

2018b modeling without any additional controls beyond WRAP 2018b modeling. Actual

reductions may be greater than those modeled.

Because the WY Class I areas do not achieve the uniform rate of progress, WY's reasonable

progress analysis needs to consider S02 controls for facilities not already addressed in WY's

Section 309 SIP. The S02 reductions in the 309 SIP do not exempt WY from considering in this

309(g) SIP how the emissions reductions expected from the 309 SIP controls, plus additional

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S02 controls, could be targeted to protect Class I areas that are not on the Colorado Plateau.

The State could find that additional S02 controls may not be warranted, but that finding must be

based on an assessment of the reasonable progress factors noted in the EPA regulations. In

Section 7.4 WY clarifies that the S02 reductions under the 309 SIP are included in the WRAP

modeling. WY should also define the tons ofS02reductions expected under the 309 SIP. Table

4.2-1 suggests a net reduction of 22,000 tons S02 from all point sources by 2018, but that figure

appears to include more sources than those controlling under the 309 SIP.

Table 7.2-1 is not cited in the text of Section 7.2.

WY uses Q/d::: 10 as an indicator ofsources that should be considered under reasonable progress

for additional NO" controls. Without more specific guidance from EPA, there is precedence that

other states have used a similar approach to screen sources. Applying these criteria, two units at

Dave Johnson EGU, one unit at the Mountain Cement plant, and oil and gas exploration and

production are identified for reasonable progress analyses. Highly cost effective NO" controls

were identified in all cases. The reader is referred to Section 8 to learn that WY does not have

regulatory authority to require controls on these sources. It would be helpful to provide this

information in Section 7 or at a minimum to refer the reader to the specific section (8.3.4) where

the outcome ofthe reasonable progress analyses is provided.

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 adopt cost effective

controls for reasonable progress for those pollutants which WY can control.

Section 8: Long Term Strategy

WY identifies contributions to Class I areas outside WYand contributions of neighboring states

to WY Class I areas. WY consulted with neighboring states through discussions in WRAP

workgroups. WY cites EPA efforts to address emissions from Canada, Mexico, and marine

shipping as evidence of progress on contributions from sources outside WY.

WY indicates that controls under Section 309 SIP will have greater benefit at WY Class I areas

than the Class I areas on the Colorado Plateau. Nonetheless, WY needs to consider what

additional S02 controls not considered in the 309 SIP are feasible for the WYand neighboring

Class I areas.

Oil and gas development and production are important and growing sources of NO" emissions in

WY. Therefore WY should work closely with the oil and gas industry to develop better

estimates of oil and gas NO" emissions growth. Projects currently under evaluation in southern

and southwestern WY (Pinedale, Hiawatha, Moxa Arch, Continental Divide-Creston, Gun

Barrel, Madden Deep, and Iron Horse) could significantly increase NO" emissions beyond those

already projected in the WRAP Phase II oil and gas inventory.

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While WY is developing the regulatory authority to limit emissions for oil and gas activities, we

encourage the State to ask industry to offset emissions prior to regulatory requirements. Ozone

nonattainment in the Sublette County area will require WY to develop NOx emissions reduction

strategies. Emissions offset requirements currently in place are a start.

Given that WY lacks regulatory authority for additional controls for non-BART sources, it is

important that WY revisit controls options in 2013.

Long-term control strategies at BART facilities are welcome. A table to support Figure 8.3.6·7

would be helpful to understand the magnitude of expected emissions reductions from BART

implementation and under the long-term strategy. The table provided by WY after our call was

very helpful in understanding the sources of emissions reductions.

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 encourage WY to also consider cost-effective controls for point source

emissions of fine particles, the anthropogenic contribution to dust (fine PM and course PM), and

prescribed fire.

We ask that WY include in the 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 look forward to continuing to work with WY to protect visibility and other air quality related

values in the Class I areas and the region.

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