November 30, 2011

Lisa P. Jackson, Administrator U.S. Environmental Protection Agency

Mail Code: 6102T 1200 Pennsylvania Ave., NW Washington, DC 20460 Attention: Docket ID No. EPA-HQ-OAR-2010-1059

Re: Draft Guidance for 1-Hour SO 2 NAAQS SIP Submissions

Dear Administrator Jackson:

The Northeast States for Coordinated Air Use Manage ment (NESCAUM) offers the following comments on the U.S. Environmental Protection Agenc y’s (EPA’s) draft non-binding guidance,

entitled “Guidance for 1-Hour SO 2 NAAQS SIP Submissions,” as referenced in the Octob er 3, 2011 notice of availability published in the Federa l Register (76 FR 61098-61100). NESCAUM is the regional association of air pollution contro l agencies representing Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont.

The guidance is intended to assist state and tribal governments in preparing their 1-hour primary sulfur dioxide (SO 2 ) National Ambient Air Quality Standard (NAAQS) Sta te Implementation Plan (SIP) submittals, which are due June 3, 2013. While we appreciate EPA’s efforts to get guidance out in a timely manner, we are very concer ned with the SIP-related impacts, both statutory and workload-related, that appear to be a ssumed in the draft.

Areas designated as “unclassifiable” for SO 2 are required to develop and submit attainment SIPs within one year of designation. The workload burde n required for SIP development is significant and would require states to shift resou rces from other program areas in order to complete attainment SIPs and maintenance plans, due by June 2013, for all areas, including those that might be able to be classified as “attainment” under an extended designation timeline. States are concerned about their ability to complete their work within the prescribed deadlines, as well as consequences for late submittals. EPA should ex plore how it can best provide states that are diligently attempting to complete their work the ad equate time to do so.

To this end, we urge EPA to judiciously use the aut hority granted it under Section 107(d)(1)(B)(i) of the Clean Air Act by working clo sely with the states to determine where SO 2 designations should be delayed for one year, until June 2013. This would selectively target those

areas of a state where insufficient information exi sts to reasonably conclude there will be a nonattainment problem. The one-year extensions for these areas would:Draft Guidance for 1-Hour SO 2 NAAQS SIP Submissions Page 2

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(1) conserve scarce state resources by allowing them to focus the earliest modeling and planning efforts on those areas and sources most li kely to have or contribute to an SO 2 NAAQS problem; (2) allow states and EPA more time to generate and anal yze data to inform final designations in those areas likely attaining the SO 2 NAAQS; (3) provide states with additional time to complete the modeling and permit revisions necessary to demonstrate attainment with the SO 2 NAAQS in areas likely attaining, and; (4) help minimize – where warranted – the need for stat es and EPA to engage in time consuming and costly SIP development and processing associated with overly broad “unclassifiable” designations.

Such a selective approach under Section 107(d)(1)(B )(i) will allow states to more efficiently focus early planning efforts and limited resources where they are most needed, and avoid using staff resources on those areas likely attaining the standard. It will also help prevent shifting limited resources from other air quality planning e fforts, such as ground-level ozone – a significant regional concern in the Northeast. We believe this approach would allow states to work in a smarter, more streamlined approach consis tent with the Administration’s stated goal of reducing unnecessary regulatory burdens. It will a lso allow states to better allocate scarce resources, and focus early action on areas where it is most needed to protect public health.

The remainder of NESCAUM’s comments focuses on the need for EPA to clarify key statements and requirements in the guidance. The sections and page numbers referenced below correspond with those in the Public Review Draft of the guidan ce, dated September 22, 2011, which was

available on EPA’s website at: http://www.epa.gov/oaqps001/sulfurdioxide/implement .html

.

Section IV. Section 110(a)(1) and (2) NAAQS mainten ance/infrastructure elements

Comment: The two statements in the draft guidance listed bel ow should be revised to explicitly indicate whether the 100 tons per year ( tpy) threshold corresponds to actual or

allowable emissions.

Page 9: “We expect that states would focus perform ance of attainment demonstration modeling on areas with larger sources (e.g., those source emitting over 100 tons per year (tpy) of SO 2 ), and any other sources that we anticipate to caus e or contribute to a violation to determine compliance with the new SO 2 NAAQS.”

Page 10: “EPA believes it is reasonable to expect states to demonstrate, at a minimum, that major SO 2 sources ( ≥ 100 tpy) are not causing or contributing to violat ions of the 1-

hour SO 2 NAAQS.”

Comment: Footnote 7 on Page 9 should be revised to the follo wing (revised wording is in italics): “In cases where large sources of SO 2 emissions are located on the borders of the other states, the states should coordinate the modeling methodolo gy applied and theDraft Guidance for 1-Hour SO 2 NAAQS SIP Submissions Page 3

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modeling inputs with each other during the development of the SIP submittals for t he

affected areas (i.e., before the modeling is submitted to EPA) .”

Section IV(B)(2)(a) Section 110(a)(1) SIPs: Mainten ance demonstration: Refined dispersion modeling

Comment: Pages 16-17. This section suggests that states fo cus on those sources emitting more than 100 tpy of actual emissions. If a state w ere to base its approach on actual emissions, does EPA have a preferred method for cal culating actual emissions? For example, the method could be based on an average of the last three years of available emissions data, the average of the last two years o f available data, the latest year of available data (representing normal operating conditions), or the highest annual emissions reported in the last three years.

Section IV(B)(3)(b) Section 110(a)(1) SIPs: Control strategy: SO 2 limits for sources using

control measures to meet the Cross-state Air Pollu tion Rule and MACT rules

Comment: Pages 21-23. This section states that many source s will be installing SO 2 add-on

controls due to the Cross-State Air Pollution Rule or the Utility MACT standards and that

there is a need to establish enforceable 1-hour SO 2 emission limits on these specific sources. This raises a broader issue applicable to all sourc es that could potentially require modeling for the purposes of determining compliance with SO 2 NAAQS, i.e., if a source does not have

a 1-hour SO 2 emission limit, is it acceptable to use a longer t erm emission limit to represent

the source’s 1-hour limit?

For example, a large, existing source may have a 24 -hour and an annual SO 2 emission limit, but no 1-hour emission limit. Would it be acceptab le to use the 24-hour emission limit in the

1-hour SO 2 NAAQS modeling, or would the facility’s permit nee d to be modified so that

there is a 1-hour emission limit to use in the 1-ho ur SO 2 NAAQS modeling?

Appendix A, Section 5.1 Determining sources to mode l

Comment: The draft guidance has no requirement if a source with allowable SO 2 emissions above 100 tpy is not included in a state’s SIP mode ling. EPA should require the state to provide some type of justification on why it was no t modeled (e.g., very low actual emissions, high stacks, or future control anticipat ed).

Comment: When modeling a facility with multiple SO 2 emission points, such as an oil refinery or a glass plant, is there an hourly emiss ion rate that the state can consider “de minimus” and, therefore, not include in the modelin g? If such guidance is provided, we

recommend it should be made a function of stack hei ght. Example criteria would be to include the following in the modeling:Draft Guidance for 1-Hour SO 2 NAAQS SIP Submissions Page 4

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a) 2.5 lbs/hr or more with a stack height greater than 50 ft,

b) 0.7 lbs/hr or more with a stack height between 20 a nd 50 ft,

c) 0.3 lbs/hr or more with a stack height less than 20 ft.

Appendix A, Section 6.3 Good Engineering Practice ( GEP) stack height

Comment: When building dimensions are input into the current version of AERMOD, the increased turbulence from building downwash effects is incorporated into the plume’s dispersion, even when a stack is at its GEP stack h eight. It is unclear in the draft guidance whether building dimensions need to be input into A ERMOD for stacks with a height

considered to be GEP. This needs clarification.

Appendix A, Section 6.6 Urban/rural determination

Comment: EPA should revise the beginning of the second parag raph in this section to read as follows (changes are in italics): “In addition, special emphasis must be placed in making accurate land use classification determinations for regulatory SO 2 modeling. Topographic maps may not provide current representative land us e classification. Therefore, physical surveying as well as the study of current aerial ph otos may be incorporated into this process.

For SO 2 modeling, the urban/rural determination is of great importance because AERMOD

invokes a 4-hour half life for urban SO 2 sources.”

Thank you for the opportunity to comment. If you o r your staff has any questions regarding the issues raised in this letter, please contact Laura Shields at NESCAUM at 617-259-2084.

Sincerely,

Arthur N. Marin

Executive Director

Cc: NESCAUM Directors Gina McCarthy, EPA/OAR Mary Henigin, EPA/OAQPS Anna Wood, EPA/OAQPS Scott Mathias, EPA/OAQPS Larry Wallace, EPA/OAQPS David Conroy, EPA Region 1 William S. Baker, EPA Region 2