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 Environmental Protection Agency 40 CFR Part 81
[EPA-HQ-OAR-2017-0003; FRL-9967-11-OAR]
 AGENCY: Environmental Protection Agency (EPA).
 ACTION: Notification of availability and public comment period.
 SUMMARY: Notice is hereby given that the Environmental Protection Agency (EPA) has posted on our public electronic docket and Internet Web site responses to certain state designation recommendations for the 2010 Sulfur Dioxide (SO2) Primary National Ambient Air Quality Standard (NAAQS). These responses include our intended designations for the affected areas. The EPA invites the public to review and provide input on our intended designations during the comment period specified in the 
                        **DATES**
                         section. The EPA sent our responses directly to the states on or about August 22, 2017. The EPA intends to make final designation determinations for the areas of the country addressed by these responses no later than December 31, 2017.
 DATES: Comments must be received on or before October 5, 2017. Please refer to 
                        **SUPPLEMENTARY INFORMATION**
                         for additional information on the comment period.
 ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2017-0003, at 
                        *http://www.regulations.gov.*
                         Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from regulations.gov. The EPA may publish any comment received to our public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (
                        *i.e.,*
                         on the Web, Cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit 
                        *https://www2.epa.gov/​dockets/​commenting-epa-dockets.* The public may inspect the recommendations from the states and territories, our recent letters notifying the affected states, territories, and tribes of our intended designations, and area-specific technical support information at the following locations: Regional offices
StatesDave Conroy, Chief, Air Programs Branch, EPA New England, 1 Congress Street, Suite 1100, Boston, MA 02114-2023, (617) 918-1661
Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont.Richard Ruvo, Chief, Air Programs Branch, EPA Region II, 290 Broadway, 25th Floor, New York, NY 10007-1866, (212) 637-4014
New Jersey, New York, Puerto Rico, and Virgin Islands.Cynthia H. Stahl, Acting Associate Director, Office of Air Program Planning, EPA Region III, 1650 Arch Street, Philadelphia, PA 19103-2187, (215) 814-2180
Delaware, District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia.R. Scott Davis, Chief, Air Planning Branch, EPA Region IV, Sam Nunn Atlanta Federal Center, 61 Forsyth Street SW., 12th Floor, Atlanta, GA 30303, (404) 562-9127
Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee.John Mooney, Chief, Air Programs Branch, EPA Region V, 77 West Jackson Street, Chicago, IL 60604, (312) 886-6043
Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin.Alan Shar, Acting Chief, Air Planning Section, EPA Region VI, 1445 Ross Avenue, Dallas, TX 75202, (214) 665-6691
Arkansas, Louisiana, New Mexico, Oklahoma, and Texas.Mike Jay, Chief, Air Programs Branch, EPA Region VII, 11201 Renner Blvd., Lenexa, KS 66129, (913) 551-7460
Iowa, Kansas, Missouri, and Nebraska.Monica Morales, Air Program Director, EPA Region VIII, 1595 Wynkoop Street, Denver, CO 80202-1129, (303) 312-6936
Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming.Doris Lo, Air Planning Office, EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105, (415) 972-3959
American Samoa, Arizona, California, Guam, Hawaii, Nevada, Northern Mariana Islands, Navajo Nation, and the Hopi Tribe.Debra Suzuki, Manager, State and Tribal Air Programs, EPA Region X, Office of Air, Waste, and Toxics, Mail Code OAQ-107, 1200 Sixth Avenue, Seattle, WA 98101, (206) 553-0985
Alaska, Idaho, Oregon, and Washington.
 The information can also be reviewed online at 
                    *https://www.epa.gov/​sulfur-dioxide-designations*
                     and also in the public docket for these SO2
                     designations at 
                    *https://www.regulations.gov*
                     under Docket ID No. EPA-HQ-OAR-2017-0003.
 FOR FURTHER INFORMATION CONTACT: For general questions concerning this action, please contact Liz Etchells, U.S. EPA, Office of Air Quality Planning and Standards, Air Quality Policy Division, C539-01, Research Triangle Park, NC 27709, telephone (919) 541-0253, email at 
                        *etchells.elizabeth@epa.gov.*
                         The following EPA contacts can answer questions regarding areas in a particular EPA Regional office: U.S. EPA Regional Office Contacts Region I—Leiran Biton, telephone (617) 918-1267, email at 
                        *biton.leiran@epa.gov.* Region II—Ken Fradkin, telephone (212) 637-3702, email at 
                        *fradkin.kenneth@epa.gov.* Region III—Ruth Knapp, telephone (215) 814-2191, email at 
                        *knapp.ruth@epa.gov*. Region IV—Twunjala Bradley, telephone (404) 562-9352, email at 
                        *bradley.twunjala@epa.gov*. Region V—John Summerhays, telephone (312) 886-6067, email at 
                        *summerhays.john@epa.gov*.
                        ( print page 41904) Region VI—Dayana Medina, telephone (214) 665-7241, email at 
                        *medina.dayana@epa.gov*. Region VII—David Peter, telephone (913) 551-7397, email at
                        *peter.david@epa.gov*. Region VIII—Adam Clark, telephone (303) 312-7104, email at 
                        *clark.adam@epa.gov*. Region IX—Anita Lee, telephone (415) 972-3958, email at 
                        *lee.anita@epa.gov*. Region X—John Chi, telephone (206) 553-1185, email at 
                        *chi.john@epa.gov*.


SUPPLEMENTARY INFORMATION: Table of Contents The following is an outline of the Preamble. I. What is the purpose of this action? II. Instructions for Submitting Public Comments and Internet Web Site for Rulemaking Information III. What is the 2010 SO2 NAAQS and what are the health concerns that it addresses? IV. What are the CAA requirements for air quality designations and what action has the EPA taken to meet these requirements? V. What guidance has the EPA previously issue and how does the EPA now intend to apply the statutory requirements to determine area designations and boundaries? VI. What air quality information has the EPA used for these intended designations? VII. How do the Round 3 designations affect Indian country? VIII. Where can I find information forming the basis for the EPA's intended rule and exchanges between the EPA, states, and tribes related to this intended rule? I. What is the purpose of this action? The purpose of this action of availability is to solicit input from interested parties other than states on the EPA's recent responses to the state designation recommendations for the 2010 SO2
                     NAAQS. These responses, and their supporting technical analyses, can be found at 
                    *https://www.epa.gov/​sulfur-dioxide-designations*
                     and also in the public docket for these SO2
                     designations at 
                    *https://www.regulations.gov*
                     under Docket ID No. EPA-HQ-OAR-2017-0003. On June 2, 2010, the EPA Administrator signed a notice of final rulemaking that revised the primary SO2
                     NAAQS (75 FR 35520; June 22, 2010) after review of the existing primary SO2
                     standards promulgated on April 30, 1971 (36 FR 8187). The EPA established the revised primary SO2
                     NAAQS at 75 parts per billion (ppb) which is attained when the 3-year average of the annual 99th percentile of 1-hour daily maximum concentrations does not exceed 75 ppb. The process for designating areas following promulgation of a new or revised NAAQS is contained in the Clean Air Act (CAA or Act) section 107(d) (42 U.S.C. 7407). After promulgation of a new or revised NAAQS, each governor or tribal leader has an opportunity to recommend air quality designations, including the appropriate boundaries for nonattainment areas, to the EPA. The EPA considers these recommendations as part of its duty to promulgate the formal area designations and boundaries for the new or revised NAAQS. By no later than 120 days prior to promulgating designations, the EPA is required to notify states, territories, and tribes, as appropriate, of any intended modifications to an area designation or boundary recommendation that the EPA deems necessary. After invoking a 1-year extension of the deadlines to designate areas, as provided for in section 107 of the Act, the EPA completed an initial round of SO2
                     designations for certain areas of the country on July 25, 2013 (referred to as “Round 1”).[1]
                    
                     Following the initial designations, three lawsuits were filed against the EPA in different U.S. District Courts, alleging the agency had failed to perform a nondiscretionary duty under the CAA by not designating all portions of the country by the June 2, 2013, deadline. In one of those cases, the U.S. District Court for the Northern District of California on March 2, 2015, entered an enforceable order for the EPA to complete the area designations by three specific deadlines according to the court-ordered schedule. To meet the first court-ordered deadline, additional areas were designated on June 30, 2016, and November 29, 2016 (collectively referred to as “Round 2”).[2]
                    
                     Pursuant to the court-ordered schedule,[3]
                    
                     the EPA must complete SO2
                     designations for the remaining areas of the country by two specific deadlines: December 31, 2017, and December 31, 2020. This current third round of designations addresses all remaining undesignated areas except those where a state [4]
                    
                     has installed and begun timely operating a new SO2
                     monitoring network meeting EPA specifications referenced in EPA's SO2
                     Data Requirements Rule.[5] On or about August 22, 2017, consistent with section 107(d)(1)(b)(ii) of the CAA, the EPA notified affected states, territories, and tribes of our assessment of their recommended designations for Round 3. While we are in agreement with the recommendations for many areas, some warrant further discussion. We stand ready to assist and hope to resolve any differences regarding the proper designation for these areas within the 120-day process provided by the CAA. For any areas that we designate nonattainment in our final action, the CAA directs states to develop and submit to the EPA State Implementation Plans (SIPs) within 18 months of the effective date of the final rule, that meet the requirements of sections 172(c) and 191-192 of the CAA and provide for attainment of the NAAQS as expeditiously as practicable, but not later than 5 years from the effective date of the final rule. II. Instructions for Submitting Public Comments and Internet Web Site for Rulemaking Information A. Invitation To Comment The purpose of this action is to solicit input from interested parties, other than the states, territories, and tribes to which we have sent notification letters, on the EPA's recent responses to the designation recommendations for the 2010 SO2
                     NAAQS. These responses, and their supporting technical analyses, can be found at 
                    *https://www.epa.gov/​sulfur-dioxide-designations*
                     and also in the public docket for these SO2
                     designations at Docket ID No. EPA-HQ-OAR-2017-0003. Air dispersion modeling input and output files are too large to post in the docket or on the Web site and must be requested from the EPA Docket Office or the Regional office contacts listed in the beginning of this document. The EPA Docket Office can be contacted at (202) 566-1744, and is located at EPA Docket Center Reading Room, WJC West Building, Room 3334, 1301 Constitution Avenue NW., Washington, DC 20004. The hours of operation at the EPA Docket Center are 8:30 a.m.-4:30 p.m., Monday-Friday. CAA section 107(d) provides a process for air quality designations that 
                    ( print page 41905)
                    involves recommendations by states, territories, and tribes to the EPA and responses from the EPA to those parties, prior to the EPA promulgating final area designations and boundaries. The EPA is not required under the CAA section 107(d) to seek public comment during the designation process, but we are electing to do so for these areas with respect to the 2010 SO2
                     NAAQS in order to gather additional information for the EPA to consider before making final designations for the specific areas addressed in the EPA's recent letters to states, territories, and tribes. The EPA invites public input on our responses to states regarding these areas during the 30-day comment period provided in this action. In order to receive full consideration, input from the public must be submitted to the docket by October 5, 2017. At this time, the EPA is not asking for public comments on areas beyond those areas that are the subject of this proposed action. This action and opportunity for public comment does not affect any rights or obligations of any state, territory, or tribe, or of the EPA, which might otherwise exist pursuant to the CAA section 107(d). Please refer to the 
                    **ADDRESSES**
                     section in this document for specific instructions on submitting comments and locating relevant public documents. For some cases, the EPA has indicated to a state or territory that further discussion is needed—
                    *e.g.,*
                     where the state recommended a designation of unclassifiable/attainment (or unclassifiable) and available air quality monitoring or modeling data show that the area may be violating the 2010 primary SO2
                     NAAQS or contain sources that may be contributing to air quality in a nearby area that may be violating the 2010 primary SO2
                     NAAQS. In establishing nonattainment area boundaries for a particular area, the EPA is required to include within the boundaries both the area that does not meet the standard and any nearby area contributing to the area that does not meet the standard. We are particularly interested in receiving comments, supported by relevant information, if you believe that a specific geographic area for which further discussion is needed concerning a state's recommended designation of unclassifiable/attainment or unclassifiable (and for which available air quality data would require a modification of the recommended designation) should not be categorized by the CAA section 107(d) criteria as nonattainment, or if you believe that a specific nearby area for which the EPA does agree with a state's recommended designation of unclassifiable/attainment or unclassifiable should in fact be categorized as contributing to nonattainment using the CAA section 107(d) criteria. Please be as specific as possible in supporting your views. Describe any assumptions and provide any technical information and/or data that you used.
                Provide specific examples to illustrate your concerns, and suggest alternatives.
                Explain your views as clearly as possible.
                Provide your input by the comment period deadline identified. The EPA intends to complete designations for the areas subject to this round no later than December 31, 2017. The EPA is not yet prepared to respond to state and tribal area designation recommendations, or seek public input thereon, for areas that will be designated in Round 4 for the 2010 SO2
                     NAAQS. The EPA is required to address those areas by December 31, 2020. Additional information on the EPA's intended approach for addressing designations for all areas can be found on the EPA's SO2
                     implementation Web site at 
                    *https://www.epa.gov/​so2-pollution/​applying-or-implementing-sulfur-dioxide-standards.* B. What should I consider as I prepare my comments for the EPA? 1. 
                    *Submitting CBI.*
                     Do not submit CBI information to the EPA through 
                    *https://www.regulations.gov*
                     or email. Clearly mark the part or all of the information that you claim to be CBI. For CBI in a disk or CD ROM that you mail to the EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 Code of Federal Regulations (CFR) part 2. Send or deliver information identified as CBI only to the following address: Tiffany Purifoy, OAQPS CBI Officer, U.S. EPA, Office of Air Quality Planning and Standards, Mail Code C404-02, Research Triangle Park, NC 27711, telephone (919) 541-0878, email at 
                    *purifoy.tiffany@epa.gov,*
                     Attention Docket ID No. EPA-HQ-OAR-2017-0003. 2. 
                    *Tips for Preparing Your Comments.*
                     When submitting comments, remember to: Identify the rulemaking by docket number and other identifying information (subject heading,**Federal Register**
                     date and page number).
                Follow directions.
                Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes. C. Where can I find additional information for this rulemaking? The EPA has also established a Web site for this rulemaking at 
                    *https://www.epa.gov/​sulfur-dioxide-designations.*
                     The Web site includes the state, territorial and tribal recommendations, the EPA's intended area designations, information supporting the EPA's preliminary designation decisions, as well as the rulemaking actions and other related information that the public may find useful. III. What is the 2010 SO2
                     NAAQS and what are the health concerns that it addresses? The Administrator signed a final rule revising the primary SO2
                     NAAQS on June 2, 2010. The rule was published in the 
                    **Federal Register**
                     on June 22, 2010 (75 FR 35520) and became effective on August 23, 2010. Specifically, the EPA established a new 1-hour SO2
                     standard at a level of 75 ppb, which is met at an ambient air quality monitoring site when the 3-year average of the annual 99th percentile of 1-hour daily maximum concentrations is less than or equal to 75 ppb, as determined in accordance with Appendix T of 40 CFR part 50. 40 CFR 50.17(a) and (b). Current scientific evidence links short-term exposures to SO2
                    , ranging from 5 minutes to 24 hours, with an array of adverse respiratory effects including bronchoconstriction and increased asthma symptoms. Studies also show a connection between short-term exposure and increased visits to emergency departments and hospital admissions for respiratory illnesses, particularly in at-risk populations including children, the elderly, and asthmatics.[6] IV. What are the CAA requirements for air quality designations and what action has the EPA taken to meet these requirements? After the EPA promulgates a new or revised NAAQS, the EPA is required to designate all areas of the country as either “nonattainment,” “attainment,” or “unclassifiable,” for that NAAQS pursuant to section 107(d)(1) of the CAA. As part of these Round 3 
                    ( print page 41906)
                    designations, EPA is implementing its interpretation of statutory terms under CAA section 107(d) nationwide and is basing these designations on EPA's nationwide analytical approach and technical analysis, including evaluation of monitoring data and air quality modeling, applied to the available evidence for each area. Regarding statutory definitions and the EPA's interpretations of such, the section 107(d)(1)(A)(i) of the CAA defines a nonattainment area as an area that does not meet the NAAQS or that contributes to a nearby area that does not meet the NAAQS. An attainment area is defined by the CAA as any area that meets the NAAQS and does not contribute to a nearby area that does not meet the NAAQS. Unclassifiable areas are defined by the CAA as those that cannot be classified on the basis of available information as meeting or not meeting the NAAQS. In this action, the EPA defines a nonattainment area as an area that the EPA has determined violates the 2010 SO2
                     NAAQS or contributes to a violation in a nearby area, based on the most recent 3 years of air quality monitoring data, appropriate dispersion modeling analysis, and any other relevant information. In this action, an unclassifiable/attainment area is defined by EPA as an area that either: (1) Based on available information including (but not limited to) appropriate modeling analyses and/or monitoring data, EPA has determined (i) meets the 2010 SO2
                     NAAQS, and (ii) does not contribute to ambient air quality in a nearby area that does not meet the NAAQS; or (2) was not required to be characterized under 40 CFR 51.1203(c) or (d) and EPA does not have available information including (but not limited to) appropriate modeling analyses and/or monitoring data that suggests that the area may (i) not be meeting the NAAQS, or (ii) contribute to ambient air quality in a nearby area that does not meet the NAAQS. In this action, an unclassifiable area is defined by the EPA as an area that either: (1) Was required to be characterized by the state under 40 CFR 51.1203(c) or (d), has not been previously designated, and on the basis of available information cannot be classified as either: (i) Meeting or not meeting the 2010 SO2
                     NAAQS, or (ii) contributing or not contributing to ambient air quality in a nearby area that does not meet the NAAQS; or (2) was not required to be characterized under 40 CFR 51.1203(c) or (d) and the EPA does have available information including (but not limited to) appropriate modeling analyses and/or monitoring data that suggests that the area may (i) not be meeting the NAAQS, or (ii) contribute to ambient air quality in a nearby area that does not meet the NAAQS. These definitions refer to 40 CFR 51.1203(c) and (d), which are part of EPA's Data Requirements Rule. The citation to these CFR sections is in effect a reference to any area that contains a source, generally one emitting more than 2,000 tons per year of SO2
                     or was otherwise listed under the DRR, with respect to which the state has indicated that it will comply with the Data Requirements Rule either by establishing a new monitoring network or by submitting an air quality modeling analysis. This nationwide analytical approach also includes but is not limited to: (1) EPA's interpretations of other terms in the context of Round 3 of the 2010 SO2
                     NAAQS; (2) the appropriate basis for characterizing the air quality of an area; (3) the five-factor analysis to determine the boundaries for each air quality area under the NAAQS; and (4) the methodology for appropriately characterizing SO2
                     air quality through monitoring or modeling. The EPA notes that CAA section 107(d) provides the agency with discretion to determine how best to interpret the terms in the definition of a nonattainment area (
                    *e.g.,*
                     “contributes to” and “nearby”) for a new or revised NAAQS, given considerations such as the nature of a specific pollutant, the types of sources that may contribute to violations, the form of the standards for the pollutant, and other relevant information. In particular, the EPA's position is that the statute does not require the agency to establish bright line tests or thresholds for what constitutes “contribution” or “nearby” for purposes of designations.[7] Similarly, the EPA's position is that the statute permits the EPA to evaluate the appropriate application of the term “area” to include geographic areas based upon full or partial county boundaries, as may be appropriate for a particular NAAQS. For example, CAA section 107(d)(1)(B)(ii) explicitly provides that the EPA can make modifications to designation recommendations for an area “or portions thereof,” and under CAA section 107(d)(1)(B)(iv) a designation remains in effect for an area “or portion thereof” until the EPA redesignates it. By no later than 1 year after the promulgation of a new or revised NAAQS, CAA section 107(d)(1)(A) provides that each state governor is required to recommend air quality designations, including the appropriate boundaries for areas, to the EPA.[8]
                    
                     The EPA reviews those recommendations and is authorized to make any modifications the Administrator deems necessary. The statute does not define the term “necessary,” but the EPA interprets this to authorize the Administrator to modify designations that did not meet the statutory requirements or were otherwise inconsistent with the facts or analysis deemed appropriate by the Administrator. If the EPA is considering modifications to a recommendation, we are required by CAA section 107(d)(1)(B)(ii) to notify the state of any such intended modifications not less than 120 days prior to our promulgation of the final designation. These notifications are commonly known as the “120-day letters.” During this period, if the state or territory does not agree with the EPA's modification, it has an opportunity to respond to the EPA and to demonstrate why it believes the modification proposed by the EPA is inappropriate. If a state or territory fails to provide any recommendation for an area, in whole or in part, the EPA still must promulgate a designation that the Administrator deems appropriate, pursuant to CAA section 107(d)(1)(B)(ii). While CAA section 107(d) specifically addresses the designations process between the EPA and states and territories, the EPA intends to follow the same process to the extent practicable for tribes that submitted designation recommendations. V. What guidance has the EPA previously issued and how does the EPA now intend to apply the statutory requirements to determine area designations and boundaries? In the notice of proposed rulemaking for the revised SO2
                     NAAQS (74 FR 64810; December 8, 2009), the EPA issued proposed guidance on our approach to implementing the standard, including our approach to initial area designations. The EPA solicited comment on that guidance and, in the notice of final rulemaking (75 FR 35520; June 22, 2010), provided further guidance concerning implementation of the standard and how to identify nonattainment areas and boundaries for the SO2
                     NAAQS. Subsequently, on March 24, 2011, the EPA provided additional designations guidance to assist states with making their 
                    ( print page 41907)
                    recommendations for area designations and boundaries.[9]
                    
                     That guidance recommended, among other things, that monitoring data from the most recent 3 consecutive years be used to identify a violation of the SO2
                     NAAQS. This is appropriate because the form of the SO2
                     NAAQS is calculated as a 3-year average of the 99th percentile of the yearly distribution of 1-hour daily maximum SO2
                     concentrations (specifically the most recent 3 consecutive years). The EPA based the first round of final SO2
                     designations in 2013 solely on violating monitored SO2
                     concentrations for the years 2010-2012 from Federal Reference Method and Federal Equivalent Method monitors that are sited and operated in accordance with 40 CFR parts 50 and 58, and did not at that time designate any other areas. In the March 24, 2011, guidance, the EPA stated that the perimeter of a county containing a violating monitor would be the initial presumptive boundary for nonattainment areas, but also stated that the state, tribe and/or the EPA could conduct additional area-specific analyses that could justify establishing either a larger or smaller area. The EPA indicated that the following factors should be considered in an analysis of whether to exclude portions of a county and whether to include additional nearby areas outside the county as part of the designated nonattainment area: (1) Air quality data; (2) emissions-related data; (3) meteorology; (4) geography/topography; and (5) jurisdictional boundaries, as well as other available data. States and tribes may identify and evaluate other relevant factors or circumstances specific to a particular area. Following entry of the March 2, 2015, court order setting forth the schedule for the EPA to complete SO2
                     designations, the EPA issued updated designations guidance.[10]
                    
                     This guidance superseded the March 24, 2011, designation guidance for the 2010 SO2
                     NAAQS, and identified factors that the EPA intended to evaluate in determining whether areas are in violation of the 2010 SO2
                     NAAQS or contribute to air quality in nearby areas that are in violation of the 2010 SO2
                     NAAQS. The guidance also contained the factors the EPA intended to evaluate in determining the boundaries for all remaining areas in the country, consistent with the court's order and schedule. These factors include: (1) Air quality characterization via ambient monitoring or dispersion modeling results; (2) emissions-related data; (3) meteorology; (4) geography and topography; and (5) jurisdictional boundaries.[11] On March 8, 2017, the EPA issued a memo to clarify what version of the AERMOD modeling system is the most appropriate for consideration by the agency in the SO2
                     designations process.[12] VI. What air quality information has the EPA used for these intended designations? For designations for the SO2
                     NAAQS, air agencies have the flexibility to characterize air quality using either appropriately sited ambient air quality monitors or modeling of actual or allowable source emissions. These intended designations are based on the EPA's application of the nationwide analytical approach to, and preliminary technical assessment of, the weight of evidence for each area, including but not limited to available air quality monitoring data and air quality modeling results. With respect to air quality monitoring data, the EPA has considered data from at least the most recent 3 calendar years, 
                    *i.e.,*
                     2014-2016, as available. In most of the modeling runs available for EPA's review, the impacts of the actual emissions for one or more of the 3-year periods 2012-2014, 2013-2015, or 2014-2016 were considered, and in some cases the modeling was of recently effective or not-yet-effective limits on allowable emissions in lieu of or as a supplement to modeling of actual emissions. The 1-hour primary SO2
                     standard is violated at an ambient air quality monitoring site (or in the case of dispersion modeling, at an ambient air quality receptor location) when the 3-year average of the annual 99th percentile of the daily maximum 1-hour average concentrations exceeds 75 ppb, as determined in accordance with Appendix T of 40 CFR part 50. VII. How do the Round 3 designations affect Indian country? For areas of Indian country, there are no violating monitors. The Navajo Nation submitted modeling analyses for the areas around two SO2
                     emission sources located in the Navajo Nation, the Navajo Generating Station and the Four Corners Power Plant, neither of which indicated a violation of the NAAQS. The Navajo Nation and the lands of the Hopi Tribe are being designated as separate areas. No areas of Indian country are being designated as nonattainment as part of this round. Any other parts of Indian country being designated as unclassifiable/attainment or unclassifiable are being designated along with the surrounding state area. VIII. Where can I find information forming the basis for this intended rule and exchanges between the EPA, states, and tribes related to this intended rule? Information providing the basis for this intended action are provided in a technical support document (TSD) [13]
                    
                     included in the docket. The TSD, modeling files, technical assistance documents, applicable EPA guidance memoranda, and copies of correspondence regarding this process between the EPA and the states, territories, tribes, and other parties, are available for review at the public docket for these SO2
                     designations at 
                    *https://www.regulations.gov*
                     under Docket ID No. EPA-HQ-OAR-2017-0003, at the EPA Docket Center listed in the 
                    **ADDRESSES**
                     section of this document and on the agency's SO2
                     Designations Web site at 
                    *https://www.epa.gov/​sulfur-dioxide-designations.*
                     Area-specific questions can be addressed to the EPA Regional offices (
                    *see*
                     contact information provided at the beginning of this document). Dated: August 22, 2017. Mary E. Henigin, Acting Director, Office of Air Quality Planning & Standards.


# Footnotes

1.
    
                         A total of 29 areas throughout the U.S. were designated in this action published on August 5, 2013 (78 FR 47191). The EPA designated all 29 areas nonattainment based on violating monitored SO2
                         concentrations from Federal Reference Method and Federal Equivalent Method monitors that are sited and operated in accordance with 40 CFR parts 50 and 58, and did not at that time designate any other areas. Back to Citation
 2.
    
                         A total of 65 areas throughout the U.S. were designated in these actions published on July 12, 2016 (81 FR 45039), and December 13, 2016 (81 FR 89870). Of these 65 areas, seven were designated nonattainment. Back to Citation
 3.
    
                         
                        *Sierra Club*
                         v. 
                        *McCarthy,*
                         No. 3-13-cv-3953 (SI) (N.D. Cal. Mar. 2, 2015). Back to Citation
 4.
    
                         In Mineral County, West Virginia, a new SO2
                         monitor was installed and is operated by the state of Maryland. Back to Citation
 5.
    
                         40 CFR part 51, subpart BB (80 FR 51052; August 21, 2015). Back to Citation
 6.
    
                         
                        *See*75 FR 35520 at 35525, June 22, 2010. Back to Citation
 7.
    
                         This view was confirmed in 
                        *Catawba County*
                         v. 
                        *EPA,*
                         571 F.3d 20 (D.C. Cir. 2009). Back to Citation
 8.
    
                         Tribes are invited to submit recommendations following promulgation of a new or revised NAAQS, but are not required to do so. Back to Citation
 9.
    
                         
                        *See,*
                         “Area Designations for the 2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standards,” memorandum to Regional Air Division Directors, Regions I-X, from Stephen D. Page, dated March 24, 2011. Back to Citation
 10.
    
                         
                        *See,*
                         “Updated Guidance for Area Designations for the 2010 Primary Sulfur Dioxide National Ambient Air Quality Standard,” memorandum to Regional Air Division Directors, Regions I-X, from Stephen D. Page, dated March 20, 2015. Back to Citation
 11.
    
                         The EPA supplemented this guidance with documents first made available to states and other interested parties in 2013 and updated in 2016. 
                        *See*
                         SO2
                         NAAQS Designations Source-Oriented Monitoring Technical Assistance Document (February 2016), available at 
                        *https://www.epa.gov/​sites/​production/​files/​2016-06/​documents/​so2monitoringtad.pdf,*
                         and SO2
                         NAAQS Designations Modeling Technical Assistance Document (August 2016), available at 
                        *https://www.epa.gov/​sites/​production/​files/​2016-06/​documents/​so2modelingtad.pdf*. Back to Citation
 12.
    
                         
                        *See*
                         “Clarification on the AERMOD Modeling System Version for Use in SO2
                         Implementation Efforts and Other Regulatory Actions,” memorandum to EPA Regional Air Division Directors from Richard A. Wayland, dated March 8, 2017. This memo is available at 
                        *https://www3.epa.gov/​ttn/​scram/​guidance/​clarification/​SO**2**_DRR_Designation_Modeling_Clarification_Memo-03082017.pdf*. Back to Citation
 13.
    
                         The single TSD for this action consists of a few sections with information that applies to all affected areas or to certain groups of areas with some common features, and many sections that are specific to individual states, territories, or tribal areas. For convenience, the term “TSD” is also used generically to refer to these state/territory/tribe-specific sections. For informational purposes, these individual state/territory/tribe-specific sections/TSDs are available for separate downloading from the indicated EPA Web site. Back to Citation


[FR Doc. 2017-18423 Filed 9-1-17; 8:45 am] BILLING CODE 6560-50-P