Federal Register / Vol. 82, No. 170 / Tuesday, September 5, 2017 / Proposed Rules 41903 

Dated: August 22, 2017. 

Peter J. Brown, 

Rear Admiral, U.S. Coast Guard, Commander, 

Seventh Coast Guard District. 

[FR Doc. 2017–18711 Filed 9–1–17; 8:45 am] 

BILLING CODE 9110–04–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 81 

[EPA–HQ–OAR–2017–0003; FRL–9967–11– 

OAR] 

EPA Responses to Certain State 

Designation Recommendations for the 

2010 Sulfur Dioxide Primary National 

Ambient Air Quality Standard: 

Notification of Availability and Public 

Comment Period 

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 areaspecific technical support information 

at the following locations: 

Regional offices States 

Dave 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/sulfurdioxide-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. 

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41904 Federal Register / Vol. 82, No. 170 / Tuesday, September 5, 2017 / Proposed Rules 

1A 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. 

2A 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. 

3Sierra Club v. McCarthy, No. 3–13–cv–3953 (SI) 

(N.D. Cal. Mar. 2, 2015). 

4 In Mineral County, West Virginia, a new SO2

monitor was installed and is operated by the state 

of Maryland. 

5 40 CFR part 51, subpart BB (80 FR 51052; 

August 21, 2015). 

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/sulfurdioxide-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/sulfurdioxide-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 

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Federal Register / Vol. 82, No. 170 / Tuesday, September 5, 2017 / Proposed Rules 41905 

6See 75 FR 35520 at 35525, June 22, 2010. 

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-orimplementing-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-dioxidedesignations. 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 

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7This view was confirmed in Catawba County v. 

EPA, 571 F.3d 20 (D.C. Cir. 2009). 

8Tribes are invited to submit recommendations 

following promulgation of a new or revised 

NAAQS, but are not required to do so. 

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 

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Federal Register / Vol. 82, No. 170 / Tuesday, September 5, 2017 / Proposed Rules 41907 

9See, ‘‘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. 

10See, ‘‘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. 

11The 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. 

12See ‘‘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/ 

SO2lDRRlDesignationlModelinglClarification

lMemo-03082017.pdf. 

13The 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/tribespecific sections. For informational purposes, these 

individual state/territory/tribe-specific sections/ 

TSDs are available for separate downloading from 

the indicated EPA Web site. 

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 areaspecific 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/sulfurdioxide-designations. Area-specific 

questions can be addressed to the EPA 

Regional offices (see contact information 

provided at the beginning of this 

document). 

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41908 Federal Register / Vol. 82, No. 170 / Tuesday, September 5, 2017 / Proposed Rules 

Dated: August 22, 2017. 

Mary E. Henigin, 

Acting Director, Office of Air Quality Planning 

& Standards. 

[FR Doc. 2017–18423 Filed 9–1–17; 8:45 am] 

BILLING CODE 6560–50–P 

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