The EPA Region 9 Regional Administrator, Jared Blumenfeld, signed the following proposed rule on 3/14/2014, and EPA is submitting it for 

publication in the Federal Register (FR). While we have taken steps to ensure the accuracy of this Internet version of the rule, it is not the 

official version of the rule for purposes of compliance. Please refer to the official version in a forthcoming FR publication, which will appear 

on the Government Printing Office’s FDsys website (http://fdsys.gpo.gov/fdsys/search/home.action) and on Regulations.gov 

(http://www.regulations.gov) in Docket No. EPA-R09-OAR-2013-0686. 

6560-50-P 

ENVIRONMENTAL PROTECTION AGENCY 

40 CFR Parts 52 and 81 

[EPA-R09-OAR-2013-0686; FRL-] 

Approval and Promulgation of Implementation Plans and 

Designation of Areas for Air Quality Planning Purposes; State of 

Arizona; Redesignation of the Phoenix-Mesa Nonattainment Area to 

Attainment for the 1997 8-Hour Ozone Standard 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Proposed Rule. 

SUMMARY: Under the Clean Air Act, the Environmental Protection 

Agency (EPA) is proposing to approve, as a revision of the 

Arizona State Implementation Plan, the State’s plan for 

maintaining the 1997 National Ambient Air Quality Standard for 

ozone averaged over eight hours (8-hour ozone standard) in the 

Phoenix-Mesa nonattainment area for ten years beyond 

redesignation, and the related motor vehicle emission budgets, 

because they meet the applicable requirements for such plans and 

budgets. EPA is also proposing to approve a request from the 

Arizona Department of Environmental Quality to redesignate the 

Phoenix-Mesa nonattainment area to attainment of the 1997 8-hour 

ozone standard because the request meets the statutory 

requirements for redesignation under the Clean Air Act. 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9, on 3/14/2014. We have taken 

steps to ensure the accuracy of this version, but it is not the official version. 

2 

DATES: Comments must be received on or before [insert date 30 

days from publication in the Federal Register]. 

ADDRESSES: Submit your comments, identified by Docket ID number 

EPA-R09-OAR-2013-0686, by one of the following methods: 

1. http://www.regulations.gov: Follow the on-line instructions 

for submitting comments. 

2. Email: vagenas.ginger@epa.gov

3. Postal Mail or Delivery: Ginger Vagenas (AIR-2), U.S. 

Environmental Protection Agency, Region 9, 75 Hawthorne 

Street, San Francisco, CA 94105-3901. Deliveries are only 

accepted during the Regional Office’s normal hours of 

operation. 

Instructions: All comments will be included in the public 

docket without change and may be made available online at 

http://www.regulations.gov, including any personal information 

provided, unless the comment includes Confidential Business 

Information (CBI) or other information whose disclosure is 

restricted by statute. Information that you consider CBI or 

otherwise protected should be clearly identified as such and 

should not be submitted through http://www.regulations.gov or 

email. The online docket system at http://www.regulations.gov is 

an anonymous access system, and EPA will not know your identity 

or contact information unless you provide it in the body of your 

comment. If EPA cannot read your comment due to technical 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9, on 3/14/2014. We have taken 

steps to ensure the accuracy of this version, but it is not the official version. 

3 

difficulties and cannot contact you for clarification, EPA may 

not be able to consider your comment. 

Docket: Generally, documents in the docket for this action 

are available electronically at http://www.regulations.gov and 

in hard copy at the EPA Region 9 office. While all documents in 

the docket are listed at http://www.regulations.gov, some 

information may not be specifically listed in the index to the 

docket or may be publicly available only in hard copy at the EPA 

Region 9 office (e.g., copyrighted material, large maps, multivolume reports, or otherwise voluminous materials), and some may 

not be publicly available in electronic or hard copy form (e.g., 

confidential business information). To view the hard copy 

materials, please schedule an appointment during normal business 

hours with the contact person listed in the FOR FURTHER 

INFORMATION CONTACT section. 

FOR FURTHER INFORMATION CONTACT: Ginger Vagenas, U.S. EPA, 

Region 9, 75 Hawthorne Street (AIR-2), San Francisco, CA 94105-

3901. Ginger Vagenas can also be reached at (415) 972-3964, or 

via electronic mail at vagenas.ginger@epa.gov. 

SUPPLEMENTARY INFORMATION: Throughout this document, “we”, “us”, 

and “our” refer to the United States Environmental Protection 

Agency (EPA). 

Table of Contents 

I. Summary of Today’s Proposed Action 
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steps to ensure the accuracy of this version, but it is not the official version. 

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II. Background 

III. Procedural Requirements for Adoption and Submittal of SIP 

Revisions 

IV. Substantive Requirements for Redesignation 

V. Evaluation of the State’s Redesignation Request for the 

Phoenix-Mesa Ozone Nonattainment Area 

A. Determination that the Area Has Attained the 

Applicable NAAQS 

B. The Area Must Have a Fully Approved SIP Meeting 

Requirements Applicable for Purposes of Redesignation 

Under Section 110 and Part D 

1. Basic SIP Requirements Under CAA Section 110 

2. Part D Requirements 

a. Introduction 

b. Permits for New and Modified Major Sources 

c. Conformity Requirements 

C. The Area Must Show the Improvement in Air Quality is 

Due to Permanent and Enforceable Emission Reductions 

D. The Area Must Have a Fully Approved Maintenance Plan 

Under CAA Section 175A 

1. Attainment Inventories and Projected Future 

Inventories 

2. Maintenance Demonstration 

3. Monitoring Network 
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4. Verification of Continued Attainment 

5. Contingency Provisions 

6. Subsequent Maintenance Plan Revisions 

7. Motor Vehicle Emission Budgets 

VI. Proposed Action and Request for Public Comment 

VII. Statutory and Executive Order Reviews 

I. Summary of Today’s Proposed Action

EPA is proposing to take several related actions. First, 

under section 110(k)(3) of the Clean Air Act (CAA or “Act”), EPA 

is proposing to approve, as a revision to the Arizona State 

Implementation Plan (SIP), a plan developed by the Maricopa 

Association of Governments (MAG),1 entitled MAG Eight-Hour Ozone 

Redesignation Request and Maintenance Plan for the Maricopa 

Nonattainment Area, dated February 2009 (“Eight-Hour Ozone 

Maintenance Plan”), and submitted by the Arizona Department of 

Environmental Quality (ADEQ) to EPA on March 23, 2009.2

In connection with the Eight-Hour Ozone Maintenance Plan, 

EPA is proposing to find that the maintenance demonstration 

 

1

 The MAG membership currently consists of the 27 incorporated cities and 

towns within Maricopa County and the contiguous urbanized area, the Gila 

River Indian Community, the Salt River Pima Maricopa Indian Community, Fort 

McDowell Yavapai Nation, Maricopa and Pinal Counties. Representatives of the 

Arizona Department of Transportation (ADOT) and the Citizens Transportation 

Oversight Committee (CTOC) also serve on the Regional Council for 

transportation-related issues.

2 See letter from Patrick J. Cunningham, Acting Director, Arizona Department 

of Environmental Quality, to Laura Yoshii, Acting Regional Administrator, EPA 

Region IX, March 23, 2009. This letter included three enclosures, one of 

which is the Eight-Hour Ozone Maintenance Plan, including appendices A and B 

organized into volumes 1, 2, and 3. 
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steps to ensure the accuracy of this version, but it is not the official version. 

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shows that the Phoenix-Mesa area will continue to attain the 

1997 8-hour ozone National Ambient Air Quality Standard (NAAQS 

or “standard”) for 10 years beyond redesignation and that the 

contingency provisions, which include already implemented 

measures as well as a process for identifying new or more 

stringent measures in the event of a future monitored violation, 

meet all applicable requirements for maintenance plans and the 

related contingency provisions of CAA section 175A. EPA is also 

proposing to approve motor vehicle emission budgets in the 

Eight-Hour Ozone Maintenance Plan because we find they meet the 

applicable transportation conformity requirements under 40 CFR 

93.118(e). 

Second, under CAA section 107(d)(3)(D), EPA is proposing to 

approve ADEQ’s request to redesignate the Phoenix-Mesa 8-hour 

ozone nonattainment area to attainment for the 1997 8-hour ozone 

NAAQS. We are doing so based on our conclusion that the area has 

met the five criteria for redesignation under CAA section 

107(d)(3)(E). This conclusion is based on our proposed 

determination that: the area has attained the 1997 8-hour ozone 

NAAQS; relevant portions of the Arizona SIP are fully approved; 

improvement in air quality in the area is due to permanent and 

enforceable reductions in emissions; Arizona has met all 

requirements applicable to the Phoenix-Mesa 1997 8-hour ozone 

nonattainment area with respect to section 110 and part D of the 
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steps to ensure the accuracy of this version, but it is not the official version. 

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CAA; and, as part of this action, our proposed approval of the 

Eight-Hour Ozone Maintenance Plan. 

II. Background

Ground-level ozone is an oxidant that is formed from 

photochemical reactions in the atmosphere between volatile 

organic compounds (VOC) and oxides of nitrogen (NOX) in the 

presence of sunlight. These two pollutants, referred to as ozone 

precursors, are emitted by many types of pollution sources 

including on-road motor vehicles (cars, trucks, and buses), 

nonroad vehicles and engines, power plants and industrial 

facilities, and smaller area sources such as lawn and garden 

equipment and paints. 

In 1971, under section 109 of the Act, as amended in 1970, 

EPA promulgated the original NAAQS for pervasive air pollutants, 

including photochemical oxidants.3 The NAAQS are concentration 

levels that, the attainment and maintenance of which, EPA has 

determined to be requisite to protect public health (i.e., the 

“primary” NAAQS) and welfare (i.e., the “secondary” NAAQS). In 

1979, EPA revised the chemical designation of the NAAQS from 

“photochemical oxidants” to “ozone,” and established a 1-hour 

ozone NAAQS of 0.12 parts per million (ppm).4 

In March of 1978, Maricopa County was designated as a 1-

hour oxidant nonattainment area (43 FR 8962). In 1979, EPA 

 

3 See 36 FR 8186 (April 30, 1971). 

4 See 44 FR 8202 (February 8, 1979). 
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revised Maricopa County’s designation to refer to ozone (rather 

than oxidant) and reduced the geographic extent of the 

nonattainment area to reflect MAG’s Urban Planning Area 

(“Phoenix metropolitan area”) rather than the entire county. See 

44 FR 16388 (March 19, 1979). Under the CAA, states with 

nonattainment areas are required to submit revisions to their 

SIPs that include a control strategy necessary to demonstrate 

how the area will attain the NAAQS, and EPA took action on a 

number of related SIP revisions submitted by Arizona in the late 

1970s and 1980s for the Phoenix metropolitan 1-hour ozone 

nonattainment area. However, by 1990, the area still had not 

attained the standard, and under the CAA Amendments of 1990, the 

Phoenix metropolitan area was classified as a “moderate” 

nonattainment area with an attainment deadline of November 15, 

1996 (56 FR 56694, November 6, 1991). The area was later 

reclassified as a “serious” nonattainment area with a deadline 

of November 15, 1999 (62 FR 60001, November 6, 1997). 

In 1997, EPA revised the NAAQS for ozone, setting it at 

0.08 ppm averaged over an 8-hour timeframe (referred to herein 

as the “1997 8-hour ozone standard”) to replace the existing 1-

hour ozone standard of 0.12 ppm.5,6 In 2004, EPA designated the 

 

5 See 62 FR 33856 (July 18, 1997). 

6 On March 27, 2008 (73 FR 16436), EPA lowered the 8-hour ozone standard to 

0.075 ppm (the 2008 8-hour ozone standard), and on May 21, 2012, EPA 

designated the Phoenix-Mesa area as marginal nonattainment for the 2008 8-

hour ozone standard (77 FR 30088). Today’s proposed action relates to a 
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steps to ensure the accuracy of this version, but it is not the official version. 

9 

Phoenix-Mesa area as nonattainment for the 1997 8-hour ozone 

standard and established June 15, 2005 as the date when the 1-

hour ozone standard would be revoked. The Phoenix-Mesa 8-hour 

ozone nonattainment area covers a much larger portion of 

Maricopa County than the Phoenix metropolitan 1-hour ozone area 

and also includes the Apache Junction portion of Pinal County.7

Just prior to revocation of the 1-hour ozone standard, EPA 

redesignated the Phoenix metropolitan 1-hour ozone nonattainment 

area to attainment (70 FR 34362, June 14, 2005).8

On April 15, 2004, EPA designated Phoenix-Mesa as Subpart 1 

nonattainment for the 1997 8-hour ozone standard under CAA 

section 172 with an attainment deadline no later than June 15, 

2009.9 The designation became effective on June 15, 2004. The 

Phoenix-Mesa nonattainment area is located in the central 

portion of Arizona and encompasses 4,880 square miles, including 

the urban portions of Maricopa and Pinal Counties, and areas of 

Indian country of the Fort McDowell Yavapai Nation, the Salt 

River-Pima Maricopa Indian Community, and the Tohono O’odham 

Nation. For a precise description of the geographic boundaries 

 

maintenance plan and redesignation request for the 1997 8-hour ozone 

standard, not the more stringent 2008 8-hour ozone standard. 

7 The precise boundaries of the Phoenix-Mesa 8-hour ozone nonattainment area 

and the Phoenix metropolitan 1-hour ozone nonattainment are found in 40 CFR 

81.303. 

8 A more detailed description of the history of 1-hour ozone planning in the 

Phoenix metropolitan area is presented in section II of EPA’s proposed 

redesignation for the 1-hour ozone standard. See 70 FR 13425 at 13426-13428 

(March 21, 2005). 

9 See 69 FR 23858 (April 30, 2004) and 40 CFR 81.303. 
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steps to ensure the accuracy of this version, but it is not the official version. 

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of the Phoenix-Mesa nonattainment area, see 40 CFR 81.303 and 

figure 1-1 of the Eight-Hour Ozone Maintenance Plan. MAG is the 

agency with primary responsibility for developing air quality 

plans related to the 1997 8-hour ozone NAAQS for the PhoenixMesa nonattainment area. 

Under part D, subpart 1 of the Act, states must submit 

plans to come into attainment within 3 years of the effective 

date of the nonattainment designation and must attain the 

standard as expeditiously as practicable, but no later than 5 

years after the effective date of the designation. Later, in the 

wake of a court decision partially vacating EPA’s regulations 

implementing the 1997 8-hour ozone standard,10 EPA classified the 

Phoenix-Mesa ozone nonattainment area as “marginal” under 

subpart 2 of part D of title I of the CAA.11

On June 13, 2007, ADEQ submitted a SIP revision 

demonstrating attainment of the 1997 8-hour ozone standard in 

the Phoenix-Mesa nonattainment area by the attainment date of 

June 15, 2009 (“Eight-Hour Ozone Attainment Plan”). In June 

2012, EPA approved the Eight-Hour Ozone Attainment Plan.12 On 

March 23, 2009, ADEQ submitted the Eight-Hour Ozone Maintenance 

Plan as a revision to the Arizona SIP. 

 

10 See South Coast Air Quality Management Dist. v. EPA, 472 F3d 882 (D.C. 

Cir. 2006). 

11 See 77 FR 28424 (May 14, 2012). June 13, 2012 is the effective date for 

the “marginal” classification of the Phoenix-Mesa 8-hour ozone nonattainment 

for the 1997 8-hour ozone NAAQS. 

12 See 77 FR 21690 (April 11, 2012) and 77 FR 35285 (June 13, 2012).
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steps to ensure the accuracy of this version, but it is not the official version. 

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In summary, the Phoenix metropolitan area was originally 

designated as nonattainment for the photochemical oxidant, later 

1-hour ozone NAAQS, but was later redesignated as attainment for 

the 1-hour ozone NAAQS prior to the revocation of that standard. 

With respect to the 1997 8-hour ozone NAAQS, EPA designated a 

larger geographic area, the Phoenix-Mesa area, as nonattainment, 

later classified as “marginal,” for the 1997 8-hour ozone NAAQS. 

ADEQ’s request to redesignate the Phoenix Mesa area as 

attainment for the 1997 8-hour ozone NAAQS is the subject of 

today’s proposed action. Lastly, EPA has also designated the 

Phoenix Mesa area as “marginal” nonattainment for the 2008 ozone 

NAAQS. Today’s proposed action does not affect the designation 

of the Phoenix-Mesa area for the 2008 ozone NAAQS. 

III. Procedural Requirements for Adoption and Submittal of SIP 

Revisions 

Section 110(l) of the Act requires States to provide 

reasonable notice and public hearing prior to adoption of SIP 

revisions. Appendix B, Exhibit 1 of the Eight-Hour Ozone 

Maintenance Plan documents the public review process followed by 

MAG in adopting the plan prior to transmittal to ADEQ for 

subsequent submittal to EPA as a revision to the Arizona SIP. 

The documentation in Exhibit 1 also provides evidence that 

reasonable notice of a public hearing was provided to the public 

and that a public hearing was conducted prior to adoption. 
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steps to ensure the accuracy of this version, but it is not the official version. 

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Specifically, notice of the availability of, and opening of 

a 30-day comment period on, the public-draft Eight-Hour Ozone 

Maintenance Plan was published on December 23, 2008, in a 

newspaper of general circulation within the Phoenix area. The 

public hearing was held on January 22, 2009. One individual 

commented on the draft maintenance plan during the public 

hearing. No written comments were received during the public 

comment period. MAG provided responses to comments in Exhibit 1 

of Appendix B. 

On February 25, 2009, the MAG Regional Council adopted the 

Eight-Hour Ozone Maintenance Plan, as certified in Appendix B, 

exhibit 2 of the plan. Following adoption, MAG provided the 

maintenance plan to ADEQ, and ADEQ adopted the plan and 

submitted it to EPA for approval on March 23, 2009. 

Based on the documentation provided in Appendix B, we find 

that the submittal of the Eight-Hour Ozone Maintenance Plan as a 

SIP revision satisfies the procedural requirements of section 

110(l) of the Act. 

IV. Substantive Requirements for Redesignation 

The CAA establishes the requirements for redesignation of a 

nonattainment area to attainment. Specifically, section 

107(d)(3)(E) allows for redesignation provided that the 

following criteria are met: (1) EPA determines that the area has 

attained the applicable NAAQS; (2) EPA has fully approved the 
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steps to ensure the accuracy of this version, but it is not the official version. 

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applicable implementation plan for the area under 110(k); (3) 

EPA determines that the improvement in air quality is due to 

permanent and enforceable reductions; (4) EPA has fully approved 

a maintenance plan for the area as meeting the requirements of 

CAA 175A; and (5) the State containing such area has met all 

requirements applicable to the area under section 110 and part D 

of the CAA. Section 110 identifies a comprehensive list of 

elements that SIPs must include, and part D establishes the SIP 

requirements for nonattainment areas. Part D is divided into six 

subparts. The generally-applicable nonattainment SIP 

requirements are found in part D, subpart 1, and the ozonespecific SIP requirements are found in part D, subpart 2. 

EPA provided guidance on redesignations in a document 

entitled “State Implementation Plans; General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 

1990”, published in the Federal Register on April 16, 1992 (57 

FR 13498), and supplemented on April 28, 1992 (57 FR 18070) 

(referred to herein as the “General Preamble”). Additional 

guidance was issued in a September 4, 1992 memorandum from John 

Calcagni, Director, Air Quality Management Division, EPA Office 

of Air Quality Planning and Standards, entitled “Procedures for 

Processing Requests to Redesignate Areas to Attainment” 

(referred to herein as the “Calcagni memo”). Maintenance plan 

submittals are SIP revisions, and as such, EPA is obligated, 
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steps to ensure the accuracy of this version, but it is not the official version. 

14 

under CAA section 110(k), to approve them or disapprove them 

depending upon whether they meet the applicable CAA requirements 

for such plans. 

For reasons set forth below in section V of this document, 

we propose to approve ADEQ’s request for redesignation of the 

Phoenix-Mesa ozone nonattainment area to attainment for the 1997 

8-hour ozone NAAQS based on our conclusion that all the criteria 

under CAA section 107(d)(3)(E) have been satisfied. 

V. Evaluation of the State’s Redesignation Request for the 

Phoenix-Mesa Ozone Nonattainment Area 

A. Determination That the Area Has Attained the Applicable NAAQS

CAA section 107(d)(3)(E)(i) requires that we determine that 

the area has attained the NAAQS. EPA generally makes the 

determination of whether an area’s air quality meets the ozone 

NAAQS based upon the most recent three years of complete, 

quality-assured data gathered at established State and Local Air 

Monitoring Stations (SLAMS) in the nonattainment area and 

entered into the EPA Air Quality System (AQS) database. Data 

from air monitors operated by state or local agencies in 

compliance with EPA monitoring requirements must be submitted to 

AQS. Heads of monitoring agencies annually certify that these 

data are accurate to the best of their knowledge. Accordingly, 

EPA relies primarily on data in AQS when determining the 
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steps to ensure the accuracy of this version, but it is not the official version. 

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attainment status of areas.13 All data are reviewed to determine 

the area’s air quality status in accordance with 40 CFR part 50, 

Appendix I. 

Under EPA regulations at 40 CFR part 50, the 1997 ozone 

standard is met at an ambient air quality monitoring site when 

the 3-year average of the annual fourth-highest daily maximum 8-

hour average ozone concentration is less than or equal to 0.08 

ppm.14 This 3-year average is referred to as the design value. 

When the design value is less than or equal to 0.084 ppm (based 

on the rounding convention in 40 CFR part 50, Appendix I) at 

each monitoring site within the area, the area is meeting the 

NAAQS. The data completeness requirement is met with the 3-year 

average percent of days with valid ambient monitoring data is at 

least 90 percent of the days during the designated ozone 

monitoring season, and no single year has less than 75 percent 

data completeness as determined in Appendix I of 40 CFR part 50. 

Three state or local agencies are responsible for 

monitoring ambient air quality data in the Phoenix-Mesa 

nonattainment area: the Maricopa County Air Quality Department 

(MCAQD), the Pinal County Air Quality Control District (PCAQCD), 

and ADEQ. These agencies submit monitoring network plan reports 

to EPA on an annual basis. These reports discuss the status of 

 

13 See 40 CFR 50.10; 40 CFR part 50, Appendix I; 40 CFR part 53; 40 CFR part 

58, Appendices A, C, D, and E. 

14 See 40 CFR 50.10 and 40 CFR part 50, Appendix I. 
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steps to ensure the accuracy of this version, but it is not the official version. 

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the air monitoring network, as required under 40 CFR part 58. 

Beginning in 2007, EPA has reviewed these annual plans for 

compliance with the applicable reporting requirements in 40 CFR 

58.10. With respect to ozone, we have found that MCAQD’s, 

PCAQCD’s, and ADEQ’s annual network plans meet the applicable 

reporting requirements under 40 CFR part 58.15 

EPA conducts periodic technical system audits of the state 

and local ambient air monitoring networks, and has done so for 

ADEQ, MCAQD, and PCAQCD. For the purposes of this action, EPA 

has reviewed the findings in EPA’s technical system audits of 

the networks operated by the three relevant agencies and notes 

that none of the findings in these reports cast doubt on the 

reliability of the ozone data collected at the various 

monitoring sites in these networks.16

During the relevant time period, the ozone monitoring 

network in the Phoenix-Mesa nonattainment area comprised 20 

ozone monitors: MCAQD operated 18 monitors17, ADEQ operated one 

monitor, and PCAQCD operated one monitor. Please see figure 2-1 

 

15 See EPA letters to MCAQCD, PCAQCD, and ADEQ concerning annual network plan 

reports, which are included in the docket for this rulemaking. 

16 For the most recent technical system audits (TSAs), see EPA’s report on the 

Agency’s September 2008 audit of MCAQCD’s network, EPA’s final TSA report for 

ADEQ’s network dated January 2013, and EPA’s final TSA report for PCAQCD’s 

network dated June 2013, which are included in the docket for this 

rulemaking. 

17 The Mesa ozone monitor, operated by MCAQD, began operation on November 1, 

2012 and therefore only gathered data for two months during the 2010-2012 

design value period. As a result, this monitor is not appropriate to consider 

in determining whether the area has attained the 1997 ozone standard. In the 

future, as complete data become available, the monitor will be eligible for 

use in determining continued attainment. 
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steps to ensure the accuracy of this version, but it is not the official version. 

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in the Eight-Hour Ozone Maintenance Plan for a map showing the 

locations of the monitors constituting the State and local 

agency regional ozone monitoring network. Based on population 

and ambient ozone, EPA regulations required only three ozone 

monitoring sites in the Phoenix-Mesa-Glendale Metropolitan 

Statistical Area (MSA) during the 2010-2012 period. Thus, the 

ozone monitoring network in the Phoenix-Mesa nonattainment area 

exceeds the requirements for the minimum number of monitoring 

sites designated as SLAMS for that pollutant. 

MCAQD, PCAQCD, and ADEQ annually certify that the data they 

submit to AQS are complete and quality-assured.18 All 20 sites 

monitored ozone concentrations on a continuous basis using 

Federal Equivalent Method (FEM) analyzers. The spatial scale and 

site type (monitoring objective type) of most of the ozone 

monitoring sites in the nonattainment area are “neighborhood” 

and “population exposure,” respectively. The Blue Point, Cave 

Creek, Pinnacle Peak, and Rio Verde sites are classified as 

“urban” scale with site types of “maximum ozone concentrations,” 

while the Humboldt Mountain site is classified as “regional 

scale” with a site type of “maximum ozone concentrations.” The 

Fountain Hills and JLG Supersite sites are also sited to measure 

 

18 For the most recent data certification submittals, see MCAQCD, PCAQCD, and 

ADEQ letters concerning data certification for 2010, 2011, and 2012, which 

are included in the docket for this rulemaking. 
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steps to ensure the accuracy of this version, but it is not the official version. 

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“maximum ozone concentrations” but are located at the 

“neighborhood” scale.19 

In addition to the SLAMS ozone network maintained by MCAQD, 

PCAQCD, and ADEQ, there are five tribal monitors located within 

the nonattainment area. The Salt River Pima-Maricopa Indian 

Community (Salt River) operates four ozone monitors and the Fort 

McDowell Yavapai Nation (Fort McDowell) operates one monitor on 

tribal lands located in the eastern portion of the nonattainment 

area. The ozone monitoring data from Fort McDowell is 

characterized as “informational” and therefore not suitable for 

comparison against the 1997 ozone standard. Conversely, the Salt 

River ozone monitors have the basic monitoring objective of 

“NAAQS comparison” and the data should be considered 

“regulatory” and appropriate for use when determining if the 

nonattainment area is attaining the 1997 ozone standard. 

Consistent with the requirements contained in 40 CFR part 

50, EPA has reviewed the ozone ambient air monitoring data as 

recorded in AQS for the monitoring period from 2010 through 2012 

collected at the monitoring sites discussed above and found that 

the data meet our completeness criteria (see table 1). 

Table 1: Summary of Ambient Data for Ozone Collected Within 

Phoenix-Mesa Ozone Nonattainment Area, 2010-2012 

 

19 The sources of information for this paragraph include ADEQ’s “State of 

Arizona Air Monitoring Network Plan for the Year 2013,” dated October 29, 

2013; MCAQD’s “2012 Air Monitoring Network Review,” undated; and PCAQCD’s 

“2013 Ambient Monitoring Network Plan and 2012 Data Summary,” dated July 1, 

2013. 
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Site Site ID Agency Parameter 2010-2012 Design 

Value (DV) and % 

Complete 

Apache Junction 04-013-3001 PCAQCD DV (ppm) 0.074 

% complete 98 

Blue Point 04-013-9702 MCAQD DV (ppm) 0.075 

% complete 99 

Buckeye 04-013-4011 MCAQD DV (ppm) 0.066 

% complete 100 

Cave Creek 04-013-4008 MCAQD DV (ppm) 0.077 

% complete 100 

Central Phoenix 04-013-3002 MCAQD DV (ppm) 0.074 

% complete 100 

Dysart 04-013-4010 MCAQD DV (ppm) 0.071 

% complete 100 

Falcon Field 04-013-1010 MCAQD DV (ppm) 0.069 

% complete 99 

Fountain Hills 04-013-9704 MCAQD DV (ppm) 0.076 

% complete 99 

Glendale 04-013-2001 MCAQD DV (ppm) 0.076 

% complete 100 

High School 04-013-7024 SRPMIC DV (ppm) 0.074 

% complete 99 

Humboldt Mountain 04-013-9508 MCAQD DV (ppm) 0.075 

% complete 100 

JLG Supersite 04-013-9997 ADEQ DV (ppm) 0.076 

% complete 98 

Lehi 04-013-7022 SRPMIC DV (ppm) 0.073 

% complete 98 

North Phoenix 04-013-1004 MCAQD DV (ppm) 0.081 
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% complete 100 

Pinnacle Peak 04-013-2005 MCAQD DV (ppm) 0.077 

% complete 7820

Red Mountain 04-013-7021 SRPMIC DV (ppm) 0.077 

% complete 93 

Rio Verde 04-013-9706 MCAQD DV (ppm) 0.074 

% complete 98 

Senior Center 04-013-7020 SRPMIC DV (ppm) 0.074 

% complete 95 

South Phoenix 04-013-4003 MCAQD DV (ppm) 0.076 

% complete 98 

South Scottsdale 04-013-3003 MCAQD DV (ppm) 0.077 

% complete 100 

Tempe 04-013-4005 MCAQD DV (ppm) 0.070 

% complete 99 

West Chandler 04-013-4004 MCAQD DV (ppm) 0.074 

% complete 100 

West Phoenix 04-013-0019 MCAQD DV (ppm) 0.078 

% complete 100 

Table 1 summarizes the site-specific 3-year ozone design 

values for all monitoring sites within the Phoenix-Mesa 

nonattainment area for the period of 2010-2012. As shown in 

table 1, the design value for the 2010-2012 period was less than 

0.084 ppm at all of the monitors in the Phoenix-Mesa ozone 

nonattainment area. Therefore, we are proposing to determine, 

 

20 The Pinnacle Peak site was temporarily shut down on November 16, 2011 and 

relocated to a nearby location on July 1, 2012. See Letter from Ben Davis, 

Air Monitoring Manager, MCAQD, to Michael Flagg, Air Quality Analysis Office, 

EPA Region 9, dated January 31, 2012. 
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21 

based on complete quality-assured data for the 2010-2012 period, 

that the Phoenix-Mesa ozone nonattainment area has attained the 

1997 8-hour ozone standard. Preliminary data for 2013 are also 

consistent with continued attainment.21 Given the timing of this 

proposed action after the end of 2013 but before the monitoring 

agencies must enter data collected during the final quarter of 

the 2013 into AQS, we will be updating this determination based 

on design values calculated for 2011-2013, and preliminary 

review of available 2014 data, for the purposes of the final 

action. 

B. The Area Must Have a Fully Approved SIP Meeting the 

Requirements Applicable for Purposes of Redesignation Under 

Section 110 and Part D 

Section 107(d)(3)(E)(ii) and (v) require EPA to determine 

that the area has a fully approved applicable SIP under section 

110(k) that meets all applicable requirements under section 110 

and part D for the purposes of redesignation. 

1. Basic SIP Requirements Under CAA Section 110 

Section 110(a)(2) sets forth the general elements that a 

SIP must contain in order to be fully approved. EPA has analyzed 

the Arizona SIP and determined that it is consistent with the 

requirements of section 110(a)(2). The Phoenix-Mesa portion of 

the approved Arizona SIP, which includes rules pertaining to 

 

21 See the AQS Preliminary Design Value Report for 2013 dated March 6, 2014, 

included in the docket for this rulemaking. 
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areas and sources under the jurisdiction of ADEQ, MCAQD, and 

PCAQCD, contains enforceable emission limitations; requires 

monitoring, compiling, and analyzing of ambient air quality 

data; requires preconstruction review of new or modified 

stationary sources; provides adequate funding, staff, and 

associated resources necessary to implement its requirements; 

and provides the necessary assurances that the State of Arizona 

maintains responsibility for ensuring adequate implementation of 

the SIP where the State is relying on local or regional 

governments or agencies for implementation of the SIP.22

 

22 We note that SIPs must be fully approved only with respect to the 

applicable requirements for purposes of redesignation in accordance with 

section 107(d)(3)(E)(ii). Thus, for example, CAA section 110(a)(2)(D) 

requires that SIPs contain certain measures to prevent sources in a state 

from significantly contributing to air quality problems in another state 

(transport SIP). However, the section 110(a)(2)(D) requirements for a state 

are not linked with a particular nonattainment area’s designation and 

classification in that state. EPA believes that the requirements linked with 

a particular nonattainment area’s designation and classification are the 

relevant measures to evaluate in reviewing a redesignation request. The 

transport SIP requirements, where applicable, continue to apply to a state 

regardless of the designation of any one particular area in the state. Thus, 

we do not believe that these requirements should be construed to be 

applicable requirements for the purposes of redesignation. In addition, EPA 

believes that the other section 110 elements that are not connected with 

nonattainment plan submissions and not linked with an area’s attainment 

status are not applicable requirements for the purposes of redesignation. The 

State will still be subject to these requirements after the Phoenix-Mesa 

nonattainment area is redesignated. 

This policy is consistent with EPA’s existing policy on applicability 

of conformity (i.e., for redesignations) and oxygenated fuels requirements. 

See Reading, Pennsylvania, proposed and final rulemakings (61 FR 53174 dated 

October 10, 1996 and 62 FR 24816 dated May 7, 1997); Cleveland-Akron-Lorain, 

Ohio, final rulemaking (61 FR 20458 dated May 7, 1996); and Tampa, Florida, 

final rulemaking (60 FR 62748 dated December 7, 1995). See also the 

discussion of this issue in the Cincinnati redesignation (65 FR 37879 at 

37890 dated June 19, 2000), in the Pittsburgh redesignation (66 FR 53094 

dated October 19, 2001), and in the South Coast redesignation (72 FR 6986 

dated February 14, 2007 and 72 FR 26718 dated May 11, 2007). 
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steps to ensure the accuracy of this version, but it is not the official version. 

23 

On numerous occasions, we have approved Arizona submittals 

addressing the basic CAA section 110 provisions. There are no 

outstanding or disapproved applicable SIP submittals with 

respect to the Phoenix-Mesa portion of the SIP that prevent 

redesignation of the Phoenix-Mesa nonattainment area for the 

1997 8-hour ozone standard.23 Therefore, we propose to find that 

Arizona has met all SIP requirements for the Phoenix-Mesa ozone 

area applicable for the purposes of redesignation under section 

110 of the CAA (General SIP Requirements). 

2. Part D Requirements 

a. Introduction 

The CAA contains two sets of provisions, subparts 1 and 2, 

that address planning and emission control requirements for 

ozone nonattainment areas. Both of these subparts are found in 

title I, part D of the CAA; sections 171-179 and sections 181-

185, respectively. Subpart 1 contains general, less prescriptive 

requirements for all nonattainment areas of any pollutant, 

including ozone, governed by a NAAQS. Subpart 2 contains 

additional, more specific requirements for ozone nonattainment 

areas classified under subpart 2. 

 

23 On November 5, 2012 (77 FR 66398) EPA issued a partial approval and 

partial disapproval of Arizona’s “infrastructure” SIP for the 1997 8-hour 

ozone NAAQS. While this final rule was not a full approval, it does not 

represent an obstacle to redesignation of the Phoenix-Mesa 1997 ozone 

nonattainment area because the infrastructure elements effective in the 

Phoenix-Mesa area that EPA disapproved (i.e., certain PSD program elements, 

composition of air quality hearing boards) are not related to the 

nonattainment SIP requirements for the Phoenix-Mesa ozone nonattainment area 

and thus are not relevant for the purposes of redesignation. 
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steps to ensure the accuracy of this version, but it is not the official version. 

24 

The applicable subpart 1 requirements are contained in 

sections 172(c)(1)-(9) and 176 of the CAA. Under subpart 1, with 

respect to the Phoenix-Mesa 8-hour ozone nonattainment area, the 

state of Arizona is required to submit SIP revisions that 

provide for: 

· Implementation of all reasonably available control measures 

(RACM), including, at a minimum, reasonable available 

control technology for existing sources and attainment of 

the standard (section 172(c)(1)); 

· Reasonable further progress (RFP) (section 172(c)(2)); 

· A comprehensive, accurate, current inventory of actual 

emissions from all sources of the relevant pollutant or 

pollutants in the area (section 172(c)(3)); 

· Identification and quantification of the emissions, if 

any, of any such pollutant which will be allowed in 

accordance with section 173(a)(1)(B) (i.e., new or modified 

stationary sources located in established economic 

development zones) (section 172(c)(4)); 

· Permits for the construction of new and modified major 

stationary sources in the nonattainment area (section 

172(c)(5))(herein, referred to as “nonattainment NSR” or 

“NSR”); 
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· Enforceable emission limitations as may be necessary or 

appropriate to provide for attainment of such standard in 

such area by the applicable attainment date (section 

172(c)(6)); 

· Compliance with section 110(a)(2) of the Act (section 

172(c)(7)); 

· Use of equivalent modeling emission inventory, and planning 

procedures if approved by EPA (section 172(c)(8)); 

· Contingency measures (section 172(c)(9)); and 

· Interagency consultation and enforceability for the 

purposes of transportation conformity (section 176(c)(4) 

and 40 CFR 51.390). 

On June 13, 2012 (77 FR 35285), EPA approved the Eight-Hour 

Ozone Attainment Plan for the Phoenix-Mesa nonattainment area 

based on the determination that it met all applicable 

requirements for such plans under subpart 1 of part D, title 1 

of the CAA for the 1997 8-hour ozone NAAQS. Specifically, we 

approved the following SIP elements: 

· The RACM demonstration and attainment demonstration as 

meeting the requirements of section 172(c)(1), 40 CFR 

51.912(d), and 40 CFR 51.908; 

· The RFP demonstration as meeting the requirements of CAA 

section 172(c)(2) and 40 CFR 51.910; 
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· The 2002 base year emission inventory as meeting the 

requirements of section 172(c)(3) and 40 CFR 51.915; and 

· The contingency measures for failure to make RFP or to 

attain as meeting the requirements of section 172(c)(9). 

In addition, we note that the approved Eight-Hour Ozone 

Attainment Plan relied on enforceable emission limitations 

necessary to attain the 1997 8-hour ozone NAAQS by the 

applicable attainment date in compliance with section 172(c)(6) 

and the plan was adopted and submitted in compliance with 

section 110(a)(2) as required under section 172(c)(7). 

Furthermore, the State of Arizona did not rely on sections 

172(c)(4) (i.e., identification and quantification of certain 

emission increases) or 172(c)(8) (equivalent techniques) in 

connection with the Eight-Hour Ozone Attainment Plan. The 

approved Eight-Hour Ozone Attainment Plan did not address the 

following SIP elements: (1) NSR permit requirements in the 

nonattainment area (section 172(c)(5)) and (2) transportation 

conformity provisions related to interagency consultation and 

enforceability (section 176(c)(4) and 40 CFR 51.390). We address 

these two remaining part D SIP elements later in this 

subsection.24

 

24 The requirements for SIP revisions to demonstrate RACM, RFP, attainment, 

and contingencies (for failure to meet RFP or attainment) in subpart 1 are 

not applicable for the purposes of evaluating a redesignation request. Such 

requirements are directed at ensuring attainment by the applicable attainment 

date, and since, as discussed in section V.A., the area is showing 
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steps to ensure the accuracy of this version, but it is not the official version. 

27 

As noted above, the Phoenix-Mesa nonattainment area was 

initially designated nonattainment under subpart 1 of the CAA, 

but was subsequently classified as marginal nonattainment for 

the 1997 8-hour ozone standard under subpart 2 of the CAA (77 FR 

28424, May 14, 2012). The effective date of the classification 

of the Phoenix-Mesa nonattainment area as marginal was June 13, 

2012, and under our subpart 2 classifications rule, states had 

one year from the effective date of that final rule (i.e., until 

June 13, 2013) to submit SIP revisions. 

ADEQ has not submitted any SIP revisions for the PhoenixMesa nonattainment area in response to the area’s classification 

to marginal.25 However, EPA believes that this does not preclude 

this redesignation from being approved, based on (1) EPA’s 

longstanding policy of evaluating requirements in accordance 

with the requirements due at the time the redesignation request 

is submitted; and (2) consideration of the inequity of 

 

attainment, the requirements have no meaning at this point. See the General 

Preamble, 74 FR 13498, at 13564 (April 16, 1992).

25 In any event, the State of Arizona is not required to submit further SIP 

revisions to satisfy additional requirements under section 182(a)(2)(A) to 

correct RACT rules for the Phoenix-Mesa 8-hour ozone nonattainment area 

because we already determined that the State had met the VOC RACT 

requirements under section 182(a)(2)(A). See our proposed rule (70 FR 13425, 

at 13435, March 21, 2005) and final rule (70 FR 34362, at 34363, June 14, 

2005) redesignating the Phoenix metropolitan area as attainment for the 1-

hour ozone NAAQS. We also note that the State of Arizona previously 

submitted, and EPA approved, an “enhanced” vehicle inspection and maintenance 

(I/M) program that exceeds the requirements of section 182(a)(2)(B) for the 

Phoenix-Mesa nonattainment area, if those requirements were applicable for 

the purposes of redesignation. See 69 FR 2912 (January 22, 2003). Lastly, the 

State of Arizona previously submitted, and EPA approved Maricopa County’s 

emissions statement rule and thereby has complied with section 182(a)(3)(B), 

if that requirement were applicable for the purposes of redesignation for the 

1997 8-hour ozone NAAQS. See 70 FR 7038 (February 10, 2005).
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28 

retroactively applying any requirements that might be applied in 

the future. 

Under EPA’s longstanding interpretation of section 

170(d)(3)(E) of the CAA, to qualify for redesignation, states 

requesting redesignation to attainment must meet only the 

relevant SIP requirements that came due prior to the submittal 

of a complete redesignation request.26 At the time the 

redesignation request was submitted (i.e., March 23, 2009), the 

Phoenix-Mesa nonattainment area was not classified under subpart 

2, and thus, subpart 2 requirements were not yet due for this 

area. 

Moreover, it would be inequitable to retroactively apply 

any new SIP requirements that were not applicable at the time 

the request was submitted. The D.C. Circuit Court has recognized 

the inequity in such retroactive rulemakings. See Sierra Club v. 

Whitman 285 F.3d 63 (D.C. Cir. 2002), in which the court upheld 

a district court’s ruling refusing to make retroactive an EPA 

determination of nonattainment that was past the statutory due 

date. Such a determination would have resulted in the imposition 

of additional requirements on the area. The court stated, 

 

26 See the Calcagni memo; see also Memorandum entitled “State Implementation 

Plan (SIP) Requirements for Areas Submitting Requests for Redesignation to 

Attainment of the Ozone and Carbon Monoxide (CO) National Ambient Air Quality 

Standards (NAAQS) on or after November 15, 1992,” from Michael Shapiro, 

Acting Assistant Administrator for Air and Radiation dated September 17, 

1993; Redesignation of Detroit-Ann Arbor, Michigan, 60 FR 12459 (March 7, 

1995); Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004), upholding this 

interpretation; and Redesignation of St. Louis, Missouri, 68 FR 25418, 25424, 

25427 (May 12, 2003). 
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“[a]lthough EPA failed to make the nonattainment determination 

within the statutory frame, Sierra Club’s proposed solution only 

makes the situation worse. Retroactive relief would likely 

impose large costs on the states, which would face fines and 

suits for not implementing air pollution prevention plans in 

1997, even though they were not on notice at the time.” Id. at 

68. Similarly here, it would be unfair to penalize the PhoenixMesa nonattainment area by applying to it, for purposes of 

redesignation, additional SIP requirements under subpart 2 that 

were not in effect or yet due at the time it submitted its 

redesignation request, or the time that the Phoenix-Mesa 

nonattainment area attained the 1997 ozone NAAQS. 

In the following subsection, we address the following SIP 

elements: (1) NSR permit requirements in the nonattainment area 

(section 172(c)(5)) and (2) transportation conformity provisions 

related to interagency consultation and enforceability (section 

176(c)(4) and 40 CFR 51.390). 

b. Permits for New and Modified Major Sources 

To meet the requirements of CAA section 172(c)(5), states 

must submit SIP revisions that meet the requirements under 40 

CFR 51.165 (“Permit requirements”), and EPA regulations at 40 

CFR 51.914, which extend the SIP requirements of 40 CFR 51.165 

to areas designated as nonattainment for the 1997 8-hour ozone 

standard. 
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Under 40 CFR 51.165, states are required to submit SIP 

revisions that establish certain requirements for new or 

modified stationary sources in nonattainment areas, including 

provisions to ensure that major new sources or major 

modifications of existing sources of nonattainment pollutants 

incorporate the highest level of control, referred to as the 

lowest achievable emission rate (LAER), and that increases in 

emissions from such stationary sources are offset so as to 

provide for reasonable further progress towards attainment. 

The process for reviewing permit applications and issuing 

permits for new or modified stationary sources of air pollution 

is referred to as new source review. With respect to new major 

sources or major modifications at existing major sources of 

nonattainment pollutants in nonattainment areas, this process is 

referred to as nonattainment NSR or simply NSR. With respect to 

new major sources or major modifications at existing major 

sources of pollutants for which as area is designated attainment 

or unclassifiable, states are required to submit SIP revisions 

that ensure that major new stationary sources and major 

modifications of existing stationary sources meet the federal 

requirements for prevention of significant deterioration (PSD), 

including application of the best available control technology 

(BACT) for each applicable pollutant emitted in significant 

amounts, among other requirements. 
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In the Phoenix-Mesa nonattainment area, EPA, MCAQD, PCAQCD, 

and ADEQ share responsibility for issuing permits. EPA has the 

responsibility for permit application review and permit issuance 

for new or modified stationary sources in Indian country of the 

Fort McDowell Yavapai Nation, the Salt River-Pima Maricopa 

Indian Community, and the Tohono O’odham Nation. MCAQD and 

PCAQCD are responsible for permitting for most stationary 

sources located within their respective counties and to portable 

sources that operate solely within the boundaries of the 

counties. ADEQ has jurisdiction over refineries, copper 

smelters, coal-fired power plants, Portland cement plants 

throughout the State and over sources that operate in multiple 

counties or outside the boundaries of Maricopa, Pima, and Pinal 

counties. 

EPA has promulgated nonattainment NSR rules at 40 CFR 

49.166 through 49.175 that establish the necessary permitting 

requirements for new or modified major stationary sources in the 

areas of Indian country located within the Phoenix-Mesa 

nonattainment area. With respect to PCAQCD, the existing Arizona 

SIP does not include rules that meet nonattainment NSR 

requirements for Pinal County; however, because the Pinal County 

portion of the nonattainment area was newly designated as 

nonattainment for ozone in 2004, i.e., had not previously been 

part of the Phoenix metropolitan 1-hour ozone nonattainment 
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32 

area, EPA’s regulations in appendix S to 40 CFR part 51 apply 

until such time as nonattainment NSR rules meeting the 

applicable requirements are approved by EPA as a revision to the 

Arizona SIP. See 40 CFR 52.24(k). 

EPA has not approved nonattainment NSR rules for ADEQ and 

MCAQD since the 1980s, and the existing SIP-approved NSR rules 

do not comply with all of the current SIP NSR requirements under 

the CAA, as amended in 1990, and under 40 CFR 51.165 for ozone 

nonattainment areas. However, the existing SIP-approved NSR 

rules for both ADEQ and MCAQD meet the basic requirements of a 

nonattainment NSR program, including the definition of “major 

stationary source” as any stationary source in a nonattainment 

area with a potential to emit 100 tons per year or more, 

emissions limitations that constitute LAER, and emissions 

reductions to offset emissions increases that would otherwise 

occur. See Arizona Administrative Code (AAC) section R9-3-101 

(“Definitions”) and section R9-3-302 (“Installation permits for 

sources in nonattainment areas”); and Maricopa County Rule 21.0 

(“Procedures for Obtaining an Installation Permit”). Also, 

because the SIP-approved NSR rules apply “in any nonattainment 

area for the pollutant(s) for which the source is classified as 

a major source,” AAC R9-3-302(A), the requirements apply 

throughout the Phoenix-Mesa 1997 8-hour ozone nonattainment 
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33 

area, except for Indian country and for sources subject to Pinal 

County jurisdiction, as discussed above. 

Moreover, ADEQ’s and MCAQD’s SIP-approved NSR rules have 

served as a federally-enforceable constraint on the growth of 

stationary source emissions, and thus have supported the 

region’s efforts to lower ambient ozone concentrations in the 

Phoenix-Mesa area. Those efforts have resulted in attainment of 

the standard since 2007 (see table 2, below) and thus we find 

that ADEQ’s and MCAQD’s SIP-approved NSR rules are likely to 

continue to support continued attainment of the standard during 

the maintenance phase after redesignation. 

Therefore, given that a portion of the nonattainment area 

is subject to federal rules implementing the nonattainment NSR 

requirements (Indian country and the Pinal County portion of the 

nonattainment area) and given that the fundamental nonattainment 

NSR requirements are approved into the SIP for the other 

portions of the nonattainment area, we conclude that the State 

has met the applicable NSR requirements for the Phoenix-Mesa 

eight-hour ozone nonattainment area for the purposes of 

redesignation of the area for the 1997 eight-hour ozone 

standard. 

c. Conformity Requirements 

Under section 176(c) of the 1990 CAA Amendments, States are 

required to establish criteria and procedures to ensure that 
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steps to ensure the accuracy of this version, but it is not the official version. 

34 

federally-supported or funded projects conform to the air 

quality planning goals in the applicable SIP. Section 176(c) 

further provides that state conformity provisions must be 

consistent with federal conformity regulations that the CAA 

required EPA to promulgate. EPA’s conformity regulations are 

codified at 40 CFR Part 93, subparts A (referred to herein as 

transportation conformity) and B (referred herein as general 

conformity). Transportation conformity applies to transportation 

plans, program, and projects developed, funded, and approved 

under title 23 U.S.C. or the Federal Transit Act. General 

Conformity applies to all other federally-supported or funded 

projects. SIP revisions intended to address conformity 

requirements are referred to herein as conformity SIPs. 

The State of Arizona has adopted general conformity 

procedures, approved by EPA on April 23, 1999 (65 FR 19916).27

The State-adopted transportation conformity procedures, found at 

Arizona Revised Statutes (ARS), Title 18, Chapter 2, Article 14, 

have not yet been approved by EPA. EPA, however, believes it is 

reasonable to interpret the conformity SIP requirements as not 

applying for the purposes of a redesignation request under 

section 107(d)(3)(E) because state conformity rules are still 

 

27 In August 2005, Congress passed the Safe, Accountable, Flexible, 

Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU), which 

eliminated the requirement for States to adopt and submit conformity SIPs 

addressing general conformity requirements. See 75 FR 17254 (April 5, 2010) 

for conforming changes to EPA’s general conformity regulations.
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35 

required after redesignation and federal conformity rules apply 

where state rules have not been approved. 28 

C. The Area Must Show the Improvement in Air Quality is Due to 

Permanent and Enforceable Emission Reductions 

Section 107(d)(E)(iii) precludes redesignation of a 

nonattainment area to attainment unless EPA determines that the 

improvement in air quality is due to permanent and enforceable 

reductions in emissions resulting from the implementation of the 

applicable SIP, applicable federal air pollution control 

regulations, and other permanent and enforceable regulations. 

Under this criterion, the State must be able to reasonably 

attribute the improvement in air quality to emissions reductions 

that are permanent and enforceable. Attainment resulting from 

temporary reductions in emission rates (e.g., reduced production 

or shutdown due to temporary adverse economic conditions) or 

unusually favorable meteorology would not qualify as an air 

quality improvement due to permanent and enforceable emission 

reductions. 

In our proposed (70 FR 13425, March 21, 2005) and final (70 

FR 34362, June 14, 2005) redesignation rules for the Phoenix 

metropolitan 1-hour ozone nonattainment area, we described the 

numerous stationary source and mobile source control measures 

that were approved as part of the Arizona SIP and that, together 

 

28 See Wall v. EPA, 265 F.3d 426, 439 (6th Cir. 2001) upholding this 

interpretation. 
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36 

with certain federal measures, had provided for attainment of 

the 1-hour ozone standard through permanent and enforceable 

emissions reductions. See, e.g., the table of VOC RACT rules on 

page 13433 of our proposed 1-hour ozone redesignation rule at 

13425. Significant mobile source control measures that 

contributed to attainment and provide for maintenance of the 1-

hour ozone standard included low volatility cleaner burning 

gasoline, the federal motor vehicle and nonroad control 

programs, and implementation of an enhanced vehicle emissions 

inspection (VEI) program. See 70 FR 13425 at page 13430. 

The State of Arizona has relied on these same permanent and 

enforceable measures to attain the 1997 8-hour ozone standard 

but added an additional stationary source rule to the control 

strategy, Maricopa County rule 358 (“Polystyrene Foam 

Operations”), which EPA approved at 70 FR 30370 (May 26, 2005). 

In the approved Eight-Hour Ozone Attainment Plan, MAG quantified 

the emissions reduction from certain specific State and local 

measures, including VEI enhancements, local transportation 

improvements, summer gasoline formulation, and a rule governing 

polystyrene foam operation, as totaling 6.0 mtpd of VOC in 2008 

(a 2.4 percent reduction compared to the 2002 base case) and 

13.4 mtpd of NOX (a 4.6 percent reduction compared to the 2002 

base case). These reductions have contributed to the overall 
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37 

reduction in emissions that have provided for attainment of the 

1997 8-hour ozone standard in the Phoenix-Mesa area. 

The Eight-Hour Ozone Maintenance Plan relies on monitoring 

data (see figure 2-2 in the plan) showing a general downward 

trend in 8-hour ozone concentrations in the Phoenix-Mesa area 

from 2000 through 2008 despite increases of more than 15 percent 

in population, employment and vehicle travel, as evidence that 

the improvement in air quality can reasonably be attributed to 

the permanent and enforceable emissions reductions from the 

measures described above. 

In addition, we reviewed temperature data for Phoenix over 

this time period to determine if unusual meteorological 

conditions could have played a significant role in attaining the 

1997 8-hour ozone standard in the Phoenix-Mesa area. However, we 

did not observe any anomaly over this period relative to longterm averages.29 The period from 2002 to 2008 did not show a 

trend in declining air temperatures that would suggest that the 

observed trend in ozone concentrations was a result of favorable 

meteorology. We do recognize that a significant economic 

slowdown occurred nationally starting in 2008, and that the 

Phoenix-Mesa area was affected, but we note that the downward 

 

29 See memorandum from Rynda Kay, Air Quality Analysis Office, Air Division, 

EPA Region IX, entitled “Meteorological Trend Analysis for Phoenix-Mesa 

Area,” dated November 22, 2013, included in the docket for this rulemaking. 
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38 

trend in ozone concentrations had already been established well 

before that time.30

Based on the evidence discussed above, EPA finds that the 

improvement in air quality in the Phoenix-Mesa nonattainment 

area is the result of permanent and enforceable emission 

reductions from implementation of a combination of control 

measures. As such, we propose to find that the criterion for 

redesignation set forth at CAA section 107(d)(e)(E)(iii) is 

satisfied. 

D. The Area Must Have a Fully Approved Maintenance Plan Under 

CAA Section 175A. 

Section 175A of the CAA sets forth the elements of a 

maintenance plan for areas seeking redesignation from 

nonattainment to attainment. We interpret this section of the 

Act to require, in general, the following core elements: 

attainment inventory, maintenance demonstration, monitoring 

network, verification of continued attainment, and contingency 

plan. See Calcagni memo, pages 8 through 13. 

Under CAA section 175A, a maintenance plan must demonstrate 

continued attainment of the applicable NAAQS for at least ten 

years after EPA approves a redesignation to attainment. Eight 

years after redesignation, the State must submit a revised 

maintenance plan that demonstrates continued attainment for the 

 

30 Id.
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39 

subsequent ten-year period following the initial ten-year 

maintenance period. To address the possibility of future NAAQS 

violations, the maintenance plan must contain such contingency 

provisions that EPA deems necessary to promptly correct any 

violation of the NAAQS that occurs after redesignation of the 

area. Based on our review and evaluation of the plan, as 

detailed below, we are proposing to approve the Eight-Hour Ozone 

Maintenance Plan because we believe that it meets the 

requirements of CAA section 175A. 

1. Attainment Inventories and Projected Future Inventories 

A maintenance plan for the 1997 8-hour ozone standard must 

include an inventory of emissions of ozone precursors (VOC and 

NOx) in the area in order to identify a level of emissions that 

are sufficient to attain the 1997 8-hour ozone NAAQS. This 

inventory must be consistent with EPA’s most recent guidance on 

emissions inventories for nonattainment areas available at the 

time of plan submittal and should represent emissions during the 

time period associated with the monitoring data showing 

attainment. The inventory must also be comprehensive, including 

emissions from stationary point sources, area sources, nonroad 

mobile sources, and on-road motor vehicle sources, and must be 

based on actual “ozone season data,” i.e., summertime emissions. 

MAG selected year 2005 as the year for the attainment 

inventory in the Eight-Hour Ozone Maintenance Plan. As shown in 
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40 

table 2, the area attained the 1997 8-hour ozone standard at the 

end of 2007 based on monitoring data collected over the course 

of the previous three-year period (2005-2007) during which the 

calculated design value was less than the standard. The 

attainment inventory will generally be the actual inventory 

during the time period the area attained the standard, and year 

2005 was one of the years from the three-year period for which 

the area first attained the standard. Thus, MAG’s selection of 

2005 for the attainment inventory is acceptable. 

Table 2: Eight-Hour Ozone Design Values in the Phoenix-Mesa 

Nonattainment Area 

Site Agency 

Design Value* (parts per million) 

2005-07 2006-08 2007-09 2008-10 2009-11 2010-12 

Apache 

Junction 

PCAQCD 0.076 0.080 0.075 0.073 0.072 0.074 

Blue Point MCAQD 0.067 0.064 0.067 0.070 0.072 0.075 

Buckeye MCAQD 0.065 0.066 0.064 0.064 0.064 0.066 

Cave Creek MCAQD 0.079 0.078 0.075 0.074 0.075 0.077 

Central 

Phoenix 

MCAQD 0.075 0.074 0.070 0.071 0.071 0.074 

Dysart MCAQD 0.067 0.067 0.066 0.068 0.070 0.071 

Falcon 

Field 

MCAQD 0.076 0.075 0.071 0.070 0.068 0.069 

Fountain 

Hills 

MCAQD 0.082 0.079 0.074 0.074 0.073 0.076 

Glendale MCAQD 0.075 0.074 0.071 0.072 0.072 0.076 

High School SRPMIC 0.077** 0.076** 0.073 0.072 0.072 0.074 

Humboldt 

Mountain 

MCAQD 0.081 0.078 0.074 0.071 0.071 0.075 

JLG 

Supersite 

ADEQ 0.076 0.076 0.075 0.075 0.075 0.076 

Lehi SRPMIC 0.079** 0.074 0.074 0.073 0.072 0.073 

North 

Phoenix 

MCAQD 0.082 0.081 0.076 0.077 0.077 0.081 
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41 

Pinnacle 

Peak 

MCAQD 0.078 0.074 0.072 0.073 0.074 0.077 

Red 

Mountain 

SRPMIC 0.083 0.080 0.076 0.076 0.076 0.077 

Rio Verde MCAQD 0.083 0.080 0.075 0.072 0.073 0.074 

Senior 

Center 

SRPMIC 0.076 0.075 0.072 0.072 0.072 0.074 

South 

Phoenix 

MCAQD 0.072 0.072 0.071 0.072 0.072 0.076 

South 

Scottsdale 

MCAQD 0.078 0.077 0.075 0.074 0.074 0.077 

Tempe MCAQD 0.077 0.077 0.073 0.071 0.068 0.070 

West 

Chandler 

MCAQD 0.076 0.076 0.073 0.073 0.072 0.074 

West 

Phoenix 

MCAQD 0.074 0.078 0.073 0.073 0.073 0.078 

* The design value is the three-year average of the annual fourth-highest 

daily maximum 8-hour average ozone concentration. 

** Design values do not meet the completeness requirements of 40 CFR part 50 

appendix I. 

 

The attainment year emission inventory for 2005 in the 

Eight-Hour Ozone Maintenance Plan is generally consistent with 

the 2005 Periodic Emission Inventory (PEI) emissions estimates 

for Maricopa County and the Phoenix-Mesa nonattainment area. The 

PEI was calculated in terms of annual emissions and ozone 

season-day emissions. 

Emissions from point sources were estimated from each 

identified facility through permit system databases and annual 

emissions reports submitted to the facility’s permitting 

authority. Emissions from area sources were estimated by source 

category using information from permit databases and previous 

SIP inventories. MAG estimated nonroad mobile source emissions 

using EPA’s NONROAD2005 model, and estimated on-road motor 

vehicle source emissions using EPA’s MOBILE6.2 model. On-road 
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42 

vehicle emissions estimates reflect estimates of vehicle miles 

traveled (VMT) using data from U.S. Department of 

Transportation’s 2005 Highway Performance and Monitoring System. 

Biogenic emissions of NOX and VOC were calculated using the Model 

of Emissions of Gases and Aerosols from Nature (MEGAN) with 

input including emissions rates developed from measurements made 

of the dominant plant species in Maricopa County, locations and 

biomass densities of the dominant plant species, and surface 

temperature data. See 2005 Periodic Emissions Inventory for 

ozone precursors in volume 1 of the appendices to the Eight-Hour 

Ozone Maintenance Plan. 

For the Eight-Hour Ozone Maintenance Plan, MAG adjusted and 

supplemented the 2005 PEI ozone precursor emissions estimates 

developed using the methods described above to develop emissions 

estimates for an area referred to as the inner modeling domain 

(“modeling domain”), a rectangular area encompassing all of the 

nonattainment area and largely defined by the boundaries of the 

irregularly-shaped nonattainment area. See figure II-1 of MAG’s 

technical support document (TSD) for the Eight-Hour Ozone 

Maintenance Plan for an illustration of the modeling domain. The 

modeling domain defines the area for which MAG modeled ozone 

concentrations. 

MAG developed modeling-domain emissions estimates for 2005 

for the June, July, and August episodes that were modeled for 
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43 

the approved Eight-Hour Ozone Attainment Plan. See table 3 below 

for a summary of modeling domain emissions estimates by source 

category for year 2005 for the June modeling episode. The 2005 

attainment year inventory includes credit for committed control 

measures that were in place during the summer of 2005. See table 

3-5 of the Eight-Hour Ozone Maintenance Plan. 

Table 3: 2005 and Projected 2019 and 2025 VOC and NOx Emissions 

for the Phoenix-Mesa Modeling Domain for June Ozone Episode 

(metric tons per day)a

Source Category

NOx VOC 

2005 2019 2025 2005 2019 2025

Point 10.9 58.6 59.1 11.1 16.7 18.7

Area 19.6 27.7 31.1 79.2 111.4 124.8

Nonroad Mobile 77.7 43.9 37.9 40.3 48.7 31.8

On-road Motor 

Vehicles 154.3 125.8 109.8 72.1 30.9 47.9

Biogenics 8.6 8.6 8.6 451.3 451.3 451.3

Total 271.1 264.4 246.4 653.9 659.0 674.4

a Emissions reflect a specific day of the week (Thursday) during the June 

ozone episode. 

Sources: Eight-Hour Ozone Maintenance Plan at tables 3-6 and 3-7; table 1 of 

the Maintenance Plan Supplement. 

As shown in table 3, in the 2005 attainment year inventory 

for the modeling domain, biogenic sources contributed 

approximately 70 percent to total VOC emissions. In contrast, 

on-road motor vehicles dominated the total NOX emissions and 

accounted for 60 percent of total NOX. 

In addition to 2005 values, table 3 above also summarizes 

MAG’s VOC and NOX emissions estimates for an interim year (2019) 

and the maintenance plan’s horizon year (2025). The projected 

emission inventories for 2019 and 2025 were based on the use of 
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44 

growth factors, on-going emissions control programs, and 

retirement rates for obsolete sources. The Eight-Hour Ozone 

Maintenance Plan includes MAG’s 2025 emissions estimates and 

related documentation, while MAG’s 2019 interim-year emissions 

estimates and documentation are found in a separate MAG 

document, entitled “Analysis of the Interim Year 2019 as a 

Supplement to the 2009 MAG Eight-Hour Ozone Redesignation 

Request and Maintenance Plan for the Maricopa Nonattainment 

Area,” dated June 17, 2013 (“Maintenance Plan Supplement”). 

MAG used growth factors to project emissions in 2019 and 

2025 for point and area sources based on population and 

employment projections approved by the MAG Regional Council in 

May 2007. MAG included population and employment growth 

projections for 2016 and 2021 in the Maintenance Plan Supplement 

and projected emissions for 2019 from interpolation of the 

projected emissions for 2016 and 2021. MAG used a compound 

annual growth rate for population of 2.6 percent between 2005 

and 2016. The actual compound annual growth rate between 2005 

and 2011, based on the 2005 Special Census for Maricopa County 

and the 2010 Census, was 0.8 percent. Because the population of 

Maricopa County grew more slowly than projected, MAG expects the 

emission inventories related to the socioeconomic projections 

for the interim and horizon years to be conservatively 

overestimated. 
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MAG used different growth factors for different source 

types within each source category (e.g., specific stationary 

point sources excluding power plants, specific categories of 

area sources such as dry cleaners). For nonroad mobile sources, 

MAG derived growth factors from the EPA NONROAD2005 model 

defaults for Maricopa County. The growth factors are listed in 

Appendix IV-vii to Appendix A, Exhibit 2 of the Eight-Hour Ozone 

Maintenance Plan and generally range from 1 to 1.8. For power 

plants, MAG estimated future emissions based on the facility’s 

potential to emit (PTE), i.e., the maximum levels allowed under 

existing permits. MAG estimated on-road motor vehicle emissions 

based on the same population and employment projections used to 

estimate point and area sources, but increased on-road source 

emissions of VOC and NOX by 10 percent to provide safety margins 

for the motor vehicle emission budgets for transportation 

conformity. 

For biogenic emissions, the 2005 inventory was held 

constant for 2019 and 2025. In the approved Eight-Hour Ozone 

Attainment Plan, MAG similarly held biogenic emissions constant, 

compared to the 2002 base year inventory, when demonstrating 

attainment with the standard by 2008 (see tables 5-3 and 5-4 in 

the Eight-Hour Ozone Attainment Plan). In additional information 

provided to EPA during our review of the Eight-Hour Ozone 

Attainment Plan, MAG explained that no projected land use or 
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46 

land cover data was available for the 2008 attainment year, 

therefore biogenic emissions in the ozone modeling domain were 

held constant. As discussed in greater detail in our proposed 

rulemaking to approve the Eight-Hour Ozone Attainment Plan, MAG 

expected that the trend of increasing urbanization in the 

Phoenix-Mesa nonattainment area would be expected to decrease 

biogenic VOC emissions in Maricopa County. Because MAG did not 

have 2008 land use data available, it determined that 

maintaining constant biogenic emissions of the ozone precursors 

would be more conservative than attempting to estimate the 

anticipated decrease in biogenic VOC emissions. See 77 FR 21690 

at 21694 (April 11, 2012). This rationale similarly applies to 

the use of a constant biogenic emissions value for each ozone 

episode in the Eight-Hour Ozone Maintenance Plan. 

The Eight-Hour Ozone Maintenance Plan builds upon the 

control strategy developed for attainment and maintenance of the 

1-hour ozone standard and the control strategy developed for 

attainment of the 1997 8-hour ozone standard. The plan 

specifically cites and quantifies the emissions reductions from 

seven control measures for maintenance demonstration purposes in 

the Phoenix-Mesa area through year 2025. These measures include 

one federal control measure, a measure referred to as “Federal 

Nonroad Equipment Emission Standards,” and six State or local 

control measures. All of these measures have been approved into 
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47 

the Arizona SIP, or, in the case of the federal nonroad 

equipment emission standards, have been promulgated by EPA as 

regulations published in the CFR: 

· Summer fuel reformulation, approved as part of Arizona’s 

cleaner burning gasoline regulations at 69 FR 10161 (March 

4, 2004); 

· Phased-In emission test cutpoints and one-time waiver from 

vehicle emissions test, approved as part of the Arizona 

vehicle emissions inspection and maintenance program at 69 

FR 2912 (January 22, 2003); 

· Tougher enforcement of vehicle registration and emission 

test compliance, as set forth in ARS 49-552 (“Enforcement 

on city, town, county, school district or special district 

property”), approved at 70 FR 11553 (March 9, 2005); and 

49-541.01 (paragraphs D and E)31 (“Vehicle emissions 

inspection program; constant four wheel drive vehicles; 

requirements; location; violation; classification; 

penalties; new program termination”), approved at 70 FR 

11553 (March 9, 2005); 

· Federal (tier 4) nonroad equipment emissions standards, 

promulgated in 40 CFR part 1039 at 69 FR 38958 (June 29, 

2004); 

 

31 These provisions are now codified in ARS 49-550 (“Violation; 

Classification; Civil Penalty”). 
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48 

· Expansion of Area A boundaries, as set forth in ARS 49-541 

(“Definitions”), approved at 78 FR 30209 (May 22, 2013); 

and 

· Ban open burning during the ozone season, as set forth in 

ARS 49-501 (“Unlawful open burning; exceptions; fine; 

definition”), approved in a final rule signed by the EPA 

Region IX Regional Administrator on December 16, 2013 (not 

yet published in the Federal Register). 

Table 4 shows the projected emission reductions developed 

by MAG from the seven maintenance measures during the June ozone 

episode. Of the seven maintenance measures in the Phoenix-Mesa 

Maintenance Plan, the federal nonroad equipment emission 

standards represents the largest reduction in VOC and NOX

emissions from an individual maintenance measure. 

Table 4: 2025 Emission Reductions from Individual Maintenance 

Measures in the Phoenix-Mesa 8-Hour Ozone Modeling Domain

 

VOC NOX

Maintenance Measure 

Reduction 

(metric 

tons per 

day) 

Percent 

Reduction in 

Anthropogenic 

Emissions 

Reduction 

(metric 

tons per 

day) 

Percent 

Reduction in 

Anthropogenic 

Emissions 

Summer Fuel Reformulation 1.3 0.5 0.4 

(increase)

0.1 

(increase) 

Phased-In Emission Test 

Cutpoints 

< 0.1 < 0.1 < 0.1 < 0.1 

One-Time Waiver from 

Vehicle Emissions Test 

0.2 < 0.1 0.3 0.1 

Tougher Enforcement of 

Vehicle Registration and 

Emission Test Compliance 

0.2 < 0.1 0.4 0.1 

Federal Nonroad Equipment 

Emission Standards 

19.3 7.9 47.2 16.5 

Expansion of Area A 

Boundary 

0.2 < 0.1 0.4 0.1 
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49 

Ban Open Burning During 

Ozone Season 

< 0.1 < 0.1 < 0.1 < 0.1 

Source: Eight-Hour Ozone Maintenance Plan, table 3-2. 

As shown in table 3, NOX emissions from point sources is 

projected to increase dramatically between 2005 and the interim 

and horizon years of 2019 and 2025, primarily due to MAG’s 

conservative assumption that power plants in the future would 

operate at their PTE. Emissions of NOX from area sources are also 

estimated to be higher in the interim and horizon years. MAG 

projected that emissions from nonroad sources would decrease due 

to the implementation of federal emission standards for nonroad 

equipment (see Table 4). Emissions of NOx from on-road motor 

vehicles are also projected to decrease notwithstanding the 10% 

increase added to the 2025 motor vehicle emissions estimates (to 

provide for a safety margin for transportation conformity 

purposes), due to the continuing benefit of the federal motor 

vehicle control program and the turnover of older model cars to 

newer models designed to meet more stringent EPA emissions 

standards. Overall, between 2005 and 2025, MAG projected total 

emissions of NOX to decrease by nearly 25 mtpd for the June ozone 

episode. 

As shown in table 3, MAG projected that VOC emissions from 

point and area sources will increase over the 2005 to 2025 time 

frame. Emissions from VOC from nonroad and on-road mobile 

sources are projected to decrease between 2005 and 2025, 
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50 

notwithstanding the 10% safety margin added to 2025 motor 

vehicle emissions estimates for the same reasons given above for 

NOx. Emissions of biogenic VOC are projected to remain constant, 

as discussed above. Overall, MAG projected total emissions of 

VOC in 2025 to increase by approximately 20 mtpd for the June 

ozone episode as compared to 2005. 

Based on our review of the emission inventories (and 

related documentation) from the Eight-Hour Ozone Maintenance 

Plan, we find that the inventory for 2005 is comprehensive, that 

the methods and assumptions used by MAG to develop the 2005 

emission inventory are reasonable, and that the inventory 

reasonably estimates actual ozone season emissions in an 

attainment year. Moreover, we find that the 2005 emission 

inventory reflects the latest planning assumptions and emission 

models available at the time the plan was developed, and provide 

a comprehensive and reasonably accurate basis upon which to 

forecast ozone precursor emissions for years 2019 and 2025. 

2. Maintenance Demonstration 

CAA section 175A(a) requires that the maintenance plan 

“provide for the maintenance of the national primary ambient air 

quality standard for such air pollutant in the area concerned 

for at least 10 years after the redesignation.” Generally, a 

state may demonstrate maintenance of the 1997 ozone standard by 

either showing that future emissions will not exceed the level 
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51 

of the attainment year inventory or by modeling to show that the 

future mix of sources and emissions rates will not cause a 

violation of the NAAQS. For areas that are required under the 

Act to submit modeled attainment demonstrations, the maintenance 

demonstration should generally use the same type of modeling as 

used for the attainment demonstration. See Calcagni memo, page 

9. 

On June 13, 2012 (77 FR 35286), EPA published a final 

approval of the Eight-Hour Ozone Attainment Plan, which 

demonstrated attainment of the 1997 8-hour ozone NAAQS in the 

Phoenix-Mesa nonattainment area by June 15, 2009. Consistent 

with EPA’s “Guidance on the Use of Models and Other Analyses for 

Demonstrating Attainment of Air Quality Goals for the 8-Hour 

Ozone and PM2.5 NAAQS and Regional Haze” (“EPA Modeling 

Guidance”), the Eight-Hour Ozone Attainment Plan included the 

following components: a conceptual description of the area’s 

nonattainment problem, a modeling protocol, model selection and 

set-up, selection and evaluation of ozone episodes to model, 

meteorological and emissions input data preparation, model 

performance evaluations for the photochemical and meteorological 

models, the modeled attainment test, and a weight of evidence 

evaluation. See Eight-Hour Ozone Attainment Plan, chapter 3 and 

appendix A, exhibit 2. EPA evaluated these components and found 
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52 

that they provided an adequate basis for the attainment 

demonstration. See 77 FR 21690, at 21697-21699. 

For the modeled 10-year maintenance test, MAG selected the 

same photochemical and meteorological-input models and set-up 

and the same high-ozone episodes to model as evaluated in the 

Eight-Hour Ozone Attainment Plan. As such, we are not 

reassessing the modeling protocol, choice of ozone episodes, and 

model performance. Here, the model was used to predict the 

effect of changes in emissions due to land use changes, growth, 

and the effect of control measures from a baseline emission year 

of 2005 to maintenance years 2019 and 2025.32 The resulting 

concentrations were used to evaluate the impact of emission 

changes during the high-ozone episode-specific meteorological 

conditions. See Eight-Hour Ozone Maintenance Plan (chapter 3 and 

appendix A, exhibit 2) and the Maintenance Plan Supplement. 

Under EPA Modeling Guidance, the model is used to develop 

relative response factors (RRFs) that give the model’s response 

to emission changes, and the RRFs are applied to monitored 

design value concentrations to arrive at the predicted future 

concentrations. The particulars of the calculation, and which 

model grid cells and modeled days are to be included, are 

specified in the EPA Guidance. See EPA Modeling Guidance, pages 

 

32 We evaluate the emissions inventory for the baseline and maintenance years 

in section V.D.1., above. 
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53 

15, 25, and 155. MAG assessed the 2019 and 2025 effects and 

found the maximum predicted ozone design value to be 0.081 parts 

per million (ppm) in 2019 and 0.081 ppm in 2025. All values 

equal to or less than 0.084 ppm meet the 1997 8-hour ozone 

NAAQS, and thus, the modeling results predict continued 

maintenance of the 1997 8-hour ozone NAAQS in the Phoenix-Mesa 

area for at least ten years beyond redesignation (assuming 

redesignation of the area before 2016). 

In addition to a modeled maintenance demonstration, which 

focuses on locations with an air quality monitor, EPA generally 

requires an unmonitored area analysis. This analysis is intended 

to ensure that a control strategy leads to maintenance of the 

NAAQS in other locations that have no monitor but that might 

have base year (and/or future year) ambient ozone levels 

exceeding the NAAQS. The unmonitored area analysis uses a 

combination of model output and ambient data to identify areas 

that might exceed the NAAQS if monitors were located there. In 

order to examine unmonitored areas in all portions of the 

modeling domain, EPA recommends use of interpolated spatial 

fields of ambient data combined with gridded modeled outputs. 

See EPA Modeling Guidance, page 29. MAG used the EPA developed 

Modeled Attainment Test Software (MATS) Version 2.0.1 to conduct 

this analysis. The maximum design values from this analysis were 
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54 

0.083 ppm in 2019 and 0.083 ppm in 2025, i.e., in attainment of 

the 1997 8-hour ozone NAAQS. See Maintenance Plan Supplement. 

Based on our prior approval of MAG’s photochemical modeling 

approach for 8-hour ozone attainment demonstration purposes and 

because we find MAG’s application of the same basic approach to 

the 8-hour ozone maintenance demonstration to be reasonable, we 

accept the results of MAG’s modeling as a sufficient 

demonstration that the plan provides for maintenance of the 1997 

8-hour ozone NAAQS in the Phoenix-Mesa area through the first 

ten years after redesignation to attainment. Therefore, we 

propose to find that the Eight-Hour Ozone Maintenance Plan meets 

the maintenance demonstration requirements under CAA section 

175A(a). 

3. Monitoring Network 

Continued ambient monitoring of an area is generally 

required over the maintenance period. As discussed in section 

V.A. of this document, ozone is currently monitored by ADEQ, 

MCAQD, and PCAQCD at a total of 20 sites within the Phoenix-Mesa 

1997 8-hour ozone nonattainment area. ADEQ and MCAQD monitors 

represent 19 of the 20 sites. 

The Eight-Hour Ozone Maintenance Plan (see page 3-21 of the 

plan) indicates that ADEQ and MCAQD will continue to operate an 

appropriate air quality monitoring network in accordance with 40 

CFR part 58 to verify continued attainment of the 1997 8-hour 
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55 

ozone NAAQS. Further, if there is significant change to 

parameters such as population, vehicle miles of travel, or 

significant sources, ADEQ and MCAQD will undertake studies to 

determine if it is appropriate to re-site monitors or add 

additional monitors to the network. Lastly, the Eight-Hour Ozone 

Maintenance Plan takes note of the annual review by EPA of State 

and local ambient monitoring network plans under 40 CFR part 58 

as providing a continuing means for ensuring the adequacy of the 

ozone monitoring network in the Phoenix-Mesa area. 

We note that PCAQCD is not cited in the subsection on an 

approved monitoring network and verification of continued 

attainment in the Eight-Hour Maintenance Plan, but find the 

failure to include PCAQCD in the plan’s discussion of continued 

monitoring and verification of continued attainment to be 

harmless error because the applicable monitoring requirements in 

40 CFR part 58 will continue to apply to PCAQCD’s ozone monitor 

regardless of our approval of the maintenance plan and 

redesignation request and because the overall ozone monitoring 

network operated by ADEQ and MCAQD alone (i.e., 19 of 20 NAMS 

and SLAMS stations) is sufficient to meet ozone monitoring 

requirements in the Phoenix-Mesa are. Therefore, for the reasons 

given above, EPA finds that the Eight-Hour Maintenance Plan 

adequately provides for continued ambient ozone monitoring in 

the Phoenix-Mesa area. 
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4. Verification of Continued Attainment 

Each State should ensure that it has the legal authority to 

implement and enforce all measures necessary to attain and to 

maintain the NAAQS. Previously, in taking action to approve the 

various measures that the State is relying on for attainment and 

maintenance of the 1997 8-hour ozone NAAQS, such as the cleaner 

burning gasoline regulations and the vehicle emissions 

inspection (VEI) program, we determined that the State has the 

necessary legal authority to implement and enforce the measures 

and find no sunset clauses that would be triggered for these 

control measures upon redesignation to attainment. We are, 

however, aware of Arizona Revised Statutes (ARS) section 41-

3017.01 which provides for the termination of the VEI on January 

1, 2017, but recognize that the Arizona Legislature has at 

various intervals in the past extended the termination date for 

the VEI program and expect it to do so again before 2017. We 

also find that the applicable State, regional, and county 

agencies, such as ADEQ, the Arizona Department of Weights and 

Measures, Arizona Department of Transportation (DOT), MAG, 

Maricopa County, Pinal County, and local cities and towns, have 

the necessary authority to adopt, implement, and enforce any 

emission control contingency measures determined to be necessary 

to correct ozone NAAQS violations. 
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To verify continued attainment, in addition to continuing 

to operate an ozone monitoring network that meets EPA ambient 

air quality surveillance requirements, MCAQD will continue to 

update the emissions inventory for ozone precursors in the 

Phoenix-Mesa area every three years with input and assistance 

from ADEQ, Arizona DOT, and MAG. These emissions inventory 

updates will provide a means with which to track emissions 

relative to those projected in the maintenance plan, and thereby 

verify the continued attainment of the NAAQS. 

Lastly, the transportation conformity process, which 

requires a comparison of on-road motor vehicle emissions that 

would occur under new or amended transportation plans and 

programs with the motor vehicle emissions budgets in the EightHour Ozone Maintenance Plan, represents another means by which 

to verify continued attainment of the 1997 8-hour ozone NAAQS in 

the Phoenix-Mesa area, given the importance of motor vehicle 

emissions to the overall emissions inventories of ozone 

precursors. See pages 3-14 and 3-15 of the Eight-Hour Ozone 

Maintenance Plan. These methods are sufficient for the purpose 

of verifying continued attainment. 

5. Contingency Provisions 

Section 175A(d) of the Act requires that maintenance plans 

include contingency provisions, as EPA deems necessary, to 

promptly correct any violations of the NAAQS that occur after 
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steps to ensure the accuracy of this version, but it is not the official version. 

58 

redesignation of the area. Such provisions must include a 

requirement that the State will implement all measures (with 

respect to the control of the air pollutant concerned) that were 

contained in the SIP for the area before redesignation of the 

area as an attainment area. 

Under section 175A(d), contingency measures identified in 

the contingency plan do not have to be fully adopted at the time 

of redesignation. However, the contingency plan is considered to 

be an enforceable part of the SIP and should ensure that the 

contingency measures are adopted expeditiously once they are 

triggered by a specified event. The maintenance plan should 

clearly identify the measures to be adopted, a schedule and 

procedure for adoption and implementation, and a specific 

timeline for action by the State. As a necessary part of the 

plan, the State should also identify specific indicators or 

triggers that will be used to determine when the contingency 

measures need to be implemented. 

As required by section 175A of the CAA, MAG adopted a 

contingency plan to address possible future ozone air quality 

problems. See page 3-21 of the Eight-Hour Ozone Maintenance 

Plan. The plan includes both specific contingency measures that 

have already been adopted and are being implemented early33 and a 

 

33 MAG followed the August 13, 1993 EPA guidance memorandum entitled “Early 

Implementation of Contingency Measures for Ozone and Carbon Monoxide (CO) 

Nonattainment Areas.” 
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mechanism to trigger the adoption of additional measures as 

needed. The specific contingency measures, which are described 

in more detail in section IV-7-2 of MAG’s TSD for the Eight-Hour 

Ozone Maintenance Plan (appendix A, exhibit 2 of the plan), are: 

· Gross Polluter Option for I/M Program Waivers; 

· Increased Waiver Repair Limit Options; 

· Federal Heavy Duty Diesel Vehicle Emissions Standards; 

· Coordinate Traffic Signal Systems; 

· Develop Intelligent Transportation Systems; and 

· Liquid Leaker Test as Part of Vehicle Emissions Inspection 

Program. 

Two of the measures, “coordinate traffic signal systems” and 

“develop intelligent transportation systems,” are control 

measures that the Eight-Hour Ozone Attainment Plan had relied 

upon to demonstrate attainment of the standard. As noted above, 

CAA section 175A(d) requires contingency plans to include a 

requirement that the State will implement all measures with 

respect to the control of the air pollutant concerned that were 

contained in the SIP for the area before redesignation of the 

area as an attainment area, i.e., if triggered under the terms 

of the contingency plan. In the case of these two specific 

contingency measures, we do not believe that the contingency 

plan must include a specific requirement to resume their 
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steps to ensure the accuracy of this version, but it is not the official version. 

60 

implementation, i.e., if triggered, because the measures 

themselves continue to be implemented by the relevant agencies. 

The Eight-Hour Ozone Maintenance Plan simply does not rely on 

emissions reductions from them to demonstrate maintenance 

through 2025. The emissions reductions from the other 

contingency measures listed above are also not included in the 

projected emissions inventory, and no emission reduction credit 

was taken for these measures in the modeling for the maintenance 

demonstration. As noted in the maintenance plan, implementation 

of these measures should provide additional assurance that the 

1997 ozone standard will be maintained through 2025. 

In addition to the previously implemented contingency 

measures listed above, the plan includes a commitment to examine 

ambient air quality data to determine if additional contingency 

measures are needed. If the three-year average of the annual 

fourth highest daily 8-hour ozone concentration exceeds 84 parts 

per billion at any ozone monitor, additional control measures 

will be considered. The plan requires that (1) the monitoring 

data will be verified within three months after the activation 

of the trigger; (2) control measures will be considered for 

adoption six months after the date established in (1); and (3) 

the resultant committed measures will be implemented within six 

to twelve months, depending on the time needed to put the 

measures in place. 
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61 

Upon our review of the plan, as summarized above, we find 

that the contingency provisions of the Eight-Hour 

Ozone Maintenance Plan identify specific contingency measures, 

contain tracking and triggering mechanisms to determine when 

contingency measures are needed, and contain specific timelines 

for action. Accordingly, we conclude that the contingency 

provisions of the Eight-Hour Ozone Maintenance Plan are adequate 

to ensure prompt correction of a violation and therefore comply 

with section 175A(d) of the Act. 

6. Subsequent Maintenance Plan Revisions 

CAA section 175A(b) provides that States shall submit a SIP 

revision eight years after redesignation that provides for 

maintaining the NAAQS for an additional ten years. The EightHour Ozone Maintenance Plan includes MAG’s commitment to prepare 

the revised maintenance plan eight years after redesignation to 

attainment. See page 3-22 of the Eight-Hour Ozone Maintenance 

Plan. 

7. Motor Vehicle Emissions Budgets 

Transportation conformity is required by section 176(c) of 

the CAA. Our transportation conformity rule (codified in 40 CFR 

part 93, subpart A) requires that transportation plans, 

programs, and projects conform to SIPs, and establishes the 

criteria and procedures for determining whether or not they do 

so. Conformity to the SIP means that transportation activities 
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steps to ensure the accuracy of this version, but it is not the official version. 

62 

will not produce new air quality violations, worsen existing 

violations, or delay timely attainment of the national ambient 

air quality standards or any interim milestones. 

Maintenance plan submittals must specify the emissions of 

transportation-related VOC and NOx emissions allowed in the last 

year of the maintenance period, i.e., the motor vehicle 

emissions budgets (MVEBs or budgets). The MVEBs serve as a 

ceiling on emissions that would result from an area's planned 

transportation system. The MVEB concept is further explained in 

the preamble to the November 24, 1993, transportation conformity 

rule (58 FR 62188). The preamble describes how to establish 

MVEBs in the SIP and how to revise the MVEBs if needed. 

The submittal must also demonstrate that these emissions 

levels, when considered with emissions from all other sources, 

are consistent with maintenance of the NAAQS. In order for us to 

find these emissions levels or “budgets” adequate and 

approvable, the submittal must meet the conformity adequacy 

provisions of 40 CFR 93.118(e)(4) and (5). For more information 

on the transportation conformity requirement and applicable 

policies on MVEBs, please visit our transportation conformity 

Web site at: 

http://www.epa.gov/otaq/stateresources/transconf/index.htm. 

EPA’s process for determining adequacy of a MVEB consists 

of three basic steps: (1) providing public notification of a SIP 
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submission; (2) providing the public the opportunity to comment 

on the MVEB during a public comment period; and (3) making a 

finding of adequacy based on our initial review of the submitted 

SIP. The process for determining the adequacy of a submitted 

MVEB is codified at 40 CFR 93.118. 

The availability of the SIP submission with MVEBs was 

announced for public comment on EPA’s Adequacy Web site on April 

27, 2009 at: 

http://www.epa.gov/otaq/stateresources/tansconf/currsips.htm, 

which provided a 30-day public comment period. The comment 

period for this notification ended on May 28, 2009, and EPA 

received no comments from the public. Note, however, that a 

second mechanism is also provided for EPA review and public 

comment on MVEBs, as described in 40 CFR 93.118(f)(2). This 

mechanism provides for EPA’s review of the adequacy of an 

implementation plan MVEB simultaneously with its review and 

approval or disapproval of the submitted plan itself. In this 

instance, EPA used the web notification discussed above to 

solicit public comments on the adequacy of the Phoenix-Mesa 

MVEBs in the Eight-Hour Ozone Maintenance Plan, but is taking 

comment on the approvability of the submitted MVEBs through this 

proposed rule. Any and all comments on the approvability of the 

Eight-Hour Ozone Maintenance Plan MVEBs should be submitted 
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during the comment period stated in the DATES section of this 

document. 

The Eight-Hour Ozone Maintenance Plan contains new VOC and 

NOx MVEBs for the Phoenix-Mesa area for 2025.34 MAG developed the 

budgets for the 2025 maintenance year by using geographic 

information systems (GIS) to separate the on-road motor vehicle 

emissions in the Phoenix-Mesa air quality planning area from the 

larger ozone modeling domain, resulting in MVEBs of 43.8 metric 

tons per day (mtpd) of VOC and 101.8 mtpd of NOx. The MVEBs 

include a 10% safety margin35 and correspond to the peak episode 

day (Thursday) in June 2025 that was used to model maintenance 

of the 1997 8-hour ozone NAAQS in the Phoenix-Mesa area in the 

Eight-Hour Ozone Maintenance Plan. 

To estimate motor vehicle emissions for the Eight-Hour 

Ozone Maintenance Plan and related MVEBs, MAG used the version 

of EPA’s motor vehicle emissions factor model (MOBILE6.2) that 

was current at the time the emissions estimates were prepared. 

The calculated emission factors were multiplied by the estimates 

 

34 The derivation of the MVEBs is discussed in MAG’s emissions inventory, 

which was included in the Eight-Hour Ozone Maintenance Plan submittal as 

Appendix A, Exhibit 1 (pages 99-110), and in Section IV-2 of MAG’s TSD, which 

was included in the Eight-Hour Ozone Maintenance Plan submittal as Appendix 

A, Exhibit 2. Additional discussion of the on-road emissions budgets is 

included in Section IV-9 of the TSD.

35 MAG increased the 2025 VOC and NOx emissions from on-road motor vehicle 

sources in the eight-hour ozone modeling domain in order to address the 

“inherent uncertainties associated with the use of the latest planning 

assumptions in conformity analyses.” MAG distributed the increase spatially 

“based on the proportion of onroad mobile emissions assigned to each four 

kilometer grid cell.” See page 3-20 of the Eight-Hour Ozone Maintenance 

Plan. 
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65 

of vehicle miles of travel (VMT) to generate emission estimates 

for on-road motor vehicle sources. The projected emissions 

inventory and related MVEBs take into account expected growth in 

VMT and reductions from the maintenance measures, but do not 

include reductions from implementation of the contingency 

measures. 

The MVEBs are consistent with the 2025 on-road motor 

vehicle source VOC and NOx emissions included in the Eight-Hour 

Ozone Maintenance Plan’s 2025 emission inventory, as summarized 

above in table 3, above. The conformity rule (40 CFR 93.124(a)) 

allows for a safety margin, and even with the 10 percent safety 

margin added to the on-road emissions, the overall emissions in 

the Phoenix-Mesa area are consistent with continued maintenance 

of the 1997 ozone standard. 

EPA is proposing to approve the MVEBs for 2025 as part of 

our approval of the Eight-Hour Ozone Maintenance Plan for the 

Phoenix-Mesa area. We have determined that the MVEB emission 

targets are consistent with emission control measures in the SIP 

and that the Phoenix-Mesa area can maintain the 1997 8-hour 

ozone NAAQS for ten years beyond redesignation. The details of 

EPA’s evaluation of the MVEBs for compliance with the budget 
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66 

adequacy criteria of 40 CFR 93.118(e) are provided in a separate 

memorandum included in the docket of this rulemaking.36

If we finalize this action as proposed, we will make the 

adequacy finding for the 2025 MVEBs in the final rule in which 

we approve the Eight-Hour Ozone Maintenance Plan. Pursuant to 40 

CFR 93.118(f)(2)(iii), our adequacy finding will be effective 

upon publication of the final rule in the Federal Register. Once 

found adequate, MAG and the U.S. Department of Transportation 

must use these new budgets for 2025 in conformity analyses with 

applicable horizon years after 2024. The 2008 MVEBs established 

in MAG’s Eight-Hour Ozone Attainment Plan, which EPA previously 

approved (77 FR 35285), also remain in effect. On-road motor 

vehicle emissions in any required analysis years up to and 

including 2024 cannot exceed levels established by those 

previously-approved MVEBs. 

VI. Proposed Action and Request for Public Comment 

Under CAA section 110(k)(3), and for the reasons set forth 

above, EPA is proposing to approve ADEQ’s submittal dated March 

23, 2009 of the MAG Eight-Hour Ozone Redesignation Request and 

Maintenance Plan for the Maricopa Nonattainment Area (February 

2009) (“Eight-Hour Ozone Maintenance Plan”) as a revision to the 

Arizona state implementation plan (SIP). In connection with the 

 

36 See EPA memorandum dated October 31, 2013 entitled “Adequacy Documentation 

for Motor Vehicle Emission Budgets in the February 2009 Ozone Maintenance 

State Implementation Plan for the Phoenix-Mesa Nonattainment Area.”
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67 

Eight-Hour Ozone Maintenance Plan, EPA finds that the 

maintenance demonstration showing how the area will continue to 

attain the 1997 8-hour ozone NAAQS for 10 years beyond 

redesignation and the contingency provisions describing the 

actions that the relevant State, regional, and local agencies 

will take in the event of a future monitored violation meet all 

applicable requirements for maintenance plans and related 

contingency provisions in CAA section 175A. EPA is also 

proposing to approve the motor vehicle emissions budgets in the 

Eight-Hour Ozone Maintenance Plan because we find they meet the 

applicable transportation conformity requirements under 40 CFR 

93.118(e). The motor vehicle emissions budgets, 43.8 mtpd of VOC 

and 101.8 mtpd of NOx, include a 10% safety margin and correspond 

to the peak episode day (Thursday) during the June 2025 ozone 

episode that was used to model maintenance of the 1997 8-hour 

ozone NAAQS in the Phoenix-Mesa area in the Eight-Hour Ozone 

Maintenance Plan. 

Second, under CAA section 107(d)(3)(D), we are proposing to 

approve ADEQ’s request, which accompanied the submitted of the 

maintenance plan, to redesignate the Phoenix-Mesa 8-hour ozone 

nonattainment area to attainment for the 1997 8-hour ozone 

NAAQS. We are doing so based on our conclusion that the area has 

met the five criteria for redesignation under CAA section 

107(d)(3)(E). Our conclusion in this regard is in turn based on 
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our proposed determination that the area has attained the 1997 

8-hour ozone NAAQS, that relevant portions of the Arizona SIP 

are fully approved, that the improvement in air quality is due 

to permanent and enforceable reductions in emissions, that 

Arizona has met all requirements applicable to the Phoenix-Mesa 

8-hour ozone nonattainment area with respect to section 110 and 

part D of the CAA, and based on our proposed approval as part of 

this action of the Eight-Hour Ozone Maintenance Plan. 

EPA is soliciting public comments on the issues discussed 

in this document or on other relevant matters. We will accept 

comments from the public on this proposal for the next 30 days. 

We will consider these comments before taking final action. 

VII. Statutory and Executive Order Reviews 

Under the CAA, redesignation of an area to attainment and 

the accompanying approval of a maintenance plan under section 

107(d)(3)(E) are actions that affect the status of a 

geographical area and do not impose any additional regulatory 

requirements on sources beyond those imposed by State law. 

Redesignation to attainment does not in and of itself create any 

new requirements, but rather results in the applicability of 

requirements contained in the CAA for areas that have been 

redesignated to attainment. Moreover, the Administrator is 

required to approve a SIP submission that complies with the 

provisions of the Act and applicable Federal regulations. 42 
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U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP 

submissions, EPA’s role is to approve State choices, provided 

that they meet the criteria of the Clean Air Act. Accordingly, 

these actions merely propose to approve a State plan and 

redesignation request as meeting Federal requirements and do not 

impose additional requirements beyond those by State law. For 

these reasons, these proposed actions: 

· Are not a “significant regulatory action” subject to review 

by the Office of Management and Budget under Executive 

Order 12866 (58 FR 51735, October 4, 1993); 

· Do not impose an information collection burden under the 

provisions of the Paperwork Reduction Act (44 U.S.C. 3501 

et seq.); 

· Are certified as not having a significant economic impact 

on a substantial number of small entities under the 

Regulatory Flexibility Act (5 U.S.C. 601 et seq.); 

· Do not contain any unfunded mandate or significantly or 

uniquely affect small governments, as described in the 

Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4); 

· Do not have Federalism implications as specified in 

Executive Order 13132 (64 FR 43255, August 10, 1999); 

· Are not an economically significant regulatory action based 

on health or safety risks subject to Executive Order 13045 
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70 

(62 FR 19885, April 23, 1997); 

· Are not a significant regulatory action subject to 

Executive Order 13211 (66 FR 28355, May 22, 2001); 

· Are not subject to requirements of Section 12(d) of the 

National Technology Transfer and Advancement Act of 1995 

(15 U.S.C. 272 note) because application of those 

requirements would be inconsistent with the CAA; and 

· Do not provide EPA with the discretionary authority to 

address disproportionate human health or environmental 

effects with practical, appropriate, and legally 

permissible methods under Executive Order 12898 (59 FR 

7629, February 16, 1994). 

In addition, this proposed rule does not have Tribal 

implications as specified by Executive Order 13175 (65 FR 67249, 

November 9, 2000), because the SIP is not approved to apply in 

Indian country located in the State, and EPA notes that it will 

not impose substantial direct costs on Tribal governments or 

preempt Tribal law. Nonetheless, EPA has discussed the proposed 

action with the three Tribes, the Fort McDowell Yavapai Nation, 

the Salt River-Pima Maricopa Indian Community, and the Tohono 

O’odham Nation located within the Phoenix-Mesa 8-hour ozone 

nonattainment area. 

List of Subjects 

40 CFR Part 52 
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Environmental protection, Air pollution control, 

Intergovernmental relations, Nitrogen dioxide, Ozone, Reporting 

and recordkeeping requirements, Volatile organic compounds. 

40 CFR Part 81 

Environmental protection, Air pollution control, National 

parks, Wilderness areas. 

_March 14, 2014._______ _____________/s/___________ 

Dated: Jared Blumenfeld 

 Regional Administrator, 

Region IX.