Regional Administrator Jared Blumenfeld signed the following proposed rule on August 20, 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 Number EPA-R09-OAR-2014-0450.

6560-50-P

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

EPA-R09-OAR-2014-0450; FRLApproval and Promulgation of Implementation Plans; Arizona;

Nogales Nonattainment Area; Fine Particulate Matter Emissions

Inventories

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

SUMMARY: The Environmental Protection Agency (EPA) is proposing 

to approve revisions to the Arizona State Implementation Plan 

(SIP) concerning 2008 and 2010 emissions inventories for the 

2006 24-hour fine particle (PM2.5) National Ambient Air Quality 

Standard (NAAQS) for the Nogales PM2.5 nonattainment area. We are 

approving these annual emissions inventories under the Clean Air 

Act (CAA or the Act).

DATES: Any comments must arrive by [INSERT DATE 30 DAYS FROM THE 

DATE OF PUBLICATION IN THE FEDERAL REGISTER].

ADDRESSES: Submit comments, identified by docket number EPA-
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2

R09-OAR-2014-0450, by one of the following methods:

1. Federal eRulemaking Portal: www.regulations.gov. Follow 

the on-line instructions.

2. E-mail: wamsley.jerry@epa.gov.

3. Mail or deliver: Jerry Wamsley (Air-2), U.S. Environmental 

Protection Agency Region IX, 75 Hawthorne Street, San 

Francisco, CA 94105-3901. 

Instructions: All comments will be included in the public docket 

without change and may be made available online at 

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 www.regulations.gov or e-mail. 

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 you send e-mail 

directly to EPA, your e-mail address will be automatically 

captured and included as part of the public comment. If EPA 

cannot read your comment due to technical difficulties and 

cannot contact you for clarification, EPA may not be able to 

consider your comment. Electronic files should avoid the use of 
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3

special characters, any form of encryption, and be free of any 

defects or viruses.

Docket: Generally, documents in the docket for this action are 

available electronically at www.regulations.gov and in hard copy 

at EPA Region IX, 75 Hawthorne Street, San Francisco, California 

94105-3901. While all documents in the docket are listed at 

www.regulations.gov, some information may be publicly available 

only at the hard copy location (e.g., copyrighted material, 

large maps), and some may not be publicly available in either 

location (e.g., CBI). To inspect the hard copy materials, please 

schedule an appointment during normal business hours with the 

contact listed in the FOR FURTHER INFORMATION CONTACT section.

FOR FURTHER INFORMATION CONTACT: Jerry Wamsley, EPA Region IX, 

(415) 947-4111, wamsley.jerry@epa.gov. 

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

and “our” refer to EPA.

Table of Contents 

I. Background

A. PM2.5 NAAQS

B. Designation of PM2.5 Nonattainment Areas

C. Submittal Requirements for PM2.5 Nonattainment Areas

II. Procedural Requirements for SIP Revisions

A. Submittal for the Nogales Nonattainment Area

III. Analysis of Arizona’s Submittal

A. Nogales Area Emissions Inventories

IV. Proposed Action

V. Statutory and Executive Order Reviews

I. Background
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A. PM2.5 NAAQS

Under section 109 of the CAA, EPA establishes national 

ambient air quality standards (NAAQS or "standards") for 

certain pervasive air pollutants (referred to as "criteria 

pollutants") and conducts periodic reviews of the NAAQS to 

determine whether they should be revised or whether new NAAQS 

should be established.

On July 18, 1997, EPA revised the NAAQS for particulate 

matter to add new standards for fine particles, using PM2.5

(particles less than or equal to 2.5 micrometers in 

diameter) as the indicator for the pollutant. EPA 

established primary and secondary annual and 24-hour 

standards for PM2.5 (62 FR 38652).1 The annual standard was 

set at 15.0 micrograms per cubic meter (μg/m3), based on a 

3-year average of annual mean PM2.5 concentrations, and the 

24-hour standard was set at 65 μg/m3, based on the 3-year 

average of the 98th percentile of 24-hour PM2.5

concentrations at each population-oriented monitor within an 

area.

On October 17, 2006, EPA revised the level of the 24-hour 

 

1 For a given air pollutant, "primary" national ambient air quality standards 

are those determined by EPA as requisite to protect the public health, and 

"secondary" standards are those determined by EPA as requisite to protect the 

public welfare from any known or anticipated adverse effects associated with 

the presence of such air pollutant in the ambient air. See CAA section 109(b).
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5

PM2.5 NAAQS to 35 μg/m3, based on a 3-year average of the 98th 

percentile of 24-hour concentrations (71 FR 61144). In this 

same action, EPA also retained the 1997 annual PM2.5 standard at 

15.0 μg/m3 based on a 3-year average of annual mean PM2.5

concentrations, but with tighter constraints on the spatial 

averaging criteria.

B. Designation of PM2.5 Nonattainment Areas

Effective December 14, 2009, EPA established the initial 

air quality designations for most areas in the United States for 

the 2006 24-hour PM2.5 NAAQS (74 FR 58688, November 13, 2009). 

Among the various areas designated in 2009, EPA designated the 

Nogales area in Arizona as nonattainment for the 2006 24-hour 

PM2.5 NAAQS.2 The boundaries for this area are described in 40 CFR 

81.303.

C. Submittal Requirements for PM2.5 Nonattainment Areas

Section 172(c)(3) of the CAA requires a state with an area 

designated as nonattainment of a standard to submit a 

comprehensive, accurate, and current inventory of actual 

emissions for the nonattainment area for EPA’s review and 

approval. EPA’s requirements for an emissions inventory for the 

 

2 The Nogales PM2.5 nonattainment area covers 76.1 square miles and is located 

in southern Santa Cruz County, Arizona adjacent to the international border 

with Mexico.
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PM2.5 NAAQS are set forth in 40 CFR 51.1008.3,4 As applied to the 

2006 PM2.5 24-hour NAAQS, this proposal is limited to the

emissions inventories for directly emitted PM2.5 and PM2.5 

precursors submitted by the Arizona Department of Environmental 

Quality (ADEQ) for the Nogales nonattainment area, as required 

under section 172(c)(3) of the CAA. 

On January 7, 2013, EPA finalized a determination that the 

Nogales nonattainment area had attained the 2006 24-hour PM2.5

NAAQS (78 FR 887). This determination of attainment was based 

upon complete, quality-assured, and certified ambient air 

monitoring data showing that the Nogales nonattainment area had 

monitored attainment of the 2006 24-hour PM2.5 NAAQS over three 

years, from 2009 to 2011. Based on this determination, the 

requirements for Arizona to submit an attainment demonstration, 

reasonably available control measures, a reasonable further 

 

3 40 CFR 51.1008 (a)(2) and (b) do not apply for the Nogales area because they 

relate to requirements for attainment demonstrations and reasonable further 

progress (RFP); these requirements were suspended for the Nogales PM2.5 

nonattainment area so long as the area continues to meet the PM2.5 standard. 

For further discussion of our Clean Data Policy as applied to the Nogales 

area, refer to our proposed rule (77 FR 65656, October 30, 2012) and final 

rule (78 FR 887, January 7, 2013).

4 Although the U.S. Court of Appeals for the District of Columbia (DC Circuit) 

recently remanded this rule and directed EPA to re-promulgate it pursuant to 

subpart 4 of part D, title I of the CAA (see Natural Resources Defense 

Council v. EPA, 706 F.3d 428 (D.C. Cir. 2013)), the court’s ruling in this 

case does not affect EPA’s action on these emissions inventories. Subpart 4 

of part D, title I of the Act contains no specific provision governing 

emissions inventories for PM10 or PM2.5 nonattainment areas that supersedes the 

general emissions inventory requirement for all nonattainment areas in CAA 

section 172(c)(3). See “State Implementation Plans; General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990,” 57 FR 

13498, (April 16, 1992).
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7

progress (RFP) plan, and contingency measures for failure to 

meet RFP and attainment deadlines were suspended for so long as 

the Nogales area continues to attain the 2006 24-hour PM2.5

NAAQS. The emissions inventory submittal requirement in CAA 

section 172(c)(3), however, is not suspended by our 

determination of attainment. Consequently, Arizona has submitted 

the Nogales area emissions inventories to address the 172(c)(3) 

requirement. Please see our October 30, 2012 proposed rule for 

further discussion of EPA’s Clean Data Policy and its 

application to the Nogales nonattainment area (77 FR 65656). 

II. Procedural Requirements for SIP Revisions

Sections 110(a)(1) and 110(l) of the Act require states to 

provide reasonable notice and public hearing prior to adoption 

of SIP revisions. Section 110(k)(1)(B) requires EPA to 

determine whether a SIP submittal is complete within 60 days of 

receipt, but no later than 6 months after the date of the 

submittal. Any state submittal that we have not determined to be 

complete or incomplete will become complete by operation of law

six months after the day of submittal. A finding of completeness 

does not approve the submittal as part of the SIP and it does

not indicate that the submittal is approvable. A completeness 

finding starts a twelve month clock for EPA to act on the SIP 

submittal. See CAA section 110(k)(2). 
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A. Submittal for the Nogales Nonattainment Area

On September 6, 2013, Arizona submitted the 2008 and 2010 

PM2.5 emissions inventories for the Nogales nonattainment area

titled “Arizona State Implementation Plan Revision for the 

Nogales PM2.5 Nonattainment Area”.5 Arizona’s submittal provides 

documentation of the public review process followed by the State 

prior to submitting the emissions inventories to EPA. The 

documentation provides evidence that reasonable notice of a 

public hearing was provided to the public and that a public 

hearing was conducted prior to submittal.6 Arizona’s submittal of 

the Nogales nonattainment area emissions inventories became 

complete by operation of law on March 6, 2014.

Based on the documentation provided in Arizona’s SIP 

revision submittal, we find that the Nogales area emissions

inventories satisfies the procedural requirements of sections

110(a)(1) and 110(l) of the Act for revising SIPs. 

III. Analysis of Arizona’s Submittal

 

5 See letter from Eric Massey, Director, Air Quality Division, ADEQ to Jared 

Blumenfeld, Regional Administrator, USEPA, dated September 6, 2013 and 

enclosure titled “Arizona State Implementation Plan Revision for the Nogales 

PM2.5 Nonattainment Area”. Included within Appendix A of this document is 

“Primary PM2.5 and Secondary Precursor Emissions Inventories for 2008 and 

2010,” July 26, 2013, Arizona Department of Environmental Quality (ADEQ), 

hereafter referred to as Appendix A. Because much of the detailed emissions 

inventory information and analyses for the submittal document are located 

within Appendix A, this document is the substantive focus of this proposal.

6 A public hearing was conducted on September 3, 2013 after 30 days prior 

notice. See Enclosure 4 of the submittal for public notice documentation and 

public hearing transcripts. 
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Section 172(c)(3) of the CAA requires states to submit a 

comprehensive, accurate, and current inventory of actual 

emissions for each nonattainment area. EPA’s requirements for an 

emissions inventory for the PM2.5 NAAQS are set forth in 40 CFR 

51.1008. For the PM2.5 NAAQS, the pollutants to be inventoried are

PM2.5 and PM2.5 precursors (i.e., nitrogen oxides (NOx), volatile 

organic compounds (VOCs), sulfur dioxide (SO2), and ammonia 

(NH3)).7

A. Nogales Area Emissions Inventories

Arizona’s submitted Nogales area emissions inventories

provide annual 2008 and 2010 emissions estimates (tons per year)

for PM2.5 and PM2.5 precursors (i.e., NOx, VOCs, SO2, and

NH3). The source categories include non-road mobile sources, nonpoint sources, on-road mobile sources, and point or stationary 

sources. A summary of the Nogales area emissions inventories are 

provided below in Tables 1 and 2. The detailed Nogales emissions

inventories are found in Appendix A of Arizona’s submittal. 

Table 1, 2008 Nogales Nonattainment Area Emissions Inventories 

(tons per year)

Source Category PM2.5 VOC NOx SO2 NH3

Non-Road Mobile 13.1 158.6 142.7 2.8 0.1

Non-Point 396.0 902.7 48.8 28.3 22.9

 

7 Emissions Inventory Guidance for Implementation of Ozone and Particulate 

Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze 

Regulations, EPA-454/R-05-001, August 2005, updated November 2005. 

http://www.epa.gov/ttn/chief/eidocs/eiguid/eiguidfinal_nov2005.pdf.
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On-Road Mobile 25.1 426.2 912.9 7.5 14.4

Point/Stationary 1.4 3.3 11.0 0.5 0

TOTALS 435.6 1490.8 1115.4 39.1 37.4

Entries are rounded consistent with submittal, as such, totals

may vary due to rounding. Source: Appendix A, Table 6.1.

Table 2, 2010 Nogales Nonattainment Area Emissions Inventories 

(tons per year)

Source Category PM2.5 VOC NOx SO2 NH3

Non-Road Mobile 13.1 159.6 142.7 2.8 0.1

Non-Point 399.2 912.6 49.3 28.3 23.0

On-Road Mobile 20.1 369.5 743.7 4.6 13.0

Point/Stationary 1.4 3.3 11.0 0.5 0

TOTALS 433.9 1445.0 946.8 36.2 36.1

Entries are rounded consistent with submittal, as such, totals 

may vary due to rounding. Source: Appendix A, Table 6.1.

The Nogales area primary PM2.5 and secondary precursor 

emissions inventories for 2008 and 2010 include emissions

estimates from non-road mobile, non-point, on-road mobile 

sources, and point or stationary sources. ADEQ derived these 

emissions inventories for 2008 and 2010 from emissions data for 

Santa Cruz County, Arizona, in EPA’s 2008 National Emissions

Inventory (NEI) versions 1.5 and 2.0. See Appendix A, section 3. 

Using 2008 NEI county-level emissions estimates, ADEQ allocated 

the share of nonattainment area emissions from county level 

estimates by one of three characteristics and relative 

percentages: (1) human-induced activities/source categories were 
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allocated by nonattainment area population share, 66.1 percent; 

(2) location-based activities/source categories were allocated 

by nonattainment area share of land area, 6.15 percent; and, (3) 

location specific sources, such as point sources, were fully 

allocated to the nonattainment area, as applicable. See Appendix 

A, Table 3.1 for population and land area allocation ratios; 

and, see Appendix A, section 2 for their derivation. In the case 

of on-road mobile source emissions, ADEQ estimated Santa Cruz 

County emissions separately from the NEI data using EPA’s onroad emissions factor model MOVES2010b and then allocated

county-level emissions to the Nogales area by population share. 

ADEQ developed 2010 emissions inventory estimates for the 

Nogales nonattainment area from 2008 levels by applying a 2008 

to 2010 population-based growth rate of 1.1 percent, relative 

activity levels, or held emissions estimates constant, as 

applicable. See Appendix A, section 3.4 for ADEQ’s 2010 

emissions inventories discussion. 

In sum, we find this methodology reasonable and based on 

reliable estimates of population and land area. We concur with 

the overall methodology, basis for allocating emissions and 

allocation calculations used to produce the Nogales emissions 

inventories for PM2.5 and the precursor pollutants. ADEQ’s 

population estimates are Arizona Department of Administration 
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estimates that have been reconciled with U.S. Census figures. 

We have verified the land area allocation ratio using 

geographical information system applications. Please see our 

Technical Support Document (TSD) for our detailed review and 

discussion of Arizona’s emissions inventories methodology and 

results.

In our review, we compared the ADEQ estimates for PM2.5 and 

the precursor pollutants with the subsequent and final release of 

the 2008 NEI version 3.0. The 2011 NEI version 1.0 was released 

on September 30, 2013 and was not available for use by ADEQ. We 

expected to find nominal differences between the NEI versions 

(1.5 and 2.0) used by ADEQ and the final version (3.0) of the NEI 

based on corrections and re-estimates from one version to the 

next. EPA released the 2008 NEI version 3.0 in March 2013 prior 

to Arizona’s submittal of the Nogales emissions inventories in 

September 2013. While we did not require ADEQ to use the 2008 NEI 

version 3.0 given their emissions inventories were already 

drafted, we reviewed the submittal against 2008 NEI version 3.0 

to ensure that any subsequent version 3.0 corrections or updates 

are nominal changes to the submitted emissions inventories.

We found that the submitted PM2.5, NH3, NOx, and SO2 emissions

inventories, four of five emissions inventories, show little or

no variance from the 2008 NEI version 3.0 emissions inventory, 
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our comparison data base. The submitted VOC emissions inventory 

shows a small under-reporting of 3 - 10 percent when compared 

either across the Santa Cruz County 2008 NEI version 3.0 baseline 

emissions estimates, or to the submitted Nogales area emissions 

estimates. This small overall underestimate of VOC emissions is 

not significant, and becomes less significant when considered 

against an adjusted increase provided by the submitted VOC onroad mobile emissions inventory compared to the reference 2008 

NEI on-road mobile VOC emissions estimates. In this way, we 

consider the adjusted difference in the submitted overall VOC 

emission inventory and our reference 2008 NEI version 3.0 VOC 

emissions inventory to be closer to 3 percent rather than 10 

percent, a small variance in the context of the overall PM2.5

emissions inventories. For our detailed review, please see our 

TSD within the docket of this rulemaking.

In conclusion, EPA has reviewed the results, procedures,

and methodologies Arizona used to produce the 2008 and 2010 

Nogales area PM2.5 and PM2.5 precursor emissions inventories and

finds that these emissions inventories meet the requirements of 

the CAA and EPA guidance. Consequently, we propose to approve the 

submitted PM2.5, NH3, NOx, SO2, and VOC emissions inventories as 

meeting the CAA’s section 172(c)(3) requirement to provide a 

comprehensive, accurate, and current inventory of actual 
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emissions for the Nogales nonattainment area.8

IV. Proposed Action

EPA is proposing to approve the 2008 and 2010 Nogales 

nonattainment area PM2.5 and PM2.5 precursor emissions inventories 

submitted by Arizona on September 6, 2013. In doing so, EPA has 

determined that Arizona’s submittal is consistent with sections

110 and 172(c)(3)of the CAA. 

V. Statutory and Executive Order Reviews 

Under the Clean Air Act, the Administrator is required to 

approve a SIP submission that complies with the provisions of 

the Act and applicable Federal regulations. 42 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, this action merely 

approves State law as meeting Federal requirements and does not 

impose additional requirements beyond those imposed by State 

law. For that reason, this action:

• is 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);

 

8 Please note that our review and proposed approval of Arizona’s PM2.5

emissions inventories for the Nogales nonattainment area, their data sources, 

and methodologies are specific to this submittal and may not be applicable to 

all PM2.5 nonattainment areas and the related PM2.5 and precursor emissions 

inventories.
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• does not impose an information collection burden under the 

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

et seq.);

• is 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.);

• does not contain any unfunded mandate or significantly or 

uniquely affect small governments, as described in the 

Unfunded Mandates Reform Act of 1995 (Public Law 104-4);

• does not have Federalism implications as specified in 

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

• is not an economically significant regulatory action based 

on health or safety risks subject to Executive Order 13045 

(62 FR 19885, April 23, 1997);

• is not a significant regulatory action subject to Executive 

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

• is 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 Clean Air Act; 

and

• does not provide EPA with the discretionary authority to 

address disproportionate human health or environmental 
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effects with practical, appropriate, and legally 

permissible methods under Executive Order 12898 (59 FR 

7629, February 16, 1994). 

In addition, this action 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.

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, 

Incorporation by reference, Intergovernmental relations, 

Nitrogen dioxide, Particulate matter, Reporting and 

recordkeeping requirements, Sulfur oxides, Ammonia, Volatile 

organic compounds.

___ _______________ ___________________________ 

Dated Jared Blumenfeld,

Regional Administrator,

Region IX.