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(5) Durum wheat, Soft Red Winter 

wheat, and Unclassed wheat in the class 

Hard White wheat. 

* * * * * 

3. Amend § 810.2204 by revising 

paragraph (a) to read as follows: 

§ 810.2204 Grades and grade requirements 

for wheat. 

(a) Grades and grade requirements for 

all classes of wheat, except Mixed 

wheat. 

GRADES AND GRADE REQUIREMENTS

Grading factors 

Grades U.S. Nos. 

1 2 3 4 5 

Minimum pound limits of 

Test weight per bushel: 

Hard Red Spring wheat or White Club wheat .................................. 58.0 57.0 55.0 53.0 50.0 

All other classes and subclasses ..................................................... 60.0 58.0 56.0 54.0 51.0 

Maximum percent limits of 

Defects: 

Damaged kernels 

Heat (part of total) ..................................................................... 0.2 0.2 0.5 1.0 3.0 

Total ........................................................................................... 2.0 4.0 7.0 10.0 15.0 

Foreign material ....................................................................................... 0.4 0.7 1.3 3.0 5.0 

Shrunken and broken kernels .................................................................. 2.0 4.0 8.0 12.0 20.0 

Total 1 ....................................................................................................... 3.0 5.0 8.0 12.0 20.0 

Wheat of other classes 2 .......................................................................... 1.0 2.0 3.0 10.0 10.0 

Contrasting classes ................................................................................. 3.0 5.0 10.0 10.0 10.0 

Total 3 ....................................................................................................... 0.1 0.1 0.1 0.1 0.1 

Stones 

Maximum count limits of 

Other material in one kilogram: 

Animal filth ........................................................................................ 1 1 1 1 1 

Castor beans .................................................................................... 1 1 1 1 1 

Crotalaria seeds ................................................................................ 2 2 2 2 2 

Glass ................................................................................................. 0 0 0 0 0 

Stones ............................................................................................... 3 3 3 3 3 

Unknown foreign substances ........................................................... 3 3 3 3 3 

Total 4 ................................................................................................ 4 4 4 4 4 

Insect-damaged kernels in 100 grams ............................................. 31 31 31 31 31 

U.S. Sample grade is Wheat that: 

(a) Does not meet the requirements for U.S. Nos. 1, 2, 3, 4, or 5; or 

(b) Has a musty, sour, or commercially objectionable foreign odor (except smut or garlic odor) or 

(c) Is heating or of distinctly low quality. 

1 Includes damaged kernels (total), foreign material, shrunken and broken kernels. 

2 Unclassed wheat of any grade may contain not more than 10.0 percent of wheat of other classes. 

3 Includes contrasting classes. 

4 Includes any combination of animal filth, castor beans, crotalaria seeds, glass, stones, or unknown foreign substance. 

* * * * * 

Alan R. Christian, 

Acting Administrator, Grain Inspection, 

Packers and Stockyards Administration. 

[FR Doc. 2012–8663 Filed 4–10–12; 8:45 am] 

BILLING CODE 3410–KD–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R09–OAR–2012–0253; FRL–9658–6] 

Approval and Promulgation of Air 

Quality Implementation Plan for 1997 

8-Hour Ozone Standard; Arizona 

AGENCY: U.S. Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: EPA is proposing to approve 

revisions to the Arizona state 

implementation plan (SIP) that 

demonstrate attainment of the 1997 

8-hour ozone national ambient air 

quality standards in the Phoenix-Mesa 

nonattainment area by June 15, 2009. 

These SIP revisions are the 2007 Ozone 

Plan developed by the Maricopa 

Association of Governments and 

adopted and submitted to EPA by the 

Arizona Department of Environmental 

Quality on June 13, 2007. EPA is 

proposing to approve the 2007 Ozone 

Plan based on our determination that 

the plan contains all the provisions 

required for areas classified as 

nonattainment under Part D, Subpart 1 

of the Clean Air Act, including the 

demonstration of reasonably available 

control measures (RACM), reasonable 

further progress (RFP), emission 

inventories, transportation conformity 

motor vehicle emission budgets for 

2008, and contingency measures to be 


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Federal Register / Vol. 77, No. 70 / Wednesday, April 11, 2012 / Proposed Rules 21691 

1 In March 2008, EPA completed another review 

of the primary and secondary ozone standards and 

further tightened the standards by lowering the 

level for both to 0.075 ppm (73 FR 16436, Mar. 27, 

2008). 

implemented if the Phoenix-Mesa 

nonattainment area fails to attain by 

June 15, 2009. 

DATES: Written comments must be 

received on or before May 11, 2012. 

ADDRESSES: Submit comments, 

identified by docket number EPA–R09– 

OAR–2012–0253, by one of the 

following methods: 

• Federal e-Rulemaking Portal: 

www.regulations.gov. Follow the online instructions. 

• Email: lee.anita@epa.gov. 

• Mail or deliver: Marty Robin, Office 

of Air Planning (AIR–2), U.S. 

Environmental Protection Agency 

Region IX, 75 Hawthorne Street, San 

Francisco, CA 94105. 

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 email. The 

www.regulations.gov Web site 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 

email directly to EPA, your email 

address will be automatically captured 

and included as part of the public 

comment. If EPA cannot read your 

comments due to technical difficulties 

and cannot contact you for clarification, 

EPA may not be able to consider your 

comment. 

Docket: The index to the docket for 

this action is available electronically on 

the www.regulations.gov Web site and 

in hard copy at EPA Region IX, 75 

Hawthorne Street, San Francisco, 

California 94105. While all documents 

in the docket are listed in the index, 

some documents may be publicly 

available only at the hard copy location 

(e.g., copyrighted material), and some 

may not be publicly available at 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 

below. Copies of the SIP materials are 

also available for inspection at the 

following location: 

• Arizona Department of 

Environmental Quality, 1110 W. 

Washington Street, First Floor, Phoenix, 

AZ 85007, Phone: (602) 771–2217. 

The SIP materials are also 

electronically available at: http:// 

www.azmag.gov/Projects/ 

Project.asp?CMSID2=1120. 

FOR FURTHER INFORMATION CONTACT: 

Anita Lee, Air Planning Office (AIR–2), 

U.S. Environmental Protection Agency, 

Region IX, (415) 972–3958, 

lee.anita@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. The 1997 8-Hour Ozone Standard and the 

Phoenix-Mesa Ozone Nonattainment 

Area 

A. Background on the 1997 8-Hour Ozone 

NAAQS 

B. The Phoenix-Mesa 8-Hour Ozone 

Nonattainment Area 

II. CAA and Regulatory Requirements for 

1997 8-Hour Ozone Nonattainment Area 

SIPs 

III. Arizona’s State Implementation Plan 

Submittal To Address Ozone Attainment 

in the Phoenix-Mesa Nonattainment 

Area 

A. Arizona’s SIP Submittal 

B. CAA Procedural and Administrative 

Requirements for SIP Submittals 

IV. Review of the 2007 Ozone Plan for 

Phoenix-Mesa 

A. Emission Inventories 

B. Reasonably Available Control Measures 

Demonstration and Control Strategy 

C. Attainment Demonstration 

D. Reasonable Further Progress 

Demonstration 

E. Contingency Measures 

F. Motor Vehicle Emissions Budgets for 

Transportation Conformity 

V. EPA’s Proposed Action 

VI. Statutory and Executive Order Reviews 

Throughout this document, ‘‘we’’, 

‘‘us’’ and ‘‘our’’ refer to EPA. 

I. The 1997 8-Hour Ozone Standard and 

the Phoenix-Mesa Ozone 

Nonattainment Area 

A. Background on the 1997 8-Hour 

Ozone NAAQS 

Ground-level ozone pollution is 

formed in the atmosphere from the 

reaction of 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- and offroad motor vehicles and engines, power 

plants and industrial facilities, and 

smaller area sources such as lawn and 

garden equipment and paints. 

Scientific evidence indicates that 

adverse public health effects occur 

following exposure to ozone, 

particularly in children and adults with 

lung disease. Breathing air containing 

ozone can reduce lung function and 

inflame airways, which can increase 

respiratory symptoms and aggravate 

asthma or other lung diseases. Ozone 

exposure also has been associated with 

increased susceptibility to respiratory 

infections, medication use, doctor visits, 

and emergency department visits and 

hospital admissions for individuals with 

lung disease. Ozone exposure also 

increases the risk of premature death 

from heart or lung disease. Children are 

at increased risk from exposure to ozone 

because their lungs are still developing 

and they are more likely to be active 

outdoors, which increases exposure. See 

‘‘Fact Sheet, Proposal to Revise the 

National Ambient Air Quality Standards 

for Ozone’’, January 6, 2010 and 75 FR 

2938 (January 19, 2010). 

On July 18, 1997, EPA revised the 

primary and secondary national ambient 

air quality standards (NAAQS or 

standard) for ozone to replace the 

existing 1-hour ozone standard of 0.12 

parts per million (ppm) with an 8-hour 

standard of 0.08 ppm 1 (62 FR 33856). 

EPA revised the ozone standard after 

considering substantial evidence from 

numerous health studies demonstrating 

that serious health effects are associated 

with exposures to ozone concentrations 

above the levels of these revised 

standards. 

B. The Phoenix-Mesa 8-Hour Ozone 

Nonattainment Area 

Following promulgation of a new or 

revised NAAQS, EPA is required by 

Clean Air Act (CAA) section 107(d) to 

designate areas throughout the nation as 

attaining or not attaining the NAAQS. 

Under the implementation rule for the 

1997 8-hour ozone standard, EPA 

designated certain areas as 

nonattainment under title I, part D, 

subpart 1 of the CAA (subpart 1) if the 

area’s 1-hour ozone design value was 

above the level of the standard but 

below 0.121 ppm. On April 15, 2004, 

EPA designated Phoenix-Mesa as 

‘‘Subpart 1’’ nonattainment for the 1997 

8-hour ozone standard under CAA 

section 172. See 69 FR 23858 (April 30, 

2004) and 40 CFR 81.303. The 

designation became effective on June 15, 

2004. 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. 

Arizona Department of Environmental 

Quality (ADEQ) submitted the 2007 

Attainment Plan to EPA on June 13, 


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2Letter from Stephen A. Owens, Director, 

Arizona Department of Environmental Quality to 

Wayne Nastri, Regional Administrator, U.S. 

Environmental Protection Agency, Region IX, dated 

June 13, 2007, plus three enclosures, including the 

‘‘Eight-Hour Ozone Plan for the Maricopa 

Nonattainment Area, dated June 2007’’ and 

Appendices Volumes one and two, dated June 2007. 

3On March 23, 2009, ADEQ submitted to EPA a 

redesignation request and maintenance plan for 

Phoenix-Mesa for the 1997 8-hour ozone standard 

based on ambient ozone monitoring data for the 

2006–2008 period. EPA has not yet acted on this 

submittal. The maintenance plan and redesignation 

request are available from the Maricopa Association 

of Governments at: http://www.azmag.gov/Projects/ 

Project.asp?CMSID2=1120&MID=Environmental

%20Programs. 

4A design value is an ambient concentration 

calculated using a specific methodology to evaluate 

monitored air quality data and is used to determine 

whether an area’s air quality meets a NAAQS. The 

methodology for calculating design values for the 8- 

hour ozone NAAQS is found in 40 CFR part 50, 

Appendix I. 

5Based on the rounding conventions described in 

40 CFR part 50, Appendix I, a design value of 0.085 

ppm is the lowest value that exceeds the 1997 8- 

hour ozone NAAQS of 0.08 ppm. 

6EPA now refers to these areas as ‘‘former subpart 

1’’ nonattainment areas in light of the SCAQMD 

decision. 

7EPA is currently obligated under the terms of a 

Consent Decree to take final action on the 2007 

Ozone Plan by May 31, 2012. See WildEarth 

Guardians v. Jackson, Case No. 4:11–cv–02205–SI 

(N.D. CA). 

8Although the DC Circuit Court in SCAQMD 

rejected EPA’s rationale for implementing the 1997 

8-hour ozone standard in certain nonattainment 

areas solely under subpart 1, EPA does not believe 

that the Court’s ruling in this case alters any subpart 

1 requirements that currently apply to the 2007 

Ozone Plan. 

9EPA has revised or proposed to revise several 

elements of the 8-hour ozone implementation rule 

since its initial promulgation in 2004. See, e.g., 74 

FR 2936 (January 16, 2009); 75 FR 51960 (August 

24, 2010); and 75 FR 80420 (December 22, 2010). 

None of these revisions affect any provision of the 

rule that is applicable to our proposed action today 

on the Phoenix-Mesa 2007 8-hour Ozone SIP. 

2007 2 to attain the 1997 8-hour ozone 

standard by the attainment date of June 

15, 2009, which is 5 years after the 

effective date of the area’s designation 

as nonattainment.3

In June 2007, the United States Court 

of Appeals for the District of Columbia 

Circuit (D.C. Circuit Court) vacated the 

portion of the 2004 ozone 

implementation rule that allowed areas 

to be classified under subpart 1. See 

South Coast Air Quality Mgmt. Dist. v. 

EPA, 472 F. 3d 882 (D.C. Cir. 2006), 

reh’g denied 489 F.3d 1245 (SCAQMD) 

(vacating certain elements of EPA’s 

Phase 1 ozone implementation rule). On 

January 16, 2009 (74 FR 2936), EPA 

published a proposed rule to address, 

among other issues, the DC Circuit 

Court vacatur of the classification 

system that EPA used to designate a 

subset of initial 1997 8-hour ozone 

nonattainment areas under subpart 1. In 

that rulemaking, EPA proposed that all 

areas designated nonattainment for the 

1997 8-hour ozone NAAQS under 

subpart 1 would be classified as subpart 

2 areas (hereafter referred to as the 

Subpart 1/Subpart 2 Rulemaking). The 

Phoenix-Mesa area is included in the 

areas that would be classified under 

subpart 2 if EPA’s proposal is finalized. 

EPA has not yet taken final action on 

the Subpart 1/Subpart 2 Rulemaking. 

Following completion of the Subpart 1/ 

Subpart 2 Rulemaking, EPA will address 

in a future rulemaking any additional 

requirements that become applicable to 

Phoenix-Mesa, if any, as a result of its 

classification under subpart 2. If, after 

Phoenix-Mesa is classified under 

subpart 2, EPA determines in a future 

rulemaking that the area is in attainment 

with the 1997 8-hour ozone standard, 

then the obligation to submit certain 

planning SIPs related to attainment of 

the 1997 8-hour ozone standard 

pursuant to its subpart 2 classification 

would be suspended in accordance with 

40 CFR 51.918. 

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, the Fort 

McDowell Yavapai Nation and the Salt 

River-Pima Maricopa Indian 

Community. For a precise description of 

the geographic boundaries of the 

Phoenix-Mesa nonattainment area, see 

40 CFR 81.303. The Maricopa 

Association of Governments (MAG) is 

the agency with primary responsibility 

for developing the plan to attain the 

1997 8-hour ozone standard for 

Phoenix-Mesa. 

Ambient 8-hour ozone concentrations 

in Phoenix-Mesa vary depending on 

location and season, with the highest 

values generally occurring in May– 

September, in north Phoenix or the air 

quality monitors located in the 

mountainous northeastern region of the 

Phoenix-Mesa nonattainment area. 

Ozone design values 4 from PhoenixMesa that exceeded the 1997 8-hour 

standard of 0.08 parts per million 5

(ppm) ranged from 0.085 ppm (for the 

2000–2002, 2001–2003, and 2003–2005 

periods) to 0.088 ppm (for the 1998– 

2000 and 1999–2001 periods). The 

ozone design values for the PhoenixMesa nonattainment area for the 2004– 

2006 period (highest design value was 

0.083 ppm) and years thereafter were at 

or below the standard. See EPA Air 

Quality System (AQS) data available in 

the docket for this proposed rulemaking 

and Table 3 below. 

II. CAA and Regulatory Requirements 

for 1997 8-Hour Ozone Nonattainment 

Area SIPs 

Each area designated nonattainment 

for the 1997 8-hour ozone standard is 

subject to, at minimum, the general 

requirements for nonattainment area 

plans in subpart 1 of part D, title I of the 

CAA. Subpart 2 of part D contains more 

detailed requirements for ozone 

nonattainment areas classified under 

this subpart. The Phoenix-Mesa ozone 

nonattainment area is not currently 

classified under subpart 2.6 EPA has 

proposed to classify the Phoenix-Mesa 

area under subpart 2 as ‘‘marginal’’ 

nonattainment for the 1997 8-hour 

ozone NAAQS (see 74 FR 2936 at 2944, 

January 16, 2009) but has not yet 

completed this rulemaking. Although a 

future final decision by EPA to classify 

the Phoenix-Mesa area under subpart 2 

may trigger additional future 

requirements for the area, EPA believes 

that this does not prevent EPA from 

proposing or ultimately finalizing our 

action on the 2007 Ozone Plan in 

accordance with the subpart 1 

requirements that currently apply to the 

area.7 Thus, for purposes of evaluating 

the 2007 Ozone Plan, we are reviewing 

it for consistency with the applicable 

requirements of part D, title I of the Act, 

which are contained in sections 

172(c)(1)–(9).8

In order to assist states in developing 

effective plans to attain the ozone 

standard, EPA issued the 8-hour ozone 

implementation rule. This rule was 

finalized in two phases. The first phase 

of the rule addresses classifications for 

the 1997 8-hour ozone standard, 

applicable attainment dates for the 

various classifications, and the timing of 

emissions reductions needed for 

attainment. See 69 FR 23951 (April 30, 

2004). The second phase addresses SIP 

submittal dates and the requirements for 

reasonably available control technology 

and measures (RACT and RACM), 

reasonable further progress (RFP) 

demonstration, modeling and 

attainment demonstrations, contingency 

measures, and new source review. See 

70 FR 71612 (November 29, 2005). The 

rule is codified at 40 CFR part 51, 

subpart X.9 We discuss each of the 

applicable CAA and regulatory 

requirements for 8-hour ozone 

nonattainment plans in more detail 

below. 

III. Arizona’s State Implementation 

Plan Submittal To Address Ozone 

Attainment in the Phoenix-Mesa 

Nonattainment Area 

A. Arizona’s SIP Submittal 

On June 13, 2007, the Arizona 

Department of Environmental Quality 

(ADEQ) submitted the ‘‘Eight-Hour 


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10Letter from Stephen A. Owens, Director of 

Arizona Department of Environmental Quality, to 

Wayne Nastri, Regional Administrator, U.S. 

Environmental Protection Agency, Region IX, 

‘‘Submittal of the Eight-Hour Ozone Plan for the 

Maricopa County Nonattainment Area’’. June 13, 

2007. 

11 ‘‘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, November 2005. This document is available at: 

http://www.epa.gov/ttnchie1/eidocs/eiguid/ 

index.html. 

12By ‘‘future year baseline inventories’’ or 

‘‘projected baseline inventories’’, we mean 

projected emission inventories for future years that 

account for, among other things, the ongoing effects 

of economic growth and adopted emission control 

requirements. 

13EPA’s ozone implementation rule defines 

‘‘attainment year ozone season’’ as ‘‘the ozone 

season immediately preceding a nonattainment 

area’s attainment date.’’ 40 CFR 51.900(g). Because 

the attainment date for Phoenix-Mesa is June 15, 

2009, we refer to 2008 as the attainment year, and 

the 2008 ozone season as the ‘‘attainment year 

ozone season.’’ 

Ozone Plan for the Maricopa 

Nonattainment Area’’ (2007 Ozone Plan) 

to EPA as a revision to the Arizona SIP. 

The plan was deemed complete by 

operation of law on December 13, 2007. 

MAG developed the 2007 Ozone Plan 

and the MAG Regional Council 

Executive Committee adopted the plan 

on June 11, 2007. ADEQ adopted the 

plan on June 13, 2007.10 The 2007 

Ozone Plan contains complete emission 

inventories for ozone precursors for 

2002 and 2008, photochemical 

modeling to demonstrate that the 

standard will be attained in 2008 

through the continued implementation 

of federal, state, and local control 

measures, motor vehicle emission 

budgets (MVEBs) used for transportation 

conformity, and descriptions of the 

State’s compliance with CAA 

requirements for ‘‘Subpart 1’’ ozone 

nonattainment areas. We are proposing 

to approve the 2007 Ozone Plan for the 

Phoenix-Mesa nonattainment area. 

B. CAA Procedural and Administrative 

Requirements for SIP Submittals 

CAA sections 110(a)(1) and (2) and 

110(l) require a state to provide 

reasonable public notice and 

opportunity for public hearing prior to 

the adoption and submittal of a SIP or 

SIP revision. To meet this requirement, 

every SIP submittal should include 

evidence that adequate public notice 

was given and an opportunity for a 

public hearing was provided consistent 

with EPA’s implementing regulations in 

40 CFR 51.102. 

MAG has satisfied the applicable 

statutory and regulatory requirements 

for reasonable public notice and hearing 

prior to adoption and submittal of the 

2007 Ozone Plan. MAG and ADEQ 

jointly held two public hearings on June 

1, 2007 and June 4, 2007. As evidence 

of notification of public hearings 

consistent with 40 CFR 51.102, the SIP 

submittal includes proof of newspaper 

publication and copies of letters sent to 

EPA and affected federal, state, and 

local agencies notifying interested 

parties of the joint MAG and ADEQ 

public hearings. We find, therefore, that 

the 2007 Ozone Plan submittal meets 

the procedural requirements for public 

notice and hearing in sections 110(a) 

and 110(l) of the CAA. 

CAA section 110(k)(1)(B) requires 

EPA to determine whether a SIP 

submittal is complete within 60 days of 

receipt. This section also provides that 

any plan submittal that EPA has not 

affirmatively determined to be complete 

or incomplete will be deemed complete 

by operation of law six months after the 

date of submittal. EPA’s SIP 

completeness criteria are found in 40 

CFR part 51, Appendix V. The 2007 

Ozone Plan, submitted by ADEQ on 

June 13, 2007, was deemed complete by 

operation of law on December 13, 2007. 

IV. Review of the 2007 Ozone Plan for 

Phoenix-Mesa 

EPA evaluated the 2007 Ozone Plan 

according to the general subpart 1 

nonattainment plan requirements 

contained in section 172(c) of the Act. 

A. Emission Inventories 

1. Requirements for Emissions 

Inventories 

CAA section 172(c)(3) requires each 

state with an ozone nonattainment area 

to submit plan provisions that include 

a ‘‘comprehensive, accurate, current 

inventory of actual emissions from all 

sources of the relevant pollutant or 

pollutants in such area, including such 

periodic revisions as the Administrator 

may determine necessary to assure that 

the requirements of this part are met’’. 

EPA has issued the ‘‘Emissions 

Inventory Guidance for Implementation 

of Ozone and Particulate Matter 

National Ambient Air Quality Standards 

(NAAQS) and Regional Haze 

Regulations’’ (EI Guidance),11 which 

provides guidance on how to develop 

base year and future year baseline 

emission inventories for 8-hour ozone, 

PM2.5, and regional haze SIPs. For areas 

designated nonattainment for the 8-hour 

ozone standard in 2004, EPA 

recommends using calendar year 2002 

as the base year for the inventory. EI 

Guidance, p. 8. 

Emissions inventories for ozone 

should include emissions of VOC, NOX

and carbon monoxide (CO) and 

represent an average summer week day 

during the ozone season. See EI 

Guidance, pp. 14 and 17. States should 

include documentation in their 

submittals explaining how the 

emissions data were calculated. See 70 

FR 71612 (Nov. 29, 2005) and EI 

Guidance p. 40. In estimating mobile 

source emissions, states should use the 

latest emissions models and planning 

assumptions available at the time the 

SIP is developed. See 68 FR 32802 (June 

2, 2003) and 70 FR 71612 (Nov. 29, 

2005). 

2. Emission Inventories in the 2007 

8-Hour Ozone Plan 

The base year and future year baseline 

inventories for NOX, CO and VOC for 

the Phoenix-Mesa nonattainment area, 

together with additional documentation 

for the inventories, are found in Volume 

1 of the Appendices to the 2007 Ozone 

Plan.12 These inventories represent 

average summer day (ozone season) 

emissions. A base year inventory is 

provided for 2002 and the projected 

baseline inventory is provided for the 

attainment year of 2008.13 All 

inventories include NOX, CO, and VOC 

emissions from point, area, nonroad 

mobile, and onroad mobile sources, 

except that biogenic emission 

inventories include only NOX and VOC 

emissions. 

The 2002 Periodic Emission Inventory 

(PEI) emissions estimates for Maricopa 

County and the Phoenix-Mesa 

nonattainment area, which provided the 

basis for the 2002 base year inventory, 

were 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 emission 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. Nonroad 

mobile source emissions were estimated 

with the EPA NONROAD 2002 model 

and onroad mobile source emissions 

were estimated from emission factors for 

various vehicle classes from MOBILE6.2 

combined with estimates of vehicle 

miles traveled (VMT) using data 

submitted by the Arizona Department of 

Transportation to the U.S. Department 

of Transportation’s Federal Highway 

Administration for the 2002 Highway 

Performance and Monitoring System. 

Biogenic emissions of NOX and VOC 

were calculated using MAGBEIS2, a 

modified version of the UAM–BEIS2 

model developed specifically for use in 

Maricopa County, based on land use 


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14Email from Cathy Arthur, MAG, to Anita Lee, 

EPA, re: ‘‘Biogenic VOCs’’ on February 8, 2012, plus 

two attachments on land use boundaries and 

emission factors. 

15 Ibid. 

16 Ibid. 

information, surface temperature data, 

and emission factors for land use 

categories. See 2002 Periodic Emissions 

Inventory for Ozone Precursors, June 

2004 in Volume 1 of the Appendices to 

the 2007 Ozone Plan. 

Ozone precursor emissions from 

point, area, onroad, and nonroad 

sources used in the modeling domain 

(Table 1) were developed from the 

Comprehensive Air Quality Model with 

Extensions (CAMx), version 4.40, and 

the Emissions Preprocessor System 

(EPS3.0), based on the 2002 Periodic 

Emission Inventory for the three ozone 

episodes modeled for 2002. Biogenic 

VOC emission estimates used for the 

2002 modeling domain (e.g., 451.3 

metric tons per day in the June 2002 

ozone episode) are significantly higher 

than biogenic VOC emissions estimated 

in the 2002 PEI (e.g., 41.7 metric tons 

per ozone season day). Section III of 

Appendix A, Exhibit 2 of the 2007 

Ozone Plan describes the method used 

to estimate biogenic emissions for the 

modeling domain. MAG used a model 

developed in 2005, called Model of 

Emissions of Gases and Aerosols from 

Nature (MEGAN), that was determined 

to be more reliable and accurate for 

Maricopa County because it relies on 

local field studies that identified 

dominant plant species and emission 

factors, as well as locations and biomass 

densities, to estimate biogenic emissions 

of ozone precursors. In the 2002 base 

year inventory, biogenic sources 

contributed 65 percent to total VOC 

emissions. In contrast, anthropogenic 

onroad mobile sources dominated the 

total NOX emissions and accounted for 

63 percent of total NOX. See Tables 

5–3 and 5–4 of the 2007 Ozone Plan. 

The 2002 inventory was projected to 

2008 by accounting for expected growth 

factors, ongoing control programs, and 

retirement rates for obsolete sources of 

emissions. MAG accounted for known 

projects in 2008 (e.g., the Phoenix 

Expansion Project of the Transwestern 

Pipeline Company) and additionally 

applied a five percent increase to 

onroad mobile source emissions of NOX

and a three percent increase to all other 

anthropogenic emissions of VOC and 

NOX. The three percent increase was 

based on population projections 

prepared by the Arizona Department of 

Economic Security, based on a 2005 

special census in Maricopa County. 

MAG applied the five percent increase 

to onroad mobile source emissions of 

NOX to create a safety margin for 

transportation conformity. See 2007 

Ozone Plan, p. 5–5, and Appendices to 

Ozone Plan, Volume 1. 

For biogenic emissions, the 2002 

inventory was held constant for 2008. In 

additional information provided to EPA, 

MAG explained that no projected land 

use or land cover data was available for 

the 2008 attainment year, therefore 

biogenic emissions in the ozone 

modeling domain were held constant.14

In the approved 1-hour ozone 

maintenance plan, MAG projected an 

increase in VOC emissions from the 

Phoenix Metropolitan nonattainment 

area due to changes in land use, i.e., 

increasing urbanization and residential 

land use and decreasing use of land for 

agriculture. See 70 FR 13425 (Mar. 21, 

2005). The 1-hour ozone maintenance 

plan relied on MAGBEIS2 to estimate 

biogenic emissions from the 

nonattainment area and modeling 

domain.15 As shown in the additional 

information provided by MAG on 

February 8, 2012, the MAGBEIS2 VOC 

emission factor for urbanized land use 

is greater than the VOC emission factor 

for agricultural land use, therefore, 

based on the projected increased 

urbanization in the 1-hour ozone 

nonattainment area, VOC emissions 

projected by MAGBEIS2 increased from 

the 1999 base year to the 2015 

maintenance year. In contrast, as 

described above, the 2007 8-hour ozone 

plan relied on a new biogenic emissions 

model (MEGAN) that is more 

representative of Maricopa County and 

its desert environment. The additional 

information provided by MAG shows 

the urbanized land use emission factors 

from MEGAN are lower than emission 

factors associated with agriculture or 

other undeveloped desert landscapes in 

Maricopa County. Therefore, using 

MEGAN, MAG expects that the trend of 

increasing urbanization (as projected in 

the 1-hour ozone maintenance plan) is 

expected to decrease VOC emissions 

from 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.16

TABLE 1—EMISSION INVENTORIES FOR THE PHOENIX-MESA MODELING DOMAIN FOR JUNE OZONE EPISODE

[Metric tons per day] 

NOX VOC 

2002 2008 2002 2008 

Point ................................................................................................................................................. 11.15 32.78 11.72 13.55 

Area ................................................................................................................................................. 9.79 13.49 90.56 105.03 

Nonroad Mobile ............................................................................................................................... 79.97 86.58 50.73 57.55 

Onroad Mobile ................................................................................................................................. 182.36 145.52 91.84 72.34 

Biogenics ......................................................................................................................................... 8.56 8.56 451.28 451.28 

Total .......................................................................................................................................... 291.82 286.93 696.13 699.75 

Source: 2007 Ozone Plan at Tables 5–3 and 5–4. 

3. Proposed Action on the Emission 

Inventories 

We have reviewed the 2002 base year 

inventory and the inventory 

methodologies used in the 2007 Ozone 

Plan and believe that the inventory was 

developed consistent with the CAA 

requirements as reflected in the 8-hour 

ozone implementation rule and EPA’s 

guidance. The 2002 base year inventory 

is a comprehensive inventory of actual 

emissions of ozone precursors in the 

Phoenix-Mesa nonattainment area. We 

therefore propose to approve the base 

year inventory as meeting the 

requirements of CAA section 172(c)(3) 

and EPA’s 8-hour ozone implementation 

rule. 


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17The ‘‘General Preamble for the Implementation 

of Title I of the Clean Air Act Amendments of 

1990’’, published at 57 FR 13498 on April 16, 1992, 

describes EPA’s preliminary view on how we 

would interpret various SIP planning provisions in 

title I of the CAA as amended in 1990, including 

those planning provisions applicable to the 1-hour 

ozone standard. EPA continues to rely on certain 

guidance in the General Preamble to implement the 

8-hour ozone standard under title I. 

18See also ‘‘State Implementation Plans; General 

Preamble for Proposed Rulemaking on Approval of 

Plan Revisions for Nonattainment Areas’’, 44 FR 

20372 (April 4, 1979), and Memorandum dated 

December 14, 2000 from John S. Seitz, Director, 

Office of Air Quality Planning and Standards, 

‘‘Additional Submission on RACM from States with 

Severe One-Hour Ozone Nonattainment Area SIPs’’. 

19See, e.g., 2007 Ozone Plan at Table 1–1; 68 FR 

2912 (January 22, 2003); 69 FR 10161 (March 4, 

2004); 70 FR 30370 (May 26, 2005); 70 FR 13425 

(March 21, 2005) (proposed redesignation of 

Phoenix to attainment for the 1-hour standard) and 

70 FR 34362 (June 14, 2005) (final redesignation). 

RACT rules for NOX were not required for purposes 

of attaining and maintaining the 1-hour ozone 

NAAQS in Phoenix-Mesa because EPA approved a 

petition for NOX exemption for this purpose. 60 FR 

19510 (April 19, 1995). 

20The 2007 Ozone Plan refers to these seven 

control measures as ‘‘attainment measures,’’ to be 

distinguished from ‘‘baseline measures,’’ which 

were taken into account in the base year and 

projection year emission inventories. See 2007 

Ozone Plan at 4–2 and Volume 1 of the Appendices 

to the 2007 Ozone Plan at Table III–1. 

B. Reasonably Available Control 

Measures Demonstration and Control 

Strategy 

1. Requirements for RACM and Control 

Strategies 

CAA Section 172(c)(1) requires that 

each attainment plan ‘‘provide for the 

implementation of all reasonably 

available control measures as 

expeditiously as practicable (including 

such reductions in emissions from 

existing sources in the area as may be 

obtained through the adoption, at a 

minimum, of reasonable available 

control technology), and shall provide 

for attainment of the national primary 

ambient air quality standards.’’ The 8- 

hour ozone implementation rule 

requires that for each nonattainment 

area that is required to submit an 

attainment demonstration, the state 

must also submit concurrently a SIP 

revision demonstrating that it has 

adopted all RACM necessary to 

demonstrate attainment as expeditiously 

as practicable and to meet any RFP 

requirements. 40 CFR 51.912(d). 

EPA has previously provided 

guidance interpreting the RACM 

requirement in the General Preamble at 

13560 17 and in a memorandum entitled 

‘‘Guidance on the Reasonably Available 

Control Measure Requirement and 

Attainment Demonstration Submissions 

for Ozone Nonattainment Areas’’, John 

Seitz, Director, OAQPS to Regional Air 

Directors, November 30, 1999 (Seitz 

memo). In summary, EPA guidance 

provides that, to address the 

requirement to adopt all RACM, states 

should consider all potentially 

reasonable control measures for source 

categories in the nonattainment area to 

determine whether they are reasonably 

available for implementation in that 

area and whether they would, if 

implemented individually or 

collectively, advance the area’s 

attainment date by one year or more. 

See Seitz memo and General Preamble 

at 13560.18 Any measures that are 

necessary to meet these requirements 

that are not already either federally 

promulgated, part of the state’s SIP, or 

otherwise creditable in SIPs must be 

submitted in enforceable form as part of 

a state’s attainment plan for the area. 

CAA section 172(c)(6) requires 

nonattainment plans to ‘‘include 

enforceable emission limitation, and 

such other control measures, means, or 

techniques (including economic 

incentives such as fees, marketable 

permits, and actions of emission rights), 

as well as schedules and timetables for 

compliance, as may be necessary or 

appropriate to provide for attainment of 

such standard in such area by the 

applicable attainment date * * *.’’ See 

also CAA section 110(a)(2)(A). The 

ozone implementation rule requires that 

all control measures needed for 

attainment be implemented no later 

than the beginning of the attainment 

year ozone season. See 40 CFR 

51.908(d). The attainment year ozone 

season is defined as the ozone season 

immediately preceding a nonattainment 

area’s attainment date. See 40 CFR 

51.900(g). 

2. RACM Demonstration and the Control 

Strategy in the 2007 Ozone Plan 

The attainment demonstration for the 

Phoenix-Mesa nonattainment area, 

which we discuss further in section 

IV.D of this document, shows that 

implementation of all of the measures 

identified as RACM for the 1997 8-hour 

ozone NAAQS would enable the 

Phoenix-Mesa area to attain the 1997 

8-hour ozone standard during the 2008 

ozone season, preceding the 2009 

attainment date for the area. EPA 

previously approved all of the key NOX

and VOC control measures, including 

several dozen VOC RACT rules, as part 

of Arizona’s plans for attaining and 

maintaining the 1-hour ozone standard 

in Phoenix-Mesa.19 The 2007 Ozone 

Plan specifically relies on seven of these 

control measures to demonstrate 

attainment of the 1997 8-hour ozone 

standard by June 15, 2009, and provides 

for implementation of these measures by 

the beginning of the attainment year 

ozone season (January 2008), consistent 

with the requirements of 40 CFR 

51.908(d). See 2007 Ozone Plan at pp. 

4–2 through 4–7.20 We discuss below 

the seven measures that the attainment 

demonstration in the 2007 Ozone Plan 

relied on to reduce emissions of VOC 

and/or NOX (see Table 2). Emission 

reductions associated with each 

measure were estimated for the June 

2008 ozone episode modeled for the 

attainment demonstration. Of these 

seven measures, phased-in emission test 

cutpoints and the development of 

intelligent transportation systems 

resulted in the greatest reduction in 

VOC emissions, and the summer fuel 

reformulation resulted in the greatest 

reduction in NOX emissions. 

TABLE 2—2008 EMISSION REDUCTIONS FROM ‘‘ATTAINMENT MEASURES’’ 

VOC NOX

Metric ton/day 

reduction 

% Change 

compared to 

2008 base 

case 

Metric ton/day 

reduction 

% Change 

compared to 

2008 base 

case 

Summer Fuel Reformulation .......................................................................... 1 (0.1 ) 1 <0.1 10.3 3.5 

Phased-in Emission Test Cutpoints .............................................................. 3.1 1.2 2.6 0.9 

One Time Waiver from Vehicle Emissions Test ............................................ 0.1 <0.1 <0.1 <0.1 

Coordinate Traffic Signal Systems ................................................................ <0.1 <0.1 <0.1 <0.1 

Develop Intelligent Transportation Systems .................................................. 2.2 0.9 0.4 0.1 

Tougher Enforcement of Vehicle Registration and Emission Test Compliance ............................................................................................................ 0.2 <0.1 0.1 <0.1 


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TABLE 2—2008 EMISSION REDUCTIONS FROM ‘‘ATTAINMENT MEASURES’’—Continued 

VOC NOX

Metric ton/day 

reduction 

% Change 

compared to 

2008 base 

case 

Metric ton/day 

reduction 

% Change 

compared to 

2008 base 

case 

Rule 358: Polystyrene Foam Operations ...................................................... 0.5 0.2 N/A N/A 

Total ........................................................................................................ 6.0 2.4 13.4 4.6 

Source: 2007 Ozone Plan at Table 5–2. 

1 Increase. 

a. Summer Fuel Reformulation 

The 2007 Ozone Plan relies on H.B. 

2307, a Cleaner Burning Gasoline (CBG) 

program passed by the Arizona 

Legislature in 1997. The CBG program 

contains requirements related to 

seasonal changes in gasoline 

formulation related to vapor pressure 

and oxygen content. Typically, fuel 

reformulation measures are designed to 

reduce summertime evaporative VOC 

emissions. However, the results of 

MAG’s emissions modeling analyses 

suggest that the summer reformulation 

measure would increase VOC emissions 

slightly and significantly reduce 

emissions of NOX. In Volume 2 of the 

Appendices to the 2007 Ozone Plan, in 

response to EPA comments, MAG 

explains that the slight increase in 

projected VOC emissions from the 

summer fuel reformulation measure 

occurred because the MOBILE6.2 input 

for the measure specified a Reid vapor 

pressure (RVP) of 7.0 pounds per square 

inch (psi). Actual fuel specifications for 

the 2002 base case used actual fuel 

specifications from the Arizona 

Department of Weights and Measures 

that were lower than 7.0 psi. The 

projected decrease in NOX emissions in 

2008 from the summer fuel 

reformulation measure is a result of the 

removal of the summertime (April 1 

through November 1) minimum oxygen 

content standard for Type 1 gasoline. 

Oxygenates in fuel are used to improve 

combustion as a control strategy for CO 

and other products of incomplete 

combustion, for example unburned 

VOCs; however improved combustion 

also tends to increase formation of NOX. 

Therefore, removal of the minimum 

summertime oxygenate standard is 

projected to reduce formation of NOX. 

See 2007 Ozone Plan at 4–2, 4–3. 

b. Phased-in Emission Test Cutpoints 

The 2007 Ozone Plan describes two 

measures passed by the Arizona 

Legislature that comprise this 

attainment measure: H.B. 2237, passed 

in 1997, that appropriates funds from 

the State General Fund to develop and 

implement an alternative test protocol 

to reduce false failure rates associated 

with the more stringent standards for 

the Vehicle Emissions Testing Program, 

and S.B. 1427, which requires vehicles 

in certain areas to be emission tested 

and requires owners of the newest five 

model year vehicles to be exempt from 

testing but to pay an in lieu fee that is 

deposited into the Arizona Clean Air 

Fund, effective December 31, 1998. 

Using MOBILE6.2, MAG estimated that 

this measure reduces NOX emissions by 

2.6 metric tons per day in the June 2008 

ozone episode and VOC emissions by 

3.1 metric tons per day. See 2007 Ozone 

Plan at 4–3, 4–4. 

c. One Time Waiver From Vehicle 

Emissions Test 

The Arizona Legislature passed S.B. 

1002 which limits issuance of a waiver 

for failure to comply with emission 

testing requirements to one-time only, 

effective January 1, 1997. MAG modeled 

this measure in MOBILE6.2 by adjusting 

the percentage of waivers allowed and 

estimated that this measure reduces 

NOX emissions by less than 0.1 metric 

tons per day in the June 2008 ozone 

episode and VOC emissions by 0.1 

metric tons per day. See 2007 Ozone 

Plan at 4–4. 

d. Coordinate Traffic Signal Systems 

House Bill 2237 passed by the 

Arizona Legislature contains 

appropriations for fiscal years 1997– 

1998 and 1998–1999 to Arizona 

Department of Transportation for 

distribution to cities and counties for 

synchronization of traffic signals within 

and across jurisdictional boundaries. 

MAG modeled this measure in 

MOBILE6.2 by adjusting the input for 

idling time at traffic signals and 

estimated that this measure reduces 

NOX emissions by less than 0.1 metric 

tons per day in the June 2008 ozone 

episode and VOC emissions by less than 

0.1 metric tons per day. See 2007 Ozone 

Plan at 4–4, 4–5. 

e. Develop Intelligent Transportation 

Systems 

The 2007 Ozone Plan cites three 

committed control measures in the 

1-hour Ozone Maintenance Plan that 

serve to reduce traffic congestion: 

‘‘Coordinate Traffic Signal Systems’’, 

‘‘Develop Intelligent Transportation 

Systems’’, and ‘‘Reduce Traffic 

Congestion at Major Intersections’’. The 

2007 Ozone Plan describes these 

measures as technologies implemented 

on the local level over fiscal years 2003– 

2006 that reduce VOC and NOX

emissions by reducing congestion. MAG 

estimated emission reductions from 

these measures to be 0.4 metric tons of 

NOX per day in the June 2008 ozone 

episode and 2.2 metric tons of VOC per 

day. See 2007 Ozone Plan at 4–5. 

f. Tougher Enforcement of Vehicle 

Registration and Emission Test 

Compliance 

The 2007 Ozone Plan cites two 

measures from the Arizona Legislature 

and a program implemented by the 

Arizona Motor Vehicle Division of the 

Arizona Department of Transportation 

that collectively improve enforcement of 

vehicle registration and compliance 

with vehicle testing requirements: S.B. 

1427 passed in 1998 that requires school 

and special districts in certain areas to 

prohibit employees who have not 

complied with emission testing 

requirements from parking in employee 

parking lots, and H.B. 2254 passed in 

1999 that requires vehicles owned by 

federal, state, or political state 

subdivisions in Arizona to comply with 

A.R.S 49–542. MAG modeled this 

measure in MOBILE6.2 by adjusting the 

weighting between inspection and 

maintenance (I/M) and non-I/M 

emission factors, and estimated that this 

measure reduces NOX emissions by 0.1 

metric tons per day in the June 2008 

ozone episode and VOC emissions by 

0.2 metric tons per day. See 2007 Ozone 

Plan at 4–5, 4–6. 


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g. Maricopa County Rule 358: 

Polystyrene Foam Operations 

Rule 358 adopted by Maricopa County 

on April 20, 2005 limits VOC emissions 

from the manufacturing of expandedpolystyrene products. MAG relied on 

information provided by the Maricopa 

County Air Quality Department that 

Rule 358 would result in 80 percent 

control effectiveness and 80 percent rule 

effectiveness. MAG estimated VOC 

emission reductions to be 0.5 metric 

tons per day in the June 2008 ozone 

episode, with no effect on emissions of 

NOX. See 2007 Ozone Plan at 4–6, 4–7. 

3. Proposed Actions on the RACM 

Demonstration and Control Strategy 

Based on our review of the RACM 

analysis and Arizona’s adopted rules, 

we propose to find that the 2007 Ozone 

Plan provides for implementation of all 

reasonably available control measures 

necessary to demonstrate expeditious 

attainment of the 1997 8-hour ozone 

standard and to meet any related RFP 

requirements in the Phoenix-Mesa 

nonattainment area, consistent with the 

applicable requirements of CAA section 

172(c)(1) and 40 CFR 51.912. 

C. Attainment Demonstration 

1. Requirements for Attainment 

Demonstration 

CAA section 172(c)(1) requires states 

with ozone nonattainment areas to 

submit plan provisions that provide for 

attainment of the national ambient air 

quality standards. See also 40 CFR 

51.908. The attainment demonstration 

should include: 

a. Technical analyses to locate and 

identify sources of emissions that are 

causing violations of the 8-hour ozone 

NAAQS within the nonattainment area; 

b. Adopted measures with schedules 

for implementation and other means 

and techniques necessary and 

appropriate for attainment; and 

c. Contingency measures required 

under section 172(c)(9) of the CAA. 

See 70 FR 71612 (Nov. 29, 2005). 

The requirements for the first two 

items are described in the sections on 

emission inventories and RACM/RACT 

above (sections IV.A and IV.B) and in 

the sections on air quality modeling and 

attainment demonstration that follow 

immediately below. Requirements for 

the third item are described in the 

section on contingency measures (IV.F.). 

2. Air Quality Modeling in the PhoenixMesa 2007 Ozone Plan 

Under EPA’s ozone implementation 

rule, an attainment demonstration must 

meet the air quality modeling and other 

requirements of 40 CFR 51.112 and 

must be supported ‘‘by means of a 

photochemical grid model or any other 

analytical method determined by [EPA] 

to be at least as effective.’’ See 40 CFR 

51.908. Air quality modeling is used to 

establish attainment emissions targets, 

that is, a combination of ozone 

precursor emission levels that the area 

can accommodate without exceeding 

the NAAQS, and to assess whether the 

proposed control strategy will result in 

attainment of the NAAQS. 

Air quality modeling is performed for 

a base year and compared to air quality 

monitoring data from that year in order 

to evaluate model performance. Once 

the performance is determined to be 

acceptable, future year changes to the 

emissions inventory are simulated with 

the model to determine the effect of 

emissions reductions on ambient air 

quality. The procedures for modeling 

ozone as part of an attainment 

demonstration are contained in 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’’ (Guidance). The 

Guidance also recommends that 

supplemental analyses be performed, 

and used in combination with the 

modeling in a Weight of Evidence 

determination that the control strategy 

will result in attainment of the NAAQS. 

See Guidance p. 17. 

The air quality modeling is described 

in Chapter 3 of the 2007 Ozone Plan and 

documented in Volume One of the 

Appendices to the 2007 Ozone Plan, in 

Appendix A, Exhibit 2 (‘‘Modeling 

TSD’’). We provide a brief description of 

the modeling and a summary of our 

evaluation of it below. 

MAG performed the air quality 

modeling for the 2007 Ozone Plan using 

the Comprehensive Air Quality Model 

with Extensions (CAMx) photochemical 

model, incorporating meteorological 

fields from the Mesoscale Model version 

5 (MM5). These models have been 

extensively used in developing SIP 

attainment demonstrations and are 

identified in EPA Guidance as candidate 

models. See Guidance pp. 139 & 160. 

While there was no intensive field study 

for this modeling effort, 31 ozone 

stations and 56 meteorological stations 

provided an ample database of routinely 

collected data for use in model 

application development and 

performance evaluation. 

EPA recommends that States prepare 

modeling protocols as part of their 

modeled attainment demonstrations. 

Guidance, p. 133. The Guidance at pp. 

133–134 describes the topics to be 

addressed in this modeling protocol. A 

modeling protocol should detail the 

procedures for conducting the modeling 

analysis, such as the background and 

objectives, the schedule and 

organizational structure, selection of 

ozone episodes to model, meteorological 

and emissions input data preparation, 

model performance evaluation, 

interpreting modeling results, and 

procedures for using the model to 

demonstrate whether proposed 

strategies are sufficient to attain the 

NAAQS. The 2007 Ozone Plan’s 

modeling protocol is contained in 

Volume Two of the Appendices to the 

2007 Plan, in Appendix I-i, and covers 

all of the topics recommended in the 

Guidance. 

A key part of the modeling protocol 

is the selection of ozone episodes to be 

modeled. An attainment demonstration 

that is robust despite natural variability 

should include modeling of multiple 

days with high ozone concentrations, 

spanning the range of meteorological 

conditions that lead to exceedances of 

the NAAQS in the area. See Guidance 

p. 146. Volume two of the Appendices 

to the 2007 Ozone Plan, Attachment II, 

has a thorough description of the 

episode selection process. A climatology 

of high ozone days for 1987–2004 was 

prepared, considering synoptic 

meteorological conditions, temperature, 

wind speed, wind direction, and 

frequency of high ozone by month, day 

of week, and hour of day. For the more 

recent 2000–2004 period, ozone spatial 

patterns were examined, and back 

trajectories prepared to help assess 

whether ozone was locally generated or 

partly due to transport from outside the 

domain. High temperature occurred on 

summer days whether they exceeded 

the standard or not, and so was not 

useful in selecting episodes. Typical 

features of episodes are high ozone 

concentrations northeast of central 

Phoenix and winds from the east in the 

morning, shifting to south at midday, 

and then southwesterly in the afternoon. 

Based on the analysis, MAG identified 

three meteorological regimes leading to 

high ozone concentrations, and six 

candidate recent ozone episodes. On the 

basis of ozone episode severity and 

duration, MAG chose three of the 

episodes for modeling. Regime 1 is 

characterized by stagnant winds and 

purely local generation of ozone; it 

includes some weekend exceedances. It 

is represented by the July 8–14, 2002 

episode with a maximum ozone 

concentration of 107 ppb at Maryvale, 

and eight other exceeding sites; this was 

the episode with the highest ozone 

concentration during the 2000–2004 

period. Regime 2 is characterized by 

light winds, with potential for transport 


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from the south and southwest. It is 

represented by the June 3–7, 2002 

episode with a maximum ozone 

concentration of 92 ppb at Fountain 

Hills, and eleven other exceeding sites. 

Regime 3 is characterized by a non-calm 

winds from other directions. It is 

represented by the August 5–11, 2001 

episode with a maximum ozone 

concentration of 99 ppb at Cave Creek, 

and four other exceeding sites. (Both 

regimes 2 and 3 occur in this episode.) 

The regimes had in common low wind 

speeds, partial cloud cover, and a low 

pressure system in the southwest of the 

State and a high pressure system in the 

northeast. EPA finds the selection 

process to be well-documented and 

well-reasoned, and the selected 

episodes to be a good basis for the 

attainment demonstration. 

Section IV of the Modeling TSD in 

Volume one of the Appendices to the 

2007 Ozone Plan includes extensive 

statistical and graphical analysis 

demonstrating adequate overall model 

performance for the June 2002 episode, 

but also shows consistent 

underprediction for the August 2001 

and July 2002 episodes. Under EPA 

Guidelines, models are used in a 

relative sense (see discussion on 

Relative Response Factors below), so 

although underpredictions in model 

performance do not necessarily mean 

that future design values would be 

underpredicted, they do suggest that 

these two episodes may be less reliable 

for predicting the effect of emissions 

changes. Thus, primary weight was 

given to the June 2002 episode in the 

attainment demonstration. CAMx model 

diagnostic sensitivity tests were 

performed by MAG to provide assurance 

that the model is adequately simulating 

the physical and chemical processes 

leading to ozone in the atmosphere and 

that the model responds in a 

scientifically reasonable way to 

emissions changes. The tests included 

zeroing out boundary condition 

concentrations, initial condition 

concentrations, and various categories 

of emissions. The model responded in a 

physically reasonable way in each of 

these tests. MAG also undertook 

sensitivity tests for MM5, which 

provides meteorological input to the 

CAMx air quality model. These are 

described in Appendix III to the 

Modeling TSD, and included 

incorporation of alternative 

observational data sets, and an 

alternative convection scheme to avoid 

overestimating convective rainfall in 

this dry southwestern area. The 

meteorological model was found to 

perform adequately for wind speed, 

wind direction, temperature, and 

humidity. EPA finds the procedures 

MAG followed to be well-documented 

and reasonable, and to be acceptable for 

supporting the modeled attainment 

demonstration. 

For the modeled attainment test, the 

model is used to predict the air quality 

effect of changes in emissions due to 

land use changes, growth, and the effect 

of control measures. Under current EPA 

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. 

Guidance pp. 15, 25, and 155. MAG 

assessed the 2008 effect of the seven 

control measures using the EPAspecified procedure, and found the 

maximum predicted ozone design value 

to be 84 ppb, which is in attainment of 

the ozone NAAQS. It should be noted 

that this result includes 5 percent 

additional NOX to create a safety margin 

for the transportation conformity motor 

vehicle emissions budget. EPA agrees 

that MAG’s modeling demonstrates 

attainment of the ozone NAAQS by 

summer 2008. 

In addition to a modeled attainment 

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 

reductions in ozone at 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. Guidance, p. 29. MAG used a 

variation of the EPA-described 

approach, described in section V of the 

modeling TSD, as a corroboratory 

screening test. The attainment 

demonstration passed this corroboratory 

screening test. EPA notes that 

concentration gradients in the supplied 

spatial isopleth maps appear to be weak 

except in the downtown area where the 

monitoring network is fairly dense and 

the RRFs themselves have only weak 

spatial variation. We believe the plan’s 

Unmonitored Area Analysis is adequate. 

Finally, the Weight of Evidence 

Analysis in Appendix V of the Modeling 

TSD, in Volume two of the Appendices 

to the 2007 Ozone Plan, includes several 

supplemental analyses in support of the 

attainment demonstration. These 

include ozone air quality trends and 

precursor emission trends, both of 

which show continued progress and 

support the conclusion that the 

attainment demonstration is sound. 

Appendix G of Attachment II to the 

modeling protocol, in Volume two of 

the Appendices to the 2007 Ozone Plan 

also illustrated the downward ozone 

trends at all ozone monitors. Other 

analyses examined the sensitivity of the 

model to NOX reductions, the 

representation of VOC speciation in the 

model, the VOC:NOX ratio as a 

photochemical indicator, Process 

Analysis, and examination of Weekday 

vs. Weekend effects. These analyses 

provided observational and modeling 

evidence that the model is correctly 

replicating the ozone photochemistry of 

the area, and that the Weight of 

Evidence supports the conclusion that 

the Phoenix-Mesa will attain the ozone 

NAAQS in 2008. Additionally, Table 3 

below shows that design values (DV) in 

ppm from all monitors in the PhoenixMesa nonattainment area, operated by 

three different agencies (Pinal County 

Air Quality Control District (PCAQCD), 

Maricopa County Air Quality Division 

(MCAQD), and ADEQ), appear to have 

been meeting the 1997 ozone NAAQS 

based on monitored ozone 

concentrations since 2005. 

EPA proposes to find that the 

modeling provides an adequate basis for 

the RACM/RACT, RFP, and attainment 

demonstrations in the Phoenix-Mesa 

2007 8-Hour Ozone Plan. 

TABLE 3—OZONE DESIGN VALUES FROM 2005–2010 MONITORING DATA IN PHOENIX-MESA NONATTAINMENT AREA* 

Site Site ID Agency 2005–07 2006–08 2007–09 2008–10 

Apache Junction .... 04–013–3001 PCAQCD .......... DV (ppm) ............... 0 .076 0 .080 0 .075 0 .073 

% complete ........... 99 99 99 99 

Buckeye ................. 04–013–4011 MCAQD ............ DV (ppm) ............... 0 .065 0 .066 0 .064 0 .064 


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TABLE 3—OZONE DESIGN VALUES FROM 2005–2010 MONITORING DATA IN PHOENIX-MESA NONATTAINMENT AREA*— 

Continued 

Site Site ID Agency 2005–07 2006–08 2007–09 2008–10 

% complete ........... 100 100 100 100 

Blue Point .............. 04–013–9702 MCAQD ............ DV (ppm) ............... 0 .067 0 .064 0 .067 0 .070 

% complete ........... 100 94 99 99 

Cave Creek ........... 04–013–4008 MCAQD ............ DV (ppm) ............... 0 .079 0 .078 0 .075 0 .074 

% complete ........... 100 100 100 100 

Central Phoenix ..... 04–013–3002 MCAQD ............ DV (ppm) ............... 0 .075 0 .074 0 .070 0 .071 

% complete ........... 99 97 100 100 

Dysart .................... 04–013–4010 MCAQD ............ DV (ppm) ............... 0 .067 0 .067 0 .066 0 .068 

% complete ........... 97 100 100 100 

Falcon Field ........... 04–013–1010 MCAQD ............ DV (ppm) ............... 0 .076 0 .075 0 .071 0 .070 

% complete ........... 97 98 100 100 

Fountain Hill .......... 04–013–9704 MCAQD ............ DV (ppm) ............... 0 .082 0 .079 0 .074 0 .074 

% complete ........... 98 100 99 100 

Glendale ................ 04–013–2001 MCAQD ............ DV (ppm) ............... 0 .075 0 .074 0 .071 0 .072 

% complete ........... 100 100 100 100 

Humboldt Mountain 04–013–9508 MCAQD ............ DV (ppm) ............... 0 .081 0 .078 0 .074 0 .071 

% complete ........... 100 100 99 100 

North Phoenix ........ 04–013–1004 MCAQD ............ DV (ppm) ............... 0 .082 0 .081 0 .076 0 .077 

% complete ........... 99 95 100 100 

Pinnacle Peak ....... 04–013–2005 MCAQD ............ DV (ppm) ............... 0 .078 0 .074 0 .072 0 .073 

% complete ........... 99 99 100 99 

Rio Verde .............. 04–013–9706 MCAQD ............ DV (ppm) ............... 0 .083 0 .080 0 .075 0 .072 

% complete ........... 99 92 96 100 

South Phoenix ....... 04–013–4003 MCAQD ............ DV (ppm) ............... 0 .072 0 .072 0 .071 0 .072 

% complete ........... 99 99 99 100 

South Scottsdale ... 04–013–3003 MCAQD ............ DV (ppm) ............... 0 .078 0 .077 0 .075 0 .074 

% complete ........... 98 97 99 99 

JLG Supersite ........ 04–013–9997 ADEQ ............... DV (ppm) ............... 0 .076 0 .076 0 .075 0 .075 

% complete ........... 100 98 100 99 

Tempe ................... 04–013–4005 MCAQD ............ DV (ppm) ............... 0 .077 0 .077 0 .073 0 .071 

% complete ........... 97 97 100 98 

West Chandler ....... 04–013–4004 MCAQD ............ DV (ppm) ............... 0 .076 0 .076 0 .073 0 .073 

% complete ........... 100 98 100 100 

West Phoenix ........ 04–013–0019 MCAQD ............ DV (ppm) ............... 0 .074 0 .078 0 .073 0 .073 

% complete ........... 100 99 99 99 

* The data in this table has been certified in EPA’s Air Quality System (AQS) database in accordance with the requirements of 40 CFR part 58. 

We provide these data only to support our evaluation of the modeling and attainment demonstration and not to support a determination regarding 

attainment, which is not part of today’s proposed action. 

3. Proposed Action on the Attainment 

Demonstration 

In order to approve a SIP’s attainment 

demonstration, EPA must make several 

findings: 

First, we must find that the 

demonstration’s technical bases, 

emission inventories and air quality 

modeling, are adequate. As discussed in 

section IV.A and IV.C.2, we are 

proposing to approve the base year 

emission inventory and to find the air 

quality modeling adequate to support 

the attainment demonstration. 

Second, we must find that the SIP 

provides for expeditious attainment 

through the implementation of all 

RACM. As discussed above in section 

III.B, we propose to find that the 2007 

Ozone Plan provides for 

implementation of all reasonably 

available control measures necessary for 

expeditious attainment of the 1997 8- 

hour ozone NAAQS and any related 

RFP requirements in the Phoenix-Mesa 

nonattainment area. 

Third, we must find that the emission 

reductions that are relied on for 

attainment are creditable and are 

sufficient to provide for attainment. All 

of the key attainment measures relied on 

in the 2007 Ozone Plan to attain the 

1997 8-hour ozone standard by June 15, 

2009 have been adopted and approved 

into the SIP. 

For the foregoing reasons, we propose 

to approve the attainment 

demonstration in the 2007 Ozone Plan 

for the Phoenix-Mesa nonattainment 

area. 

D. Reasonable Further Progress 

Demonstration 

CAA section 172(c)(2) requires that 

plans for nonattainment areas provide 

for reasonable further progress (RFP). 

RFP is defined in section 171(1) as 

‘‘such annual incremental reductions in 

emissions of the relevant air pollutant as 

are required by [title 1, part D] or may 

reasonably be required by the 

Administrator for the purpose of 

ensuring attainment of the applicable 

[standard] by the applicable date.’’ The 

ozone implementation rule interprets 

the RFP requirements for the purposes 

of the 1997 ozone standards, 

establishing requirements for RFP that 

depend on the area’s classification. For 

areas with attainment dates on or before 

June 15, 2009, RFP would be met by 

ensuring emissions reductions needed 

for attainment are implemented by the 

beginning of the ozone season prior to 

the attainment date. See 40 CFR 

51.910(b) and 70 FR 71612. 

The attainment date for the PhoenixMesa ozone nonattainment area is June 

15, 2009, and as discussed in the RACM 

demonstration and control strategy 

(section IV.B) and the attainment 

demonstration (section IV.C) sections 

above, all of the control measures 

needed for the attainment 

demonstration were being implemented 

prior to the 2008 ozone season. We 

propose, therefore, to approve the RFP 

demonstration in the 2007 Ozone Plan. 


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21Memorandum, G.T. Helms, Chief, Ozone/ 

Carbon Monoxide Programs Branch to Air Directors, 

‘‘Contingency Measures for Ozone and Carbon 

Monoxide Redesignations,’’ June 1, 1992. 

E. Contingency Measures 

1. Requirements for Contingency 

Measures 

CAA section 172(c)(9) requires plans 

to provide for the implementation of 

contingency measures, that achieve 

additional emission reductions, to be 

undertaken if the area fails to meet RFP 

milestones or fails to attain by its 

attainment date. These contingency 

measures must be rules or measures that 

are ready for implementation quickly 

upon failure to meet milestones or 

attainment. The SIP should define 

trigger mechanisms for the contingency 

measures, specify a schedule for 

implementation, and indicate that the 

measures will be implemented without 

significant further action by the State or 

EPA. See 68 FR 32802 (June 2, 2002) 

and 70 FR 71612 (Nov. 29, 2005). 

Additional guidance on the CAA 

contingency measure provisions is 

found in the General Preamble at 

13510–13512 and 13520. The guidance 

indicates that states should adopt and 

submit contingency measures sufficient 

to provide a 3 percent emission 

reduction from the adjusted RFP base 

year. This level of reduction is generally 

acceptable to offset emission increase 

while States are correcting their SIPs. 

These reductions would be beyond what 

is needed to meet the attainment and/ 

or RFP requirement. States may use 

reductions of either VOC or NOX or a 

combination of both to meet the 

contingency measure requirements. 

General Preamble at 13520, footnote 6. 

EPA guidance also provides that 

contingency measures could be 

implemented early, i.e., prior to the 

milestone or attainment date.21

Consistent with this policy, states are 

allowed to use excess reductions from 

already adopted measures to meet the 

CAA section 172(c)(9) and 182(c)(9) 

contingency measure requirement. This 

is because the purpose of contingency 

measures is to provide extra reductions 

that are not relied on for RFP or 

attainment that will provide for 

continued progress while the plan is 

being revised to fully address the failure 

to meet the required milestone. Nothing 

in the CAA precludes a State from 

implementing such measures before 

they are triggered. This approach has 

been approved in numerous SIPs. See 

62 FR 15844 (April 3, 1997) (approval 

of the Indiana portion of the Chicago 

area 15 percent Rate of Progress plan); 

66 FR 30811 (June 8, 2001) (proposed 

approval of the Rhode Island post-1996 

ROP plan); and 66 FR 586 and 66 FR 

634 (January 3, 2001) (approval of the 

Massachusetts and Connecticut 1-hour 

ozone attainment demonstrations). In 

the only adjudicated challenge to this 

approach, the court upheld it. See

LEAN v. EPA, 382 F.3d 575 (5th Cir. 

2004); 70 FR 71612. 

2. Contingency Measures in the 2007 

Ozone Plan 

Contingency measure provisions for 

the Phoenix-Mesa nonattainment area 

and the methodologies used to estimate 

the emission reductions from these 

measures are described in Chapters 4 

and 5 of the 2007 Ozone Plan and 

Section V of Volume 1 of the 

Appendices to the 2007 Ozone Plan. 

Table 4 lists the five contingency 

measures and the estimated reductions 

in VOC and NOX emissions from each 

measure. All five contingency measures 

have already been implemented in the 

Phoenix-Mesa nonattainment area, but 

credit for these measures were not 

needed or used to demonstrate 

attainment. See 2007 Ozone Plan at pp. 

4–7 through 4–10 and 5–15 through 

5–17. 

TABLE 4—EMISSION REDUCTIONS FROM INDIVIDUAL CONTINGENCY MEASURES IN THE PHOENIX-MESA 8-HOUR OZONE

MODELING DOMAIN

Base case emissions on June 6, 2002 VOC 

696.13 metric tons/day 

NOX

291.82 metric tons/day 

Contingency measure Reduction 

(metric ton/ 

day) 

Percent 

reduction 

Reduction 

(metric ton/ 

day) 

Percent 

reduction 

Expansion of Area A Boundaries .................................................................... 1.3 0.2 0.7 0.2 

Gross Polluter Option for I/M Waivers ............................................................. <0.1 <0.1 <0.1 <0.1 

Increased Waiver Repair Limit Options ........................................................... <0.1 <0.1 <0.1 <0.1 

Federal Heavy Duty Diesel Vehicle Standards ............................................... <0.1 <0.1 2.5 0.9 

Federal Nonroad Equipment Standards .......................................................... 14.6 2.1 15.6 5.3 

Total .......................................................................................................... 15.9 2.3 18.8 6.4 

Source: 2007 Ozone Plan at Table 5–6. 

a. Expansion of Area A Boundaries 

In 2001, the Arizona legislature 

passed H.B. 2538 to expand the 

boundaries of Area A, adding additional 

portions of Maricopa County west of 

Goodyear and Peoria and a small area 

on the north side of Lake Pleasant. The 

implementation of air quality measures 

within the new Area A boundaries 

began on January 1, 2002, except for 

public sector alternative fuel 

requirements to be phased in over a 

seven-year period. MAG modeled this 

contingency measure by increasing the 

number of registered vehicles in Area A 

that will be required to participate in 

the I/M program. MAG estimated the 

emission reductions from this 

contingency measure to be 1.3 metric 

tons per day of VOC and 0.7 metric tons 

per day of NOX, but did not take credit 

for this measure in the attainment 

demonstration. See 2007 Ozone Plan at 

4–7 and 4–8. 

b. Gross Polluter Option for I/M Waivers 

The Arizona legislature passed S.B. 

1427 in 1998 to require vehicle owners 

with vehicles emitting more than twice 

the emission standard to repair the 

vehicle sufficiently to reduce the 

emission levels to less than twice the 

standard in order to obtain a compliance 

waiver from the Vehicle Emissions 

Inspection Program. ADEQ modeled the 

emission reductions for this measure 

and estimated the emission reductions 

from this contingency measure to be less 

than 0.1 metric tons per day of VOC and 

less than 0.1 metric tons per day of 

NOX. MAG but did not take credit for 

this measure in its attainment 


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demonstration. See 2007 Ozone Plan at 

4–9. 

c. Increased Waiver Repair Limit 

Options 

In 1998, the Arizona legislature 

passed S.B. 1427 to increase the amount 

a person must spend to repair a failing 

1967–1974 vehicle in Area A in order to 

qualify for a waiver from $100 to $200. 

MAG modeled this measure using 

MOBILE6.2 by reducing the pre-1981 

vehicle waiver rate from 4 to 2.6 

percent. The emission reductions from 

this contingency measure were 

estimated to be less than 0.1 metric tons 

per day of VOC and less than 0.1 metric 

tons per day of NOX. MAG did not take 

credit for this measure in its attainment 

demonstration. See 2007 Ozone Plan at 

4–9. 

d. Federal Heavy Duty Diesel Vehicle 

Standards 

On January 18, 2001, EPA issued a 

final rule that set more stringent 

emission standards for new heavy duty 

diesel vehicles (66 FR 5001). The rule 

requires high-efficiency catalytic 

convertors or comparable technologies 

be installed on 2007 and later model 

year diesel vehicles, and requires ultralow sulfur fuel be used in all onroad 

diesel vehicles beginning in 2006. MAG 

modeled emission reductions from this 

federal measure using MOBILE6.2 and 

estimated VOC reductions of less than 

0.1 metric tons of VOC per day and 2.5 

metric tons of NOX per day. MAG did 

not take credit for this measure in its 

attainment demonstration. See 2007 

Ozone Plan at 4–9. 

e. Federal Nonroad Equipment 

Standards 

On October 23, 1998, EPA issued a 

final rule to set more stringent Tier 2 

and Tier 3 emission standards for new 

diesel nonroad equipment (63 FR 

56967). The Tier 2 program phased in 

more stringent standards for all 

equipment between 2001 and 2006 and 

Tier 3 imposed even more stringent 

standards for 50 to 750 horsepower 

engines in 2006 to 2008. Additionally, 

on June 29, 2004, EPA issued the Clean 

Air Nonroad Diesel—Tier 4 Final rule to 

require manufacturers to produce 

nonroad engines with emission controls 

that will reduce emissions by more than 

90 percent (69 FR 38958). The Tier 4 

standards apply to nonroad engines less 

than 25 horsepower beginning in 2008 

and will apply to larger engines over 

2011 to 2015. MAG estimated emission 

reductions from this measure using the 

EPA NONROAD model and projected 

VOC emission reductions of 14.6 metric 

tons of VOC per day and 15.6 metric 

tons of NOX per day. MAG did not take 

credit for this measure in its attainment 

demonstration. See 2007 Ozone Plan at 

4–9 and 4–10. 

3. Proposed Action on the Contingency 

Measures 

We propose to approve the 

contingency measures in the 2007 

Ozone Plan. The contingency measures 

are consistent with EPA guidance that 

recommends a 3 percent emission 

reduction. All contingency measures 

have already been implemented but 

EPA guidance allows for the early 

implementation of contingency 

measures. 

F. Motor Vehicle Emissions Budgets for 

Transportation Conformity 

1. Requirements for Motor Vehicle 

Emission Budgets 

CAA section 176(c) requires federal 

actions in nonattainment and 

maintenance areas to conform to the 

SIP’s goals of eliminating or reducing 

the severity and number of violations of 

the NAAQS and achieving expeditious 

attainment of the standards. Conformity 

to the SIP’s goals means that such 

actions will not: (1) Cause or contribute 

to violations of a NAAQS, (2) worsen 

the severity of an existing violation, or 

(3) delay timely attainment of any 

NAAQS or any interim milestone. 

Actions that involve Federal Highway 

Administration (FHWA) or Federal 

Transit Administration (FTA) funding 

or approval are subject to the EPA’s 

transportation conformity rule, codified 

in 40 CFR part 93, subpart A. Under this 

rule, metropolitan planning 

organizations (MPOs) in nonattainment 

and maintenance areas coordinate with 

state and local air quality and 

transportation agencies, EPA, FHWA, 

and FTA to demonstrate that an area’s 

regional transportation plans (RTP) and 

transportation improvement programs 

(TIP) conform to the applicable SIP. 

This demonstration is typically done by 

showing that estimated emissions from 

existing and planned highway and 

transit systems are less than or equal to 

the motor vehicle emission budgets 

(budgets) contained in the SIP. An 

attainment, maintenance, or RFP SIP 

should establish budgets for the 

attainment year, each required RFP year, 

or last year of the maintenance plan, as 

appropriate. Budgets are generally 

established for specific years and 

specific pollutants or precursors. Ozone 

attainment and RFP plans should 

establish budgets for NOX and VOC. See 

40 CFR 93.102(b)(2)(i). 

Before an MPO may use budgets in a 

submitted SIP, EPA must first determine 

that the budgets are adequate or approve 

the budgets. In order for EPA to find the 

budgets adequate and approvable, the 

submittal must meet the conformity 

adequacy requirements of 40 CFR 

93.118(e)(4) and be approvable under all 

pertinent SIP requirements. To meet 

these requirements, the budgets must 

reflect all of the motor vehicle control 

measures contained in the attainment 

and RFP demonstrations. See 40 CFR 

93.118(e)(4)(v). 

2. Motor Vehicle Emission Budgets in 

the Phoenix-Mesa 2007 Ozone Plan 

The 2007 Ozone Plan for Phoenix 

Mesa included budgets for VOC and 

NOX for the 2008 attainment year. On 

October 4, 2007, we notified ADEQ and 

MAG that we found the MVEB for the 

2008 attainment year adequate for 

transportation conformity purposes. See 

letter from Deborah Jordan, EPA Region 

9, to Nancy Wrona, ADEQ, and Dennis 

Smith, MAG, ‘‘RE: Adequacy Status of 

Motor Vehicle Emissions Budgets in 

Eight-Hour Ozone Plan for the Maricopa 

Nonattainment Area (June 2007)’’, 

October 4, 2007. We published a notice 

of our findings at 72 FR 60666 (October 

25, 2007). The budget for the 2008 

attainment year is represented by 

onroad VOC and NOX emissions for the 

Phoenix-Mesa modeling domain on the 

peak episode day in June 2008 of 72.3 

metric tons per day of VOC and 145.5 

metric tons per day of NOX. MAG used 

geographic information systems (GIS) to 

separate the onroad mobile emissions 

from the Phoenix-Mesa 8-hour ozone 

nonattainment area from the modeling 

domain, resulting in the estimated 2008 

MVEB of 67.9 metric tons per day of 

VOC and 138.2 metric tons per day of 

NOX. 

3. Proposed Action on the Motor 

Vehicle Emission Budgets 

Based on our evaluation of the 2007 

Ozone Plan and the budgets contained 

in it, which reflect all motor vehicle 

control measures contained in the 

attainment and RFP demonstration, we 

are proposing to approve the 2008 

MVEB. 

V. EPA’s Proposed Action 

For the reasons discussed above, EPA 

is proposing to approve Arizona’s 

submitted SIP for attaining the 1997 

8-Hour Ozone Standard in the PhoenixMesa nonattainment area. 

Specifically, EPA is proposing to 

approve under CAA section 110(k)(3) 

the following elements of the 2007 

Ozone Plan for Phoenix-Mesa: 

1. The 2002 base year emission 

inventory as meeting the requirements 


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21702 Federal Register / Vol. 77, No. 70 / Wednesday, April 11, 2012 / Proposed Rules 

of CAA section 172(c)(3) and 40 CFR 

51.915; 

2. The reasonably available control 

measures demonstration as meeting the 

requirements of CAA section 172(c)(1) 

and 40 CFR 51.912(d); 

3. The reasonable further progress 

demonstration as meeting the 

requirements of CAA section 172(c)(2) 

and 40 CFR 51.910; 

4. The attainment demonstration as 

meeting the requirements of CAA 

section 172(c)(1) and 40 CFR 51.908; 

5. The contingency measures for 

failure to make RFP or to attain as 

meeting the requirements of CAA 

section 172(c)(9); and 

6. The motor vehicle emission 

budgets for the attainment year of 2008, 

which are derived from the attainment 

demonstration, as meeting the 

requirements of CAA section 176(c) and 

40 CFR part 93, subpart A. 

VI. 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 

proposes to approve state law as 

meeting Federal requirements and does 

not impose additional requirements 

beyond those imposed by state law. For 

that reason, this proposed 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); 

• 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 (Pub. L. 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, as 

appropriate, disproportionate human 

health or environmental effects, using 

practicable 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. 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Ozone, Nitrogen 

Dioxide, Volatile Organic Compounds. 

Authority: 42 U.S.C. 7401 et seq. 

Dated: March 30, 2012. 

Keith Takata, 

Acting Regional Administrator, EPA Region 

IX. 

[FR Doc. 2012–8729 Filed 4–10–12; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R10–OAR–2010–0724, FRL–9657–3] 

Approval and Promulgation of 

Implementation Plans; Idaho: 

Infrastructure Requirements for the 

1997 8-Hour Ozone National Ambient 

Air Quality Standard; Prevention of 

Significant Deterioration Greenhouse 

Gas Permitting Authority and Tailoring 

Rule 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: EPA is proposing to approve 

the State Implementation Plan (SIP) 

submittals from the State of Idaho 

demonstrating that the Idaho SIP meets 

the requirements of section 110(a)(1) 

and (2) of the Clean Air Act (CAA) for 

the National Ambient Air Quality 

Standard (NAAQS) promulgated for 

ozone on July 18, 1997. EPA is 

proposing to find that the current Idaho 

SIP meets the following 110(a)(2) 

infrastructure elements for the 1997 

8-hour ozone NAAQS: (A), (B), (C), 

(D)(ii), (E)(i), (E)(iii), (F), (G), (H), (J), (K), 

(L), and (M). EPA is taking no action on 

CAA section 110(a)(2)(E)(ii) at this time. 

We will address the requirements of this 

sub-element in a separate action. EPA is 

also proposing to approve a SIP revision 

that applies Idaho’s Prevention of 

Significant Deterioration (PSD) Program 

to greenhouse gas (GHG) emitting 

sources above certain thresholds, 

updates Idaho’s SIP to incorporate by 

reference revised versions of specific 

federal regulations, and removes 

unnecessary language from the SIP due 

to the incorporation by reference of the 

federal NAAQS and PSD regulations. In 

addition, EPA is proposing to rescind 

the Federal Implementation Plan (FIP) 

put in place to ensure the availability of 

a permitting authority for greenhouse 

gas emitting sources in Idaho. 

DATES: Comments must be received on 

or before May 11, 2012. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R10– 

OAR–2010–0724, by any of the 

following methods: 

• www.regulations.gov: Follow the 

on-line instructions for submitting 

comments. 

• Email: R10– 

Public_Comments@epa.gov. 

• Mail: Kristin Hall, EPA Region 10, 

Office of Air, Waste and Toxics (AWT– 

107), 1200 Sixth Avenue, Suite 900, 

Seattle, WA 98101. 

• Hand Delivery/Courier: EPA Region 

10, 1200 Sixth Avenue, Suite 900, 

Seattle, WA 98101. Attention: Kristin 

Hall, Office of Air, Waste and Toxics, 

AWT–107. Such deliveries are only 

accepted during normal hours of 

operation, and special arrangements 

should be made for deliveries of boxed 

information. 

Instructions: Direct your comments to 

Docket ID No. EPA–R10–OAR–2010– 

0724. EPA’s policy is that all comments 

received 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 information 

claimed to be Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Do not submit information that you 

consider to be CBI or otherwise 

protected through www.regulations.gov 

or email. The www.regulations.gov Web 

site is an ‘‘anonymous access’’ system, 

which means EPA will not know your 

identity or contact information unless 


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