ONE-HOUR OZONE REDESIGNATION REQUEST AND

MAINTENANCE PLAN FOR 

THE MARICOPA COUNTY NONATTAINMENT AREA

MARCH 2004
ONE-HOUR OZONE REDESIGNATION REQUEST AND

MAINTENANCE PLAN FOR 

THE MARICOPA COUNTY NONATTAINMENT AREA

Prepared by:

March 2004

Technical Assistance Provided By:

Arizona Department of Environmental Quality

Arizona Department of Transportation

Maricopa County Environmental Services Department

U.S. Environmental Protection Agency
i

ONE-HOUR OZONE REDESIGNATION REQUEST AND MAINTENANCE PLAN

FOR THE MARICOPA COUNTY NONATTAINMENT AREA

TABLE OF CONTENTS

CHAPTER PAGE

EXECUTIVE SUMMARY .............. .............. ........... ES-1

ONE INTRODUCTION .............. .............. ........ 1-1

NATIONAL AMBIENT AIR QUALITY STANDARD

FOR OZONE .............. .............. ........... 1-2

CHARACTERISTICS AND HEALTH EFFECTS

OF OZONE .............. .............. ............. 1-2

NONATTAINMENT AREA .............. .............. . 1-2

HISTORY .............. .............. .............. 1-3

REQUIRED COMPONENTS OF A REDESIGNATION

REQUEST .............. .............. ............. 1-4

TWO REDESIGNATION REQUEST .............. ............ 2-1

REQUIRED COMPONENTS OF A REDESIGNATION

REQUEST .............. .............. ............. 2-1

ATTAINMENT OF THE ONE-HOUR OZONE STANDARD .... 2-1

APPROVAL OF THE OZONE NONATTAINMENT

SIP ELEMENT FOR THE MARICOPA COUNTY AREA ...... 2-8

IMPROVEMENT IN AIR QUALITY DUE TO PERMANENT

AND ENFORCEABLE EMISSION REDUCTIONS ........... 2-8

ATTAINMENT AND MAINTENANCE CONTROL 

MEASURES .............. .............. ............ 2-9

CLEAN AIR ACT SECTION 110 AND

PART D REQUIREMENTS .............. ............. 2-14
ii

CHAPTER PAGE

THREE MAINTENANCE PLAN .............. .............. .... 3-1

MAINTENANCE PLAN CONTROL MEASURES ............ 3-1

EMISSION INVENTORIES .............. .............. . 3-7

MAINTENANCE DEMONSTRATION .............. ...... 3-13

MOBILE SOURCE EMISSIONS BUDGETS FOR OZONE ... 3-13

MONITORING NETWORK/VERIFICATION OF

CONTINUED ATTAINMENT .............. ............ 3-16

CONTINGENCY PROVISIONS .............. .......... 3-17

SUBSEQUENT MAINTENANCE PLAN REVISIONS ........ 3-18
iii

ONE-HOUR OZONE REDESIGNATION REQUEST AND MAINTENANCE PLAN

FOR THE MARICOPA COUNTY NONATTAINMENT AREA

LIST OF TABLES

TABLE PAGE

ES-1 1999 Base Case and 2015 Committed Maintenance Measures ........ ES-4

ES-2 1999 Base Case and 2015 Committed Maintenance Measure VOC

Emissions in the One-Hour Ozone Nonattainment Area .............. ES-5

ES-3 1999 Base Case and 2015 Committed Maintenance Measure NOx

Emissions in the One-Hour Ozone Nonattainment Area .............. ES-6

2-1 2000 Ozone Monitoring Data Summary for the Maricopa County 

Nonattainment Area .............. .............. .............. 2- 3

2-2 2001 Ozone Monitoring Data Summary for the Maricopa County 

Nonattainment Area .............. .............. .............. . 2-4

2-3 2002 Ozone Monitoring Data Summary for the Maricopa County

Nonattainment Area .............. .............. .............. . 2-5

3-1 Committed Maintenance and Contingency Measures in the One-Hour

Ozone Maintenance Plan. .............. .............. ........... 3-3

3-2 Summary of 2015 Emission Reductions in the Nonattainment Area 

From Committed Maintenance Measures Used for Numeric Credit. ....... 3-6

3-3 Summary of NOx Emissions for the July Episode in 1998 

Base Case and 2015 With Committed Maintenance Measures. .......... 3-9

3-4 Summary of VOC Emissions for the July Episode in 1998 Base Case

And 2015 With Committed Maintenance Measures .............. .... 3-10

3-5 Summary of NOx Emissions for the August Episode in 1999 Base

Case, and 2006 and 2015 With Committed Maintenance Measures. ..... 3-11

3-6 Summary of VOC Emissions for the August Episode in 1999 Base

Case, and 2006 and 2015 With Committed Maintenance Measures. ..... 3-12

3-7 The 1998, 1999, 2006, and 2015 Maximum Simulated One-Hour

Ozone Concentrations for Both the July and August Episodes .......... 3-14
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ONE-HOUR OZONE REDESIGNATION REQUEST AND MAINTENANCE PLAN

FOR THE MARICOPA COUNTY NONATTAINMENT AREA

LIST OF FIGURES

FIGURE PAGE

ES-1 One-Hour Ozone Trends (1995-2002) .............. ............. ES-2

ES-2 2015 NOx Emission Reductions From Individual Maintenance 

Measures in the One-Hour Ozone Nonattainment Area .............. ES-7

ES-3 2015 VOC Emission Reductions From Individual Maintenance 

Measures in the One-Hour Ozone Nonattainment Area .............. ES-8

2-1 One-Hour Ozone Regional Monitoring Network .............. ........ 2-6

2-2 One-Hour Ozone Trends (1995-2002) .............. .............. . 2-7

3-1 2015 NOx Emission Reductions From Individual Maintenance 

Measures in the One-Hour Ozone Nonattainment Area .............. . 3-4

3-2 2015 VOC Emission Reductions From Individual Maintenance 

Measures in the One-Hour Ozone Nonattainment Area .............. . . 3-5
v

ONE-HOUR OZONE REDESIGNATION REQUEST AND MAINTENANCE PLAN FOR

THE MARICOPA COUNTY NONATTAINMENT AREA

APPENDICES

APPENDIX A

Exhibit I: 1999 Periodic Ozone Emission Inventory for the Maricopa County,

Arizona Nonattainment Area. Maricopa County Environmental Services

Department. November 2001, Revised August 2002.

Exhibit 2: Technical Support Document for Ozone Modeling in Support of the

One-Hour Ozone Redesignation Request and Maintenance Plan for the

Maricopa County Nonattainment Area. March 2004.

APPENDIX B

Exhibit 1: Resolution to Implement RACT for the One-Hour Ozone Redesignation

Request and Maintenance Plan for the Maricopa County Nonattainment

Area. Maricopa County Board of Supervisors. December 17, 2003.

Exhibit 2: Negative Declaration for Fiberglass Boat Manufacturing. Letter from

Maricopa County to Arizona Department of Environmental Quality.

November 25, 2003.

APPENDIX C

Exhibit 1: Public Hearing Process Documentation

Exhibit 2: Certification of Adoption
ONE-HOUR OZONE REDESIGNATION REQUEST AND

MAINTENANCE PLAN FOR 

THE MARICOPA COUNTY NONATTAINMENT AREA

EXECUTIVE SUMMARY
ES-1

ONE-HOUR OZONE REDESIGNATION REQUEST AND MAINTENANCE PLAN 

FOR THE MARICOPA COUNTY NONATTAINMENT AREA

EXECUTIVE SUMMARY

The Maricopa Association of Governments (MAG) is requesting that the U.S.

Environmental Protection Agency (EPA) redesignate the Maricopa County nonattainment

area to attainment for the National Ambient Air Quality Standards for one-hour ozone. No

violations of the one-hour ozone standard have occurred since 1996. With the submittal

of this redesignation request and maintenance plan, the Maricopa County nonattainment

area has satisfied all of the requirements for redesignation to attainment for one-hour

ozone.

Under the 1990 Clean Air Act Amendments, the Maricopa County nonattainment area was

classified as Moderate for the one-hour ozone standard. Because attainment was not

achieved by November 19, 1996, the area was classified to Serious, effective February 13,

1998, with a new attainment date of November 19, 1999. 

The MAG 1993 Ozone Plan, addressing the Moderate Area requirements, was submitted

to the Environmental Protection Agency (EPA) in November 1993. An Addendum to this

Moderate Area plan was submitted to EPA in March 1994. EPA approved and

promulgated a Revised Rate of Progress Federal Implementation Plan for the Maricopa

County nonattainment area, effective August 5, 1999. In February 2000, the State of

Arizona requested an ozone attainment determination for the Maricopa County area. A

Serious Area Ozone State Implementation Plan (SIP) for Maricopa County was submitted

to EPA in December 2000. On May 30, 2001, EPA published a final attainment

determination for the one-hour ozone standard.

The Clean Air Act defines the following criteria that must be met before a nonattainment

area can be redesignated to attainment:

• EPA must fully approve the Serious Area Ozone SIP for Maricopa County submitted

to EPA in December 2000 and any related SIP components.

• EPA must determine that the area has attained the one-hour ozone standard. This

determination was made by EPA on May 30, 2001.

• EPA must determine that the improvement in air quality is due to permanent and

enforceable reductions in emissions.

• The State must meet all applicable requirements for State Implementation Plans

(SIPs) and Nonattainment Areas as defined in the Clean Air Act.

• EPA must approve a maintenance plan for the area. The plan must demonstrate

maintenance of the one-hour ozone standard for a period of at least ten years

following the redesignation to attainment by EPA. 

Chapter Two of this document provides monitoring data to support the finding that the onehour ozone standard has been met in the nonattainment area since 1996. Figure ES-1

shows the continuous downward trend in ozone concentrations occurring in the

nonattainment area. Chapter Two demonstrates that these improvements in air quality are
ES-2
ES-3

attributable to permanent, enforceable reductions in ozone precursor emissions. The

second chapter also documents that other Clean Air Act requirements for SIPs and

nonattainment areas have been met.

Generally, the overall approach taken in preparing the One-Hour Ozone Maintenance Plan

is to demonstrate maintenance of the one-hour ozone standard in 2015 with the committed

measures in the Revised MAG 1999 Serious Area Carbon Monoxide Plan and Carbon

Monoxide Redesignation Request and Maintenance Plan, since most of those measures

also reduce ozone. Therefore, the Ozone Maintenance Plan relies heavily upon the

Revised MAG Serious Area Carbon Monoxide Plan and its supporting documents,

including the commitments to implement control measures. The Ozone Maintenance Plan

also relies upon the Final Serious Area Ozone State Implementation Plan for Maricopa

County and the modified Arizona Cleaner Burning Gasoline Program.

Chapter Three contains the One-Hour Ozone Maintenance Plan for the nonattainment

area. The Maintenance Plan demonstrates that the area will continue to maintain the onehour ozone standard through 2015, a period of at least ten years following redesignation

to attainment by EPA. Maintenance of the standard through 2015 will be achieved despite

growth in regional population, employment, and vehicle travel, due to more stringent

federal controls on vehicles and fuels, and state and local committed measures in this

Maintenance Plan.

 

Table ES-1 identifies the measures for which numeric credit was taken in validating the air

quality models for 1998 and 1999. The seven committed maintenance measures for which

numeric credit is taken in the Maintenance Plan are also identified in Table ES-1. Six of

these maintenance measures were also committed measures in the Revised MAG 1999

Serious Area Carbon Monoxide Plan and the 2003 Carbon Monoxide Redesignation

Request and Maintenance Plan. CARB Phase 2 gasoline with 3.5 percent oxygenate in

winter was also a committed measure in the Carbon Monoxide Plans. The summertime

formulation of this fuel is a committed measure in the Ozone Maintenance Plan, as

described in the Technical Support Document. Rule 348 is a new measure adopted by

Maricopa County to reduce volatile organic compounds (VOC) emissions from aerospace

manufacturing and rework operations. 

Tables ES-2 and ES-3 compare VOC and nitrogen oxides (NOx ), respectively, in the 1999

base case to emissions in 2015 with the committed maintenance measures. The maximum

one-hour ozone concentration modeled in 1999 was 0.125 parts per million (ppm). The

maximum one-hour ozone concentration in 2015 is projected to be 0.120 ppm, which

demonstrates maintenance of the standard.

 

Figures ES-2 and ES-3 illustrate the emission reductions attributable to each of the

maintenance measures in 2015. With the committed measures, the Maintenance Plan

projects that onroad mobile sources will contribute 15.9 percent of the VOC emissions in

2015 or 48.7 metric tons per day. Onroad mobile sources also contribute 25.4 percent of

the NOx emissions in 2015 or 53.6 metric tons per day. These figures, 48.7 metric tons
ES-4

TABLE ES-1

1999 BASE CASE AND 2015 COMMITTED MAINTENANCE MEASURES

Base Case Measures Assumed in the

1999 Model Validation for the OneHour Ozone Maintenance Plan

Committed Maintenance

Measures Used for Credit in the

One-Hour Ozone Maintenance

Plan

1. Inspection/Maintenance (I/M) idle test

was required for all gasoline vehicles

1. CARB Phase 2 and Federal Phase

II Reformulated Gasoline with 7 psi

from May through September

2. I/M waiver rates of 10% assumed for

pre-1981 model year vehicles and 4%,

for 1981 and newer vehicles

2. Coordinate Traffic Signal Systems

3. Oxygenate content and Reid Vapor

Pressure (RVP) were based on actual

fuel properties from surveys

3. Tougher Enforcement of Vehicle

Registration and Emission Test

Compliance

4. Vehicles participating in I/M test - 88%;

not-participating - 12%

4. One Time Waiver from Vehicle

Emissions Test

5. Expansion of Area A (S.B. 1427) 5. Develop Intelligent Transportation

Systems

6. Phased-in Emission Test Cutpoints

7. Maricopa County Rule 348
ES-5

TABLE ES-2

1999 BASE CASE AND 2015 COMMITTED MAINTENANCE MEASURE VOC EMISSIONS

IN THE ONE-HOUR OZONE NONATTAINMENT AREA

Tuesday, August 1999

Source Category Metric Tons

per Day

Percent

Point 15.3 4.3

Area 82.6 22.9

Biogenics 76.7 21.3

Nonroad Mobile 78.5 21.8

Onroad Mobile 106.9 29.7

Total 360.0* 100.0*

 August 1999

Tuesday, August 2015

Source Category Metric Tons

per Day

Percent

Point 20.2 6.6

Area 123.5 40.2

Biogenics 85.8 28.0

Nonroad Mobile 28.7 9.4

Onroad Mobile 48.7 15.9

Total 306.9* 100.0*

 August 2015

* Note that the sum of the source categories may not equal the total due to rounding.

Point Sources - Industrial, Manufacturing, and Electrical Power Generation Facilities

Area Sources - Residential Wood and Industrial Fuel Combustion, On-site Incineration, and

Open Burning

Biogenics - Natural Vegetation

Nonroad Mobile - Utility, Lawn & Garden, Construction, Farm, and Recreational Equipment,

Aircraft and Locomotives
ES-6

August 1999

August 2015

TABLE ES-3

1999 BASE CASE AND 2015 COMMITTED MAINTENANCE MEASURE NOx EMISSIONS

IN THE ONE-HOUR OZONE NONATTAINMENT AREA

Tuesday, August 1999

Source Category Metric Tons

per Day

Percent

Point 16.5 6.4

Area 43.0 16.8

Biogenics 7.3 2.9

Nonroad Mobile 59.3 23.2

Onroad Mobile 129.8 50.7

Total 255.9* 100.0*

Tuesday, August 2015

Source Category Metric Tons

per Day

Percent

Point 26.3 12.5

Area 67.4 32.0

Biogenics 6.2 2.9

Nonroad Mobile 57.2 27.1

Onroad Mobile 53.6 25.4

Total 210.7* 100.0*

* Note that the sum of the source categories may not equal the total due to rounding.

Point Sources - Industrial, Manufacturing, and Electrical Power Generation Facilities

Area Sources - Residential Wood and Industrial Fuel Combustion, On-site Incineration, and

Open Burning

Biogenics - Natural Vegetation

Nonroad Mobile - Utility, Lawn & Garden, Construction, Farm, and Recreational Equipment,

Aircraft and Locomotives
ES-7
ES-8
ES-9

per day of VOCs and 53.6 metric tons per day of NOx, represent the conformity budgets

for ozone precursor emissions in 2015. In addition, the Maintenance Plan establishes

interim conformity budgets of 71.9 metric tons per day for VOCs and 104.8 metric tons per

day for NOx in 2006. 

The Clean Air Act also requires that a maintenance plan also contain contingency

provisions. The maintenance plan is not required to contain fully adopted contingency

measures. Chapter Three identifies three contingency measures that were also

contingency measures in the Revised MAG 1999 Serious Area Carbon Monoxide Plan.

These measures have already been adopted and implemented in the nonattainment area.

Early implementation of contingency measures is allowed by EPA. The contingency

measures in this Maintenance Plan are: Expansion of Area A Boundaries, Gross Polluter

Option for I/M Program Waivers, and Increased Waiver Repair Limit Options. Chapter

Three describes the process and schedule to be followed if monitoring data indicate

additional measures are needed in the future.
1-1

CHAPTER ONE

INTRODUCTION

The Maricopa Association of Governments (MAG) is requesting that the U.S.

Environmental Protection Agency (EPA) redesignate the Maricopa County nonattainment

area to attainment for the one-hour ozone National Ambient Air Quality Standard. The

area was designated a nonattainment area for ozone in 1978, but has not violated the

standard since 1996. Therefore, the area is now eligible for redesignation. Chapter Two

contains the formal redesignation request and supporting documentation. Chapter Three

provides the Maintenance Plan which demonstrates continued attainment of the one-hour

ozone standard through the year 2015.

In 1978, the Governor of Arizona designated the Maricopa Association of Governments as

the lead air quality planning agency for Maricopa County. Together with the State, MAG

is responsible for determining which elements of the State Implementation Plan will be

planned, implemented and enforced by State and local governments in Arizona. In 1992,

the Arizona Legislature recertified MAG as the regional air quality planning agency. MAG

coordinates with the Arizona Department of Environmental Quality, Arizona Department

of Transportation and the Maricopa County Environmental Services Department in

developing the plans necessary to attain and maintain the national standards.

This redesignation request and Maintenance Plan have been reviewed and approved by

the MAG Air Quality Technical Advisory Committee, the MAG Management Committee and

the MAG Regional Council. The MAG Air Quality Technical Advisory Committee was

established in 1995 with representatives from State, county and local governments, private

industry, environmental groups, and the public-at-large. The Air Quality Technical Advisory

Committee makes recommendations to the MAG Management Committee on air quality

plans, projects, funding and other pertinent issues.

The MAG Management Committee is comprised of managers from each of the MAG

member agencies that include twenty-five cities and towns, the Salt River Pima-Maricopa

and Gila River Indian Communities, Maricopa County, and the Arizona Department of

Transportation. The MAG Management Committee makes recommendations to the MAG

Regional Council. The Regional Council is the MAG decision-making body and is

composed of elected officials from the MAG member agencies. 

MAG has also conducted a public hearing on this redesignation request and maintenance

plan in accordance with federal requirements. All public comments and responses are

provided in Appendix C.
1-2

NATIONAL AMBIENT AIR QUALITY STANDARD FOR OZONE

The federal one-hour ozone standard is 0.12 parts per million (ppm). For the one-hour

standard, a violation occurs when the expected number of exceedances of the standard

that are recorded at a monitoring site during a calendar year and then averaged over a

three year period is greater than one. Four exceedances measured during a three year

period at a single air monitoring station equal one violation of the ozone standard. An

exceedance is considered as a monitored value of 0.125 ppm or greater.

The last exceedance of the one-hour ozone standard in the nonattainment area was

recorded in 1996. There have been no exceedances of the one-hour ozone standard at

any of the ozone monitors located in the nonattainment area in 1997, 1998, 1999, 2000,

2001, and 2002. There have been no violations of the one-hour ozone standard since

1996.

CHARACTERISTICS AND HEALTH EFFECTS OF OZONE

Ozone is not directly emitted from a source, but is produced by the mixing of volatile

organic compounds and nitrogen oxides in the presence of heat and sunlight. Most

precursors to ozone, volatile organic compounds ,and nitrogen oxides are emitted from

onroad and nonroad engines. Other sources of ozone precursors are industrial,

manufacturing and electrical power generation facilities; dry cleaners, service stations,

architectural coatings, and consumer and commercial solvent use; and natural vegetation.

Peak concentrations typically occur in the urban area from May through September when

high temperatures are conducive for forming ozone. Also, due to prevailing afternoon

winds, ozone and ozone precursors are transported to the mountainous areas east and

north of the Maricopa County Nonattainment Area where elevated levels of ozone may

occur.

Ozone irritates the lungs and repeated exposure may cause permanent lung damage.

Symptoms of ozone exposure may include wheezing, coughing, and pain when taking a

deep breath. Children, persons with pre-existing respiratory conditions such as asthma,

and others who are active outdoors when ozone levels are high are most affected by the

adverse health effects of ozone. Even low levels of ozone may cause aggravated asthma,

reduced lung capacity, and make persons more susceptible to respiratory illnesses like

pneumonia and bronchitis.

NONATTAINMENT AREA

The Maricopa County one-hour ozone nonattainment area encompasses 1,946 square

miles in central Arizona. The northern boundary of the nonattainment area is located

approximately six miles north of Carefree Highway and the southern boundary, generally

along Hunt Highway. To the east, the area is bounded by the Pinal County Line and the

Tonto National Forest; on the west, by Jackrabbit Trail and Beardsley Canal. The area

contains portions of twenty-two cities and towns, the Fort McDowell, Gila River and Salt

River Pima-Maricopa Indian Communities, and some unincorporated areas of Maricopa
1-3

County. According to the U.S. Census, the population of Maricopa County in 2000 was 3.1

million. Most of these residents live and work within the nonattainment area boundaries.

The nonattainment area is located in the Salt River Valley at 1,100 feet above mean sea

level and is almost completely surrounded by mountains. The climate in the nonattainment

area is arid continental, with temperatures ranging from a mean of 52 degrees Fahrenheit

in January to 91 degrees, in July. The sun shines 86 percent of the time and the annual

rainfall is about 7.44 inches. In general, the prevailing wind direction is from E/SE to

W/SW, although the winds can shift in the afternoon to a more westerly direction.

HISTORY

In accordance with the Clean Air Act, an urbanized portion of Maricopa County was

formally designated as a nonattainment area for ozone in 1978. Under the 1990 Clean Air

Act Amendments, the nonattainment area was classified as Moderate for ozone. In order

to meet the Moderate area requirements, the MAG 1993 Ozone Plan for the Maricopa

County Area was submitted to the Environmental Protection Agency by November 15,

1993. An Addendum to this Plan containing additional control measures was submitted

to EPA in March 1994.

On April 13, 1994, EPA issued a incompleteness finding on the 1993 Ozone Plan and

Addendum because the plan failed to include, in fully adopted and enforceable form, all

of the measures relied upon in the 15 percent demonstration. This action started a two

year FIP clock under CAA Section 110(c) for EPA to promulgate a 15 percent Rate of

Progress Federal Implementation Plan. In November 1994 the modeling attainment

demonstration for the 1993 Ozone Plan and Addendum was submitted to EPA with a

revision to the modeling attainment demonstration following in April 1995. The MAG 1993

Ozone Plan and Addendum, as well as the attainment demonstration, was found complete

by EPA on May 12, 1995.

Modeling contained in the Revision to the Modeling Attainment Demonstration for the MAG

1993 Ozone Plan for the Maricopa County Area and Addendum concluded that reductions

in NOx would increase ozone concentrations and therefore not contribute to attainment of

the ozone standard. EPA finalized approval of a NOx exemption petition for the Maricopa

County Nonattainment Area on April 19, 1995. Section 182 of the CAA allows for an

exemption when reductions of oxides of nitrogen (NOx) would not contribute to ozone

attainment.

On November 6, 1997, the nonattainment area was reclassified to Serious due to failure

to attain the ozone standard by November 15, 1996. The Serious Area reclassification was

effective on February 13, 1998. Following the outcome of a lawsuit filed to require that

EPA enforce the Federal Implementation Plan provisions in Section 110(c), EPA

promulgated a Federal Implementation Plan for the 15 Percent Rate of Progress

requirement on May 27, 1998.
1-4

On December 14, 2000, the Serious Area Ozone State Implementation Plan for Maricopa

County was submitted to EPA by the Arizona Department of Environmental Quality. In

accordance with Section 110, a completeness finding on the Serious Area Ozone State

Implementation Plan was deemed by operation of law since a determination was not made

by EPA within six months of receipt of the Plan.

While this latest SIP has not been approved under section 110(k), it is anticipated that EPA

approval will occur before this request for redesignation is submitted. If not, approval

action on SIP elements of the Serious Area Ozone State Implementation Plan for Maricopa

County and the redesignation request may occur simultaneously.

On May 30, 2001, EPA determined that the serious ozone nonattainment area had attained

the one-hour ozone standard. The attainment determination was effective June 29, 2001.

EPA also determined that the serious area requirements for reasonable further progress,

attainment determinations, and contingency measures for the one-hour standard would not

apply as long as the area continued to attain the standard.

REQUIRED COMPONENTS OF A REDESIGNATION REQUEST

Sections 107(d)(3)(D) and (E) of the Clean Air Act define the criteria that must be met

before an area can be redesignated to attainment. With the submittal of this redesignation

request and maintenance plan, the Maricopa County nonattainment area meets the five

required criteria, summarized below:

1. Attainment of the Standard

Chapter Two shows that the area has attained the national one-hour ozone standard.

Effective June 29, 2001, EPA determined that the serious ozone nonattainment area had

attained the one-hour ozone standard.

2. State Implementation Plan Approval

On December 14, 2000, the Arizona Department of Environmental Quality submitted the

Serious Area Ozone State Implementation Plan for Maricopa County to EPA. In

accordance with Section 110, a completeness finding was deemed by operation of law.

EPA approval of the plan may be forthcoming.

3. Improvement in Air Quality Due to Permanent and Enforceable Emission

Reductions

Chapter Two discusses the evidence that the improvement in air quality leading to

attainment and maintenance of the standards has been due to permanent and enforceable

emissions reductions.
1-5

4. Clean Air Act Section 110 and Part D Requirements

Chapter Two discusses how requirements of Clean Air Act Section 110 (for SIPs) and Part

D (for nonattainment areas) are satisfied by the Final Serious Area Ozone State

Implementation Plan for Maricopa County and the One-Hour Maintenance Plan provided

in Chapter Three of this document. In addition, some of these requirements are satisfied

by the Revised MAG 1999 Serious Area Carbon Monoxide Plan and MAG Carbon

Monoxide Redesignation Request and Maintenance Plan for the Maricopa County

Nonattainment Area, which were submitted to EPA on April 18, 2001 and June 16, 2003

respectively. Several of the carbon monoxide measures also reduce ozone and have

therefore been included in the Ozone Maintenance Plan.

5. Maintenance Plan

Chapter Three contains the Maintenance Plan for the Maricopa County one-hour ozone

nonattainment area. The Maintenance Plan demonstrates that the area will continue to

maintain the one-hour ozone standard through 2015, a period of at least ten years

following redesignation to attainment by EPA. The Maintenance Plan also contains

contingency measures that have been implemented and describes the process and

schedule that will be used to consider additional measures, if needed. Contingency

provisions will be triggered when the three-year average of the fourth highest daily

maximum hourly measurement exceeds 0.120 ppm at any ozone monitor.
2-1

CHAPTER TWO

REDESIGNATION REQUEST

The Maricopa Association of Governments (MAG) requests that the U.S. Environmental

Protection Agency (EPA) redesignate the Maricopa County nonattainment area to

attainment for the one-hour ozone National Ambient Air Quality Standard. The area was

designated a one-hour ozone nonattainment area in 1978, but has not violated the

standard since 1996. Therefore, the area is eligible for redesignation.

REQUIRED COMPONENTS OF A REDESIGNATION REQUEST

The EPA Administrator may not redesignate an area to attainment, unless the following

requirements of Section 107(d)(3)(E) of the Clean Air Act (CAA) are met. These four

requirements for redesignation are discussed in this chapter.

1. The Administrator determines that the area has attained the national ambient air

quality standards.

2. The Administrator has fully approved the applicable implementation plan under

Section 110(k).

3. The Administrator determines that the improvement in air quality is due to

permanent and enforceable reductions in emissions.

4. The State has met all applicable requirements under Section 110 and Part D.

A fifth requirement for redesignation to attainment is that:

5. The EPA Administrator approve a maintenance plan for the area that meets the

provisions of Section 175A.

Chapter Three contains the maintenance plan that is being submitted to EPA to fulfill this

fifth and final requirement.

ATTAINMENT OF THE ONE-HOUR OZONE STANDARD

On May 30, 2001, the Environmental Protection Agency determined that the Maricopa

serious ozone nonattainment area had attained the one-hour standard. The attainment

determination was effective June 29, 2001.

Attainment of the one-hour ozone National Ambient Air Quality Standard is demonstrated

when three consecutive years of monitoring data for each site average no more than one

exceedance per year. The following information demonstrates, as required by Section

107(d)(3)(E) of the Clean Air Act, that the Maricopa County nonattainment area has
2-2

attained the one-hour ozone national air quality standard. This is based on quality assured

monitoring data representing all monitoring locations in the nonattainment area.

Historical Perspective

A review of one-hour ozone monitoring data since 1994 reveals that in 1994 through 1996,

there were a total of 18 exceedance days, six in 1994, eleven in 1995, and one in 1996.

Data from the regional monitoring network indicates that the Maricopa County

nonattainment area last exceeded the one-hour ozone standard in 1996. There were no

exceedances of the standard at any site during the period 1997-2002.

The Maricopa County nonattainment area typically experiences hot conditions during the

summer months between May and September with daytime temperatures exceeding 90

degrees Fahrenheit. Although seasonal rainfall may occur during this period, dry

conditions usually persist with clear skies making the region conducive to ozone formation.

Wind speeds during the summer are frequently less than five miles per hour. The

differences in topography between the mountainous areas and valley floor create uneven

heating and cooling which influence air flow patterns. The wind patterns generally exhibit

an easterly direction in the morning and shift to a westerly direction in the afternoon.

These wind patterns generally tend to disperse precursor emissions to the east and north

of the urban area. A detailed description of the climate conditions and local wind patterns

is included in the Final Serious Area Ozone State Implementation Plan for Maricopa

County on pages 1-1 through 1-3.

Ozone Monitoring Network

The ambient air monitoring network for ozone in the Maricopa County nonattainment area

consists of four National Air Monitoring Stations (NAMS), 14 State and Local Air Monitoring

Stations (SLAMS), and three Special Purpose Monitors (SPM) operated by the Maricopa

County Environmental Services Department and the Arizona Department of Environmental

Quality. The ozone monitoring sites are identified, along with summary data from 2000

through 2002, in Tables 2-1 through 2-3. Figure 2-1 shows the geographical distribution

of the regional monitoring network.

Monitoring Results and Attainment of the Standard

The monitoring data presented in Tables 2-1 through 2-3 verify that the Maricopa County

nonattainment area has been in attainment for the national one-hour ozone standard since

1997, as well as for the most recent three-year period (2000-2002), in accordance with the

federal requirements of 40 CFR 50.9. Data recovery rates for most monitors within the

monitoring network exceed the 75 percent completeness requirements for the three-year

period. In addition, all state and federal quality assurance procedures have been followed.

Figure 2-2 illustrates the downward trend for monitors in the nonattainment area with the

fourth-highest one-hour ozone concentrations.
TABLE 2-1

2000 OZONE MONITORING DATA SUMMARY FOR

THE MARICOPA COUNTY NONATTAINMENT AREA

1-HOUR STANDARD: .12 PPM*

2-3

Site Max Value

(PPM)

2

nd High

(PPM)

3

rd High

(PPM)

4

th High

(PPM)

Blue Point, Usery Pass & Bush Hwy .108 .107 .101 .101

Central Phoenix, 1845 E. Roosevelt .094 .092 .091 .091

Emergency Mgt., 2035 N. 52nd St.S.088 .085 .084 .083

Falcon Field, 4530 E. McKellips, .097 .093 .092 .090

Fountain Hills, 16426 E. Palisades .117 .106 .101 .097

Glendale, 6000 W. OliveS

.100 .094 .090 .089

Humboldt Mt., Top of Humboldt Mt.S

.093 .093 .092 .091

# JLG Supersite, 4530 N. 17th Ave. .104 .090 .089 .085

Lake Pleasant, 41402 N. 17th Ave.S

.097 .092 .091 .091

Maryvale, 6180 W. EncantoS.100 .096 .093 .092

Mesa, 370 S. Brooks .102 .090 .087 .083

Mount Ord, Mazatzal Mountains .111 .109 .106 .105

North Phoenix, 601 E. Butler .107 .107 .098 .096

Palo Verde, 36248 W. Elliot Rd. .103 .091 .087 .085

Pinnacle Peak, 25000 N. Windy Walk .117 .104 .100 .097

Rio Verde, 25608 N. Forest Rd.S.117 .108 .107 .105

South Phoenix, 33 W. Tamarisk .102 .094 .093 .092

South Scottsdale, 2857 N. Miller .099 .097 .097 .096

# Tempe, Apache Blvd. & College Ave. .099 .094 .090 .090

# West Chandler, 163 S PriceS.083 .083 .082 .079

# West Chandler, Frye Rd. & EllisS

.100 .099 .091 .090

West Phoenix, 3847 W. Earll .099 .098 .097 .092

* Due to mathematical rounding, values $ .125 ppm are necessary to exceed the standard.

# Indicates < 75% data available.

S

 Seasonal monitor operating from April 1 to November 1.
TABLE 2-2

2001 OZONE MONITORING DATA SUMMARY FOR

THE MARICOPA COUNTY NONATTAINMENT AREA

1-HOUR STANDARD: .12 PPM*

2-4

Site Max Value

(PPM)

2

nd High

(PPM)

3

rd High

(PPM)

4

th High

(PPM)

Blue Point, Usery Pass & Bush Hwy .111 .104 .093 .093

# Cave Creek, 37109 N. Lava LaneS.112 .100 .096 .092

Central Phoenix, 1845 E. Roosevelt .091 .091 .090 .090

# Emergency Mgt., 2035 N. 52nd St.S

.073 .072 .072 .072

Falcon Field, 4530 E. McKellips, .111 .100 .097 .095

Fountain Hills, 16426 E. Palisades .110 .106 .098 .097

Glendale, 6000 W. OliveS

.116 .099 .098 .098

Humboldt Mt., Top of Humboldt Mt.S.098 .096 .096 .096

JLG Supersite, 4530 N. 17th Ave. .101 .095 .094 .093

# Lake Pleasant, 41402 N. 87th Ave.S.085 .083 .082 .080

Maryvale, 6180 W. EncantoS

.097 .091 .089 .088

Mesa, 370 S. Brooks .093 .092 .088 .084

Mount Ord, Mazatzal MountainsS.102 .089 .089 .089

North Phoenix, 601 E. Butler .110 .101 .098 .097

Palo Verde, 36248 W. Elliot Rd.S.085 .085 .083 .081

Pinnacle Peak, 25000 N. Windy Walk .107 .103 .102 .100

Rio Verde, 25608 N. Forest Rd.S

.102 .100 .099 .096

South Phoenix, 33 W. Tamarisk .098 .094 .092 .086

South Scottsdale, 2857 N. Miller .102 .101 .094 .092

# Surprise, 18600 N. Reems .093 .088 .087 .083

Tempe, Apache Blvd. & College Ave. .099 .099 .096 .093

West Chandler, Frye Rd. & Ellis S

.105 .100 .096 .092

West Phoenix, 3847 W. Earll .099 .094 .094 .089

* Due to mathematical rounding, values $ .125 ppm are necessary to exceed the standard.

# Indicates < 75% data available.

S

 Seasonal monitor operating from April 1 to November 1.
TABLE 2-3

2002 OZONE MONITORING DATA SUMMARY FOR

THE MARICOPA COUNTY NONATTAINMENT AREA

1-HOUR STANDARD: .12 PPM*

2-5

Site Max Value

(PPM)

2

nd High

(PPM)

3

rd High

(PPM)

4

th High

(PPM)

Blue Point, Usery Pass & Bush Hwy .110 .104 .102 .098

Cave Creek, 37109 N. Lava LaneS.102 .100 .099 .096

Central Phoenix, 1845 E. Roosevelt .123 .098 .089 .089

Falcon Field, 4530 E. McKellips, .113 .111 .101 .098

Fountain Hills, 16426 E. Palisades .114 .107 .105 .101

Glendale, 6000 W. OliveS

.101 .099 .097 .090

Humboldt Mt., Top of Humboldt Mt.S

.124 .099 .098 .096

JLG Supersite, 4530 N. 17th Ave. .117 .110 .094 .088

Maryvale, 6180 W. EncantoS

.119 .111 .108 .094

Mesa, 370 S. Brooks .097 .091 .083 .083

North Phoenix, 601 E. Butler .111 .104 .104 .100

Palo Verde, 36248 W. Elliot Rd.S.092 .090 .085 .085

Pinnacle Peak, 25000 N. Windy Walk .115 .102 .101 .101

Rio Verde, 25608 N. Forest Rd.S.101 .100 .099 .099

South Phoenix, 33 W. Tamarisk .104 .104 .091 .089

South Scottsdale, 2857 N. Miller .102 .094 .093 .092

Surprise, 18600 N. Reems .098 .091 .086 .086

Tempe, Apache Blvd. & College Ave. .100 .097 .096 .096

# Tonto National Monument, 

Maintenance StationS

.111 .107 .102 .097

West Chandler, Frye Rd. & EllisS.110 .101 .097 .096

West Phoenix, 3847 W. Earll .123 .116 .097 .095

* Due to mathematical rounding, values $ .125 ppm are necessary to exceed the standard.

# Indicates < 75% data available.

S

 Seasonal monitor operating from April 1 to November 1.












	








	 


















	



 

	







	



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2-7
2-8

Quality Assurance Program

One-hour ozone data for the Maricopa County area has been collected and quality-assured

in accordance with 40 CFR, Part 58, Appendix A, EPA’s “Quality Assurance Handbook for

Air Pollution Measurement Systems, Volume II; Ambient Air Specific Methods”, the

Maricopa County Ambient Air Monitoring Program QA/QC Procedures, and the Arizona

Department of Environmental Quality (ADEQ) Quality Assurance Project Plan. The data

are recorded in the EPA Aerometric Information Retrieval System (AIRS) and are also

available for public review in air quality monitoring reports produced annually by the

Maricopa County Environmental Services Department and the Arizona Department of

Environmental Quality.

APPROVAL OF THE OZONE NONATTAINMENT SIP ELEMENT FOR THE MARICOPA

COUNTY AREA

In accordance with the 1990 Clean Air Act Amendments, the Maricopa County

nonattainment area was initially classified as Moderate for ozone. In order to meet the

Moderate area requirements, the MAG 1993 Ozone Plan was submitted to the

Environmental Protection Agency by November 15, 1993. An Addendum to this Plan was

submitted in March 1994. On November 6, 1997, the nonattainment area was reclassified

to Serious due to failure to attain the one-hour ozone standard by November 15, 1996.

The Serious Area reclassification was effective on February 13, 1998.

On December 14, 2000, the Arizona Department of Environmental Quality submitted the

Final Serious Area Ozone State Implementation Plan for Maricopa County to EPA. In

accordance with Section 110, a completeness finding on the Final Serious Area Ozone

State Implementation Plan was deemed by operation of law since a determination was not

made by EPA within six months of receipt of the Plan.

While this latest SIP has not been approved under Section 110(k), it is anticipated that

EPA may approve the Final Serious Area Ozone Plan before this request for redesignation

is submitted. If not, approval action on SIP elements of the Revised Serious Area Ozone

Plan and the redesignation request can occur simultaneously.

IMPROVEMENT IN AIR QUALITY DUE TO PERMANENT AND ENFORCEABLE

EMISSION REDUCTIONS

This section is intended to demonstrate that the improved air quality in the Maricopa

County nonattainment area has occurred as a result of permanent and enforceable

emissions reductions. The monitoring data clearly indicate that ozone concentrations have

declined steadily since 1994. This continuous decline in emissions and concentrations has

occurred during a period when the area has experienced more than a 25 percent increase

in population, employment, and vehicle miles of travel.

According to the EPA memorandum, Procedures for Processing Requests to Redesignate

Areas to Attainment, September 4, 1992, “The state must be able to reasonably attribute
2-9

the improvement in air quality to emission reductions which are permanent and

enforceable.” As Figure 2-2 illustrates, there has been a continuous downward trend in

ozone concentrations at all monitors in the nonattainment area. The fourth-highest ozone

levels decreased by 17 percent between 1995 and 2002, at the same time population,

employment and vehicle travel in the nonattainment area increased by about 30 percent.

Over time, several control measures have been implemented in the Maricopa County

nonattainment area which have resulted in the decline in ozone concentrations. For

example, the Environmental Protection Agency published a final rule on May 27, 1998

determining that the Maricopa nonattainment area has in place sufficient control measures

to meet the 15 percent rate of progress requirement in the Clean Air Act. The Final

Serious Area Ozone State Implementation Plan submitted in December 2000 also included

Reasonably Available Control Technology (RACT) requirements for sources subject to

RACT under the Clean Air Act. 

In addition, the Revised MAG 1999 Serious Area Carbon Monoxide Plan and MAG Carbon

Monoxide Redesignation Request and Maintenance Plan include measures which also

reduce ozone. Many of these measures have been included in this Ozone Maintenance

Plan.

The Maintenance Plan described in the next chapter models the year 2015. Table VI-2 in

the One-Hour Maintenance Plan Technical Support Document summarizes the emission

reductions attributable to control measures in 2015. The next section describes the control

measures for which numeric emission reduction credit was assumed in order to maintain

the one-hour ozone standard through 2015.

ATTAINMENT AND MAINTENANCE CONTROL MEASURES

Generally, the overall approach taken in preparing the One-Hour Ozone Maintenance Plan

is to demonstrate maintenance of the one-hour ozone standard in 2015 with the committed

measures in the Revised MAG 1999 Serious Area Carbon Monoxide Plan and Carbon

Monoxide Redesignation Request and Maintenance Plan, since most of those measures

also reduce ozone. Therefore, the Ozone Maintenance Plan relies heavily upon the

Revised MAG Serious Area Carbon Monoxide Plan and its supporting documents,

including the commitments to implement control measures. The Ozone Maintenance Plan

also relies upon the Final Serious Area Ozone State Implementation Plan for Maricopa

County and the modified Arizona Cleaner Burning Gasoline Program. 

Detailed descriptions of the measures are contained in Chapter Eight of the Revised

Serious Area Carbon Monoxide Plan, (fifty-five measures) Chapters Two and Three of the

Carbon Monoxide Maintenance Plan, and Chapter Two of the Final Serious Area Ozone

SIP for Maricopa County. The committed measures used for numeric emission reduction

credit in the Ozone Maintenance Plan for 2015 are described below. These measures,

which are permanent and enforceable, are anticipated to be in place through the

maintenance year of 2015. Continued implementation of these measures, as well as the
2-10

other measures in the aforementioned plans, willensure continuing reductions in emissions

through 2015 and beyond.

1. Summer Fuel Reformulation: California Phase 2 andFederal Phase II Reformulated

Gasoline with 7 psi from May 1 through September 30 

The Arizona Legislature passed H.B. 2307 in 1997 which contains requirements for the

sale of gasoline from and after May 1, 1999 in Area A, subject to an appropriate waiver

granted under Section 211 (c) (4) of the Clean Air Act, that meets the following fuel

reformulation options:

• California Phase 2 Reformulated Gasoline, including alternative formulations

allowed by the predictive model, as adopted by the California Air Resources

Board pursuant to the California Code of Regulations, Title 13, Sections

2261 through 2262.7 and 2265, in effect on January 1, 1997, that meets the

maximum 7.0 psi summertime vapor pressure requirements in A.R.S.

Section 41-2083, Subsections D and F.

• Gasoline that meets the standards for Federal Phase II Reformulated

Gasoline, as provided in 40 CFR Section 80.41, paragraphs (a) through (h),

in effect on January 1, 1997, that meets the maximum 7.0 psi summertime

vapor pressure requirement in A.R.S. Section 41-2083 Subsections D and

F.

On February 10, 1998, the Environmental Protection Agency approved Arizona’s cleaner

burning gasoline (CBG) program into the State Implementation Plan. The program was

implemented in two stages - from June to September 1998, gasoline sold in the area had

to meet the standards similar to Federal Phase I Reformulated Gasoline or California’s

Phase 2 Reformulated Gasoline. Then, beginning May 1, 1999, all gas sold in the area

had to meet standards similar to Federal Phase II or California’s Phase 2 Reformulated

Gasoline.

Arizona’s CBG Program was included in the 1998 metropolitan Phoenix Ozone 15 Percent

Rate of Progress Federal Implementation Plan as a committed control measure for

emissions reduction credit. On July 6, 1999, EPA finalized a rule revising the federal plan

as it related to the CBG Program.

On April 28, 2000, Senate Bill 1504 was signed into law by the Governor of Arizona. The

law revised A.R.S. Section 41-2124 by eliminating the maximum oxygenate requirement

for summertime gasoline in Maricopa County. Because of the cost and difficulty of

blending ethanol in CBG and meeting the 7.0 psi Reid Vapor Pressure standard, MTBE

has been the primary oxygenate used in Arizona’s summertime CBG.

On September 29, 2003, the Environmental Protection Agency published a notice

proposing to approve revisions to the Arizona Clean Burning Gasoline Program currently

approved in the State Implementation Plan. The revisions replace Arizona’s interim CBG
2-11

program with a permanent program, amend the wintertime CBG program to limit the types

of gasoline that may be supplied, and remove the minimum oxygen requirement for

summertime gasoline. On January 26, 2004, the EPA Administrator signed the final

approval notice for the revisions to the Arizona Clean Burning Gasoline Program. The final

notice was published in the Federal Register on March 4, 2004, effective on April 5, 2004.

This measure is a committed measure in the State Implementation Plan for ozone and a

committed maintenance measure in the Ozone Maintenance Plan. This measure accounts

for a 1.8 percent reduction in NOx emissions and 0.6 percent reduction in VOC emissions

in 2015. Additional information on this measure can be found in the One-Hour Ozone

Maintenance Plan Technical Support Document on page VI-6.

2. Phased-In Emission Test Cutpoints

The Arizona Vehicle Inspection Maintenance Program was established in 1976 to promote

the clean operation of motor vehicles by controlling vehicle exhaust emissions. The

program is operated by the Arizona Department of Environmental Quality and contains the

provisions listed in Section 182(c)(3) of the Clean Air Act for an Enhanced Vehicle

Inspection and Maintenance Program. 

The Vehicle Emissions Inspection Maintenance Program was significantly enhanced and

strengthened by the Arizona Legislature in 1993 (H.B. 2001). The Legislature established

a biennial, transient loaded (I/M 240) emissions test for gasoline powered vehicles model

year 1981 or newer with a gross vehicle weight of up to 8,500 pounds, beginning

January 1, 1995. 

In 1993, the Arizona Legislature passed H.B. 2001 which increased the repair threshold

limits for gasoline powered vehicles in order to be eligible for a waiver through the Vehicle

Emissions Inspection Maintenance Program. The repair limits were increased in the

following manner: 1967-1974 from $50 to $100; 1975-1980 from $200 to $300; and 1981

and newer from $300 to $450. The bill also increased the repair threshold limits from $300

to $500 for diesel powered vehicles with tandem axles or a gross vehicle weight in excess

of 26,000 pounds.

The Arizona Legislature passed H.B. 2237 in 1997 which contained an appropriation of

$120,000 from the State General Fund to the Arizona Department of Environmental Quality

to develop and implement an alternative test protocol to reduce the false failure rates

associated with the more stringent pass-fail standards for the Vehicle Emissions Testing

Program (Section 19 of H.B. 2237).

In addition, the Arizona Department of Environmental Quality was to implement Interim

Test Cutpoints for the Vehicle Emissions Inspection Program until issues were resolved

with the final test cutpoints for the I/M 240 Program. The Interim Cutpoints were selected

to achieve the following failure rates in three vehicle class categories (Light Duty Gasoline

Vehicles, Light Duty Gasoline Trucks 1, and Light Duty Gasoline Trucks 2: 50 percent for

Model Years 1981-85; 25 percent for 1986 to 1989 model years, and 10 percent for Model

Years 1990-93). 
2-12

In August 2002, EPA proposed approval of the Arizona I/M Program and signed the final

approval notice on October 31, 2002. The final approval notice was published in the

Federal Register on January 22, 2003. This measure is a committed attainment measure

in the Revised Serious Area Carbon Monoxide Plan, a committed maintenance measure

in the Carbon Monoxide Maintenance Plan, and a committed maintenance measure in the

One-Hour Ozone Maintenance Plan. This measure is estimated to provide less than 0.1

percent increase in NOx

 emissions and less than a 0.1 percent reduction in VOC

emissions, in 2015. Additional information on this measure can be found in the Revised

Serious Area Carbon Monoxide Plan on page 8-5, Carbon Monoxide Maintenance Plan

TSD on page VII-10, and the One-Hour Ozone Maintenance Plan Technical Support

Document on page VI-11.

3. One-Time Waiver from Vehicle Emissions Test

The Arizona Legislature passed S.B. 1002 in 1996 which limits the issuance of a waiver

for failure to comply with the emission testing requirements to one-time only beginning

January 1, 1997 (A.R.S. 49-542 D). This measure is a committed attainment measure in

the Revised Serious Area Carbon Monoxide Plan, a committed maintenance measure in

the Carbon Monoxide Maintenance Plan, and a committed measure in the One-Hour

Ozone Maintenance Plan. This measure is estimated to provide a less than 0.1 percent

reduction in NOX emissions and less than a 0.1 percent reduction in VOC emissions, in

2015. Additional information on this measure can be found in the Revised Serious Area

Carbon Monoxide Plan on page 8-10, Carbon Monoxide Maintenance Plan Technical

Support Document on page VII-11, and the One-Hour Ozone Maintenance Plan Technical

Support Document on page VI-12.

4. Coordinate Traffic Signal Systems

The Arizona Legislature passed H.B. 2001 in 1993 which required that Maricopa County

and the cities and towns in the vehicle emissions control area (Maricopa County

nonattainment area) synchronize traffic control signals on all roadways, within and across

jurisdictional boundaries, which have a traffic flow exceeding 15,000 motor vehicles per

day.

The synchronization of existing signals, as well as the enhancement of coordination among

signal systems that are already synchronized, has been identified by many jurisdictions

through a number of programs. Enhancement efforts range from large scale programs

covering broad geographic areas to incremental additions of a few synchronized signals

to the network. This includes both individual city projects and regional programs, such as

AZTech, also mentioned below. 

This measure is a committed attainment measure in the Revised Serious Area Carbon

Monoxide Plan, a committed maintenance measure in the Carbon Monoxide Maintenance

Plan, and a committed maintenance measure in the One-Hour Ozone Maintenance Plan.

This measure is estimated to provide less than 0.1 percent reduction in NOx

 emissions and

a 0.1 percent reduction in VOC emissions, in 2015. Additional information on this measure

can be found in the Revised Serious Area Carbon Monoxide Plan on page 8-88, Carbon
2-13

Monoxide Maintenance Plan TSD, on page VII-13, and the One-Hour Ozone Maintenance

Plan Technical Support Document on page VI-13.

5. Develop Intelligent Transportation Systems

Many local jurisdictions have begun planning and implementing advanced technology

based solutions to address complex traffic management issues on the regional

transportation network. These technologies involve the application of electronics,

telecommunications and sensor technologies and are collectively referred to as Intelligent

Transportation Systems (ITS).

A key component of the regional Intelligent Transportation Infrastructure is the Freeway

Management System (FMS) operated by the Arizona Department of Transportation

(ADOT). The FMS currently covers 42 miles of the freeway system and provides services

such as traveler advisories and incident management. The other major regional ITS

initiative is the AZTech project. This project was selected and funded by USDOT to serve

as one of four ITS Model Deployment Initiatives in the nation. Key elements of the AZTech

project are the interconnection of 13 local traffic management centers and the

instrumentation of eight “smart” corridors that cover nearly 150 miles of arterial streets. 

This measure is a committed attainment measure in the Revised CarbonMonoxide Serious

Area Carbon Monoxide Plan, a committed maintenance measure in the Carbon Monoxide

Maintenance Plan, and a committed measure in the One-Hour Ozone Maintenance Plan.

This measure accounts for a less than 0.1 percent increase in NOx emissions and less than

0.1 percent reduction in VOC emissions, in 2015. Additional information on this measure

can be found in the Revised Serious Area Carbon Monoxide Plan on page 8-31, Carbon

Monoxide Maintenance Plan TSD on page VII-14, and One-Hour Ozone Maintenance Plan

Technical Support Document on page VI-14.

6. Tougher Enforcement of Vehicle Registration and Emissions Test Compliance

The Motor Vehicle Division (MVD) of the Arizona Department of Transportation (ADOT)

has instituted a comprehensive vehicle registration enforcement program. Three key

elements of the new program are a Registration Enforcement Team, a Registration

Enforcement Tracking System, and a New Resident Tracking Program. Through public

participation, consistent policy and procedure application, and new tracking methods, MVD

will enforce the Arizona registration laws to ensure vehicles in question are registered

properly. This will be an ongoing effort.

Another phase of the Program is an initiative to coordinate ADOT efforts with other law

enforcement agencies toassist MVDpersonnel in enforcing registration compliance. Other

initiatives include a system user agreement between MVD and the City Courts to utilize

information in conjunction with registration compliance and discussions with U.S. West

(now known as Qwest) for obtaining information relating to new connect customers.

The Arizona Legislature passed S.B. 1427 in 1998 which requires school districts and

special districts in Area A to prohibit parking in employee parking lots by employees who
2-14

have not complied with emissions testing requirements. Cities, towns, and counties in

Area A and Area B are currently subject to this provision (A.R.S. 49-552).

In 1999, the Arizona Legislature passed H.B. 2254 which requires each vehicle that is

owned by the United States government and that is domiciled in this state for more than

ninety consecutive days and each vehicle that is owned by a state or political subdivision

of this state to comply with A.R.S. 49-542. 

Collectively, the provisions in H.B. 2254 that apply to Tougher Enforcement of Vehicle

Registration and Emissions Test Compliance include A.R.S. 49-557 and 49-541.01 D.

and E.

This measure is a committed contingency measure in the Revised Serious Area Carbon

Monoxide Plan, a committed maintenance measure in the Carbon Monoxide Maintenance

Plan and a committed measure in the One-Hour Ozone Maintenance Plan. This measure

accounts for a 0.1 percent reduction in NOx emissions and a 0.1 percent reduction in VOC

emissions in 2015. Additional information on this measure can be found in the Revised

Serious Area Carbon Monoxide Plan on page 8-13, Carbon Monoxide Maintenance Plan

Technical Support Document on page VII-15, and One-Hour Maintenance Plan Technical

Support Document on page VI-16.

7. Maricopa County Rule 348: Aerospace Manufacturing and Rework Operations

Maricopa County adopted Rule 348 on April 4, 1999 to implement reasonably available

control technology (RACT) for aerospace manufacturing and rework operations. The rule

was approved into the State Implementation Plan effective November 19, 1999 (see 64 FR

50759). The purpose of the rule is to limit the emissions of volatile organic compounds

from the manufacture and rework of aerospace vehicles and their components. Some of

the vehicles included in Rule 348 are airplanes, helicopters, missiles, rockets and space

vehicles.

The SIP approved measure is a RACT measure in the Final Serious Area Ozone State

Implementation Plan for Maricopa County and a RACT and committed measure in the

One-Hour Ozone Maintenance Plan. Rule 348 has a control efficiency of 3 percent and

a rule effectiveness of 80 percent for SCC codes 31399999, 39999999, 40200701,

40100901, 40203001, 40299999, 40400213, and 40799999. This measure accounts for

a less than 0.1 percent reduction in VOC emissions. There is no expected effect on NOx

emissions. Additional information on this measure can be found in the Final Serious Area

Ozone SIP on page 2-4 and the One-Hour Ozone Maintenance Plan Technical Support

Document on page VI-17. 

CLEAN AIR ACT SECTION 110 AND PART D REQUIREMENTS

Before an area can be redesignated to attainment, it must meet the requirements of

Section 110 and Part D of the Clean Air Act. The provisions of Section 110(a)(2) and Part

D are required as part of the State Implementation Plan to bring the Maricopa County

nonattainment area into attainment, and have been addressed in plan submissions
2-15

currently under review by EPA. EPA has indicated that they expect to approve the Revised

MAG 1999 Serious Area Carbon Monoxide Plan for the Maricopa County Nonattainment

Area in 2003, which includes several of the same measures relied upon for the One-Hour

Ozone Maintenance Plan. It is also anticipated that EPA will approve the Carbon

Monoxide Redesignation Request and Maintenance Plan and the Final Serious Area

Ozone State Implementation Plan for Maricopa County in the near future. Upon approval

of the plans, EPA will have determined that all applicable provisions of Section 110 and

Part D have been met. The following section lists the applicable requirements of Section

110 and Part D and provides references from the Revised Serious Area Carbon Monoxide

Plan, Carbon Monoxide Maintenance Plan, and Final Serious Area Ozone Plan that

address those requirements.

Section 110(a)(2) addresses general requirements for State Implementation Plans. The

following discussion indicates how each of these requirements is addressed in the Revised

Serious Area Carbon Monoxide Plan and other plans as appropriate. The numbers in

parentheses indicate the subsection of the following narrative in which each of the Section

110(a)(2) requirements is addressed below.

(A) Include enforceable measures and schedules necessary to show compliance. (1)

2. Monitor and compile data on ambient air quality. (2)

3. Provide a program to enforce measures in (A) and regulate stationary sources.

(1),(4)

(D) Prohibit sources from emitting pollutants that would contribute significantly to

nonattainment, interfere with maintenance of the standard, or interfere with

Prevention of Significant Deterioration (PSD) or visibility in other states. (3)

5. Provide assurances that there are adequate resources to implement the plan,

nothing in the SIP is otherwise prohibited by law, and the State has responsibility

for ensuring adequate implementation. (1)

6. Stationary source emissions monitoring and reporting. (4)

7. Provide for emergency powers authority. (5)

8. Provide for the revisions to the plan. (6)

9. Meet the applicable requirements of Part D for nonattainment areas. (10)

10. Meet the requirements of Section 121 (consultation). (9);Section 127 (public

notification);(7) and part C (PSD and visibility). (3),(4)

11. Perform air quality modeling. (8)

12. Permitting fees for major stationary sources. (4)

13. Consultation and participation by local political subdivisions affected by the SIP. (9)

(1) Enforcement, Adequate Resources, and Responsibility for Adequate

Implementation

Sections 110(a)(2)(A), (C) and (E) concerning plan enforcement and implementation

requirements are addressed in Chapter Eight (page 8-146) and Chapter Eleven (page 11-

1) of the Revised Serious Area Carbon Monoxide Plan. In order to comply with these

sections, a State law was passed in 1992 which provides an approach for assurances that
2-16

State and local committed measures will be adequately implemented (A.R.S. Section 49-

406 I. and J.).

Regarding committed measures, A.R.S. Section 49-406 G. (passed by the Legislature in

1992) requires that each agency which commits to implement any control measure

contained in the State Implementation Plan must describe the commitment in a resolution.

The resolution must be adopted by the appropriate governing body of the agency. State

law also requires the entity to specify the following information in the resolutions: (1) its

authority for implementing the limitation or measure as provided in statute, ordinance, or

rule; (2) a program for the enforcement of the limitation or measure; and (3) the level of

personnel and funding allocated to the implementation of the measure.

Chapter Eleven of the Revised Serious Area Carbon Monoxide Plan includes resolutions

from the MAG member agencies and other implementing entities. The resolutions indicate

specific commitments to implement various control strategies. Generally, the authorities

of cities and towns to implement the types of measures that they have committed to in their

respective resolutions are provided under A.R.S. § 9-240 Powers of Common Council.

The general authorities of the County to implement the measures in the commitments are

provided under A.R.S. § 11-251 and A.R.S. § 49-478. Copies of these local and county

government authorities are included in Chapter Eleven of the Revised Serious Area

Carbon Monoxide Plan.

If any person (includes State, County, local governments, regional agencies, and other

entities) fails to implement a committed measure, the County would file an action in

Superior Court to have the Court order that the measure be implemented. Likewise, the

Director of the Arizona Department of Environmental Quality will backstop the County if it

fails to implement a committed measure or if the County fails to backstop the local

governments and regional agencies (see Appendix C, Exhibit 2, Revised Serious Area

Carbon Monoxide Plan).

(2) Monitoring and Compiling of Data on Ambient Air Quality

Section 110(a)(2)(B) establishes the requirement to monitor, compile, and analyze ambient

air quality data. Appendix A, Exhibit 2 of the Revised 1999 Serious Area Carbon Monoxide

Plan contains the 1992 Memorandum of Agreement for Air Quality Planning. This

agreement identifies Maricopa County and the Arizona Department of Environmental

Quality as having the primary roles for air quality monitoring, including special purpose air

quality and meteorological monitoring for plan development.

Chapter Four of the Revised Serious Area Carbon Monoxide Plan (page 4-5) provides

additional evidence that the monitoring requirements for the region are being met through

the efforts of the Maricopa County Environmental Services Department and the Arizona

Department of Environmental Quality. Arizona Statutes 49-406. Nonattainment area plan

and 49-424. Duties of Department provide the regulatory basis for air quality monitoring in

the State and any nonattainment areas. Additional information on the current ambient air
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quality monitoring network operated in the Maricopa nonattainment area is detailed earlier

in this chapter.

(3) Provisions to Prohibit Sources from Impacting Air Quality in Other States

Section 110(a)(2)(D) requires that a SIP contain adequate provisions prohibiting any

source or other type of emissions activity within the State from emitting any air pollutant in

amounts which will contribute significantly to nonattainment in, or interfere with

maintenance by, any other State with respect to any such national primary or secondary

ambient air quality standard; or interfere with measures required to be included in the

applicable implementation plan for any other State under Part C to prevent significant

deterioration of air quality or to protect visibility.

Visibility, as defined in Part C of the Clean Air Act, is currently addressed through a Federal

Implementation Plan for the State of Arizona. The lack of proximity to another state makes

it unlikely that ozone emissions are transported from the nonattainment area to another

state. 

4. Preconstruction Review for All New and Modified Stationary Sources; Stationary

Source Emissions Monitoring; and Permitting Fees for Major Stationary Sources

The requirements of Sections 110(a)(2)(C), (F), and (L) concerning preconstruction review,

emissions monitoring, and permitting fees for stationary sources are addressed by the

State in Title 49. Article 2. State Air Pollution Control, and Article 3. County Air Pollution

Control, of the Arizona Revised Statutes. Compliance with this requirement is the

responsibility of the Arizona Department of Environmental Quality or applicable county

agency. Appendix A, Exhibit 2 of the Revised Plan contains the 1992 Memorandum of

Agreement for Air Quality Planning. This agreement identifies Maricopa County as having

the lead role for stationary source emissions control.

Following adoption by the State, Maricopa County adopted new source review regulations

designed to prevent significant deterioration of air quality, patterned after the State

regulations. The Maricopa County Regulations contain requirements for obtaining

installation permits for new major sources located in nonattainment, attainment, or

unclassifiable areas. Both the State and Maricopa County new source review regulations

are currently in effect.

The Maricopa County Air Pollution Control Regulations contain the regulations that

constitute the legal basis for control of air pollution sources in Maricopa County, Arizona.

They are adopted to implement the policy set forth in Title 49 of the Arizona Revised

Statutes and to fulfill the State’s responsibilities under the Federal Clean Air Act and its

amendments to provide a legally enforceable State Implementation Plan for the attainment

and maintenance of the National Ambient Air Quality Standards.

Applicable Maricopa County Air Pollution Control Regulations include; Rule 240 - Permits

for New Major Sources and Major Modifications to Existing Major Sources, Rule 241 -
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Permits for New Sources and Modifications to Existing Major Sources, and Rule 245 -

Continuous Source Emission Monitoring.

(5) Provide for Authority Comparable to that in Section 303 for Emergency Powers

Section 110(a)(2)(G) addresses the authority for emergency powers. Under Section 303

of the Clean Air Act, upon receipt of evidence that a pollution source or combination of

sources (including moving sources) is presenting an imminent and substantial

endangerment to public health or welfare, or the environment, the EPA Administrator may

bring suit on behalf of the United States in the appropriate United States district court to

immediately restrain any person causing or contributing to the alleged pollution to stop the

emission of air pollutants causing or contributing to such pollution or to take such other

action as may be necessary. If it is not practicable to assure prompt protection of public

health or welfare or the environment by commencement of such a civil action, the

Administrator may issue such orders as may be necessary to protect public health or

welfare or the environment.

Emergency powers for the State of Arizona are addressed under A.R.S. 49-465. Imminent

and substantial endangerment, 49-462.07 Violation; injunctive relief, and 49-465 Air

Pollution Emergency.

(6) Provide for Plan Revisions to Account for Changes to the NAAQS or When a Plan

is Found Substantially Inadequate to Attain a Standard

Section 110(a)(2)(H) requires a plan revision to take account of revisions of such national

primary or secondary ambient air quality standard, or the availability of improved or more

expeditious methods of attaining such standard, and whenever the Administrator finds that

the plan is substantially inadequate to attain the national ambient air quality standard. 

A.R.S. 49-404 State Implementation Plan and 49-406 Nonattainment Area Plan provisions

provide for State, county, and local agencies to revise the SIP to account for changes to

air quality standards or if a plan is found to be inadequate. The applicable documentation

for making plan revisions can be found in the Revised 1999 Serious Area Caron Monoxide

Plan, Appendix A, Exhibit 2, 1992 Memorandum of Agreement for Air Quality Planning.

(7) Meet the Applicable Requirements of Section 127 (Relating to Public Notification)

Section 110(a)(2)(J) requires a plan revision to meet the applicable requirements of

Section 127 relating to Public Notification. Public notification procedures followed for the

Revised Serious Area Carbon Monoxide Plan are documented in the section, Public

Participation in the Preparation of the MAG 1999 Serious Area Carbon Monoxide Plan and

MAG 1999 Serious Area PM-10 Plan, in Chapter Ten (page 10-3).
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(8) Air Quality Modeling

Section 110(a)(2)(K) provides for the performance of such air quality modeling as the

Administrator may prescribe for the purpose of predicting the effect on ambient air quality

of any emissions of any air pollutant for which the Administrator has established a national

ambient air quality standard, and the submission, upon request, of data related to such air

quality modeling to the Administrator. 

As documented in Chapter 2 of the Final Serious Area Ozone SIP for Maricopa County,

the MAG 1993 Ozone Plan for the Maricopa County Area was submitted to EPA on

November 15, 1993, followed by an Addendum in April 1994. The 1993 Ozone Plan was

designed to meet the Moderate Area ozone requirements. The Modeling Attainment

Demonstration for the 1993 Plan was submitted in November 1994, and in April 1995, the

revisions to the Modeling Attainment Demonstration were submitted. EPA determined the

submissions to be complete on May 12, 1995.

Effective June 26, 1998, the Environmental Protection Agency then promulgated a Federal

Implementation Plan which demonstrated the 15 Percent Rate of Progress goal would be

met by April 1, 1999 (see 63 FR 28898, May 27, 1998). On July 6, 1999, EPA finalized a

rule to make minor changes to the FIP (see 64 FR 36243).

On May 30, 2001, EPA published a final determination that the Phoenix metropolitan

Serious ozone nonattainment area had attained the one-hour ozone standard by the

required Clean Air Act deadline of November 15, 1999. Based upon that determination,

EPA also determined that the Clean Air Act’s requirements for reasonable further progress

and attainment demonstrations for the one-hour standard are not applicable for so long as

the Phoenix metropolitan area continues to attain the one-hour ozone standard.

In this One-Hour Ozone Redesignation Request and Maintenance Plan, Chapter Three

describes the air quality modeling for the maintenance demonstration. The air quality

modeling is described in detail in the Technical Support Document (TSD) Ozone Modeling

in Support of the One-Hour Ozone Redesignation Request and Maintenance Plan for the

Maricopa County Nonattainment Area. Chapter VI includes several key elements of the

ozonemodeling, includingidentification of future years, committed control measures, future

year emission inventories, and maintenance demonstration. 

(9) Consultation and Participation by Local Political Subdivisions Affected by the SIP

Evidence for consultation and participation by local political subdivisions affected by the

SIP can be found in Chapter Ten, Public Participation in the Revised MAG 1999 Serious

Carbon Monoxide Plan (page 10-1). The decision-making structure of the Maricopa

Association of Governments includes twenty-five cities and towns, the Salt River PimaMaricopa and Gila River Indian Communities, Maricopa County and the Arizona

Department of Transportation. 

Appendix A, Exhibit 2 -1992 Memorandum of Agreement for Air Quality Planning from the

Revised MAG 1999 Serious Area Carbon Monoxide Plan, and Chapter One of this
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document detail the consultation and participation process for development of the local air

quality plans.

(10) Meet the Applicable Requirements of Part D

The requirement for Nonattainment Plan Provisions are established in Part D, Subpart 1,

Section 172(c), and in Subpart 2, Section 182. Section 172 lists general nonattainment

plan provisions, and Subpart 2, Section 182 lists additional provisions for ozone

nonattainment areas. In those instances where an area is subject to both the general

nonattainment provisions in subpart 1 as well as one of the pollutant-specific subparts, the

general provisions may be subsumed within, or superseded by, the more specific

requirements of Subpart 2.

Subpart 1, Section 172(c), Nonattainment Plan Provisions

1. Implement all reasonably available control measures as expeditiouslyas practicable

The fifty-five control measures in Chapter Eight of the Revised Serious Area Carbon

Monoxide Plan (page 8-5) have been implemented. Many of these measures reduce

ozone as well as carbon monoxide and go well beyond reasonably available control

measures. The effective implementation of the measures in the adopted plan was an

important element in achieving attainment before the required date of December 31, 2000

for carbon monoxide and November 15, 1999 for ozone. Effective and expeditious

implementation of the control measures resulted in meeting the standard before the

attainment date and will also assist in the continued maintenance of that standard. The

Final Serious Area Ozone SIP also contains reasonably available control technologies

which reduce volatile organic compounds (Chapter 2 on page 2-2 and Appendix A).

In addition, the Maricopa County Environmental Services Department reviews the

implementation status of the various measures contained in the air quality plans on an

annual basis. In order to accurately monitor or track plan implementation, the Maricopa

County Environmental Services Department requests that the implementing agencies and

jurisdictions complete an annual progress report form. The Environmental Services

Department reviews and summarizes this information, preparing an implementation status

report, and then presents the report to the MAG Air Quality Technical Advisory Committee.

The most recent progress report at the time of the Revised 1999 Serious Area Carbon

Monoxide Plan was the MAG Air Quality Plan 1996 Annual Progress Report (July 1998)

that was provided in Appendix B, Exhibit 2 (see also Chapter 8 Tracking Plan

Implementation, page 8-146).

2. Plans shall require reasonable further progress

In Part D of the Clean Air Act, Section 171 indicates that the term “Reasonable Further

Progress” means such “annual incremental reductions in emissions of the relevant air

pollutant as are required by this part or may reasonable be required by the Administrator
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for the purpose of ensuring attainment of the applicable national ambient air quality

standard by the applicable date.” 

On May 30, 2001, the Environmental Protection Agency published a final Determination

of Attainment of the One-Hour Ozone Standard for the Phoenix Metropolitan Area,

effective June 29, 2001. EPA indicated that because the area has monitored attainment

of the standard based on existing controls, additional measures or demonstrations to show

attainment would not be necessary. Also, EPA indicated that further emission reductions

to meet the Reasonable Further Progress/Rate of Progress provisions of sections172(c)(2)

or 182(c)(2)(B) for Serious Areas have already been fulfilled (see 66 FR 29233, May 30,

2001). In the May 10, 1995 EPA memorandum regarding “Reasonable Further Progress,

Attainment Demonstration and Relaxed Requirements for Ozone Nonattainment Areas

Meeting the Ozone National Ambient Air Quality Standards,” EPA indicates that the

requirements relating to the attainment demonstration and reasonable further progress

demonstration are not required as long as the area continues to meet the standard.

However, in order to track the progress of the maintenance plan, periodic emission

inventories will be prepared every three years in accordance with Section 182(a)(3) of the

Clean Air Act. Maricopa County will coordinate and compile the inventory with input and

assistance from the Arizona Department of Environmental Quality, Arizona Department of

Transportation, and Maricopa Association of Governments, as described in the 1992 Air

Quality Memorandum of Agreement. Changes in the inventory will be reviewed and

evaluated through the regional air quality planning process to determine if additional

measures should be considered. 

3. Plans shall include a comprehensive, accurate, current inventory of actual

emissions from all sources of the relevant pollutant or pollutants in the area and

periodic revisions

The Clean Air Act requires a comprehensive, accurate, and current inventory of actual

emissions from all sources. On April 1, 1993, the 1990 base year emission inventory for

the Maricopa County ozone nonattainment area was submitted to EPA. Full approval of

the inventory became effective on June 26, 1998 (see 63 FR 28898, May 27, 1998). The

1996 base year (July through September 1996) ozone inventory was submitted as part of

the Final Serious Area Ozone SIP, Appendix E.

The 1999 Periodic Ozone Emissions Inventory for the Maricopa County Nonattainment

Area is included in this One-Hour Ozone Redesignation Request and Maintenance Plan

in Appendix A, Exhibit 1. The document includes a complete description of the sources

and methodology used to calculate ozone emissions. The 1999 inventory was submitted

to EPA in August 2002.

The sources of emissions are grouped into five major categories: area, nonroad mobile,

onroad mobile, biogenic, and point. Collectively these five sources contributed a total of

266 metric tons of NOx

 and 307 metric tons of volatile organic compounds per day in 1999
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(see Table III-7 on page III-34 in the Technical Support Document for the One-Hour Ozone

Redesignation Request and Maintenance Plan).

In addition, the One-Hour Ozone Redesignation Request and Maintenance Plan contains

a description of the base year 1998 and 1999, the interim year 2006, and the maintenance

year 2015 ozone precursor emission inventories for use in the Urban Airshed Model

simulations (see Chapter Three of the One-Hour Ozone Maintenance Plan and Section III

of the Technical Support Document for the One-Hour Ozone Maintenance Plan).

The Maricopa County Environmental Services Department has commenced work on the

2002 periodic emissions inventory. It is anticipated that the inventory will be completed by

the second quarter of 2004.

4. The plan provisions shall identify and quantify the emissions of any pollutant

allowed from the construction and operation of major new or modified stationary

sources in the area

Chapter Three of the One-Hour Ozone Redesignation Request and Maintenance Plan

describes stationary source emissions, including major new or modified sources. Section

III in the Technical Support Document for the One-Hour Ozone Redesignation Request

and Maintenance Plan documents the impacts from major stationary sources. The 1992

Memorandum of Agreement for Air Quality Planning found in Appendix A, Exhibit 2, of the

Revised MAG 1999 Serious Area Carbon Monoxide Plan provides the distribution of

responsibilities for local air quality planning. The Maricopa County Environmental Services

Department regulates stationary sources in Maricopa County through the Maricopa County

Air Pollution Control Regulations, including Regulation II - Permit and Fees, and Rule 240 -

Permit Requirements for New Major Sources and Major Modifications to Existing Major

Sources.

Section 172(c)(4) requires an area, in developing its plan for attainment, to identify

expected emissions increases that will result from new or modified major sources in a

"zone to which economic development should be targeted" according to

Section 173(a)(1)(B). These provisions effectively allow the State to provide a "growth

allowance" for sources in such an area in lieu of the offset requirements under

Section 173(a)(1)(A). Since this is an optional alternative to requiring the acquisition of

offsets under Section 173(a)(1)(A), it is not a prerequisite to redesignation. Moreover, once

the area is redesignated attainment, these provisions will not apply since the Prevention

of Significant Deterioration (PSD) requirements of Part C will become effective.

5. The plan provisions shall require permits for the construction and operation of new

or modified major stationary sources anywhere in the nonattainment area

Generally, the requirements of the Part D New Source Review (NSR) permitting

nonattainment program will be replaced by the Prevention of Significant Deterioration

(PSD) program once an area is redesignated to attainment. However, to ensure that the

PSD program can become fully effective immediately upon redesignation, EPA will require
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an area to make any needed NSR corrections to their Part C NSR programs prior to

redesignation. 

Maricopa County received SIP approval of its major and minor source NSR program in

1988 (see 53 FR 30220, 53 FR30224, and 53 FR 30238, August 10, 1988). Effective

November 22, 1993,EPAdelegated Prevention of Significant Deterioration (PSD) authority

to Maricopa County via a PSD Delegation Agreement. On August 15, 1994, ADEQ

submitted a SIP revision containing portions of the State permitting program that are

applicable to major sources, major source modifications, and minor sources. Part of the

SIP revision, under a separate cover, included applicable Maricopa County rules, pertinent

to the NSR/PSD program. The amendments to Maricopa County Rules 100, 200, 210,

220, 240, and Appendix B were submitted as a revision to the NSR/PSD program. The

submittal also requested approval of synthetic minor provisions under Section 112 (l) of the

CAA. On September 1, 1994, EPA deemed both the ADEQ and Maricopa County SIP

revision complete and each is currently awaiting full approval. To assure adequate SIP

revisions required by Section 110(a)(2)(E) of the CAA, the Director of ADEQ is authorized

under ARS §§ 49-402B to assert jurisdiction over major NSR/PSD and minor NSR sources,

excluding those located on Indian Reservations. ADEQ received SIP approval of its

NSR/PSD program effective May 3, 1983 and delegation of PSD authority for PM-10

effective March 12, 1999.

The EPA guidance memorandum, Part D New Source Review (Part D NSR) Requirements

for Areas Requesting Redesignation to Attainment, October 14, 1994, states that

“nonattainment areas may be redesignated to attainment notwithstanding the lack of a

fully-approved Part D NSR program, provided the program is not relied upon for

maintenance.” In addition, the EPA guidance indicates that Part D NSR rules do not need

to be placed in the contingency portion of the maintenance plan. It is important to note that

the One-Hour Ozone Maintenance Plan for the Maricopa County nonattainment area does

not rely on credit for the NSR program to demonstrate maintenance. 

6. Include enforceable emission limitations and other control measures, means, or

techniques, as well as schedules and timetable for compliance to provide for

attainment of such standard

Since attainment has been achieved, no additional measures are needed to provide for

attainment. The need for additional measures to ensure that maintenance continues is

addressed under the requirements for maintenance plans. Areas should consider the need

for offsets under the Part C program to ensure that new sources do not "cause or

contribute" to an increase in pollutant levels that would take the area out of compliance.

7. Plans shall meet the applicable requirements of Section 110(a)(2)

In the requests for SIP redesignation, States must show that their plans satisfy the

requirements under Section 110. These requirements specify that the plans must contain

enforceable emission limits, monitoring requirements, procedures to prevent interstate

pollution problems, adequate resources to carry out the control programs, and other
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provisions related to the development and administration of effective air pollution control

programs.

The Arizona Revised Statutes Title 49-401 through 470 contain the requirements for the

State Air Pollution Control Program administered by the Arizona Department of

Environmental Quality. Also, the Arizona Revised Statutes Title 49-471 through 516

contain the requirements for the County Air Pollution Control Program. The Maricopa

County Environmental Services Department is the local air pollution control department for

Maricopa County. In addition, the State and local government commitments to implement

specific air quality measures address the actual implementation and resources necessary

for a wide variety of measures. The Commitments documents which accompany the

Revised MAG 1999 Serious Area Carbon Monoxide Plan include the State legislation and

local government commitments for measure implementation.

The Final Serious Area Ozone SIP for Maricopa County also includes the Reasonably

Available Control Technology Rules designed to control VOC emissions. A list of Maricopa

County Ozone Nonattainment Area Control Measures is provided in Appendix A of the

document.

The Arizona SIP already includes the provisions required by Section 110(a)(2) and Part D

of the Clean Air Act. In approving the Revised MAG 1999 Serious Area Carbon Monoxide

Plan, Carbon Monoxide Redesignation Request and Maintenance Plan, and Final Serious

Area Ozone SIP EPA will be determining that the State has met the requirements of

Section 110(a)(2) and Part D of the Clean Air Act.

8. States may use equivalent techniques for modeling, emission inventories, planning

procedures unless they are less effective than the methods specified by the

Administrator

The provisions of Section 172(c)(8) allow the State to use equivalent techniques for

modeling, inventorying, or other planning activities unless EPA determines that the

techniques are less effective. This allowance will continue to apply with respect to the

requirements of the maintenance plan.

9. Provide for specific contingency measures to be undertaken if the area fails to make

reasonable further progress, or to attain the NAAQS by the applicable attainment

date

The Section 172(c)(9) requirements for contingency measures are directed at ensuring

reasonable further progress and attainment by the applicable date. These requirements

no longer apply when an area has attained the standard and is eligible for redesignation.

In the Determination of Attainment of the One-Hour Ozone Standard for the Phoenix

Metropolitan Area, effective June 29, 2001, EPA also determined that the Clean Air Act

requirements for contingency measures are not applicable to the area for so long as the

Phoenix metropolitan area continues to attain the one-hour ozone standard (see 66 FR

29230, May 30, 2001).
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Section 175 (A) for maintenance plans provides specific requirements for contingency

measures that effectively supersede the requirements of Section 172(c)(a) for these areas.

The One-Hour Ozone Redesignation Request and Maintenance Plan includes contingency

provisions and measures. The three contingency measures are: Area A Expansion, Gross

Polluter Option for I/M Program Waivers, and Increased Waiver Repair Limit Options.

Emissions reduction credit for these contingency measures was not taken in the

maintenance demonstration. These contingency measures and other contingency

provisions are described in Chapter Three of the One-Hour Ozone Redesignation Request

and Maintenance Plan and Section VI of the Technical Support Document for the OneHour Ozone Maintenance Plan.

Subpart 2, Section 182(b), Plan Submissions and Requirements, Serious Area

Requirements

1. Meet requirements for Moderate nonattainment areas

1. Emissions Inventory

The State is required to submit a comprehensive, accurate, and current emission inventory

of all sources as described in Section 182(a)(1). This requirement was also addressed

earlier in paragraph 3 of the requirements for Subpart 1, Section 172(c)(3), Nonattainment

Plan Provisions. On May 27, 1998, the EPA approved the 1990 base year emission

inventory submitted in the MAG 1993 Ozone Plan for the Maricopa County Area.

b. Periodic Emissions Inventory, no later than every three years until attainment

of the standard

This requirement was addressed earlier in this section under requirements for Section 172,

Nonattainment Plan Provisions. Appendix E of the Final Serious Area Ozone State

Implementation Plan for Maricopa County contains the 1996 periodic emission inventory

completed by the Maricopa County Environmental Services Department for three ozone

precursors: volatile organic compounds, carbon monoxide, and nitrogen oxides. In

addition, the Maricopa County Environmental Services Department has completed a

periodic emissions inventory for 1999, the latest version of which was submitted to EPA

in August, 2002. The 1999 Periodic Ozone Emissions Inventory is included in Appendix

A, Exhibit 1 of the One-Hour Ozone Redesignation Request and Maintenance Plan.

c. Submission of the 15 Percent Rate of Progress Plan for volatile organic

compounds

The State is required to submit a revision to the applicable implementation plan to provide

for volatile organic compound emission reductions of 15 percent from baseline emissions

and shall provide for such specific annual reductions in emissions of VOCs and NOx as

necessary to attain the standard. In order to meet the Moderate area requirements, the

MAG 1993 Ozone Plan for the Maricopa County Area was submitted to EPA by November

15, 1993. An Addendum to this Plan which contained additional control measures was
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submitted to EPA in March 1994. In accordance with Section 182(f), a NOx exemption

petition was approved by EPA for the Maricopa County Nonattainment Area on April 19,

1995. The MAG 1993 Ozone Plan and Addendum, as well as an attainment demonstration

was found complete by EPA on May 12, 1995.

Effective June 26, 1998, the Environmental Protection Agency promulgated a Federal

Implementation Plan which demonstrated that the 15 Percent Rate of Progress (ROP) goal

would be met by April 1, 1999 (see 63 FR 28898, May 27, 1998). On July 6, 1999, EPA

finalized a rule to make minor changes to the FIP which did not alter the conclusion that

the 15 Percent ROP requirement had been met (see 64 FR 36243).

d. Reasonably Available Control Technology

In accordance with Section 182(a)(2)(A), the state is required to submit a revision that

includes provisions to correct requirements in (or add requirements to) the plan concerning

reasonably available control technology as required under Section 172(b) in effect before

the 1990 amendments to the Clean Air Act. The source categories subject to the

Reasonably Available Control Technology corrections may be found in Chapter 2 of the

Final Serious Area Ozone State Implementation Plan for Maricopa County. The source

categories are summarized below.

• Architectural Coatings. EPA approved Maricopa County Rule 335 as a SIP revision

effective on March 6, 1992.

• Surface Coating Operations. EPA approved Maricopa County Rule 336 as a SIP

revision effective on November 19, 1999.

• Solvent Cleaning. EPA finalized a limited approval and limited disapproval of revisions

to Maricopa County Rule 331 as a SIP revision effective on May 16, 2003.

• Petroleum Solvent Dry Cleaning. EPA approved revisions to Maricopa County Rule

333 as a SIP revision effective on March 11, 1998.

• Cutback and Emulsified Asphalt. EPA approved Maricopa County Rule 340 as a SIP

revision effective on March 4, 1996.

• Storage of Organic Liquids at Bulk Plants. EPA approved Maricopa County Rule 350

as a SIP revision effective on October 5, 1995.

• Loading Organic Liquids. EPA approved Maricopa County Rule 351 as a SIP revision

effective October 5, 1995.

• Transfer of Gasoline into Stationary Dispensing Tanks. EPA approved Maricopa

County Rule 353 as a SIP revision effective March 4, 1996.

• Gasoline Delivery Vessel Testing and Use. EPA approved Maricopa County Rule 352

as a SIP revision effective October 5, 1995.

• Graphic Arts. EPA approved revisions to Maricopa County Rule 337 as a SIP revision

effective March 11, 1998.

Under Section 182(b)(2)(A), the state is to implement reasonably available control

technology for VOC sources in the area covered by a control techniques guideline

document issued by EPA between the Clean Air Act Amendment enactment date and the

date of attainment. The source categories subject to this requirement may be found in
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Chapter 2 of the Final Serious Area Ozone State Implementation Plan for Maricopa

County. A negative declaration was submitted in March 2000 for two source categories

which are not present in the Maricopa County nonattainment area, Ship Building and

Repair and Distillation Operations Process. A copy of this declaration may be found in

Appendix B of the Serious Area Ozone Plan. The source categories meeting this

requirement are summarized below.

• Coating Wood Furniture and Fixtures. EPA approved Maricopa County Rule 342 as

a SIP revision effective March 11, 1998.

• Aerospace Manufacturing and Rework Operations. EPA approved Maricopa County

Rule 348 as a SIP revision effective November 19, 1999.

Under Section 182(b)(2)(B), the state is to implement reasonably available control

technology for VOC sources covered by any control techniques guideline before the Clean

Air Act Amendment enactment date. There are no other source categories subject to this

provision, other than the source categories subject to the correction requirements in

Section 182(A) of the Clean Air Act. A negative declaration was submitted by the state in

April 1993 for these source categories.

In addition, Section 182(b)(2)(C) requires the state to implement reasonably available

control technology for all other major stationary sources of VOCs that are located in the

area. Any stationary source or group of sources that emits or has the potential to emit at

least 50 tons of volatile organic compounds meets the Clean Air Act definition of a “major

source” and “major stationary source”. The source categories meeting this requirement

are summarized below.

• Rubber Sports Ball Manufacturing. EPA approved revisions to Maricopa County Rule

334 as a SIP revision effective on March 11, 1998.

• Metal Casting. EPA approved Maricopa County Rule 341 as a SIP revision effective

March 13, 1996.

• Commercial Bread Bakeries. EPA approved Maricopa County Rule 343 effective

May 16, 1997.

• Semiconductor Manufacturing. EPA approved Maricopa County Rule 338 effective

March 11, 1998.

• Vegetable Oil Extraction Processes. EPA approved Maricopa County Rule 339

effective March 11, 1998.

• Coating Wood Millwork. EPA approved Maricopa County Rule 346 effective

March 11, 1998.

• Ferrous Sand Casting. EPA approved Maricopa County Rule 347 effective August 11,

2000.

• Vitamin Manufacturing. EPA approved Maricopa County Rule 349 effective August 7,

2001.

To fulfill the CAA sections § 182(a)(2)(A) and (b)(2), Maricopa County proposes to

complete three outstanding processes to implement RACT. The processes include

completing rule revisions to Rule 331 to address the May 16, 2003 limited approval and

limited disapproval, development of new Rule 358, and issuance of a Title V permit to
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impose source-specific RACT for another major source. Maricopa County's proposed

commitment to complete these actions as expeditiously as practicable is in Appendix B,

Exhibit 1 of this One-Hour Ozone Redesignation Request and Maintenance Plan. The

proposed implementation schedule from that commitment follows:

Implementation Schedule:

Revise Rule 331 Solvent Cleaning: 

November-December 2003 Conduct workshops and stakeholder meetings.

February-March 2004 Publish Notice of Proposed Rulemaking and conduct

Oral Proceeding.

April-May 2004 Board consideration and action on Draft Notice of Final

Rulemaking.

May-June 2004 Rule becomes effective 30 days after Board action as

the revisions are administrative. 

July 2004 Submit rule to EPA.

New Rule 358 Polystyrene Foam Operations

November-December 2003 Publish Notice of Proposed Rulemaking and conduct

Oral Proceeding.

February-March 2004* Board consideration and action on Draft Notice of Final

Rulemaking.

March-April 2004 Rule becomes effective 30 days after Board action as

the revisions are administrative. Proposed

implementation schedule requires installation of

controls within 18 months of rule adoption.

April-June 2004 Submit rule to EPA.

*Add two—three additional months if public comments require a substantive revision to the

proposed rule

Source Specific RACT by Permit

October-December 2003 Notification of availability of draft Title V permit

published. Comment period closes December 5, 2003.

1. No public comment or extension request:
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December 2003 Submit to EPA for 45-day review and comment.

February 2003 Address comments and finalize permit.

February-March 2004 Publish notice of SIP revision and hold public hearing.

April 2004 Submit source-specific RACT provisions from permit to

EPA.

February-May 2004 Complete design and award contracts for emission

control system (ECS)

January 2005 Complete installation of ECS

March 2005 Complete performance testing on new ECS

2. Extension request without public comment adds 30 days to schedule in 1.

3. Public comment without a request for public hearing adds 15 additional days to

1 and 2.

4. Public Hearing request will add 90 additional days to schedule for 1 and 2. EPA

may also find it necessary to request an extension of their comment period.

5. EPA objections will add another 90 days for Department response plus another

45 day EPA review period to schedule in 1. 

In the Final Serious Area Ozone Plan another major source, a fiberglass boat

manufacturer, was included in the County's commitment to impose source-specific RACT

standards in a Title V permit. Sea Ray Boats, Inc. closed in December 2001 prior to

issuance of its Title V permit. There are no other major sources in this category present

in Maricopa County that would trigger the requirement to impose RACT. As required by

the General Preamble, a negative declaration for this source category will be submitted to

EPA with this plan (see Appendix B, Exhibit 2 of this One-Hour Ozone Redesignation

Request and Maintenance Plan).

e. Gasoline Vapor Recovery

Under Section 182(b)(3), the State was required to submit a SIP revision to require all

owners or operators of gasoline dispensing systems to install and operate a system for

gasoline vapor recovery of emissions from the fueling of motor vehicles applying to

facilities which sell more than 10,000 gallons of gasoline per month (50,000 gallons per

month in the case of an independent small business marketer of gasoline as defined in

Section 324). On May 27, 1994, ADEQ submitted to EPA Stage II vapor recovery rules

that were adopted by the Arizona Department of Weights and Measures on August 27,

1993. Full approval for the program was granted by EPA effective January 3, 1995 (see
2-30

59 FR 54521, November 1, 1994). Subsequent legislative action (HB 2001, 1997) required

the Arizona Department of Weights and Measures to adopt rules to enhance the program.

Since then, a quality assurance and quality control program has been implemented by the

Department.

f. Motor Vehicle Emission Control Inspection and Maintenance Program

The State Vehicle Inspection Maintenance Program established in 1976 is designed to

promote the clean operation of motor vehicles by controlling vehicle exhaust emissions.

The program is operated by the Arizona Department of Environmental Quality and contains

the provisions listed in Section 182(a)(2)(B) of the Clean Air Act for a Vehicle Inspection

and Maintenance (I/M) Program.

The Vehicle Emissions Inspection Maintenance Program was significantly enhanced and

strengthened by the Arizona Legislature in 1993 (H.B. 2001). The Legislature established

a biennial, transient loaded (I/M 240) emissions test for gasoline powered vehicles model

year 1981 or newer with a gross vehicle weight of up to 8,500 pounds, beginning

January 1, 1995.

H.B. 2001 also increased the repair threshold limits for gasoline powered vehicles in order

to be eligible for a waiver through the Vehicle Emissions Inspection Maintenance Program.

The repair limits were increased in the following manner: 1967-1974 from $50 to $100;

1975-1980 from $200 to $300; and 1981 and newer from $300 to $450. The bill also

increased the repair threshold limits from $300 to $500 for diesel powered vehicles with

tandem axles or a gross vehicle weight in excess of 26,000 pounds.

The Arizona Legislature passed S.B. 1002 in 1996 which limits the issuance of a waiver

for failure to comply with the emission testing requirements to one-time only beginning

January 1, 1997 (A.R.S. 49-542 D.). This measure is documented in the Revised 1999

MAG Serious Area Carbon Monoxide Plan for the Maricopa County Nonattainment Area

as “One-Time Waiver from Vehicle Emissions Test,” on page 8-10; and in the Technical

Support Document, beginning on page V-14.

The Arizona Legislature passed H.B. 2237 in 1997 which contains an appropriation of

$120,000 from the State General Fund to the Arizona Department of Environmental Quality

to develop and implement an alternative test protocol to reduce the false failure rates

associated with the more stringent pass-fail standards for the Vehicle Emissions Testing

Program (Section 19 of H.B. 2237). This measure is documented in the Revised Serious

Area Carbon Monoxide Plan as “Phased-In Emission Test Cutpoints,” beginning on page

8-5; and in the Technical Support Document, beginning on page V-8.

2. Meet requirements for Serious nonattainment areas

g. Enhanced Monitoring

Following the promulgation of EPA rules relating to enhanced monitoring for ozone, oxides

of nitrogen, and volatile organic compounds, Section 182(c)(1) requires the State to
2-31

improve monitoring for ambient concentrations of ozone, oxides of nitrogen, and volatile

organic compounds and to improve monitoring of emissions of oxides of nitrogen and

volatile organic compounds. To meet the requirements in Section 182, EPA revised 40

CFR Part 58 which calls for the establishment of a Photochemical Assessment Monitoring

Stations (PAMS) network. The Final Serious Area Ozone State Implementation Plan for

Maricopa County indicates that the ADEQ is phasing in the PAMS network consistent with

40 CFR Part 58 requirements and other relevant EPA guidance. The PAMS network

measures ozone, NOx, and various VOCs, and surface and upper air meteorology.

h. Attainment Demonstration and Reasonable Further Progress Demonstration

Under Section 182(c)(2), the State is to submit a SIP revision demonstrating that the Plan

will provide for attainment of the one-hour ozone NAAQS by the applicable attainment

date. The attainment demonstration must be based on photochemical grid modeling or

any other analytical method as determined by EPA. The serious area attainment date for

the Maricopa County area was November 15, 1999. In addition, a SIP revision is required

from the State demonstrating reasonable further progress that would result in emission

reductions of ozone precursors of at least three percent of baseline emissions between

1996 and 1999 (9 Percent Rate of Progress Plan). 

In the Determination of Attainment of the 1-Hour Ozone Standard for the Phoenix

Metropolitan Area, effective June 29, 2001, EPA indicated that because the area has

monitored attainment of the standard based on existing controls, contingency measures

and demonstrations to show attainment would not be necessary (see 66 FR 29230 May

30, 2001). EPA also indicated that further emission reductions to meet the RFP/ROP

provisions of sections 172(c)(2) or 182(c)(2)(B) for serious areas have already been

fulfilled. In the May 10, 1995 EPA memorandum regarding “Reasonable Further Progress,

Attainment Demonstration, and Related Requirements for Ozone Nonattainment Areas

Meeting the Ozone National Ambient Air Quality Standards”, EPA believes that the

requirements relating to the attainment demonstration and reasonable further progress

demonstration are not required as long as the area continues to meet the standard.

i. Enhanced Vehicle Inspection and Maintenance Program

An enhanced vehicle emissions inspection and maintenance program is operated in Area

A of Maricopa and Pinal Counties by the Arizona Department of Environmental Quality.

The program contains the provisions in Section 182(c)(3) of the Clean Air Act for an

Enhanced Vehicle Inspection and Maintenance Program. The State’s complete inspection

and maintenance program is documented in the Final Arizona State Implementation Plan

Revision, Basic and Enhanced Vehicle Emissions Inspection/Maintenance Programs,

Volumes 1 and 2, Air Quality Division, Arizona Department of Environmental Quality,

June 2001. EPA proposed approval of the Arizona I/M program in August 2002 and signed

the final approval notice on October 31, 2002. The final approval notice was published in

the Federal Register on January 22, 2003.
2-32

j. Clean-Fuel Vehicle Programs

Under Section 182(c)(4), the state, except to the extent that substitute provisions have

been approved by EPA, will submit a SIP revision for each area described under part C of

Title II to include such measures necessary to ensure the effectiveness of the applicable

provisions of the clean-fuel vehicle program, including all measures necessary to make the

use of clean alternative fuels in clean fuel vehicles (as defined in part C of Title II)

economic from the standpoint of vehicle owners. ADEQ submitted a SIP revision to EPA

on December 7, 1998 requesting that a portion of the emissions reductions attributable to

the Cleaner Burning Gasoline program be approved as a substitute provision for the CleanFuel Vehicle Program requirements. The SIP revision is awaiting approval from EPA.

j. Transportation Control

Section 182(c)(5) requires the state to submit a demonstration as to whether current

aggregate vehicle mileage, aggregate vehicle emissions, congestion levels, and other

relevant parameters are consistent with those used for the area’s attainment

demonstration. Where such parameters exceed the levels projected in the attainment

demonstration, the state will submit a SIP revision to include transportation control

measures from Section 108(f) to reduce emissions levels consistent with the attainment

demonstration. EPA believes that the requirements relating to the attainment

demonstration and reasonable further progress demonstration, including, transportation

control requirements, are not required as long as the area continues to meet the standard.

This EPA policy is provided for in the May 10, 1995 EPA memorandum regarding

“Reasonable Further Progress, Attainment Demonstration, and Related Requirements for

Ozone Nonattainment Areas Meeting the Ozone National Ambient Air Quality Standards”.

l. New Source Review Provisions

The new source review (NSR) provisions required under the Clean Air Act Section

182(c)(6), (7), and (8) may be found in Chapter 2 of the Final Serious Area Ozone State

Implementation Plan for Maricopa County. These provisions describe the applicability of

permit requirements under the Clean Air Act for increased emissions of volatile organic

compounds resulting from any physical change in, or change in the method of operation

of a stationary source. Arizona Revised Statutes Section 49-402(A) and (B) describes the

provisions for new source review and prevention of significant deterioration (PSD) required

under the Clean Air Act for the state. A state implementation plan revision for portions of

the major source permitting and modifications, and minor sources was submitted to EPA

on August 15, 1994. Maricopa County also submitted Rules 100, 200, 210, 220, 240, and

Appendix B as a revision to the NSR/PSD program. These revisions were found to be

complete by EPA on September 1, 1994. EPA approval may be forthcoming.

Conformity Requirements

In addition to the above requirements, the State Implementation Plan must demonstrate

that its provisions are consistent with Section 176(c)(4) conformity requirements. These

provisions ensure that federally funded or approved projects and actions and other

regionally significant projects conform to the State Implementation Plan prior to the projects

or actions being implemented.
2-33

State rules for transportation conformity were adopted on April 12, 1995, by the Arizona

Department of Environmental Quality, in response to requirements in Section 176(c)(4)(C)

of the Clean Air Act as amended in 1990. These rules became effective upon their

certification by the Arizona Attorney General on June 15, 1995 and, as required by the

federal conformity rule, were submitted to EPA as a revision to the State transportation

conformity SIP.

To date, a State transportation conformity SIP has not received approval by EPA. Section

51.390(b) of the federal conformity rule states: “Following EPA approval of the State

conformity provisions (or a portion thereof) in a revision to the applicable implementation

plan, conformity determinations would be governed by the approved (or approved portion

of the) State criteria and procedures.” The federal transportation conformity rule therefore

still governs, as a transportation conformity SIP has not yet been approved for this area.

The State rule specifies that Metropolitan Planning Organizations (i.e., MAG, for this

region) must develop specific conformity guidance and consultation procedures and

processes. MAG has developed and adopted two conformity guidance documents to meet

State requirements. MAG developed the “Transportation Conformity Guidance and

Procedures” document, which was adopted initially on September 27, 1995 by the MAG

Regional Council. The document was revised by the MAG Regional Council on

March 27, 1996. This guidance document addresses both the determination of “regional

significance” status for individual transportation projects, and the process by which

regionally significant projects may be approved.

MAG also developed the “Conformity Consultation Processes” document, which was

adopted on February 28, 1996 by the MAG Regional Council. This guidance document

details the public and interagency consultation processes to be used in the development

of regional transportation plans, programs, and projects within the Maricopa County

nonattainment area. Adherence to the above rules, guidance, procedures, and processes

ensure that the SIP provisions are consistent with conformity requirements.
3-1

CHAPTER THREE

MAINTENANCE PLAN

Section 107(d)(3)(E) of the Clean Air Act stipulates that for a nonattainment area to be

redesignated to attainment, Environmental Protection Agency (EPA) must fully approve a

maintenance plan which meets the requirements of the Clean Air Act Section 175A. The

maintenance plan is a State Implementation Plan (SIP) revision and must provide for

maintenance of the relevant National Ambient Air Quality Standards (NAAQS) in the area

for at least ten years after redesignation by EPA. 

In determining the amount of lead time to allow, EPA indicated that 18 months, as granted

in section 107(d)(3)(D) of the Clean Air Act, should be assumed for EPA to approve a

redesignation request. Due to uncertainties regarding the time that the area will be

redesignated to attainment, the year 2015 was modeled to assure that the one-hour ozone

NAAQS is maintained at least ten years past an official notice of redesignation to

attainment by EPA.

The EPA has established the core elements listed below as necessary for approval of

maintenance plans.

1. Description of the control measures for the maintenance period

2. Emission inventories for base and future years

3. Maintenance demonstration

4. Mobile source emissions budget

5. Approved monitoring network

6. Verification of continued attainment

7. Contingency plan

8. Subsequent maintenance plan revisions

MAINTENANCE PLAN CONTROL MEASURES

Generally, the overall approach taken in preparing the One-Hour Ozone Maintenance Plan

is to demonstrate maintenance of the one-hour ozone standard in 2015 with the committed

measures in the Revised MAG 1999 Serious Area Carbon Monoxide Plan and Carbon

Monoxide Redesignation Request and Maintenance Plan, since most of those measures

also reduce ozone. Therefore, the Ozone Maintenance Plan relies heavily upon the

Revised MAG Serious Area Carbon Monoxide Plan and its supporting documents,

including the commitments to implement control measures. The Ozone Maintenance Plan

also relies upon the Final Serious Area Ozone State Implementation Plan for Maricopa

County and the modified Arizona Cleaner Burning Gasoline Program. 

Descriptions of the committed control measures in the maintenance plan are organized in

three groups below. The first group of measures includes those for which numeric credit

is assumed in the maintenance demonstration. The combined emission reduction impact
3-2

of this class of measures, described as maintenance measures, is reflected in the 2015

modeling inventory described in Section VI-3 of the Technical Support Document (TSD).

The control measures that are included in this analysis as maintenance measures include

Summer Fuel Reformulation: California Phase 2 and Federal Phase II Reformulated

Gasoline with 7 psi from May 1 through September 30, Phased-In Emission Test Cutpoints,

One-time Waiver from Vehicle Emissions Test,CoordinateTraffic SignalSystems, Develop

Intelligent Transportation Systems, Tougher Enforcement of Vehicle Registration and

Emission Test Compliance, and Maricopa County Rule 348: Aerospace Manufacturing and

Rework Operations. The maintenance measures are listed in Table 3-1. 

The second group of measures includes the committed measures that are part of the

contingency plan described in Section VI-5 of TSD. For these measures, no credit was

taken in the maintenance demonstration. The impact of these measures is not reflected

in the 2015 modeling inventory in Section VI-3 of TSD. The control measures that are

included in this analysis as contingency measures include Expansion of Area A

Boundaries, Gross Polluter Option for I/M Program Waivers, and Increased Waiver Repair

Limit Options. Descriptions of the contingency measures are summarized in Section VI of

TSD, with more detailed descriptions provided in Appendix VI of TSD. 

The third group of measures includes additional measures for which commitments were

received, but numeric emission reduction credit was not taken. The impacts of these

measures are not readily quantifiable. However, these measures represent additional

legally-enforceable commitments to reduce emissions and improve air quality in the region.

A summary of the committed maintenance and contingency measures is provided in

Table 3-1. The general approaches used to model the emission reductions from the

individual measures are similar to those used in the Carbon Monoxide Maintenance Plan,

although exceptions are necessary due to seasonal differences. Figures 3-1 and 3-2

illustrates the emission reduction impact of the individual maintenance measures in 2015

for NOx and VOC, respectively. Table 3-2 quantifies the emission reductions from the

committed maintenance measures in metric tons per day. The base total emissions in

Table 3-2 were estimated by assuming that none of the maintenance measures, including

the Federal Offroad Vehicle and Engine Standards, are implemented in 2015. The

comparison of the base emissions with the maintenance measure package in 2015 is

exhibited in Table IV-3 of the Technical Support Document.

Measures Used for Numeric Credit

The seven maintenance measures assumed in modeling maintenance of the one-hour

ozone standard through 2015 are described in Chapter Two. Figures 3-1 and 3-2 identifies

the emission reduction credit for each of the individual maintenance measures. These

measures are described in detail in Section VI-2-1 of the Technical Support Document.
3-3

TABLE 3-1

COMMITTED MAINTENANCE AND CONTINGENCY MEASURES

IN THE ONE-HOUR OZONE MAINTENANCE PLAN

Maintenance Measures Used for Numeric

Credit Contingency Measures

1. Summer Fuel Reformulation: California

Phase 2 and Federal Phase II Reformulated

Gasoline with 7 psi from May 1 through

September 30

1. Expansion of Area A Boundaries

2. Phased-In Emission Test Cutpoints 2. Gross Emitter Waiver Provision

3. One-time Waiver from Vehicle Emissions

Test

3. Increased Waiver Repair Limit

4. Coordinate Traffic Signal Systems

5. Develop Intelligent Transportation Systems

6. Tougher Enforcement of Vehicle

Registration and emission Test Compliance

7. Maricopa County Rule 348: Aerospace

Manufacturing and Rework Operations
3-4
3-5
3-6

TABLE 3-2

SUMMARY OF 2015 EMISSION REDUCTIONS IN NONATTAINMENT AREA FROM

COMMITTED MAINTENANCE MEASURES USED FOR NUMERIC CREDITa

NOx VOC

Base Total Emissions (metric

tons/day) 232.7 b 413.9 b

Maintenance Measure

Emission

Reductions

(metric

tons/day)

Percent

Reduction in

Emissions

Emission

Reductions

(metric

tons/day)

Percent

Reduction in

Emissions

Summer Fuel Reformulation:

California Phase 2 and Federal Phase

II Reformulated Gasoline with 7 psi

from May 1 through September 30

4.1 1.8% 1.9 0.6%

Phased-In Emission Test Cutpoints < 0.1

(increase)

< 0.1%

(increase)

0.1 <0.1%

One-time Waiver from Vehicle

Emissions Test

0.1 <0.1% 0.1 <0.1%

Coordinate Traffic Signal Systems 0.1 <0.1% 0.3 0.1%

Develop Intelligent Transportation

Systems

< 0.1

(increase)

< 0.1

(increase)

0.1 <0.1%

Tougher Enforcement of Vehicle

Registration and Emission Test

Compliance

0.2 0.1% 0.2 0.1%

Maricopa County Rule 348: Aerospace

Manufacturing and Rework Operations

N/A N/A 0.01 <0.1%

a

-Individual impact of measures is not additive.

b

-The total anthropogenic NOx and VOC emissions are 226.5and 328.1 metric tons/day, respectively.
3-7

Measures Included in the Contingency Plan

Expansion of Area A Boundaries, Gross Polluter Option for I/M Program Waivers, and

Increased Waiver Repair Limit Options are contingency measures in both the Revised

Serious Area Carbon Monoxide Plan and the Carbon Monoxide Maintenance Plan. These

measures are described in Chapter VI of the Ozone Maintenance Plan TSD. 

These three contingency measures have already been implemented in the nonattainment

area. Early implementation of contingency measures is allowed by EPA and helps to

ensure that the standard will be maintained through 2015. The Contingency Provisions

later in this Chapter identify procedures that will be followed to consider and implement

additional contingency measures, as needed. 

The contingency measures are described in Section VI-2-2 of the Technical Support

Document. 

Measures Which Improve Air Quality, But Were Not Used for Numeric Credit

The third group represents measures that were not quantified for emission reduction credit,

but are committed measures in both the attainment and maintenance plans. These nonquantified measures are described in detail in Section VI-2-3 of the Technical Support

Document.

EMISSION INVENTORIES

This section summarizes the base year 1998 and 1999, the interim year 2006, and the

maintenance year 2015 ozone emission inventories for use in the Urban Airshed Model

(UAM) simulations. The emissions inventories include onroad mobile, nonroad mobile,

point, area, and biogenic sources.

The 1998 inventory was developed for July 16-17 and the 1999 inventory was developed

for August 23-24. Both base year inventories reflected control measures in place at that

time. The future year emission inventories include projected emission reductions resulting

from committed control measures that were implemented after 1998 and 1999. Sections

III-1 and VI-3 of the Technical Support Document describe the technical details of the

emission inventories for 1998, 1999, 2006 and 2015.

Demographic and Transportation Data

Emissions for source types other than onroad mobile and biogenics were developed for

a base year and then projected to 2006 and 2015 through the application of appropriate

growth factors. The growth factors were based on the 2015 population projections

approved by the MAG Regional Council in June 1997 and developed from the 1995
3-8

Special Census. The 2015 employment factors by SIC were extrapolated from projections

prepared by the Arizona Department of Economic Security (DES) in August 1997.

On road mobile source emissions were increased by eight and twelve percent for 2006 and

2015, respectively. These increases were applied regardless of hour of the day or location

in the modeling domain, because of an expected increase in population and employment

projections for the County. The DES is in the process of developing new population

projections for the State and counties based on the 2000 Census. These projections were

not available from DES when this plan was completed. However, preliminary data indicate

that the new vehicle travel estimates will be about eight and twelve percent higher,

respectively, than previous 2006 and 2015 projections for the ozone nonattainment area.

Summary of the Emission Inventories

The 1998 and 1999 base cases, 2006 interim year, and 2015 maintenance year emission

inventories for NOx and VOC are summarized in Tables 3-3 through 3-6. 

In the 1998 and 1999 base cases, the onroad mobile emissions contribute 28 to 30 percent

of VOC emissions and 51 to 52 percent of NOx emissions and represent the largest

emissions source among all categories for both NOx and VOC species. With the

implementation of the committed maintenance measures and stricter Federal controls on

vehicles and fuels, onroad mobile NOx emissions decrease by 19.3 percent between 1999

and 2006, and 58.7 percent between 1999 and 2015. Onroad mobile VOC emissions

decrease by 32.7 percent between 1999 and 2006, and 54.4 percent between 1999 and

2015. 

Due to anticipated growth in regional population, area sources become the largest source

category for NOx and VOC emissions in 2015. Area source NOx emissions increase by

25.8 percent between 1999 and 2006, and 56.7 percent between 1999 and 2015. Area

source VOC emissions increase by 22.8 percent between 1999 and 2006, and 49.5

percent between 1999 and 2015.

As a result of expected increases in power plant emissions, point source NOx emissions

increase significantly from the base years to 2006 and 2015. Point source NOx emission

increase by 48.5 percent between 1999 and 2006, and 59.4 percent between 1999 and

2015. 

Point source VOC emissions increase by 13.7 percent between 1999 and 2006, and 32.0

percent between 1999 and 2015. With the implementation of the Federal Off-Road Vehicle

and Engine Standards, nonroad mobile NOx emissions decrease by about 14 percent

between 1999 and 2006, and about four percent between 1999 and 2015. Nonroad mobile

VOC emissions decrease by about 23 percent between 1999 and 2006, and about 63

percent between 1999 and 2015.
3-9

TABLE 3-3

SUMMARY OF NOX EMISSIONS FOR JULY EPISODE IN 1998 BASE CASE AND

2015 WITH COMMITTED MAINTENANCE MEASURES

Friday, July 17, 1998 Friday, July 2015 2015-1998 Difference

Source Category Metric Tons 

per Day

Metric Tons 

per Day

Percent

Point 18.5 23.6 27.6

Area 33.2 53.6 61.4

Nonroad Mobile 57.4 55.8 -2.8

Onroad Mobile 126.2 51.6 -59.1

Biogenics 7.9 6.7 -15.2

Total 243.2 191.3 -21.3
3-10

TABLE 3-4

SUMMARY OF VOC EMISSIONS FOR JULY EPISODE IN 1998 BASE CASE AND

2015 WITH COMMITTED MAINTENANCE MEASURES

Friday, July 17, 1998 Friday, July 2015 2015-1998 Difference

Source Category Metric Tons 

per Day

Metric Tons 

per Day

Percent

Point 15.6 21.0 34.6

Area 91.9 152.1 65.5

Nonroad Mobile 76.2 27.9 -63.4

Onroad Mobile 103.5 46.3 -55.3

Biogenics 85.5 93.7 9.6

Total 372.7 341.0 -8.5
3-11

TABLE 3-5

SUMMARY OF NOX EMISSIONS FOR AUGUST EPISODE IN 1999 BASE CASE,

AND 2006 AND 2015 WITH COMMITTED MAINTENANCE MEASURES

Tuesday, 

August 24, 1999

Tuesday, 

August 2006

Tuesday, 

August 2015

2006-1999

Difference

2015-1999

Difference

Source

Category

Metric Tons 

per Day

Metric Tons 

per Day

Metric Tons 

per Day

Percent Percent

Point 16.5 24.5 26.3 48.5 59.4

Area 43.0 54.1 67.4 25.8 56.7

Nonroad

Mobile

59.3 50.9 57.2 -14.2 -3.5

Onroad

Mobile

129.8 104.8 53.6 -19.3 -58.7

Biogenics 7.3 7.1 6.2 -2.7 -15.1

Total 255.9 241.4 210.7 -5.7 -17.7
3-12

TABLE 3-6

SUMMARY OF VOC EMISSIONS FOR AUGUST EPISODE IN 1999 BASE CASE,

AND 2006 AND 2015 WITH COMMITTED MAINTENANCE MEASURES

Tuesday, 

August 24, 1999

Tuesday, 

August 2006

Tuesday, 

August 2015

2006-1999

Difference

2015-1999

Difference

Source

Category

Metric Tons 

per Day

Metric Tons 

per Day

Metric Tons 

per Day

% %

Point 15.3 17.4 20.2 13.7 32.0

Area 82.6 101.4 123.5 22.8 49.5

Nonroad

Mobile

78.5 61.0 28.7 -22.3 -63.4

Onroad

Mobile

106.9 71.9 48.7 -32.7 -54.4

Biogenics 76.7 77.2 85.8 0.7 11.9

Total 360.0 328.9 306.9 -8.6 -14.8
3-13

Next to the forest vegetation types, the “Residential” land use category has the highest

emission factors for biogenic VOC emissions. On the other hand, the “Agriculture” land

use type is the biggest contributor to biogenic NOx emissions. Since it is anticipated that

residential area will continue to increase and agriculture area is expected to decline over

time, biogenic VOC emissions increase by about 0.7 percent between 1999 and 2006, and

about 12 percent between 1999 and 2015, while biogenic NOx emissions decrease by

about 3 percent between 1999 and 2006, and about 15 percent between 1999 and 2015.

With implementation of the committed maintenance measures, total NOx emissions

decrease by 5.7 percent between 1999 and 2006 and 17.7 percent between 1999 and

2015. Total VOC emissions decrease by 8.6 percent between 1999 and 2006 and 14.8

percent between 1999 and 2015.

MAINTENANCE DEMONSTRATION

To demonstrate maintenance of the one-hour ozone NAAQS, the results from the urban

airshed modeling analyses should not show predicted one-hour maximum ozone

concentrations equivalent to or greater than 0.125 ppm anywhere in the modeling domain

for the episode modeled. The maintenance demonstration follows the deterministic

procedure prescribed in the EPA Guideline. 

UAM Analysis

The purpose of future year simulations is to illustrate the effects of projected emission

changes on simulated air quality for given episodes. Comparison of the base and future

year emission totals, as shown in Tables 3-3 through 3-6, indicates that total NOx

emissions for 2015 are 21 percent and 18 percent lower than the 1998 and 1999 emissions

estimates, respectively. Total VOC emissions for 2015 are 9 percent and 15 percent lower

than the 1998 and 1999 emissions estimates, respectively. The Base Case Input

Preparation, Quality Assurance and Diagnostic Analyses, and Performance Evaluation for

the UAM runs are documented in Sections III, VI, and V, respectively, of the Ozone

Maintenance Plan Technical Support Document.

UAM Results

The 1998, 1999, 2006, and 2015 maximum simulated ozone one-hour concentrations and

the grid cells where the maximum ozone concentrations occurred are provided in

Table 3-7. As shown, the simulated one-hour ozone concentrations for both July and

August episodes are below 125 ppb everywhere in the modeling domain for both 2006 and

2015. Therefore, the modeling results showed maintenance of the NAAQS for ozone in

2006 and 2015 for the Maricopa County nonattainment area. 

MOBILE SOURCE EMISSIONS BUDGETS FOR OZONE

In accordance with the 1990 Clean Air Act Amendments, conformity requirements are

intended to ensure that transportation activities do not result in air quality degradation.

Section 176 of the Amendments requires that transportation plans, programs, and projects

conform to applicable air quality plans before the transportation action is approved by a

Metropolitan Planning Organization (MPO). The designated MPO for the Maricopa County

area is MAG.
3-14

TABLE 3-7

THE 1998, 1999, 2006 AND 2015 MAXIMUM SIMULATED ONE-HOUR OZONE 

CONCENTRATIONS FOR BOTH THE JULY AND AUGUST EPISODES

Modeled Episode

Regional Maximum Simulated 

One-hour Concentration (ppb) Location

July 1998 119 (41,30)

August 1999 125 (53,28)

August 2006 124 (52,30)

July 2015 116 (45,35)

August 2015 120 (51,30)
3-15

Section 176(c) of CAAA provides the framework for ensuring that Federal actions conform

to air quality plans under Section 110. Conformity to an implementation plan means that

proposed activities must not (1) cause or contribute to any new violation of any standard

in any area, (2) increase the frequency or severity of any existing violation of any standard

in any area, or (3) delay timely attainment of any standard or any required interim emission

reductions or other milestones in any area. 

EPA transportation conformity regulations establish criteria involving comparison of

projected transportation plan emissions with the motor vehicle emissions assumed in

applicable air quality plans. The regulations define the term “motor vehicle emissions

budget” as meaning “the portion of the total allowable emissions defined in a revision of

the applicable implementation plan (or in an implementation plan revision which was

endorsed by the Governor or his or her designee) for a certain date for the purpose of

meeting reasonable further progress milestones or attainment or maintenance

demonstrations, for any criteria pollutant or its precursors, allocated by the applicable

implementation plan to highway and transit vehicles.”

The transportation conformity budget for Volatile Organic Compounds (VOCs) was

established in the EPA approved and promulgated Revised Rate of Progress Federal

Implementation Plan (FIP), effective August 5, 1999. This FIP established a motor vehicle

emissions budget for VOCs of 87.1 metric tons for an average summer (ozone) season

day. This budget will be used in MAG transportation conformity analyses until the

Maintenance Plan is approved or the maintenance budget is found to be adequate. At that

time, new transportation conformity budgets for VOC and NOx will be established for 2006

and 2015 for use in subsequent conformity analyses. 

Onroad mobile source emissions for 2006 and 2015 were developed by MAG using the

EPA-approved MOBILE6 model and Highway Performance Monitoring System (HPMS)

reconciliation methodology. Documentation of the HPMS reconciliation methodology and

an EPA approval letter are contained in Appendix III-iv of TSD. After the new motor vehicle

emissions budgets are approved by EPA for conformity purposes, MAG will apply

MOBILE6 and the HPMS reconciliation procedure to estimate onroad mobile source

emissions for all conformity horizon years.

The projections of the primary episode (a Tuesday in August) in this Maintenance Plan

indicate that total NOx emissions in 2006 and 2015 would be 241.4 and 210.7 metric tons

per day, respectively, with the committed maintenance measures. The onroad mobile

source contribution for NOx is 104.8 metric tons per day in 2006 and 53.6 metric tons per

day in 2015 (from Table 3-5). Table 3-6 shows that total VOC emissions in 2006 and 2015

would be 328.9 and 306.9 metric tons per day, respectively, with the committed

maintenance measures, which includes an onroad mobile source contribution for VOCs

of 71.9 metric tons per day in 2006 and 48.7 metric tons per day in 2015. The total onroad

mobile source emissions of 53.6 metric tons per day for NOx and 48.7 metric tons per day

for VOCs represent the conformity budgets for ozone precursors in 2015. Since 2006 was

also modeled, the Maintenance Plan establishes interim conformity budgets of 104.8

metric tons per day for NOx and 71.9 metric tons per day for VOCs in 2006. The 2006 and
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2015 emission inventories used to establish the mobile source emissions budgets are

documented in Appendix VI of the Technical Support Document.

After EPA finds the maintenance budgets to be adequate or approves the Maintenance

Plan, MAG will apply the provisions of the EPA transportation conformity regulations

(August 15, 1997), 40 CFR Part 93 Section 93.118(b). This Maintenance Plan establishes

motor vehicle emissions budgets for the maintenance year of 2015 and the interim year

of 2006. In accordance with 40 CFR Part 93 Section 93.118(b), MAG will use the new

interim 2006 mobile source VOC and NOx emissions budgets for the conformity horizon

years of 2006 through 2014 and the new 2015 mobile source ozone precursor emissions

budgets for conformity horizon years after 2014. 

MONITORING NETWORK / VERIFICATION OF CONTINUED ATTAINMENT

Air quality monitoring data in Maricopa County confirm that the attainment date of

November 15, 1999, was met, since no violation of the one-hour ozone standard has

occurred at any monitor since 1996. As a result, on May 30, 2001, EPA published a final

rulemaking notice determining that the Phoenix metropolitan serious ozone nonattainment

area has attained the one-hour ozone air quality standard by the Clean Air Act deadline of

November 15, 1999.

Once the Maricopa County Nonattainment Area has been redesignated to attainment

status by EPA, the Arizona Department of Environmental Quality (ADEQ) and the Maricopa

County Environmental Services Department (MCESD) will continue to operate an

appropriate air quality monitoring network of National Air Monitoring Stations (NAMS) and

State and Local Air Monitoring Stations (SLAMS) monitors in accordance with 40 CFR Part

58 to verify the continued attainment of the ozone standard. If measured mobile source

parameters (e.g., vehicle miles traveled, congestion, fleet mix, etc.) change significantly

over time, ADEQ and MCESD will perform the appropriate studies to determine whether

additional and/or re-sited monitors are necessary. Annual review of the NAMS/SLAMS air

quality surveillance system will be conducted in accordance with 40 CFR 58.20(d) to

determine whether the system continues to meet the monitoring objectives presented in

Appendix D of 40 CFR Part 58.

In order to track the progress of the Maintenance Plan, periodic emission inventories will

also be prepared every three years in accordance with Section 187(a)(5) of the Clean Air

Act. Maricopa County will coordinate and compile the inventory with input and assistance

from the Arizona Department of Environmental Quality, Arizona Department of

Transportation, and Maricopa Association of Governments, as described in the 1992 Air

Quality Memorandum of Agreement. Changes in the inventory will be reviewed and

evaluated through the regional air quality planning process to determine if additional

measures should be considered. 

The final 1999 Periodic Ozone Emissions Inventory was prepared by the Maricopa County

Environmental Services Department in August 2002 and is provided in the Appendices.

Work has begun on the 2002 periodic ozone emissions inventory and the Maricopa County
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Environmental Services Department expects to complete the inventory by the second

quarter of 2004. 

CONTINGENCY PROVISIONS

Section 175A(d) of the Clean Air Act requires that maintenance plans contain contingency

provisions. EPA guidance on the required content of the contingency plan is provided in

the September 4, 1992 EPA memorandum. This memo indicates that the contingency plan

is not required to contain fully adopted contingency measures. However, the plan should

contain clearly identified contingency measures to be adopted, a schedule and procedure

for adoption and implementation, and a specific time limit for action by the State. In

addition, specific indicators should be identified which will be used to determine when the

contingency measures need to be implemented. The Maintenance Plan addresses each

of these requirements for an approvable contingency plan.

Consistent with the August 13, 1993 EPA guidance memorandum titled, “Early

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

Nonattainment Areas,” the contingency plan described in the maintenance plan is

comprised of committed control measures that are expected to be implemented early.

Early implementation of contingency measures in a maintenance plan has been approved

by EPA in the redesignation of the Salt Lake City Carbon Monoxide Nonattainment Area

to attainment (see page 3216 of the January 21, 1999 Federal Register). In that action,

EPA noted that both contingency measures in the Salt Lake City Contingency Plan had

already been partially implemented.

The three contingency measures in the Maintenance Plan are Area A Expansion, Gross

Polluter Option for I/M Program Waivers, and Increased Waiver Repair Limit Options.

Emissions reduction credit for these contingency measures was not taken in the

maintenance demonstration.

 

A description of these individual measures is provided in Section VI of the Technical

Support Document. Early implementation of these contingency measures provides

additional confidence that the one-hour ozone standard will be maintained through 2015.

The success of an air quality program is measured by the concentrations recorded at the

monitors. EPA regulations (see 40 CFR 50.9 and Appendix H to 40 CFR 50) define an

exceedance of the one-hour ozone standard as a daily maximum hourly average ozone

measurement greater than 0 .12 ppm. Values from 0.121 ppm to 0.124 ppm are rounded

down to 0.12 ppm and thus, an exceedance is a daily maximum hourly average that is

equal to or greater than 0.125 ppm. A violation of the NAAQS for one-hour ozone occurs

when the expected number of exceedances per calendar year at any ozone monitoring

site, averaged over the past three calendar years, is greater than 1.0.

In order to ensure that violations of the one-hour ozone standard do not occur in the future,

ambient air quality monitoring data will be examined to determine if additional contingency

measures are needed. Contingency provisions will be triggered when the fourth highest
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daily maximum hourly measurement over the past three years exceeds 0.120 ppm at any

ozone monitor. If this occurs, additional measures will be considered, which may include

the strengthening of existing contingency measures. This trigger is more stringent than the

standard and will serve to prevent the occurrence of future violations. When activated,

additional control measures would be considered on the following schedule: (A)

verification of the monitoring data to be completed three months after activation of the

trigger; (B) applicable measure to be considered for adoption six months after date

established in A above; and (C) resultant committed measure to be implemented within six

to twelve months, depending upon the time needed to put the measure in place.

SUBSEQUENT MAINTENANCE PLAN REVISIONS

It is required that a maintenance plan revision be submitted to the EPA eight years after

the original redesignation request/maintenance plan is approved. The purpose of this

revision is to provide for maintenance of the ozone NAAQS for an additional ten years

following the first ten-year period. As the designated Regional Air Quality Planning Agency

for the Maricopa County area, the Maricopa Association of Governments intends to

prepare a revised maintenance plan eight years after redesignation to attainment, as

required by the Clean Air Act and the Environmental Protection Agency.