federal register

Tuesday

October 27, 1998

Part II

Environmental

Protection Agency

40 CFR Parts 51, 72, 75, and 96

Finding of Significant Contribution and

Rulemaking for Certain States in the

Ozone Transport Assessment Group

Region for Purposes of Reducing

Regional Transport of Ozone; Rule
57356 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 51, 72, 75, and 96

[FRL–6171–2]

RIN 2060–AH10

Finding of Significant Contribution and

Rulemaking for Certain States in the

Ozone Transport Assessment Group

Region for Purposes of Reducing

Regional Transport of Ozone

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: In accordance with the Clean

Air Act (CAA), today’s action is a final

rule to require 22 States and the District

of Columbia to submit State

implementation plan (SIP) revisions to

prohibit specified amounts of emissions

of oxides of nitrogen (NOX)—one of the

precursors to ozone (smog) pollution—

for the purpose of reducing NOX and

ozone transport across State boundaries

in the eastern half of the United States.

Ground-level ozone has long been

recognized, in both clinical and

epidemiological research, to affect

public health. There is a wide range of

ozone-induced health effects, including

decreased lung function (primarily in

children active outdoors), increased

respiratory symptoms (particularly in

highly sensitive individuals), increased

hospital admissions and emergency

room visits for respiratory causes

(among children and adults with preexisting respiratory disease such as

asthma), increased inflammation of the

lung, and possible long-term damage to

the lungs.

In today’s action, EPA finds that

sources and emitting activities in each

of the 22 States and the District of

Columbia (23 jurisdictions) emit NOX in

amounts that significantly contribute to

nonattainment of the 1-hour and 8-hour

ozone national ambient air quality

standards (NAAQS), or will interfere

with maintenance of the 8-hour

NAAQS, in one or more downwind

States. Further, by today’s action, EPA

is requiring each of the affected upwind

jurisdictions (sometimes referred to as

upwind States) to submit SIP revisions

prohibiting those amounts of NOX

emissions which significantly

contribute to downwind air quality

problems. The reduction of those NOX

emissions will bring NOX emissions in

each of those States to within the

resulting statewide NOX emissions

budget levels established in today’s rule.

The 23 jurisdictions are: Alabama,

Connecticut, Delaware, District of

Columbia, Georgia, Illinois, Indiana,

Kentucky, Massachusetts, Maryland,

Michigan, Missouri, North Carolina,

New Jersey, New York, Ohio,

Pennsylvania, Rhode Island, South

Carolina, Tennessee, Virginia, West

Virginia, and Wisconsin. These States

will be able to choose any mix of

pollution-reduction measures that will

achieve the required reductions.

EFFECTIVE DATES: This rule is effective

December 28, 1998. The incorporation

by reference of certain publications

listed in the regulations is approved by

the Director of the Federal Register as of

December 28, 1998.

ADDRESSES: Dockets containing

information relating to this rulemaking

(Docket No. A–96–56 and Docket No.

A–9–35) are available for public

inspection at the Air and Radiation

Docket and Information Center (6102),

US Environmental Protection Agency,

401 M Street SW, room M–1500,

Washington, DC 20460, telephone (202)

260–7548, between 8:00 a.m. and 4:00

p.m., Monday through Friday, excluding

legal holidays. A reasonable fee may be

charged for copying.

FOR FURTHER INFORMATION CONTACT:

General questions concerning today’s

action should be addressed to Kimber S.

Scavo, Office of Air Quality Planning

and Standards, Air Quality Strategies

and Standards Division, MD–15,

Research Triangle Park, NC 27711,

telephone (919) 541–3354; e-mail:

scavo.kimber@epa.gov. Please refer to

SUPPLEMENTARY INFORMATION below for a

list of contacts for specific subjects

described in today’s action.

SUPPLEMENTARY INFORMATION:

Availability of Related Information

Documents related to the Ozone

Transport Assessment Group (OTAG)

are available on the Agency’s Office of

Air Quality Planning and Standards’

(OAQPS) Technology Transfer Network

(TTN) via the web at http://

www.epa.gov/ttn/. If assistance is

needed in accessing the system, call the

help desk at (919) 541–5384 in Research

Triangle Park, NC. Documents related to

OTAG can be downloaded directly from

OTAG’s webpage at http://

www.epa.gov/ttn/otag/. The OTAG’s

technical data are located at http://

www.iceis.mcnc.org/OTAGDC. The

notice of proposed rulemaking for this

final action, the supplemental notice of

proposed rulemaking, and associated

documents are located at http://epa.gov/

ttn/oarpg/otagsip.html. Information

related to Sections II, Weight of

Evidence Determination of Covered

States, and IV, Air Quality Assessment,

can be obtained in electronic form from

the following EPA website: http://

www.epa.gov/scram001/regmodcenter/

t28.htm. Information related to Section

III, Determination of Budgets, may be

found on the following EPA website:

http://www.epa.gov/capi. All

information in electronic form may also

be found on diskettes that have been

placed in the docket to this rulemaking.

For Additional Information

For technical questions related to the

air quality analyses, please contact

Norm Possiel; Office of Air Quality

Planning and Standards; Emissions,

Monitoring, and Analysis Division; MD–

14, Research Triangle Park, NC 27711,

telephone (919) 541–5692. For legal

questions, please contact Howard J.

Hoffman, Office of General Counsel, 401

M Street SW, MC–2344, Washington,

DC 20460, telephone (202) 260–5892.

For questions concerning the statewide

emissions budget revisions, please

contact Laurel Schultz; Office of Air

Quality Planning and Standards;

Emissions, Monitoring, and Analysis

Division; MD–14, Research Triangle

Park, NC 27711, telephone (919) 541–

5511. For questions concerning SIP

reporting requirements, please contact

Bill Johnson, Office of Air Quality

Planning and Standards, Air Quality

Strategies and Standards Division, MD–

15, Research Triangle Park, NC 27711,

telephone (919) 541–5245. For questions

concerning the model cap-and-trade

rule, please contact Rob Lacount, Office

of Atmospheric Programs, Acid Rain

Division, MC–6204J, 401 M Street SW,

Washington, DC 20460, telephone (202)

564–9122. For questions concerning the

regulatory cost analysis of electricity

generating sources, please contact Ravi

Srivastava, Office of Atmospheric

Programs, Acid Rain Division, MC–

6204J, 401 M Street SW, Washington DC

20460, telephone (202) 564–9093. For

questions concerning the regulatory cost

analysis of other stationary sources and

questions concerning the Regulatory

Impact Analysis (RIA), please contact

Scott Mathias, Office of Air Quality

Planning and Standards, Air Quality

Strategies and Standards Division, MD–

15, Research Triangle Park, NC 27711,

telephone (919) 541–5310.

Outline

I. Background

A. Summary of Rulemaking and Affected

States

B. General Factual Background

C. Statutory and Regulatory Background

1. CAA Provisions

a. 1970 and 1977 CAA Amendments

b. 1990 CAA Amendments

2. Regulatory Structure

a. March 2, 1995 Policy

b. OTAG
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57357

c. EPA’s Transport SIP Call Regulatory

Efforts

d. Revision of the Ozone NAAQS

D. Section 126 Petitions

E. OTAG

F. Discussion of Comment Period and

Availability of Key Information

1. Request for Extension of the Comment

Period

2. Request for Time to Conduct Additional

Modeling

3. Availability of Key Information

4. Public Hearings

G. Implementation of Revised Air Quality

Standards

H. Summary of Major Changes between

Proposals and Final Rule

1. EPA’s Analytical Approach (Section

II.A)

2. Cost Effectiveness of Emissions

Reductions (Section II.D)

3. Determination of Budgets (Section III)

4. NOX Control Implementation and

Budget Achievement Dates (Section V)

5. SIP Criteria (Section VI.A)

6. Emissions Reporting Requirements for

States (Section VI.B)

7. NOX Budget Trading Program (Section

VII)

8. Interaction with Title IV NOX Rule

(Section VIII)

9. Administrative Requirements (Section

X)

II. EPA’s Analytical Approach

A. Interpretation of the CAA’s Transport

Provisions

1. Authority and Process for Requiring SIP

Submissions under the 1-Hour Ozone

NAAQS

a. Authority for Requiring SIP Submissions

under the 1-Hour NAAQS

b. Process for Requiring SIP Submissions

under the 1-Hour NAAQS

2. Authority and Process for Requiring SIP

Submissions under the 8-Hour Ozone

NAAQS

a. Authority for Requiring SIP Submissions

under the 8-Hour NAAQS

b. Process for Requiring SIP Submissions

under the 8-hour Standard

3. Requirements of Section 110(a)(2)(D)

a. Summary

b. Determination of Meaning of

‘‘Nonattainment’

c. Definition of Significant Contribution

d. Multi-factor Test for Determining

Significant Contribution

e. Air Quality Factors

f. Determination of Highly Cost-effective

Reductions and of Budgets

g. Other Considerations in Determination

of Significant Contribution

h. Interfere with Maintenance

i. Dates

j. Downwind Areas’ Control Obligations

k. Section 110(a)(2)(D) Caselaw

B. Alternative Interpretation of Section

110(a)(2)(D)

C. Weight-of-Evidence Determination of

Covered States

1. Major Findings from OTAG-Related

Technical Analyses

2. Summary of Notice of Proposed

Rulemaking Weight-of-Evidence

Approach

a. Quantification of Contributions

b. Evaluation of 1-Hour and 8-Hour

Contributions

c. Comments and Responses on Proposed

Weight-of-Evidence Approach to

Significant Contribution

3. Analysis of State-specific Air Quality

Factors

a. Overall Nature of Ozone Problem

(‘‘Collective Contribution’’)

b. Extent of Downwind Nonattainment

Problems

c. Air Quality Impacts of Upwind

Emissions on Downwind Nonattainment

4. Confirmation of States Making a

Contribution to Downwind

Nonattainment

a. Analysis Approach

b. States Which Contain Sources That

Significantly Contribute to Downwind

Nonattainment

c. Examples of Contributions From

Upwind States to Downwind

Nonattainment

d. Conclusions From Air Quality

Evaluation of Downwind Contributions

5. States Not Covered by This Rulemaking

D. Cost Effectiveness of Emissions

Reductions

1. Sources Included in the CostEffectiveness Determination

a. Electricity Generating Boilers and

Turbines

b. Other Stationary Sources

2. Sources Not Included in the CostEffectiveness Determination

a. Area Sources

b. Small Point Sources

c. Mobile Sources

d. Other Stationary Sources

e. Conclusion

E. Other Considerations

1. Consistency of Regional Reductions with

Attainment Needs of Downwind Areas

a. General Discussion

b. 8-hour Nonattainment Problems

c. Commenters’ Concerns

2. Equity Considerations

3. General Cost Considerations

4. Conclusion

III. Determination of Budgets

A. General Comments on the Base

Emission Inventory

1. Quality

2. Availability

B. Electricity Generating Units (EGUs)

1. Base Inventory

2. Growth

a. Growth Rates

b. Use of IPM

c. Use of ‘‘Corrected’’ Growth Rates

3. Budget Calculation

a. Input vs. Output

b. Alternative Emission Limits

c. Consideration of the Climate Change

Action Plan

C. Non-EGU Point Sources

1. Base Inventory

2. Growth

3. Budget Calculation

a. Proposed Control Assumptions

b. Small Source Exemption

c. Exemptions for Other Non-EGU Point

Sources

d. Sources Without Adequate Control

Information

e. Case-By-Case Analysis of Control

Measures

f. Cost Effectiveness

g. Industrial Boiler Control Costs

h. Cement Manufacturing

i. Stationary Internal Combustion Engines

j. Industrial Boilers and Turbines

k. Municipal Waste Combustors (MWCs)

D. Highway Mobile Sources

1. Base Inventory

2. Growth

3. Budget Calculation

a. I/M Program Coverage

b. Emissions Cap

c. Tier 2 Standards

d. Low Sulfur Fuel

e. Conformity

E. Stationary Area and Nonroad Mobile

Sources

1. Base Inventory

2. Growth

3. Budget Calculation

F. Other Budget Issues

1. Uniform vs. Regional Controls

2. Seasonal vs. Annual Controls

3. Full vs. Partial States

4. NOx Waivers

5. Recalculation of Budgets

6. Compliance Supplement Pool

a. Size of the Compliance Supplement Pool

b. State Distribution of the Compliance

Supplement Pool

7. Banking

a. Banking Starting in 2003

b. Management of Banked Allowances

c. Early Reduction Credits

G. Final Statewide Budgets

1. EGU

a. Description of Selected Approach

b. Summary of Budget Component

2. Non-EGU Point Sources

a. Description of Selected Approach

b. Summary of Budget Component

3. Mobile and Area Sources

a. Description of Selected Budget

Approach

b. Summary of Budget Component

4. Potential Alternatives to Meeting the

Budget

5. Statewide Budgets

IV. Air Quality Assessment

A. Assessment of Proposed Statewide

Budgets

B. Comments and Responses

C. Assessment of Alternative Control

Levels

1. Scenarios Modeled

2. Emissions for Model Runs

3. Modeling Results

a. Impacts of Alternative Controls

b. Impacts of Upwind Controls on

Downwind Nonattainment

c. Summary of Findings

V. NOx Control Implementation and Budget

Achievement Dates

A. NOx Control Implementation Date

1. Practicability

a. Combustion Controls

b. Post-Combustion Controls

2. Relationship to SIP Submittal Date

3. Rationale

B. Budget Achievement Date

VI. SIP Criteria and Emissions Reporting

Requirements

A. SIP Criteria

1. Schedule for SIP Revision

2. Approvability Criteria

a. Source Categories Subject to Additional

Approvability Criteria
57358 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

b. Pollution Abatement Requirements

c. Monitoring Requirements

d. Approvability of Trading Program

3. Sanctions

4. FIPs

B. Emissions Reporting Requirements for

States

1. Use of Inventory Data

2. Response to Comments

3. Final Rule

4. Data Elements to be Reported

5. 2007 Report

6. Ozone Season Reporting

7. Data Reporting Procedures

8. Confidential Data

C. Timeline

VII. NOX Budget Trading Program

A. General Background

B. NOX Budget Trading Program

Rulemaking Overview

C. General Design of NOX Budget Trading

Program

1. Appropriateness of Trading Program

2. Alternative Market Mechanisms

3. State Adoption of Model Rule

a. Process for Adoption

b. Model Rule Variations

4. Unrestricted Trading Market

a. Geographic Issues

b. Episodic Issues

D. Applicability

1. Core Sources

a. Commenters Who Felt the Core Group

Should Not Be Changed

b. Commenters Who Felt the Core Group

Should Be Expanded

c. Commenters Who Felt the Core Group Is

Overly Inclusive

2. Mobile/Area Sources

3. Monitoring

a. Use of Part 75 to Ensure Compliance

with the NOX Budget Trading Program

b. Use of CEMS on Large Units

c. Commenters Who do not Believe that

CEMS are Necessary

d. Issues Related to Monitoring and

Reporting Needed to Support a Heat

Input Allocation Methodology

e. Amendments to Part 75

E. Emission Limitations/Allowance

Allocations

1. Timing Requirements

2. Options for NOX Allowance Allocation

Methodology

3. New Source Set-Aside

4. Optional NOX Allocation Methodology

in Model Rule

F. Banking Provisions

1. Banking Starting in 2003

2. Management of Banked Allowances

3. Early Reduction Credits

4. Optional Methodology for Issuing Early

Reduction Credits

5. Integrating the OTC Program with the

NOX Budget Trading Program’s Banking

Provisions

G. New Source Review

VIII. Interaction with Title IV NOX Rule

IX. Non-Ozone Benefits of NOX Emissions

Decreases

A. Summary of Comments

B. Response to Comments

1. Drinking Water Nitrate

2. Eutrophication

3. Regulatory Impact Analysis

4. Justification for Rulemaking

X. Administrative Requirements

A. Executive Order 12866: Regulatory

Impact Analysis

B. Regulatory Flexibility Act: Small Entity

Impacts

C. Unfunded Mandates Reform Act

D. Paperwork Reduction Act

E. Executive Order 13045: Protection of

Children from Environmental Health

Risks and Safety Risks

1. Applicability of E.O. 13045

2. Children’s Health Protection

F. Executive Order 12898: Environmental

Justice

G. Executive Order 12875: Enhancing the

Intergovernmental Partnerships

H. Executive Order 13084: Consultation

and Coordination with Indian Tribal

Governments

I. Judicial Review

J. Congressional Review Act

K. National Technology Transfer and

Advancement Act

Appendix A—Detailed Discussion of

Changes to Part 75

CFR Revisions and Additions

Part 51

§ 51.121

§ 51.122

Part 72

Part 75

Part 96

I. Background

A. Summary of Rulemaking and

Affected States

By notice of proposed rulemaking

(NPR, proposal, or ‘‘proposed SIP call’’)

(62 FR 60318, November 7, 1997) and by

supplemental notice (SNPR or

supplemental proposal) (63 FR 25902,

May 11, 1998), EPA proposed to find

that NOX emissions from sources and

emitting activities (sources) in 23

jurisdictions (hereinafter also referred to

as States) will significantly contribute to

nonattainment of the 1-hour and 8-hour

ozone NAAQS, or will interfere with

maintenance of the 8-hour NAAQS, in

one or more downwind States

throughout the Eastern United States.

The EPA based these proposals on data

generated by OTAG, public comments,

and other relevant information. Today’s

final action confirms that proposed

finding. It also requires, under CAA

section 110(a)(1) and 110(k)(5), that the

23 jurisdictions adopt and submit SIP

revisions that, in order to assure that

their SIPs meet the requirements of

section 110(a)(2)(D)(i)(I), contain

provisions adequate to prohibit sources

in those States from emitting NOX in

amounts that ‘‘contribute significantly

to nonattainment in, or interfere with

maintenance by,’’ a downwind State.

The 23 jurisdictions are: Alabama,

Connecticut, Delaware, District of

Columbia, Georgia, Illinois, Indiana,

Kentucky, Massachusetts, Maryland,

Michigan, Missouri, North Carolina,

New Jersey, New York, Ohio,

Pennsylvania, Rhode Island, South

Carolina, Tennessee, Virginia, West

Virginia, and Wisconsin.

Each of these States and the District

of Columbia is required to adopt and

submit by September 30, 1999, a SIP

revision. The SIP revision must contain

measures that will assure that sources in

the State reduce their NOX emissions

sufficiently to eliminate the amounts of

NOX emissions that contribute

significantly to nonattainment, or that

interfere with maintenance, downwind.

By eliminating these amounts of NOX

emissions, the control measures will

assure that the remaining NOX

emissions will meet the level identified

in today’s rule as the State’s NOX

emissions budget. For simplicity, this

final rule may refer to the amounts that

such SIP provisions must prohibit in

order to meet the statute as the

‘‘significant amounts’’ of NOX

emissions. After prohibiting these

significant amounts of NOX, the

remaining amounts emitted by sources

in the covered States will not

‘‘significantly contribute to

nonattainment, or interfere with

maintenance by,’’ a downwind State,

under section 110(a)(2)(D)(i)(I). Section

II.C, Weight-of-Evidence Determination

of Covered States, describes how EPA

determined which States include

sources that emit NOX in amounts of

concern (the ‘‘covered’’ States), and

Sections II.D, Cost Effectiveness of

Emissions Reductions; II.E, Comparison

of Upwind and Downwind Costs; and

III, Determination of Budgets, describe

how EPA determined the significant

amounts of emissions and the resulting

statewide emissions budgets for the

States identified above. Section IV, Air

Quality Assessment, discusses air

quality analyses conducted by EPA

which help confirm the decisions and

requirements set forth in this

rulemaking. Section V, NOX Control

Implementation and Budget

Achievement Dates, primarily discusses

the dates by which (1) the States must

submit SIP revisions in response to

today’s action, (2) the sources must

implement the measures the States

choose for the purpose of prohibiting

the significant amounts of NOX, and (3)

the States are projected to achieve the

budget levels. Section VI, SIP Criteria

and Emissions Reporting Requirements,

describes the SIP requirements

themselves.

The SIP requirements permit each

State to determine what measures to

adopt to prohibit the significant

amounts and hence meet the necessary

emissions budget. Consistent with

OTAG’s recommendations to achieve
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57359

NOX emissions decreases primarily from

large stationary sources in a trading

program, EPA encourages States to

consider electric utility and large boiler

controls under a cap-and-trade program

as a cost-effective strategy. The

recommended cap-and-trade program is

described in more detail in Section VII,

NOX Budget Trading Program. The EPA

also recognizes that promotion of energy

efficiency can contribute to a costeffective strategy. In Section VIII,

Interaction with Title IV NOX rule, EPA

explains that it is not adopting proposed

revisions to the title IV NOX rule

concerning the relationship between

this rulemaking and the title IV NOX

rule. The remaining parts of today’s

action include Section IX, Non-Ozone

Benefits of NOX Reductions, and

Section X, Administrative

Requirements.

The EPA also conducted a RIA which

is available in the docket to this

rulemaking as a technical support

document (TSD), entitled ‘‘Regulatory

Impact Analysis for the Regional NOX

SIP Call’’ (docket no. VI–B–09). A

detailed explanation of how EPA

calculated the budgets is also available

as a TSD entitled ‘‘Development of

Modeling Inventory and Budgets for the

Regional NOX SIP Call’’ (docket no. VI–

B–10). These two TSDs have been

revised for the final rulemaking. A

detailed explanation of the air quality

modeling analyses is also available,

entitled ‘‘Air Quality Modeling

Technical Support Document for the

Regional NOX SIP Call’’ (docket no. VI–

B–11) for this final rulemaking. This

preamble for today’s notice responds to

some of the comments, but another

document, entitled ‘‘Response to

Significant Comments on the Finding of

Significant Contribution and

Rulemaking for Certain States in the

OTAG Region for Purposes of Reducing

Regional Transport of Ozone,’’ is

included in the docket (docket no. VI–

C–01).

B. General Factual Background

In today’s action, EPA takes a

significant step toward reducing ozone

in the eastern half of the country.

Ground-level ozone, the main harmful

ingredient in smog, is produced in

complex chemical reactions when its

precursors, volatile organic compounds

(VOC) and NOX, react in the presence of

sunlight. The chemical reactions that

create ozone take place while the

pollutants are being blown through the

air by the wind, which means that

ozone can be more severe many miles

away from the source of emissions than

it is at the source.

The science of ozone formation,

transport, and accumulation is complex.

Ozone is produced and destroyed in a

cyclical set of chemical reactions

involving NOX, VOC and sunlight.

Emissions of NOX and VOC are

necessary for the formation of ozone in

the lower atmosphere. In part of the

cycle of reactions, ozone concentrations

in an area can be lowered by the

reaction of nitric oxide with ozone,

forming nitrogen dioxide; as the air

moves downwind and the cycle

continues, the nitrogen dioxide forms

additional ozone. The importance of

this reaction depends, in part, on the

relative concentrations of NOX, VOC

and ozone, all of which change with

time and location.

At ground level, ozone can cause a

variety of ill effects to human health,

crops and trees. Specifically, groundlevel ozone has been shown in clinical

and/or epidemiologial studies to have

the following health effects:

fl Decreased lung function, primarily in

children active outdoors

fl Increased respiratory symptoms,

particularly in highly sensitive individuals

fl Hospital admissions and emergency

room visits for respiratory causes among

children and adults with pre-existing

respiratory disease such as asthma

fl Inflammation of the lung

fl Possible long-term damage to the lungs

or even premature death.

The new 8-hour primary ambient air

quality standard (62 FR 38856, July 18,

1997) will provide increased protection

to the public from these health effects.

Each year, ground-level ozone above

background is also responsible for

significant agricultural crop yield losses.

Ozone also causes noticeable foliar

damage in many crops, trees, and

ornamental plants (i.e., grass, flowers,

shrubs, and trees) and causes reduced

growth in plants. Studies indicate that

current ambient levels of ozone are

responsible for damage to forests and

ecosystems (including habitat for native

animal species).

As part of the efforts to reduce

harmful levels of smog, EPA, today, is

establishing a requirement for certain

States to revise their SIPs in order to

implement the necessary regional-scale

reductions in NOX emissions, and,

thereby, reduce transported NOX and

ozone. Since air pollution travels across

county and State lines, it is essential for

State governments and air pollution

control agencies to cooperate to solve

the problem.

Currently, the following areas,

impacted by the 23 jurisdictions that are

the subject of today’s rulemaking, are

designated nonattainment areas for

ozone under the 1-hour NAAQS:

Atlanta, GA

Baltimore, MD

Birmingham, AL

Boston-Lawrence-Worcester (eastern MA),

MA–NH

Chicago-Gary-Lake County, IL–IN

Cincinnati-Hamilton, OH–KY

Door County, WI

Greater Connecticut

Kent & Queen Anne’s Counties, MD

Lancaster, PA

Louisville, KY–IN

Manitowoc County, WI

Milwaukee-Racine, WI

Muskegon, MI

New York-Northern New Jersey-Long Island,

NY–NJ–CT

Philadelphia-Wilmington-Trenton, PA–NJ–

DE–MD

Pittsburgh-Beaver Valley, PA

Portland, ME

Portsmouth-Dover-Rochester, NH

Providence (All RI), RI

St. Louis, MO–IL

Springfield (western MA), MA

Washington, DC–MD–VA

These areas include many of the

major urban centers in the eastern half

of the Nation. The combined population

for these areas is approximately 61.5

million. As described elsewhere, the

reductions called for in today’s action

will reduce ozone levels throughout

these areas.

Many more areas currently violate the

8-hour NAAQS. The EPA estimates that

a total population of approximately 73

million in the 23 jurisdictions live in

counties for which air quality is

monitored to be in violation of that

NAAQS. The reductions called for in

today’s action will reduce ozone levels

throughout these areas as well.

Moreover, as discussed below, many

of these areas are expected to be

classified as ‘‘transitional,’’ which

means, in most cases, that they are

expected to come into attainment solely

as a result of the reductions required by

today’s action. Thus, for those who live

in these areas, the reductions required

under today’s action, in-and-ofthemselves, are expected to mean the

difference between unhealthful ozone

levels and acceptable ozone levels.

Please note that EPA will not

designate ozone nonattainment areas for

the 8-hour NAAQS until 2000, and

these designations will be based on the

data that are most recently available at

that time.

C. Statutory and Regulatory Background

1. CAA Provisions

a. 1970 and 1977 CAA Amendments.

For almost 30 years, Congress has

focused major efforts on curbing

ground-level ozone. In 1970, Congress

amended the CAA to require, in title I,

that EPA issue, and periodically review
57360 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

1For moderate ozone nonattainment areas, the

attainment demonstration was due November 15,

1993 (section 182(b)(1)(A)), except that if the State

elected to conduct an urban airshed model, EPA

allowed an extension to November 15, 1994.

2 In addition, section 115 authorizes EPA to

require a SIP revision when one or more sources

within a State ‘‘cause or contribute to air pollution

which may reasonably be anticipated to endanger

public health or welfare in a foreign country.’’

and if necessary revise, NAAQS for

ubiquitous air pollutants (sections 108

and 109). Congress required the States

to submit SIPs to attain and maintain

those NAAQS, and Congress included,

in section 110, a list of minimum

requirements that SIPs must meet.

Congress anticipated that areas would

attain the NAAQS by 1975.

In 1977, Congress amended the CAA

by providing, among other things,

additional time for areas that were not

attaining the ozone NAAQS to do so, as

well as by imposing specific SIP

requirements for those nonattainment

areas. These provisions first required

the designation of areas as attainment,

nonattainment, or unclassifiable, under

section 107; and then required that SIPs

for ozone nonattainment areas include

the additional provisions set out in part

D of title I, as well as demonstrations of

attainment of the ozone NAAQS by

either 1982 or 1987 (section 172).

In addition, the 1977 Amendments

included two provisions focused on

interstate transport of air pollutants: the

predecessor to current section

110(a)(2)(D), which requires SIPs for all

areas to constrain emissions with

certain adverse downwind effects; and

section 126, which, in general,

authorizes a downwind State to petition

EPA to impose limits directly on

upwind sources found to adversely

affect that State. Section 110(a)(2)(D),

which is key to the present action, is

described in more detail below.

b. 1990 CAA Amendments. In 1990,

Congress amended the CAA to better

address, among other things, continued

nonattainment of the 1-hour ozone

NAAQS; the requirements that would

apply if EPA revised the 1-hour

standard; and transport of air pollutants

across State boundaries (Pub. L. 101–

549, Nov. 15, 1990, 104 Stat. 2399, 42

U.S.C., 7401–7671q). Numerous

provisions added, or revised, by the

1990 Amendments are relevant to

today’s proposal.

(1) 1-Hour Ozone NAAQS. In the 1990

Amendments, Congress required the

States and EPA to review and, if

necessary, revise the designation of

areas as attainment, nonattainment, and

unclassifiable under the ozone NAAQS

in effect at that time, which was the 1-

hour standard (section 107(d)(4)). Areas

designated as nonattainment were

divided into, primarily, five

classifications based on air quality

design values (section 181(a)(1)). Each

classification carries specific

requirements, including new attainment

dates (sections 181–182). In increasing

severity of the air quality problem, these

classifications are marginal, moderate,

serious, severe and extreme. The OTAG

region includes nonattainment areas of

all classifications except extreme.

As amended in 1990, the CAA

requires States containing ozone

nonattainment areas classified as

moderate or above to submit several SIP

revisions at various times. One set of

SIP revisions included specified control

measures, such as reasonably available

control technology (RACT) for existing

VOC and NOX sources (section

182(b)(2), 182(f)). In addition, the CAA

requires the reduction of VOC in the

amount of 15 percent by 1996 from a

1990 baseline (section 182(b)(1)).

Further, for nonattainment areas

classified as serious and above, the CAA

requires the reduction of VOC or NOX

emissions in the amount of 9 percent

over each 3-year period from 1996

through the attainment date (the rate-ofprogress (ROP) SIP submittals), under

section 182(c)(2)(B). In addition, the

CAA requires a demonstration of

attainment, including air quality

modeling, for the nonattainment area

(the attainment demonstration), as well

as SIP measures containing any

additional reductions that may be

necessary to attain by the applicable

attainment date (section 182(c)-(e)). The

CAA established November 15, 1994 as

the required date for the ROP and

attainment demonstration SIP

submittals for areas classified as serious

and above.1

(2) Revised NAAQS. Section 109(d) of

the CAA requires periodic review and,

if appropriate, revision of the NAAQS.

As amended in 1990, the CAA further

requires EPA to designate areas as

attainment, nonattainment, and

unclassifiable under a revised NAAQS

(section 107(d)(1); section 6103, Pub. L.

105–178). The CAA authorizes EPA to

classify areas that are designated

nonattainment under the new NAAQS

and to establish for those areas

attainment dates that are as

expeditiously as practicable, but not to

exceed 10 years from the date of

designation (section 172(a)).

(3) General Requirements. The CAA

continues, in revised form, certain

requirements, dating from the 1970

Amendments, which pertain to all areas,

regardless of their designation. All areas

are required to submit SIPs within

certain timeframes (section 110(a)(1)),

and those SIPs must include specified

provisions, under section 110(a)(2). In

addition, SIPs for nonattainment areas

are generally required to include

additional specified control

requirements, as well as controls

providing for attainment of any revised

NAAQS and periodic reductions

providing ‘‘reasonable further progress’’

in the interim (section 172(c)).

(4) Provisions Concerning Transport

of Ozone and Its Precursors. The 1990

Amendments reflect general awareness

by Congress that ozone is a regional, and

not merely a local, problem. As

described above, ozone and its

precursors may be transported long

distances across State lines to combine

with ozone and precursors downwind,

thereby exacerbating the ozone

problems downwind. The phenomenon

of ozone transport was not generally

recognized until relatively recently. Yet,

ozone transport is a major reason for the

persistence of the ozone problem,

notwithstanding the imposition of

numerous controls, both Federal and

State, across the country.

Section 110(a)(2)(D) provides one of

the most important tools for addressing

the problem of transport. This

provision, which applies by its terms to

all SIPs for each pollutant covered by a

NAAQS, and for all areas regardless of

their attainment designation, provides

that a SIP must contain adequate

provisions prohibiting its sources from

emitting air pollutants in amounts that

will contribute significantly to

nonattainment, or interfere with

maintenance, in one or more downwind

States.

Section 110(k)(5) authorizes EPA to

find that a SIP is substantially

inadequate to meet any CAA

requirement. If EPA makes such a

finding, it must require the State to

submit, within a specified period, a SIP

revision to correct the inadequacy.

The CAA further addresses interstate

transport of pollution in section 126,

which Congress revised slightly in 1990.

Subsection (b) of that provision

authorizes each State (or political

subdivision) to petition EPA for a

finding designed to protect that entity

from upwind sources of air pollutants.2

In addition, the 1990 Amendments

added section 184, which delineates a

multistate ozone transport region (OTR)

in the Northeast, requires specific

additional controls for all areas (not

only nonattainment areas) in that

region, and establishes the Ozone

Transport Commission (OTC) for the

purpose of recommending to EPA

regionwide controls affecting all areas in

that region. At the same time, Congress

added section 176A, which authorizes
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57361

3 Guidance for Implementing the 1-hour Ozone

and Pre-Existing PM10 NAAQS, Memorandum from

Richard D. Wilson, dated December 29, 1997.

the formation of transport regions for

other pollutants and in other parts of the

country.

2. Regulatory Structure

a. March 2, 1995 Policy.

Notwithstanding significant efforts, the

States generally were not able to meet

the November 15, 1994 statutory

deadline for the attainment

demonstration and ROP SIP

submissions required under section

182(c). The major reason for this failure

was that at that time, States with

downwind nonattainment areas were

not able to address transport from

upwind areas. As a result, in a

memorandum from Mary D. Nichols,

Assistant Administrator for Air and

Radiation, dated March 2, 1995, entitled

‘‘Ozone Attainment Demonstrations,’’

(March 2, 1995 Memorandum or the

Memorandum), EPA recognized the

efforts made by States and the

remaining difficulties in making the

ROP and attainment demonstration

submittals. The EPA recognized that

development of the necessary technical

information, as well as the control

measures necessary to achieve the large

level of reductions likely to be required,

had been particularly difficult for the

States affected by ozone transport.

Accordingly, as an administrative

remedial matter, the Memorandum

indicated that EPA would establish new

timeframes for SIP submittals. The

Memorandum indicated that EPA would

divide the required SIP submittals into

two phases. Phase I generally consisted

of (i) SIP measures providing for ROP

reductions due by the end of 1999, (ii)

an enforceable SIP commitment to

submit any remaining required ROP

reductions on a specified schedule after

1996, and (iii) an enforceable SIP

commitment to submit the additional

SIP measures needed for attainment.

Phase II consists of the remaining

submittals, beginning in 1997.

The Phase II submittals primarily

consisted of the remaining ROP SIP

measures, the attainment demonstration

and additional rules needed to attain,

and any regional controls needed for

attainment by all areas in the region.

The March 2, 1995 Memorandum

indicated that the attainment

demonstration, target calculations for

the post-1999 ROP milestones, and

identification of rules needed to attain

and for post-1999 ROP were due in mid1997. To allow time for States to

incorporate the results of the OTAG

modeling into their local plans, EPA

extended the mid-1997 submittal date to

April 1998.3

b. OTAG. In addition, the March 2,

1995 Memorandum called for an

assessment of the ozone transport

phenomenon. The Environmental

Council of the States (ECOS) had

recommended formation of a national

work group to allow for a thoughtful

assessment and development of

consensus solutions to the problem. The

OTAG was a partnership between EPA,

the 37 easternmost States and the

District of Columbia, industry

representatives, and environmental

groups. The OTAG’s air quality

modeling and recommendations formed

the basis for today’s action.

c. EPA’s Transport SIP Call

Regulatory Efforts. Shortly after OTAG

began its work, EPA began to indicate

that it intended to issue a SIP call to

require States to implement the

reductions necessary to address the

ozone transport problem. On January 10,

1997 (62 FR 1420), EPA published a

notice of intent that articulated this goal

and indicated that before taking final

action, EPA would carefully consider

the technical work and any

recommendations of OTAG. The EPA

published the NPR for the NOX SIP call

by notice dated November 7, 1997 (62

FR 60319). The NPR proposed to make

a finding of significant contribution due

to transported NOX emissions to

nonattainment or maintenance problems

downwind and to assign NOX emissions

budgets for 23 jurisdictions. The EPA

published a supplemental notice of

proposed rulemaking (SNPR) by notice

dated May 11, 1998 (63 FR 25902)

which proposed a model NOX budget

trading program and State reporting

requirements and provided the air

quality analyses of the proposed

statewide NOX emissions budgets. The

EPA received approximately 700

comments on these proposals. The

comment periods are described in

Section I.F, Discussion of Comment

Period and Availability of Key

Information. Throughout the course of

the rulemaking, EPA has added

information to the docket. By notice

dated August 24, 1998 (63 FR 45032),

EPA published a notice of availability

listing the additional documents placed

in the docket.

d. Revision of the Ozone NAAQS. On

July 18, 1997 (62 FR 38856), EPA issued

its final action to revise the NAAQS for

ozone. The EPA’s decision to revise the

standard was based on the Agency’s

review of the available scientific

evidence linking exposures to ambient

ozone to adverse health and welfare

effects at levels allowed by the preexisting 1-hour ozone standards. The 1-

hour primary standard was replaced by

an 8-hour standard at a level of 0.08

parts per million (ppm), with a form

based on the 3-year average of the

annual fourth-highest daily maximum 8-

hour average ozone concentration

measured at each monitor within an

area. The new primary standard will

provide increased protection to the

public, especially children and other atrisk populations, against a wide range of

ozone-induced health effects. Health

effects are described in paragraph I.B,

General Factual Background. The EPA

retained the applicability of the 1-hour

NAAQS for existing nonattainment

areas until such time as EPA determines

that an area has attained the 1-hour

NAAQS (40 CFR 50.9(b)).

The pre-existing 1-hour secondary

ozone standard was replaced by an 8-

hour standard identical to the new

primary standard. The new secondary

standard will provide increased

protection to the public welfare against

ozone-induced effects on vegetation.

D. Section 126 Petitions

In a separate rulemaking, EPA is

proposing action on petitions submitted

by eight northeastern States under

section 126 of the CAA. Each petition

specifically requests that EPA make a

finding that NOX emissions from certain

major stationary sources significantly

contribute to ozone nonattainment

problems in the petitioning State. The

eight States are Connecticut,

Massachusetts, Maine, New Hampshire,

New York, Pennsylvania, Rhode Island,

and Vermont.

Both the NOX SIP call and the section

126 petitions are designed to address

ozone transport through reductions in

upwind NOX emissions. However, the

EPA’s response to the section 126

petitions differs from EPA’s action in

the NOX SIP call rulemaking in several

ways. In today’s NOX SIP call, EPA is

determining that certain States are or

will be significantly contributing to

nonattainment or maintenance problems

in downwind States. The EPA is

requiring the upwind States to submit

SIP provisions to reduce the amounts of

each State’s NOX emissions that

significantly contribute to downwind air

quality problems. The States will have

the discretion to select the mix of

control measures to achieve the

necessary reductions. By contrast, under

section 126, if findings of significant

contribution are made for any sources

identified in the petitions, EPA would

determine the necessary emissions
57362 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

4The eight northeastern States that filed section

126 petitions also filed suit in the District Court for

the Southern District of New York, to compel EPA

to take action on those petitions within prescribed

periods. State of Connecticut v. Browner, No. 98–

1376 (S.D.N.Y., filed Feb. 25, 1998). The EPA and

the eight northeastern States jointly filed a motion

to enter a consent order prescribing certain dates for

EPA action.

limits to address the amount of

significant contribution and would

directly regulate the sources. A section

126 remedy would apply only to

sources in States named in the petitions.

Based on the view that the SIP call

and section 126 petitions are both

designed to achieve the same goal,

several commenters urged EPA to

coordinate the two actions to the

maximum extent possible. The EPA

agrees that the two actions are closely

related and, therefore, should be

coordinated. This will help provide

certainty for State and business

planning requirements. In addition, this

coordination can help to facilitate a

trading program among sources in SIP

call States that choose to participate in

the NOX trading program, and any

section 126 sources that would be

subject to a Federal NOX trading

program.

The section 126 provisions require

that any control remedy be

implemented within 3 years from the

date of the finding that major sources or

a group of stationary sources emit or

would emit in violation of the relevant

prohibition in section 110(a)(2)(D).

Under EPA’s anticipated rulemaking

schedule 4 on the petitions, the

compliance date for sources for which

EPA makes such a finding could be

April 30, 2002; November 30, 2002; or

May 1, 2003. Several commenters

expressed concern that the compliance

deadline under section 126 was driving

EPA’s decision on the compliance

deadline for the NOX SIP call.

Therefore, they believed that no changes

would be made in the proposed NOX

SIP call deadline in response to

comments.

While EPA believes it is advantageous

to coordinate the section 126 and NOX

SIP call actions, EPA disagrees that this

constrains EPA from being responsive to

public comments and considering

alternative compliance dates. See

discussion below in Section V, NOX

Control Implementation and Budget

Attainment Dates.

In the NOX SIP call NPR, EPA

proposed that States be required to

submit SIPs within 12 months of the

final SIP call. One commenter asserted

that the timing and terms of the

rulemaking schedule for the section 126

petitions precludes EPA from

considering public comments

advocating different SIP due dates for

the NOX SIP call. The section 126

rulemaking schedule provides several

options. One option would allow

findings on the petitions to be deferred

pending certain actions by the States

and EPA on State submittals in response

to the NOX SIP call. The premise for the

specified schedule is that the SIP due

date would be September 30, 1999 (i.e.,

roughly 12 months from signature of the

notice on the final NOX SIP call). As

discussed below in Section VI, SIP

Revision Criteria and Schedule, EPA

continues to believe 12 months is an

appropriate timeframe. However, had

EPA determined that a longer timeframe

for SIP submittal was warranted, the

section 126 rulemaking schedule would

not have restricted EPA from

establishing a later due date.

One commenter supported the section

126 rulemaking schedule because they

thought it had the effect of using the SIP

process rather than the source-based

petitions in that it provides an option of

deferring section 126 findings if EPA

approves a State’s NOX SIP. Another

commenter thought that the conditions

for deferring section 126 findings were

too stringent, and, therefore, section 126

would inevitably be triggered prior to

approval of any SIP provisions. This

issue is discussed in detail in Section

II.A.2.c. in the NPR EPA just issued on

the section 126 petitions, which appears

in the docket.

E. OTAG

As discussed in the proposed SIP call,

OTAG completed the most

comprehensive analyses of ozone

transport ever conducted. The EPA

participated extensively in this process.

The EPA believes that the OTAG

process was successful and generated

much useful technical and modeling

information on regional ozone transport.

This information provided EPA with the

foundation for this rulemaking.

The EPA received numerous

comments regarding the relationship

between the OTAG recommendations

and EPA’s proposed SIP call. Some

commenters asserted that the Agency’s

proposal was inconsistent with the

OTAG recommendations, while others

believed that EPA used the information

and recommendations from OTAG

appropriately. Primarily, commenters

stated that OTAG recommended a range

of controls for utility sources instead of

a uniform level of control for all of the

included States.

The OTAG did recommend

consideration of a range of controls, and

although it did not specifically

recommend uniform controls across a

broad region, such a control scheme is

within the range of its recommendation.

The EPA’s action today is based on its

consideration of OTAG’s

recommendations, as well as

information resulting from EPA’s

additional work, and extensive public

input generated through notice-andcomment rulemaking. The EPA

continues to believe, for reasons

explained in Section III.F.1, Uniform vs.

Regional Controls, that requiring NOX

emissions reductions across the region

in amounts achievable by uniform

controls is a reasonable, cost-effective

step to take at this time to mitigate

ozone nonattainment in downwind

States for both the 1-hour and 8-hour

standards.

Commenters also stated that EPA

applied an electric utility control level

that was more stringent than the upper

limit of the OTAG range of utility

controls. The OTAG recommended a

range of utility controls that falls

between specific CAA-required controls

and the less stringent of 85 percent

reduction from the 1990 rate (lb/

mmBtu), or 0.15 lb/mmBtu. In

determining the appropriate level of

emissions reductions, EPA considered

what levels of NOX reductions could be

obtained by applying, to various source

sectors, controls that are among the

most cost effective and feasible with

today’s proven pollution control

technologies. The EPA chose emissions

reductions that are equivalent to an

emission limit from utilities of 0.15 lb/

mmBtu. The EPA acknowledges that

this level may be more protective than

the most protective level contained in

the OTAG recommendation in some

cases, but, as discussed below in

Section IV, Air Quality Assessment,

EPA believes that it provides the most

improvement in air quality while

staying within the bounds of the most

highly cost-effective technology

available. (Cost effectiveness is

discussed in Section II.D.) In addition,

by relying on actual 1995–1996

continuous emission monitoring data,

rather than relying on estimated 1990

emission data, this approach provides a

more accurate way of determining the

States’ budgets since it minimizes any

chances of over-or under-estimation of

emissions.

Commenters asserted that OTAG

recommended 12 months for additional

modeling—especially subregional

modeling—before promulgating the SIP

call; and these commenters expressed

concern that EPA did not provide this

amount of time following publication of

the NPR. As discussed in more detail in

Section I.F, Discussion of Comment

Period and Availability of Key
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57363

5Ozone Transport Assessment Group Policy

Paper approved by the Policy Group on December

4, 1995.

6The OTAG recommendations are located in

Appendix B of the November 7, 1997 NPR (62 FR

60376).

7Letter to the Honorable Ken Calvert, Chairman,

Subcommittee on Energy and Environment, U.S.

House of Representatives, from Robert D. Brenner,

Acting Deputy Assistant Administrator for Air and

Radiation, U.S. EPA, June 26, 1998, transmitting

EPA’s responses to questions following the May 20,

1998 congressional hearing on EPA’s proposed rule

on paints and coatings.

Information, the Agency ultimately

provided approximately 1 year from the

conclusion of OTAG for States and other

members of the public to complete and

submit subregional and other types of

modeling. The EPA has considered this

additional modeling in finalizing

today’s rule.

Some commenters stated that the goal

of OTAG was to address attainment of

the ozone NAAQS. This is incorrect.

The OTAG’s goal was to reduce ozone

transport, which is one of the steps

necessary to enable attainment; the goal

was not to recommend an overall

strategy that would yield attainment

through regional measures alone. The

OTAG articulated its overall goal as

follows:

* * * identify and recommend a strategy

to reduce transported ozone and its

precursors which, in combination with other

measures, will enable attainment and

maintenance of the national ambient ozone

standard in the OTAG region. A number of

criteria will be used to select the strategy

including, but not limited to, cost

effectiveness, feasibility, and impacts on

ozone levels.5

It is also EPA’s goal to ensure that

sufficient regional reductions are

achieved to mitigate ozone transport in

the eastern half of the United States and

thus, in conjunction with local controls,

enable nonattainment areas to attain and

maintain the ozone NAAQS.

Commenters indicated that OTAG

focused only on the 1-hour standard

nonattainment problem and did not

assess compliance implications of the 8-

hour standard. For this reason,

according to commenters, EPA should

not base today’s action on the

nonattainment of the 8-hour NAAQS. It

is true that OTAG was established to

address transport issues associated with

meeting the 1-hour standard. The EPA

did not promulgate the 8-hour standard

until shortly after OTAG concluded;

thus, OTAG did not recommend

strategies to address the 8-hour NAAQS.

However, because EPA had proposed an

8-hour standard, OTAG did examine the

impacts of different strategies on 8-hour

average ozone predictions.

In light of OTAG’s work and

additional information, EPA is able to

assess ozone transport as it relates to the

8-hour NAAQS and to set forth

requirements as necessary to address the

8-hour standard in this rulemaking.

Ozone transport causes problems for

downwind areas under either the 1-hour

or 8-hour standard. The regional

reductions of NOX that will be achieved

through this SIP call for the 1-hour

NAAQS are key components for meeting

the new 8-hour ozone standard in a

cost-effective manner. Therefore, EPA

believes that the OTAG

recommendations for how to address

ozone transport are valid for both

NAAQS.

Several commenters urged EPA to

adopt and implement all Federal

measures identified in the OTAG

recommendations.6 The Agency is

committed to continue implementing

national control measures for NOX, as

recommended by OTAG. In addition,

EPA has adopted the following national

measures for purposes of reducing VOC:

architectural and industrial

maintenance coatings, consumer/

commercial products, and autobody

refinishing. The EPA has made no

decisions regarding further VOC

reductions beyond the reductions

specified as phase I in the OTAG

recommendations.7

Other more specific comments

concerning the OTAG recommendations

will be addressed throughout this

rulemaking as the issues are discussed.

F. Discussion of Comment Period and

Availability of Key Information

The EPA received numerous

comments concerning the adequacy of

the comment period for the November 7,

1997 NPR and May 11, 1998 SNPR.

Some commenters remarked that the

comment period for the NPR should be

extended to allow for development and

review of technical information,

including inventory data, growth

factors, and the resulting budget.

Commenters stated that the additional

time was particularly necessary for

subregional air quality modeling, which

is modeling designed to isolate the

impacts of emissions from a particular

State or group of States on downwind

areas. Many specifically requested an

additional 120 days, and one requested

an additional 9 months. Some

commenters indicated that EPA did not

incorporate their comments from the

NPR into the SNPR. Other commenters

insisted that key information supporting

the rule is not publicly available. The

EPA also received comments that

additional public hearings should be

held in other locations of the OTAG

region.

1. Request for Extension of the

Comment Period

The EPA allowed a 120-day public

comment period for the November 7,

1997 NPR, which closed on March 9,

1998. By notice (63 FR 17349, April 9,

1998), EPA reopened the comment

period for members of the public to

submit additional modeling analyses, as

well as comments concerning the

implications that any additional

modeling may have for the State NOx

budgets under consideration in the

November 7, 1997 proposal. The

comment period was reopened through

the end of the comment period on the

SNPR. The SNPR, which was published

on May 11, 1998, allowed a comment

period until June 25, 1998. Thus, for

most issues addressed in the NPR,

including air quality modeling issues,

commenters received an almost 8-month

formal comment period. Indeed, many

commenters had access to the NPR

immediately after October 10, 1997,

when it was signed and posted on an

EPA website. The Agency also received

a number of comments after June 25,

1998, which were also reviewed and

considered in developing the final rule.

The EPA believes this additional

opportunity for the public to submit

comments was reasonable. After March

9, 1998—the initial date for close of the

comment period on the NPR—EPA

received numerous comments on

various issues raised in the NPR,

including air quality issues. Many of

these comments were extensive, which

indicates that commenters received

adequate time.

With respect to the concern that EPA

did not incorporate comments received

on the NPR into the SNPR, it would not

have been practical for EPA to

incorporate comments received on the

NPR into the SNPR because the SNPR

was completed soon after the close of

the comment period for the NPR. In

general, the SNPR addressed different

aspects of the rule than the NPR, and

one of the purposes of the SNPR was to

take comment on several new issues, as

noted above. The EPA has addressed

comments on both the NPR and SNPR

in today’s action.

The major issues raised in the

comments are responded to throughout

the preamble of this final rule. A

comprehensive summary of all

significant comments, along with EPA’s

response to the comments which have

not been responded to in the preamble

(Response to Comments), can be found

in the docket for this rulemaking

(Docket No. A–96–56).
57364 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

8 Variable-Grid Urban Airshed Model.

9 In the NPR (62 FR 60318, 60363), EPA provided

estimates of the number of counties expected to

attain as a result of the NOX SIP call. The EPA will

update this list in the coming months. The updated

estimates of which counties will attain will be

based on more current air quality data and on the

State-by-State emissions budgets contained in

today’s final rule.

10The ‘‘transitional classification’’ EPA intends

for 8-hour ozone nonattainment areas is further

discussed in the NPR (62 FR 60318, 60363).

2. Request for Time to Conduct

Additional Modeling

The OTAG Policy Group, at its June

3, 1997 meeting, recommended that

States have the opportunity to conduct

additional local and subregional

modeling and air quality analyses, as

well as to develop and propose

appropriate levels and timing of

controls. The EPA received numerous

comments related to OTAG’s

recommendation. The commenters

requested that the Agency give States

more time to conduct this additional

modeling so that EPA could more

accurately assess each State’s

contribution to downwind

nonattainment.

The EPA signed the NPR on October

10, 1997, and posted it on a website at

that time, although it was not published

in the Federal Register until November

7, 1997. As noted above, EPA reopened

the comment period through June 25,

1998 for submittal of additional air

quality modeling runs. In effect, this has

extended the amount of time for

modeling analyses to over a year from

the date OTAG submitted its

recommendations, and to over 8 months

from the signature date for the NPR. By

the close of the comment period on June

25, 1998, EPA had received numerous

comments containing new and

extensive air quality modeling studies.

Accordingly, EPA believes that

commenters received adequate time.

3. Availability of Key Information

A number of commenters asserted

that EPA failed to make publicly

available key information, such as

modeling and emissions inventory data.

Specifically, commenters stated that

they did not have access to the

emissions data on which EPA based the

air quality modeling for the NPR. In

addition, according to some

commenters, several models used by

EPA and OTAG are proprietary models

and have not been generally available to

the public.

In Section III.A.2, Availability, the

Agency discusses the availability of

emissions inventory data to the public.

The OTAG and EPA conducted air

quality modeling runs to determine the

level of contribution from emissions in

upwind areas to ozone nonattainment in

downwind areas. Some of this modeling

employed UAM–V.8 The UAM–V has

generally been available to the public

for the purpose of analyzing information

relevant to today’s rulemaking. State

and local agencies, as well as utility

companies and other stakeholders, have

had access to licenses to use UAM–V.

Commenters objected that they were

obliged either to purchase licenses for

use of the UAM–V model or to employ

as a contractor the model owner, and

that these financial constraints

restricted their access to the model.

Because this model has, in general, been

privately developed, EPA believes that

reasonable fees for its use should be

expected. The EPA did not receive

information indicating that the

associated expenses were other than

reasonable. To the extent that

commenters experienced delays in

obtaining the UAM–V model, EPA

believes that the extensions of the

comment period resulted in adequate

time for comment. In any event, any

commenter who was not able to gain

access in the timeframe desired was able

to use a comparable model, such as the

Comprehensive Air Quality Model with

Extensions (CAMx), which is not

proprietary. For the purpose of

responding to public comments, EPA is

considering all information based on

CAMx and similar models.

The Agency made available additional

modeling runs used to determine

emissions changes, costs and cost

effectiveness for electricity generating

units (EGUs). These runs were placed

on the IPM Analyses web site at

www.epa.gov/capi, with links to EPA’s

Office of Air and Radiation Policy and

Guidance web site.

On August 10, the EPA placed in the

docket and made available on the web

site, modeling analyses and other

information supporting today’s action.

As noted above, by notice dated August

24, 1998 (63 FR 45032), EPA published

a notice of availability which stated that

throughout the course of the

rulemaking, EPA had placed

information in the docket or made it

available on various web sites. This

information included inventory data

and additional modeling runs. By

placing those materials in the docket

and informing the public of their

availability, EPA provided 4–6 weeks

for review and comment by the public.

The EPA did receive comments

concerning this information from the

Utility Air Regulatory Group on

September 9, and EPA is responding to

those comments in the Response To

Comments document. The EPA notes

that the additional modeling analyses

were performed in response to

comments received on the NPR urging

EPA to conduct State-by-State modeling.

The Agency does not believe it is

required to provide for additional

comment on every action it takes in

response to comment, particularly

where, as here, the new information

confirms the Agency’s proposed

conclusions. Therefore, the Agency did

not further extend the comment period.

4. Public Hearings

The Agency conducted two hearings

in Washington, DC, including a 2-day

hearing on February 3–4, 1998 for the

NPR, and a 1-day hearing on May 29,

1998 for the SNPR. Some commenters

believe that additional public hearings

should have been held in other

locations in the OTAG region. The EPA

believes these hearings provided

reasonable opportunity for oral

comment on the proposed rulemaking

given the timeframes associated with

this rulemaking. Therefore, the Agency

did not schedule any additional

hearings. The public also had an

opportunity to submit written testimony

within approximately 30 days after each

hearing date.

G. Implementation of Revised Air

Quality Standards

On July 18, 1997, EPA published its

final rule for strengthening the NAAQS

for ozone by establishing an 8-hour

standard (62 FR 38856). Current

monitoring data indicate that many

areas in the East, Midwest and South

violate the 8-hour NAAQS. Along with

areas violating the 1-hour NAAQS, areas

violating the 8-hour NAAQS are also

affected by the transport of ozone across

the East. The regional NOX reduction

strategy finalized in today’s action will

provide a mechanism to achieve

reductions that will assist States in

attaining and maintaining this revised

standard. In fact, the regional reductions

alone should be enough to enable the

vast majority of the new counties

violating the 8-hour NAAQS that are

located in States throughout the East to

attain the revised 8-hour standard.9

On July 16, 1997, President Clinton

issued a directive on the

implementation of the revised air

quality standards. This implementation

policy was described in the NPR (62 FR

60318, 60362–64). The EPA received

numerous comments on this

implementation policy and on EPA’s

plan to create a transitional

classification10 for 8-hour ozone

nonattainment areas that meet certain
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57365

11For a complete listing of the guidance and other

actions EPA plans to issue to implement the revised

ozone and PM NAAQS, see a table on EPA’s

implementation website: http://

ttnwww.rtpnc.epa.gov/implement/actions.htm.

criteria. Since these comments concern

implementation efforts for the revised 8-

hour ozone standard and do not relate

directly to the NOX SIP call on which

EPA is taking final action in this

rulemaking, EPA is not responding in

detail to the comments. The EPA will

address implementation of the revised

standard separately. In August 1998,

EPA issued proposed guidance for

public comment to explain the

implementation policy in further detail

and to provide details on SIP

requirements for transitional areas (63

FR 45060, August 24, 1998). The EPA

expects to finalize the August 1998 draft

guidance, as well as guidance for areas

other than transitional, by December

1998.11

H. Summary of Major Changes Between

Proposals and Final Rule

This summary describes the major

changes that have occurred since the

NPR and SNPR in each of the following

sections of today’s final rule.

1. EPA’s Analytical Approach (Section

II.A)

• The NPR proposed two

interpretations for the section

110(a)(2)(D)(i)(I) provisions concerning

the ‘‘significant contribution’’ test.

Under the first, EPA would examine

certain factors relating to level of

emissions and their ambient impact to

determine whether to make a finding

that all of the emissions from a

particular State’s sources contribute

significantly to nonattainment or

maintenance problems downwind. If

EPA made such a finding, then EPA

would examine certain cost factors to

determine the extent to which the SIP

for the State must mitigate (reduce) its

emissions. Under the second

interpretation, EPA would examine all

of those factors together—level of

emissions, ambient impact, and costs—

to determine whether to make the

finding with respect to a specified

amount of emissions. If EPA made the

finding, then it would require the SIP to

eliminate that amount. In today’s final

rule, EPA is adopting the second

interpretation. The EPA indicates,

however, that it would adopt the same

rule if it were instead implementing the

first interpretation.

2. Cost Effectiveness of Emissions

Reductions (Section II.D.)

• The methodology of determining

cost effectiveness has not changed. For

all sources, the inventory and as a

result, the source-specific costs, in some

cases, have changed. This results in a

different overall budget level and a

different overall cost-effectiveness

value. For the non-EGUs, while the

methodology has not changed, the

analysis focuses on large non-EGU

sources. The methodology in the NPR

focused on all non-EGU sources.

3. Determination of Budgets (Section

III.)

• For EGU, the EPA maintained the

approach to use the higher, by State, of

1995 or 1996 heat input data to

calculate baseline heat input rates for

the NFR, and added 577 smaller units

to the State budget inventories which

had erroneously been omitted from the

NPR. These units included electricity

generating sources of 25 megawatts

(MW) or less of electrical output and

additional units not affected under the

Acid Rain Program. Additional controls

are not assumed for these sources, but

they are added to the budget at baseline

levels. The Agency has decided to use

State-specific growth factors derived

from application of the IPM using the

1998 Base Case and chose to retain the

0.15 lbs/mmBtu as the assumed uniform

control level for EGU budget emissions

determination.

• The EPA examined alternatives that

focus on non-EGU point source

reductions from the largest source

categories, and within each of these

categories assumed controls that would

result in a regionwide average cost

effectiveness less than $2000/ton. The

resulting budget assumes the emissions

reductions from large non-EGU sources

that are among the most cost effective to

control and does not include reductions

from smaller sources and sources that,

as a group, are not quite as cost effective

or efficient to control, or are already

covered by other Federal measures. As

a result, this final rule assumes, for

purposes of calculating the State NOX

budgets, the following emissions

decreases from uncontrolled levels for

the large (generally greater than 250

mmBtu or 1 ton/day non-EGU sources

(no emission reductions are assumed for

the smaller sources):

—Non-EGU boilers and turbines—60

percent decrease.

—Stationary internal combustion

engines—90 percent decrease.

—Cement manufacturing plants—30

percent decrease.

It should be noted that point sources

with capacities less than 250 mmBtu/hr

but with emissions greater than 1 ton/

day are not treated differently from

sources with capacities greater than 250

mmBtu/hr for purposes of calculating

the budget. This is a change from the

NPR which included RACT controls on

units with capacities less than 250

mmBtu/hr and emissions greater than 1

ton/day (see Section III.G.2.a). As under

the proposal, the rule allows States to

choose control measures other than the

EPA-assumed controls to meet the

numerical budgets.

• The EPA has implemented the

following changes that the Agency

proposed in the NPR for calculating

baseline NOX emissions from highway

vehicles. A 1995 baseline is used for the

final rule in place of the 1990 baseline

used in the NPR. The Highway

Performance and Monitoring System

data were used to estimate States’ 1995

vehicle miles traveled (VMT) by vehicle

category, except in those cases where

EPA accepted revisions offered in the

comments. Today’s action includes

those mobile source reductions which

EPA has determined are appropriate to

implement on a national basis, and

which have been promulgated in final

form or are expected to be promulgated

in final form before States are required

to comply with their budgets. The

highway vehicle budget components

include the emission reductions

resulting from implementation of the

National Low Emitting Vehicle (NLEV)

program, including the phase-in

schedule agreed to by the States,

automobile manufacturers, and EPA.

The highway budget components do not

include the effect of Tier 2 light-duty

vehicle and truck standards and any

associated fuel standards since these

standards have not yet been proposed.

The extent of the reformulated gasoline

(RFG) and inspection and maintenance

(I/M) programs was not assumed to

change beyond that assumed for the

NPR, except for those States that were

able to demonstrate that the NPR’s

modeling assumptions did not conform

to the State’s SIP and did not reflect

CAA requirements.

• The EPA has chosen to retain the

1990 baseline inventories for nonroad

mobile sources presented in the NPR for

today’s action, with additional changes

made in response to public comments.

The control strategies assumed for

calculating the nonroad and stationary

area source budget components have not

changed from the SNPR.

4. NOX Control Implementation and

Budget Achievement Dates (Section V)

• The EPA proposed that the SIP

revisions require full implementation of

the necessary State measures by

September 2002 and took comment on

a range of dates from September 2002

through September 2004. Based on
57366 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

public comments and feasibility

analyses conducted by EPA, the Agency

is requiring an implementation date of

May 1, 2003. The Agency is also

providing some compliance flexibility

to States for the 2003 and 2004 ozone

seasons by establishing State

compliance supplement pools. This is

described in Section III.F.6.

5. SIP Criteria (Section VI.A)

• The Agency has determined that the

additional SIP approvability criteria, as

proposed in the SNPR, should apply not

only when States choose to regulate

EGUs (63 FR 25912), but also when

States choose to regulate large steamproducing units (i.e., combustion

turbines and combined cycle systems

with a capacity greater than 250

mmBtu/hr).

• The Agency proposed revisions to

part 51 requiring continuous emissions

monitoring systems (CEMS) on all large

electrical generating and steamproducing sources which States elect to

subject to emissions reduction

requirements in response to this

rulemaking. The EPA took comment on

requiring that, if a State chooses to

regulate these sources to meet the SIP

call, the SIP must require these sources

to use the NOX mass monitoring

provisions of part 75, subpart H, to

demonstrate compliance with

applicable emissions control

requirements. After considering

comments, the Agency is requiring that,

in these circumstances, the SIP specify

that large sources comply with the

monitoring provisions of part 75,

subpart H, which includes non-CEMS

monitoring options for units that are

infrequently operated or units that have

low mass emissions.

6. Emissions Reporting Requirements

for States (Section VI.B)

• The proposed rule required that

States report full-year, as well as ozoneseason, emissions from all sources for

the triennial inventories commencing

with year 2002 emissions and the 2007

inventory, and for those sources for

which reports had to be submitted

annually starting with year 2003

emissions. The final rule requires only

ozone-season emissions reporting for all

sources.

• In the SNPR, the EPA proposed, for

purposes of reporting requirements, to

define a point source as a non-mobile

source which has NOX emissions of 100

tons/year or greater. Under today’s

action, States have the option of

establishing a smaller emission

threshold than 100 tons/year of NOX

emissions in defining point source. This

will allow the definition of point source

to remain consistent with current

definitions in local areas.

7. NOX Budget Trading Program

(Section VII.)

• For States that choose to participate

in the NOX Budget Trading Program, the

preamble clarifies the intent of the

model rule and identifies areas of the

rule where States have flexibility to

include variations in their State rules.

• In the SNPR, the Agency solicited

comment on a range of options for

incorporating banking into the trading

program. After considering these

comments, the Agency is including

banking provisions in the final rule. The

provisions allow for unlimited banking

starting in 2003 and includes a flow

control mechanism to limit the

emissions variability associated with

banking.

• One of the banking approaches

presented in the SNPR included the

option for sources to generate and use

early reduction credits. Consistent with

the provisions of the NOX SIP call

which provide for State compliance

supplement pools, the final rule allows

States to issue early reduction credits

for certain NOX emissions reductions

achieved between September 30, 1999

and May 1, 2003.

• The final rule clarifies the timing

requirements for State submission of

allowance allocations to EPA and, as

proposed, lays out an allocation

approach. Each State remains free to

adopt the final rule’s allocation

approach or adopt an allocation scheme

of its own, provided it meets the

specified timing requirements, requires

new sources to hold allowances, and

does not allocate more allowances than

are available in the State trading budget.

8. Interaction with Title IV NOX Rule

(Section VIII.)

• In the SNPR, EPA proposed

revisions to part 76 addressing the

interaction between title IV and the NOX

SIP call. In this final rule, EPA explains

that the Agency is not adopting any of

the proposed revisions to part 76.

9. Administrative Requirements

(Section X.)

• NPR Section VIII, Regulatory

Analyses, has been replaced in the final

rule by Section X.A, Executive Order

12866: Regulatory Impacts Analysis.

The new final rule Section X.A

indicates that EPA has prepared a RIA

for the final rule and cites the cost and

benefit estimates from that analysis.

• The final rule adds several Sections

under X, Administrative Requirements,

that were absent from the NPR. These

include: Paperwork Reduction Act;

Executive Order 13045: Protection of

Children from Environmental Health

Risks and Safety Risks; Executive Order

12898: Environmental Justice; Executive

Order 12875: Enhancing the

Intergovernmental Partnerships;

Executive Order 13084: Consultation

and Coordination with Indian Tribal

Governments; Judicial Review; and

Congressional Review Act. These new

Sections provide a more comprehensive

summary of the Acts and Executive

Orders that could apply to the final rule.

Each Section identifies the requirements

of the relevant Act or Executive Order,

indicates EPA’s interpretation of

whether the Act or Executive Order

actually applies to this rulemaking, and,

if so, indicates how the Agency has

addressed the Act or Executive Order.

II. EPA’s Analytical Approach

A. Interpretation of the CAA’s Transport

Provisions

As indicated in the NPR, 62 FR 60323,

the primary statutory basis for today’s

action is the ‘‘good neighbor’’ provision

of section 110(a)(2)(D)(i)(I), under

which, in general, each SIP is required

to include provisions assuring that

sources within the State do not emit

pollutants in amounts that significantly

contribute to nonattainment or

maintenance problems downwind. This

statutory requirement applies to SIPs

under both the 1-hour ozone NAAQS

and the 8-hour ozone NAAQS.

1. Authority and Process for Requiring

SIP Submissions Under the 1-Hour

Ozone NAAQS

a. Authority for Requiring SIP

Submissions under the 1-Hour NAAQS.

Each State is currently required to have

in place a SIP that implements the 1-

hour ozone NAAQS for areas to which

that standard still applies. In the

NAAQS rulemaking, EPA determined

that the 1-hour NAAQS would cease to

apply to areas that EPA determines have

air quality in attainment of that NAAQS

(40 CFR 50.9(b)). In two recent

rulemakings, EPA identified numerous

areas of the country to which the 1-hour

NAAQS no longer applies. ‘‘Final Rule:

Identification of Ozone Areas Attaining

the 1-Hour Standard and to Which the

1-Hour Standard is No Longer

Applicable,’’ (63 FR 31014, June 5,

1998); ‘‘Final Rule: Identification of

Additional Ozone Areas Attaining the 1-

Hour Standard and to Which the 1-Hour

Standard is No Longer Applicable,’’ (63

FR 27247, July 22, 1998).

The 1-hour NAAQS remains

applicable to areas whose air quality

continues to monitor nonattainment. As

noted above in Section I.B, General
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57367

12As discussed in the NPR and in greater detail

further below, the basis for requiring a transportrelated SIP revision for the 8-hour standard is the

requirement in section 110(a)(1) that States submit

SIPs meeting the requirements of section 110(a)(2)

within 3 years (or an earlier date established by

EPA) of promulgation of a new or revised NAAQS.

This is discussed in further detail below.

13Taken to its logical conclusion, the

commenters’ argument would mean that States are

precluded from submitting a section 110(a)(2)(D)

SIP unless it reflects measures recommended

through the transport commission process. The EPA

does not believe that Congress would first establish

a specific mandate (to submit a SIP to address

interstate transport) and then limit it in such a

cryptic fashion. If Congress intended section

110(a)(2)(D) SIPs to only reflect transport

commission recommendations, Congress could

have specifically referenced sections 176A and 184

in section 110(a)(2)(D), rather than generally

providing that SIPs be ‘‘consistent’’ with title I of

the CAA.

Factual Background, these include

many major urban areas in the eastern

half of the United States. States that

contain these areas remain responsible

for meeting CAA requirements

applicable to those areas for the purpose

of attaining the 1-hour NAAQS. For

example, States are responsible for

attainment demonstrations for areas

designated nonattainment and classified

as moderate or higher.

By the same token, States that are

upwind of these areas are responsible to

meet the ‘‘good neighbor’’ requirements

of section 110(a)(2)(D). This

responsibility is not alleviated simply

because, for areas other than the current

nonattainment areas, the 8-hour NAAQS

has replaced the 1-hour NAAQS.

b. Process for Requiring SIP

Submissions under the 1-Hour NAAQS.

As explained in the NPR, the

appropriate route for EPA to require SIP

submissions under section

110(a)(2)(D)(i)(I) with respect to the 1-

hour standard is issuance of a ‘‘SIP call’’

under section 110(k)(5).12 Section

110(k)(5) authorizes EPA to find that a

SIP is substantially inadequate to meet

a CAA requirement and to require (‘‘call

for’’) the State to submit, within a

specified period, a SIP revision to

correct the inadequacy. Specifically,

section 110(k)(5) provides, in relevant

part:

Whenever the Administrator finds that the

applicable implementation plan for any area

is substantially inadequate to attain or

maintain the relevant [NAAQS], to mitigate

adequately the interstate pollutant transport

described in section 176A or section 184, or

to otherwise comply with any requirement of

this Act, the Administrator shall require the

State to revise the plan as necessary to

correct such inadequacies. The Administrator

shall notify the State of the inadequacies, and

may establish reasonable deadlines (not to

exceed 18 months after the date of such

notice) for the submission of such plan

revisions.

By today’s action, EPA is determining

that the SIPs for the specified

jurisdictions are substantially

inadequate to comply with the

requirements of section 110(a)(2)(D)(i)(I)

because the relevant SIPs do not contain

adequate provisions prohibiting their

sources from emitting amounts of NOX

emissions that contribute significantly

to nonattainment in downwind areas

that remain subject to the 1-hour

NAAQS. Based on these determinations,

EPA is requiring the identified States to

submit SIP revisions containing

adequate provisions to limit emissions

to the appropriate amount.

If a State does not submit the required

SIP provisions in response to this SIP

call, EPA will issue a finding that the

State failed to make a required SIP

submittal under section 179(a). This

finding has implications for sanctions as

well as for EPA’s promulgation of

Federal implementation plans (FIPs).

Sanctions and FIPs are discussed in

Section VI, SIP Criteria and Emissions

Reporting Requirements.

(1) Commenters’ Arguments

Concerning the Transport Provisions.

Commenters argued that EPA does not

have unilateral authority to issue a SIP

call under section 110(k)(5) to require

States to remedy SIPs that do not meet

the requirements of section 110(a)(2)(D).

The commenters noted that when

Congress amended the CAA in 1990,

Congress provided that the sole

authority for EPA and States to address

interstate transport of pollution is

through transport commissions. In

support, the commenters state that

Congress: (i) Added sections 176A and

184, which authorize the establishment

of transport regions and the formation of

transport commissions; (ii) revised

section 110(k)(5) to refer to those

transport provisions; and (iii) revised

section 110(a)(2)(D)(i) to require that SIP

provisions designed to eliminate

interstate pollutant transport be

consistent with other CAA

requirements. According to the

commenters, these provisions, read as a

whole, mandate that if EPA believes that

a transport problem exists, EPA’s sole

recourse is to form a transport region

under sections 176A and/or 184; EPA

may issue a SIP call to mandate

compliance with section 110(a)(2)(D)(i)

only in response to a recommendation

of the transport region. The commenters

also claim that this scheme is sensible

because it provides a consensual forum

for States to address interstate pollution

rather than allowing unilateral action on

the part of EPA or a State.

The EPA disagrees with the

commenters’ conclusion that these

statutory provisions make clear that

EPA cannot require a State to address

interstate transport without first

establishing a transport commission and

in the absence of a recommendation

from the transport commission. There is

no language of limitation in sections

110(a)(2)(D) or (k)(5), or 176A, or 184.

Nor is there any support in the

legislative history for such a narrow

reading of the statute. Moreover, under

the commenters’ interpretation, the

CAA Amendments of 1990 have placed

greater constraints on States’ and EPA’s

ability to address the interstate transport

of pollution. Such an interpretation

would be inconsistent with the overall

purpose of the CAA to ensure healthful

air. Thus, EPA believes that the

transport provisions were added as an

additional tool to address interstate

transport but were not intended to

preclude other methods of addressing

interstate pollution than prior to passage

of the amendments.

Under the 1990 Amendments,

Congress recognized the growing

evidence that ozone and its precursors

can be transported over long distances

and that the control of transported

ozone was a key to achieving attainment

of the ozone standard across the nation

(Cong. Rec. S16903 (daily ed. Oct. 27,

1990) (statement of Sen. Mitchell);

S16970 (conference report) S16986–87

(statement of Sen. Lieberman)). Thus, in

1990, Congress added a new mechanism

to address interstate transport.

Specifically, Congress enacted sections

176A and 184, which provide a

mechanism for States to work together

to address the interstate transport

problem. However, by their terms, these

sections simply provide authority for

EPA to designate transport regions and

establish transport commissions. There

is nothing in the language of these

provisions that indicates that they

supersede the other statutory

mechanisms for addressing interstate

transport, or that they now provide the

sole mechanism for resolving interstate

pollution transport.

Moreover, although Congress

expressly added these two provisions

through the 1990 Amendments,

Congress did not in any way limit

section 110(a)(2)(D), which requires

States to address interstate transport in

their SIPs. The addition of the language

providing that States’ actions under

section 110(a)(2)(D) be ‘‘consistent with

[title I] of the Act’’ cannot be read to

limit the controls States may adopt to

meet section 110(a)(2)(D) to those

recommended by a transport

commission.13 After all, the transport

region provisions are only two of many

provisions in title I. Rather, this
57368 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

14 In Commonwealth of Virginia v. EPA, 108 F.3d

1397 (D.C. Cir. 1997), the court vacated EPA’s SIP

call in response to the Northeast Ozone Transport

Commission’s recommendation on the basis that the

EPA could not require States to adopt a specific

control measure under its section 110(k)(5)

authority and that, in any event, EPA could not

require States to adopt stricter motor vehicle

emission standards under either section 110(k)(5) or

section 184.

language concerning consistency should

be read as clarifying that any section

110(a)(2)(D) requirement must be

consistent with other provisions of title

I. Similarly, this language makes

explicit that SIP revisions required in

accordance with the procedures of the

transport provisions would meet the

requirements of section 110(a)(2)(D)(i).

Furthermore, it is significant that

Congress did not in any sense bind

EPA’s ultimate discretion to determine

whether State plans appropriately

address interstate transport. Under

sections 176A and 184, the States may

only make recommendations to EPA.

Thus, under the transport provisions, as

well as the general SIP requirements of

section 110(a)(2), EPA must ultimately

decide whether the SIP meets the

applicable requirements of the CAA. If,

as the commenters contend, EPA is

limited to calling on States to address

interstate transport only by strategies

recommended by the State, then EPA

would be precluded from ensuring that

States address interstate transport. For

example, EPA could establish a

transport commission but the

commission could fail to make

recommendations or make insufficient

recommendations. (Section 176A

provides that transport commissions

may make recommendations to EPA

only by ‘‘majority vote of all members’’

other than those representing EPA.)

Such a reading of the statute would be

absurd in light of the growing

recognition at the time of the 1990

Amendments that transport is a real

threat to the primary purpose of title I

of the CAA—attainment of the NAAQS.

By the same token, in amending

section 110(k)(5) in the 1990

Amendments, Congress did not add

anything that explicitly provides that, in

the case of interstate transport, section

110(k)(5) would apply only when EPA

approved (or substituted measures for) a

transport commission’s

recommendations. The reference in

section 110(k)(5) to the transport

provisions of sections 176A and 184

does not preclude EPA’s use of the SIP

call provision to call on States to ensure

their SIPs meet the requirements of

section 110(a)(2)(D)(i). Section 110(k)(5)

also provides for EPA to call on States

‘‘to otherwise comply with requirements

of this Act;’’ among the requirements in

chapter I of the CAA is the requirement

in section 110(a)(2)(D). The reference in

section 110(k)(5) to the transport

provisions simply makes explicit that

EPA may employ section 110(k)(5) for

the additional purpose of requiring SIPs

to include the control measures as

recommended by transport commissions

and approved by EPA under the

transport provisions.

Moreover, there is no indication in

the legislative history of the 1990

Amendments that Congress intended

the sections 176A and 184 transport

provisions to supersede the section

110(k)(5) SIP call mechanism for

ensuring compliance with section

110(a)(2)(D)(i). Reading the transport

provisions to supersede the SIP call

mechanism would constitute a

significant change from the CAA as it

read prior to the 1990 Amendments.

Even if the statute is ambiguous as to

whether the transport provisions

supersede the SIP call mechanism—and

EPA believes the statute is clear that the

transport provisions do not supersede—

congressional silence would suggest that

Congress did not intend such a

significant change (See generally

Harrison v. PPG Industries, Inc., 446

U.S. 578, 602, 100 S.Ct. 1889, 1902, 64

L.Ed.2d 525 (1980) (Rehnquist, J.,

dissenting), cited with approval in

Chisom v. Roemer, 501 U.S. 380, 396 n.

23, 111 S.Ct. 2354, 2364 n. 23, 115

L.Ed.2d 348 (1991)).

Finally, the commenter asserts that

EPA’s interpretation of the CAA to

allow a SIP call in the absence of a

transport commission recommendation

reads out of the CAA the consensual

transport commission procedures under

sections 176A and 184. This is simply

not true. The EPA interprets the

transport commission process to be one

tool to assess and address interstate

transport. In fact, the Northeast Ozone

Transport Commission, under section

184, has been active since enactment of

the 1990 Amendments. In 1995, EPA

approved a recommendation of that

commission (60 FR 4712 14). Transport

commissions remain a viable means for

dealing with interstate transport.

Furthermore, contrary to the general

implication of the commenter’s remark,

the OTAG process, though not a formal

transport commission, provided an

opportunity not only for Federal and

State governments to assess jointly the

transport issue, but also involved

industry, environmental groups and

others. The EPA based its SIP call on

information developed through OTAG,

as well as additional analyses performed

by the Agency and information

submitted by a variety of groups during

the comment period on the proposed

rule. Thus, the OTAG process contained

consensual elements.

(2) Commenters’ Arguments

Concerning the Virginia case. Under one

of the approaches described in the

proposed rule, EPA proposed to

determine, for each of various upwind

States, the aggregate ‘‘amounts’’ of air

pollutants (NOX) that contribute

significantly to nonattainment, and that,

therefore must be prohibited by the

various SIPs. The NOX emissions budget

for each State is an expression of the

amount of NOX emissions that would

remain after the State prohibits the

amount that contributes significantly to

downwind nonattainment. In the final

rule issued today, EPA has continued

this approach, establishing emissions

budgets for each of the 23 jurisdictions

based on required reductions. This

determination is an important step

toward assuring that overall air quality

standards are met downwind.

Commenters argue that even if EPA

has authority to call on States to address

interstate transport, EPA does not have

the authority under section 110(a)(2)(D)

to mandate that upwind States limit

NOX emissions to specified amounts.

Rather, according to this view, EPA’s

authority is limited to determining that

the upwind States’ SIPs are inadequate,

and generally requiring the upwind

States to submit SIP revisions to correct

the inadequacies. The upwind States

would then, according to this view,

submit a SIP revision that implements

what the upwind States determine to be

the appropriate amount of NOX

reductions. If EPA believes that those

amounts are too small to correct the

inadequacy, EPA could disapprove the

SIP revisions.

Proponents of this view rely on the

recent decision in Virginia v. EPA, 108

F.3d 1397, 1406–10 (D.C. Cir. 1997)

(Virginia) (citing Train v. NRDC), in

which the court vacated EPA’s SIP call

on the basis that through it, EPA gave

States no choice but to adopt the

California low emission vehicle (LEV)

program. The court found that the

language in section 110(k)(5) that

provides EPA with the authority to call

on a State to revise its SIP ‘‘as

necessary’’ to correct a substantial

inadequacy did not change the

longstanding precept that States have

the primary authority for determining

the mix of control measures needed to

attain the NAAQS.

The EPA disagrees that the CAA

prohibits EPA from establishing an

emissions budget through a SIP call

requiring upwind States to prohibit

emissions that contribute significantly

to downwind nonattainment. Section
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57369

15The EPA is not contending that the ‘‘as

necessary’’ language in section 110(k)(5) provides

the basis for EPA’s authority to identify the

emissions budget for upwind States.

16The court’s decision in Train v. NRDC appears

to rely on the plain language of the statute in

holding that a State is primarily responsible for

determining the mix of control measures necessary

to demonstrate attainment within that State’s

borders. The court in Virginia appears to adopt this

‘‘plain meaning’’ interpretation without addressing

that the language in section 107(a) applies only to

intrastate issues. This issue is not relevant in the

present case, however, since States are free to

decide the mix of control measures under today’s

final action.

110(a)(2)(D) is silent regarding whether

States or EPA are to determine the level

of emission reductions necessary to

mitigate significant contribution. The

caselaw cited by the commenters only

provides that States are primarily

responsible for determining the mix of

control measures—not the aggregate

emission reduction levels that are

necessary. Moreover, Train v. NRDC,

which underlies the Virginia court’s

decision, relied on section 107(a) of the

CAA, which specifies only that each

State is primarily responsible for

determining a control strategy to attain

the NAAQS ‘‘within such State.’’

Section 110(a)(2)(D) does not provide

who—EPA or the States—is to

determine the level of emission

reductions necessary to address

interstate transport. As quoted above,

section 110(a)(2)(D)(i)(I) requires that

SIPs contain ‘‘adequate provisions

prohibiting * * * [sources] from

emitting any air pollutant in amounts

which will contribute significantly to

nonattainment’’ downwind. Nor does

this provision indicate the criteria for

determining the ‘‘amounts’’ of

pollutants that contribute significantly

to nonattainment downwind. Nor does

this provision indicate the process for

determining those ‘‘amounts,’’ including

whether EPA or the States should carry

out this responsibility. 15 Under Chevron

U.S.A., Inc. v. Natural Resources

Defense Council, 468 U.S. 1227, 105

S.Ct. 28, 82 L.Ed.2d 921 (1984)

(Chevron), because the statute does not

answer these specific issues, EPA has

discretion to provide a reasonable

interpretation.

Neither the decision in Virginia, nor

the body of caselaw upon which it

relies, addresses this issue. Rather, these

cases address solely the division

between the States and EPA regarding

the initial identification of control

measures necessary to attain the

ambient air quality standards. The issue

before the court in Virginia was whether

EPA had offered States a choice in

selecting control measures or instead

had mandated the adoption of a specific

control measure. Relying on Train v.

NRDC, 421 U.S. 60, 95 S.Ct. 1470, 43

L.Ed.2d 731 1975), the Virginia court

found that under title I of the CAA, EPA

is required to establish the overall air

quality standards, but the States are

primarily responsible for determining

the mix of control measures needed to

meet those standards and the sources

that must implement controls, as well as

the applicable level of control for those

sources. The EPA must then review the

State’s determination only to the extent

of assuring that the overall air quality

standards are met. If EPA determines

that the SIP’s mix of control measures

does not result in achieving the overall

air quality standards, EPA is required to

disapprove the SIP and promulgate a

FIP, under which EPA selects the

sources for emissions reductions

(Virginia, 108 F.3d at 1407–08, citing

Train v. NRDC, 421 U.S. 60, 95 S.Ct.

1470, 43 L.Ed.2d 731 (1975); Union

Electric Co. v. EPA, 427 U.S. 246, 96

S.Ct. 2518, 49 L.Ed.2d 474 (1976)). This

line of cases, which focuses on the

selection of controls, does not address

whether EPA or the States—in the first

instance—should determine the

aggregate amount of reductions

necessary to address interstate transport.

Moreover, NRDC v. Train addresses

State plans for purposes of intrastate

emissions planning. In determining that

States have the primary authority for

determining the control measures

needed to attain the standard, the court

relied on section 107(a) of the CAA,

which provided (and still provides) that:

Each State shall have the primary

responsibility for assuring air quality within

the entire geographic area comprising such

State by submitting an implementation plan

which will specify the manner in which

national primary and secondary ambient air

quality standards will be achieved and

maintained within each air quality region in

such State.’’

(421 U.S. at 64, 95 S.Ct at 1474–75

(emphasis added)).

Thus, the underlying support for the

court’s determination in Train v. NRDC

applies only where a State is

determining the mix of controls within

its boundaries, not to the broader task of

determining the aggregate emissions

reductions needed in conjunction with

emissions reductions from a number of

other States in order to address the

impact of transported pollution on

downwind States. 16

Although the cases to date have not

addressed directly whether it is the

province of EPA or the States to

determine the aggregate amounts of

emissions to be prohibited (and hence,

the amounts that may remain—i.e., the

emissions budgets), EPA believes it

reasonable to interpret the ambiguity in

section 110(a)(2)(D)(i)(I) to include this

determination among EPA’s

responsibilities, particularly in the

current circumstances. Determining the

overall level of air pollutants allowed to

be emitted in a State is comparable to

determining overall standards of air

quality, which the courts have

recognized as EPA’s responsibility, and

is distinguishable from determining the

particular mix of controls among

individual sources to attain those

standards, which the caselaw identifies

as a State responsibility. In Train, a

State was required to assure that its own

air quality attained overall air quality

standards and to implement emissions

controls to do so. Under these

circumstances, the court clarified that

while the responsibility for determining

the overall air quality standards was

EPA’s, the responsibility for

determining the specific mix of controls

designed to achieve that air quality was

the State’s. By comparison, as stated

earlier, a transport case, under section

110(a)(2)(D)(i), does not concern any

requirement of the upwind State to

assure that its own air quality attains

overall air quality standards. Rather, a

transport case concerns the upwind

State’s requirement to assure that its

emissions are reduced to a level that

will not contribute significantly to

nonattainment downwind. Determining

this overall level of reductions for the

upwind State is analogous to

determining overall air quality

standards, and, thus, should be the

responsibility of EPA.

Once EPA determines the overall

level of reductions (by assigning the

aggregate amounts of emissions that

must be eliminated to meet the

requirements of section 110(a)(2)(D)), it

falls to the State to determine the

appropriate mix of controls to achieve

those reductions. Unlike the regulation

at issue in Virginia, today’s regulation

establishing emission budgets for the

States does not limit the States to one

set of emission controls. Rather, the

States will have significant discretion to

choose the appropriate mix of controls

to meet the emissions budget. The EPA

has based the aggregate amounts to be

prohibited on the availability of a subset

of cost-effective controls that are among

the most cost effective available. As

explained elsewhere in this final rule

and the NPR, the State may choose from

a broader menu of cost-effective,

reasonable alternatives, including some

(e.g., vehicle inspection and

maintenance programs and reformulated
57370 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

gasoline) that may even be more

advantageous in light of local concerns.

The task of determining the

reductions necessary to meet section

110(a)(2)(D) involves allocating the use

of the downwind States’ air basin. This

area is a commons in the sense that the

contributing State or States have a

greater interest in protecting their local

interests than in protecting an area in a

downwind State over which they do not

have jurisdiction and for which they are

not politically accountable. Thus, in

general, it is reasonable to assume that

EPA may be in a better position to

determine the appropriate goal, or

budget, for the contributing States,

while leaving to the contributing States’

discretion to determine the mix of

controls to make the necessary

reductions.

The EPA’s decision to assign the

budgets in the final rule is particularly

reasonable. Today’s rulemaking

involves almost half the States in the

Nation, and although these States

participated in OTAG beginning more

than 3 years ago, they still have not

agreed on whether particular upwind

States should be treated as having

sources whose emissions contribute

significantly to downwind

nonattainment, what the aggregate level

of emissions reductions should be, or

what the State-by-State reductions

should be. The sharply divergent

positions taken by the States in their

comments on the NPR and SNPR raise

doubts that those disagreements could

ever be resolved by consensus. It is most

efficient—indeed necessary—for the

Federal government to establish the

overall emissions levels for the various

States. This is particularly true for an

interstate pollution problem such as the

one being dealt with in this action

where the downwind areas at issue are

affected by pollution coming from

several States and the actions taken by

each of the concerned States could have

an effect on the appropriate action to be

taken by another State. For example, if

EPA did not specify the emissions to be

prohibited from each of the various

States affecting New York City, each of

those States might claim it could reduce

its emissions less provided other States

did more. Or, a State close to New York

might assert that it could just as

effectively deal with its contribution to

New York through additional VOC,

rather than NOX, reductions and submit

a section 110(a)(2)(D) SIP based on a

VOC-control rather than NOX-control

strategy. These choices, however, even

assuming they were valid, necessarily

relate to the choices that would need to

be made by the other upwind States

(e.g., Pennsylvania’s choice of a VOCdominated 110(a)(2)(D) control strategy

to deal with its contribution to New

York could affect what Ohio or New

Jersey would need to do to deal with

their own contributions by lowering the

overall level of NOX reductions being

obtained throughout the pertinent

region). Where many States are involved

and the choices of each individual State

could affect the choices and decisions of

the other States the need for initial

federal action is manifest. The EPA’s

action to determine the amount of NOX

emissions that each of the States must

prohibit in this widespread geographic

area is needed to enable the States to

decide expeditiously how to achieve

those reductions in an efficient manner

that will not undermine the actions of

another State. By notifying each State in

advance of its reduction requirements,

EPA enables each State to develop its

plan with full knowledge of the amount

and kind of reductions that must be

achieved both by itself and other

affected States. The EPA’s action

provides the minimum framework

necessary for a multi-state solution to a

multi-state problem while preserving

the maximum amount of state flexibility

in terms of the specific control measures

to be adopted to achieve the needed

emission reductions. The

reasonableness of EPA’s approach to the

interstate ozone transport problem was

recently recognized by a US Court of

Appeals in the context of upholding

EPA’s redesignation of the Cleveland

ozone nonattainment area to attainment

in light of EPA’s approach to the

regional transport problem. In the

course of doing so the court rejected the

contention that a separate analysis of

the current adequacy of the Cleveland

SIP under section 110(a)(2)(D) was

required as a prerequisite to

redesignation. The court, after

describing the November 7, 1997

proposed SIP call and the path EPA was

on to deal with this multi-state regional

problem, upheld EPA’s redesignation

and stated that ‘‘[w]e find that the EPA’s

approach to the regional transport

problem is reasonable and not arbitrary

or capricious.’’ Southwestern

Pennsylvania Growth Alliance v.

Browner, 144 F.3d 984, 990 (6th Cir.

1998).

As noted above, commenters have

argued that if EPA determines to issue

any SIP call, the SIP call must be more

general (i.e., one that simply requires

revised SIPs from upwind areas) and not

specify the amounts of NOX emissions

that those areas must prohibit. However,

if EPA issued a general SIP call and an

upwind State responded by submitting

an inadequate SIP revision, EPA would

disapprove that SIP, and in the

disapproval rulemaking, EPA would be

obliged to justify why the submitted SIP

was unacceptable. Without determining

an acceptable level of NOX reductions,

the upwind State would not have

guidance as to what is an acceptable

submission. The EPA’s determination,

as part of the issuance of the SIP call,

of the amounts of NOX emissions the

SIPs must prohibit obviously provides

for more efficient and smooth-running

administrative processes at both the

State and Federal levels. For the same

reasons that EPA believes it is

appropriate for the Agency to establish

the emissions budgets under the

authority of section 110(a)(2)(D) and

(k)(5), EPA believes that it is necessary

to do so through a rule under the

general rulemaking authority of section

301(a). Setting such a rule is necessary,

as a practical matter, for the

Administrator’s effective

implementation of section 110(a)(2)(D).

See NRDC v. EPA, 22 F.3d 1125, 1146–

48. Without such a rule the States could

be expected to submit SIPs reflecting

their conflicting interests, which could

result in up to 23 separate SIP

disapproval rulemakings in which EPA

would need to define the requirements

that each of those States would need to

meet in their later, corrective SIPs. That

in turn would trigger a new round of SIP

rulemakings to judge those corrective

SIPs. The delay attendant to that process

would thwart timely attainment of the

ozone standards.

2. Authority and Process for Requiring

SIP Submissions under the 8-Hour

Ozone NAAQS

a. Authority for Requiring SIP

Submissions under the 8-Hour NAAQS.

(1) SIP Submissions Under CAA Section

110(a)(1). In the NPR and SNPR, EPA

proposed to require the 23 upwind

jurisdictions to submit SIP revisions to

reduce emissions that exacerbate ozone

problems in downwind States under the

8-hour ozone NAAQS, as well as the 1-

hour NAAQS. The EPA recognized that

under the 8-hour NAAQS, areas have

not yet been designated as attainment,

nonattainment, or unclassifiable, and

are not yet required to have SIPs in

place. Even so, EPA proposed that

upwind areas be required to submit SIPs

meeting the requirements of section

110(a)(2)(D)(i)(I) with respect to the 8-

hour NAAQS.

In today’s action, EPA is confirming

its view that it has authority under the

8-hour NAAQS to require SIP submittals

under section 110(a)(2)(D)(i)(I) to reduce

NOX emissions by the prescribed

amounts. Section 110(a)(1) provides, in

relevant part—
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57371

17As quoted above, section 172(b) refers to

‘‘applicable requirements of * * * section

110(a)(2).’’ This reference appears to mean those

requirements of section 110(a)(2) that either (i)

relate to all SIP submissions, such as the

requirement for reasonable notice and public

hearing in the language at the beginning of section

110(a)(2); or (ii) relate particularly to SIP

submissions required for nonattainment areas, but

that have not yet been submitted by the State.

18Section 110(a)(2)(D)(i)(I) further provides that a

SIP must prohibit emissions that ‘‘interfere with

maintenance by * * * any other State.’’

Each State shall * * * adopt and submit to

the Administrator, within 3 years (or such

shorter period as the Administrator may

prescribe) after the promulgation of a

national primary ambient air quality standard

(or any revision thereof) * * * a plan which

provides for implementation, maintenance,

and enforcement of such primary standard in

each (area) within such State.

Section 110(a)(2) provides, in relevant

part—

Each implementation plan submitted by a

State under this Act shall be adopted by the

State after reasonable notice and public

hearing. Each such plan shall [meet certain

requirements, including those found in

section 110(a)(2)(D)].

The provisions of section 110(a)(1)

and (a)(2) apply by their terms to all

areas, regardless of whether they have

been designated as attainment,

nonattainment, or unclassifiable under

section 107. The plain meaning of these

provisions, read together, is that SIP

revisions are required under the revised

NAAQS within 3 years of the date of

revision, or earlier if EPA so requires,

and that those SIP revisions must meet

the requirements of section 110(a)(2),

including subparagraph (D).

That the SIP submission requirements

of section 110(a)(1) are triggered by the

promulgation of a new or revised

NAAQS is made even clearer by

comparing section 172(b), which applies

by its terms only to areas that have been

designated nonattainment under section

107. Section 172(b) provides, in relevant

part—

At the time the Administrator promulgates

the designation of any area as nonattainment

with respect to a [NAAQS] under section

107(d) * * *, the Administrator shall

establish a schedule according to which the

State containing such area shall submit a

plan or plan revision * * * meeting the

applicable requirements of subsection (c) of

this section and section 110(a)(2) * * * Such

schedule shall at a minimum, include a date

or dates, extending no later than 3 years from

the date of the nonattainment designation, for

the submission of a plan or plan revision

* * * meeting the applicable requirements of

subsection (c) of this section and section

110(a)(2) * * *

Section 172(b) establishes the

schedule for submissions due with

respect to nonattainment areas under

sections 172(c) and 110(a)(2). The

section 172(c) requirements apply only

with respect to areas designated

nonattainment.17

In the NPR, EPA proposed that

section 110(a)(1) mandates SIP

submissions meeting the requirements

of section 110(a)(2)(D) and provides full

authority for EPA to establish a

submission date within 3 years of the

July 18, 1997 8-hour ozone NAAQS

promulgation date (62 FR 38856

(NAAQS rulemaking): 62 FR 60325

(NOx SIP call NPR)). The EPA further

asserted in the NPR that EPA has the

authority to establish different submittal

schedules for different parts of the

section 110(a)(1) SIP revision, and that

EPA may require the section

110(a)(2)(D) submittal first so that

upwind reductions may be secured at an

earlier stage in the regional SIP planning

process (62 FR 60325). Subsections (ii)

and (iii) of this section further

elaborates on the reasoning underlying

EPA’s decision to retain its proposal to

require SIP submissions under section

110(a)(2)(D) for the 8-hour standard.

(2) Commenters and the Definition of

‘‘Nonattainment.’’ Commenters

challenged several aspects of EPA’s

proposal to evaluate the contribution of

upwind areas under the 8-hour NAAQS.

Commenters asserted that section

110(a)(2)(D)(i) applies to constrain

emissions from upwind sources only

with respect to downwind areas that are

designated nonattainment. According to

these commenters, until EPA designates

areas nonattainment under the 8-hour

NAAQS, EPA has no authority to

require SIP submissions, under section

110(a)(1), from upwind areas with

respect to the 8-hour NAAQS. One

commenter pointed out that the new

source review requirements and ozone

nonattainment requirements enacted in

the 1990 Amendments apply only to

areas designated nonattainment.

The EPA disagrees with this

comment. Section 110(a)(2)(D)(i)(I)

provides that a SIP must prohibit

emissions that ‘‘contribute significantly

to nonattainment in * * * any other

State.’’ 18 The provision does not, by its

terms, indicate that this downwind

‘‘nonattainment’’ must already have

been designated under section 107 as a

nonattainment ‘‘area.’’ If the provision

were to employ the term ‘‘area’’ in

conjunction with the term

‘‘nonattainment,’’ then it would have to

be interpreted to apply only to areas

designated nonattainment. Other

provisions of the CAA do employ the

term ‘‘area’’ in conjunction with

‘‘nonattainment,’’ and these provisions

clearly refer to areas designated

nonattainment (e.g., sections

107(d)(1)(A)(i), 181(b)(2)(A),

211(k)(10)(D)). Similarly, the provisions

to which the commenter appeared to

refer—section 172(b)/172(c)(5) (new

source review) and section 181(a)(1)/182

(classified ozone nonattainment area

requirements)—by their terms apply to

a nonattainment ‘‘area.’’ In contrast,

section 110(a)(2)(D) refers to only

‘‘nonattainment,’’ not to a

nonattainment ‘‘area.’’

By the same token, section 176A(a)

authorizes EPA to establish a transport

region whenever ‘‘the Administrator has

reason to believe that the interstate

transport of air pollutants from one or

more States contributes significantly to

a violation of a [NAAQS] in one or more

other States.’’ This reference to ‘‘a

violation of a [NAAQS]’’ makes clear

that EPA is authorized to form a

transport region when an upwind State

contributes significantly to a downwind

area with nonattainment air quality,

regardless of whether the downwind

area is designated nonattainment. The

EPA believes that section 110(a)(2)(D)

should be read the same way in light of

the parallels between section

110(a)(2)(D) and section 176A(a). Both

provisions address transport and both

are triggered when emissions from an

upwind area ‘‘contribute significantly’’

downwind. It seems reasonable to apply

a consistent approach to the type of

affected downwind area, which would

mean interpreting the term

‘‘nonattainment’’ in section 110(a)(2)(D)

as synonymous with the phrase ‘‘a

violation of a [NAAQS]’’ in section

176A(a). The CAA contains other

provisions, as well, that refer to the

factual, air quality status of a particular

area as opposed to its designation status.

These provisions include, among others,

(i) sections 172(c)(2) and 171(1), the

reasonable further progress requirement,

which requires nonattainment SIPs to

provide for ‘‘such annual incremental

reductions in emissions * * * as * * *

may * * * be required * * * for the

purpose of ensuring attainment of the

[NAAQS]’’ (emphasis added); and (ii)

section 182(c)(2), the attainment

demonstration requirement, which

mandates a ‘‘demonstration that the

[SIP] * * * will provide for attainment

of the [NAAQS]’’ (emphasis added). The

emphasized terms clearly refer to air

quality status. In a series of notices in

the Federal Register, EPA relied on

these references to air quality status in

determining that areas seeking to

redesignate from nonattainment to

attainment did not need to complete

ROP SIPs or attainment

demonstrations—even though those

requirements generally applied to areas
57372 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

19Similarly, EPA believes that the term

‘‘maintenance’’ in another clause of section

110(a)(2)(D)(i)(I) refers to air quality status as well.

This clause includes only the term ‘‘maintenance,’’

and does not include the term ‘‘area.’’

20See ‘‘Re-issue of the Early Planning Guidance

for the Revised Ozone and Particulate Matter (PM)

National Ambient Air Quality Standards

(NAAQS),’’ memorandum from Sally L. Shaver,

dated June 16, 1998.

21Section 110(a)(2)(D) provides that areas

designated nonattainment must submit SIPs in

accordance with ‘‘part D’’ (which includes section

172). Section 172(b) requires EPA to establish a

schedule for designated nonattainment areas to

meet the requirements of sections 172(c) and

designated nonattainment—as long as

the air quality for those redesignating

areas was, in fact, in attainment. See

‘‘State Implementation Plans; General

Preamble for the Implementation of

Title I of the Clean Air Act Amendments

of 1990; Proposed Rule,’’ 57 FR 13498,

13564 (April 16, 1992); ‘‘Determination

of Attainment of Ozone Standard for

Salt Lake and Davis Counties, Utah, and

Determination Regarding Applicability

of Certain Reasonable Further Progress

and Attainment Demonstration

Requirements: Direct Final Rule,’’ 60 FR

30189, 30190 (June 8, 1995); and

‘‘Determination of Attainment of Ozone

Standard for Salt Lake and Davis

Counties, Utah, and Determination

Regarding Applicability of Certain

Reasonable Further Progress and

Attainment Demonstration

Requirements: Final Rule,’’ 60 FR

36723, 36724 (July 18, 1995). The EPA’s

interpretation was upheld by the Court

of Appeals for the 10th Circuit, in Sierra

Club v. EPA, 99 F.3d 1551, 1557 (10th

Cir. 1996).

Accordingly, EPA believes it clear

that the reference in section

110(a)(2)(D)(i)(I) to ‘‘nonattainment’’

refers to air quality, not designation

status. The EPA believes this matter is

clearly resolved by reference to the

terms of the provision itself, so that

under the first step of the Chevron

analysis, no further inquiry is needed.

If, however, it were concluded that the

provision is ambiguous on this point,

then EPA believes that, under the

second step in the Chevron analysis,

EPA should be given deference for any

reasonable interpretation. Interpreting

‘‘nonattainment’’ to refer to air quality is

reasonable for the reasons described

above.19

The structure of the schedules for

requiring SIP submissions and

designating areas nonattainment

provides support for EPA’s

interpretation. As noted above, section

110(a)(1) requires States to submit SIPs

covering all their areas—regardless of

whether designated, or how

designated— within 3 years of a

NAAQS revision and requires that those

SIPs include provisions meeting the

requirements of section 110(a)(2)(D).20

When a new or revised NAAQS is

promulgated, section 107(d)(1)

authorizes a process of up to 3 years for

designations. States must recommend

designations within one year of

promulgation of a new or revised

NAAQS and EPA must designate areas

within 2 years of promulgation; EPA

may take up to 3 years to designate areas

if insufficient information prevents

designations within 2 years. In the case

of the 8-hour ozone NAAQS, Congress

provided specific legislation for

designations (Pub. L. 105–178 § 6103).

Under this new legislation, States are

provided 2 years to make

recommendations and EPA must

designate areas within 1 year of the time

State recommendations are due.

Because of this legislation, designations

must occur 3 years following

promulgation of the NAAQS (July 2000).

The EPA believes that it is not sensible

to interpret the term ‘‘nonattainment’’ in

section 110(a)(2)(D)(i)(I) to refer to

nonattainment designations because

those designations may not be made

until 3 years after the promulgation of

a new or revised NAAQS, and the

section 110(a)(2)(D) submittals are due

within 3 years.

Further, interpreting the reference to

‘‘nonattainment’’ as a reference to air

quality, and not designation, is

consistent with the air quality goals of

section 110(a)(2)(D) and the CAA as a

whole. In the present case, it is clear

from air quality monitoring and

modeling that large areas of the eastern

part of the United States are in violation

of the 8-hour NAAQS, and it is also

clear from air quality modeling studies

that NOX emissions from sources in

upwind States contribute to those air

quality violations. The EPA currently

has available all the information that it

needs to determine whether upwind

States should be required to revise their

SIPs to implement appropriate

reductions in NOX emissions. The

designation process will clarify the

precise boundaries of the downwind

areas, but because ozone is a regional

phenomenon, information as to the

precise boundaries of the downwind

areas is not necessary to implement the

requirements of section 110(a)(2)(D)(i).

As a result, no air quality purpose will

be served by waiting until the

downwind areas are designated

nonattainment.

On the contrary, taking action now is

necessary to protect public health. As

described in Section I.G., the regional

NOX reductions required under today’s

action will allow numerous areas

currently in violation of the 8-hour

NAAQS to attain that standard. For the

millions of people living in those areas,

today’s action will advance the date by

which these areas will meet the revised

ozone standard. Taking action now is

particularly important because one of

the sub-population groups at higher risk

to ozone health effects is children who

are active and spend more time

outdoors during the summer months

when ozone levels are elevated.

(3) EPA’s Authority to Require Section

110(a)(2)(D) Submissions in Accordance

with section 110(a)(1). Commenters

argue that sections 110(a)(1), (a)(2), and

172(b) should be read so that only

requirements under section 110(a)(2)

that are unrelated to nonattainment are

due under the section 110(a)(1)

timetable. These commenters contend

that requirements under section

110(a)(2) that are related to

nonattainment—including section

110(a)(2)(D)—are due under the section

172(b) timetable, that is, within 3 years

of the designation of areas as

nonattainment. In support, these

commenters rely on language in section

110(a)(1) indicating that the

submissions are for plans for air quality

regions ‘‘within such State.’’ Finally,

certain commenters cite as further

support for their position the definition

of the term ‘‘nonattainment’’ as found in

section 107(d)(1)(A), claiming that the

definition includes interstate transport

areas.

As noted above, section 110(a)(1)

provides that States must submit SIP

revisions providing ‘‘for the

implementation, maintenance and

enforcement’’ of the NAAQS in each

area of the State within 3 years (or a

shorter time prescribed by the

Administrator) following promulgation

of a new or revised NAAQS. Section

110(a)(2) then sets forth the applicable

elements of a SIP. These provisions

apply to all areas within the State,

regardless of designation. Section 172(b)

establishes a SIP submission schedule

for nonattainment areas. It provides that

at the time EPA designates areas as

nonattainment, EPA shall establish a

SIP submission schedule for the

submission of a SIP meeting the

requirements of section 172(c).

While EPA agrees that there is overlap

between the submission requirements

under sections 110(a)(1)–(2) and 172(c),

EPA believes that the plain language of

section 110(a)(1)–(2) authorizes EPA to

require the section 110(a)(2)(D) SIPs on

the schedule described today, and that

there is nothing to the contrary in

section 172. Sections 110(a)(2) and 172

contain cross-references to each other.21
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57373

110(a)(2); section 172(c)(7) requires that

nonattainment SIPs shall meet the requirements of

section 110(a)(2).

22 In other situations, EPA has indicated that

certain elements of section 110(a)(2) would be

better addressed in accordance with the timeframe

established in section 172. See e.g., 60 FR 12492,

12505 (March 7, 1995) Proposed Requirements for

Implementation Plans and Ambient Air Quality

Surveillance for Sulfur Oxides (Sulfur Dioxide)

National Ambient Air Quality Standard.

These cross-references indicate that

under certain circumstances, the section

110(a)(2)(D) submittal may be required

under section 110(a)(1); and under other

circumstances, the section 110(a)(2)(D)

submittal may be required under section

172(b). These cross-references are

particularly relevant with respect to

nonattainment areas, which are subject

to both sections 110(a) (1) and (2) and

172. In the current situation, EPA

believes that it is appropriate to require

the submissions to meet section

110(a)(2)(D) in accordance with the

schedule in section 110(a)(1) rather than

under the schedule for nonattainment

areas in section 172(b).22

The EPA has provided that, for the

revised ozone and particulate matter

NAAQS, States must assess their section

110 SIPs by July 18, 2000 to ensure that

they adequately provide for

implementing the revised standards. See

Re-issue of the Early Planning Guidance

for the Revised Ozone and Particulate

Matter (PM) National Ambient Air

Quality Standards (NAAQS),

memorandum from Sally L. Shaver,

dated June 16, 1998. The EPA

recognized that the section 110 SIP

should generally be sufficient to address

the revised NAAQS. However, the

Agency noted three areas that the States

particularly needed to assess, including

whether the SIP adequately addressed

section 110(a)(2)(D). The EPA also

provided that the States should submit

revisions to address section 110(a)(2)(D)

on the timeframe established by the

final NOX SIP call, when issued. The

submittal date that EPA has specified in

the final NOX SIP call rule is consistent

with both the Early Planning Guidance

and with section 110(a)(1) and (2) of the

CAA.

The EPA acknowledges that it has not

historically required an affirmative

submission under section 110(a)(2)(D),

applicable to specific sources of

emissions, in response to the

promulgation of a new or revised

NAAQS. In part, this is because

sufficient technical information was not

available to determine which sources

‘‘contribute significantly’’ to

nonattainment in a downwind area. In

the absence of such a determination,

States were unable to regulate sources

under this provision in any meaningful

way. However, based on the many

analyses performed over the last several

years, EPA believes that there is now

affirmative information regarding

significant contribution to ozone

violations in the eastern portion of the

country; in light of that evidence, it

would not be appropriate to defer action

under section 110(a)(2)(D) until a later

time.

Moreover, as noted above, the section

172(c) SIP submissions apply only to

areas designated nonattainment.

Specifically, section 172(b) provides

that ‘‘[a]t the time’’ EPA designates an

area as nonattainment, EPA shall set a

schedule ‘‘according to which the State

containing such area shall submit’’ SIPs.

Section 171(2) provides further

clarification by providing that for

purposes of part D of title I of the CAA

(CAA sections 171–193) ‘‘[t]he term

‘nonattainment area’ means, for any air

pollutant, an area which is designated

‘nonattainment’ with respect to that

pollutant within the meaning of section

107(d).’’ By its terms then, section 172

does not apply to areas designated

attainment or unclassifiable (even if

such areas are not attaining the

standard) or for areas not yet designated.

Thus, section 110(a)(1) provides the

only submission schedule for areas not

designated nonattainment. For those

areas, the commenters’ argument that

section 172(b) should establish the

timetable for section 110(a)(2)(D)(i) SIPs

clearly fails. Since certain portions of

the 23 jurisdictions covered by this rule

likely will not be designated

nonattainment for the 8-hour standard,

EPA believes that the section 110(a)(1)

schedule is the only schedule (and thus

is the reasonable schedule) to follow for

purposes of the SIP call.

Furthermore, contrary to the

commenters’ assertions, the definition

of nonattainment does not broadly

include areas that contribute to

nonattainment in a downwind State.

The definition of nonattainment

includes areas that have monitored

violations of the standard and areas that

‘‘contribute to ambient air quality in a

nearby area’’ that is violating the

standard (section 107(d)(1)(A)(i)

(emphasis added)). Thus, only ‘‘nearby’’

areas that contribute to violations of a

standard will be included in the

nonattainment designation; areas

contributing to longer-range transport

will not be designated nonattainment

based solely on that longer-range

transport. Therefore, they will not be

subject to section 172(c) requirements

and timing.

The commenters argue that EPA’s

position that section 110(a)(1) governs

the section 110(a)(2)(D) SIP submittal

schedule leads to the absurd result that

upwind areas will be required to submit

SIPs dealing with their contribution to

a nonattainment problem downwind

before the downwind area will be

required to submit SIPs under section

172(b). The commenters explain that

section 110(a)(2) requires SIP submittals

on a faster timetable (within 3 years

from the date of promulgation or

revision of a NAAQS) than section

172(b) (within 3 years from the date of

designation as nonattainment). The

commenters also contend that section

107 provides that States have the

primary responsibility for ensuring

attainment within their boundaries;

only after a State implements all

statutorily required and necessary

measures can it pursue reductions in

other areas through a SIP call or section

126. The commenters contend that the

SIP call is contrary to the plain language

of section 107 and congressional intent

because it would require upwind areas

to implement controls before the

downwind area has implemented all

statutorily required or necessary

controls.

While it is true that plans to meet the

emissions budget for the SIP call will be

due prior to nonattainment designations

and attainment plans for areas

designated nonattainment for the 8-hour

standard, EPA does not consider this

result to be absurd in the present case.

The CAA, at least since its

amendment in 1970, has required States

to regulate ozone. For more than the

past 25 years, States have focused on the

adoption and implementation of local

controls for the purpose of bringing

nonattainment areas into attainment.

Thus, historically, the downwind

nonattainment areas have borne the

brunt of the control obligations through

the implementation of local controls. In

comparison, areas in attainment of the

NAAQS, but upwind of nonattainment

areas, have not been required to

implement controls designed to

ameliorate the air quality problems

experienced by their downwind

neighbors.

Since the CAA Amendment of 1977,

designated nonattainment areas have

been subject to specific local control

obligations, such as vehicle I/M and, for

stationary sources, the requirement to

implement RACT. The CAA

Amendments of 1990 tightened these

control obligations for many areas.

Moderate, serious, severe and extreme

areas were required to reduce emissions

by 15 percent between 1990 and 1996.

In addition, each serious, severe and

extreme area is required to achieve 9

percent reductions over the succeeding

3 year periods until the area attains the
57374 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

23Although the SIP call will provide a benefit to

a wide number of areas, the focus of the SIP call

is to reduce boundary conditions for a number of

areas that will have difficulty attaining either the 1-

hour or 8-hour standard (or both) without the

benefit of reductions from outside the

nonattainment area. Based on current monitoring

data and modeling, EPA predicts that there will be

a number of areas that are meeting the 1-hour

standard that will be designated nonattainment for

the 8-hour standard. The EPA further predicts that

many of these areas will come back into attainment

due solely to the emission reductions achieved by

the NOX SIP call. However, this incidental benefit—

which likely will occur without the need for local

emission reductions—does not preclude EPA from

requiring the SIP call reductions, which are needed

to help other more seriously polluted areas that

have long-standing pollution problems.

24Maine, New Hampshire, and Vermont are the

only downwind States that are not subject to

today’s action.

standard. Additional requirements, such

as the use of RFG and the use of vapor

recovery devices on gasoline pumps, are

also required for certain areas (see

generally, CAA section 182 and, e.g.,

section 211(k)). Thus, downwind areas

with nonattainment problems under the

1-hour NAAQS are under current

obligations to submit SIP revisions

containing local control measures for

that standard. For these areas, local

reductions needed to meet the 1-hour

standard are already occurring and will

be achieved prior to or on the same

schedule as reductions States may

require in response to the SIP call.

Furthermore, in many of the

downwind areas, States have been

taking action to reduce ozone levels for

many years in order to meet the 1-hour

ozone NAAQS. Although the fact that

the 8-hour ozone NAAQS is a new form

of the ozone standard, however, should

not obscure the fact that the downwind

States have been making efforts to

reduce ozone levels for decades. The

EPA believes that the history of

implementation by downwind areas of

ozone pollution controls further

mitigates the commenters’ argument

that it is absurd to require upwind areas

to implement controls in advance of

downwind attainment demonstrations

under the 8-hour NAAQS.23

Moreover, virtually all of the

downwind States affected by today’s

rulemaking, due to 8-hour ozone

nonattainment or maintenance

problems, are themselves upwind

contributors to problems further

downwind, and, thus, are subject to the

same requirements as the States further

upwind.24 The reductions these

downwind States must implement due

to their additional role as upwind States

will help reduce their own 8-hour ozone

problems on the same schedule as

emissions reductions for the upwind

States. Accordingly, for the most part,

this rulemaking does not require

upwind areas to take action in advance

of any action by downwind areas to

ameliorate the downwind problems.

Finally, even if EPA were requiring

upwind States to take action to reduce

downwind nonattainment and

maintenance in advance of action by the

downwind States, this would simply

require upwind areas to take the first

step by developing SIPs to eliminate

their significant contribution to the

downwind problem. The downwind

areas will be required to take the next

step by developing SIPs that address

their share. Generally, an agency may

resolve a problem (in this case,

downwind nonattainment) on a step-bystep basis (see e.g., Group Against Smog

and Pollution, Inc. v. EPA, 665 F.2d

1284, 1291–92 (D.C. Cir. 1981)).

A commenter has observed that under

section 110(a)(1), EPA may authorize

section 110(a)(2) submittals as late as 3

years after revision of a NAAQS, which,

in this case, would run until July 2000.

The Early Planning Guidance, described

above, indicates that States are allowed

until July 2000 to make submissions

concerning other elements of section

110(a)(2). However, as described

elsewhere, EPA has determined that the

section 110(a)(2)(D) submittals should

be submitted by the end of September

1999 to assure that the required NOX

reductions will be implemented as

expeditiously as practicable, which EPA

has determined is no later than the May

1 start of the 2003 ozone season (see

Section V, below).

Citing section 107(a) of the CAA, the

commenters assert that the CAA

requires downwind areas to fully adopt

and implement all statutorily required

or necessary measures before EPA can

require upwind areas to control

emissions. Section 107 provides that

States shall have the primary

responsibility for assuring air quality

within the State by submitting a plan

that specifies how the NAAQS will be

achieved and maintained in the State.

The commenters attempt to read this

statement regarding a State’s authority

to choose the mix of control measures

within State boundaries as barring the

control of emissions from upwind

States.

This provision may be read as

focusing on the State-Federal balance in

controlling criteria pollutants, such as

ozone, not any upwind-State,

downwind-State balance. The provision

indicates that although EPA may

promulgate Federal measures that

provide reductions to help States reach

attainment, States bear the ultimate

responsibility for assuring attainment.

Further, this provision may be read to

indicate that States may choose the mix

of controls to reach attainment within

their own boundaries. Nothing in this

provision purports to address the need

for upwind controls. By comparison,

section 110(a)(2)(D) affirmatively

requires States to submit a SIP

prohibiting emissions that significantly

contribute to downwind nonattainment

or interfere with maintenance of the

NAAQS. Thus, the statute, read as a

whole, contemplates that interstate

transport will be addressed as part of

the downwind States’ attainment

responsibilities. Indeed, determining the

upwind area’s share of the problem is

necessary in order for downwind

attainment planning. In the absence of

the upwind reductions that will be

achieved, the downwind area would be

required to submit an attainment plan to

demonstrate attainment regardless of

cost and without benefit of the

reduction of upwind emissions that

significantly contribute to

nonattainment. In light of the statute as

a whole, it is absurd to argue that

Congress intended downwind areas to

reduce emissions at any cost while

upwind sources that significantly

contribute to that nonattainment remain

unregulated. Congress attempted to

balance responsibilities, providing that

States could choose the mix of controls

within the State’s borders (CAA section

107(a)) and are ultimately responsible

for assuring attainment, but also

recognizing that emissions reductions

from upwind States may be needed for

attainment (CAA section 110(a)(2)(D)(i)).

b. Process for Requiring SIP

Submissions under the 8-Hour

Standard. The time by which the

section 110(a)(2)(D) SIP revision under

the 8-hour NAAQS must be submitted is

governed by section 110(a)(1), which

requires the SIP revision to be

‘‘adopt[ed] and submit[ed] to the

Administrator, within 3 years (or such

shorter period as the Administrator may

prescribe) after the promulgation of a

[NAAQS] (or any revision thereof) . . .

.’’ In the NPR, EPA indicated that the

SIP revision would be due by the end

of September 1999, which EPA expected

to be 12 months from the date of

completing today’s final rule. In today’s

action, EPA is confirming that the SIP

revision will be due September 30,

1999, for the reasons described below in

Section VI.A.1, Schedule for SIP

Revision.

3. Requirements of Section 110(a)(2)(D)

a. Summary. Today’s action is driven

by the requirements of CAA section

110(a)(2)(D). This provides that each SIP

must—
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57375

25 It should be reiterated that EPA relied on the

designated area solely as a proxy to determine

which areas have air quality in nonattainment. This

proxy is readily available under the 1-hour NAAQS

because areas have long been designated

nonattainment. The EPA’s reliance on designated

nonattainment areas for purposes of the 1-hour

NAAQS does not indicate that the reference in

section 110(a)(2)(D)(i)(I) to ‘‘nonattainment’’ should

be interpreted to refer to areas designated

nonattainment.

* * * contain adequate provisions—(I)

prohibiting, consistent with the provisions of

this title, any source or other type of

emissions activity within the State from

emitting any air pollutant in amounts which

will—(I) 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 * * *

According to section 110(a)(2)(D), the

SIP for each area, regardless of its

designation as nonattainment or

attainment (including unclassifiable),

must prohibit sources within the area

from emitting air pollutants in amounts

that will ‘‘contribute significantly’’ to

‘‘nonattainment’’ in a downwind State,

or that ‘‘interfere with maintenance’’ in

a downwind State.

b. Determination of Meaning of

‘‘Nonattainment’’ (1) Geographic Scope.

In determining the meaning and scope

of section 110(a)(2)(D), it is useful first

to determine the geographic scope of

‘‘nonattainment’’ downwind.

At proposal, EPA stated that it—

* * * proposes to interpret this term to

refer to air quality and not to be limited to

currently-designated nonattainment areas.

Section 110(a)(2)(D) does not refer to

‘‘nonattainment areas,’’ which is a phrase

that EPA interprets to refer to areas that are

designated nonattainment

under * * * section 107(d)(1)(A)(I) * * * .

Rather, the provision includes only the term

‘nonattainment’ and does not define that

term. Under these circumstances, EPA has

discretion to give the term a reasonable

definition, and EPA proposes to define it to

include areas whose air quality currently

violates the NAAQS, and will likely continue

[to violate in the future], regardless of the

designation of those areas * * *

(62 FR 60324).

To determine whether areas would

continue to violate in the future, EPA

proposed to take into account the

reductions that would result from

current CAA control requirements (apart

from controls that may be required

under section 110(a)(2)(D)). To take

these reductions into account, EPA

determined whether the area would be

in nonattainment in the future based on

air quality modeling that assumed CAAmandated reductions and that

accounted for growth. If an area would

reach attainment based on required

controls, EPA would not view that area

as having a nonattainment problem to

which any upwind areas may be

considered to contribute.

As explained earlier, in today’s

action, EPA has determined that for

purposes of the 8-hour NAAQS, the

reference to ‘‘nonattainment’’ should be

defined as EPA proposed. Thus, in

determining whether an upwind area

contributes significantly to

‘‘nonattainment’’ downwind, EPA

would evaluate downwind areas for

which monitors indicate current

nonattainment, and air quality models

indicate future nonattainment, taking

into account CAA control requirements

and growth.

For the 1-hour standard, EPA

proposed to define nonattainment to

include all grid cells within a county

when a monitor in that county indicated

nonattainment. Upon further study, EPA

found that in some instances, a

metropolitan area may consist of

numerous counties, only a few of which

contain monitors indicating

nonattainment. The EPA recognizes that

under the 1-hour NAAQS,

nonattainment boundaries are generally

used to describe the area with the

nonattainment problem; accordingly,

EPA believes that this geographic

vicinity offers an appropriate indication

of an area that may be expected to have

nonattainment air quality. The EPA

predicts that many 1-hour

nonattainment areas that currently

monitor nonattainment somewhere

within the area will remain in

nonattainment in 2007, in some cases

because of predicted violations in

counties that currently monitor

attainment. The EPA believes that the

entire area should be considered to be

in nonattainment until all monitors in

the area indicate attainment of the

NAAQS. Thus, in today’s action, EPA

used the designated nonattainment area

in determining the downwind

nonattainment problem.25

As noted above, commenters

disagreed with EPA’s view that the term

‘‘nonattainment’’ covers areas with air

quality that is currently in

nonattainment, regardless of

designation. The EPA’s response to

those comments is also set forth above.

(2) 2007 Projection Year. In the NPR,

EPA indicated that it would adopt the

year 2007 as the year for determining

whether areas achieved their required

NOX budget levels. Accordingly, in

determining whether downwind areas

should be considered to be, and remain

in, ‘‘nonattainment,’’ EPA would model

their air quality in 2007, based on the

implementation of CAA required

controls by that date, and growth in

emissions—generally due to economic

growth and greater use of vehicles—by

that date. At proposal, EPA adopted this

same approach with respect to both the

1-hour and the 8-hour NAAQS (62 FR

60325). The EPA is continuing this

approach.

c. Definition of Significant

Contribution. As indicated in the NPR,

neither the CAA nor its legislative

history provides meaningful guidance

for interpreting the term ‘‘contribute

significantly’’ under section

110(a)(2)(D)(i)(I).

(1) ‘‘Contribute.’’ The initial step in

defining the ‘‘contribute significantly’’

term is to determine the meaning of the

term ‘‘contribute.’’ In the NPR, EPA

stated that it believes this term should

be defined broadly, so that emissions

‘‘contribute’’ to nonattainment

downwind if they have an impact on

nonattainment downwind (62 FR

60325). Air quality modeling indicated

that emissions from the upwind States

clearly impact downwind

nonattainment problems; as a result,

EPA generally folded this step of

determining whether sources

‘‘contribute’’ to nonattainment

downwind into the step of determining

whether that contribution is

‘‘significant,’’ discussed below.

In addition, section 110(a)(2)(D)(i)(I)

requires the SIP to prohibit amounts of

emissions ‘‘which will contribute

significantly * * *’’ (emphasis added).

The EPA believes that the term ‘‘will’’

means that SIPs are required to

eliminate the appropriate amounts of

emissions that presently, or that are

expected in the future, contribute

significantly to nonattainment

downwind.

Because ozone is a secondary

pollutant formed as a result of complex

chemical reactions involving numerous

sources, it is not possible to determine

the downwind impact on each

individual source. In addition, ozone

generally results from the contributions

of numerous sources. As indicated in

the NPR:

[U]nhealthful levels of ozone result from

emissions of NOX and VOCs from thousands

of stationary sources and millions of mobile

sources [and consumer products and other

sources] across a broad geographic area. Each

source’s contribution is a small percentage of

the overall problem; indeed, it is rare for

emissions from even the largest single

sources to exceed one percent of the

inventory of ozone precursors even for a

single metropolitan area. Under these

circumstances, even complete elimination of

any given source’s emissions may well have

no measurable impact in ameliorating the

nonattainment problem. Rather, attainment

requires controls on numerous sources across

a broad area. Ozone is a regional scale
57376 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

problem that requires regional scale

reductions

(62 FR 60326).

Accordingly, EPA has adopted a

‘‘collective contribution’’ approach to

determining whether sources

‘‘contribute’’ to nonattainment

downwind: EPA determines the impact

downwind of emissions in the aggregate

from a particular geographic region. If

the aggregated emissions are considered

to contribute to nonattainment

downwind, then all of the emissions in

that region should be considered as

contributors to that nonattainment

problem. In today’s action, EPA is

continuing the same interpretation of

the term ‘‘contribute,’’ for the reasons

just described.

(2) ‘‘Significantly’’. (a) Notice of

Proposed Rulemaking. In the NPR, EPA

proposed a ‘‘weight-of-evidence,’’ or

multi-factor, approach for determining

whether a contribution is ‘‘significant.’’

The EPA proposed two separate

interpretations for the term ‘‘contribute

significantly,’’ which had implications

as to which factors were to be

considered in what parts of the analysis.

Under the first interpretation,

significant contribution is determined

with reference to—

* * * factors concerning amounts of

emissions and their ambient impact,

including the nature of how the pollutant is

formed, the level of emissions and emissions

density (defined as amount of emissions per

square mile) in the particular upwind area,

the level of emissions in other upwind areas,

the amount of contribution to ozone in the

downwind area from the upwind areas, and

the distance between the upwind sources and

the downwind nonattainment problem.

Under this approach, when emissions and

ambient impact reach a certain level, as

assessed by reference to the factors identified

above, those emissions would be considered

to ‘‘contribute significantly’’ to

nonattainment.

(62 FR 60325).

Under this interpretation, after

identifying amounts of emissions that

constitute a significant contribution,

EPA then determines the amount of

emissions reductions necessary to

adequately mitigate these contributions.

This determination entails—

* * * [e]valuation of the costs of available

measures for reducing upwind emissions

* * * as well as to the extent known (at least

qualitatively), the relative costs of, amounts

of reductions from, and ambient impact of

measures available in the downwind areas.

Id.

Under the second interpretation, EPA

considers all of the factors under both

the significant contribution prong and

the mitigation prong of the first

interpretation, and, once EPA

determines an amount of emissions that

does significantly contribute to

downwind nonattainment, then EPA

would determine that the SIP must

contain provisions adequate to prohibit

that amount of emissions. Id. at 60325–

26.

(b) Today’s Action. The EPA has

determined that the second

interpretation should be used; that is,

that the determination of significant

contribution includes both air quality

factors relating to amounts of upwind

emissions and their ambient impact

downwind, as well as cost factors

relating to the costs of the upwind

emissions reductions. Once an amount

of emissions is identified in an upwind

State that contributes significantly to a

nonattainment problem downwind, or

interferes with maintenance downwind,

the SIP must include provisions to

eliminate that amount of emissions.

To reiterate, section 110(a)(2)(D)(i)(I)

provides that the SIP must ‘‘prohibit[]’’

sources from ‘‘emitting any air pollutant

in amounts which will contribute

significantly to nonattainment in, or

interfere with maintenance by, any

other State.’’ The term ‘‘prohibit’’ is

defined as ‘‘to forbid by authority’’ or

‘‘prevent,’’ or ‘‘preclude.’’ ‘‘The

American Heritage Dictionary of the

English Language’’ (3d ed. 1992, 1448).

The EPA believes that the term

‘‘prohibit’’ means that SIPs must

eliminate those amounts of emissions

determined to contribute significantly to

nonattainment or interfere with

maintenance downwind. Moreover, EPA

believes that whether emissions

‘‘contribute significantly’’ depends on a

multifactor test, as described below.

Thus, section 110(a)(2)(D)(i)(I) does not

require the elimination of all upwind

source emissions that impact downwind

air quality problems, but only those

amounts of emissions that, based on a

multi-factor test, significantly contribute

to downwind air quality problems.

d. Multi-factor Test for Determining

Significant Contribution. In the NPR,

EPA proposed a multi-factor test for

determining whether emissions from an

upwind State contribute significantly to

a nonattainment or maintenance

problem downwind. The EPA received

numerous comments on the factors.

Based on the comments and EPA’s

further analysis, EPA, in today’s action,

is continuing the multi-factor approach,

with some refinements in response to

comments, with respect to the factors

EPA considered and the manner in

which EPA considered them.

In determining whether emissions

from upwind States affected by today’s

action contribute significantly to

downwind nonattainment or

maintenance problems, EPA specifically

considered the following factors with

respect to each such upwind State.

These factors were the primary

components in EPA’s consideration.

fl The overall nature of the ozone

problem (i.e., ‘‘collective contribution’’)

fl The extent of the downwind

nonattainment problems to which the

upwind State’s emissions are linked,

including the ambient impact of

controls required under the CAA or

otherwise implemented in the

downwind areas

fl The ambient impact of the

emissions from the upwind State’s

sources on the downwind

nonattainment problems

fl The availability of highly cost

effective control measures for upwind

emissions.

The first three of these factors are

related to air quality; the fourth is

related to costs.

In addition, EPA generally reviewed

several other considerations before

concluding that upwind emissions

contribute significantly to downwind

nonattainment. The EPA did not

consider it necessary, or did not have

adequate information, to apply each of

these factors with specificity with

respect to each upwind State’s

emissions. In addition, in some

instances, EPA did not have quantitative

information to assess certain of these

factors, and instead relied on qualitative

information. These considerations were

secondary aspects of EPA’s analysis.

They include:

fl The consistency of the regional

reductions with the attainment needs of

the downwind areas with

nonattainment problems

fl The overall fairness of the control

regimes required of the downwind and

upwind areas, including the extent of

the controls required or implemented by

the downwind and upwind areas

fl General cost considerations,

including the relative cost-effectiveness

of additional downwind controls

compared to upwind controls

All of these factors and considerations

are described in the following sections.

e. Air Quality Factors. As noted

above, EPA specifically considered

three air quality factors with respect to

each upwind State, which factors, in

conjunction with the cost factor

discussed in the next section, were the

primary components in EPA’s

consideration:

fl The overall nature of the ozone

problem (i.e., ‘‘collective contribution’’)

fl The extent of the downwind

nonattainment problems to which the

upwind State’s emissions are linked,
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57377

26The presence of residual nonattainment in

major urban areas after their implementation of

specifically required CAA controls supports the

regional reductions required under today’s action.

Those regional reductions allow the major urban

areas to progress towards attainment under the 8-

hour NAAQS, and, at the same time, significantly

ameliorate the nonattainment problems under the 8-

hour NAAQS for numerous other areas. In fact, EPA

projections indicate that numerous areas with

nonattainment problems will achieve attainment of

the 8-hour NAAQS as a result of the regional

reductions.

including the ambient impact of

controls required under the CAA or

otherwise implemented in the

downwind areas

fl The ambient impact of the

emissions from the upwind State’s

sources on the downwind

nonattainment problems

(1) Collective Contribution. As

indicated elsewhere, ozone generally

results from the collective contribution

of emissions from numerous sources

over a large geographic area. For

example, for urban nonattainment areas

under the 1-hour NAAQS, the

downwind sources, comprise numerous

stationary sources as well as mobile onroad sources, mobile off-road sources,

and consumer and commercial

products. Further, additional

contributions are made by numerous

upwind States, both adjacent to and

further away from the nonattainment

area itself. The fact that virtually every

nonattainment problem is caused by

numerous sources over a wide

geographic area is a factor suggesting

that the solution to the problem is the

implementation over a wide area of

controls on many sources, each of

which may have a small or

unmeasureable ambient impact by itself.

(2) Extent of Downwind

Nonattainment Problems, Including

Ambient Impact of Required Controls.

In determining whether a downwind

area has a nonattainment problem under

the 1-hour standard to which an upwind

area may be determined to be a

significant contributor, EPA determined

whether the downwind area currently

has a nonattainment problem, and

whether that area area would continue

to have a nonattainment problem as of

the year 2007 assuming that in that area,

all controls specifically required under

the CAA were implemented, and all

required or otherwise expected Federal

measures were implemented. If,

following implementation of such

required CAA controls and Federal

measures, the downwind area would

remain in nonattainment, then EPA

considered that area as having a

nonattainment problem to which

upwind areas may be determined to be

significant contributors.

Thus, this analytical approach

assumes that downwind areas

implement all required controls and

receive the benefit of reductions from

Federal measures, and yet have a

residual nonattainment problem (prior

to the implementation of the regional

reductions required by today’s action).

The fact that a nonattainment problem

persists, notwithstanding fulfillment of

CAA requirements by the downwind

sources, is a factor suggesting that it is

reasonable for the upwind sources to be

part of the solution to the ongoing

nonattainment problem.

The EPA undertook a comparable

analysis with respect to the 8-hour

NAAQS. That is, the major urban areas

in the northeast, midwest, and south

that are violating the 8-hour NAAQS are

designated nonattainment under the 1-

hour NAAQS as well. After these areas

are designated nonattainment under the

8-hour NAAQS, they will become

subject to the control requirements of

section 172(c). However, for these areas,

the section 172(c) requirements do not,

by their terms, impose any specific

controls other than what these areas

have already implemented to fulfill the

requirements under section 182

attendant to their designation and

classification under the 1-hour NAAQS.

Accordingly, the same air quality

modeling analyses that shows residual

nonattainment for at least one of the

urban areas linked to each upwind State

under the 1-hour standard shows

residual nonattainment for those areas

under the 8-hour NAAQS. Indeed,

modeling analyses relied on for today’s

action indicate residual nonattainment

for the major urban areas even after the

implementation of regional reductions

comparable to those required today.26

(3) Ambient Impact of Emissions from

the Upwind Sources. In today’s action,

EPA examined the impact of numerous

upwind States on numerous downwind

areas with nonattainment problems.

Under the 1-hour NAAQS, EPA

conducted various air quality modeling

analyses that examined the impact of

emissions from sources in each upwind

State on ozone levels in downwind

nonattainment areas, in light of the

impact of emissions from sources in

other upwind States on the downwind

area’s nonattainment problem. The EPA

assessed the frequency and magnitude

of each upwind State’s contribution to

downwind nonattainment problems.

Some of the modeling analyses also

permitted determining the magnitude of

the average contribution and the peak

contribution from each upwind State, as

well as the percentage of each upwind

State’s contribution to the downwind

nonattainment problem.

The EPA determined that for each

upwind State affected by today’s action,

its contribution to a downwind

nonattainment problem, in conjunction

with the contribution from other

upwind States, comprised a relatively

large percentage of the nonattainment

problem. The EPA further determined

that, in this context, the impacts from

each affected upwind State’s NOX

emissions are sufficiently large and/or

frequent so that the amounts of that

State’s emissions should be considered

to be significant contributions,

depending on the cost factor and other

relevant considerations. For most

upwind States, EPA conducted two

types of modeling—UAM–V and

CAMx—that isolated the impact of

emissions from the upwind State alone

on downwind nonattainment.

The EPA also conducted much the

same analysis to determine the impact

of emissions from each upwind State on

ozone levels in downwind States under

the 8-hour NAAQS. Because

nonattainment problems under the 8-

hour NAAQS are widespread, and

because EPA has not designated

individual nonattainment areas, EPA

focused this part of its inquiry on the

upwind State’s impact on the entire

downwind State.

The EPA’s analysis under both the 1-

hour and 8-hour NAAQS led EPA to

conclude that, in light of both the

collective contribution nature of the

ozone problem, and the fact that

downwind areas continue to suffer a

nonattainment problem even after

implementation of all required CAA

measures and Federal measures,

emissions from each of the affected

upwind States have a sufficiently large

and/or frequent ambient impact such

that those emissions contribute

significantly to nonattainment

downwind, depending on the

availability of highly cost-effective

measures and on other considerations

discussed below.

f. Determination of Highly Costeffective Reductions and of Budgets.

After determining the degree to which

NOX emissions, as a whole from the

particular upwind States, contribute to

downwind nonattainment or

maintenance problems, EPA then

determined whether any amounts of the

NOX emissions may be eliminated

through controls that, on a cost-per-ton

basis, may be considered to be highly

cost effective. By examining the cost

effectiveness of recently promulgated or

proposed NOX controls, EPA

determined that an average of

approximately $2,000 per ton removed
57378 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

27As indicated in the NPR, EPA considers that

measures may be reasonable in light of their

reduction of VOC and NOX emissions, even though

their cost-effectiveness in terms of cost per NOX

emissions removed is relatively high (62 FR 60346–

48).

is highly cost effective. The EPA then

determined a set of controls on NOX

sources that would cost no more than an

average of $2,000 per ton reduced.

Specifically, EPA determined that one

set of these controls would include a

cap-and-trade program for (i) electricity

generating boilers and turbines larger

than 25 Mwe (‘‘large EGUs’’), and (ii)

large non-electricity generating

industrial boilers and turbines (‘‘large

non-EGU boilers and turbines’’). The

application of an emission rate of 0.15

lb/mmBtu and 1995–1996 utilization for

EGUs and 60 percent for large non-EGUs

to the emissions projected to occur in

2007 including growth and CAA

measures, led to the determination of

the amounts to be reduced. The

remaining amount is a State’s budget.

The EPA further determined that

additional highly cost-effective controls

are also available for cement

manufacturing sources and internal

combustion engines. On the basis of

reasonable assumptions concerning

growth to the year 2007, EPA then

determined the amounts of emissions

from these source categories that would

be eliminated with those controls.

The EPA further determined that

there were no other controls on other

NOX sources that qualify as highly cost

effective (although several controls are

reasonably cost-effective).

On the basis of the determinations

just described for the various source

categories, EPA determined an amount

of NOX emissions that may be

eliminated through these highly costeffective measures. Because EPA had

also determined that the NOX emissions

from the affected upwind States have a

large and/or frequent impact on

downwind nonattainment or

maintenance problems, EPA concludes

that the amount of NOX emissions from

those States that can be eliminated

through application of highly costeffective control measures contributes

significantly to nonattainment or

maintenance problems downwind.

Under section 110(a)(2)(D)(i)(I), the

SIP must include ‘‘adequate provisions

prohibiting’’ sources from emitting these

‘‘amounts.’’ Because no highly costeffective controls are available to

eliminate the remaining amounts of

NOX emissions, EPA concludes that

those emissions do not contribute

significantly to downwind

nonattainment or maintenance

problems. As indicated below and in

Section III, there are cost-effective

alternatives available to States that

choose not to adopt all of the highly

cost-effective measures on which EPA

based its selection of the significant

amounts of NOX emissions.

To implement EPA’s determinations,

each affected upwind State is required

to submit for EPA approval SIP controls

projected to be sufficient, by the year

2007, to eliminate the amount of NOX

emissions in the State that EPA

determined contributes significantly to

nonattainment. The EPA determined

this amount of reductions, for each

affected upwind State, as follows: EPA

first determined the amount of NOX

emissions in that State by the year 2007,

based on assumptions concerning both

growth and emissions controls that are

required under the CAA or that will be

implemented due to Federal actions (the

‘‘2007 base case’’). Second, EPA applied

the control measures identified as

highly cost effective to the 2007 base

case amount for the appropriate source

categories. The amount of NOX

emissions remaining in the State after

application of controls to the affected

source categories constitutes the 2007

budget. The difference between the 2007

base case and the 2007 budget is the

amount of NOX emissions in that State

by the year 2007 that EPA has

determined to contribute significantly to

nonattainment and that, therefore, the

SIPs must prohibit.

The upwind State’s SIP revision due

in response to today’s action must

provide controls that, on the basis of the

same assumptions (including

concerning growth) made by EPA in

determining the budget, would limit

NOX emissions in the year 2007 to no

more than the 2007 budget. The State

has full discretion in selecting the

controls, so that it may choose any set

of controls that would assure

achievement of the budget.

As EPA stated in the NPR:

States are not constrained to adopt

measures that mirror the measures EPA used

in calculating the budgets. In fact, EPA

believes that many control measures not on

the list relied upon to develop EPA’s

proposed budgets are reasonable—especially

those, like enhanced vehicle inspection and

maintenance programs, that yield both NOX

and VOC emissions reductions.[ 27] Thus, one

State may choose to primarily achieve

emissions reductions from stationary sources

while another State may focus emission

reductions from the mobile source sector.

(62 FR 60328).

The EPA believes that its overall

approach derives further support from

the mandate in section 110(a)(2)(D) that

each SIP include provisions prohibiting

‘‘any source or other type of emissions

activity within the State from emitting

any air pollutant in amounts’ that

adversely affect downwind areas. The

phrase ‘‘any source or other type of

emissions activity’’ may be interpreted

to require that the SIP regulate all

sources of emissions to assure that the

total amount of emissions generated

within the State does not adversely

affect downwind areas. By its terms, the

phrase covers all emitters of any kind

because every emitter—stationary,

mobile, or area—may be considered a

‘‘source or other type of emissions

activity.’’ This interpretation is

consistent with the legislative history of

the phrase. Prior to the CAA

Amendments of 1990, the predecessor

to section 110(a)(2)(D), which was

section 110(a)(2)(E), referred to ‘‘any

stationary source within the State.’’ In

the 1990 Amendments, Congress revised

the phrase to read as it currently does.

A Committee Report explained, ‘‘Where

prohibitions in existing section

110(a)(2)(E) apply only to emissions

from a single source, the amendment

includes ‘‘any other type of emissions

activity,’’ which makes the provision

effective in prohibiting emissions from,

for example, multiple sources, mobile

sources, and area sources.’’ V Leg. Hist.

8361, S. Rep. No. 228, 101st Cong., 1st

Sess. 21 (1989).

For reasons explained below, if an

upwind State chooses to achieve all or

a portion of the required reductions

from large EGUs or large non-EGU

boilers and turbines, then the SIP must

include a mass emissions limitation for

those sources computed with reference

to certain growth assumptions and the

emission rate limits chosen by the State.

The EPA recommends that this mass

limitation, or cap, be accompanied by a

trading program. Any such cap-andtrade program must be established by

May 1, 2003. If the State chooses to

achieve all or a portion of the required

reductions from other sources, then the

State must implement controls, by the

year 2003, on those other sources that

are projected to achieve the required

level of reductions, based on certain

assumptions (including growth), in the

year 2007. The controls on these other

sources may be rate-based, and no

emissions cap on them is required. By

the year 2007, any applicable mass

emissions limitation for large EGUs or

large non-EGU boilers and turbines

must continue to be met, and any

applicable controls on other sources

must continue to be implemented. The

amount of the 2007 overall budget is

used to compute the level of controls

that would result in the appropriate

amount of emissions reductions, given

assumptions concerning, for example,
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57379

growth. To this extent, the 2007 overall

budget is an important accounting tool.

However, the State is not required to

demonstrate that it has limited its total

NOX emissions to the budget amounts.

Thus, the overall budget amount is not

an independently enforceable

requirement.

g. Other Considerations in

Determination of Significant

Contribution. The EPA reviewed several

other considerations in support of its

determination that the specified

amounts of emissions from the affected

upwind States contribute significantly

to nonattainment downwind.

(1) Consistency of Regional

Reductions with Downwind Attainment

Needs. The EPA conducted modeling

analyses of emission reductions of

virtually the same magnitude as the

regional reductions required under

today’s action. Although the impact on

any downwind ozone problem of each

upwind State’s emissions reductions

alone may be relatively small, the

impact of those reductions, when

combined with the reductions from the

other States, is substantial. Based on

this modeling, EPA determined that the

regional reductions allow downwind

nonattainment areas under the 1-hour

NAAQS to make appreciable progress

towards attainment. The EPA further

determined that under the 8-hour

NAAQS, many areas with

nonattainment problems are expected to

reach attainment based solely on the

regional reductions, and that other

(primarily urban) areas would benefit

from the regional reductions but are

expected to experience residual

nonattainment. EPA further determined

that none of the upwind States affected

by today’s action are affected by

‘‘overkill,’’ that is, required reductions

that are more than necessary to

ameliorate downwind nonattainment in

every downwind area affected by that

upwind State.

(2) Fairness. The EPA also considered

the overall fairness of the control

regimes required of the downwind and

upwind areas, including the extent of

the controls required or implemented by

the downwind and upwind areas. Most

broadly, EPA believes that overall

notions of fairness suggest that upwind

sources which contribute significant

amounts to the nonattainment problem

should implement cost-effective

reductions. When upwind emitters

exacerbate their downwind neighbors’

ozone nonattainment problems, and

thereby visit upon their downwind

neighbors additional health risks and

potential clean-up costs, EPA considers

it fair to require the upwind neighbors

to reduce at least the portion of their

emissions for which highly costeffective controls are available.

In addition, EPA recognizes that in

many instances, areas designated as

nonattainment under the 1-hour

NAAQS have incurred ozone control

costs since the early 1970s. Moreover,

virtually all components of their NOx

and VOC inventories are subject to SIPrequired or Federal controls designed to

reduce ozone. Furthermore, these areas

have complied with almost all of the

specific control requirements under the

CAA, and generally are moving towards

compliance with their remaining

obligations. The CAA’s sanctions and

FIP provisions provide assurance that

these remaining controls will be

implemented. By comparison, many

upwind States in the midwest and south

have had fewer nonattainment problems

and have incurred fewer control

obligations.

(3) General Cost Considerations. The

EPA also considered the fact that in

general, areas that currently have, or

that in the past have had, nonattainment

problems under the 1-hour NAAQS, or

that are in the Northeast Ozone

Transport Region (OTR), have already

incurred ozone control costs. The

controls already implemented in these

areas tend to be among the less

expensive of available controls. As

described in more detail below, EPA has

determined that, in general, the next set

of controls identified as available in the

downwind nonattainment areas under

the 1-hour NAAQS would cost

approximately $4,300 per ton removed.

By comparison, EPA has determined

that the cost of the regional reductions

required today would approximate

$1,500 per ton removed. Thus, it

appears that the upwind reductions

required by today’s action are more costeffective per ton removed than

reductions in the downwind

nonattainment areas. Moreover, under

the 1-hour NAAQS, the reductions

required from each upwind State, in

conjunction with reductions from other

upwind States, result in ambient

improvement in at least several

downwind areas with nonattainment

problems.

The EPA did not have available, and

was not presented with, meaningful

quantitative information indicating the

cost-effectiveness of the regional

reductions required today in light of

their ambient impact downwind (e.g.,

the cost of emissions reductions per ppb

improvement in ambient ozone levels in

a downwind nonattainment area). This

lack of information limited the extent to

which EPA could rely on this

consideration in making its

determinations.

The various considerations just

discussed point in the same direction as

the other factors described above

concerning air quality and costs. These

factors and considerations lead EPA to

conclude that the amounts of each

upwind State’s emissions that may be

eliminated through highly cost-effective

measures contribute significantly to

nonattainment or maintenance problems

downwind.

h. Interfere with Maintenance. Once a

nonattainment area has attained the

NAAQS, it is required to maintain that

standard (e.g., sections 107(d)(3)(E)(iv),

110(a)(1)). Section 110(a)(2)(D)(i)(I) also

requires that SIPs contain adequate

provisions prohibiting amounts of

emissions that ‘‘interfere with

maintenance by * * * any [downwind]

State.’’ The EPA explained and applied

this requirement in the NPR as follows:

This [interfere-with-maintenance]

requirement * * * does not, by its terms,

incorporate the qualifier of ‘‘significantly.’’

Even so, EPA believes that for present

purposes, the term ‘‘interfere’’ should be

interpreted much the same as the term

‘‘contribute significantly,’’ that is, through

the same weight-of-evidence approach.

With respect to the 1-hour NAAQS, the

‘‘interfere-with-maintenance’’ prong appears

to be inapplicable. The EPA has determined

that the 1-hour NAAQS will no longer apply

to an area after EPA has determined that the

area has attained that NAAQS. Under these

circumstances, emissions from an upwind

area cannot interfere with maintenance of the

1-hour NAAQS.

With respect to the 8-hour NAAQS, the

‘‘interfere-with-maintenance’’ prong remains

important. After an area has reached

attainment of the 8-hour NAAQS, that area is

obligated to maintain that NAAQS. (See

sections 110(a)(1) and 175A.) Emissions from

sources in an upwind area may interfere with

that maintenance.

The EPA proposes to apply much the same

approach in analyzing the first component of

the ‘‘interfere-with-maintenance’’ issue,

which is identifying the downwind areas

whose maintenance of the NAAQS may

suffer interference due to upwind emissions.

The EPA has analyzed the ‘‘interfere-withmaintenance’’ issue for the 8-hour NAAQS

by examining areas whose current air quality

is monitored as attaining the 8-hour NAAQS

[or which have no current air quality

monitoring], but for which air quality

modeling shows nonattainment in the year

2007. This result is projected to occur,

notwithstanding the imposition of certain

controls required under the CAA, because of

projected increases in emissions due to

growth in emissions generating activity.

Under these circumstances, emissions from

upwind areas may interfere with the

downwind area’s ability to attain.

Ascertaining the impact on the downwind

area’s air quality of the upwind area’s

emissions aids in determining whether the

upwind emissions interfere with

maintenance
57380 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

28Reductions specifically required by the CAA

include, for example, the 3 percent-per-year ROP

reductions required of ozone nonattainment areas

classified as serious or higher, under section

182(c)(2)(B).

29–30 If downwind areas fail to meet their planning

obligations, they are subject to sanctions (See

Section VI, below. As EPA noted in the NPR, 62 FR

60322–23, in some instances, States in the

Northeast failed to submit all of their required SIP

revisions or other commitments under Phase 1 of

the March 2, 1995 Memorandum and as a result,

EPA initiated the sanctions process by starting

sanctions clocks. In general, those States have since

made the required Phase 1 submissions, and EPA

terminated the sanctions process by stopping the

clocks.

(62 FR 60326).

In today’s action, EPA is taking the

same positions with respect to the

interfere-with-maintenance test as

described in the NPR. Because EPA

generally interprets the ‘‘interfere-withmaintenance’’ test the same as the

‘‘contributes-significantly-tononattainment’’ test, for purposes of

convenience, in this final rule, EPA

sometimes refers to ‘‘contributessignificantly-to-nonattainment’’ to refer

to both tests.

i. Dates. In today’s action, EPA is

determining that SIP submissions

required under this rulemaking must be

submitted by September 30, 1999 (see

Section VI.A.1, Schedule for SIP

Revision).

Further, in today’s action, EPA is

requiring that SIP controls required

today must be implemented by no later

than May 1, 2003, and they must

achieve reductions computed with

reference to an overall budget amount

determined as of September 30, 2007

(see Section V, NOX Control

Implementation and Budget

Achievement Dates).

j. Downwind Areas’ Control

Obligations. Commenters have argued

that under the CAA, downwind States

must implement additional controls

before EPA may require controls in

upwind States. Commenters base this

argument in part on the provisions of

CAA section 107(a), which provides,

Each State shall have the primary

responsibility for assuring air quality within

the entire geographic area comprising such

State by submitting an implementation plan

for such State which will specify the manner

in which [NAAQS] will be achieved and

maintained within each air quality control

region in such State.

Commenters further note that

downwind States must implement

additional reductions (beyond those

specifically required by the CAA 28) as

needed to attain, under section

182(b)(1)(A)(i) and 182(c)(2)(A). The

commenters add that section 179(d)(2)

is a generally applicable provision that

limits the stringency of required

controls to what is feasible. The

commenters read these provisions

together to conclude that downwind

States must first implement all feasible

control measures in an effort to reach

attainment, and only after EPA

determines that such States have done

so but have not reached attainment may

EPA require upwind contributors to

implement controls. The commenters

further observe that some of the

downwind States in the Northeast have

not implemented all feasible SIP

measures.

The EPA disagrees with this legal

analysis. The provision in section 107(a)

that accords to States the primary

responsibility for the air quality of their

air basins, in essence provides the

underlying rationale for the requirement

of States to submit SIP revisions that

meet CAA requirements. This phrase

clarifies that the requirement of assuring

attainment does not fall, in the first

instance, on EPA. This provision does

not have implications for apportioning

responsibility between the downwind

State and upwind States for

contributions from upwind States.

Downwind States would still carry the

primary responsibility of assuring clean

air even after the upwind contributors

have revised their SIPs to meet the

requirements of section 110(a)(2)(D).

Furthermore, EPA disagrees that

section 179(d)(2) has any application to

today’s rulemaking. That provision in

essence provides a general rule that if a

nonattainment area fails to attain by its

attainment date, EPA may require the

State to implement reasonable controls

that can be ‘‘feasibly implemented.’’

This requirement is not relevant to

today’s rulemaking, which addresses the

requirements under section

110(a)(2)(D)(i)(I) that SIPs include

provisions eliminating amounts of

emissions from their sources that

contribute significantly to downwind

nonattainment.

In addition, the requirement of

downwind States to implement

reductions beyond minimum CAA

requirements if needed for attainment

does not place the burden of

implementing those reductions, in the

first instance, on the downwind States.

This requirement should be read to go

hand-in-hand with the section

110(a)(2)(D) requirement that upwind

States include SIP provisions that

prohibit their sources from emitting air

pollutants in amounts that

‘‘significantly contribute’’ to downwind

nonattainment. In today’s action, EPA is

promulgating criteria for interpreting

section 110(a)(2)(D) to take into account

downwind attainment needs.

As a practical matter, EPA has

reviewed the status of Northeast States’

efforts to comply with the requirements

of the 1990 CAA Amendments and has

found that these States have complied

with the vast majority of the SIP

submission requirements. Even so, EPA

is well aware that some of the States

have not made certain required

submissions. 29–30 However, EPA sees no

basis in section 110(a)(2)(D) to mandate

that downwind areas complete their SIP

planning and implementation before

upwind areas are required to begin that

process. Upwind areas have been

subject to the requirements of section

110(a)(2)(D)—in some form—since the

predecessor to this provision was added

in the 1977 CAA Amendments. The

EPA has determined, through air quality

modeling, that even after the downwind

States fulfill their prescribed CAA

requirements, they will have areas

expected to remain in nonattainment.

Under these circumstances, the

downwind areas continue to constitute

areas with air quality in

‘‘nonattainment’’ under section

110(a)(2)(D). As a result, upwind areas

with emissions in amounts that

‘‘significantly contribute’’ to the

nonattainment air quality downwind are

subject to control requirements whether

or not the downwind areas they affect

have met all of their planning

obligations.

k. Section 110(a)(2)(D) Caselaw. In the

NPR, EPA noted that prior to the CAA

Amendments of 1990, EPA had issued

several rulemakings under section

110(a)(2)(E), the predecessor to section

110(a)(2)(D), and section 126 that

addressed the issue of significant

contribution in the context of pollutant

transport. In those rulemakings, EPA

generally applied a multi-factor test to

determine whether the emissions from

the sources in question constituted a

signficant contribution to downwind

jurisdictions. In each instance, EPA

concluded that the emissions at issue

from the upwind sources were not

demonstrated to impact downwind air

quality in a manner that would

constitute significant contribution.

Several of these determinations resulted

in judicial challenges, but in each

instance the courts upheld the Agency’s

determination of no significant

contribution. The EPA indicated in the

NPR that the prior rulemakings and the

related court holdings, provide limited

precedents for today’s action. The EPA

noted that these decisions have limited

relevance because they involved

different facts and circumstances,

including different pollutants, different
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57381

31Comprehensive Air Quality Model with

Extensions.

32The UAM–V and CAMX models are described

in the Air Quality Modeling TSD.

upwind sources, and different

downwind effects.

Several commenters asserted that

these prior rulemakings and cases are

relevant to today’s action, and compel

EPA to conclude that the emissions

from the upwind States affected by

today’s action do not contribute

significantly to downwind

nonattainment or maintenance

problems. The EPA disagrees that these

earlier determinations are controlling

and that these earlier determinations are

inconsistent with today’s action. The

EPA responds to these comments in

detail in the Response to Comment

document.

B. Alternative Interpretation of Section

110(a)(2)(D)

As discussed above, in the NPR EPA

advanced an alternative interpretation

of section 110(a)(2)(D) (62 FR 60327).

Under this alternative interpretation,

EPA would determine the level of

emissions that significantly contribute

to nonattainment downwind based on

factors relating to the entire amount of

upwind emissions from a particular

upwind State and their ambient impact

downwind. The EPA would then

determine what emissions reductions

must be required to adequately mitigate

that significant contribution based on

factors relating to cost effectiveness of

reductions and attainment needs

downwind.

The EPA continues to believe that this

alternative interpretation remains a

permissible interpretation of the statute

for the reasons described in the NPR (62

FR 60327). In any event, it should be

noted that for purposes of today’s

action, EPA finds no practical difference

between the requirements that would

result from the interpretation of section

110(a)(2)(D) adopted today and those

that would result from the alternative

interpretation described in the NPR.

That is, even under the alternative

interpretation, today’s rulemaking

would contain the same findings and

require the same SIP revisions as under

the interpretation adopted today (62 FR

60327).

C. Weight-of-Evidence Determination of

Covered States

As discussed above, EPA applied a

multi-factor approach to identify the

amounts of NOX emissions that

contribute significantly to

nonattainment. The EPA evaluated three

air quality factors for each upwind

jurisdiction (hereafter referred to as

‘‘States’’ or ‘‘upwind States’’) to

determine whether each has emissions

whose contributions to downwind

nonattainment problems are large and/

or frequent enough to be of concern.

Further, for those States whose

emissions are large and/or frequent

enough to be of concern, EPA applied

highly cost-effective controls to

determine the amount of NOx in upwind

States which significantly contributes to

nonattainment in, or interferes with

maintenance by, a downwind State. The

EPA also generally reviewed several

other considerations before drawing

final conclusions. Even though the

actual finding of significant contribution

applies only to the portion of a State’s

emissions for which EPA has identified

highly cost-effective controls, for ease of

discussion, the term ‘‘significant’’ (or

like term) is used in the discussion in

this section to characterize the

emissions of each upwind State that

make a large and/or frequent

contribution to nonattainment in

downwind States sufficient to warrant

eliminating a portion of its emissions

equivalent to what can be removed

through those controls.

The purpose of this section is to

describe the technical analyses

performed by EPA to (a) quantify the air

quality contributions from emissions in

each upwind State on both 1-hour and

8-hour nonattainment, as well as 8-hour

maintenance, in each downwind State,

and (b) determine whether these

contributions are significant.

In the proposed weight-of-evidence

approach, EPA specifically applied

several factors to each upwind State, as

discussed in Section II.A.3.c, Definition

of Significant Contribution. These

factors include:

• The overall nature of ozone

problem (i.e., ‘‘collective contribution’’);

• The extent of the downwind

nonattainment problems to which the

upwind State’s emissions are linked,

including the ambient impact of

controls required under the CAA or

otherwise implemented in the

downwind areas; and

• The ambient impact of the

emissions from the upwind State’s

sources on the downwind

nonattainment problems.

As part of the analysis of these factors,

EPA considered the findings from

OTAG’s technical analyses, as well as

the findings from a number of other

studies performed by OTAG

participants independent of OTAG. The

major findings from these analyses are

described below. This is followed by an

overview of the approach used by EPA

in the proposal for considering the

above factors to identify States that

make a significant contribution to

downwind nonattainment. The

comments and EPA’s response to

comments on EPA’s weight-of-evidence

proposal are then discussed. Following

that discussion, the results of additional

State-by-State UAM–V modeling and

State-by-State CAMX 31 source

apportionment modeling performed by

EPA in response to comments are

summarized.32 The EPA’s analysis of the

modeling results in terms of the

significance of the contributions of

upwind States to downwind

nonattainment is presented in Section

II.C.4, Confirmation of States Making a

Significant Contribution to Downwind

Nonattainment.

1. Major Findings From OTAG-Related

Technical Analyses

The major findings from the air

quality and modeling analyses by OTAG

and individual OTAG participants that

are most relevant to today’s rulemaking

are as follows:

• several different scales of transport

(i.e., intercity, intrastate, interstate, and

inter-regional) are important to the

formation of high ozone in many areas

of the East;

• emissions reductions in a given

multistate region/subregion have the

most effect on ozone in that same

region/subregion;

• emissions reductions in a given

multistate region/subregion also affect

ozone in downwind multistate regions/

subregions;

• downwind ozone benefits decrease

with distance from the source region/

subregion (i.e., farther away, less effect);

• downwind ozone benefits increase

as the size of the upwind area being

controlled increases, indicating that

there is a cumulative benefit to

extending controls over a larger area;

• downwind ozone benefits increase

as upwind emissions reductions

increase (the larger the upwind

reduction, the greater the downwind

benefits);

• a regional strategy focusing on NOX

reductions across a broad portion of the

region will help mitigate the ozone

problem in many areas of the East;

• both elevated and low-level NOX

reductions decrease ozone

concentrations regionwide;

• there are ozone benefits across the

range of controls considered by OTAG;

the greatest benefits occur with the most

emissions reductions; there was no

‘‘bright line’’ beyond which the benefits

of emissions reductions diminish

significantly;

• even with the large ozone

reductions that would occur if the most
57382 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

stringent controls considered by OTAG

were implemented, there may still

remain high concentrations in some

portions of the OTAG region; and a

regional NOX emissions reduction

strategy coupled with local NOX and/or

VOC reductions may be needed to

enable attainment and maintenance of

the NAAQS in this region.

The above findings provide technical

evidence that transport within portions

of the OTAG region results in large

contributions from upwind States to

ozone in downwind areas, and that a

regionwide approach to reduce NOX

emissions is an effective way to address

these interstate contributions.

2. Summary of Notice of Proposed

Rulemaking Weight-of-Evidence

Approach

The EPA relied on OTAG data to

develop the information necessary to

evaluate the weight-of-evidence factors

identified above. These data include

emissions (tons) and emission density

(tons per square mile), air quality

analyses, trajectory, wind vector, and

‘‘ozone cloud’’ analyses, and

subregional zero-out modeling. In brief,

EPA’s proposed approach was as

follows:

• the OTAG transport distance scale

was applied to identify, based on the

meteorological potential for transport,

which States may contribute to ozone in

downwind States;

• the results of the OTAG subregional

modeling runs (described below) were

used to quantify the extent to which

each subregion contributes to

downwind nonattainment for the 1-hour

and/or 8-hour NAAQS;

• the OTAG 2007 Base Case NOX

emissions and emissions density were

used to identify States which emit large

amounts of NOX and/or have a high

density of NOX emissions compared to

other States in the OTAG region and,

therefore, have NOX emissions which

may be great enough to contribute to

downwind nonattainment; and the

OTAG 2007 Base Case NOX emissions

were also used to translate the findings

from the subregional modeling to a

State-by-State basis.

a. Quantification of Contributions. As

part of OTAG’s assessment of transport,

a series of model runs were performed

to examine the impacts of emissions

from each of 12 multistate subregions on

ozone in downwind areas. The locations

of these subregions are shown in Figure

II–1.

In each subregional model run, all

manmade emissions were removed from

one upwind subregion and the model

was run for the OTAG July 1988 and

1995 episodes. The ‘‘parts per billion

(ppb)’’ differences in ozone between

each subregional zero-out run compared

to the corresponding 2007 Base Case run

were used to quantify the air quality

impacts of the subregion on

nonattainment downwind.

In the proposed NOX SIP call, EPA

considered areas as ‘‘nonattainment’’ if

air quality monitoring indicates that the

area is currently measuring

nonattainment and if air quality

modeling indicates future

nonattainment, taking into account CAA

control requirements and growth. In this

regard, areas were considered

nonattainment for the 1-hour NAAQS if
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57383

33 Data for 1994–1996 were used because these

were the most recent quality-assured data available

at the time the analysis was performed.

34 In response to comments, EPA has reexamined

the method for relating 8-hour model predictions

during the OTAG episodes to the form of the 8-hour

NAAQS. This is discussed further in Section

II.C.2.c, Comments and Responses on the Proposed

Weight of Evidence Approach to Significant

Contribution.

they had 1994–1996 33 monitoring data

indicating measured 1-hour violations

and 2007 Base Case 1-hour predictions

>=125 ppb. Areas were considered to be

nonattainment for the 8-hour NAAQS if

they had 1994–1996 monitoring data

indicating measured 8-hour violations

and 2007 Base Case 8-hour predictions

>=85 ppb. The inconsistency between

the form of the 8-hour NAAQS, which

considers 3 years of data for

determining the average of the fourthhighest 8-hour daily maximum

concentration at a monitor, and the

limited predictions available from the

OTAG episodes introduced a

complication to the analysis of 8-hour

contributions. It was not possible to use

the model predictions in a way that

explicitly matched the form of the 8-

hour NAAQS. Instead, an analysis of

seasonal and episodic ozone

measurements was performed in an

attempt to link 8-hour measured

concentrations during the OTAG

episodes to the form of the 8-hour

NAAQS, as closely as possible. The

results of that analysis indicated that the

3-episode average of the second highest

8-hour ozone concentrations measured

during the OTAG 1991, 1993, and 1995

episodes corresponded best, overall, to

the 3-year average of the fourth highest

8-hour daily ambient data. However,

since OTAG subregional modeling was

only available for the 1988 and 1995

episodes, EPA used the concentrations

during these two episodes in calculating

average second high 8-hour

concentrations.34

b. Evaluation of 1-Hour and 8-Hour

Contributions. In the proposal, EPA

summarized the ‘‘ppb’’ contributions to

downwind nonattainment from each

subregion in terms of both the frequency

and the magnitude of the downwind

impacts over specific concentration

ranges (e.g., 2 to 5 ppb, 5 to 10 ppb, 10

to 15 ppb, etc.). The results indicate

that, in general, large contributions to

downwind nonattainment occur on

numerous occasions. Although the level

of downwind contribution varies from

subregion to subregion, a consistent

pattern is apparent for both 1-hour

nonattainment and 8-hour

nonattainment. Specifically, the results

of the subregional modeling indicate

that emissions from States in subregions

1 through 9 produce large 1-hour and 8-

hour contributions downwind in terms

of the magnitude and frequency,

including geographic extent, of the

downwind impacts. In addition,

nonattainment areas within many States

in the OTAG region receive large and/

or frequent contributions from

emissions in these subregions. The EPA

proposed to find that most of the States

whose emissions are wholly or partially

contained within one or more of these

subregions (i.e., Alabama, Connecticut,

Delaware, Georgia, Illinois, Indiana,

Kentucky, Maryland, Michigan,

Missouri, New Jersey, New York, North

Carolina, Ohio, Pennsylvania, South

Carolina, Tennessee, Virginia, West

Virginia, and Wisconsin, as well as the

District of Columbia) are making a

significant contribution to downwind

nonattainment. In addition to the

ambient impact demonstrated by the

subregional modeling, this proposed

finding was based on a determination

that:

• OTAG strategy modeling and nonOTAG modeling indicate that NOX

emissions reductions across these States

would produce large reductions in 1-

hour and 8-hour ozone concentrations

across broad portions of the region

including 1-hour and 8-hour

nonattainment areas;

• these States are upwind from

nonattainment areas within the 1- to 2-

day distance scale of transport;

• these States form a contiguous area

of manmade emissions covering most of

the core portion of the OTAG region;

• 11 of the States that are wholly

within subregions 1 through 9 have a

relatively high level of NOX emissions

from sources in their States; these States

are ranked in the top 50 percent of all

States in the region in terms of total

NOX emissions and/or have NOX

emissions exceeding 1000 tons per day;

• States wholly within subregions 1

through 9 with lesser emissions have a

relatively high density of NOX

emissions;

• for the seven States that are only

partially contained in one of subregions

1 through 9, the State total NOX

emissions, as well as each State’s

contribution to NOX emissions in the

subregions in which they are located,

indicate that six of the States each have:

NOX emissions that are more than 10

percent of the total NOX emissions in

one of these subregions, NOX emissions

in the top 50 percent among all States,

and/or a majority of its NOX emissions

within one of these subregions.

For the New England States that were

not included in any of the OTAG zeroout subregions, EPA found that two of

these States (i.e., Massachusetts and

Rhode Island) have a high density of

NOX emissions. Also, the trajectory and

wind vector analyses indicated that

these States are immediately upwind of

nonattainment areas in other States.

For the nine States in the OTAG

region which are wholly within

subregions 10, 11, and 12 (i.e., Florida,

Kansas, Louisiana, Minnesota,

Nebraska, North Dakota, Oklahoma,

South Dakota, and Texas), and for

Arkansas, Iowa, and Mississippi, EPA

proposed that emissions from each of

these States should be considered not to

significantly contribute to downwind

nonattainment. These States are further

discussed below in Section II.C.5, States

Not Covered by this Rulemaking.

c. Comments and Responses on

Proposed Weight-of-Evidence Approach

to Significant Contribution. The EPA

received a number of comments on

various elements of the proposed

weight-of-evidence approach. In

addition, EPA received new modeling

and analyses performed by commenters

which address the issue of significant

contribution. The following is a

summary of the major comments

received by EPA and the responses to

these comments. Additional comments

and EPA’s response to these comments

are provided in the Response to

Comment document.

Comment: Some commenters stated

that it was inappropriate to use a

weight-of-evidence approach to

determine the significance of upwind

emissions on downwind nonattainment.

Rather, it was argued that EPA should

use a specific ‘‘bright line’’ criterion.

Other commenters supported the

weight-of-evidence approach.

Response: The magnitude and

frequency of contributions from an

upwind State to downwind

nonattainment depend on the extent of

the nonattainment problem in the

downwind area, the emissions in the

downwind area, the emissions in the

upwind State, the distance between the

upwind State and the downwind area,

and weather conditions (i.e., winds and

temperatures which favor ozone

formation and transport). Because these

factors vary in a complex way across the

OTAG region, it is not possible to

develop a single bright line test for

significance that will be applicable and

appropriate for all potential upwindState-to-downwind-area linkages.

Therefore, EPA believes that it is more

appropriate to use a weight-of-evidence

approach to account for all of these

factors than establishing a bright line

criterion.

Comment: Some commented that EPA

should not use the trajectory, wind

vector, and ‘‘ozone cloud’’ analyses as a
57384 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

basis for determining significant

contribution because these techniques

indicate air movement and do not

account for ozone formation and

depletion due to photochemical

reactions and other processes. Other

commenters argued in favor of using

this information as means of linking

upwind States with downwind

nonattainment.

Response: The EPA agrees that

information from such techniques

should not be used as the sole basis for

finding that certain upwind States

significantly contribute to

nonattainment in specific downwind

States. However, EPA believes that it is

important to consider the ‘‘movement’’

of ozone and/or precursors as part of the

air quality evaluation of contributions

from upwind States. This factor is

incorporated into the air quality models

used by EPA for this rulemaking. The

inclusion of this information, in

conjunction with numerous other air

quality factors in the models, provides

for a more technically robust analysis

than can be provided by the trajectory,

ozone cloud, and wind vector analyses

alone.

Comment: A number of commenters

stated that CAA section 110(a)(2)(D)

requires a State-by-State demonstration

that emissions within an upwind State

make a significant contribution to

nonattainment in another State and

thus, EPA’s proposed approach of using

subregional (i.e., multistate) modeling,

together with each upwind State’s NOX

emissions, to establish these linkages is

legally flawed. These commenters

argued that section 110(a)(2)(D) requires

‘‘each implementation plan submitted

by a State’’ to contain provisions that

prohibit any source or other type of

emissions activity ‘‘within the State’’

from emitting air pollutants in amounts

that contribute significantly to a

downwind nonattainment problem. The

commenters concluded that these

provisions require, as a matter of

technical procedure, that EPA must base

its determination that emissions from a

particular State significantly contribute

to nonattainment downwind on a

technical analysis of that particular

State’s emissions. According to the

commenters, section 110(a)(2)(D) by its

terms, prohibits EPA from making that

technical determination by examining

the impact of emissions from a group of

States on a downwind nonattainment

problem, and then extrapolating from

that information to determine whether

emissions from each State within that

group should be considered to make a

significant contribution.

As a technical matter, these

commenters argue that if emissions from

more than one State are lumped together

in assessing the contribution to a

downwind State, there is no way to

determine the amount of emissions in

each contributing State that must be

reduced. The commenters argue that the

only way to establish specific upwind

State to downwind State linkages is

through air quality modeling on a Stateby-State basis. Further, the commenters

contend that once an area beyond a

particular State’s boundaries is

modeled, there is no way of knowing

how much farther upwind to go in terms

of defining a source area. In order to

address these issues, many commenters

stated that EPA must do State-by-State

zero-out UAM–V modeling and/or Stateby-State source apportionment

modeling using the CAMx model to

determine downwind contributions

from upwind States.

Response: On the legal issue, EPA

disagrees that the above-referenced

provisions of section 110(a)(2)(D), by

their terms, mandate the technical

procedure for EPA to make the

determination of significant

contribution. These provisions simply

indicate that EPA must make that

determination on a SIP-by-SIP basis,

that is, for EPA to issue a SIP call with

respect to a particular State, EPA must

determine that the provisions of that SIP

fail to adequately control emissions

from sources within the State. However,

these provisions do not mandate any

particular technical procedure for

making that determination. As a result,

EPA may employ any technical

procedure that is sufficiently accurate.

As discussed below, EPA believes that

its subregional approach is sufficiently

accurate to justify the SIP call. However,

in response to this and other comments,

EPA did conduct State-by-State

modeling. The results of this modeling,

as discussed below, confirm the results

of the subregional modeling.

On the technical issue, EPA used the

subregional modeling as part of the

proposed approach because OTAG had

developed and relied on this modeling

as part of its analysis to quantify the

impacts of manmade emissions in

upwind areas on ozone in downwind

areas. In addition, in conjunction with

other information, EPA believes that it

is possible to make rational

extrapolations from the subregional

results in order to draw conclusions as

to the contribution of individual States.

The EPA believes that it is credible to

use NOx emissions in each State, along

with the subregional modeling results,

in the determination of significance in

view of the results of OTAG modeling

which indicate that, in addition to local

emissions, the level of ozone in a

downwind State is directly related to

the magnitude of NOx emissions in

upwind areas and the proximity of the

upwind area to the downwind State. A

more detailed discussion of the

technical validity of the subregional

modeling is contained in the Response

to Comment Document.

The EPA recognizes that State-byState modeling would provide some

additional precision to the magnitude

and frequency of individual State-toState contributions. In response to the

recommendations for additional

modeling, EPA performed both State-byState UAM–V zero-out modeling and

State-by-State CAMx source

apportionment modeling for many of

the upwind States in the OTAG region

which were proposed as significant

contributors. The EPA’s analysis of the

contributions to downwind

nonattainment using the State-by-State

modeling confirms the overall finding,

based on the proposed subregional

modeling, that the 23 jurisdictions

identified in the proposal significantly

contribute to nonattainment in

downwind States. Specifically, the

subregional modeling indicates that

manmade emissions from sources in

subregions 1 through 9 make large and/

or frequent contributions to 1-hour and

8-hour nonattainment in specific

downwind States. The EPA’s analysis of

the State-by-State modeling

demonstrates that each of the 23

upwind jurisdictions identified through

subregional modeling significantly

contribute to nonattainment in specific

downwind States. In addition, the

results of the State-by-State modeling

show that the specific upwind-State-todownwind-nonattainment linkages

indicated by the subregional modeling

are confirmed overall by the State-byState modeling. The State-by-State

modeling analyses are summarized

below and more fully documented in

the Air Quality Modeling TSD.

Comment: The EPA received

comments that zero-out modeling

introduces sharp spatial changes in

emissions and pollutants along the

edges of the zero-out area. The

commenters contend that this is not

credible and provides an incorrect

assessment of transport.

Response: The EPA disagrees with

this comment, as discussed in the

Response to Comments document. Also,

as indicated above, in response to other

comments, EPA has performed CAMx

source apportionment modeling which

does not use a zero-out technique for

quantifying ozone contributions from

upwind States. In general, EPA has

found that the source apportionment

technique and zero-out modeling
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57385

35For the purposes of discussion in this Section,

these values are referred to as ‘‘design’’ values.

provide consistent information on the

relative contribution of upwind States to

downwind nonattainment. In cases

where the two techniques do not

provide consistent results, the source

apportionment technique tends to

indicate larger contributions than the

zero-out modeling. The differences

between these two modeling techniques

are described further in the Air Quality

Modeling TSD.

Comment: Some comments referenced

a study which analyzed the ‘‘noise’’

(i.e., uncertainty) in the UAM–V

modeling system. This study purports to

show that the contributions from some

States EPA proposed as significant are

within the ‘‘noise’’ of the model.

Response: This study focuses on

model uncertainty by varying many, but

not all, inputs to the model. The study

does not contend that the inputs

selected by OTAG are incorrect, but

rather that there may be other plausible

values for these inputs. The results

indicate that there is a range of

uncertainty in predicted ozone

associated with the range of possible

values for the particular inputs studied

by the commenter. The study does not

indicate that there is any bias in the

model’s predictions (i.e., there is no

indication that the predictions are too

high or too low). The specific values for

the inputs being used by EPA in its air

quality modeling are the same values

that were used by OTAG. These values

were selected by the OTAG Regional

and Urban Scale Modeling Work Group,

which included experts in air quality

modeling from the public and private

sector, in conjunction with the model’s

developers, Systems Application

International. The predictions from

OTAG’s model runs using these same

input values were evaluated against

ambient measurements and found by

OTAG to provide acceptable results.

The EPA continues to believe that the

specific inputs selected by OTAG are

technically sound and the modeling

results are credible. A further discussion

of EPA’s response to this comment is in

the Response to Comments document.

Comment: Several commenters stated

that emissions from large point sources

of NOx in specific States do not

contribute significantly to downwind

nonattainment.

Response: As discussed in Section

II.A.3.c, Definition of Significant

Contribution, under EPA’s collective

contribution approach, if emissions in

the aggregate from a particular

geographic region or State are found to

contribute significantly to

nonattainment downwind, then the

emissions in that region or State are

considered to be significant contributors

to that nonattainment problem.

Moreover, EPA treats emissions as

‘‘contributing significantly’’ only to the

extent they may be eliminated through

highly cost-effective reductions. Thus, if

all emissions from a State, when

considered in the aggregate, are found to

contribute significantly to

nonattainment downwind, and if there

are highly cost-effective controls for

NOx emissions from sources in the

upwind State, then the amount of NOx

emissions from these sources that can be

eliminated with such controls are

considered to be making a significant

contribution. The amount of emissions

determined through this approach to

make a significant contribution may be

relatively small, compared to the

upwind State’s entire inventory; and the

ambient impact downwind of

eliminating that amount may be

relatively small as well. However, this

small impact does not mean that the

emissions themselves are not significant

insofar as their contribution to

nonattainment downwind. Further, as

discussed in Section IV, Air Quality

Assessment, when the amount of

emissions required to be eliminated

from upwind States are combined and

modeled collectively, their ambient

impact downwind is larger.

Comment: One commenter provided a

recommendation for dealing with the

concern that the spatial resolution of

meteorological inputs to the air quality

model may be too coarse to require that

predicted exceedences correspond

exactly with a county violating the

NAAQS. The commenter’s

recommendations were to base the

selection of 1-hour nonattainment

receptors on model predicted

exceedences in either (a) all counties

within the metropolitan statistical area

containing the nonattainment area or (b)

all counties comprising the designated

1-hour nonattainment area.

Response: The EPA believes that the

appropriate way to address this issue is

to use all counties comprising the

designated 1-hour nonattainment area.

That is, all counties in a designated 1-

hour nonattainment area should be

considered as possible nonattainment

receptors for the purposes of evaluating

contributions to nonattainment under

the 1-hour NAAQS. The EPA recognizes

that not all counties within a designated

nonattainment area have monitors, and

that some counties may have monitors

that indicate attainment in that county.

Even so, EPA recognizes that under the

1-hour NAAQS, nonattainment

boundaries are generally used to

describe an area with the nonattainment

problem. Thus, EPA believes that this

geographic vicinity offers the best

indication of an area that may be

expected to have nonattainment air

quality somewhere within its

boundaries. The EPA believes that it is

appropriate to include all counties in

the designated nonattainment area

because the entire nonattainment area is

responsible for meeting the 1-hour

NAAQS, even if only one monitor

measures nonattainment at any one

time. As noted elsewhere, EPA predicts

that many 1-hour nonattainment areas

that currently monitor nonattainment

somewhere within the area will remain

in nonattainment in 2007, in some cases

because of predicted violations in

counties that currently monitor

attainment. The EPA believes that the

entire area should be considered to be

in nonattainment until all monitors in

the area indicate attainment of the

NAAQS. Thus, in today’s rulemaking,

EPA used the designated 1-hour

nonattainment area in selecting the

receptors to be used to evaluate impacts

on downwind nonattainment problems.

Comment: Several commenters

questioned the validity of EPA’s

approach of using the 3-episode average

of the second highest 8-hour daily

maximum concentration to represent

the form of the 8-hour NAAQS (i.e., the

3-year average of the fourth highest 8-

hour daily maximum values at a

monitor 35). Commenters expressed the

concern that the average second high

may not be representative for all areas

across the OTAG domain. However,

none of the commenters provided any

suggested alternatives to EPA’s

approach.

Response: The analysis performed by

EPA to establish a relationship between

the air quality during the OTAG

episodes and the form of the 8-hour

NAAQS was based upon an analysis of

3 years of monitoring data compared to

monitoring data during the OTAG

episodes. In response to comments, EPA

performed an analysis to determine how

the predicted average second high 8-

hour values, as well as several

alternative 8-hour values, compared to

ambient 8-hour design values, based on

1994 to 1996 measured data. Based on

this analysis, EPA determined that,

overall, the model-predicted average

second high values underestimate the

corresponding ambient design values for

those counties in the OTAG domain

with 1994–1996 ambient values >=85

ppb. In addition to the average second

high, EPA also compared six other

measures of 8-hour model predictions to

ambient design values. The six other

measures include the highest, second
57386 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

36Similarly, the EPA is also using 1-hour model

predictions >=125 ppb as an indicator that areas

currently designated nonattainment for the 1-hour

NAAQS will continue to be nonattainment for the

1-hour NAAQS in 2007.

37As explained elsewhere, for the 1-hour

standard, EPA based its determination as to the

boundaries of the area with air quality violating the

NAAQS on the boundaries of the area designated

as nonattainment.

38 Indeed, the modeling relied on in today’s action

indicates that many downwind nonattainment areas

carry a residual nonattainment problem even after

implementation of regional reductions by all the

States affected by today’s action. Although not

essential to EPA’s conclusions, the presence of this

nonattainment problem even after implementation

of regional controls, based on the modeling used in

today’s rulemaking, indicates that even further

reductions, regionally or locally, would be needed

to assure attainment in those downwind areas.

highest, third highest, and fourth

highest ozone predictions across the

July 1991, 1993, and 1995 episodes; the

3-episode average of the highest

concentrations; and the 3-episode

average of the highest, second highest,

and third highest concentrations. The

EPA also developed the same measures

using model predictions from all 4

episodes for comparison to the ambient

design values. The results indicate that

none of the alternative measures

provides a universal best match to

ambient 8-hour design values in all

States. Each of the indicators

overestimates values in some areas and

underestimates values in other areas to

a varying extent. Furthermore, the best

representation of 8-hour design values

using predictions from the OTAG

episodes varies from State to State.

Given that the predicted average second

high underestimates ambient 8-hour

design values and that none of the other

8-hour indicators examined by EPA

provides a ‘‘best’’ match to ambient

values in all cases, EPA has decided to

analyze the contributions to 8-hour

nonattainment problems using all 8-

hour predictions >=85 ppb. The EPA

believes that this approach is

appropriate given that EPA is using

modeling results for the 8-hour NAAQS

merely as an indicator of the likelihood

that areas that currently monitor

violations of the 8-hour NAAQS will

continue to be nonattainment for the 8-

hour NAAQS and/or have 8-hour

maintenance problems in 2007.36 Thus,

the air quality analysis of 8-hour

contributions, described below, focuses

on all 8-hour values >=85 ppb.

Comment: Several commenters

submitted new State-by-State zero-out

modeling using UAM–V and CAMx

source apportionment modeling

purporting to show that contributions

from particular upwind States are

insignificant.

Response: The EPA reviewed the

commenters’ modeling to determine and

assess (a) the technical aspects of the

models that were applied; (b) the types

of episodes modeled; (c) the methods for

aggregating, analyzing, and presenting

the results; (d) the completeness and

applicability of the information

provided; and (e) whether the technical

evidence supports the arguments made

by the commenters. Overall, the

modeling submitted by commenters is

viewed by EPA as generally technically

credible, although not complete in all

cases. The EPA’s ability to fully evaluate

and utilize the modeling submitted by

commenters was hampered in some

cases because only limited information

on the results was provided. For

example, a commenter may have

provided results for only 1 or 2 days in

an episode, or for only one of several

episodes with no information presented

on the results for the remaining days or

episodes that were modeled. As another

example, results were presented for only

the peak ozone day in an episode while

greater contributions may have been

predicted on other high ozone days of

the episode. For some of the modeling,

the information was only presented in

graphical form which made the results

difficult to evaluate in a quantitative

way. Also, in some cases the model

predictions were only presented as

episode composite values without

information on peak contributions. The

EPA’s full assessment of the modeling

submitted by commenters is provided in

the Response to Comments document.

In light of the absence of complete

information in the modeling provided

by commenters and other comments

calling for State-by-State analyses, EPA

decided to perform additional air

quality modeling of the type submitted

by commenters in order to consider all

of the data resulting from such model

runs. The EPA modeling includes Stateby-State zero-out modeling using UAM–

V and State-by-State CAMx source

apportionment modeling.

EPA conducted further analysis of

other factors included in the multifactor approach for significant

contribution. The results of EPA’s

consideration of these factors and EPA’s

modeling are described next.

3. Analysis of State-specific Air Quality

Factors

a. Overall Nature of Ozone Problem

(‘‘Collective Contribution’’). As

described above, EPA believes that each

ozone nonattainment problem at issue

in today’s rulemaking is the result of

emissions from numerous sources over

a broad geographic area. The

contribution from sources in an upwind

State must be evaluated in this context.

This ‘‘collective contribution’’ nature of

the ozone problem supports the

proposition that the solution to the

problem lies in a range of controls

covering sources in a broad area,

including upwind sources that cause a

substantial portion of the ozone

problem. This upwind share is typically

caused by NOx emissions from sources

in numerous States. States adjacent to

the State with the nonattainment

problem generally make the largest

contribution, but States further upwind,

collectively, make a contribution that

constitutes a large percentage in the

context of the overall problem. As an

example to illustrate the overall nature

of the ozone problem, EPA discusses

below the ozone problem in the New

York City nonattainment area.

b. Extent of Downwind

Nonattainment Problems. For each

downwind area to which an upwind

State may be linked, EPA also examined

the extent of the downwind

nonattainment problem, including the

air quality impacts of controls required

in downwind areas under the CAA, as

well as of controls required or

implemented on a national basis. As

indicated elsewhere, EPA determined

that a downwind area should be

considered ‘‘nonattainment’’ for

purposes of section 110(a)(2)(D)(i)(I)

under the 1-hour NAAQS if the area

currently (as of the 1994–96 time

period) has nonattainment air quality 37

and if the area is modeled to have

nonattainment air quality in the year

2007, after implementation of all

measures specifically required of the

area under the CAA as well as

implementation of Federal measures

required or expected to be implemented

by that date. The EPA determined that

each such downwind area had a

residual nonattainment problem even

after implementation of all these control

measures. The presence of residual

nonattainment is a factor that supports

the need to reduce emissions from

upwind sources to allow further

progress towards attainment.38 As an

example, the residual nonattainment for

the New York City area is discussed in

more detail below.
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57387

39For ease of discussion, EPA is using the term

‘‘UAM–V’’ to refer to the UAM–V State-by-State

zero-out modeling and the term ‘‘CAMx’’ to refer to

the CAMx source apportionment modeling.

40For ease of discussion in this Section, the 1-

hour nonattainment areas and the set of

nonattainment receptors pooled over an entire State

are referred to as downwind areas.

41High measured ozone concentrations in

portions of Illinois, Indiana, Michigan, and

Wisconsin near the shoreline of Lake Michigan are

often associated with weather conditions which

cause ozone precursor pollutants to be blown

offshore over the lake during the morning, where

they can form high ozone concentrations which

then return onshore during ‘‘lake breeze’’ wind

flows in the afternoon. Because the size of the grid

cells used in the OTAG modeling is relatively large

compared to the spatial scale of the lake breeze, the

high ozone concentrations predicted over the lake

may not be blown back onshore in the model. Since

high concentrations over the lake do, in reality,

impact air quality along the shoreline of one or

more of these States, the EPA believes that it is

appropriate to use predicted contributions to ozone

over Lake Michigan as a surrogate for contributions

to any one of the surrounding States (i.e., Illinois,

Indiana, Michigan, and Wisconsin).

c. Air Quality Impacts of Upwind

Emissions on Downwind

Nonattainment. As indicated above, in

response to comments, additional air

quality modeling was performed by EPA

to confirm the proposed approach

which relied on subregional modeling to

quantify the impacts of emissions from

upwind States on nonattainment in

downwind areas. The additional

modeling consisted of State-by-State

zero-out modeling using UAM–V and

State-by-State source apportionment

modeling using the CAMx

Anthropogenic Precursor Culpability

Assessment (APCA) technique.39 A

description of these models is contained

in the Air Quality Modeling TSD. Both

models are currently being used by the

scientific and regulatory community for

air quality assessments. The EPA is not

aware of any information that would

indicate that either model provides

more credible predictions than the

other. Each modeling technique (i.e.,

zero-out and source apportionment)

provides a different technical approach

to quantifying the downwind impact of

emissions in upwind States. The zeroout modeling analysis provides an

estimate of downwind impacts by

comparing the model predictions from a

Base Case run to the predictions from a

run in which the Base Case manmade

emissions are removed from a specific

State. In contrast, the source

apportionment modeling quantifies

downwind impacts by tracking

formation, chemical transformation,

depletion, and transport of ozone

formed from emissions in an upwind

source area and the impacts that ozone

has on nonattainment in downwind

areas. The EPA ran both models for all

four OTAG episodes (i.e., July 1–11,

1988; July 13–21, 1991; July 20–30,

1993; and July 7–18, 1995) using the

2007 SIP Call Base Case emissions. The

development of emissions for this Base

Case scenario are described in Section

IV, Air Quality Assessment.

The EPA selected several metrics in

order to evaluate the downwind

contributions from emissions in upwind

States. The metrics were designed to

provide information on the three

fundamental factors for evaluating

whether emissions in an upwind State

make large and/or frequent

contributions to downwind

nonattainment. These factors are (a) the

magnitude of the contribution, (b) the

frequency of the contribution, and (c)

the relative amount of the contribution.

The magnitude of contribution factor

refers to the actual amount of ‘‘ppbs’’ of

ozone contributed by emissions in the

upwind State to nonattainment in the

downwind area. The frequency of the

contribution refers to how often the

contributions occur and how extensive

the contributions are in terms of the

number of grids in the downwind area

that are affected by emissions in the

upwind State. The relative amount of

the contribution is used to compare the

total ‘‘ppb’’ contributed by the upwind

State to the total ‘‘ppb’’ of

nonattainment in the downwind area.

As indicated above, two modeling

techniques (i.e., UAM–V zero-out and

CAMx source apportionment) were used

for the State-by-State evaluation of

contributions. The EPA developed

metrics for both modeling techniques

for each of the three factors. However,

because of the differences between the

two techniques, some of the metrics

used for the UAM–V modeling and the

CAMx modeling are different. The

specific UAM–V and CAMx metrics and

how they relate to the three factors used

for the evaluation of contributions are

described below.

The EPA examined the contributions

from upwind States to downwind

nonattainment for several types of

nonattainment receptors. Nonattainment

receptors for the 1-hour analysis include

those grid cells that (a) are associated

with counties designated as

nonattainment for the 1-hour NAAQS

and (b) have 1-hour Base Case model

predictions >=125 ppb. These grid cells

are referred to as ‘‘designated plus

modeled’’ nonattainment receptors.

Using these receptors, the metrics were

calculated for each 1-hour

nonattainment area as well as for each

State. To calculate the metrics by State,

all of the 1-hour nonattainment

receptors in that State were pooled

together.40 Table II–1 lists the 1-hour

nonattainment areas that were

considered in this analysis, along with

the State(s) in which the nonattainment

area is located. In addition to the areas

listed in Table II–1, EPA also evaluated

the contributions of upwind States to

ozone concentrations over Lake

Michigan because modeled air quality

over the lake can be indicative, under

certain weather conditions, of air

quality in portions of the States

surrounding the lake.41

TABLE II–1.—1-HOUR NONATTAINMENT AREAS EVALUATED

Nonattainment area State(s)

Atlanta ................................................................. Georgia.

Baltimore ............................................................. Maryland.

Birmingham ......................................................... Alabama.

Boston/Portsmouth 1 ........................................... Massachusetts, New Hampshire.

Chicago/Milwaukee 2 ........................................... Illinois, Indiana, Wisconsin.

Cincinnati ............................................................ Kentucky, Ohio.

Greater Connecticut ............................................ Connecticut.

Louisville ............................................................. Indiana, Kentucky.

Memphis .............................................................. Mississippi, Tennessee.

New York City ..................................................... Connecticut, New Jersey, New York.

Philadelphia ......................................................... Delaware, Maryland, New Jersey, Pennsylvania.

Pittsburgh ............................................................ Pennsylvania.

Portland ............................................................... Maine.

Rhode Island ....................................................... Rhode Island.

Southwestern Michigan 3 ..................................... Michigan.
57388 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

42Model predictions from the first few days of

each episode are considered ‘‘ramp-up’’ days and

were excluded from the analysis, following the

procedures adopted by OTAG. The ramp-up days

include the first 3 days of the July 1988, 1991, and

1995 episodes and the first 2 days of the July 1993

episode.

TABLE II–1.—1-HOUR NONATTAINMENT AREAS EVALUATED—Continued

Nonattainment area State(s)

St. Louis .............................................................. Illinois, Missouri.

Washington, DC .................................................. District of Columbia, Maryland, Virginia.

Western Massachusetts ...................................... Massachusetts.

1For the purposes of this analysis EPA has combined the Greater Boston nonattainment area which includes portions of Massachusetts and

New Hampshire, with the Portsmouth, New Hampshire nonattainment area into a single downwind nonattainment receptor area. 2For the purposes of this analysis EPA has combined the 1-hour nonattainment counties that are along the shoreline of Lake Michigan in the

States of Illinois, Indiana, and Wisconsin into a single downwind nonattainment receptor area. 3For the purposes of this analysis EPA has combined the 1-hour nonattainment counties that are along the shoreline of Lake Michigan in the

State of Michigan into a single downwind nonattainment receptor area.

For the 8-hour analysis,

nonattainment receptors are those grid

cells that (a) are associated with

counties currently violating the 8-hour

NAAQS (based on 1994–1996 data) and

(b) have 8-hour Base Case model

predictions >=85 ppb. These grid cells

are referred to as ‘‘violating plus

modeled’’ nonattainment receptors. The

metrics for the 8-hour contribution

analyses were calculated on a State-byState basis by pooling together the

‘‘violating plus modeled’’ receptors in a

State.

(1) UAM–V State-by-State Modeling.

In the UAM–V zero-out model runs all

manmade emissions in a given upwind

State were removed from the Base Case

scenario. Each zero-out scenario was

run for all 4 episodes and the ozone

predictions in downwind States were

then compared to those from the Base

Case run in order to quantify the

downwind impacts of emissions from

the upwind State (i.e., the State in

which the manmade emissions were

removed). The EPA performed zero-out

runs for the following set of States:

• Alabama, Georgia, Illinois, Indiana,

Kentucky, Massachusetts, Michigan,

Missouri, North Carolina, Ohio, South

Carolina, Tennessee, Virginia, West

Virginia, and Wisconsin.

Zero-out modeling for Massachusetts

was performed because this State was

the only State in the Northeast with

relatively large NOX emissions that was

not included in any of the OTAG

subregional modeling. The other States

listed above were selected for zero-out

modeling in order to respond to

comments that emissions in all or

portions of each of these States do not

contribute significantly to downwind

nonattainment.

The EPA analyzed the modelpredicted ozone concentrations from the

zero-out runs using the four metrics

described below. The results for these

metrics are too voluminous to include

in the notice in their entirety. The full

set of results is contained in the Air

Quality Modeling TSD. Each metric was

calculated using 1-hour daily maximum

concentrations >=125 ppb as well as 8-

hour daily maximum concentrations

>=85 ppb. Model predictions from all 4

episodes were used for calculating the

metrics.42

UAM–V Metric 1: Exceedences. This

metric is the total number of predicted

concentrations exceeding the NAAQS

(i.e. 1-hour values >=125 ppb and 8-

hour values >=85 ppb) within the

downwind area. In calculating this

metric, EPA summed the number of

occurrences of values above the

applicable standard (i.e., 1-hour or 8-

hour) for all nonattainment receptors

within the downwind area. For

example, in Downwind Area #1 there

are five 1-hour ‘‘designated plus

modeled’’ nonattainment receptors. For

this downwind area, the Base Case

value for Metric 1 is calculated by first

counting the number of days, across all

four episodes, that had 1-hour daily

maximum values >=125 ppb at each of

the five receptors. The result is the total

number of exceedences at each receptor

over all days in all four episodes. The

total number of exceedences at each

receptor is then summed across all five

receptors to produce the total number of

exceedences in Downwind Area #1,

which is the value for Metric 1 for this

area.

UAM–V Metric 2: Ozone Reduced—

ppb. This metric shows the magnitude

and frequency of the ‘‘ppb’’ impacts

from each upwind State on ozone

concentrations in each downwind area.

These impacts are quantified by

calculating the difference in ozone

concentrations between the zero-out run

and the Base Case. The results are then

tabulated in terms of the number of

‘‘impacts’’ within six concentration

ranges: >=2 to 5 ppb, >=5 to 10, >=10

to 15, >=15 to 20, >=20 to 25, and >=25

ppb. The impacts for 1-hour daily

maximum values and 8-hour daily

maximum values are determined by

tallying the total ‘‘number of days and

grid cells’’ >=125 ppb or >=85 ppb that

receive contributions within the

concentration ranges. In the analysis of

contributions, as described below, the

data from Metric 2 are used in

conjunction with Metric 1 to determine

the percent of the exceedences in the

downwind area that receive

contributions of >=2 ppb, >= 5 ppb,

>=10, ppb, etc. The maximum ‘‘ppb’’

impact within the downwind area is

also calculated.

UAM–V Metric 3: Total ppb Reduced.

This metric quantifies the total ppb

contributed in the downwind area from

an upwind State, not including that

portion of the contribution that occurs

below the level of the NAAQS. For 1-

hour concentrations, Metric 3 is

calculated by taking the difference

between the Base Case predictions in

each nonattainment receptor and either

(a) the corresponding value in the zeroout run, or (b) 125 ppb, whichever is

greater (i.e., 125 ppb or the prediction

in the zero-out run). The Base Case vs.

zero-out differences are summed over

all days and across all nonattainment

receptors in the downwind area. The

calculation of this metric is illustrated

by the following example. If the Base

Case 1-hour daily maximum ozone

prediction is 150 ppb and the

corresponding value from the zero-out

run is 130 ppb, then the difference used

in this metric is 20 ppb. However, if the

value from the zero-out run is 115 ppb,

then the difference used in this metric

is 25 ppb (i.e., 150 ppb–125 ppb,

because 115 ppb is less than 125 ppb).

For analyzing the contributions using

Metric 3, the values of this metric are

compared to the total amount of ozone

above the NAAQS (i.e., 125 ppb, 1-hour

or 85 ppb, 8-hour) in the Base Case. This

baseline measure of the ‘‘total amount of

nonattainment’’ (i.e., the total ‘‘ppb’’ of

ozone that is above the NAAQS) is

calculated by summing the ‘‘ppb’’

values in the Base Case that are above

the level of the NAAQS. The total

contribution from an upwind State to a

particular downwind area calculated by

Metric 3 is expressed in relation to the
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57389

43As described in the Air Quality Modeling TSD,

the metrics calculated using the hourly

contributions >= 125 ppb are consistent with the

metrics calculated using 1-hour daily maximum

contributions >= 125 ppb. Similarly, the metrics

calculated using all 8-hour periods >= 85 ppb are

consistent with the metrics calculated using 8-hour

daily maximum values >= 85 ppb.

amount that the downwind area is in

nonattainment. For example, if Upwind

State #1 contributes a total of 50 ppb

>=125 ppb to Downwind Area #2 and

the total Base Case ozone >=125 ppb in

Downwind Area #2 is 500 ppb, then the

contribution from Upwind State #1 (i.e.,

50 ppb) to Downwind Area #2 is

equivalent to 10 percent of Downwind

Area #2’s nonattainment problem (i.e.,

50 ppb divided by 500 ppb, times 100).

UAM–V Metric 4: PopulationWeighted Total ppb Reduced. This

metric is similar to the ‘‘Total ppb

Reduced’’ metric except that the

calculated contributions are weighted

by (i.e., multiplied by) population. In

calculating this metric, the ‘‘ppb’’

contributions are determined for each

nonattainment receptor, then summed

across all nonattainment receptors in a

particular downwind area. During this

calculation, the population in the

nonattainment receptor is multiplied by

the total contribution in that receptor

(i.e., grid cell) and then this value is

added to the corresponding values for

the other receptors in the downwind

area. The results for this metric are

expressed relative to the populationweighted Base Case amount similar to

the approach followed with Metric 3, as

described above.

(2) CAMx Source Apportionment

Modeling. In the CAMx modeling, the

source apportionment technique was

used to calculate the contributions from

upwind States to ozone concentrations

above the NAAQS in downwind areas.

Due to computational constraints, it was

not possible for EPA to treat each State

in the OTAG region as a separate source

area. Several of the smaller States in the

Northeast were grouped together as

were seven States in the far western

portion of the region. The following

States were treated as individual source

areas:

• Alabama, Florida, Georgia, Illinois,

Indiana, Iowa, Kentucky, Louisiana,

Maine, Massachusetts, Michigan,

Mississippi, Missouri, New Jersey, New

York, North Carolina, Ohio,

Pennsylvania, South Carolina,

Tennessee, Texas, Virginia, West

Virginia, and Wisconsin.

The following States were grouped

together:

• Connecticut and Rhode Island were

combined; Maryland, Delaware and the

District of Columbia were combined;

New Hampshire and Vermont were

combined; and Arkansas was combined

with the portions of Oklahoma, Kansas,

Minnesota, Nebraska, North Dakota, and

South Dakota that lie within the OTAG

region.

The contributions from each of these

source areas to downwind

nonattainment were evaluated using

four metrics. As indicated above, the

CAMx metrics are calculated for the

same types of nonattainment receptors

as the UAM–V zero-out metrics. The

CAMx metrics are calculated in a way

that is different from the metrics used

for the zero-out runs in large part

because of the differences between the

two techniques. The zero-out modeling

calculates contributions using the

difference in predictions between two

model runs (i.e., a Base Case and a

State-specific zero-out run). In contrast,

the CAMx source apportionment

technique calculates contributions by

internally tracking ozone formed from

emissions in each source area. In raw

form, the source apportionment

technique produces a ‘‘ppb’’

contribution from each source area to

hourly ozone in each receptor grid cell.

The individual hourly ‘‘ppb’’

contributions were treated in the way

described below to calculate 1-hour and

8-hour values for the four metrics. The

approach was based on

recommendations to EPA by Environ,

the developers of CAMx. For 1-hour

concentrations the metrics are

calculated based on contributions to all

hourly predictions >=125 ppb. For 8-

hour concentrations, the metrics are

calculated based on the contribution to

every 8-hour period in a day with an

average concentration >=85 ppb. In

order to provide a link to the way 1-

hour and 8-hour concentrations were

treated for the zero-out runs, EPA also

calculated the CAMx metrics for 1-hour

daily maximum values >=125 ppb and

8-hour daily maximum values >=85

ppb. 43 The full set of results for all of

the CAMx metrics is contained in the

Air Quality Modeling TSD.

The CAMx Metrics 1 and 2 provide

information on the magnitude and

frequency of contributions in a form that

is similar to UAM–V Metrics 1 and 2.

CAMx Metric 3: Highest Daily

Average Contribution. This metric is the

highest daily average ozone ‘‘ppb’’

contribution from each upwind source

area to each downwind nonattainment

receptor area over all days modeled in

all four episodes. The following

example illustrates how this metric is

calculated for 1-hour ozone

concentrations. Similar procedures are

followed for calculating this metric for

8-hour concentrations. First, the hourly

‘‘ppb’’ contributions from a particular

upwind source area to each

nonattainment receptor in a downwind

area are summed across all receptors in

the downwind area. This total daily

contribution is then divided by the

number of hours and grid cells >=125

ppb in the downwind area to determine

the daily average ‘‘ppb’’ contribution.

This calculation is performed on a day

by day basis for each day in the 4

episodes. After the average

contributions are calculated for each

day, the highest daily average value

across all episodes is selected for

analysis. In addition, the highest daily

average contribution is expressed as a

percent of the downwind area’s average

ozone >=125 ppb. That is, the highest

daily average ‘‘ppb’’ contribution is

divided by the average of the ozone

concentrations >=125 ppb on that day

(i.e., the day on which the highest

average ppb contribution occurred). For

example, if the highest daily average

contribution from an upwind State to

nonattainment downwind is 15 ppb and

the average of the hourly ozone values

>=125 ppb on this day in the downwind

area is 150 ppb, then the 15 ppb

contribution, expressed as a percent, is

10 percent.

CAMx Metric 4: Percent of Total

Manmade Ozone Contribution. This

metric represents the total contribution

from emissions in an upwind State

relative to the total ozone for all hours

above the NAAQS in the downwind

area. This metric, which is referred to as

the ‘‘average contribution,’’ is calculated

for each episode as well as for all four

episodes combined. The following

example is used to illustrate how this

metric is calculated for a single episode

for a particular downwind area. In step

1, all predicted Base Case hourly values

>=125 ppb in the downwind area are

summed over all nonattainment

receptors and all days in an episode. In

step 2, the ‘‘ppb’’ contributions from a

source area to this downwind area are

summed over all nonattainment

receptors in the downwind area and all

days in the episode to yield a total ppb

contribution. The total contribution

calculated in Step 2 is then divided by

the total ozone >=125 ppb in the

downwind area to produce the fraction

of ozone >=125 ppb in the downwind

area that is due to emissions from the

upwind source area. This fraction is

multiplied by 100 to express the result

as a percent.

4. Confirmation of States Making a

Significant Contribution to Downwind

Nonattainment

In the proposal, EPA made findings of

significant contribution based on a
57390 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

44The approach for dealing with the 15 States in

the OTAG domain which were not proposed to

make a significant contribution to downwind

nonattainment are discussed below in Section

II.C.5, States Not Covered by this Rulemaking.

45Scenarios (b) and (c) refer to the runs used to

assess transport as described in Section IV.

46This information represents the average

contributions across all four episodes. In addition

to the four-episode average contribution, EPA also

examined the highest single-episode average

contribution from each upwind State to each

downwind area.

47The factors used to interpret the metrics should

not be confused with the multi-factor approach

used to identify the amounts of NOX emissions that

contribute signficantly to nonattainment.

weight-of-evidence approach that

included consideration of air quality

contributions based on subregional

modeling. As discussed in section II.C.2,

Summary of Notice of Proposed

Rulemaking Weight-of-Evidence

Approach, EPA believes that the

subregional modeling provides an

adequate independent basis for

determining which States contribute

significantly to downwind

nonattainment. The evaluation of the

State-by-State modeling confirms the

overall findings that were based on the

subregional modeling and provides

more refined information regarding the

impacts of specific upwind States on

nonattainment in individual downwind

areas. This State-by-State modeling is

discussed in more detail below.

a. Analysis Approach. The EPA has

analyzed the results of the State-by-State

UAM–V zero-out modeling and the

State-by-State CAMx source

apportionment modeling for each of the

23 jurisdictions for which this modeling

is available.44 Both UAM–V and CAMx

modeling results are available for fifteen

States (i.e., Alabama, Georgia, Illinois,

Indiana, Kentucky, Massachusetts,

Michigan, Missouri, North Carolina,

Ohio, South Carolina, Tennessee,

Virginia, West Virginia, and Wisconsin).

For an additional eight States (i.e.,

Connecticut, Delaware, the District of

Columbia, Maryland, New Jersey, New

York, Pennsylvania, and Rhode Island),

CAMx modeling is available. Also, as

noted above in Section II.C.3, State-byState Air Quality Modeling, Connecticut

and Rhode Island were combined as a

single source area, and Maryland, the

District of Columbia, and Delaware were

also combined as a single source area.

Because the NOX emissions and/or NOX

emissions density is large in each

jurisdiction within both of these

combined source areas, EPA believes

that the downwind contributions from

these combined source areas can be

attributed to each jurisdiction within

the source area.

For the 1-hour NAAQS, EPA

evaluated downwind impacts in two

ways using the factors described in

Section II.C.3, State-by-State Air Quality

Modeling. First, EPA evaluated the

contributions from each upwind State to

nonattainment in each downwind State.

Second, the EPA evaluated the

contributions from each upwind State to

nonattainment in each downwind 1-

hour nonattainment area. In downwind

States which only contain a single

intrastate nonattainment area (e.g.,

Atlanta), the results of the downwind

State and downwind nonattainment

area analyses are the same because the

same nonattainment receptors are used

in both cases. For the 8-hour NAAQS,

EPA evaluated the contributions from

upwind States to 8-hour nonattainment

in each downwind State.

The EPA used the following process

in determining whether a particular

upwind State contributes significantly

to 1-hour nonattainment in an

individual downwind area. First, EPA

reviewed the extent of the

nonattainment problem in the

downwind area using ambient design

values and model predictions of future

ozone concentrations after the

application of (a) 2007 Base Case

controls, (b) additional local NOX

reductions, and (c) regional reductions

(additional local plus upwind NOX

reductions).45 As indicated above, EPA

determined that each downwind area

had a residual nonattainment problem

even after implementation of the control

measures in the 2007 Base Case.

Second, using the information from

CAMx Metric 4 46, EPA reviewed (a) the

relative portion of the ozone problem in

each downwind area that is due to

‘‘local’’ emissions (i.e., emissions from

the entire State or States in which the

downwind area is located), (b) the total

contribution from all upwind emissions

(i.e., the sum of the contributions from

manmade emissions in all upwind

States, combined), and (c) the

contribution from manmade emissions

in individual upwind States. The local

versus upwind contributions for each

downwind area are provided in the Air

Quality Modeling TSD. The EPA

analyzed this information to determine

whether upwind emissions are an

important part of the downwind areas’

nonattainment problem. In general, the

data indicate that, although a substantial

portion of the 1-hour nonattainment

problem in many of the downwind areas

is due to local emissions, a substantial

portion of the nonattainment problem is

also due to emissions from upwind

States. In addition, for most upwindState-to-downwind-area linkages there

is no single upwind State that makes up

all of the upwind contribution. Rather,

the total contribution for all upwind

States combined is comprised of

individual contributions from a number

of upwind States many of which are

relatively similar in magnitude such

that there is no ‘‘bright line’’ which

distinguishes between the contributions

from most of the individual upwind

States.

Third, EPA determined whether each

individual upwind State significantly

contributes to nonattainment in a

particular downwind area using the

UAM–V and CAMx metrics to evaluate

three aspects, or factors of the

contribution.47 These factors include the

magnitude, frequency, and relative

amount of the contribution. The specific

UAM–V and CAMx metrics which

correspond to each of the factors are

identified in Table II–2. As indicated in

the table, there is at least one metric

from each modeling technique that

corresponds to each of the three factors.

TABLE II–2.—METRICS ASSOCIATED WITH EACH CONTRIBUTION FACTOR

Factor UAM–V CAMx

Magnitude of Contribution .... Maximum ‘‘ppb’’ contribution (Metric 2) Maximum ‘‘ppb’’ Contribution (Metric 2); and Highest

Daily Average Contribution (Metric 3).

Frequency of Contribution .... Number and percent of exceedences with contributions

in various concentration ranges (Metric 1 and 2)

Number and percent of exceedences with contributions

in various concentration ranges (Metric 1 and 2).

Relative Amount of Contribution.Total ‘‘ppb’’ contribution relative to the total ‘‘ppb’’ that

the downwind area is above the NAAQS (Metric 3);

and Total population-weighted ‘‘ppb’’ contribution relative to the total population-weighted ‘‘ppb’’ that the

downwind area is above the NAAQS (Metric 4)

Four-episode average percent contribution from the

upwind State to nonattainment in the downwind area

(Metric 4); and Highest single-episode average percent contribution from the upwind State to nonattainment in the downwind area (Metric 4).
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57391

48This is further described in the Air Quality

Modeling TSD.

It should be noted that the relative

contributions of individual upwind

States to a particular downwind area

add up to 100 percent for the CAMx 4-

episode average percent contribution.

However, this is not the case for the

CAMx highest single-episode average

percent contribution since the value

from one upwind State can occur in a

different episode than the value from

another upwind State for the same

downwind area. In addition, it should

be noted that UAM–V Metrics 3 and 4

are used in combination to express the

total contribution above the NAAQS

relative to the total amount that the

downwind area is above the NAAQS.

The values for each of these metrics also

do not add up to 100 percent when

considering contributions from multiple

upwind States to an individual

downwind area.

The EPA compiled the UAM-V and

CAMx metrics by downwind area in

order to evaluate the contributions to

downwind nonattainment. The data on

1-hour and 8-hour contributions were

compiled and analyzed separately. The

data were reviewed to determine how

large of a contribution a particular

upwind State makes to nonattainment

in each downwind area in terms of the

magnitude of the contribution and the

relative amount of the total

contribution. The data were also

examined to determine how frequently

the contributions occur.

The first step in evaluating this

information was to screen out linkages

for which the contributions were very

low, as described in the Air Quality

Modeling TSD. The finding of

significance for linkages that passed the

initial screening criteria was based on

EPA’s technical assessment of the

values for the three contribution factors.

Each upwind State that had large and/

or frequent contributions to the

downwind area, based on these factors,

is considered as contributing

significantly to nonattainment in the

downwind area. The EPA believes that

each of the factors provides an

independent legitimate measure of

contribution. However, there had to be

multiple factors that indicate large and/

or frequent contributions in order for

the linkage to be significant. In this

regard, the finding of a significant

contribution for an individual linkage

was not based on any single factor.

For many of the individual linkages

the factors yield a consistent result (i.e.,

either large and/or frequent

contributions or small and/or infrequent

contributions). In some cases, however,

not all of the factors are consistent. For

upwind-downwind linkages in which

some of the factors indicate high and/or

frequent contributions while other

factors do not, EPA considered the

overall number and magnitude of those

factors that indicate large and/or

frequent contributions compared to

those factors that do not. Based on an

assessment of all the factors in such

cases, EPA determined that the upwind

State contributes significantly to

nonattainment in the downwind area if

on balance the factors indicate large

and/or frequent contributions from the

upwind State to the downwind area.

The EPA’s evaluation of the

contributions to 1-hour nonattainment

in New York City is presented as an

example to illustrate this process. The

New York City area, which consists of

portions of New York, New Jersey, and

Connecticut, is designated as a severe

nonattainment area under the 1-hour

NAAQS. The ambient 1-hour design

value in New York City, based on 1994

through 1996 monitoring data is 144

ppb. During the four OTAG episodes, 39

percent of the days are predicted to have

1-hour exceedences in 2007 after the

implementation of all CAA controls and

Federal measures.48 Moreover, EPA’s air

quality modeling of the benefits of

regional NOX strategies, as described in

Section IV, Air Quality Assessment,

indicates that there would still be

exceedences of the 1-hour NAAQS

remaining in New York City even with

eliminating the significant amounts of

emissions required by this NOX SIP

Call.

In the assessment of contributions to

New York City, EPA examined the local

versus upwind contributions to 1-hour

nonattainment in this area, as shown in

Table II–3. Local emissions in the New

York City nonattainment area are spread

among numerous stationary sources,

area sources, highway sources, and

nonroad sources, each of which

contributes only a very small, indeed

sometimes immeasurable, amount to

New York City’s ozone nonattainment

problem. Combined, these emissions

result in approximately 55 percent of

the New York City area’s ozone

problem. Emissions from States upwind

of New York, New Jersey, and

Connecticut, on average across all four

episodes, contribute 45 percent of the

nonattainment problem in New York

City is due to. However, no single State

stands out as contributing most of the

total upwind contribution. The biggest

single contributor is Pennsylvania (18

percent) followed by Maryland/

Washington, DC/Delaware (5 percent).

The total contribution from all

Northeast States is 23 percent. A similar

amount (22 percent) of the total

contribution is due to emissions in

those States outside the Northeast. The

data in Table II–3 indicate that 19

percent of the 22 percent is fairly evenly

divided among ten States, whose

contributions range from 1 percent (6

States) to 4 percent (Ohio and Virginia).

The remaining 3 percent (i.e., 19 percent

vs 22 percent) is from States that each

contribute less than 1 percent, on

average. The highest single-episode

contributions from States upwind of the

Northeast range from 1 percent

(Tennessee) to 8 percent (Virginia). In

general, the contribution data in Table

II–3 indicate that a substantial amount

of New York City’s nonattainment

problem is due to the collective

contribution from emissions in a

number of upwind States both within

and outside the northeast. That these

upwind contributions are a meaningful

part of New York City’s nonattainment

problem is particularly evident in light

of the fact that the contribution to the

problem made by New York City itself

is comprised of the collective

contribution of numerous sources.

TABLE II–3.—PERCENT CONTRIBUTION FROM UPWIND STATES TO 1-HOUR NONATTAINMENT IN NEW YORK CITY 1

Downwind area: New York City

Percent of

total manmade

emissions

over 4 episodes

Highest singleepisode percent

contribution 2

Amount due to ‘‘Local’’ Emissions 3 ......................................................................................................................... 55 4NA

Total Amount from all ‘‘Upwind’’ States ................................................................................................................... 45 NA

Contributions from Individual Upwind States ........................................................................................................... ........................ ........................

PA ............................................................................................................................................................................. 18 19

MD/DC/DE ................................................................................................................................................................ 5 6
57392 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

49For New York City, each of the ‘‘Group 2’’

States were found to make a significant

contribution. However, this was not the case for all

of the Group 2 linkages in other nonattainment

areas. For example, the contribution from Kentucky

to Philadelphia and the contribution from

Tennessee to Baltimore were Group 2 situations in

which EPA determined that the contributions were

not significant.

TABLE II–3.—PERCENT CONTRIBUTION FROM UPWIND STATES TO 1-HOUR NONATTAINMENT IN NEW YORK CITY 1—

Continued

Downwind area: New York City

Percent of

total manmade

emissions

over 4 episodes

Highest singleepisode percent

contribution 2

OH ............................................................................................................................................................................ 4 6

VA ............................................................................................................................................................................. 4 8

WV ............................................................................................................................................................................ 3 7

IL .............................................................................................................................................................................. 2 3

IN .............................................................................................................................................................................. 1 2

KY ............................................................................................................................................................................. 1 3

MI ............................................................................................................................................................................. 1 4

MO ............................................................................................................................................................................ 1 2

NC ............................................................................................................................................................................ 1 2

TN ............................................................................................................................................................................. 1 1

Total Amount from All Other States, combined ....................................................................................................... 3 NA.

1These values are based on CAMx Metric 3 calculated across all 4 episodes.

2These values are based on CAMx Metric 3 calculated for each episode individually. These values do not add up to 100 percent.

3 3. Total contribution from the State(s) in which the Nonattainment area is located.

4 4. Not applicable.

The extent of New York City’s

nonattainment problem and the nature

of the contributions from upwind States

were considered in determining

whether the values of the metrics

indicate large and/or frequent

contributions for individual upwind

States. Specifically, additional controls

beyond the local and upwind NOX

reductions which are part of the

regional NOX strategy may be needed to

solve New York City’s 1-hour

nonattainment problem. Also, the total

contribution from all upwind States is

large and there is no single State or

small number of States which comprise

this total upwind portion. In this regard,

the contributions to New York City from

some States may not appear to be

individually ‘‘high’’ amounts. However,

(as described below) these

contributions, when considered together

with the contributions from other States

(i.e., the collective contribution)

produce a large total contribution to

nonattainment in New York City.

The EPA evaluated the magnitude,

frequency, and relative amount of

contribution from emissions in

individual upwind States to determine

which States contribute significantly to

1-hour nonattainment in New York City.

The UAM–V and CAMx metrics which

quantify each upwind State’s

contribution to New York City for each

of the three factors are provided in the

Air Quality Modeling TSD and

described below. Examination of the

values for these metrics indicates that

the upwind States can be divided into

three general groups, based on the

magnitude, frequency, and relative

amount of contribution. The first group

contains those upwind States for which

the UAM–V and CAMx metrics all

clearly indicate a significant

contribution to 1-hour nonattainment in

New York City. The second group

contains those States for which the

CAMx and UAM–V metrics are not

quite as consistent, but overall the

metrics indicate a significant

contribution to 1-hour nonattainment in

New York City.49 The third group

contains those States for which the

CAMx and UAM–V metrics clearly

indicate that the impacts do not make a

significant contribution to New York

City.

Group 1 Upwind States:

The CAMx and UAM–V metrics all

clearly indicate that emissions from

Maryland/Washington, DC/Delaware,

Ohio, Pennsylvania, Virginia, and West

Virginia make large and/or frequent

contributions to 1-hour nonattainment

in New York City. For Pennsylvania the

magnitude of contribution, as indicated

by the highest daily average

contribution (CAMx Metric 3), is 25 ppb

and the relative amount of contribution

is 18 percent (CAMx Metric 4). For the

other upwind areas, the magnitude of

the contributions range from 9 ppb to 15

ppb (CAMx Metric 3, highest daily

average contributions) with

contributions in the range of 5 ppb to 10

ppb—from Ohio, Virginia, and West

Virginia (UAM–V Metric 2, maximum

‘‘ppb’’ contribution). In terms of the

frequency of the contribution, 7 percent

to 11 percent of the total number of gridhours >=125 ppb in New York City

receive contributions of 10 ppb from

each of these States (CAMx Metric 1 and

2). Also, the relative amounts of the

contribution are in the range of 6

percent to 8 percent (CAMx Metric 4,

highest single-episode average percent

contribution) and the total contribution

from each of three States (i.e., Ohio,

Virginia, and West Virginia) is large

compared to the total amount of

nonattainment, ranging from 8 percent

to 11 percent (UAM–V Metric 3).

Group 2 Upwind States:

The CAMx and UAM–V metrics are

somewhat less consistent on the extent

of contributions from each of 5 States:

Kentucky, Illinois, Indiana, Michigan,

and North Carolina. None of the metrics

for either model indicate extremely low

or extremely high contributions. Rather,

for these States most of the metrics

indicate relatively high contributions

while a few metrics indicate relatively

low contributions. The rationale used by

EPA for evaluating the contributions

from these States involved comparing

and contrasting each piece of data for

these States on an individual ‘‘upwind

State-by-upwind State’’ basis and as a

group (i.e., for all 5 States, together) in

order to weigh the relative magnitude

and frequency of the contributions for

making a determination of significance.

UAM–V Metrics—For each of these 5

States the ‘‘weakest’’ factor is the

magnitude contribution (UAM–V Metric

2) in that the highest contributions are

in the range of 2 to 5 ppb. The other

UAM–V Metrics, however, indicate that

the contributions from each State are of

a larger frequency and relative amount.

Specifically, four of these States

(Kentucky, Indiana, Illinois, and
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57393

Michigan) each contribute 2 to 5 ppb to

as many as 3 percent to 4 percent of the

exceedences in New York City (UAM–

V Metrics 1 and 2). While North

Carolina contributes to somewhat fewer

exceedences (2 percent), this slight

weakness is out-weighed by the relative

amount of contribution (UAM–V

Metrics 3 and 4) which indicates that

the total contribution from North

Carolina alone is equivalent to 3 percent

of the total ‘‘ppb’’ >=125 ppb and 4

percent of the population-weighted

‘‘ppb’’ >=125 ppb in New York City. For

Indiana, Illinois, and Michigan the

relative amount of contribution (UAM–

V Metrics 3 and 4) is also relatively high

and ranges from 3 percent to 5 percent.

The relative amount of contribution

from Kentucky is somewhat weaker at 2

percent.

CAMx Metrics—For Illinois, all of the

CAMx metrics indicate relatively large

and/or frequent contributions, as

described below. For Kentucky, Indiana,

Michigan, and North Carolina the

magnitude of contribution is large, as

indicated by the maximum contribution

which ranges from 6 ppb (Indiana) to 11

ppb (North Carolina). Also, the highest

daily average contribution from

Kentucky, Michigan, and North Carolina

are all in the range of 5 ppb to 7 ppb.

In terms of the frequency of

contribution, Indiana and North

Carolina contribute in the range of 5 ppb

to 10 ppb to 3 percent and 6 percent of

the exceedences, respectively, in New

York City. For Kentucky, Indiana,

Michigan, and North Carolina the

relative amounts of contribution is

somewhat mixed in that the 4-episode

average percent contribution is only 1

percent, but the highest single-episode

average percent contributions are higher

at 2 percent from both Indiana and

North Carolina, 3 percent from

Kentucky, and 4 percent from Michigan

(CAMx Metric 4).

Overall contributions considering

UAM–V and CAMx Metrics—

Considering the CAMx and UAM–V

metrics, as described below, the

majority of the contribution factors

indicate that, overall, each of the Group

2 States contributes significantly to 1-

hour nonattainment in New York City.

Kentucky—

Metrics indicating relatively high

and/or frequent contributions:

—Magnitude of Contribution: the

maximum contribution from CAMx is

9 ppb (CAMx Metric 2) and highest

daily average contribution is 7 ppb

(CAMx Metric 3);

—Frequency of Contribution: 4 percent

of the exceedences receive

contributions of more than 2 ppb

(UAM–V Metrics 1 and 2); and

—Relative Amount of Contribution: the

highest single-episode average

contribution is 3 percent (CAMx

Metric 4).

Metrics indicating relatively low and/

or infrequent contributions:

—Magnitude of Contribution: the

maximum contribution from UAM–V

is 2 ppb; and

—Relative Amount of Contribution: the

4-episode average percent

contribution is 1 percent (CAMx

Metric 4).

Indiana—

Metrics indicating relatively high

and/or frequent contributions:

—Magnitude of Contribution: the

maximum ‘‘ppb’’ contribution is 6

ppb (CAMx Metric 2);

—Frequency of Contribution: 4 percent

of the exceedences receive

contributions of more than 2 ppb

(UAM–V Metrics 1 and 2) ; and

—Relative Amount of Contribution: the

total ‘‘ppb’’ contribution is equivalent

to 3 percent of total amount of

nonattainment (UAM–V Metric 3).

Metrics indicating relatively low and/

or infrequent contributions:

—Magnitude of Contribution: the

maximum contribution from is 2 ppb

(UAM–V Metric 2); and

—Relative Amount of Contribution: the

4-episode average percent

contribution is 1 percent (CAMx

Metric 4).

Illinois—

Metrics indicating relatively high

and/or frequent contributions:

—Magnitude of Contribution: the

maximum contribution is 8 ppb

(CAMx Metric 2); the highest daily

average contribution is 6 ppb;

—Frequency of Contribution: 3 percent

of the exceedences receive

contributions of more than 2 ppb; and

—Relative Amount of Contribution: the

highest single-episode average

contribution is 3 percent (CAMx

Metric 4); the total ‘‘ppb’’ contribution

is equivalent to 3 percent of total

amount of nonattainment.

Metrics indicating relatively low and/

or infrequent contributions:

—Magnitude of Contribution: the

maximum contribution from UAM–V

is 2 ppb.

Michigan—

Metrics indicating relatively high

and/or frequent contributions:

—Magnitude of Contribution: the

maximum contribution is 7 ppb

(CAMx Metric 2); the highest daily

average contribution is 5 ppb (CAMx

Metric 3);

—Frequency of Contribution: 3 percent

of the exceedences receive

contributions of more than 2 ppb

(UAM–V Metrics 1 and 2); and

—Relative Amount of Contribution: the

highest single-episode average

contribution is 4 percent (CAMx

Metric 4); the total ‘‘ppb’’ contribution

is equivalent to 3 percent of the total

amount of nonattainment.

Metrics indicating relatively low and/

or infrequent contributions:

—Magnitude of Contribution: the

maximum contribution from UAM–V

is 2 ppb

—Frequency of Contribution: 1 percent

of the exceedences receive

contributions of 5 ppb or more (CAMx

Metrics 1 and 2); and

—Relative Amount of Contribution: the

4-episode average percent

contribution is 1 percent (CAMx

Metric 4).

North Carolina—

Metrics indicating relatively high

and/or frequent contributions:

—Magnitude of Contribution: the

maximum contribution is 11 ppb

(CAMx Metric 2); the highest daily

average contribution is 6 ppb (CAMx

Metric 3);

—Frequency of Contribution: 6 percent

of exceedences receive contributions

of 5 ppb or more (CAMx Metrics 1

and 2); and

—Relative Amount of Contribution: the

total ‘‘ppb’’ contribution is equivalent

to 3 percent of total amount of

nonattainment.

Metrics indicating relatively low and/

or infrequent contributions:

—Relative Amount of Contribution: the

4-episode average percent

contribution is 1 percent (CAMx

Metric 4).

Group 3 Upwind States: The CAMx

and UAM–V metrics clearly indicate

that the emissions from the following

States do not make large and/or frequent

contributions to 1-hour nonattainment

in New York City: Alabama, Georgia,

Massachusetts, Missouri, South

Carolina, Tennessee, and Wisconsin.

The rationale for this conclusion is as

follows:

—Magnitude of Contribution: all of

these upwind States individually

contribute less than 2 ppb to 1-hour

daily maximum exceedences in New

York City (UAM–V Metric 2); the

highest daily average contribution

was 1 ppb or less from Alabama,

Georgia, and Massachusetts, and 2
57394 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

ppb from South Carolina, Tennessee,

and Wisconsin (CAMx Metric 3); and

—Relative Amount of Contribution: the

4-episode average contributions from

Alabama, Georgia, Massachusetts,

South Carolina, and Wisconsin are

less than 1 percent (CAMx Metric 4);

the total contributions from Missouri

and Tennessee are each equivalent to

1 percent of the total amount of

nonattainment in New York City

(UAM–V Metric 3).

Based on the preceding evaluation,

EPA believes that emissions in each of

the following twelve jurisdictions

contribute significantly to 1-hour

nonattainment in the New York City

nonattainment area: the District of

Columbia, Delaware, Illinois, Indiana,

Kentucky, Maryland, Michigan, North

Carolina, Ohio, Pennsylvania, Virginia,

and West Virginia.

b. States Which Contain Sources That

Significantly Contribute to Downwind

Nonattainment. The results of EPA’s

assessment of the State-by-State UAM–

V and CAMx modeling confirms the

findings based on subregional modeling

that the 23 jurisdictions contribute large

and/or frequent amounts to downwind

nonattainment under both the 1-hour

and 8-hour NAAQS and forms an

independent basis for those findings.

The specific upwind States which

significantly contribute to

nonattainment in specific downwind

States are listed in Tables II–4 and II–

5 for the 1-hour NAAQS and Table II–

6 and Table II–7 for the 8-hour NAAQS.

The information on the 1-hour

contribution linkages are presented by

upwind State in Table II–4 and by

downwind State in Table II–5. In Table

II–4 the upwind States are each listed in

the first column and the downwind

States to which each upwind State

contributes significantly are listed in the

second column. In Table II–5, the same

information is presented by downwind

State. In this table, each downwind

State is listed in the first column and

the upwind States that contribute to that

downwind State are listed in the second

column. The 8-hour contribution

linkages are presented by upwind State

in Table II–6 and by downwind State in

Table II–7.

TABLE II–4.—DOWNWIND STATES FOR WHICH UPWIND STATES CONTAIN SOURCES THAT CONTRIBUTE SIGNIFICANTLY TO

1-HR NONATTAINMENT 1

Upwind state Downwind states

Alabama .............................................................. GA, IL*, IN*, MI*, TN, WI*.

Connecticut ......................................................... ME, MA, NH.

Delaware ............................................................. CT, ME, MA, NH*, NJ, NY, PA, RI, VA.

District of Columbia ............................................. CT, ME, MA, NH*, NJ, NY, PA, RI, VA.

Georgia ............................................................... AL, TN.

Illinois .................................................................. CT*, IN, MD, NJ*, NY, MI, MO, WI*.

Indiana ................................................................ CT*, DE*, DC*, IL*, KY, MD, NJ*, NY, MI, OH, VA*, WI*.

Kentucky ............................................................. AL, CT*, DC*, GA, IL*, IN, MD, MI*, NJ, NY, MO, OH, VA, WI*.

Maryland ............................................................. CT, ME, MA, NH*, NJ, NY, PA, RI, VA.

Massachusetts .................................................... ME, NH.

Michigan .............................................................. CT, DC*, MD, NJ, NY, VA*.

Missouri ............................................................... IL, IN, MI, WI*.

New Jersey ......................................................... CT, ME, MA, NH, NY, PA, RI.

New York ............................................................ CT, ME, MA, NH, NJ, RI.

North Carolina ..................................................... CT*, DC*, GA, KY, MD, NJ, NY, OH, PA, VA*.

Ohio ..................................................................... CT, DE, DC*, KY, MD, MA, NH*, NJ, NY, PA, RI, VA.

Pennsylvania ....................................................... CT, DE, DC, ME, MD, MA, NH, NJ, NY, RI, VA.

Rhode Island ....................................................... ME, MA, NH.

South Carolina .................................................... AL, GA, TN.

Tennessee .......................................................... AL, GA, IL*, IN, KY, MI*, OH, WI*.

Virginia ................................................................ CT, DE, DC, KY*, MD, MA, NH*, NJ, NY, PA, RI.

West Virginia ....................................................... CT, DE, DC, MD, MA, NJ, NY, PA, RI, VA.

Wisconsin ............................................................ IL*, IN*, MI* .

1States marked with an asterisk (*) are included because they are part of an interstate nonattainment area that receives a contribution from

the upwind State. New Hampshire is included because it is part of the combined Boston/Portsmouth area; Connecticut and New Jersey are included because they are part of the New York City area; Kentucky is included because it is part of the Cincinnati area; Delaware is included because it is part of the Philadelphia area; Illinois is included because it is part of the St. Louis area; Illinois, Indiana, Michigan, and Wisconsin are

included because they are part of the Lake Michigan area; and Maryland, Virginia, and the District of Columbia are included because they are

part of the Washington, DC area.

TABLE II–5.—UPWIND STATES THAT CONTAIN SOURCES THAT CONTRIBUTE SIGNIFICANTLY TO 1-HR NONATTAINMENT IN

DOWNWIND STATES 1

Downwind state Upwind states

Alabama .............................................................. GA, KY, SC, TN.

Connecticut ......................................................... DE, DC, IL*, IN*, KY*, MD, MI*, NJ, NY, NC*, OH, PA, VA, WV.

Delaware ............................................................. IN*, OH, PA, VA, WV.

District of Columbia ............................................. IN*, KY*, MI*, NC*, OH*, PA, VA, WV.

Georgia ............................................................... AL, KY, NC, SC, TN.

Illinois .................................................................. AL*, IN*, KY*, MO, TN*, WI*.

Indiana ................................................................ AL*, IL, KY, MO, TN, WI*.

Kentucky ............................................................. IN, NC, OH, TN, VA*.

Maine .................................................................. CT, DE, DC, MD, MA, NJ, NY, PA, RI.

Maryland ............................................................. IL, IN, KY, MI, NC, OH, PA, VA, WV.

Massachusetts .................................................... CT, DE, DC, MD, NJ, NY, OH, PA, RI, VA, WV.

Michigan .............................................................. AL*, IL, IN, KY*, MO, TN*, WI*.

Missouri ............................................................... IL, KY.
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57395

TABLE II–5.—UPWIND STATES THAT CONTAIN SOURCES THAT CONTRIBUTE SIGNIFICANTLY TO 1-HR NONATTAINMENT IN

DOWNWIND STATES 1—Continued

Downwind state Upwind states

New Hampshire .................................................. CT, DC*, DE*, MD*, MA, NJ, NY, OH*, PA, RI, VA*.

New Jersey ......................................................... DE, DC, IL*, IN*, KY, MD, MI, NY, NC, OH, PA, VA, WV.

New York ............................................................ DE, DC, IL, IN, KY, MD, MI, NJ, NC, OH, PA, VA, WV.

Ohio ..................................................................... IN, KY, TN, NC.

Pennsylvania ....................................................... DE, DC, MD, NJ, NC, OH, VA, WV.

Rhode Island ....................................................... DE, DC, MD, NJ, NY, OH, PA, VA, WV.

Tennessee .......................................................... AL, GA, SC.

Virginia ................................................................ DE, DC, IN*, KY, MD, MI*, NC*, OH, PA, WV.

Wisconsin ............................................................ AL*, IL*, IN*, KY*, MO*, TN* .

1 Upwind States marked with an asterisk (*) are considered to significantly contribute to the downwind State because they contribute to an

interstate nonattainment area that includes part of the downwind State. New Hampshire is included in the Boston/Portsmouth area; Connecticut

and New Jersey are included in the New York City area; Kentucky is included in the Cincinnati area; Delaware is included in the Philadelphia

area; Illinois is included in the St. Louis area; Illinois, Indiana, Michigan, and Wisconsin are included in the Lake Michigan area; and Maryland

and Virginia are included in the Washington, DC area.

TABLE II–6.—DOWNWIND STATES TO WHICH SOURCES IN UPWIND STATES CONTRIBUTE SIGNIFICANTLY FOR THE 8-HOUR

STANDARD

Upwind state Downwind states

Alabama .............................................................. GA, IL, IN, KY, MI, MO, NC, OH, PA, SC, TN, VA.

Connecticut ......................................................... ME, MA, NH, RI.

Delaware ............................................................. CT, ME, MA, NH, NJ, NY, PA, RI, VA.

District of Columbia ............................................. CT, ME, MD, MA, NH, NJ, NY, PA, RI, VA.

Georgia ............................................................... AL, IL, IN, KY, MI, MO, NC, SC, TN, VA.

Illinois .................................................................. AL, CT, DC, DE, IN, KY, MD, MI, MO, NJ, NY, OH, PA, RI, TN, WV, WI.

Indiana ................................................................ DE, IL, KY, MD, MI, MO, NJ, NY, OH, PA, TN, VA, WV, WI.

Kentucky ............................................................. AL, DC, DE, GA, IL, IN, MD, MI, MO, NJ, NY, NC, OH, PA, SC, TN, VA, WV, WI.

Maryland ............................................................. CT, DE, DC, ME, MA, NH, NJ, NY, PA, RI, VA.

Massachusetts .................................................... ME, NH

Michigan .............................................................. CT, DC, DE, MD, MA, NJ, NY, OH, PA, WV.

Missouri ............................................................... IL, IN, KY, MI, OH, PA, TN, WI.

New Jersey ......................................................... CT, ME, MA, NH, NY, PA, RI.

New York ............................................................ CT, ME, MA, NH, NJ, PA, RI.

North Carolina ..................................................... AL, CT, DE, GA, IN, KY, ME, MD, MA, NJ, NY, OH, PA, RI, SC, TN, VA, WV.

Ohio ..................................................................... CT, DC, DE, IN, KY, MD, MA, MI, NJ, NY, NC, PA, RI, TN, VA, WV.

Pennsylvania ....................................................... CT, DC, DE, ME, MD, MA, NH, NJ, NY, OH, RI, VA.

Rhode Island ....................................................... ME, MA, NH.

South Carolina .................................................... AL, GA, IN, KY, NC, TN, VA.

Tennessee .......................................................... AL, DC, DE, GA, IL, IN, KY, MD, MI, MO, NC, OH, PA, SC, VA, WV, WI.

Virginia ................................................................ CT, DE, DC, ME, MD, MA, NJ, NY, NC, OH, PA, RI, SC, WV.

West Virginia ....................................................... CT, DC, DE, IN, KY, MD, MA, NJ, NY, NC, OH, PA, RI, SC, TN, VA.

Wisconsin ............................................................ MI.

TABLE II–7.—UPWIND STATES THAT CONTAIN SOURCES THAT CONTRIBUTE SIGNIFICANTLY TO 8-HOUR NONATTAINMENT IN

DOWNWIND STATES.

Downwind state Upwind states

Alabama .............................................................. GA, IL, KY, NC, SC, TN.

Connecticut ......................................................... DE, DC, IL, MD, MI, NJ, NY, NC, OH, PA, VA, WV.

District of Columbia ............................................. IL, KY, MD, MI, OH, PA, TN, VA, WV.

Delaware ............................................................. IL, IN, KY, MI, NC, OH, PA, TN, VA, WV.

Georgia ............................................................... AL, KY, NC, SC, TN.

Illinois .................................................................. AL, GA, IN, KY, MO, TN.

Indiana ................................................................ AL, GA, IL, KY, MO, NC, OH, SC, TN, WV.

Kentucky ............................................................. AL, GA, IL, IN, MO, NC, OH, SC, TN, WV.

Maine .................................................................. CT, DE, DC, MD, MA, NJ, NY, NC, PA, RI, VA

Maryland ............................................................. DC, IL, IN, KY, MI, NC, OH, PA, TN, VA, WV.

Massachusetts .................................................... CT, DE, DC, MD, MI, NJ, NY, NC, OH, PA, RI, VA, WV.

Michigan .............................................................. AL, GA, IL, IN, KY, MO, OH, TN, WI.

Missouri ............................................................... AL, GA, IL, IN, KY, TN.

New Hampshire .................................................. CT, DE, DC, MD, MA, NJ, NY, PA, RI.

New Jersey ......................................................... DE, DC, IL, IN, KY, MD, MI, NC, NY, OH, PA, VA, WV.

New York ............................................................ DE, DC, IL, IN, KY, MD, MI, NC, NJ, OH, PA, VA, WV.

North Carolina ..................................................... AL, GA, KY, OH, SC, TN, VA, WV.

Ohio ..................................................................... AL, IL, IN, KY, MI, MO, NC, PA, TN, VA, WV.

Pennsylvania ....................................................... AL, DE, DC, IL, IN, KY, MD, MI, MO, NJ, NY, NC, OH, TN, VA, WV.

Rhode Island ....................................................... CT, DE, DC, IL, MD, NJ, NY, NC, OH, PA, VA, WV.
57396 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

TABLE II–7.—UPWIND STATES THAT CONTAIN SOURCES THAT CONTRIBUTE SIGNIFICANTLY TO 8-HOUR NONATTAINMENT IN

DOWNWIND STATES.—Continued

Downwind state Upwind states

South Carolina .................................................... AL, GA, KY, NC, TN, VA, WV.

Tennessee .......................................................... AL, GA, IL, IN, KY, MO, NC, OH, SC, WV.

Virginia ................................................................ AL, DE, DC, GA, IN, KY, MD, NC, OH, PA, SC, TN, WV.

West Virginia ....................................................... IL, IN, KY, MI, NC, OH, TN, VA.

Wisconsin ............................................................ IL, IN, KY, MO, TN.

c. Examples of Contributions From

Upwind States to Downwind

Nonattainment. A full discussion of

EPA’s analysis supporting the

determination that specific upwind

States contribute significantly to

individual downwind States under the

1-hour and 8-hour NAAQS is provided

in the Air Quality Modeling TSD.

Examples of the types of contributions

which link individual upwind States to

downwind areas are provided below for

the 1-hour NAAQS for the 23 upwind

jurisdictions.

—Alabama’s Contribution to 1-Hour

Nonattainment in Atlanta

Magnitude of Contribution: The

maximum contribution is 39 ppb

(CAMx Metric 2); the highest daily

average contribution is 31 ppb (CAMx

Metric 3).

Frequency of Contribution: Alabama

contributes at least 10 ppb to 12 percent

of the 1-hr exceedences (UAM–V

Metrics 1 and 2).

Relative Amount: The total

contribution from Alabama is equivalent

to 14 percent of the total amount >=125

ppb in Atlanta (UAM–V Metric 3);

Alabama contributes 8 percent of the

total manmade ppb >= 125 ppb in

Atlanta (CAMx Metric 4; 4-episode

average percent contribution).

—Connecticut/Rhode Island’s

Contribution to 1-Hour Nonattainment

in Western Massachusetts

Magnitude of Contribution: The

maximum contribution is 61 ppb

(CAMx Metric 2); the highest daily

average contribution is 50 ppb (CAMx

Metric 3).

Frequency of Contribution:

Connecticut/Rhode Island contribute at

least 10 ppb to 100 percent of the 1-hr

exceedences (CAMx Metrics 1 and 2).

Relative Amount: Connecticut/Rhode

Island contribute 35 percent of the total

manmade ppb >= 125 ppb in Western

Massachusetts (CAMx Metric 4; 4-

episode average percent contribution).

—Georgia’s Contribution to 1-Hour

Nonattainment in Birmingham

Magnitude of Contribution: The

maximum contribution is 51 ppb

(CAMx Metric 2); the highest daily

average contribution is 24 ppb (CAMx

Metric 3).

Frequency of Contribution: Georgia

contributes at least 10 ppb to 11 percent

of the 1-hr exceedences (UAM–V

Metrics 1 and 2).

Relative Amount: The total

contribution from Georgia is equivalent

to 12 percent of the total amount >=125

ppb in Birmingham (UAM–V Metric 3);

Georgia contributes 3 percent of the

total manmade ppb >= 125 ppb in

Birmingham (CAMx Metric 4; 4-episode

average percent contribution).

—Illinois’s Contribution to 1-Hour

Nonattainment in New York City

Magnitude of Contribution: The

maximum contribution is 8 ppb (CAMx

Metric 2); the highest daily average

contribution is 6 ppb (CAMx Metric 3).

Frequency of Contribution: Illinois

contributes at least 5 ppb to 20 percent

of the 1-hr exceedences (CAMx Metrics

1 and 2).

Relative Amount: The total

contribution from Illinois is equivalent

to 3 percent of the total amount >=125

ppb in New York City (UAM–V Metric

3); Illinois contributes 3 percent of the

total manmade ppb >= 125 ppb in New

York City (CAMx Metric 4; single

highest episode percent contribution).

—Indiana’s Contribution to 1-Hour

Nonattainment in Baltimore

Magnitude of Contribution: The

maximum contribution is 8 ppb (CAMx

Metric 2); the highest daily average

contribution is 6 ppb (CAMx Metric 3).

Frequency of Contribution: Indiana

contributes at least 5 ppb to 26 percent

of the 1-hr exceedences (CAMx Metrics

1 and 2).

Relative Amount: The total

contribution from Indiana is equivalent

to 4 percent of the total amount >=125

ppb in Baltimore (UAM–V Metric 3);

Indiana contributes 3 percent of the

total manmade ppb >= 125 ppb in New

York City (CAMx Metric 4; single

highest episode percent contribution).

—Kentucky’s Contribution to 1–Hour

Nonattainment in Baltimore

Magnitude of Contribution: The

maximum contribution is 9 ppb (CAMx

Metric 2); the highest daily average

contribution is 8 ppb (CAMx Metric 3).

Frequency of Contribution: Kentucky

contributes at least 5 ppb to 24 percent

of the 1-hr exceedences (CAMx Metrics

1 and 2).

Relative Amount: The total

contribution from Kentucky is

equivalent to 3 percent of the total

amount >=125 ppb in Baltimore (UAM–

V Metric 3); Kentucky contributes 5

percent of the total manmade ppb >=

125 ppb in Baltimore (CAMx Metric 4;

single highest episode percent

contribution).

—Maryland/District of Columbia/

Delaware’s Contribution to 1-Hour

Nonattainment in New York City

Magnitude of Contribution: The

maximum contribution is 50 ppb

(CAMx Metric 2); the highest daily

average contribution is 15 ppb (CAMx

Metric 3).

Frequency of Contribution: Maryland/

District of Columbia/Delaware

contribute at least 10 ppb to 14 percent

of the 1-hr exceedences and at least 5

ppb to 38 percent of the 1-hr

exceedences (CAMx Metrics 1 and 2).

Relative Amount: Maryland/District

of Columbia/Delaware contribute 5

percent of the total manmade ppb >=

125 ppb in New York City (CAMx

Metric 4; 4-episode average percent

contribution).

—Massachusetts’ Contribution to 1-

Hour Nonattainment in Portland, ME

Magnitude of Contribution: The

maximum contribution is 79 ppb

(CAMx Metric 2); the highest daily

average contribution is 67 ppb (CAMx

Metric 3).

Frequency of Contribution:

Massachusetts contributes at least 10

ppb to 100 percent of the 1-hr

exceedences (UAM–V Metrics 1 and 2).

Relative Amount: The total

contribution from Massachusetts is

equivalent to 100 percent of the total

amount >=125 ppb in Portland, ME
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57397

(UAM–V Metric 3); Massachusetts

contributes 56 percent of the total

manmade ppb >= 125 ppb in Portland,

ME (CAMx Metric 4; 4-episode average

percent contribution).

—Michigan’s Contribution to 1-Hour

Nonattainment in Baltimore

Magnitude of Contribution: The

maximum contribution is 9 ppb (CAMx

Metric 2); the highest daily average

contribution is 8 ppb (CAMx Metric 3).

Frequency of Contribution: Michigan

contributes at least 5 ppb to 7 percent

of the 1-hr exceedences (CAMx Metrics

1 and 2).

Relative Amount: The total

contribution from Michigan is

equivalent to 5 percent of the total

amount >=125 ppb in Baltimore (UAM–

V Metric 3); Michigan contributes 5

percent of the total manmade ppb >=

125 ppb in Baltimore (CAMx Metric 4;

single highest episode percent

contribution).

—Missouri’s Contribution to 1-Hour

Nonattainment over Lake Michigan

Magnitude of Contribution: The

maximum contribution is 19 ppb

(CAMx Metric 2); the highest daily

average contribution is 12 ppb (CAMx

Metric 3).

Frequency of Contribution: Missouri

contributes at least 10 ppb to 66 percent

of the 1-hr exceedences (CAMx Metrics

1 and 2).

Relative Amount: The total

contribution from Missouri is equivalent

to 22 percent of the total amount >=125

ppb over Lake Michigan (UAM–V

Metric 3); Missouri contributes 9

percent of the total manmade ppb >=

125 ppb over Lake Michigan (CAMx

Metric 4; 4-episode average percent

contribution).

—New Jersey’s Contribution to 1-Hour

Nonattainment in Western

Massachusetts

Magnitude of Contribution: The

maximum contribution is 30 ppb

(CAMx Metric 2); the highest daily

average contribution is 23 ppb (CAMx

Metric 3).

Frequency of Contribution: New

Jersey contributes at least 10 ppb to 100

percent of the 1-hr exceedences (CAMx

Metrics 1 and 2).

Relative Amount: New Jersey

contributes 16 percent of the total

manmade ppb >= 125 ppb in Western

Massachusetts (CAMx Metric 4; 4-

episode average percent contribution).

—New York’s Contribution to 1-Hour

Nonattainment in Western

Massachusetts

Magnitude of Contribution: The

maximum contribution is 25 ppb

(CAMx Metric 2); the highest daily

average contribution is 23 ppb (CAMx

Metric 3).

Frequency of Contribution: New York

contributes at least 10 ppb to 100

percent of the 1-hr exceedences (CAMx

Metrics 1 and 2).

Relative Amount: New York

contributes 18 percent of the total

manmade ppb >= 125 ppb in Western

Massachusetts (CAMx Metric 4; 4-

episode average percent contribution).

—North Carolina’s Contribution to 1-

Hour Nonattainment in Philadelphia

Magnitude of Contribution: The

maximum contribution is 10 ppb

(CAMx Metric 2); the highest daily

average contribution is 9 ppb (CAMx

Metric 3).

Frequency of Contribution: North

Carolina contributes at least 2 ppb to 4

percent of the 1-hr exceedences (UAM–

V Metrics 1 and 2).

Relative Amount: The total

contribution from North Carolina is

equivalent to 4 percent of the total

amount >=125 ppb in Philadelphia

(UAM–V Metric 3); North Carolina

contributes 2 percent of the total

manmade ppb >= 125 ppb in

Philadelphia (CAMx Metric 4; single

highest episode percent contribution).

—Ohio’s Contribution to 1-Hour

Nonattainment in Baltimore

Magnitude of Contribution: The

maximum contribution is 13 ppb

(CAMx Metric 2); the highest daily

average contribution is 12 ppb (CAMx

Metric 3).

Frequency of Contribution: Ohio

contributes at least 5 ppb to 51 percent

of the 1-hr exceedences (CAMx Metrics

1 and 2).

Relative Amount: The total

contribution from Ohio is equivalent to

11 percent of the total amount >=125

ppb in Baltimore (UAM–V Metric 3);

Ohio contributes 4 percent of the total

manmade ppb >= 125 ppb in Baltimore

(CAMx Metric 4; 4-episode average

percent contribution).

—Pennsylvania’s Contribution to 1-

Hour Nonattainment in Greater

Connecticut

Magnitude of Contribution: The

maximum contribution is 28 ppb

(CAMx Metric 2); the highest daily

average contribution is 23 ppb (CAMx

Metric 3).

Frequency of Contribution:

Pennsylvania contributes at least 10 ppb

to 60 percent of the 1-hr exceedences

and at least 5 ppb to 98 percent of the

1-hr exceedences (CAMx Metrics 1 and

2).

Relative Amount: Pennsylvania

contributes 10 percent of the total

manmade ppb >= 125 ppb in Greater

Connecticut (CAMx Metric 4; 4-episode

average percent contribution).

—South Carolina’s Contribution to 1-

Hour Nonattainment in Atlanta

Magnitude of Contribution: The

maximum contribution is 24 ppb

(CAMx Metric 2); the highest daily

average contribution is 23 ppb (CAMx

Metric 3).

Frequency of Contribution: South

Carolina contributes at least 5 ppb to 6

percent of the 1-hr exceedences (UAM–

V Metrics 1 and 2).

Relative Amount: The total

contribution from South Carolina is

equivalent to 4 percent of the total

amount >=125 ppb in Atlanta (UAM–V

Metric 3); South Carolina contributes 2

percent of the total manmade ppb >=

125 ppb in Atlanta (CAMx Metric 4;

single highest episode percent

contribution).

—Tennessee’s Contribution to 1–Hour

Nonattainment Over Lake Michigan

Magnitude of Contribution: The

maximum contribution is 12 ppb

(CAMx Metric 2); the highest daily

average contribution is 11 ppb (CAMx

Metric 3).

Frequency of Contribution: Tennessee

contributes at least 5 ppb to 14 percent

of the 1-hr exceedences (UAM–V

Metrics 1 and 2).

Relative Amount: The total

contribution from Tennessee is

equivalent to 6 percent of the total

amount >=125 ppb over Lake Michigan

(UAM–V Metric 3); Tennessee

contributes 10 percent of the total

manmade ppb >= 125 ppb over Lake

Michigan (CAMx Metric 4; single

highest episode percent contribution).

—Virginia’s Contribution to 1-Hour

Nonattainment in New York City

Magnitude of Contribution: The

maximum contribution is 25 ppb

(CAMx Metric 2); the highest daily

average contribution is 11 ppb (CAMx

Metric 3).

Frequency of Contribution: Virginia

contributes at least 10 ppb to 11 percent

of the 1-hr exceedences and at least 5

ppb to 36 percent of the 1-hr

exceedences (CAMx Metrics 1 and 2).

Relative Amount: The total

contribution from Virginia is equivalent

to 11 percent of the total amount >=125

ppb in New York City (UAM–V Metric

3); Virginia contributes 4 percent of the
57398 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

50See ‘‘Notice of Availability’’ 63 FR 45032

(August 24, 1998).

total manmade ppb >= 125 ppb in New

York City (CAMx Metric 4; 4-episode

average percent contribution).

—West Virginia’s Contribution to 1-

Hour Nonattainment in New York City

Magnitude of Contribution: The

maximum contribution is 14 ppb

(CAMx Metric 2); the highest daily

average contribution is 10 ppb (CAMx

Metric 3).

Frequency of Contribution: West

Virginia contributes at least 5 ppb to 9

percent of the 1-hr exceedences and at

least 2 ppb to 28 percent of the 1-hr

exceedences (UAM–V Metrics 1 and 2).

Relative Amount: The total

contribution from West Virginia is

equivalent to 9 percent of the total

amount >=125 ppb in New York City

(UAM–V Metric 3); West Virginia

contributes 7 percent of the total

manmade ppb >= 125 ppb in New York

City (CAMx Metric 4; single highest

episode percent contribution).

—Wisconsin’s Contribution to 1–Hour

Nonattainment Over Lake Michigan

Magnitude of Contribution: The

maximum contribution is 43 ppb

(CAMx Metric 2); the highest daily

average contribution is 8 ppb (CAMx

Metric 3).

Frequency of Contribution: Wisconsin

contributes at least 10 ppb to 11 percent

of the 1-hr exceedences (CAMx Metrics

1 and 2).

Relative Amount: Wisconsin

contributes 4 percent of the total

manmade ppb >= 125 ppb over Lake

Michigan (CAMx Metric 4; 4-episode

average percent contribution).

d. Conclusions From Air Quality

Evaluation of Downwind Contributions.

As indicated above, EPA is following a

multi-step approach for determining

whether emissions from an upwind

State significantly contribute to

nonattainment downwind. The first step

involves an air quality evaluation to

determine whether the air quality

factors, and particularly the extent of

the downwind contributions from

emissions in the upwind State, indicate

that those contributions are large and/or

frequent enough to be of concern under

the 1-hour and/or 8-hour NAAQS. The

second step, as described below,

employs a cost-effectiveness analysis to

determine which of the upwind

emissions may be eliminated through

highly cost-effective controls. Any

emissions that may be so eliminated are

considered to be emissions that

significantly contribute to

nonattainment downwind. Finally, to

confirm that the emissions considered

to significantly contribute, taken as a

whole, have a meaningful impact on

nonattainment in downwind areas, EPA

modeled the air quality effects of

eliminating that amount of emissions

(see Section IV, Air Quality Assessment,

below).

The EPA’s conclusions from the first

step in this process, the air quality

evaluation, is that emissions from

sources in each of the 23 jurisdictions

listed below make a significant

contribution to nonattainment

downwind for both the 1-hour and 8-

hour NAAQS and interfere with

maintenance of the 8-hour NAAQS.

This determination was based on two

independent sets of analyses, each of

which EPA believes provides an

independent basis for these conclusions.

These two independent analyses are (1)

subregional modeling using UAM–V,

and (2) State-by-State modeling using

CAMx and UAM–V. For the subregional

modeling, EPA examined the frequency

and magnitude of the impacts from each

subregion along with State emissions

data and other air quality information to

evaluate the contributions from upwind

States to nonattainment in downwind

areas. For the UAM–V and CAMx Stateby-State techniques, a number of

measures of ozone contribution, or

metrics, were used to assess, from

several perspectives, the air quality

effect of contributions from sources in

different upwind States.

The EPA weighed the results of its

analysis of these several air quality

metrics to determine which upwind

States contain sources whose emissions

contribute significantly to downwind

nonattainment or maintenance

problems. By examining the results of

several air quality metrics, EPA assured

that no one metric determined whether

a State contains sources whose

emissions contribute to downwind air

quality problems. Rather, the

determination of whether an upwind

State contained sources whose

emissions contribute significantly to a

downwind nonattainment problem was

based on the extent of the contributions

reflected by multiple metrics. The EPA

concluded that each set of modeling

(i.e., subregional and State-by-State)

when considered independently under

EPA’s weight-of-evidence approach

provides a sound technical basis for

finding that NOX emissions from

sources in the following 23 jurisdictions

make a significant contribution to

nonattainment of the 1-hour and 8-hour

NAAQS in, or interfere with

maintenance of the 8-hour NAAQS by,

one or more downwind States:

Alabama

Connecticut

Delaware

District of Columbia

Georgia

Illinois

Indiana

Kentucky

Maryland

Massachusetts

Michigan

Missouri

New Jersey

New York

North Carolina

Ohio

Pennsylvania

Rhode Island

South Carolina

Tennessee

Virginia

West Virginia

Wisconsin

The remaining 15 OTAG States not

covered by this final rule are discussed

below.

5. States Not Covered by This

Rulemaking

In Section VI of the NPR, EPA

proposed to find that emissions from

sources in the following 15 States in the

OTAG region do not significantly

contribute to downwind nonattainment

under the 1-hour or 8-hour ozone

NAAQS, or interfere with maintenance

under the 8-hour NAAQS: Arkansas,

Florida, Iowa, Kansas, Louisiana, Maine,

Minnesota, Mississippi, North Dakota,

Nebraska, New Hampshire, Oklahoma,

South Dakota, Texas, Vermont (62 FR

60369). The EPA received comments on

this section of the NPR and has recently

conducted some additional CAMx

analyses.50 The CAMx modeling

suggested that further analysis using

UAM–V State-by-State modeling would

be warranted in order to have a set of

information comparable to that for other

States that are subject to this rule. In

today’s rulemaking, EPA is taking no

action on whether emissions from

sources in these 15 States do or do not

contribute significantly to downwind

nonattainment, or interfere with

maintenance downwind, under either

NAAQS. Thus, by today’s rulemaking,

EPA is not requiring these 15 States to

submit SIP revisions providing for NOX

emissions controls to meet a statewide

NOX emissions budget; nor is EPA

determining that these States will not be

required to make these SIP submissions

in the future. The EPA is continuing to

review available information on the

downwind impacts of these States,

including comments submitted on the

NPR. In addition, EPA plans to conduct

State-by-State modeling to determine

whether a SIP revision under section

110(a)(2)(D)(i)(I) should be required

from any of these States in the future.
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57399

51OTAG Recommendation: Utility NOX Controls,

approved by the Policy Group, June 3, 1997.

The EPA intends to begin this modeling

in the fall of 1998.

As discussed in the NPR (62 FR 60318

at 60370), EPA reiterates that these 15

States may need to cooperate and

coordinate SIP development activities

with other States that are subject to

today’s action. Also, States with

interstate nonattainment areas for the 1-

hour standard and/or the new 8-hour

standard should cooperate in reducing

emissions to mitigate local-scale

interstate transport problems (e.g.,

transport from one State in a multi-state

urban nonattainment area to another

State in that area) to provide for

attainment in the nonattainment area as

a whole. The EPA encourages the 15

States to conduct additional analyses on

ozone transport recommended by the

OTAG Policy Group, which indicated

that these States, ‘‘* * * will, in

cooperation with EPA, periodically

review their emissions, and the impact

of increases, on downwind

nonattainment areas and, as

appropriate, take steps necessary to

reduce such impacts including

appropriate control measures.’’ 51

Comment: A number of commenters

supported the proposal to exclude the

proposed States, either in general or for

specific States. Others opposed the

proposal in general, or for specific

States.

Response: Because EPA is taking no

action on the 15 States at this time, EPA

will not respond to comments

concerning these States at this time. As

discussed above, EPA intends to

continue to review ambient air quality

data, air quality modeling results, and

other technical information on the

downwind contribution from all States

not found to be significant contributors

in today’s action.

Comment: Several commenters stated

that if EPA revisits which States should

be included in the rulemaking, EPA

must reopen the public comment

period.

Response: The EPA agrees. Because

today’s action does not propose a

change from the NPR concerning which

States should be covered, no new

comment period is needed at this time.

As EPA noted in the NPR, if results from

additional modeling and technical

analyses indicate that States other than

the 22 States (and the District of

Columbia) that are the subject of today’s

action should be required to submit a

SIP revision under section

110(a)(2)(D)(i)(I), EPA will publish a

new NPR as to any such States and

provide an additional comment period.

As also stated in the NPR, in 2007, EPA

will reassess transport in the full OTAG

region to evaluate the effectiveness of

the regional NOX measures and the

need, if any, for additional regional

controls.

D. Cost Effectiveness of Emissions

Reductions

As discussed above, in today’s action,

EPA considers control costs in

determining whether, and the extent to

which, upwind emissions contribute

significantly to nonattainment, or

interfere with maintenance downwind.

The EPA considers cost factors in

conjunction with other factors generally

related to levels of emissions.

1. Sources Included In the CostEffectiveness Determination

This subsection describes the

rationale used to determine the cost

effectiveness of emissions reductions

measures. The EPA evaluates the

relative costs of the available control

measures using average cost

effectiveness, measured as dollars per

ton of NOX reduced relative to a

baseline, to identify those emissions

reductions that are ‘‘highly costeffective.’’ In performing this

evaluation, EPA considers the cost

savings of a regionwide NOX emissions

trading system for large electricity

generating boilers and turbines (i.e.,

boilers and turbines serving a generator

larger than 25 MWe). As described in

this section, EPA has determined that

these emissions reductions are highly

cost effective on a regionwide basis.

To assure equity among the various

source categories and the industries

they represent, EPA considered the cost

effectiveness of controls for each source

category separately throughout the SIP

call region. Sources are combined into

a common source category if they serve

the same general industry (e.g., boilers

and turbines that are used by the

electricity generation industry are

combined in the same category). In

general, this means that the sources in

the same source category share the same

six-digit source code classification

(SCC). One exception is in the case of

boilers and turbines which are

combined and then separated into (1) a

category of boilers and turbines serving

generators that produce electricity for

sale to the grid; or (2) a category of

boilers and turbines that exclusively

generate steam and/or mechanical work

(e.g., provide energy to an industrial

pump), or produce electricity primarily

for internal use and not for sale. The

EPA believes that this categorization

better reflects the industrial sectors

served.

For each source category, the required

emission levels (in tons per ozone

season) were determined based on the

application of NOX controls that achieve

the greatest feasible emissions reduction

while still falling within a cost-per-tonreduced range that EPA considers to be

highly cost-effective (hereinafter also

referred to as ‘‘highly cost-effective’’

measures). Marginal or incremental

costs of control are additional costeffective measures that may provide

important information about

alternatives. In particular, incremental

cost-effectiveness helps to identify

whether a more stringent control option

imposes much higher costs relative to

the average cost per ton for further

control. The use of an average costeffectiveness measure may not fully

reveal costly incremental requirements

where control options achieve large

reductions in emissions (relative to the

baseline).

In this rulemaking, EPA has chosen to

focus on an average cost-effectiveness

measure in identifying highly costeffective control options for several

reasons. Since EPA’s determination for

the core group of sources is based on the

adoption of a broad-based trading

program, average cost-effectiveness

serves as an adequate measure across

sources because sources with high

marginal costs will be able to take

advantage of this program to lower their

costs. In addition, average costeffectiveness estimates are readily

available for other recently adopted

NOX control measures.

The EPA examined a representative

sample of potentially available controls.

NOX controls for this rulemaking were

considered highly cost-effective for the

purposes of reducing ozone transport to

the extent they achieve the greatest

feasible emissions reduction but still

cost no more than $2,000 per ton of

ozone season NOX emissions removed

(in 1990 dollars), on average, for each

source category. The discussion below

further describes the basis for this cost

amount and the techniques used for

each category. Many may consider

certain controls that cost more than

$2,000 per ton of NOX reduced to be

reasonably cost-effective in reducing

ozone transport or in achieving

attainment with the ozone NAAQS in

specific nonattainment areas; however,

EPA has determined to focus today’s

rulemaking on only highly cost-effective

reductions. In the future, as EPA

continues to consider the impact of

ozone transport and the most effective

ways to assure downwind attainment,

EPA may reconsider whether State NOX

budget levels should be lowered to

reflect application of additional controls
57400 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

that, although more expensive, are

nevertheless cost-effective. In addition,

as discussed below, in determining

whether to assume reductions from

source categories with only a few

sources or relatively small emissions,

EPA considered administrative

efficiency in developing conclusions

about whether to assume emissions

reductions for these sources.

In determining the cost of NOX

reductions by large electricity

generating units (EGUs), EPA assumed

an emissions trading system. As

discussed in Section IV below, EPA

evaluated and compared the likely air

quality impacts of this rulemaking with

and without a regionwide NOX

emissions trading system for electricity

generating sources. This analysis shows

that a regionwide trading program

causes no significant adverse air quality

impacts. Because such a program would

result in significant cost savings, EPA’s

cost-effectiveness determination for

large electricity generating boilers and

turbines assumes that each State will

adopt the lowest cost approach, i.e., the

States will elect to include these sources

in a regionwide NOX emissions trading

program. However, States retain the

option of choosing other, perhaps more

expensive, approaches to achieving the

necessary reductions. For non-EGU

sources in the core group of the trading

program, EPA used a least cost method

which is equivalent to an assumption of

an intrastate trading program. Inclusion

of these sources in a regionwide trading

program would provide further cost

savings. For other source categories for

which EPA identified highly costeffective controls (i.e., internal

combustion engines and cement

manufacturing), EPA assumed sourcespecific controls. However, a State may

choose to include such categories in the

trading program and realize further cost

savings.

For the purposes of this rulemaking,

EPA considers the following sizes of

point sources to be large: (1) electricity

generating boilers and turbines serving

a generator greater than 25 MWe; or (2)

other point sources with a heat input

greater than 250 mmBtu/hr or which

emit more than one ton of NOX per

average summer day.

In the NPR, EPA based the costeffectiveness determination on NOX

emissions controls that are available and

of comparable cost to other recently

undertaken or planned NOX measures.

Table 1 provides a reference list of

measures that EPA and States have

recently undertaken to reduce NOX and

their average annual costs per ton of

NOX reduced. Most of these measures

fall below $2,000 per ton. With few

exceptions, the average costeffectiveness of these measures is

representative of the average costeffectiveness of the types of controls

EPA and States have needed to adopt

most recently because their previous

planning efforts have already taken

advantage of opportunities for even

cheaper controls. The EPA believes that

the cost-effectiveness of measures that

EPA or States have adopted, or

proposed to adopt, forms a good

reference point for determining which

of the available additional NOX control

measures can most easily be

implemented by upwind States whose

emissions impact downwind

nonattainment problems.

TABLE 1.—AVERAGE COST-EFFECTIVENESS OF NOX CONTROL MEASURES RECENTLY UNDERTAKEN

[1990 dollars]

Control measure Cost per ton of

NOX Removed

NOX RACT ......................................................................................................................................................................................... 150–1,300

Phase II Reformulated Gasoline ........................................................................................................................................................ 52 4,100

State Implementation of the Ozone Transport Commission Memorandum of Understanding ......................................................... 950–1,600

New Source Performance Standards for Fossil Steam Electric Generation Units ........................................................................... 1,290

New Source Performance Standards for Industrial Boilers ............................................................................................................... 1,790

52Average cost representing the midpoint of $2,180 to $6,000 per ton. This cost represents the projected additional cost of complying with the

Phase II RFG NOX standards, beyond the cost of complying with the other standards for Phase II RFG.

The Federal Phase II RFG costs

presented in Table 1 are not strictly

comparable to the other costs cited in

the table. Federal Phase II RFG will

provide large VOC reductions in

addition to NOX reductions. Federal

RFG is required in nine cities with the

nation’s worst ozone nonattainment

problems; other nonattainment areas

have chosen to opt into the program as

part of their attainment strategy. The

mandated areas and those areas in the

OTAG region that have chosen to opt

into the program are areas where

significant local reductions in ozone

precursors are needed; such areas may

value RFG’s NOX and VOC reductions

differently for their local ozone benefits

than they would value NOX reductions

from RFG or other programs for ozone

transport benefits.

Commenters on the proposal

generally agreed with basing the costeffectiveness determination on the cost

effectiveness of other recently

undertaken measures. Therefore, EPA

has considered controls with an average

cost-effectiveness less than $2,000 per

ton of NOX removed to be highly cost

effective and has calculated the amounts

of emissions that States must prohibit

based on application of these controls.

Some commenters believed that a more

appropriate measure of cost

effectiveness was incremental—instead

of average—dollars per ton of NOX

removed. Other commenters believed

that a more appropriate measure was

dollars per ppb of ozone removed from

a nonattainment area. The EPA

continues to depend on regionwide

average dollars per ton of NOX removed

when evaluating what control measures

are highly cost-effective for the purposes

of this rulemaking.

Table 2 summarizes the control

options investigated for each source

category and the resulting average,

regionwide cost effectiveness.
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57401

55For reasons explained in Section V., below,

EPA has determined that May 1, 2003 is the earliest

practicable date for achieving the level of emissions

reductions EPA selected, and therefore is the

appropriate date for achieving these reductions in

light of the CAA’s attainment date requirements.

TABLE 2.—AVERAGE COST EFFECTIVENESS OF OPTIONS ANALYZED 53

[1990 dollars in 2007]

Source category

Average Cost-effectiveness ($/ozone season ton) for each

control option

Boilers and Turbines Generating Electricity .......................................................... 0.20 lb/mmBtu ...... 0.15 lb/mmBtu ...... 0.12 lb/mmBtu.

$1,263 ................... $1,468 ................... $1,760.

Boilers and Turbines not Generating Electricity .................................................... 50% reduction ....... 60% reduction ....... 70% reduction.

$1,235 ................... $1,467 ................... $2,140.

Other Stationary Sources 54 ................................................................................... $3,000/ton maximum per source.$4,000/ton maximum per source.$5,000/ton maximum per source.

Cement Manufacturing ........................................................................................... $1,458 ................... $1,458 ................... $1,458

Glass Manufacturing .............................................................................................. $2,020 ................... $2,339 ................... $4,758.

Incinerators ............................................................................................................ $2,118 ................... $2,118 ................... $2,118.

Internal Combustion Engines ................................................................................. $1,213 ................... $1,213 ................... $1,215.

Process Heaters .................................................................................................... $2,860 ................... $2,896 ................... $2,896.

53The cost-effectiveness values in Table 2 are regionwide averages. The cost-effectiveness values represent reductions beyond those required by Title IV or Title I RACT, where applicable. 54For cement manufacturing, incinerators, internal combustion engines and process heaters, the table indicates that the same control technology (at the same cost) would be selected whether the cost ceiling for each source is $3,000, $4,000, or $5,000 per ton; thus the average

cost-effectiveness number for these source categories is the same in each column. For glass manufacturing, the table indicates that additional

emissions reductions would be obtained from more effective and more costly control technologies as the cost ceiling increase.

The following discussion explains the

controls determined by EPA to be highly

cost-effective for each source category.

The EPA has analyzed the

implications of each State limiting

trading within its borders compared to

entering into a common trading program

with all other States, provided that

States choose to control EGUs at an

average level of 0.15 lb/mmBtu. In the

case of intrastate trading, EPA found

that the average cost per ton of the

resulting ozone season NOX reduction

was about $1,499 per ton. This result

from the IPM model was for all the

States together considering changes in

dispatch and other aspects of the future

operation of the nation’s power system.

Individual State results were not

provided by the model. As explained

below, EPA expects that individual

State cost per ton results are likely to be

fairly close to this collective result.

For a regionwide budget based on

0.15 lb/mmBtu, EPA’s analyses suggest

that whether (1) there were individual

State trading programs, or (2) a single

regionwide trading program, all States

experienced a substantial reduction in

summer NOX emissions from Base Case

emissions levels. For this to occur, there

have to be similar opportunities

throughout the SIP call region for highly

cost-effective reductions to occur at

EGUs. If this were not true, EPA would

have found, in the case where there is

a single trading program across the

entire SIP call region, that some States

reduce a much greater share of their

NOX emissions than other States do.

The fact that there are similar

opportunities for NOX reductions in

each of the States indicates that if there

were individual State trading programs

in place they would each generally have

an average cost effectiveness for

reducing ozone season NOX emissions

that is fairly close to the cost

effectiveness of trading programs in

other States. Therefore, each State is

generally likely to have an average cost

effectiveness of about $1,550 per ton,

the amount we found in the results of

the IPM model run for a scenario where

each State ran its own trading program.

a. Electricity Generating Boilers and

Turbines. For EGUs larger than 25 MWe,

the control level was determined by

applying a uniform NOX emissions rate

regionwide. The cost-effectiveness for

each control level was determined using

the IPM. Details regarding the

methodologies used can be found in the

Regulatory Impact Analysis of this

rulemaking. Table 2 summarizes the

control levels and resulting costeffectiveness of three options analyzed.

A regionwide level of 0.20 lb/mmBtu

was rejected because though it resulted

in an average cost effectiveness of less

than $2,000 per ton, the air quality

benefits were less than those for the 0.15

lb/mmBtu level which was also less

than $2,000 per ton. The results suggest

that a regionwide level of 0.15 lb/

mmBtu should be assumed for this

source category when calculating the

amount of emissions that should be

considered significant and therefore

prohibited in each covered State. This

control level has an average costeffectiveness of $1,468 per ozone season

ton removed. This amount is consistent

with the range for cost-effectiveness that

EPA has derived from recently adopted

(or proposed to be adopted) control

measures. As discussed later in this

preamble, EPA has determined that EGU

sources are fully capable of

implementing this level of control by

May 1, 2003.

The EPA estimates that a control level

based on 0.12 lb/mmBtu, has a cost

effectiveness of $1,760 per ozone season

ton removed, which is within the upper

range of cost effectiveness. This estimate

is based on the Agency’s best estimates

of several key assumptions on the

performance of pollution control

technologies and electricity generation

requirements in the future which the

Agency thoroughly researched over the

last two years. Given that the cost per

ton estimate for 0.12 lb/mmBtu trading

is much closer to $2,000 than the 0.15

lb/mmBtu trading, EPA is not as

confident about the robustness of the

results. Also, although EPA is very

comfortable that a 0.15 lb/mmBtu

trading program beginning in 2003 will

not lead to installation of SCR

technology at a level and in a manner

that will be difficult to implement or

result in reliability problems for electric

power generation, the Agency’s level of

comfort is not as high in considering

0.12 lb/mmBtu-based trading.55 With a

strong need to implement a program by

2003 that is recognized by the States as

practical, necessary, and broadly

accepted as highly cost effective, the

Agency has decided to base the
57402 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

emissions budgets for EGUs on a 0.15

lb/mmBtu trading level of control.

It should be noted that the costeffectiveness values for EGUs were

calculated using a slightly older version

of the final EGU inventory. Changes

made to the inventory and growth

assumptions resulted in decreasing the

final regionwide allowable emission

level for EGUs, under the 0.15 option,

to 543,825 tons per year from 563,785

tons per year. Reducing the allowable

regionwide emissions increased the

average cost-effectiveness value of the

0.15 option from $1,468/ton, to $1,503/

ton.

b. Other Stationary Sources. The

appropriate cost-effective control level

for large non-EGU source categories was

determined by evaluating various

regulatory alternatives. For industrial

boilers and turbines (i.e., boilers and

turbines greater than 250 mm/Btu per

hour or with NOX emissions greater

than 1 tpd), the control level was

determined by applying a uniform

percent reduction regionwide in

increments of 10 percent. For all other

stationary sources, the control level was

determined by applying sourcecategory-specific cost-effectiveness

thresholds, because trading was not

assumed to be readily available for these

source categories. Details regarding the

methodologies used are in the

Regulatory Impact Analysis. Table 2

summarizes the control levels and

resulting cost-effectiveness for each

option under each category.

Further, for large non-EGUs, the costeffectiveness determination includes

estimates of the additional emissions

monitoring costs that sources would

incur in order to participate in a trading

program. Some non-EGUs already

monitor their emissions. In the NPR,

EPA had not included monitoring costs

in the cost-effectiveness determination

because such costs had not been

estimated at that time. Since then, EPA

has evaluated monitoring system costs.

These costs are defined in terms of

dollars per ton of NOX removed so that

they can be combined with the costeffectiveness figures related to control

costs. Since monitoring costs do not

vary with the level of control, the cost

per ton for monitoring varies in

accordance with the amount of control

being required. For purposes of this

analysis, the level of control was

assumed to be the level of control used

to calculate the budget. Monitoring costs

varied from about $150 to $400 per ton

of NOX removed, depending on the type

of source category.

The EPA, therefore, determines that:

(1) For large non-electricity-generating

industrial boilers and turbines, a control

level corresponding to 60 percent

reduction from baseline levels is highly

cost-effective (this percent reduction

corresponds to a regionwide control

level of about 0.17 lb/mmBtu); and (2)

for large internal combustion engines

and cement manufacturing sources, a

control level corresponding to the

application of NOX reduction

technology costing no more than

$5,000/ton for each source is, on

average, highly cost effective. As

indicated in Table 2 and described in

detail in the RIA, these control levels

are associated with a cost effectiveness

of approximately $1,467/ton for boilers

and turbines, $1,458/ton for cement

manufacturing, and $1,215/ton for

internal combustion engines. This

results in an average emissions

reduction from uncontrolled emissions

of 90 percent for internal combustion

engines and 30 percent for cement

manufacturing sources. The EPA notes

that States may include these source

categories in the model NOX budget

trading program, further assuring that

each source would be able to costeffectively meet its reduction

requirements. The EPA determined that

controlling glass manufacturing sources,

incinerators, and process heaters was

not highly cost-effective because all the

options analyzed for these source

categories cost more than $2,000 per ton

of NOX removed. Thus, no additional

controls are assumed for these sources

when determining the significant

amounts that must be reduced in each

State.

2. Sources Not Included In the Costeffectiveness Determination

For the following groups of sources,

EPA is determining that no additional

control measures or levels of control

should be assumed in this rulemaking,

for the reasons described.

a. Area Sources. In the NPR, EPA

noted that control levels for area sources

(i.e., sources other than mobile or point

sources) could not be determined based

on available information concerning

applicable control technologies.

Comments to the NPR did not identify

specific NOX control technologies that

were both technologically feasible and

highly cost-effective. Because EPA has

no new information on applicable

control technologies for area sources, no

additional control level is assumed for

these sources in this rulemaking.

Further discussion concerning area

sources can be found in Section III,

below, of this preamble.

b. Small Point Sources. For the

purposes of this rulemaking, EPA

considers the following sizes of point

sources to be small: (1) Electricity

generating boilers and turbines serving

a generator 25 MWe or less, and (2)

other point sources with a heat input of

250 mmBtu/hr or less and which emit

less than one ton of NOX per average

summer day. In the NPR, EPA stated

that the collective emissions from small

sources were relatively small (in the

context of this rulemaking) and the

administrative burden, to the States and

regulated entities, of controlling such

sources was likely to be considerable.

As a result, in the NPR, EPA proposed

not to assume reductions from these

sources in establishing the State

budgets.

Comments to the NPR did not identify

specific approaches that would result in

significant emission reductions and be

administratively efficient in controlling

these sources. On the contrary, many

comments encouraged EPA to exclude

small point sources from any budget

calculations for this rulemaking.

Therefore, in today’s action, EPA is

not assuming additional control levels

for these sources. Further discussion

concerning small point sources may be

found in section III, below, of this

preamble.

c. Mobile Sources. In the NPR, EPA

noted that it could not identify any

additional NOX controls that States

could implement for mobile or nonroad

sources beyond those already reflected

in the proposed State NOX budgets that

were both technologically feasible and

cost-effective, relative to point sources

covered by this rule, for the purposes of

reducing NOX. Several commenters

stated that the EPA should require

States to implement additional

reductions for mobile sources. However,

these commenters did not identify

specific, new, technologically feasible

mobile source NOX controls that were

highly cost-effective by the standards of

today’s action. The EPA has reexamined the availability of mobile

source control measures available to

States, as discussed in more detail in

sections III.D. and III.E. below, and has

not identified any such controls that are

both technologically feasible and highly

cost-effective for NOX control.

Therefore, the States’ final NOX budgets

promulgated in today’s action do not

assume implementation of additional

highway or nonroad mobile source

controls or expansion of existing

controls beyond those described in the

NPR. Further discussion concerning

mobile sources, including the national

measures EPA has assumed for purposes

of today’s rule, can be found in Section

III, Determination of Budgets.

d. Other stationary sources. The EPA

does not assume, in this rulemaking,

any additional control measures or
Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations 57403

56As described elsewhere, the controls

specifically required under the CAA include the

controls identified in the modeling baseline, as well

as certain Federal controls such as NLEV. These

controls do not include any additional reductions

that may be required in the local nonattainment

areas as part of their attainment demonstrations.

lower emissions levels for municipal

waste combustors because these

combustors are already being controlled

through MACT regulations. Moreover,

no additional control measures were

assumed for source categories with

relatively small NOX emissions (e.g.,

iron and steel mills, nitric acid

manufacturing sources, space heaters,

lime kilns, recovery plants, and engine

test facilities). Further discussion

concerning why controls were not

assumed for these source categories may

be found in Section III of this preamble.

e. Conclusion. The above discussion

described the controls for various source

categories that EPA considers to be

highly cost-effective. The next step in

the process is to determine the amounts

of NOX emissions that would be

eliminated by applying these highly

cost-effective controls to the respective

source categories. The EPA considers

those emissions to be the amounts that

contribute significantly to

nonattainment in, or interfere with

maintenance by, downwind States. By

assuming that reductions of this

magnitude should occur, EPA

determined the resulting State-specific

‘‘budget.’’ Section III, Determination of

Budgets describes the process EPA used

to determine each State’s budget and

discusses comments received on the

NPR.

E. Other Considerations

As described above, EPA determined

the amount of emissions that

significantly contribute to downwind

nonattainment from sources in a

particular upwind State primarily by (i)

evaluating, with respect to each upwind

State, several air quality related factors,

including determining that all emissions

from the State have a sufficiently great

impact downwind (in the context of the

collective contribution nature of the

ozone problem); and (ii) determining the

amount of that State’s emissions that

can be eliminated through the

application of cost-effective controls.

Before reaching a conclusion, EPA

evaluated several secondary, and more

general, considerations. These include:

• The consistency of the regional

reductions with the attainment needs of

the downwind areas with

nonattainment problems

• The overall fairness of the control

regimes required of the downwind and

upwind areas, including the extent of

the controls required or implemented by

the downwind and upwind areas

• General cost considerations,

including the relative cost-effectiveness

of additional downwind controls

compared to upwind controls This

section discusses these additional

considerations.

1. Consistency of Regional Reductions

With Attainment Needs of Downwind

Areas

a. General Discussion. Currently, air

quality levels in the eastern part of the

United States are above the 1-hour

NAAQS in various, primarily urban,

areas. Air quality levels are also above

the 8-hour NAAQS in those same areas,

as well as many others.

The OTAG, and subsequently EPA,

have conducted region-wide air quality

modeling, using the UAM-V model,

which shows that in approximately 20

primarily urban areas, the 1-hour

nonattainment problem will persist by

the year 2007, even after all of the

controls specifically required under the

CAA as well as Federal measures are

implemented.56 This nonattainment

problem that remains after

implementation of those mandated

controls may be termed ‘‘residual

nonattainment.’’ For the 8-hour NAAQS

modeling shows that under the same

circumstances, at least one urban area

that is linked to each upwind State will

continue to experience residual

nonattainment, and significantly more

areas will be in nonattainment as well.

Further, as discussed above, OTAG’s

subregional modeling as well as EPA’s

CAMx modeling and State-by-State

zero-out UAM–V modeling, indicate

that upwind States contribute

significantly to those downwind

nonattainment problems under both

standards. In general, under the 1-hour

standard, emissions from each upwind

State affect at least several, primarily

urban, nonattainment areas downwind.

For example, each of the midwest/

southern States of Ohio, Kentucky,

Tennessee, West Virginia, Virginia, and

North Carolina affects between five and

eight downwind nonattainment areas.

Under the 8-hour standard, emissions

from each upwind State affect

nonattainment problems that comprise

an even larger geographic area. For

example, Ohio, Kentucky, Tennessee,

West Virginia, Virginia, and North

Carolina each affect between eight to

thirteen downwind States with

nonattainment problems.

As described in section IV below, EPA

has conducted additional regionwide

modeling which shows that upwind

reductions comparable to those required

under today’s rule have an appreciable

impact on downwind nonattainment

problems under both NAAQS. The

downwind impact from each individual

upwind State’s reductions may be

relatively small, but the impact from all

upwind reductions, collectively, is

appreciable. This regionwide

modeling— which employs the UAM–V

model relied upon by OTAG and also

used by EPA for today’s action—

indicates that even after implementation

of the regional reductions, which help

downwind areas make progress toward

attainment, certain downwind areas

under the 1-hour NAAQS, and

numerous downwind areas under the 8-

hour NAAQS, will experience residual

nonattainment. In addition, under the 8-

hour NAAQS, many other areas with

nonattainment problems are expected to

reach attainment based solely on the

regional reductions.

Furthermore, as mentioned earlier,

the above-described modeling indicates

no upwind States whose required

regional reductions, in combination

with the other regional reductions and

CAA required controls, provide more

ozone reduction than is necessary for

every downwind nonattainment

problem affected by that upwind State

to attain under each NAAQS. That is,

there is no instance of ‘‘overkill,’’ so that

none of the upwind reductions required

under today’s action is more than

necessary to ameliorate downwind

nonattainment.

b. 8-Hour Nonattainment Problems.

As indicated above, the upwind

reductions are useful in ameliorating

downwind nonattainment under both

NAAQS, but they are particularly useful

in areas with nonattainment problems

under the 8-hour NAAQS because more

areas have such problems under that

standard. Emissions reductions from

each upwind State affect a broader

swath of downwind 8-hour

nonattainment problems, including

problems adjacent to, and further away

from, the upwind State. For example,

emissions from Ohio affect

nonattainment problems in each State

adjacent to Ohio, as well as numerous

States further away. As noted above, in

some cases, the upwind reductions

eliminate the downwind nonattainment

problem; in other cases, those

reductions ameliorate the downwind

problem but residual nonattainment

remains.

Moreover, under the 8-hour NAAQS,

upwind contributions tend to be a

particularly large percentage of the

downwind nonattainment problem. For

example, along the Northeast corridor,

cumulatively upwind States including

adjacent States, contribute 83 percent of
57404 Federal Register / Vol. 63, No. 207 /Tuesday, October 27, 1998 /Rules and Regulations

57As noted in Section II.A., EPA proposed two

analytical approaches, the second of which is the

same as EPA is today promulgating. The

commenters’s criticisms seem to apply equally to

both approaches.

Washington, DC’s nonattainment

problem; 68 percent of Maryland’s

nonattainment problem; 65 percent of

Pennsylvania’s nonattainment problem;

and 85–88 percent of each of New

Jersey’s, New York’s, Connecticut’s, and

Massachusett’s nonattainment

problems. These high levels of upwind

contributions to widespread

nonattainment problems—both near to,

and far from, the upwind State—

indicate that the regional reductions

from the upwind areas may be expected

to be useful in ameliorating downwind

nonattainment under the 8-hour

NAAQS.

c. Commenters’ Concerns.

Commenters argued that in the NPR that

EPA failed to demonstrate that the

proposed reductions in upwind

emissions were necessary for downwind

areas to demonstrate attainment.

Commenters pointed out the lack of

local attainment demonstrations under

the 1-hour NAAQS.57

The EPA does not believe a local

attainment demonstration is required

before EPA can call on upwind States to

reduce emissions pursuant to section

110(a)(2)(D). The EPA believes that

available modeling analyses

demonstrate that upwind reductions are

necessary to help downwind areas come

into attainment. The OTAG and EPA

subregional modeling, UAM–V State-byState zero-out modeling, and the CAMx

modeling, described above, link each

upwind State’s emissions and

downwind attainment needs, in a

manner that is sufficient to support

today’s action. To reiterate, under the 1-

hour NAAQS, the emissions reductions

from each upwind State, combined with

other emissions reductions, are needed

to reduce downwind nonattainment

problems. That need is underlined by

the fact that the modeling relied on for

today’s action indicates residual

nonattainment after implementation of

all required controls and Federal

measures. Even after implementation of

the regional reductions, there is residual

nonattainment for at least one

downwind area linked to each upwind

State. The same is true for the 8-hour

NAAQS, as noted above.

The EPA recognizes that in the future,

additional information may become

available that would shed further light

on the amount of emissions reductions

needed for downwind areas to attain the

NAAQS. Local-scale modeling may

indicate more precisely the ambient

impact of regional and local reductions

on downwind nonattainment areas and

the amount of any residual

nonattainment. Nevertheless, it should

be emphasized that the models relied on

for today’s action are state-of-the-art,

and that their various inputs—

particularly the inventories—have

recently undergone close scrutiny and

careful refinement through public

comment and expert analysis.

Accordingly, EPA believes that the

overall model results indicating the

general impact of upwind emissions and

reductions in emissions should be

viewed as valid. Accordingly, EPA

believes that it has an adequate base of

information to require the regional

reductions under the 1-hour and 8-hour

NAAQS at this time.

2. Equity Considerations

The EPA believes further justification

for today’s action is provided by overall

considerations of fairness related to the

control regimes required of the

downwind and upwind areas, including

the extent of the controls required or

implemented by those areas.

The OTAG and EPA modeling

analyses clearly indicate that upwind

emissions contribute more than trivial

amounts to downwind nonattainment

problems. As a result, upwind emitters

are exacerbating the health and welfare

risks faced by those who live and work

in downwind areas afflicted with

unhealthful levels of ozone. The EPA

believes that the principle of simple

fairness applies here: upwind States

should reduce their emissions that visit

those health and welfare problems upon

their downwind neighbors. Otherwise,

their downwind neighbors would be

obliged to pay additional costs to reduce

local emissions beyond what would

otherwise be necessary to protect their

health from upwind emissions. In EPA’s

judgment, it is fair to require the

upwind sources to reduce at least the

portion of their emissions for which

highly cost-effective controls are

available. Indeed, fairness

considerations would point towards

requiring upwind reductions even if

there were some degree of cost

inefficiency.

Further, it should be recognized that

the major urban nonattainment areas

have been required to incur control

costs for ozone precursors since shortly

after the 1970 CAA Amendments. In

general, over the past quarter of a

century, these areas have implemented

SIP controls that, in combination with

Federal measures, place ozone-related

controls on virtually all portions of their

inventory of ozone precursors,

including VOCs as well as NOx. The Air

Quality Modeling TSD includes

descriptions of the control measures in

place for several major urban

nonattainment areas. Although not

every major urban nonattainment area

has complied with every CAA

requirement for ozone precursors, the

major urban nonattainment areas have

complied with almost all of these

requirements, and the CAA provides

remedies to assure complete

implementation of the required

provisions. These measures have

already lead to substantial reductions in

ozone levels. By comparison, upwind

States have not implemented reductions

intended to reduce their impact on

downwind nonattainment areas.

3. General Cost Considerations

The EPA also generally considered

the cost-effectiveness of additional local

reductions in the 1-hour ozone

nonattainment areas. The EPA

conducted this analysis as part of its

Regulatory Impact Analysis, completed

under Executive Order 12866, for the

rulemaking in which EPA revised the

ozone NAAQS, 62 FR 38866 (July 18,

1997). The EPA surveyed the additional

VOC and NOx controls available in areas

throughout the country that are

expected to be nonattainment under

either NAAQS. The EPA ascertained

that nationally, on average, these

additional measures would cost

approximately $4,300 per ton removed

during the ozone season. See ‘‘Control

Measures Analysis of Ozone and PM

Alternatives: Methodology and Results,’’

July 17, 1997, table VII–2, p. 56.

Although this figure is a national

average, it provides a basis to conclude

that local reductions may be expected to

be more expensive than the

approximately $1,500 in cost per ozoneseason ton removed for the regional NOx

reductions required in today’s

rulemaking.

Commenters criticized EPA’s proposal

to measure cost-effectiveness in terms of

cost per ton of emissions removed

because it did not take into account the

ambient impact downwind of the

emissions reductions. Commenters

cautioned that under certain

circumstances, a high level of emissions

reductions upwind may result in high

costs (even though cost-effective on a

per-ton basis), but relatively little

ambient benefit downwind.

Commenters emphasized that emissions

reductions tend to have the greatest

ambient benefit when they are within,

or adjacent to, the area with the

nonattainment problem. Commenters

also said that emissions reductions

further upwind have less ambient

benefit. Accordingly, commenters stated

that EPA’s cost-effectiveness