Transportation Conformity Rule Amendments for the New 8-Hour Ozone and PM2.5 National Ambient Air Quality Standards and Miscellaneous Revisions for Existing Areas

Federal RegisterNov 5, 2003

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 93

[FRL-7579-8]

RIN 2060-AL73

Transportation Conformity Rule Amendments for the New 8-Hour Ozone and PM

2.5

National Ambient Air Quality Standards and Miscellaneous Revisions for Existing Areas

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

Today we (EPA) are proposing to amend the transportation conformity rule to include criteria and procedures for the new 8-hour ozone and fine particulate matter (PM

2.5

) national ambient air quality standards (NAAQS or “standards”). Transportation conformity is required under Clean Air Act section 176(c) to ensure that federally supported highway and transit project activities are consistent with (“conform to”) the purpose of a State air quality implementation plan (SIP). We are conducting this rulemaking to revise the conformity regulation in the context of EPA's broader strategies for implementing the new ozone and PM

2.5

standards.

The proposal provides guidance for when conformity will first apply in areas that are designated nonattainment for the 8-hour ozone and PM

2.5

standards. This portion of the proposal discusses the implementation of the statutory one-year conformity grace period and proposed revocation of the 1-hour ozone standard, although EPA is not seeking comment through today's proposal on the revocation options themselves. Today's proposal also describes when transportation conformity applies in areas that have approved 8-hour ozone Early Action Compacts (EACs).

The proposal also describes the general requirements for conducting conformity determinations for the new standards, such as the conformity test(s) that would apply before and after adequate or approved SIP motor vehicle emissions budgets are established. In addition, this rulemaking proposes to amend the conformity regulations to specifically include PM

2.5

as a criteria pollutant subject to transportation conformity and outlines the specific conformity requirements that would apply in newly designated PM

2.5

nonattainment areas. In particular, the proposal includes options for when conformity would apply for various PM

2.5

precursors and fugitive dust, as well as options for PM

2.5

hot-spot requirements for project-level conformity determinations. EPA seeks comments and suggestions for future guidance on adjusting fugitive dust emissions for PM

2.5

conformity analyses.

In addition to issues related to the new ozone and PM

2.5

standards, EPA is proposing a few miscellaneous rule revisions to clarify the existing regulation and improve implementation.

The Department of Transportation (DOT) is EPA's Federal partner in implementing the transportation conformity regulation. We have consulted with DOT on the development of this rulemaking and DOT concurs with this proposal. EPA has also met with transportation and environmental organizations to discuss this rulemaking and the proposal reflects the comments that we received through these stakeholder discussions.

DATES:

Written comments on this proposal must be received on or before December 22, 2003. EPA will conduct one public hearing on this proposal beginning at 9:30 a.m. on Thursday, December 4, 2003, in Washington, DC. As described in Section XVI. of this proposal, the hearing will continue throughout the day until all testimony has been presented or 5 p.m., whichever is earlier.

ADDRESSES:

Comments may be submitted by mail to: Air Docket, Environmental Protection Agency, Mailcode: 6102T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention Docket ID No. OAR-2003-0049. Comments may also be submitted electronically, by facsimile, or through hand delivery/courier. Follow the detailed instructions for submission as provided in section I.C. of the

SUPPLEMENTARY INFORMATION

section.

The public hearing will be held in Washington, DC, at the Washington Marriott Hotel at 1221 22nd St., NW., Washington, DC 20037, (202) 872-1500.

FOR FURTHER INFORMATION CONTACT:

Meg Patulski, State Measures and Conformity Group, Transportation and Regional Programs Division, U.S. Environmental Protection Agency, 2000 Traverwood Road, Ann Arbor, MI 48105,

patulski.meg@epa.gov,

(734) 214-4842; or, Rudy Kapichak, State Measures and Conformity Group, Transportation and Regional Programs Division, U.S. Environmental Protection Agency, 2000 Traverwood Road, Ann Arbor, MI 48105,

kapichak.rudolph@epa.gov,

(734) 214-4574.

SUPPLEMENTARY INFORMATION:

The contents of this preamble are listed in the following outline:

I. General Information

A. Regulated Entities

B. How Can I Get Copies of This Document?

C. How and to Whom Do I Submit Comments?

D. How Should I Submit CBI to the Agency?

E. What Should I Consider as I Prepare My Comments for EPA?

II. Background on the Transportation Conformity Rule

A. What Is Transportation Conformity?

B. Why Is EPA Conducting This Rulemaking?

C. Does This Proposal Include the Entire Transportation Conformity Regulation?

III. Conformity Grace Period and Revocation of the 1-Hour Ozone Standard

A. When Will Conformity Apply for the 8-Hour Ozone and PM

2.5

Standards?

B. When Does Conformity Stop Applying for the 1-Hour Ozone Standard?

C. When and for What Ozone Standard Does Conformity Apply in Areas With an Early Action Compact for the 8-Hour Ozone Standard?

IV. General Changes in Interim Emissions Tests

A. Background

B. Baseline Year Test for 8-Hour Ozone and PM

2.5

Areas

C. Build/No-Build Test for Existing and New Nonattainment Areas

D. Test Options for Ozone and CO Nonattainment Areas of Higher Classifications

V. Regional Conformity Tests in 8-Hour Ozone Areas That Do Not Have 1-Hour Ozone SIPs

A. What Are We Proposing?

B. Why Are We Proposing These Options?

VI. Regional Conformity Tests in 8-Hour Ozone Areas That Have 1-Hour Ozone SIPs

A. What Are We Proposing?

B. Why Are We Proposing These Options?

VII. Regional Conformity Tests in PM

2.5

Areas

A. What Are We Proposing?

B. Why Are We Proposing These Options?

VIII. Consideration of Direct PM

2.5

and PM

2.5

Precursors in Regional Emissions Analyses

A. What Are We Proposing?

B. Why Are We Proposing These Options?

IX. Re-Entrained Road Dust in PM

2.5

Regional Emissions Analyses

A. Background

B. What Are We Proposing?

C. Why Are We Proposing These Options?

D. Request for Comment on Estimating Road Dust Emissions

X. Construction-Related Fugitive Dust in PM

2.5

Regional Emissions Analyses

A. Background

B. What Are We Proposing?

C. Why Are We Proposing This Option?

D. Implementation and Request for Additional Information

XI. Compliance With PM

2.5

SIP Control Measures

A. What Are We Proposing?

B. Why Are We Proposing This Option?

XII. PM

2.5

Hot-Spot Analyses

A. What Are We Proposing?

B. Existing Research on PM

2.5

Hot-Spots and Request for Additional Information

C. Why Are We Proposing These Options?

XIII. PM

Hot-spot Analyses

D. What Are We Proposing?

E. Why Are We Considering These Options?

XIV. Miscellaneous Revisions for New and Existing Areas

A. Definitions

B. Areas with Insignificant Motor Vehicle Emissions

C. Limited Maintenance Plans

D. Grace Period for Transportation Modeling and Plan Content Requirements in Certain Ozone and CO Areas

E. Minor Clarification to the List of PM

Precursors

F. Clarification of Requirements for Non-federal Projects in Isolated Rural Areas

G. Use of Adequate and Approved Budgets in Conformity

XV. How Does Today's Proposal Affect Conformity SIPs?

XVI. Public Hearing

XVII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments

G. Executive Order 13045: Protection of Children from Environmental Health and Safety Risks

H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution or Use

I. National Technology Transfer and Advancement Act

I. General Information

A. Regulated Entities

Entities potentially regulated by the conformity rule are those that adopt, approve, or fund transportation plans, programs, or projects under title 23 U.S.C. or title 49 U.S.C. Regulated categories and entities affected by today's action include:

Category

Examples of regulated entities

Local government

Local transportation and air quality agencies, including metropolitan planning organizations (MPOs).

State government

State transportation and air quality agencies.

Federal government

Department of Transportation (Federal Highway Administration (FHWA) and Federal Transit Administration (FTA)).

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this proposed rule. This table lists the types of entities of which EPA is aware that potentially could be regulated by the conformity rule. Other types of entities not listed in the table could also be regulated. To determine whether your organization is regulated by this action, you should carefully examine the applicability requirements in § 93.102 of the transportation conformity rule. If you have questions regarding the applicability of this action to a particular entity, consult the persons listed in the preceding

FOR FURTHER INFORMATION CONTACT

section.

B. How Can I Get Copies of This Document?

1. Docket.

EPA has established an official public docket for this action under Docket ID No. OAR-2003-0049. The official public docket consists of the documents specifically referenced in this action, any public comments received, and other information related to this action. Although a part of the official docket, the public docket does not include Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. The official public docket is the collection of materials that is available for public viewing at the Air Docket in the EPA Docket Center, (EPA/DC) EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. The EPA Docket Center Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742.

2. Electronic Access.

You may access this

Federal Register

document electronically through EPA's Transportation Conformity Web site at

http://www.epa.gov/otaq/transp/traqconf.htm

. You may also access this document electronically under the

Federal Register

listings at

http://www.epa.gov/fedrgstr/

An electronic version of the public docket is available through EPA's electronic public docket and comment system, EPA Dockets. You may use EPA Dockets at

http://www.epa.gov/edocket/

to submit or view public comments, access the index listing of the contents of the official public docket, and to access those documents in the public docket that are available electronically. Once in the system, select “search,” then key in the appropriate docket identification number.

Certain types of information will not be placed in the EPA Dockets. Information claimed as CBI and other information for which disclosure is restricted by statute is not included in the official public docket and will not be available for public viewing in EPA's electronic public docket. EPA's policy is that copyrighted material will not be placed in EPA's electronic public docket but will be available only in printed, paper form in the official public docket. To the extent feasible, publicly available docket materials will be made available in EPA's electronic public docket. When a document is selected from the index list in EPA Dockets, the system will identify whether the document is available for viewing in EPA's electronic public docket. Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the docket facility identified in section I.B.1. above. EPA intends to work towards providing electronic access in the future to all of the publicly available docket materials through EPA's electronic public docket.

For public commenters, it is important to note that EPA's policy is that public comments, whether submitted electronically or in paper, will be made available for public viewing in EPA's electronic public docket as EPA receives them and without change, unless the comment contains copyrighted material, CBI, or other information for which disclosure is restricted by statute. When EPA identifies a comment containing copyrighted material, EPA will provide a reference to that material in the version of the comment that is placed in EPA's electronic public docket. The entire printed comment, including the

copyrighted material, will be available in the public docket.

Public comments submitted on computer disks that are mailed or delivered to the docket will be transferred to EPA's electronic public docket. Public comments that are mailed or delivered to the docket will be scanned and placed in EPA's electronic public docket. Where practical, physical objects will be photographed, and the photograph will be placed in EPA's electronic public docket along with a brief description written by the docket staff.

For additional information about EPA's electronic public docket visit EPA Dockets online or

see

67 FR 38102, May 31, 2002.

C. How and to Whom Do I Submit Comments?

You may submit comments electronically, by mail, by facsimile, or through hand delivery/courier. To ensure proper receipt by EPA, identify the appropriate docket identification number in the subject line on the first page of your comment. Please ensure that your comments are submitted within the specified comment period. Comments received after the close of the comment period will be marked “late.” Although EPA is not required to consider these late comments, we may do so as appropriate, considering time and volume constraints.

1. Electronically.

If you submit an electronic comment as prescribed below, EPA recommends that you include your name, mailing address, and an e-mail address or other contact information in the body of your comment. You should also include this contact information on the outside of any disk or CD ROM you submit, and in any cover letter accompanying the disk or CD ROM. This ensures that you can be identified as the submitter of the comment and allows EPA to contact you in case EPA cannot read your comment due to technical difficulties or needs further information on the substance of your comment. EPA's policy is that EPA will not edit your comment, and any identifying or contact information provided in the body of a comment will be included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket. However, if EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to further consider your comment.

i. EPA Dockets.

Your use of EPA's electronic public docket to submit comments to EPA electronically is EPA's preferred method for receiving comments. Go directly to EPA Dockets at

http://www.epa.gov/edocket

, and follow the online instructions for submitting comments. To access EPA's electronic public docket from the EPA Internet Home Page, select “Information Sources,” “Dockets,” and “EPA Dockets.” Once in the system, select “search,” and then key in Docket ID No. OAR-2003-0049. The system is an “anonymous access” system, which means EPA will not know your identity, e-mail address, or other contact information unless you provide it in the body of your comment.

ii. E-mail.

Comments may be sent by electronic mail (e-mail) to

a-and-r-docket@epa.gov

, Attention Air Docket ID No. OAR-2003-0049. In contrast to EPA's electronic public docket, EPA's e-mail system is not an “anonymous access” system. If you send an e-mail comment directly to the docket without going through EPA's electronic public docket, EPA's e-mail system automatically captures your e-mail address. E-mail addresses that are automatically captured by EPA's e-mail system are included as part of the comment that is placed in the official public docket, and are thus made available in EPA's electronic public docket.

iii. Disk or CD ROM.

You may submit comments on a disk or CD ROM that you mail to the mailing address identified in section I.C.2. These electronic submissions will be accepted only in either WordPerfect or ASCII file format. Please avoid the use of special characters and any form of encryption, as this may adversely affect our ability to read these submissions.

2. By Mail

. Send two copies of your comments to: Air Docket, Environmental Protection Agency, Mailcode: 6102T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention Docket ID No. OAR-2003-0049.

3. By Hand Delivery or Courier

. Deliver two copies of your comments to: EPA Docket Center, Room B102, EPA West Building, 1301 Constitution Avenue, NW., Washington, DC, Attention Air Docket ID No. OAR-2003-0049. Such deliveries can only be accepted during the Docket's normal hours of operation as identified in Section I.B.1.

4. By Facsimile

. Fax your comments to: (202) 566-1741, Attention Docket ID No. OAR-2003-0049.

D. How Should I Submit CBI to the Agency?

Do not submit information that you consider to be CBI electronically through EPA's electronic public docket or by e-mail. Send or deliver information identified as “CBI only” to the following address: Attention: Meg Patulski, State Measures and Conformity Group, Transportation and Regional Programs Division, U.S. Environmental Protection Agency, 2000 Traverwood Road, Ann Arbor, MI 48105, Docket ID No. OAR-2003-0049. You may claim information that you submit to EPA as CBI by marking any part or all of that information as CBI (if you submit CBI on disk or CD ROM, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is CBI). Information so marked will not be publicly disclosed except in accordance with procedures set forth in 40 CFR part 2.

In addition to one complete version of the comment that includes any information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket and EPA's electronic public docket. If you submit the copy that does not contain CBI on disk or CD ROM, mark the outside of the disk or CD ROM clearly indicating that it does not contain CBI. Information not marked as CBI will be included in the public docket and EPA's electronic public docket without prior notice. If you have any questions about CBI or the procedures for claiming CBI, please consult the person identified in the

FOR FURTHER INFORMATION CONTACT

section.

E. What Should I Consider as I Prepare My Comments for EPA?

You may find the following suggestions helpful for preparing your comments:

1. Explain your views as clearly as possible.

2. Describe any assumptions that you used.

3. Provide any technical information and/or data you used that support your views.

4. If you estimate potential burden or costs, explain how you arrived at your estimate.

5. Provide specific examples to illustrate your concerns.

6. Offer alternatives.

7. Make sure to submit your comments by the comment period deadline identified.

8. To ensure proper receipt by EPA, identify the appropriate docket identification number in the subject line on the first page of your response. It would also be helpful if you provided the name, date, and

Federal Register

citation related to your comments.

II. Background on the Transportation Conformity Rule

A. What Is Transportation Conformity?

Transportation conformity is required under Clean Air Act section 176(c) (42 U.S.C. 7506(c)) to ensure that federally supported highway and transit project activities are consistent with (“conform to”) the purpose of the state air quality implementation plan (SIP). Conformity currently applies under EPA's rules to areas that are designated nonattainment, and those redesignated to attainment after 1990 (“maintenance areas” with plans developed under Clean Air Act section 175A) for the criteria pollutants: ozone, coarse particulate matter (PM

), carbon monoxide (CO), and nitrogen dioxide (NO

). Today's proposal would also apply the conformity rule provisions in fine particulate matter (PM

2.5

) areas. Conformity to the purpose of the SIP means that transportation activities will not cause new air quality violations, worsen existing violations, or delay timely attainment of the relevant national ambient air quality standards (NAAQS or “standards”). EPA's transportation conformity rule establishes the criteria and procedures for determining whether transportation activities conform to the SIP.

EPA first promulgated the transportation conformity rule on November 24, 1993 (58 FR 62188), and subsequently published a comprehensive set of amendments on August 15, 1997 (62 FR 43780) that clarified and streamlined language from the 1993 rule. EPA has made other smaller amendments to the rule both before and after the 1997 amendments.

On June 30, 2003, EPA published a proposal that would amend the current conformity rule to be consistent with a March 2, 1999, U.S. Court of Appeals decision (68 FR 38974). The “court proposal” also included several proposed amendments to regulatory provisions that did not directly result from the court decision. EPA has not yet taken a final action on this proposed rulemaking. We are reviewing the public comments on the court proposal and will promulgate a final rule in the future.

Today's proposal should be considered a separate action from the June 30, 2003 court proposal. However, some sections and paragraphs of the conformity rule are addressed in both proposals. For those sections, EPA has repeated the court proposal's regulatory language in today's proposal along with the proposed revisions that address the conformity requirements in 8-hour ozone and PM

2.5

areas.

Other changes to the conformity program could occur through the reauthorization of the Surface Transportation Act, currently entitled the Transportation Equity Act for the 21st Century (TEA-21). However, EPA believes it is prudent to expeditiously pursue the regulatory changes proposed today to ensure that entities subject to conformity for the new air quality standards understand applicable requirements as close to area designations as possible. EPA will continue to monitor the proposed reauthorization proposals for their potential impact on the conformity regulation. If statutory amendments to the conformity program result from TEA-21 reauthorization, EPA would take appropriate action to address such changes.

EPA has consulted with the Department of Transportation (DOT), our federal partners in implementing the transportation conformity regulation, in developing this rulemaking, and DOT concurs with this proposal. EPA has also met with state and local transportation and environmental organizations to discuss this rulemaking. The proposal reflects our consideration of the comments that we received through these stakeholder discussions. Documentation of these stakeholder meetings and specific comments are included in the docket for this rulemaking.

B. Why Is EPA Conducting This Rulemaking?

EPA has developed new 8-hour ozone and PM

2.5

air quality standards, and anticipates designating areas as nonattainment for these new standards in April and December 2004, respectively. EPA is conducting this rulemaking to provide clear guidance and rules for implementing conformity for these standards. Some of the proposed revisions to the current regulation would provide more options and flexibility in demonstrating conformity. Other proposed changes would also apply to existing 1-hour ozone, CO, PM

and NO

nonattainment and maintenance areas.

The following table provides a roadmap for determining whether a specific proposal included in this rulemaking would apply in your area.

Type of area

Issue being addressed in this proposal

Preamble

section

Proposed

regulatory

section

8-hour ozone

Conformity grace period

III.A

§ 93.102(d).

Revocation of 1-hour ozone standard

III.B

No proposed regulatory amendments.

Early Action Compacts

III.C

No proposed regulatory amendments.

Baseline year test

IV.B

§ 93.119(b).

Build/no-build test (marginal and below classifications and subpart 1 areas)

IV.C

§ 93.119(b)(2).

§ 93.119(g)(2).

Regional conformity tests (moderate and above classifications)

IV.D

§ 93.119(b)(1).

Regional Conformity tests (areas without 1-hour ozone budgets)

§ 93.109(k).

Regional conformity tests (areas with 1-hour ozone budgets

§ 93.109(e).

Definitions

XIV.A.

§ 93.101.

Insignificance

XIV.B

§ 93.109(d).

§ 93.121(c).

Transportation plan and modeling requirements (moderate and above classifications)

XIV.D

§ 93.106(b).

§ 93.122(c).

Non-federal projects (for isolated rural areas only)

XIV.F

§ 93.121(b)(1).

2.5

Applicability

III.A

§ 93.102(b)(1).

Conformity grace period

III.A

§ 93.102(d)

Baseline year test

IV.B

§ 93.119(e)

Build/no-build test

IV.C

§ 93.119(e)

§ 93.119(g)(2)

Regional conformity tests

VII

§ 93.109(i)

Precursors in regional analyses

VIII

§ 93.102(b)(2)

§ 93.119(f)

Re-entrained road dust in regional analyses

§ 93.102(b)(3)

§ 93.119(f)

Construction-related fugitive dust in regional analyses

§ 93.122(f)

Compliance with SIP control measures

§ 93.117.

Hot-spots

XII

No proposed regulatory amendments.

Definitions

XIV.A

§ 93.101.

Insignificance

XIV.B

§ 93.109(k).

§ 93.121(c).

Non-federal projects (for isolated rural areas only)

XIV.F

§ 93.121(b)(1).

1-hour ozone

Revocation of 1-hour ozone standard

III.B

No proposed regulatory amendments.

Build/no-build test (marginal and below classifications)

IV.C

§ 93.119(b)(2).

§ 93.119(g)(2).

Regional conformity tests (moderate and above classifications)

IV.D

§ 93.119(b)(1).

Definitions

XIV.A

§ 93.101.

Insignificance

XIV.B

§ 93.109(k)

§ 93.121(c).

Limited maintenance plans

XIV.C

§ 93.101.

§ 93.109(j).

§ 93.121(c).

Transportation plan and modeling requirements (moderate and above classifications)

XIV.D

§ 93.106(b).

§ 93.122(c).

Non-federal projects (for isolated rural areas only)

XIV.F

§ 93.121(b)(1).

Clarification to use of approved budgets in conformity

XIV.G

§ 93.109(c).

Build/no-build test

IV.C

§ 93.119(d).

§ 93.119(g)(2).

Compliance with SIP control measures (Request for information only)

No proposed regulatory amendments.

Hot-spots

XIII

No proposed regulatory amendments.

Clarification to Precursors

XIV.E

§ 93.102(b)(2).

§ 93.119(f)(5).

Definitions

XIV.A &

§ 93.101.

Insignificance

XIV.B &

§ 93.109(k).

§ 93.121(c).

Limited maintenance plans

XIV.C

§ 93.101.

§ 93.109(j).

§ 93.121(c).

Non-federal projects (for isolated rural areas only)

XIV.F

§ 93.121(b)(1).

Clarification to use of approved budgets in conformity

XIV.G

§ 93.109(g).

Build/no-build test (lower CO classifications)

IV.C

§ 93.119(c).

§ 93.119(g)(2).

Regional conformity tests (higher CO classifications)

IV.D

§ 93.119(c)(1).

Definitions

XIV.A

§ 93.101.

Insignificance

XIV.B

§ 93.109(k).

§ 93.121(c).

Limited maintenance plans

XIV.C

§ 93.101.

§ 93.109(j).

§ 93.121(c).

Transportation plan and modeling requirements (moderate and serious classifications)

XIV.D

§ 93.106(b).

§ 93.122(c).

Non-federal projects (for isolated rural areas only)

XIV.F

§ 93.121(b)(1).

Clarification to use of approved budgets in conformity

XIV.G

§ 93.109(f).

Build/no-build test

IV.C

§ 93.119(d).

§ 93.119(g)(2).

Definitions

XIV.A

§ 93.101.

Insignificance

XIV.B

§ 93.109(k).

§ 93.121(c).

Non-federal projects (for isolated rural areas only)

XIV.F

§ 93.121(b)(1).

Clarification to use of approved budgets in conformity

XIV.G

§ 93.109(h).

This table illustrates which parts of the proposal are relevant for various pollutants and standards. Please note that Sections V.-VII. provide stand-alone descriptions of the proposed emissions tests for PM

2.5

areas and 8-hour ozone areas with and without existing 1-hour ozone SIPs. For example, if your area expects only to be designated nonattainment under the PM

2.5

standard, you should read section VII. but not sections V. and VI (for 8-hour ozone areas). EPA believes that any redundancy between these sections

is warranted to assist readers who may not need to read the entire proposal.

C. Does This Proposal Include the Entire Transportation Conformity Regulation?

No. The proposed regulatory text is limited to proposed changes to affected portions of the conformity rule. However, a complete version of the conformity rule is available to the public on our transportation conformity website listed in Section I.B.2. of this proposal. The complete version is intended to help reviewers understand today's proposed changes in context with the June 30, 2003 conformity proposal and other existing rule sections that are not proposed to be changed.

III. Conformity Grace Period and Revocation of the 1-Hour Ozone Standard

A. When Will Conformity Apply for the 8-Hour Ozone and PM

2.5

Standards?

Conformity applies one year after the effective date of EPA's initial nonattainment designation for a given pollutant and standard. This one-year conformity grace period is provided by Clean Air Act section 176(c)(6) and § 93.102(d) of the conformity regulation.

Section 93.102(d) currently addresses newly designated nonattainment areas for ozone, CO, PM

and NO

. This proposal would add PM

2.5

to § 93.102(d) of the conformity rule even though the grace period is already available to all newly designated nonattainment areas as a matter of law. Today's proposed change would simply reflect the statutory flexibility in the regulation.

Although the same pollutant, the 8-hour and 1-hour ozone standards are different NAAQS. Therefore, every area that is designated nonattainment for the 8-hour ozone standard will also have a 1-year grace period before conformity applies for that standard, even if the area was designated nonattainment for the 1-hour ozone standard. Areas currently subject to conformity for the 1-hour ozone standard would continue to be subject to such requirements during the 1-year grace period for the 8-hour ozone standard. EPA anticipates designating areas for the 8-hour ozone standard in April 2004. If, for example, designations have a 30-day delayed effective date, conformity for the 8-hour ozone standard would begin to apply in May 2005, since under EPA's regulations the one-year grace period begins upon the effective date of an area's designation. EPA is proposing to include new regulatory definitions for the 1-hour and 8-hour ozone standards in § 93.101. These proposed definitions are consistent with how the standards are described in existing EPA regulations at 40 CFR 50.9 and 40 CFR 50.10, respectively.

Similarly, every area that is designated nonattainment for the PM

2.5

standard will have a one-year grace period before conformity applies for that standard. EPA plans to designate areas for PM

2.5

by December 2004. Under today's proposed § 93.102(b), the conformity rule would apply in areas designated nonattainment for PM

2.5

. Therefore, conformity for the PM

2.5

standard would apply beginning in January 2006, for example, if a 30-day effective date is provided in accordance with § 93.102(d). It is important to note that PM

is a different pollutant than PM

2.5

, and today's proposal does not affect the applicability and general implementation of conformity in PM10 nonattainment and maintenance areas.

EPA anticipates that some areas will be designated as nonattainment for both the 8-hour ozone and PM

2.5

standards. In these areas, conformity for the 8-hour ozone standard will apply one year after the effective date of the area's 8-hour ozone designation, while conformity for PM

2.5

will apply one year after the effective date of the area's PM

2.5

designation.

The following discussion provides more details on the application of the one-year conformity grace period in specific types of newly designated nonattainment areas—metropolitan, donut, and isolated rural areas.

1. Metropolitan Areas

Metropolitan areas are urbanized areas that have a population greater than 50,000 and a designated metropolitan planning organization (MPO) responsible for transportation planning per 23 U.S.C. 134. In general, within one year after the effective date of the initial nonattainment designation for a given pollutant and standard, the area's MPO and DOT must make a conformity determination with regard to that pollutant and standard for the area's transportation plan and TIP. If, at the conclusion of the one-year grace period, the MPO and DOT have not made a plan and TIP conformity determination for the relevant pollutant and standard, the area would be in a conformity “lapse.” As described in section III.B., MPOs must continue to meet conformity requirements for the 1-hour ozone standard for plan, TIP, and project approvals made up until the time that the 1-hour standard is revoked.

During a conformity lapse, only certain projects can receive additional federal funding or approvals to proceed. Such projects include: exempt projects (

e.g.

, safety projects) listed in §§ 93.126, 93.127 and 93.128 of the current conformity rule; transportation control measures in an approved SIP; and, projects or project phases (

e.g.

, right-of-way, final design, construction) that received all required federal funding or approval prior to the conformity lapse. The practical impact of a conformity lapse will vary on an area-by-area basis. For additional information on projects that can proceed during a conformity lapse, see the following guidance memoranda that implement the March 2, 1999 U.S. Court of Appeals decision that affected related provisions of the conformity rule: DOT's January 2, 2002 guidance, published in the

Federal Register

on February 7, 2002 (67 FR 5882); DOT's May 20, 2003, and FTA's April 9, 2003, supplemental guidance documents; as well as EPA's May 14, 1999 guidance memorandum. EPA proposed to incorporate this existing guidance into the conformity regulation on June 30, 2003 (68 FR 38974). A copy of this proposed rulemaking, as well as the guidance listed above, can be downloaded from EPA's transportation conformity Web site listed in section I.B.2. of this proposal.

2. Donut Areas

For the purposes of conformity, a “donut” area is the geographic area outside a metropolitan planning area boundary, but inside a designated nonattainment or maintenance area boundary that includes an MPO. The conformity requirements for donut areas, including the application of the one-year conformity grace period, are generally the same as those for metropolitan areas. Within one year after the effective date of an area's initial nonattainment designation, the existing and planned transportation network for the donut portion of the area (as well as for the metropolitan portion of the area) must demonstrate conformity, or conformity of the metropolitan transportation plan and TIP will lapse as discussed above, and the entire nonattainment area will be unable to obtain additional project funding and approvals at that time.

To demonstrate conformity of its plan and TIP, the adjacent MPO must include in its regional emissions analysis the emissions from the donut area's proposed transportation network and planned project activities. To demonstrate conformity of projects in the donut portion, such projects must have been included in the regional emissions analysis that supports the conformity determination of the metropolitan area's plan and TIP. In nonattainment and maintenance areas with a donut portion, the MPO and

State DOT may choose to include donut area projects in the MPO's plan and TIP. However, this approach is not required by either DOT's planning regulations or the conformity rule.

The interagency consultation group for each newly designated nonattainment area that includes a donut portion should determine how best to consider the donut area transportation system and new donut area projects in the MPO's regional emissions analyses and conformity determinations. For more discussion on how conformity determinations should be made for donut areas, see the preamble to the original conformity rule published on November 24, 1993 (58 FR 62207).

3. Isolated Rural Areas

Isolated rural nonattainment and maintenance areas are areas that do not contain or are not part of any metropolitan planning area as designated under 23 U.S.C. 134 and 49 U.S.C. 5303. Isolated rural areas do not have metropolitan transportation plans or TIPs required under 23 U.S.C. 134 and 49 U.S.C. 5303 and 5304 for any portion of the area, and do not have projects that are part of the emissions analysis of any MPO's metropolitan transportation plan or TIP. Projects in such areas are instead included only in statewide transportation improvement programs (STIPs) and statewide transportation plans, when appropriate.

Like all newly designated nonattainment areas, the one-year conformity grace period will begin on the effective date of an isolated rural area's initial nonattainment designation. However, because these areas do not have federally required metropolitan transportation plans and TIPs, they are not subject to the frequency requirements for conformity determinations on plans and TIPs specified in § 93.104(b), (c) and (e) of the current rule. Instead, conformity determinations in isolated rural areas are required only when a non-exempt FHWA/FTA project(s) needs funding or approval. Therefore, although the one-year conformity grace period is available to isolated rural areas, no conformity consequences may apply upon the expiration of the one-year grace period because these areas may not have any projects that require funding and approval at that time.

In fact, many isolated rural areas may not have a transportation project in need of federal funding or approval for some time after the one-year grace period has ended, and therefore, will not have to demonstrate conformity before that time. Once the conformity grace period has expired, a conformity determination will only be required in such areas the next time a non-exempt project needs funding or approval. For non-exempt FHWA/FTA projects, a conformity determination is normally required before the National Environmental Policy Act (NEPA) process is completed, since NEPA is typically the first stage requiring approval in a federal project's development. However, isolated rural areas that are newly designated as nonattainment may also be required to demonstrate conformity for subsequent funding and approvals for project phases (

e.g.

, right-of-way acquisition, final design, construction) that occur after the grace period has ended, if these projects have not yet been included in a conformity determination and regional emissions analysis for the relevant pollutant and standard. For more information on the conformity requirements for isolated rural areas, see § 93.109(g) of the current conformity regulation; corresponding discussions on how to demonstrate conformity in isolated rural areas can also be found in the preambles to the November 24, 1993 transportation conformity final rule (58 FR 62207) and the August 15, 1997 final rule (62 FR 43785). Please note that the current rule's § 93.109(g) would become § 93.109(l) under today's proposal, due to other proposed revisions and additions to this regulatory section. The proposed changes to § 93.109 do not change the basic conformity requirements for isolated rural areas.

B. When Does Conformity Stop Applying for the 1-Hour Ozone Standard?

EPA proposed in a separate rulemaking to revoke the 1-hour ozone standard—in whole or in part—one year after the effective date of EPA's 8-hour ozone standard designations (June 2, 2003, 68 FR 32819). Today's conformity proposal is consistent with the revocation options in the June 2003 proposal, but does not seek additional comment on the proposed revocation options.

Clean Air Act section 176(c)(5) requires conformity only in areas that are designated nonattainment or maintenance for a given pollutant and standard. Therefore, under either of the revocation options in EPA's proposed 8-hour ozone implementation rule, conformity for the 1-hour ozone standard would no longer apply in existing 1-hour ozone nonattainment and maintenance areas once the standard and area designations are revoked. The proposed one-year delay in the revocation of the 1-hour ozone standard is linked to the one-year statutory conformity grace period for newly designated 8-hour ozone nonattainment areas. To preserve the progress that areas have made in achieving clean air to date, EPA believes that 1-hour ozone nonattainment and maintenance areas should continue to ensure that transportation activities conform to the existing 1-hour ozone standard until conformity for the new 8-hour ozone standard applies.

During the one-year grace period, areas that are currently subject to the 1-hour ozone standard must continue to adhere to 1-hour conformity requirements. Additionally, areas should consider at what point they will determine conformity for the 8-hour ozone standard. For example, if a conformity determination is made in June 2004, an area may choose to demonstrate conformity for the 1-hour ozone standard and address the 8-hour ozone standard at a later date near the end of the one-year grace period. In contrast, if a conformity determination is made in January 2005, an area may choose to demonstrate conformity for both ozone standards because of the approaching end of the one-year grace period.

Under EPA's June 2003 implementation proposal, when the 1-hour standard is revoked, conformity would no longer apply for either ozone standard in areas that are attaining the 8-hour ozone standard. See EPA's proposed 8-hour implementation rule for more discussion on the proposed options for revoking the 1-hour ozone standard (June 2, 2003; 68 FR 32818-32825).

C. When and for What Ozone Standard Does Conformity Apply in Areas With an Early Action Compact for the 8-Hour Ozone Standard?

Areas that are violating the 8-hour ozone standard but are attaining the 1-hour ozone standard—including 1-hour ozone maintenance areas—were eligible for an Early Action Compact (EAC) as described in EPA's November 14, 2002 memorandum entitled, “Schedule for 8-Hour Ozone Designations and its Effect on Early Action Compacts” and EPA's June 2, 2003 proposal for the implementation of the 8-hour ozone standard (68 FR 32859-32860).

For areas participating in an EAC, EPA plans to provisionally defer the effective date of the area's 8-hour ozone nonattainment designation into the future. The deferral of the 8-hour designation effective date is contingent upon the participating area's adherence to all the terms and milestones of its EAC. If the EAC area attains the 8-hour

ozone standard by December 2007, EPA would take action in Spring 2008 to end the deferred nonattainment designation effective date and replace it with an attainment designation that would become effective shortly thereafter. If, however, an area misses a key EAC milestone, the November 14, 2002 memorandum states that EPA would retract its deferral, and the nonattainment designation would be effective shortly after the missed milestone. Neither today's proposal nor the June 2, 2003 rulemaking take comment on the EAC program itself.

A deferred effective date for 8-hour ozone designations in areas that opted into an EAC has certain implications for when conformity applies for both the 8-hour and 1-hour ozone standards. Consistent with the current conformity rule § 93.102(d) and Clean Air Act section 176(c)(6), conformity for the 8-hour ozone standard would not apply until one year after the effective date of an EAC area's 8-hour nonattainment designation. Therefore, conformity for the 8-hour ozone standard would apply in an EAC area only if the area fails to meet all the terms and milestones of its compact and the nonattainment designation becomes effective. In this case, conformity for the 8-hour standard would be required one year after the effective date of EPA's nonattainment designation that would occur shortly after a missed EAC milestone. Conversely, if the area meets all of the EAC milestones and attains the 8-hour ozone standard by December 2007, conformity for the 8-hour ozone standard would never apply since the area's ultimate effective designation would be attainment for the 8-hour ozone standard.

Conformity for the 1-hour ozone standard will continue to apply in EAC areas that are currently 1-hour ozone maintenance areas, and therefore are required to demonstrate conformity for that standard. For these areas, the effective date of 8-hour designations would be deferred and the 1-hour standard would not be revoked. If a maintenance area meets all of its EAC milestones and attains the 8-hour ozone standard by December 2007, conformity for the 1-hour standard would no longer apply once EPA revokes that standard one year after the effective date of EPA's 8-hour attainment designation (

i.e.

, Spring 2009).

If, however, a 1-hour ozone maintenance area fails to meet a milestone in its EAC, EPA would remove its deferral of the effective date and the area's 8-hour ozone nonattainment designation would become effective shortly after the missed milestone. Under this scenario, conformity for the 1-hour ozone standard would continue to apply for one year after the effective date of EPA's nonattainment designation, at which time the 1-hour ozone standard would be revoked, the one-year conformity grace period would expire and conformity for the 8-hour ozone standard would begin to apply.

IV. General Changes in Interim Emissions Tests

A. Background

Conformity determinations for transportation plans and TIPs as well as transportation projects not from a conforming plan and TIP must include a regional emissions analysis that fulfills certain Clean Air Act provisions. Section 176(c) requires that transportation activities in nonattainment and maintenance areas must not worsen air quality. In addition, transportation activities in ozone and CO areas of higher nonattainment classifications need to contribute emission reductions towards attainment.

The conformity rule provides for several different regional emissions analysis tests that satisfy these Clean Air Act requirements in different situations. Once a SIP with a motor vehicle emissions budget (“budget”) is submitted for an air quality standard and EPA finds the budget adequate or approves it as part of the SIP, conformity is demonstrated using the budget test for that pollutant or precursor, as described in § 93.118 of the conformity rule. Before an adequate or approved SIP budget is available, conformity of the transportation plan, TIP, or project not from a conforming plan and TIP is demonstrated with the interim emissions tests, as described in § 93.119.

Today's proposal outlines several options for completing regional emissions analyses for the new standards before SIP budgets for these standards are available. According to EPA's proposed implementation rule (June 2, 2003, 68 FR 32830-32837), 8-hour ozone nonattainment areas of moderate and above classifications and some areas designated under Clean Air Act subpart 1 would have two or three years from the effective date of designations to submit a SIP (either for attainment or reasonable further progress) with budgets for that standard. Areas classified as marginal and some areas designated under subpart 1 (those with early attainment dates) may not have 8-hour ozone SIP budgets for some time, since their attainment dates would be relatively soon after the date of their 8-hour ozone designations. These areas would only have 8-hour ozone SIP budgets if they voluntarily submitted a control strategy SIP or submitted a maintenance plan for redesignation. In addition, EPA currently anticipates that PM

2.5

nonattainment areas would submit a SIP with budgets within three years of PM

2.5

nonattainment designations.

Therefore, as proposed, conformity would likely apply in all 8-hour ozone and PM

2.5

nonattainment areas before SIP budgets for the new standards are available, and during this time period, interim emissions tests would be used for conformity determinations. It is important to note that EPA has historically called such tests the “emission reduction tests.” However, since the actual reduction of emissions would not always be required in many areas (as described below and in proposed § 93.119), EPA is proposing to change “emission reduction test” to “interim emissions test” throughout the conformity regulation.

The following paragraphs generally describe the proposed changes to the interim emissions tests (under § 93.119). Sections V., VI., and VII. describe the application of these tests in different 8-hour ozone and PM

2.5

areas (under § 93.109).

B. Baseline Year Test for 8-Hour Ozone and PM

2.5

Areas

1. What Are We Proposing?

We are proposing to add the following tests to the conformity rule for use in 8-hour ozone and PM

2.5

nonattainment areas:

• The “less-than-2002 emissions” test, and

• The “no-greater-than-2002 emissions” test.

Under these interim emissions tests, conformity would be demonstrated if the emissions from the proposed transportation system are less than or no greater than 2002 motor vehicle emissions in a given area. Proposed regulatory text for the 2002 baseline year tests can be found in § 93.119.

See

Sections V.-VII. for how these tests are proposed to be applied in 8-hour ozone and PM

2.5

areas.

Although today's action proposes no substantive change to the 1990 baseline year tests for existing areas, § 93.119 has been reorganized to also include the provisions for new 8-hour ozone and PM

2.5

areas.

2. Why Are We Proposing These Changes?

EPA believes that the year 2002 is more appropriate than the year 1990 in

meeting Clean Air Act provisions in new 8-hour ozone and PM

2.5

areas. Under the statute, transportation activities in nonattainment and maintenance areas cannot increase the frequency or severity of air quality violations. EPA selected the year 1990 as the baseline year for nonattainment areas under the existing standards, since that was the baseline year for many requirements in the Clean Air Act Amendments of 1990, including the base year for SIP inventories. It was also the year that the relevant Clean Air Act legislation was enacted.

However, 1990 has little relevance as a baseline year for emissions under the new standards.

Please note that PM

areas can use an alternate baseline year for conformity if the applicable SIP is based on a baseline inventory from a different calendar year (40 CFR 93.119(c)(2)). EPA is not proposing to offer an alternate baseline year for PM

2.5

areas since all PM

2.5

areas should be establishing 2002 baseline SIP inventories.

Therefore, EPA has preliminarily selected 2002 as the baseline year for SIP inventories under the new 8-hour ozone and PM

2.5

standards. EPA's November 18, 2002 memorandum, “2002 Base Year Emission Inventory SIP Planning: 8-hr Ozone, PM

2.5

, and Regional Haze Programs,” identifies 2002 as the anticipated emission inventory base year for the SIP planning process to address both of these pollutants and standards. In addition, EPA's 8-hour ozone implementation rule proposes 2002 as the base year for 8-hour ozone SIP inventories (June 2, 2003, 68 FR 32810). The 2002 SIP inventories would provide the baseline level of motor vehicle emissions in 2002 to complete either proposed baseline year test. In addition, EPA's memo explains that “the selection of 2002 harmonizes dates for other reporting requirements,

e.g.

, EPA's Consolidated Emissions Reporting Rule (CERR) that requires submission of emission inventories every three years; 2002 is one of the required years for such updates.” Therefore, coordinating conformity's baseline with other data collection and inventory requirements would allow state and local governments to use their resources more efficiently.

Under § 93.105(c)(1)(i) of the current rule, the interagency consultation process would be used to determine the latest assumptions and models for generating 2002 motor vehicle emissions to complete either baseline year test. In general, the 2002 baseline year test can be completed with the baseline year SIP's 2002 motor vehicle emissions inventory, if the SIP has been submitted in time for the current conformity determination. If the SIP has not been submitted, conformity could be completed using draft 2002 baseline year emissions from a SIP inventory under development. Alternatively, an MPO, in consultation with state and local air agencies, could develop 2002 baseline year emissions as part of the conformity analysis. Whatever the source, the 2002 baseline year emissions level that is used in conformity must be based on the latest planning assumptions available for the year 2002, the latest emissions model, and appropriate methods for estimating travel and speeds as required by §§ 93.110, 93.111 and 93.122 of the current conformity rule.

C. Build/No-Build Test for Existing and New Nonattainment Areas

1. What Are We Proposing?

EPA is proposing a revised build/no-build test for certain existing and new nonattainment areas. Under the current rule, conformity is demonstrated with the “build-less-than-no-build” test for all ozone, CO, PM

, and NO

areas. The proposal would amend § 93.119 to create the “build-no-greater-than-no-build” test, where conformity would be met if emissions from the proposed transportation system (“build”) were less than or equal to emissions from the existing transportation system (“no-build”).

Under this proposal, the build-no-greater-than-no-build test would be available to the following subset of new and existing areas:

• 8-hour ozone areas of marginal and below classifications,

• 8-hour ozone areas designated nonattainment under Clean Air Act subpart 1,

• All PM

2.5

areas,

• 1-hour ozone areas of marginal and below classifications,

• CO areas of moderate classification with design values less than 12.7 ppm,

• Not classified CO areas,

• All PM

areas, and

• All NO

areas.

Sections V., VI., and VII. of this proposal provide more detail regarding the application of the build/no-build test in various 8-hour ozone and PM

2.5

areas.

For areas that would be using the build-no-greater-than-no-build test, EPA is also proposing to modify § 93.119(e) of the current rule so that a regional emissions analysis would not be necessary for future analysis years where the build (or “action” scenario) and no-build (or “baseline” scenario) contain exactly the same transportation projects and planning assumptions, for the reasons described below. Such a case may occur in smaller areas that do not have projects planned for later years in the regional emissions analysis, and population, land use, economic, and other assumptions do not change between the build and no-build scenarios for those years. Under this proposal, a regional emissions analysis would continue to be required for applicable years where the action and baseline scenarios contain different projects and assumptions.

This proposed change can be found in § 93.119(g)(2) of the proposed regulatory text. This proposal would require that the conformity determination include documentation that a regional emissions analysis is not completed for analysis years in which no new projects are proposed and no change in planning assumptions has occurred.

Finally, § 93.119 is being reorganized in general to accommodate the above and other changes articulated in this proposal for new and existing areas.

2. Why Are We Proposing These Changes?

EPA believes that changing the build/no-build test for certain areas is consistent with Clean Air Act section 176(c)(3)(A)(iii) which specifically requires that transportation plans and TIPs contribute to annual emissions reductions only in the higher classifications of ozone and CO areas. This statutory provision does not apply to any other type of nonattainment area.

Instead, all other areas must demonstrate only that transportation activities do not cause or contribute to new violations, increase the frequency or severity of existing violations, or delay timely attainment, pursuant to Clean Air Act section 176(c)(1)(B). EPA believes that if the “build” is no greater than (

i.e.

, less than or equal to) the “no-build,” that such a demonstration is made, since only an increase in emissions would worsen air quality.

This change to the build/no-build test would make its implementation consistent with the implementation of the baseline year tests: in ozone and CO areas of higher classifications, expected emissions from the proposed transportation system must be less than emissions in the baseline year, while in all other areas, expected emissions must be no greater than emissions in the baseline year. For further discussion of the rationale for how and where the baseline year tests apply, please refer to the preamble to the January 11, 1993 proposed rule (58 FR 3782-3784) and the preamble to the July 9, 1996 proposed rule (61 FR 36116-36117).

Today's proposal would provide flexibility to certain areas by allowing

emissions from the proposed transportation system to be less than or equal to the emissions from the current system, rather than requiring an actual reduction in emissions as is required for ozone and CO areas with higher classifications. Where the Clean Air Act does not require such emission reductions, EPA believes that if transportation activities can be found to conform by producing no adverse impacts on the number and severity of air quality violations, such a demonstration would be consistent with the Clean Air Act requirements.

The proposal would also reduce the resource burden for analysis years where no new projects are proposed to be completed and assumptions do not change. Under the current rule, a regional emissions analysis is required for all analysis years, even if no new projects are proposed for analysis years in the distant future. For such analysis years, the emissions from the build and no-build scenarios contain the same projects and assumptions, and therefore, result in exactly the same level of emissions.

One may argue that it would be obvious that the build-no-greater-than-no-build test is passed without calculating the emissions for such analysis years. Furthermore, the Clean Air Act requirement to not worsen air quality may be met by documenting in the conformity determination that projects, assumptions, and thus emissions would remain the same for affected analysis years. On the other hand, one may argue that a build/no-build regional analysis should still be completed for all analysis years to inform long-term transportation and air quality planning. However if such information is deemed appropriate, analyses could still be done voluntarily. EPA requests comment on this proposed change to the build/no-build analysis year requirements.

D. Test Options for Ozone and CO Nonattaintment Areas of Higher Classifications

1. What Are We Proposing?

EPA is proposing three options that would affect regional emissions analyses before adequate or approved SIP budgets are established in ozone and CO areas of higher nonattainment classifications. Under the current rule, these areas are required to complete both the build-less-than-no-build and less-than-baseline year tests when a conformity determination is completed during this time period. This proposal would affect moderate and above 1-hour and 8-hour ozone areas, moderate CO areas with design values greater than 12.7ppm, and serious CO areas.

EPA requests comment on the following proposed options for these areas:

(1) Complete

both

the build-less-than-no-build

and

less-than-baseline year tests;

(2) Complete

either

the build-less-than-no-build or less-than-baseline year test; or

(3) Require that only one of these tests be met and eliminate the second test as an option altogether.

The proposed regulatory text in § 93.119(b)(1) reflects the first option, although EPA could finalize any one of the three proposed options.

The first option would retain the current conformity rule requirement that such areas use both the current build-less-than-no-build test and the less-than-baseline year test. Under this option, emissions from the proposed transportation system (build) would have to be less than emissions from the existing system (no build) and less than emissions in 1990 (for higher classification 1-hour ozone and CO areas) or 2002 (for higher classification 8-hour ozone areas).

The second proposed option would allow these areas to choose between the current build-less-than-no-build test and the less-than-baseline year test (either 1990 or 2002, as applicable). The final option would require only one test in these areas while eliminating the second test as an option altogether. For example, this option could require the less-than-baseline year test and delete the build/no-build test from the conformity rule as an option for affected areas.

2. Why Are We Proposing These Options?

EPA is interested in exploring alternatives in an effort to provide the most flexible and least burdensome way of meeting statutory requirements. When EPA first promulgated the transportation conformity rule (January 11, 1993, 58 FR 3782), EPA determined that moderate and above 1-hour ozone areas and CO areas of higher classifications would have to meet both the build-less-than-no-build test and the less-than-baseline year test to satisfy both statutory requirements that transportation planning activities not cause or contribute to violations of the standards (Clean Air Act section 176(c)(1)(B)) and that such activities contribute to annual emissions reductions (Clean Air Act section 176(c)(3)(A)(iii)).

The current conformity rule requires higher classification ozone and CO areas to meet both of these tests in the absence of an adequate or approved SIP budget (option 1). For the same reasons described in previous rulemakings,

EPA proposes as its first option to continue these same requirements for current 1-hour ozone and CO and new 8-hour ozone nonattainment areas with higher classifications. EPA believes that the current conformity rule would continue to assist areas in meeting Clean Air Act requirements.

January 11, 1993, proposed conformity rule (58 FR 3782-3784) and the July 9, 1996, proposed rule (61 FR 36116-36117).

However, ten years of experience in implementing the conformity rule has caused EPA to consider whether either the build-less-than-no-build test or less-than-baseline year test (option 2) may also be sufficient to meet both the statutory requirements that transportation activities not contribute to violations and contribute to emissions reductions. First, the build-less-than-no-build test may by itself demonstrate that emissions from the proposed transportation plan would be lower than projected future emissions from the existing planned transportation system, since the build scenario must be less than the no-build scenario. Thus, one might conclude that emissions from the proposed transportation plan contribute to emissions reductions and may not cause or contribute to new violations of the ozone standard.

Alternatively, if emissions are reduced from baseline year levels, then one might conclude that air quality would not be worsened from current levels. The less-than-baseline year test by itself might also demonstrate that implementation of the proposed transportation system may produce actual emissions reductions from the motor vehicle emission baseline year, since emissions must be less than or reduced from the baseline year. Thus, by using only the less-than-baseline year test, the transportation plan may both contribute to emissions reductions and not itself produce emissions that could cause or contribute to any violations. EPA requests comment on this alternative of offering a choice between the build-less-than-no-build and less-than-baseline year tests to meet both statutory conformity requirements, for ozone areas and CO areas of higher classifications.

Further, EPA proposes a third option that such areas be required to meet only one interim emissions test while eliminating the other interim emissions test as an option altogether. As described above for option 2, if it can be concluded that either test is sufficient

for meeting statutory requirements, then retaining only one test in the conformity regulation would also meet the statute. EPA requests comment on this alternate proposal.

V. Regional Conformity Tests in 8-Hour Ozone Areas That Do Not Have 1-Hour Ozone SIPs

A. What Are We Proposing?

EPA is proposing several options for completing regional emissions analyses in 8-hour ozone areas that do not have an existing 1-hour ozone SIP with applicable budgets. These 8-hour ozone areas either were never designated nonattainment under the 1-hour ozone standard or were 1-hour ozone nonattainment areas that for various reasons never submitted a control strategy SIP or maintenance plan with approved or adequate motor vehicle emissions budgets. A regional emissions analysis is the part of a conformity determination that assesses whether the emissions produced by transportation activities are consistent with state and local air quality goals.

1. Conformity After 8-Hour Ozone SIP Budgets Are Adequate or Approved

Once a SIP for the 8-hour ozone standard is submitted with a budget(s) that EPA has found adequate or approved, the budget test would be used in accordance with § 93.118 to complete all applicable regional emissions analyses. Conformity would be demonstrated if the transportation system emissions reflecting the proposed transportation plan, TIP, or project not from a conforming plan and TIP were less than or equal to the motor vehicle emissions budget level defined by the SIP as being consistent with clean air.

The first 8-hour ozone SIP could be a control strategy SIP required by the Clean Air Act (

e.g.

, rate-of-progress SIP or attainment demonstration) or a maintenance plan. The first SIP could also be submitted earlier and demonstrate a significant level of emission reductions from the current level of emissions. For example, an area could submit an early 8-hour ozone SIP that demonstrates a specific percentage of emission reductions (

e.g.

, 5-10%) in the year 2007, from 2002 baseline year emissions. An early 8-hour SIP would include emissions inventories for all emissions sources for the entire 8-hour nonattainment area and would meet applicable requirements for reasonable further progress SIPs. EPA has discussed such an option in the context of its 8-hour ozone implementation rule (June 2, 2003, 68 FR 32822) and the 1997 final conformity rule (August 15, 1997, 62 FR 43798-43799).

Whatever the case, the interim emissions test(s) would no longer apply for conformity purposes for either NO

or VOCs once an 8-hour ozone SIP is submitted and EPA has found adequate or approved its budget(s) for that ozone precursor. Section 93.118 of the current rule describes the budget test; references in § 93.118(a) are being updated in this proposal to be consistent with proposed changes in § 93.109.

EPA encourages nonattainment areas to develop their 8-hour ozone SIPs in consultation with state and local air quality and transportation agencies to facilitate future conformity determinations. EPA Regions are available to assist on an “as needed” basis, including consultation on the development of early 8-hour ozone SIPs.

2. Conformity Before 8-Hour Ozone SIP Budgets Are Adequate or Approved

The following paragraphs outline the options for doing conformity before adequate or approved 8-hour ozone SIP budgets are established in 8-hour ozone areas covered by this section of the proposal.

Marginal and below classifications and subpart 1 areas.

8-hour ozone areas that are not of moderate and above classifications include: 8-hour ozone areas of marginal and below classifications and 8-hour ozone areas designated nonattainment under Clean Air Act subpart 1.

EPA proposes that these 8-hour ozone areas must pass one of the following tests for conformity determinations that occur before adequate or approved 8-hour ozone SIP budgets are in place:

• The build-no-greater-than-no-build test, or

• The no-greater-than-2002 emissions test.

In other words, this proposal would give these 8-hour ozone areas a choice between two interim emissions tests, rather than provide only one test or require that both tests be completed. Conformity would be demonstrated if the transportation system emissions reflecting a proposed transportation plan or TIP were less than or equal to either the emissions from the existing transportation system (no-build) or the level of motor vehicle emissions in 2002.

A discussion of the proposed changes to the interim emissions tests can be found in Section IV. of this proposal. See the proposed regulatory text in § 93.119(b)(2). See EPA's June 2, 2003, proposed implementation rule for the 8-hour ozone standards (68 FR 32811-32816) for more information on the proposal to designate some 8-hour ozone areas under Clean Air Act subpart 1.

Moderate and above classifications.

As described in Section IV.D., EPA proposes three options for regional emissions analyses in moderate and above 8-hour ozone areas that do not have adequate or approved 1-hour ozone SIPs. The options are:

(1) Complete

both

the build-less-than-no-build

and

less-than-baseline year tests;

(2) complete

either

the build-less-than-no-build

less-than-baseline year test; or

(3) require that only one of these tests be met and eliminate the remaining test as an option altogether.

The proposed regulatory text in § 93.119(b)(1) reflects the first option, although EPA could finalize any one of the three proposed options.

3. Options for 8-Hour Ozone Areas That Qualify for EPA's Clean Data Policy

The proposal would also extend the current conformity rule's flexibility for certain 1-hour ozone “clean data areas” to 8-hour ozone areas that are required to meet certain SIP requirements (

e.g.,

moderate and above ozone areas). Today's conformity proposal is also consistent with the clean data option in EPA's proposed 8-hour ozone implementation rule (June 2, 2003, 68 FR 32835).

As background, EPA issued a policy memorandum on May 10, 1995 that addressed SIP requirements in a small number of moderate and above ozone areas (entitled “Reasonable Further Progress, Attainment Demonstrations, and Related Requirements for Ozone Nonattainment Areas Meeting the Ozone National Ambient Air Quality Standard”). Under the May 1995 policy, EPA could declare through rulemaking that a moderate or above 1-hour ozone area was a “clean data area,” if an area had sufficient monitoring data showing attainment of the 1-hour ozone standard. A clean data area is not required to submit any outstanding reasonable further progress or attainment SIPs, since the area is already attaining the standard. Section 93.109(c)(5) of the existing conformity rule allows clean data areas for the 1-hour ozone standard to request that a budget based on the level of motor vehicle emissions in the most recent year of clean data be established through EPA's rulemaking that determines an area to be a clean data area.

Similarly, today's proposal would allow 8-hour ozone areas that have clean data and are required to submit

control strategy SIPs to use one of the following three tests to complete conformity:

• The interim emissions tests, as described above;

• The budget test using the adequate or approved motor vehicle emissions budgets in a submitted 8-hour ozone SIP; or

• The budget test using the motor vehicle emissions level in the most recent year of clean data as budgets, if the state or local air quality agency requests that budgets be established by EPA's clean data rulemaking for the 8-hour ozone standard.

The proposed regulatory text for these options is in § 93.109(d)(5).

This part of the proposal would be provided to moderate and above ozone areas with three years of clean data for the 8-hour ozone standard that have not submitted a maintenance plan and that EPA has determined are not subject to the Clean Air Act's reasonable further progress and attainment demonstration requirements. In addition, some subpart 1 areas would also be covered by this conformity proposal if such areas are required to submit control strategy SIPs, as proposed in the June 2003 ozone implementation rule. Please note that EPA's proposed clean data SIP policy and therefore today's conformity proposal might not be used by any area for the first conformity determination, since newly designated nonattainment areas may not yet have three years of clean data for the 8-hour ozone standard.

4. General Implementation of Regional Tests

The proposal also retains the existing rule's general requirement that regional emissions analyses for ozone areas must address ozone precursors, which are nitrogen oxides (NO

) and volatile organic compounds (VOCs) (40 CFR 93.102(b)(2)(i)). All proposed interim emissions test options would be required to address both VOC and NO

precursors, unless EPA determines that additional reductions of NO

would not contribute to attainment for the 8-hour ozone standard and issues a NO

waiver under Clean Air Action section 182(f). This is consistent with the current conformity rule, although the proposal moves these provisions to § 93.119(f) due to reorganization of § 93.119. Finally, the proposal retains the current rule's provision that the interim emissions test(s) be completed for NO

if a reasonable further progress SIP is submitted with only a budget for VOCs (e.g., a 15% SIP). See § 93.109(d)(3) for this proposed regulatory text.

The consultation process should be used to determine the models and assumptions for completing either the interim emissions tests or the budget test, as required by § 93.105(c)(1)(i) of the current rule. See the proposed regulatory text in § 93.109(d) for a general overview of when the budget test and interim emissions tests would apply in 8-hour ozone nonattainment areas without 1-hour ozone SIP budgets.

B. Why Are We Proposing These Options?

EPA has been told by some stakeholders that it is reasonable and credible to provide 8-hour ozone areas with the same flexibility that applies under the 1-hour ozone standard. To that end, EPA has proposed that 8-hour ozone areas with fewer SIP requirements (e.g., marginal and subpart 1 areas) continue to have the choice offered by the current rule between the baseline year and build/no-build tests. EPA gave this choice to 1-hour ozone areas as described in the preamble to a previous proposal (July 9, 1996, 61 FR 36116-36117). EPA continues to believe that allowing these areas a choice of conformity tests during the time period before adequate or approved 8-hour ozone SIP budgets are in place is environmentally protective and meets the statutory requirements.

As noted above, we are also considering three options for moderate and above ozone areas to ensure that every flexibility is provided to new 8-hour ozone areas while achieving environmental benefits. Please see EPA's rationale for these proposed options in Section IV.D.2.

EPA is also responding to stakeholder requests that the rule continue to provide more choices to areas that would qualify for EPA's proposed 8-hour ozone clean data policy. If the proposed clean data policy is included in the final 8-hour ozone implementation rule, EPA proposes to also include the proposed conformity options for such areas in the final conformity rule for the new standards. See EPA's previous discussion and rationale for the clean data options from the preamble to the 1996 proposal and 1997 final rules (July 9, 1996, 61 FR 36116; and August 15, 1997, 62 FR 43784-43785, respectively).

VI. Regional Conformity Tests in 8-Hour Ozone Areas That Have 1-Hour Ozone SIPs

A. What Are We Proposing?

EPA is proposing several options for completing regional emissions analyses in 8-hour ozone areas that have an existing 1-hour ozone SIP that covers either some or all of the 8-hour ozone nonattainment area.

1. Conformity After 8-Hour Ozone SIP Budgets Are Adequate or Approved

Once a SIP for the 8-hour ozone standard is submitted with budget(s) that EPA has found adequate or approved, the budget test would be used to complete the regional emissions analysis. The first 8-hour ozone SIP could be a control strategy SIP required by the Clean Air Act (

e.g.

, rate-of-progress SIP or attainment demonstration). The first SIP could also be submitted earlier and demonstrate a significant level of emission reductions from the current level of emissions, as described in Section V.A.1. Interim emissions tests and/or any existing 1-hour ozone SIP budgets (as described below) would no longer be used for conformity for either NO

or VOCs once an adequate or approved 8-hour ozone SIP is established for such a precursor. State, local, and Federal air quality and transportation agencies should consult on the development of 8-hour ozone SIPs as appropriate.

2. Conformity Before 8-Hour Ozone SIP Budgets Are Adequate or Approved

The following paragraphs outline the options for determining conformity before adequate or approved 8-hour ozone SIP budgets are in place in 8-hour ozone areas with existing 1-hour ozone SIP budgets. EPA is proposing that these 8-hour ozone areas be able to select one test option from among a menu of test options for completing the regional emissions analysis requirement, rather than be required to complete a specific test(s).

Summary of Options:

The following table summarizes the menu of proposed options, based on the placement of 1-hour and 8-hour ozone nonattainment boundaries:

Boundary scenario

Menu of options

Proposed regulatory text

8-hour area = 1-hour area

Interim emissions test(s) OR

§ 93.109(e)(2)(i) OR

Budget test using 1-hour budget(s)

§ 93.109(e)(2)(ii)(A).

8-hour area < 1-hour area

Interim emissions test(s) OR

§ 93.109(e)(2)(i) OR

Budget test for 1-hour area (with 1-hour budget(s)) OR

§ 93.109(e)(2)(ii)(B) OR

Budget test for 8-hour area (with applicable subset of 1-hour budget(s))

§ 93.109(e)(2)(ii)(B).

8-hour area > 1-hour area

Interim emissions test(s) OR

§ 93.109(e)(2)(i) OR

Budget test (with 1-hour budget(s)) PLUS Interim emissions test(s) (for remainder of 8-hour area)

§ 93.109(e)(2)(ii)(C).

Portions of 8-hour and 1-hour areas overlap

Interim emissions test(s) OR

§ 93.109(e)(2)(i) OR

Budget test (with applicable subset of areas 1-hour budget(s)) PLUS Interim emissions test(s) (for remainder of 8-hour area)

§ 93.109(e)(2)(ii)(C)

EPA has posted pictures of hypothetical boundary scenarios for further clarification on the transportation conformity website listed in Section I.B.2.

Please note that the proposed options are for completing conformity under the 8-hour ozone standard. EPA is proposing that the budget test with existing 1-hour ozone SIP budgets be used as a test option (or proxy) for the 8-hour ozone standard, rather than the 1-hour ozone standard. Conformity for the 1-hour and 8-hour ozone standards would not apply at the same time, as proposed in EPA's 8-hour ozone implementation rule (June 2, 2003, 68 FR 32819). In addition, for the reasons explained below, EPA is not proposing that 8-hour ozone areas must use their 1-hour ozone budgets if such budgets exist; we are proposing only that the budget test using the 1-hour ozone budgets would be an option as appropriate in addition to the interim emissions test(s).

The following paragraphs describe the above table in further detail as well as sub-options that are being proposed for some boundary scenarios. For all scenarios, once an area selects a particular test(s), EPA proposes that it must be used consistently for all regional analysis years.

Scenario where 8-hour and 1-hour ozone boundaries are exactly the same.

In this case, the 8-hour and 1-hour ozone boundaries cover exactly the same geographic area. EPA proposes to require such areas meet one of the following:

• The interim emissions tests, depending upon an area's classification or designation; or

• The budget test using existing adequate or approved 1-hour ozone SIP budgets.

See

Section V. for further description of which interim emissions test(s) would apply in a given 8-hour ozone area.

Scenario where the 8-hour ozone boundary is smaller than and within the 1-hour ozone boundary.

In this case, the 8-hour nonattainment area is smaller than and completely encompassed by the 1-hour nonattainment boundary. Again, EPA proposes to require such areas meet one of the following:

• The interim emissions tests, depending upon an area's classification or designation;

• The budget test using the subset or portion of existing adequate or approved 1-hour ozone SIP budgets that overlaps with the 8-hour nonattainment area; or

• The budget test using the existing adequate or approved 1-hour ozone SIP budgets for the entire 1-hour nonattainment area (any additional reductions must come from the 8-hour nonattainment area, as described below).

EPA also requests comment on when it would be feasible and appropriate to allow an area to use a subset or portion of a 1-hour ozone SIP budget for 8-hour ozone conformity. Such a test option requires an area to subtract from the 1-hour ozone budget and conformity analysis those emissions that are not produced in the 8-hour ozone area. For example, this would be straightforward if the on-road mobile inventory for the 1-hour ozone SIP budget is calculated by county, and the portion to be subtracted is a specific county that is not part of the 8-hour ozone area. However, this may not be appropriate in the case where the SIP does not clearly specify the amount of emissions in the portion of the 1-hour ozone area not covered by the 8-hour ozone area. The consultation process would be used to determine when using a portion of a 1-hour ozone SIP budget is appropriate, and if so, how deriving such a portion would be accomplished. EPA requests other examples for when using a portion of a 1-hour ozone SIP budget would be feasible and appropriate.

In addition, EPA notes that adjusting the 1-hour ozone budgets for purposes of conducting 8-hour ozone conformity analyses would be legally appropriate since any 1-hour ozone SIP demonstrations and budgets would only be used as a proxy for the 8-hour ozone standard and would themselves no longer be for an applicable standard (

i.e.

, since the 1-hour ozone standard would be revoked under EPA's proposed 8-hour ozone implementation rule).

A conformity determination based on the entire 1-hour ozone budget would include a comparison between the on-road regional emissions produced in the entire 1-hour ozone area and existing 1-hour ozone budgets. However, if additional reductions are required to meet conformity, EPA proposes that such reductions could only be obtained within the 8-hour ozone nonattainment area, since the conformity determination would be for the 8-hour ozone standard.

Scenarios where the 8-hour ozone boundary is larger than or overlaps with a portion of the 1-hour ozone boundary.

This part of the proposal covers the third and fourth scenarios listed in the above table in this section. The third scenario would result if an entire 1-hour ozone nonattainment area is within a larger 8-hour ozone nonattainment area. The fourth scenario would result if 1-hour and 8-hour ozone nonattainment boundaries partially overlap. In both types of 8-hour ozone areas, the 1-hour ozone budgets would not cover the entire 8-hour nonattainment area. Therefore, existing 1-hour ozone budgets cannot be the sole test of conformity under the 8-hour ozone standard in these scenarios, since a conformity determination must include a regional emissions analysis that covers the entire 8-hour ozone nonattainment area.

EPA is proposing that areas in these scenarios meet one of the following:

• The applicable interim emissions tests for the entire 8-hour ozone area; or

• The budget test based on the 1-hour ozone budget(s) for the 1-hour ozone area or relevant subset or portion of the 1-hour ozone area, plus the interim emissions test(s) for the remaining portion of the 8-hour ozone nonattainment area.

As stated above, once an area selects a particular test(s), EPA proposes that it must be used consistently for all regional analysis years.

For example, a marginal or below 8-hour ozone area that is larger than the

1-hour ozone area (third scenario) could choose to complete the budget test for the 1-hour ozone nonattainment area and the no-greater-than-2002 test for the remaining portion of the 8-hour ozone area for the attainment year, an intermediate year, and the last year of the transportation plan. EPA is not proposing to require such an area to complete the interim emissions test for the entire 8-hour ozone nonattainment area in all cases, in addition to the budget test with the 1-hour ozone SIP. EPA acknowledges that there may be cases where it is difficult to separately model the remaining portion of the 8-hour ozone area,

e.g.

, in an area where the remaining 8-hour ozone area is a ring of counties around the 1-hour ozone area. However, in this case, an area could always choose to complete only the interim emissions test(s) for the entire 8-hour ozone area, rather than the budget test with 1-hour ozone SIP budgets for the 1-hour ozone area.

For areas covered by the third boundary scenario in the above table where the 8-hour ozone area is larger than the 1-hour ozone area, the budget test would be completed for the entire 1-hour ozone area, as is done for conformity determinations for the 1-hour ozone standard. For areas covered by the fourth scenario where 8-hour and 1-hour ozone areas overlap, the budget test would only be done for the portion of the 1-hour ozone area and budgets that overlap with the 8-hour ozone area. EPA acknowledges that the budget test with a portion of a 1-hour ozone budget may be difficult to implement in many areas, since it assumes that areas will be able to determine easily the amount of budget emissions that are in the relevant portion. EPA requests examples for when using a portion of a 1-hour ozone budget would be appropriate and how to calculate such a portion. The consultation process would be used to determine whether the budget test for the fourth scenario is appropriate and if so, how it should be implemented.

Finally, EPA notes that the consultation process should be used to determine which analysis years should be selected for regional emissions analyses where the budget test and interim emissions tests are used. Sections 93.118(d) and 93.119(e) of the current conformity rule require similar analysis years for modeling in the last year of the transportation plan and for any intermediate years for both budget and interim emissions tests. However, the analysis years for the short-term may be different for the budget test and interim emissions tests in some cases. For example, § 93.118 requires modeling for the budget test to be completed for the attainment year if it is within the timeframe of the transportation plan; § 93.119 requires the first analysis year for the interim emissions tests to be within the first five years of the transportation plan. The consultation process can be used to pick analysis years that would satisfy both the budget and interim emissions test requirements for areas using both tests prior to adequate or approved 8-hour ozone SIP budgets being established.

3. Options for 8-hour Ozone Areas That Qualify for EPA's Clean Data Policy

As described in Section V.A.3., today's conformity proposal would also extend the current rule's flexibility for certain 1-hour ozone areas to 8-hour ozone areas that are covered by EPA's June 2, 2003 proposal (68 FR 32835). The June 2003 proposal extends the existing 1-hour ozone clean data policy for the SIP process to future 8-hour ozone areas that are required to submit control strategy SIPs.

Specifically, we are proposing to require such 8-hour ozone areas with adequate or approved 1-hour ozone SIP budgets to meet one of the following four options to complete conformity:

• The interim emissions tests, as described in Section V.;

• The budget test using the adequate motor vehicle emissions budgets in a submitted control strategy SIP for the 8-hour ozone standard;

• The budget and/or interim emissions tests using existing 1-hour ozone SIP budgets and/or applicable interim emissions tests, as described in A.3. of this section for different scenarios of 1-hour and 8-hour ozone nonattainment boundaries; or

• The budget test using the motor vehicle emissions level in the most recent year of clean data as budgets, if such budgets are established by the EPA rulemaking that determines an area to have clean data for the 8-hour ozone standard.

See

the proposed regulatory text for these options in § 93.109(e)(4).

4. General Implementation of Regional Tests

The proposal also retains the existing rule's general requirements that regional emissions analyses for ozone areas must address NO

and VOC precursors (40 CFR 93.102(b)(2)(i)). All proposed interim emissions test options would be required to address both precursors, unless EPA determines that additional reductions of NO

would not contribute to attainment for the 8-hour ozone standard and issues a NO

if a reasonable further progress SIP is submitted with only a budget for VOCs (

e.g.

, a 15% SIP).

See

§ 93.109(e)(3) for this proposed regulatory text.

The consultation process should be used to determine the models and assumptions for completing the interim emissions tests and/or the budget test, as required by § 93.105(c)(1)(i) of the current rule. The consultation process can also be used to select the conformity test(s) before 8-hour ozone SIPs are submitted. See the proposed regulatory text in § 93.109(e) for a general overview of when the budget test and interim emissions tests apply in 8-hour ozone nonattainment areas with 1-hour ozone SIP budgets.

B. Why Are We Proposing These Options?

EPA has received stakeholder input asking EPA to provide 8-hour ozone areas with conformity flexibility in the time period before 8-hour ozone SIPs are established. In response, EPA is proposing a menu of options for 8-hour ozone areas that have existing 1-hour ozone SIP budgets, rather than requiring only one conformity test be used. Allowing areas to choose between the interim emissions tests and/or the budget test based on 1-hour ozone SIPs would accommodate the many different boundary scenarios described in VI.A.2.

EPA has previously found that the interim emissions tests are sufficient for meeting the Clean Air Act requirements for a given standard before a SIP with adequate budgets is in place for that standard. As discussed in Sections IV. and V. of this proposal, EPA believes that Clean Air Act sections 176(c)(1) and (c)(3)(A)(iii) can be met through only one or a combination of interim emissions tests, depending upon an area's classification.

Our proposal to allow areas to use the 1-hour ozone budgets before 8-hour ozone budgets are available does not mean that areas would be determining conformity for the 1-hour ozone standard. As articulated in the proposed 8-hour ozone implementation rule, EPA is proposing that conformity for only one ozone standard apply at a time (June 2, 2003, 68 FR 32823-32824).

We are proposing to offer the budget test as a choice because we think that many 1-hour ozone budgets provide as good an analytical test as the other tests that exist or are proposed for use before

8-hour ozone budgets are available: the build/no-build and baseline year tests. In general, EPA believes the 1-hour ozone budgets may be an appropriate test like the build/no-build test, because the 1-hour ozone VOC and NO

budgets that an area has represent a reduction in emissions that is consistent with the applicable SIP for that standard. Although the 8-hour ozone standard is more stringent than the 1-hour ozone standard, many 1-hour ozone budgets have in fact served to reduce emissions over time. For example, the Clean Air Act requires that transportation plans and TIPs reduce emissions in the higher classifications of ozone and CO areas before a SIP for a given pollutant and standard is developed. We believe that the budget test using 1-hour ozone budgets may meet this requirement at least as well as the build/no-build test.

EPA also believes that the 1-hour ozone budgets may be comparable to the baseline year test for conformity under the 8-hour ozone standard. The baseline year test could actually be thought of as a type of budget test before 8-hour ozone budgets are established: emissions in the year 2002 become the ceiling on emissions, a defacto budget. The budgets in 1-hour ozone SIPs are at least as good as the 2002 baseline year test if areas are meeting them when they are designated for the 8-hour ozone standard. In the case where 2002 emissions are higher than established 1-hour ozone budgets, the budget test would actually be a more conservative test. However, in the case where 2002 emissions are lower than the 1-hour ozone budgets, the budgets should still be a valid test since they provide for attainment of the 1-hour ozone standard. In other words, consistency with the 1-hour budgets would have resulted in a certain level of emissions at the time areas were designated for the 8-hour ozone standard. An area's designation as a nonattainment area for the 8-hour ozone standard would be based on its air quality monitoring data for the years 2001-2003. Therefore, EPA does not anticipate that many areas will have 2002 emissions significantly lower than 1-hour budgets since areas would not have likely put control measures in place by 2002 that would result in lower emissions for that year. We believe that consistency with the 1-hour ozone budgets would assure an emissions level that is in line with the baseline year test, since the baseline year is 2002.

However, EPA does not believe that 8-hour ozone areas that have 1-hour ozone budgets must use these budgets for conformity prior to the development of 8-hour ozone budgets. Although an area could conclude through the consultation process that use of a 1-hour ozone budget would be appropriate, there may be many cases where the 1-hour ozone budget would not provide the best test for conformity to the 8-hour ozone standard. For instance, 1-hour ozone budgets could be for a year different than the year for which 8-hour ozone conformity is being demonstrated. For example, 1-hour budgets could be from a rate-of-progress SIP (

e.g.

, a 15% plan) for a past milestone year, such as 1996, that is no longer relevant to projected emissions in the post-2002 period for the 8-hour ozone standard. In contrast, an area may only have a 1-hour ozone maintenance plan with budgets for a year beyond the 8-hour ozone attainment year. The planning assumptions (such as VMT, vehicle fleet characteristics, speeds) underlying the 1-hour budget may also be significantly out-of-date.

Thus, although it is appropriate to offer areas the opportunity to use 1-hour ozone budgets, EPA believes that they should not be mandated and that the consultation process should be used to select the most appropriate test for a particular area prior to the development of adequate or approved 8-hour ozone SIP budgets. EPA requests comment on this proposal to allow areas to use applicable 1-hour ozone budgets to demonstrate conformity prior to the development of 8-hour ozone budgets, and to use the consultation process to determine whether such budgets should be used.

Finally, today's proposal responds to stakeholder requests that the rule continue to offer more choices to new ozone areas that would qualify for EPA's proposed 8-hour ozone clean data policy. If the proposed 8-hour ozone clean data policy is included in the final 8-hour ozone implementation rule, EPA would also include the proposed conformity options for such areas in the final conformity rule for the new standards. See EPA's previous discussion and rationale for the clean data options in the preamble to the 1996 proposal and 1997 final rules (July 9, 1996, 61 FR 36116, and August 15, 1997, 62 FR 43785, respectively).

VII. Regional Conformity Tests in PM

2.5

Areas

A. What Are We Proposing?

EPA proposes that the budget test would be used to complete a regional emissions analysis once a PM

2.5

SIP is submitted with budget(s) that EPA has found adequate or approved. Although the first PM

2.5

SIP may be an attainment demonstration, PM

2.5

nonattainment areas “are free to establish, through the SIP process, a motor vehicle emissions budget [or budgets] that addresses the new NAAQS in advance of a complete SIP attainment demonstration. That is, a state could submit a motor vehicle emissions budget that does not demonstrate attainment but is consistent with projections and commitments to control measures and achieves some progress towards attainment.” (August 15, 1997, 62 FR 43798-43799). Such a SIP would include inventories for all emissions sources. EPA encourages nonattainment areas to develop their PM

2.5

SIPs in consultation with Federal, state, and local air quality and transportation agencies as appropriate.

EPA is proposing that PM

2.5

nonattainment areas meet one of the following interim emissions tests for conformity determinations conducted before adequate or approved PM

2.5

SIP budgets are established:

• The build-no-greater-than-no-build test, or

• The no-greater-than-2002 emissions test.

This proposal would allow PM

2.5

nonattainment areas to choose between the two interim emissions tests, rather than require that only one test or both tests be completed. Conformity would be demonstrated if the transportation system emissions reflecting the proposed plan or TIP (build) were less than or equal to either the emissions from the existing transportation system (no-build) or the level of motor vehicle emissions in 2002. A discussion of the proposed changes to the interim emissions tests can be found in Section IV.

The proposal would require that regional emissions analyses always be completed for directly emitted PM

2.5

from motor vehicle tailpipe, brake wear, and tire wear emissions. Once a SIP is submitted, the budget test would also be completed for any PM

2.5

precursor for which an adequate or approved budget is established. Prior to adequate or approved SIP budgets, an interim emissions test would be completed for each applicable PM

2.5

precursor, as described in Section VIII. Sections IX. and X. describe proposed options for when regional emissions analyses would include direct PM

2.5

emissions from re-entrained road dust and construction-related dust.

The consultation process should be used to determine the models and assumptions for completing any regional emissions analysis, as required by § 93.105(c)(1)(i). See the proposed regulatory text in § 93.109(i) for a general overview of when the budget test and interim emissions tests apply in

2.5

areas, and § 93.119(e) for a description of the interim emissions tests for PM

2.5

nonattainment areas.

B. Why Are We Proposing These Options?

We believe that the proposal addresses the concerns of many stakeholders by providing flexibility before adequate or approved PM

2.5

SIP budgets are established. While many PM

2.5

areas will have prior conformity experience with different pollutants, others will be doing conformity for the first time. In either case, the conformity process provides an important opportunity to begin addressing transportation-related PM

2.5

emissions early to ensure that air quality is not worsened before SIPs are submitted. Proposing a choice of interim emissions tests before SIPs are submitted addresses the desire for flexibility and environmental protection.

EPA has previously determined that only ozone and CO areas of higher classifications are required to satisfy both statutory requirements that transportation planning activities not cause or contribute to violations of the standards (Clean Air Act section 176(c)(1)(B)) and that such activities contribute to annual emissions reductions (Clean Air Act section 176(c)(3)(A)(iii)) (January 11, 1993 proposed rule, 58 FR 3782-3783). EPA continues to believe that Clean Air Act section 176(c)(3)(A)(iii) does not apply to any other areas, including PM

2.5

areas; only Clean Air Act section 176(c)(1)(B) applies to these areas.

To that end, the current conformity rule already allows many areas to conform based on only one interim emissions test if transportation emissions are consistent with current air quality expectations, rather than having to complete two tests and contribute further reductions towards attainment. Today's proposal continues to apply this same test structure and rationale to PM

2.5

areas.

VIII. Consideration of Direct PM

2.5

and PM

2.5

Precursors in Regional Emissions Analyses

A. What Are We Proposing?

We are proposing to require that all regional emissions analyses in PM

2.5

nonattainment and maintenance areas consider all sources of directly emitted PM

2.5

motor vehicle emissions from the tailpipe, brake wear, and tire wear. Proposed regulatory text can be found in § 93.102(b)(1).

See

Sections IX. and X. for the proposed options for including direct PM

2.5

from re-entrained road dust and construction-related dust in conformity analyses.

This proposal would also add potential transportation-related PM

2.5

precursors—NO

, VOCs, sulfur oxides (SO

), and ammonia (NH

)-for consideration in the conformity process. Once a PM

2.5

SIP is submitted, a regional emissions analysis would be required for a given precursor if the SIP establishes an adequate or approved budget for that particular precursor.

The following two options address how the various PM

2.5

precursors would be considered in conformity determinations conducted before adequate or approved PM

2.5

SIP budgets are established, for the reasons explained below. EPA is proposing regulatory text in §§ 93.102(b)(2) and 93.119(f) for both of these options. We are providing the regulatory text for both options to maximize the public's opportunity to provide meaningful comments.

The first proposed option would require regional emissions analyses for NO

and VOC precursors in all areas, unless the State air agency or the EPA Regional Administrator makes a finding that one or both of these specific precursors

are not a significant

contributor

to the PM

2.5

air quality problem in a given area. Regional emissions analyses would not be required for SO

and NH

before an adequate or approved SIP budget for such precursors is established, unless the State or EPA makes a finding that on-road emissions of one or both of these precursors

is a significant contributor.

Under the first option, the MPO and DOT would document in their conformity determinations when regional emissions analyses are not being conducted when EPA or the State has determined NO

or VOCs to be insignificant.

The public would be notified of when NO

or VOC is considered insignificant through the documentation in a conformity determination under the first option.

EPA's second option would only require regional emissions analyses for one or more PM

2.5

precursors (

i.e.

, NO

, VOC, SO

and NH

) before adequate or approved PM

2.5

SIPs have been established if the State or EPA makes a finding that one or more of these precursors

are significant contributors

to the PM

2.5

air quality problem in a given area.

A State air agency or EPA finding of significance or insignificance (a “significance finding”) would be based on criteria similar to the general criteria currently used by EPA to evaluate SIPs that claim on-road emissions are insignificant for a given pollutant or precursor. EPA's existing policy for insignificance serves as the basis for today's proposal, as described in Section XIV.B. of this notice. The following criteria should be considered in making significance findings for PM

2.5

precursors under either proposed option: the contribution of on-road emissions of the precursor to the total 2002 baseline SIP inventory; the current state of air quality for the area; the results of speciation monitoring for the area; the likelihood of future motor vehicle control measures for a given precursor; and projections of future on-road emissions of the precursor. The State air agency or EPA Regional Administrator would determine significance or insignificance of motor vehicle emissions in a given area on a case-by-case basis.

Under either option, a significance finding should be made only after discussions with the interagency consultation group for the PM

2.5

nonattainment area. These discussions should include a review of the available data being considered to support the significance finding. Interagency consultation also ensures that all of the relevant agencies are aware that such a finding is being considered. It is important to provide transportation agencies with adequate notice of which, if any, precursors they may need to address in conformity analyses. A significance finding would be made through a letter to the relevant State and local air quality and transportation agencies, MPO(s), DOT and EPA (in the case of a State air agency finding).

EPA notes that any significance finding made prior to the SIP should not be viewed as the ultimate determination of the significance of precursor emissions in a given area. State and local agencies may find through the SIP development process that emissions of one or more precursors are significant, even if a precursor had previously been considered insignificant. In such a case, the PM

2.5

SIP would establish motor vehicle emissions budgets and significant precursors would be included in subsequent conformity analyses.

To calculate emission factors for direct PM

2.5

from motor vehicles and PM

2.5

precursors areas in all states except California would use the latest EPA-approved motor vehicle emissions factor model (currently MOBILE6). PM

2.5

nonattainment and maintenance areas in California should use EMFAC2002 or a more recently EPA-approved model. It should be noted that EMFAC2002 currently does not calculate emissions factors for NH

However, EPA understands that California is working on a revision to EMFAC that should enable the model to calculate emissions factors for NH

. A schedule for completing the necessary revisions has not been established. As a practical matter, conformity for NH

would not be required in California until there is an acceptable method for estimating such emissions, since a method would be needed to estimate current or future NH

emissions for either a significance finding or SIP motor vehicle emissions budget.

Including any precursors in regional emissions analyses prior to the submission of a SIP should not result in any additional transportation or emissions modeling work since the nonattainment areas will already be estimating vehicle miles traveled (VMT) from transportation activities for the direct PM

2.5

regional emissions analysis. In addition, EPA's upcoming MOBILE6.2 and California's EMFAC2002 are designed to generate emissions factors for direct PM

2.5

and PM

2.5

precursors in the same modeling run. Therefore, if any area is already generating PM

2.5

emissions factors, precursor estimates would be available without any additional effort, with the possible exception of NH

estimates in California, as indicated above.

B. Why Are We Proposing These Options?

Section 176(c)(1)(B) of the Clean Air Act requires that federal funding and approval be given only to transportation activities that are consistent with state and local air quality goals. To fulfill this requirement with respect to PM

2.5

, EPA is proposing that transportation conformity determinations consider PM

2.5

and its precursors if they are significant contributors to an area's PM

2.5

air quality problem.

EPA anticipates that in most nonattainment and maintenance areas direct PM

2.5

emissions would be an important contributor to the PM

2.5

air quality problem, and therefore, we are proposing that direct PM

2.5

emissions from motor vehicles be included in all conformity analyses. In addition, EPA's proposal to require conformity to all relevant budgets established in the PM

2.5

SIP is consistent with the Clean Air Act in that transportation activities must conform to the air quality goals established and estimates of future emissions in the SIP for a given area.

EPA has proposed NO

, VOCs, SO

, and NH3 as potential transportation-related PM

2.5

precursors since all of these precursors are emitted from on-road motor vehicles. Based on data collected from monitoring sites in the national speciation trends network,

secondary particles from precursors commonly account for over half of the total fine particle mass from all emissions sources measured at these sites. Therefore, we expect that areas may need to address on-road emissions of relevant precursors (

i.e.

, NO

, VOC, SO

and NH

) in their SIPs and in conformity.

The speciation trends network consists of over 50 monitoring sites in urban areas and provides nationally consistent data on PM

2.5

constituents including nitrates, elemental carbon, organic carbon and sulfates.

EPA believes that the two proposed options would allow for the consideration of the four potential precursors in conformity prior to PM

2.5

SIPs when such precursors are significant. However, they differ in terms of whether a NO

or VOC precursor is presumed to be significant and considered in conformity from the start, or whether a finding of significance is necessary before a precursor is addressed. The proposed options attempt to strike a balance between: (1) Expeditiously addressing transportation-related emissions that could exacerbate the PM

2.5

air quality problem before a SIP is established, and (2) targeting conformity requirements in PM

2.5

areas in an efficient and reasonable manner. As described above, the proposed options would only require SO

and NH

analyses if either precursor was found to be significant before a PM

2.5

SIP.

For example, the first proposed option is more environmentally conservative by requiring that NO

and VOC conformity analyses be included in all areas initially. If EPA finds that in most areas motor vehicle emissions of these precursors are significant contributors to PM

2.5

air quality problems, it may warrant the first option's more straightforward approach to meeting Clean Air Act requirements. In other words, areas would begin addressing NO

and VOC emissions upon designation under the first option, without having a separate state or EPA finding of significance. This option is similar to the current rule's requirement that ozone areas must address NO

and VOC precursors.

On the other hand, the second proposed option is consistent with the current rule's approach for PM10 precursors, where NO

and VOC conformity analyses are only conducted prior to PM

SIPs if the State or EPA finds either precursor significant (40 CFR 93.102(b)(2)(iii)). EPA finalized this approach in the November 24, 1993 conformity rule because at that time secondary formation appeared to be less important for the PM

NAAQS in general, although some PM

areas have since established NO

and/or VOC SIP budgets.

The second proposed option would account for regional variability and target conformity analyses where EPA or the state determine NO

and VOC precursors to be significant to an area's PM

2.5

problem. Although we know that NO

and VOC precursors generally play a more important role in PM

2.5

formation, we continue to gather more specific information on the significance of these precursors in different parts of the country. One could argue that it may be more appropriate to focus scarce state and local efforts on NO

and VOC precursors only when they are determined to be significant, especially if adopting control measures early in conformity may prove not to be necessary in the PM

2.5

SIPs.

The following paragraphs present information on current speciated air quality data and on-road emissions of the precursors that contribute to the formation of secondary particles. The information is intended to illustrate what we know about PM

2.5

precursor emissions and air quality. This type of information is relevant to deciding whether or not to initially require that a precursor be considered in conformity before a more thorough evaluation is conducted through the SIP development process. The emission inventory data used in the following discussion is for 372 potential nonattainment counties based on 1999-2001 ambient data.

Summaries of the air quality and emissions inventory data discussed below are available in the docket for this rulemaking. More detailed air quality emission inventory data is available on the EPA Web site at

http://www.emissionsonline.org/nei99v3/index.htm.

The public is welcome to submit additional data on the importance of including PM

2.5

precursors in conformity before SIPs are established.

Through this data, we identified 129 counties that have violating monitors for PM

2.5

. EPA is currently reviewing 2000-2002 ambient data which may affect the numbers discussed in today's proposal.

precursor emissions.

On-road sources accounted for approximately 40% of total NO

emissions in 1999 in the 372 potential nonattainment counties. Based on data collected from monitoring sites in the national speciation trends network, nitrates—which result from reactions involving NO

—make up between 5 and 40% of the total PM

2.5

constructed mass. The areas with the highest percentages of nitrates are in California and parts of the

Midwest. The areas with lowest percentages tend to be in the southeast, where nitrates make up only 5 to 10% of the total PM

2.5

constructed mass.

The 2003 NARSTO-PM report (“Particulate Matter Science for Policy Makers: A NARSTO Assessment,” February 2003) states, “Nitrates represent a major fraction of the PM

2.5

mass measured in some locations, though the management of the nitrate fraction via NO

emission reductions needs to be addressed in combination with VOCs, NH

and SO

. This must be done in consideration of the relationship between nitrate production and local or regional ozone formation.” The report also states, “Reductions of NO

, VOCs, and associated NH

throughout the year in and around large urban areas may be important in the East as well as the West to bring down the nitrate contributions to the 24-hr and/or annual PM averages. While summer nitrate concentrations in eastern North America are low in comparison with other PM

2.5

components, higher winter nitrate concentrations occur in northern urban areas.” The report goes on to indicate that the application of chemical transport models and comprehensive air quality monitoring will be useful in determining how best to address nitrates.

A number of factors should be taken into account when considering the two options for addressing NO

as presented above. The first proposed option (which specifies that conformity demonstrations during the pre-SIP period must cover NO

unless a finding is made that NO

not

a significant contributor to the area's PM

2.5

problem) is supported by the fact that on a national basis, NO

is clearly a significant contributor to the PM

2.5

problem, that nitrates constitute some portion of the problem in each metropolitan area, and that on-road sources are significant contributors of NO

emissions in the potential nonattainment counties. In addition, assuming further sulfur dioxide reductions are required in order to attain the PM

2.5

standards, certain areas may see an increase in nitrate formation as sulfur dioxide emissions decline due to the reaction of ammonia with NO

, which in relative terms would be more “available” for such reactions. In order to minimize this “NO

disbenefit” situation, NO

emissions should be further reduced at the same time. These factors may argue that a more environmentally conservative approach is needed to meet the Clean Air Act conformity provisions, and that NO

should be considered in conformity analyses under the first proposed option unless the State or EPA determine otherwise.

The second option (in which conformity demonstrations during the pre-SIP period must consider NO

only if

the State or EPA make a finding that NO

is a significant contributor) is under consideration because the contribution of nitrates to total PM

2.5

concentrations in different metropolitan areas can vary significantly as noted above. In addition, this option would enable states to consider NO

emission reductions in combination with potential reductions of VOCs, NH

and SO

as part of the process for developing an area's attainment demonstration (due within 3 years of the area's nonattainment designation), in which air quality modeling at a more refined spatial resolution (

e.g.

12 kilometer grid size) would be performed. EPA seeks comment on the two options for addressing NO

in conformity prior to PM

2.5

SIPs.

VOC precursor emissions.

In 1999, on-road sources accounted for approximately 34% of the total VOC emissions in the 372 potential nonattainment counties for PM

2.5

(based on the 1999-2001 air quality data). Carbonaceous particles, which result, in part, from reactions involving VOCs, account for 25-70% of constructed fine particle mass measured at speciation trends network sites. The highest percentages of carbonaceous particles tend to be in California and the lowest percentages tend to be in the eastern United States.

Our understanding of the role of VOCs in PM

2.5

air quality problems continues to evolve. VOCs play several different functions in the formation of the organic fraction of PM

2.5

. The 2003 NARSTO report characterizes VOC precursors into three main categories. High molecular weight organic molecules (

i.e.

, molecules with 25 or more carbon atoms) are either emitted directly as particles or as liquids that rapidly condense onto existing particles. Intermediate weight organic molecules (e.g., compounds with 7 to 24 carbon atoms) often exhibit a range of volatilities and can exist in both the gas and aerosol phase. For this reason they are also referred to as semivolatile compounds. These compounds react at higher temperatures to form secondary organic aerosols (SOAs). Aromatic compounds such as toluene, xylene, ethyl benzene are considered to be the most significant anthropogenic SOA precursors and have been estimated to be responsible for 50 to 70 percent of SOAs. The smallest organic molecules (

i.e.

, molecules with six or less carbon atoms) occur in the atmosphere mainly as vapors and typically do not form organic particles at ambient temperatures. However, they participate in atmospheric chemistry processes resulting in the formation of ozone and certain free radical compounds (such as the hydroxyl ion [OH]). These free radicals participate in the oxidation of other gas-phase compounds (such as semivolatile aromatics) to form SOAs. The relative importance of each of these groups of organic compounds in the formation of organic particles varies from area to area. Also, the contribution of on-road source emissions to each of these three groups of organic compounds may vary from area to area.

Since on-road motor vehicles account for a substantial portion of total VOC emissions and on-road VOCs should be significant in many PM

2.5

areas, one could argue that the first proposed option is the most logical and environmental approach. Under this proposed option, VOCs would be considered in conformity automatically unless states or the EPA Regions determine that VOCs are insignificant for a given area. On the other hand, it may be appropriate to allow states and EPA the opportunity to evaluate the local significance of VOC emissions prior to consideration in conformity, given the likely variations between areas regarding the role of VOCs in the formation of PM

2.5

. EPA seeks comment on the two options for addressing VOCs in conformity prior to PM

2.5

SIPs.

precursor emissions. EPA believes that statutory requirements are met under both proposed options if SO

is only addressed in conformity if it is determined to be significant to an individual nonattainment area. Although SO

may significantly contribute to total PM

2.5

in terms of emissions from all sources, emissions inventory data indicates that on-road emissions of SO

generally represent a very small portion of the total SO

emissions. Emissions inventory data for 1999 for the 372 potential PM

2.5

nonattainment counties for PM

2.5

(based on 1999-2001 air quality data) shows that on-road sources were responsible for only 2% of total SO

emissions. By comparison, fuel combustion sources (

e.g.

, electric utility and industrial combustion of coal and oil) were responsible for approximately 88% of the SO

emissions in 1999 in these same counties.

In addition, EPA has already adopted two regulations that will greatly reduce emissions of SOx from on-road sources by the time such regulations are both in full effect in 2009. First, in 2004 the low sulfur gasoline program begins to be

phased in and is fully effective in 2007 (February 10, 2000, 65 FR 6697). This regulation will reduce the sulfur content of gasoline by approximately 90%.

Second, in 2006 the low sulfur diesel program begins to be phased in and is fully effective by 2009 (January 18, 2001, 66 FR 5001). This regulation will reduce the sulfur content of diesel fuel by approximately 97% nationally.

In addition, California has adopted its own rule which addresses the sulfur content of gasoline in that State. California's regulation is similar in stringency to the federal regulation.

Projections of on-road emissions of SO2 in 2020 in the 372 potential PM

2.5

nonattainment counties based on 1999-2001 air quality data indicates that on-road sources will be responsible for less than 1% of the total SO

emissions in 2020 in these counties.

These projections confirm that the implementation of the fuel regulations discussed above will ensure that SO

emissions from on-road sources remain at insignificant levels.

EPA 420-R-00-020, October 2002, “Procedures for Developing Base Year and Future Year Mass and Modeling Inventories for the Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel (HDD) Rulemaking.”

precursor emissions.

EPA believes that both proposed options are appropriate and consistent with the statute by only requiring NH

conformity analyses if it is found significant in a given area. States and EPA should have a better understanding of the effect of NH

reductions on PM

2.5

concentrations by 2007, when PM

2.5

SIPs would be due. Based on the limited state of knowledge about on-road mobile source NH

contributions to PM

2.5

and indications that such emissions may be small, EPA does not generally believe that any areas should be required to consider NH

in conformity before SIPs are submitted, unless the State or EPA determines that NH

emissions are significant.

First, the 2003 NARSTO-PM report states that in most areas, insufficient information exists at this time to predict how particle mass and composition would change in response to changing NH

emissions. In some areas, reductions in NH

could actually lead to formation of acid aerosols that could worsen air quality. Second, existing emissions data show that on-road sources are a relatively small contributor to national NH

emissions, approximately 5%. In addition, information on 1999 emissions indicates that about 17% of the NH

in the 372 potential PM

2.5

nonattainment counties (based on 1999-2001 air quality data) comes from on-road sources. Although this information provides some evidence that on-road NH

emissions can be important in some urban areas, this is likely due to urbanized counties having fewer agricultural and other NH

sources.

IX. Re-entrained Road Dust in PM

2.5

Regional Emissions Analyses

A. Background

Fugitive dust is released into the atmosphere by the mechanical disturbance of granular material. Common sources of fugitive dust include agricultural operations, construction, and on-road motor vehicle activity. Motor vehicles produce direct particulate emissions of dust through resuspension of loose material on the road surface, also known as re-entrained road dust.

Re-entrained road dust can come from both paved and unpaved roads, including pavement wear and decomposition, atmospheric deposition onto the road surface, mud and dirt carry-out from off-road sites, and sand, salt, and other materials applied for ice or skid control. In the preamble to the 1993 final conformity rule, EPA identified re-entrained road dust as a potential on-road mobile source contributor to some local PM

nonattainment problems. EPA stated, “All highway and transit related source categories that contribute to the nonattainment problem should be identified and included in the motor vehicle emissions budget, including exhaust, evaporative, and re-entrained dust emissions (including emissions from antiskid and deicing materials, where treated as mobile source emissions by the SIP).” (November 24, 1993, 58 FR 62194)

B. What Are We Proposing?

This part of the proposal addresses when direct PM

2.5

from re-entrained road dust would be included in conformity analyses in PM

2.5

nonattainment and maintenance areas. Once a PM

2.5

SIP is submitted, re-entrained road dust would be included in regional emissions analyses if road dust is considered significant in the context of the SIP's air quality modeling and included in an adequate or approved PM

2.5

motor vehicle emissions budget. EPA would consider the significance of road dust in its adequacy review or approval of a submitted PM

2.5

SIP. The following two options address road dust emissions in the time period before adequate or approved PM

2.5

SIP budgets are established.

The first option would require that, prior to adequate or approved PM

2.5

SIP budgets, re-entrained road dust would only be included in regional emissions analyses if the State air quality agency or EPA Regional Administrator determines that re-entrained road dust

is a significant contributor

to the PM

2.5

regional air quality problem. In other words, PM

2.5

areas could presume that re-entrained road dust is not a significant contributor and not include road dust in PM

2.5

transportation conformity analyses prior to the SIP, unless the State or EPA finds road dust significant. The proposed regulatory text for this option can be found in § 93.102(b)(3).

EPA requests comment on whether the first proposed option should be modified to require certain PM

2.5

areas that are also PM

areas to include road dust in PM

2.5

conformity analyses, if road dust is currently included in PM

conformity analyses. Such a caveat would result in a limited number of PM

2.5

areas including road dust in all PM

2.5

conformity analyses prior to a PM

2.5

SIP, unless the State or EPA found that road dust is not a significant contributor to the regional air quality problem. This proposal does not affect how re-entrained road dust is addressed in conformity for the PM

standard.

The second proposed option would require that re-entrained road dust be included in conformity analyses in all PM

2.5

nonattainment areas prior to adequate or approved PM

2.5

SIP budgets, unless the State air quality agency or EPA Regional Administrator determines that re-entrained road dust

is not a significant contributor

to the regional air quality problem. For this option, MPOs and DOT would document in their conformity determinations that regional emissions analyses for direct PM

2.5

do not include road dust emissions when EPA or the State has determined that such emissions are insignificant.

The public would be notified when road dust is considered insignificant through the documentation in a conformity determination for this option.

An EPA or State air agency finding of significant or insignificant re-entrained road dust emissions (a “significance finding”) would be based on a case-by-case review of the following factors for either proposed option: the contribution of road dust to current and future PM

2.5

nonattainment; an area's current design value for the PM

2.5

standard; whether control of road dust appears necessary to reach attainment; and whether increases in re-entrained dust emissions may interfere with attainment. Such a review would include consideration of local air quality data and/or air quality modeling results. Today's proposed options for PM

2.5

road dust are consistent with EPA's existing

insignificance policy for all areas as described in Section XIV.B.

Under either option, a significance finding should be made only after discussions with the interagency consultation group for the PM

2.5

nonattainment area. These discussions should include a review of the data being considered. Interagency consultation would also ensure that all of the relevant agencies are aware that such a finding is being considered and is supported by the air quality information that is available at the time. A significance finding would be made through a letter to the relevant state and local air quality and transportation agencies, MPO(s), DOT, and EPA (in the case of a State air agency finding).

EPA notes that any significance finding made prior to the SIP should not be viewed as the ultimate determination of the significance of road dust emissions in a given area. State and local agencies may find through the SIP development process that road dust emissions are significant and should be included in the PM

2.5

SIP motor vehicle emissions budget and subsequent conformity analyses, even in the case where road dust emissions were previously considered insignificant.

As described further below, under any of the proposed options, EPA would issue guidance on how to calculate PM

2.5

road dust emissions to reflect the true impact of re-entrained road dust on regional air quality. This guidance would be available before EPA's final PM

2.5

nonattainment designations.

See

Section IX.D. for more details on EPA's ideas for such guidance.

C. Why Are We Proposing These Options?

At issue is the question of whether or not re-entrained road dust has a significant impact on air quality and should be included in conformity analyses in all PM

2.5

areas. Existing PM

areas include re-entrained road dust in conformity because fugitive dust from roadways and other sources dominate PM

regional emissions inventories. However, the role of re-entrained road dust for PM

2.5

air quality issues is less clear. Furthermore, there does not appear to be a direct correlation between the amount of road dust calculated for PM

2.5

motor vehicle inventories and what is being collected on PM

2.5

monitoring filters, as discussed further in this section.

Specifically, analysis of local air quality data indicates wide regional variation in the fractions of PM

2.5

found on air quality monitors that consists of chemical elements associated with fugitive dust. Moreover, not all emissions of these chemical elements are attributable to re-entrained road dust, as they can also be emitted by other sources that disturb or process minerals or metals. In some areas, especially those areas in the eastern United States, preliminary analyses indicate that fugitive dust may not have a significant impact on regional air quality.

In those areas, it may be more productive prior to a PM

2.5

SIP to focus control efforts on vehicle emissions that contribute to the PM

2.5

air quality problem, rather than on re-entrained road dust emissions.

“National Air Quality and Emissions Trends Report, 1999,” EPA-454/R-01-004, U.S. EPA Office or Air Quality Planning and Standards, March 2001; also J. Szykman, D. Mintz, J. Creilson, and M. Wayland, “Impact of April 2001 Asian Dust Event on Particulate Matter Concentrations in the United States,” in the “Proceedings of the Air & Waste Management Association Symposium on Air Quality Measurement Methods and Technology, San Francisco, November 13-15, 2002.

The first proposed option would address regional variability, and ultimately allow the SIP's analysis to determine whether or not re-entrained road dust is a significant factor in the regional PM

2.5

problem. A more thorough air quality analysis as required for the SIP may be the best determination of the real impact of re-entrained road dust on PM

2.5

air quality, unless there is clear evidence before the SIP that road dust emissions are significant.

Under the first proposed option, EPA is requesting comment on whether it is appropriate to require PM

2.5

areas that are also PM

areas to include road dust in conformity analyses, unless a finding is made that road dust is not significant. Areas that are nonattainment for PM

may be more likely to have significant re-entrained road dust contributing to the PM

2.5

problem. Due to the significant amount of road dust in existing PM

inventories, it may be appropriate to also initially presume that road dust is significant for PM

2.5

for these limited number of PM

areas, unless the State or EPA find that road dust is not significant.

Finally, because the second option begins with the presumption that re-entrained road dust emissions is a problem, it may be more conservative in protecting PM

2.5

air quality with respect to the impact of road dust. However, in many areas, the second proposed option might result in the diversion of resources toward road dust analyses as well as road dust control measures that might be more effectively used to understand and control other emissions sources. These areas do have the option of supporting an EPA or state finding that road dust emissions are not significant, but this may be difficult to do prior to the completion of the SIP analysis in some areas.

D. Request for Comment on Estimating Road Dust Emissions

Under any of the proposed options, road dust SIP emissions inventories and regional emissions analyses for conformity at this time should be calculated using methods described in EPA's guidance entitled, “AP-42, Fifth Edition, Volume 1, Chapter 13, Miscellaneous Sources” (US EPA Office of Air Quality Planning and Standards; available at

http://www.epa.gov/ttn/chief/ap42/ch13/

) or locally developed estimation methods approved through the interagency consultation process. For reasons described below, under EPA's future guidance, calculated emissions would then be adjusted downward based on an analysis of the relative impact of re-entrained road dust on ambient PM

2.5

concentrations as determined by regional air quality monitors in a given area.

Review of PM

2.5

air quality data raises significant questions of uncertainty in the estimation methods for PM

2.5

dust emissions. Emissions of road dust are estimated using methods that are based on data collected from particulate monitors set up close to the road edge. These methods are used to create a PM

2.5

inventory, which is an estimation of the total amount of PM

2.5

road dust released into the atmosphere. When used with standard air quality simulation models, the methods that are used to create the inventory may adequately estimate the dust in the air immediately adjacent to the road, but may overestimate the impact that dust has on concentrations in the larger region and in particular at the PM

2.5

monitors that determine attainment with the PM

2.5

NAAQS. Regional air quality is assessed by air quality monitors that are set up in a wide range of locations. These regional air quality monitors generally indicate much lower fractions of dust in the atmosphere than are predicted based on the emissions inventories. (“Reconciling Urban Fugitive Dust Emissions Inventory and Ambient Source Contribution Estimates: Summary of Current Knowledge and needed Research”, Desert Research Institute Document 6110.4F, May 2000, available at

http://www.epa.gov/ttn/chief/efdocs/fugitivedust.pdf).

There are several likely contributing factors to explain this discrepancy. The first factor is that road dust particles are distributed more toward the high end of the PM

2.5

size range than are exhaust particle or PM

2.5

emissions from many other source types. The second factor is

the low height to which re-entrained road dust is lifted (75% of unpaved road dust emissions were less than 2 meters above the ground when they were measured; compared to emissions released from stacks at stationary sources or vertical exhaust pipes on heavy-duty trucks) (Desert Research Institute Document 6110.4F, May 2000). This low-lifting height provides an extended “opportunity” for impaction, filtration, agglomeration and other physical mechanisms that lead to particle removal to occur. The third factor is that the lack of any thermal buoyancy for dust emissions would somewhat reduce their impact, in contrast to emissions from vehicle exhaust and other combustion or high temperature sources. All three factors increase the likelihood that road dust particles would settle out of the atmosphere onto the ground or adhere onto other surfaces such as vegetation, structures,

etc.,

before contributing substantially to the PM

2.5

regional air quality problem.

There are other reasons for uncertainty associated with the current method for estimating PM

2.5

re-entrained road dust emissions. The original data used to develop this method were based on measurements of PM

rather than PM

2.5

. The PM

data were subsequently adjusted to reflect the fraction of PM

2.5

in PM

, but these adjustments add uncertainty. In addition, the data used to develop the emissions estimation method are highly variable. This variability adds to uncertainty about its interpretation. (“AP-42, Fifth Edition, Volume 1, Chapter 13: Miscellaneous Sources”, U.S. EPA Office of Air Quality Planning and Standards).

Attempting to adjust for discrepancies between estimated inventories and air quality measurements, EPA has discounted national PM

2.5

emissions inventories by 75% in air quality analyses for recent EPA rulemakings and other national analyses, to create the “effective emissions” that are used as input into regional air quality models. (Desert Research Institute Document 6110.4F, May 2000). Even with this discount, absolute air quality model predictions of the concentration of chemical elements associated with road dust typically have remained higher than observed at most urban PM

2.5

monitoring sites, suggesting that an even larger discount may be needed in at least some situations. In areas where PM

2.5

transportation conformity for road dust is required, we believe that discounting local re-entrained road dust inventories is necessary to ensure that the overall impact of road dust is properly estimated, and that decisions about control strategies for road dust emissions and exhaust emissions reflect actual relative impacts on ambient concentrations and attainment. Without these adjustments, planners may not apply the proper combination of control measures on dust and vehicle emissions needed to properly address the regional PM

2.5

air quality problem. Based on observed discrepancies, EPA believes that controls on road dust would have a much smaller impact on regional air quality than would initially appear based on unadjusted emission inventories.

Preliminary analysis of air quality data and modeling studies indicates that there will likely be wide local variation in the size of the necessary adjustments to PM

2.5

dust emissions. For this reason, it would be inappropriate to apply EPA's 75% downward adjustment for national inventories for all areas. EPA believes it is more appropriate for PM

2.5

areas to create locally-specific adjustments based on the amount of road dust on an area's monitoring filters and its relationship to an area's nonattainment problem. Therefore, EPA intends to develop methods to make these adjustments locally both before and after a regional SIP air quality analysis has been done. EPA would issue this guidance by the time PM

2.5

designations are made. EPA invites comments and suggestions for possible methods for determining such local adjustments in areas where road dust is included in conformity analyses.

X. Construction-Related Fugitive Dust in PM

2.5

Regional Emissions Analyses

A. Background

Construction-related fugitive dust is granular material released into the atmosphere during construction. Activities associated with construction-related fugitive dust emissions include land clearing, drilling and blasting, ground excavation, cut and fill operations (

i.e.

earth moving), and facility construction. Often, a large portion of such emissions results from equipment traffic over temporary roads at the construction site. Construction-related fugitive dust is distinct from re-entrained road dust, which is emitted by motor vehicles traveling over permanent paved or unpaved roads. The discussion here applies only to fugitive dust emitted during the construction of highway or transit projects.

B. What Are We Proposing?

EPA proposes to include construction-related fugitive dust from highway or transit projects in regional emissions analyses in PM

2.5

nonattainment and maintenance areas only if the SIP identifies such dust

as a significant contributor

to the regional air quality problem. In other words, PM

2.5

areas would only include construction-related fugitive dust if the SIP identifies it as contributing to an area's air quality problem. Construction-related dust emissions would not be included in any PM

2.5

conformity analyses before adequate or approved PM

2.5

SIP budgets are established. EPA has included proposed regulatory text for this option as § 93.122(e).

Under this proposal, if construction-related fugitive dust is included in transportation conformity, we propose to allow PM

2.5

SIP budgets and conformity analyses to be adjusted to reflect the true impact of construction-related fugitive dust on regional air quality, as explained in Section IX.D. EPA would issue guidance on how to calculate PM

2.5

construction dust emissions to more accurately reflect the impact of construction dust on regional air quality before EPA's final PM

2.5

nonattainment designations. Construction dust SIP emissions inventories and regional emissions analyses for conformity should be calculated using methods described in EPA's guidance entitled, “AP-42, Fifth Edition, Volume 1, Chapter 13, Miscellaneous Sources” (US EPA Office of Air Quality Planning and Standards; available at

http://www.epa.gov/ttn/chief/ap42/ch13/

) or locally developed estimation methods approved through the consultation process.

Under EPA's future guidance, calculated emissions would then be adjusted downward to account for discrepancies based on an analysis of the relative impact of construction dust on ambient PM

2.5

concentrations as determined by regional air quality monitors in a given area. See previous discussion in Section IX.D. for more details on ideas that EPA is considering for its future guidance. EPA is also requesting comment from the public on such guidance.

C. Why Are We Proposing This Option?

Section 176(c) of the Clean Air Act requires that the air quality impacts of transportation projects be evaluated so that new violations or worsened violations do not occur. If emissions of fugitive dust from highway or transit projects contribute to air quality problems in PM

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areas and as a result, air quality is worsened, then it may be appropriate to evaluate those emissions in conformity before federal funding or approval is given. Section 93.122(d) of the transportation conformity rule

requires regional PM

emissions analyses to include construction-related PM

dust if the SIP identifies such emissions as a contributor to the nonattainment problem. If construction-related fugitive PM

is not identified as a contributor to the air quality problem in the implementation plan, areas are not required to include these emissions in the regional emissions analysis for transportation conformity. The proposal applies the current rule's approach for PM

areas to PM

2.5

areas.

In nonattainment and maintenance areas where construction-related fugitive dust is a part of the nonattainment problem, we would allow states to adjust the construction-related fugitive dust SIP inventories and subsequent conformity analyses to resolve any discrepancies between the dust inventories and the amount of dust observed at air quality monitors, as described above. As noted, regional air quality monitors generally indicate much lower fractions of dust in the atmosphere than are predicted based on the emissions inventories. (Desert Research Institute Document 6110.4F, May 2000). As explained above, factors such as larger particle size, low release height, and low thermal buoyancy increase the likelihood that dust particles would quickly settle out of the atmosphere onto the ground or adhere onto other surfaces such as vegetation, structures, etc.

In areas where PM

2.5

transportation conformity for construction dust is required, we believe that discounting local construction dust inventories is necessary to ensure that the overall impact of road dust is properly estimated, and that decisions about control strategies for dust emissions (including construction dust) and exhaust emissions reflect actual relative impacts on ambient concentrations and attainment. EPA will develop separate guidance for these adjustments to SIP budgets and conformity analyses and this guidance would be available before EPA's final nonattainment designations for the PM

2.5

standard.

D. Implementation and Request for Additional Information

EPA addressed implementation issues for including construction dust in PM

conformity analyses in an October 28, 1996 memorandum.

Under the proposal, EPA would apply similar implementation guidance to PM

2.5

areas.

“Transportation Conformity: Regional Analysis of PM

Emissions from Highway and Transit Project Construction,” memorandum from Gay MacGregor, then-director, Regional and State Programs Division, Office of Mobile Sources to EPA Regional Air Division Directors.

During the development of the SIP, air quality agencies would ensure that the PM

2.5

SIP inventory clearly identifies the role (if any) of construction dust in the PM

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air quality problem. If construction dust is a contributor, dust from highway and transit projects would be included in the PM

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SIP motor vehicle emissions budget. MPOs and state transportation agencies would work together with local and state air quality agencies to ensure that construction dust emissions are properly analyzed with respect to the transportation plan and TIP for conformity analyses. If the PM

2.5

SIP identifies construction dust as a significant PM

2.5

problem, the regional emissions analysis would account for the level of construction activity, the fugitive PM

2.5

control measures in the SIP (if there are any), and the dust-producing capacity of the proposed construction activities.

XI. Compliance With PM

2.5

Control Measures

A. What Are We Proposing?

We are proposing that FHWA and FTA projects in PM

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nonattainment and maintenance areas must comply with the applicable SIP's control measures, when such measures exist. Through this proposal, FHWA/FTA would assure implementation of a required control or mitigation measure by obtaining enforceable written commitments from the project sponsor and/or operator prior to making a project-level conformity determination. This requirement would be satisfied if the project-level conformity determination contains a written commitment from the project sponsor to include the control measures in the final plans, specifications and estimates for the project. This proposal is consistent with a similar requirement for PM

areas in § 93.117 of the current conformity rule.

We should note, however, that this proposed requirement in § 93.117 is only applicable after a PM

2.5

nonattainment area has an approved PM

2.5

SIP, since the requirement is to comply with the measures in the approved SIP. Today's proposal does not affect any separate state or SIP requirements for compliance with control measures.

The purpose of a PM

2.5

control measure would be to limit the amount of PM

2.5

emissions from construction activities and/or normal use and operation associated with the project. Examples of control or mitigation measures that may be approved into a SIP include limitations on fugitive dust during construction or street sweeping. Normal project design elements (dimensions, lane widths, materials,

etc.

), however, are not considered mitigation or control measures.

EPA requests information from current PM

nonattainment and maintenance areas on how the current requirement in § 93.117 has been implemented in PM

areas and what types of measures have been effective in limiting these emissions. Information on how PM

areas have addressed this requirement and the types of measures that have been implemented could prove valuable to new PM

2.5

nonattainment areas.

B. Why Are We Proposing This Option?

The purpose of conformity is to ensure that federal actions are consistent with the SIP. If the approved SIP includes control measures for mitigating PM

2.5

emissions from federal transportation projects, then conformity should ensure that these SIP measures are implemented. We believe that this requirement would help PM

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areas achieve clean air by ensuring that federal projects comply with control measures that result in air quality improvements as anticipated in the SIP. Although such projects must comply with SIP requirements in any event, documenting compliance in a conformity determination would add an important enforcement tool to aid in SIP compliance.

The interagency consultation process is required to discuss the inclusion of control measures in an area's SIP. Section 93.105(b)(1) of the current conformity rule requires that the interagency consultation process be used in the development of the SIP, particularly when an agency is responsible “for developing, submitting or implementing provisions of an implementation plan.” The interagency consultation group may also be a source of recommendations for the most appropriate approach to addressing PM

2.5

emissions in the SIP.

Section 93.117 of the current conformity rule has an identical requirement for project-level conformity determinations in PM

nonattainment and maintenance areas. We do not believe that compliance with this requirement has been a burden for PM

areas. Therefore, we do not anticipate that our proposal in § 93.117 should be a burden on new PM

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nonattainment areas, as this requirement simply ensures that control measures which the interagency consultation group has

previously agreed upon and included in the SIP are implemented.

XII. PM

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Hot-Spot Analyses

A. What Are We Proposing?

EPA is taking comment on two options concerning the need to conduct hot-spot analyses for FHWA and FTA projects in PM

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nonattainment and maintenance areas. A hot-spot analysis as defined in § 93.101 of the rule for CO and PM

areas is an estimation of likely future localized pollutant concentrations and a comparison of those concentrations to the air quality standard. A hot-spot analysis assesses impacts on a scale smaller than the entire nonattainment or maintenance area, including for example, congested roadway intersections and highways or transit terminals, and uses a dispersion model to determine the effects of emissions on air quality. In general, a hot-spot analysis must show that the project does not cause any new violations of the air quality standard or increase the frequency or severity of existing violations. The conformity rule currently requires hot-spot analyses in CO and PM

nonattainment and maintenance areas. The reader should refer to §§ 93.116 and 93.123 of the current conformity regulation for specific CO and PM

hot-spot analysis requirements.

The first proposed option would not require hot-spot analyses for FHWA and FTA projects in PM

2.5

nonattainment and maintenance areas, for the reasons described below. We recognize that there is on-going research on PM

2.5

and, if this research provides evidence in the future that clearly indicates that transportation-related PM

2.5

hot-spots exist, we would revise the conformity rule in the future to require PM

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hot-spot analyses at locations that are most likely to experience hot-spot problems. We invite commenters with data relevant to the existence of transportation-related PM

2.5

hot-spots to submit this data during the comment period for this proposal.

EPA also requests comment on a second option that would require PM

2.5

hot-spot analyses for FHWA and FTA projects at certain types of locations if the PM

2.5

SIP for the area identifies such locations. Under this option, PM

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hot-spot analyses would not be required for any projects prior to the submission of a SIP and then only if the PM

2.5

SIP identifies susceptible types of locations.

We request comment on what potential PM

2.5

hot-spot location types could be identified in the SIP, including locations of: significant congestion, highest traffic volumes, existing or suspected future localized violations of the PM

2.5

standard, or high diesel vehicle traffic such as near freight or transit terminals. EPA seeks comment on these potential location types or others that may be appropriate to consider for the second proposed option. The locations listed above are similar to those described in §§ 93.123(a)(1)(i)-(iv) and 93.123(b)(1)(i)-(iii) of the current conformity rule where quantitative hot-spot analyses must be performed for CO and PM

. However, under this proposal, PM

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hot-spot analyses would only be required for projects at the types of locations identified in the SIP. This option would not require qualitative analyses for all projects in the PM

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nonattainment or maintenance area as is currently required for CO and PM

nonattainment and maintenance areas.

If the second option is finalized, the required hot-spot analysis would address only the contribution of directly emitted particles to ambient PM

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concentrations, including re-entrained emissions if those are addressed under conformity in that area. Typically, a hot-spot analysis would be done for an intersection, a short segment of roadway or the immediate vicinity of a transit terminal. Since secondary particles take several hours to form in the atmosphere giving emissions time to disperse beyond the immediate area of concern, hot-spot analyses could only examine direct particulate emissions that are attributable to an individual project. In other words, precursor emissions from a project would not be considered in a hot-spot analysis. Secondary particles would only be considered as part of the PM

2.5

background concentration that would be included in the assessment of whether or not a hot-spot exists.

If EPA finalizes the second option, we would provide guidance on how to identify locations where transportation-related PM

2.5

hot-spots may exist. T

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