Proposed Rule To Implement the Fine Particle National Ambient Air Quality Standards, 65984-66067 [05-20455]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 70, Number 210 (Tuesday, November 1, 2005)]
[Proposed Rules]
[Pages 65984-66067]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-20455]



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Part II





Environmental Protection Agency





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40 CFR Parts 51 and 52



Proposed Rule To Implement the Fine Particle National Ambient Air 
Quality Standards; Proposed Rule

Federal Register / Vol. 70, No. 210 / Tuesday, November 1, 2005 / 
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 51 and 52

[FRL-7969-1]
RIN 2060-AK74


Proposed Rule To Implement the Fine Particle National Ambient Air 
Quality Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rulemaking.

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SUMMARY: This proposed rule and preamble describe the requirements that 
States and Tribes must meet in their implementation plans for 
attainment of the fine particle (PM2.5) national ambient air 
quality standards (NAAQS). The health effects associated with exposure 
to PM2.5 are serious, including premature death, aggravation 
of heart and lung disease, and asthma attacks. Those particularly 
sensitive to PM2.5 exposure include older adults, people 
with heart and lung disease, and children.
    The EPA designated areas not attaining the PM2.5 
standards on December 17, 2004. The PM designations notice was 
published in the Federal Register on January 5, 2005 (70 FR 944) and 
became effective on April 5, 2005. On this same date, the Administrator 
signed a supplemental notice making certain changes to the designations 
based on 2002-2004 air quality data. The supplemental notice was 
published in the Federal Register on April 14, 2005 (70 FR 19844). A 
total of 39 areas with a population of 90 million were designated as 
nonattainment.
    Within 3 years, each State having a nonattainment area must submit 
to EPA an attainment demonstration (and associated air quality 
modeling), adopted State regulations to reduce emissions of 
PM2.5 and its precursors, and other supporting information 
demonstrating that the area will attain the standards as expeditiously 
as practicable. In order to address PM2.5 problems, EPA 
believes that States should implement a balanced program to reduce 
emissions from regional sources [such as power plants emitting sulfur 
dioxide (SO2) and nitrogen oxides (NOX)] and 
local sources (such as cars, trucks, industrial sources, and various 
other combustion or burning-related activities). States should take 
into account national, State, and local emission reduction programs 
that are already in place and projected to provide future air quality 
benefits.

DATES: The comment period on this proposal ends on January 3, 2006. 
Comments must be postmarked by the last day of the comment period and 
sent directly to the Docket Office listed in ADDRESSES (in duplicate 
form if possible).
    One public hearing will be held prior to the end of the comment 
period. The dates, times and locations will be announced separately. 
Please refer to SUPPLEMENTARY INFORMATION for additional information on 
the comment period and public hearings.

ADDRESSES: Comments may be submitted by mail to: Air Docket, 
Environmental Protection Agency, Mail code: 6102T, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460, Attention Docket ID No. OAR-2003-0062.
    Comments may also be submitted electronically, by facsimile, or 
through hand delivery/courier. Follow the detailed instructions 
provided under SUPPLEMENTARY INFORMATION.
    Documents relevant to this action are available for public 
inspection at the EPA Docket Center, located at 1301 Constitution 
Avenue, NW., Room B102, Washington, DC between 8:30 a.m. and 4:30 p.m., 
Monday through Friday, excluding legal holidays. A reasonable fee may 
be charged for copying.

FOR FURTHER INFORMATION CONTACT: Regarding PM2.5 
implementation issues, contact Mr. Richard Damberg, U.S. Environmental 
Protection Agency, Office of Air Quality Planning and Standards, Mail 
Code C504-02, Research Triangle Park, NC 27711, phone number (919) 541-
5592 or by e-mail at: damberg.rich@epa.gov. Regarding NSR issues, 
contact Mr. Raj Rao, U.S. Environmental Protection Agency, Office of 
Air Quality Planning and Standards, Mail Code C339-03, Research 
Triangle Park, NC 27711, phone number (919) 541-5344 or by e-mail at: 
rao.raj@epa.gov.

SUPPLEMENTARY INFORMATION: Section I of the preamble provides an 
overview of the PM2.5 standards, health effects associated 
with PM2.5, legal history, and EPA's overall strategy for 
reducing PM2.5 pollution. Section II provides an overview of 
the pollutants and complex atmospheric chemistry that lead to 
PM2.5 formation, the sources of emissions, and a discussion 
of policy options for addressing PM precursors in the PM2.5 
implemention program and the new source review (NSR) program.
    Section III of the preamble describes the various core elements of 
the PM2.5 implementation program, based primarily on the 
subpart 1 requirements of section 172 of the Clean Air Act (CAA). 
Important topics discussed in section III include attainment dates, 
attainment demonstrations and modeling, local emission reduction 
measures [reasonably available control technology (RACT) and reasonably 
available control measures (RACM)], and reasonable further progress 
(RFP). Section III also includes a subsection describing options for 
revising the NSR program to specifically address PM2.5. A 
number of other topics are presented for informational purposes in 
section III, including innovative program guidance, emission inventory 
requirements, addressing PM2.5 under the transportation 
conformity program, stationary source test methods for 
PM2.5, and approaches for reducing emissions through 
improved monitoring techniques.
    Section IV addresses the various statutory requirements and 
executive orders applicable to this rule. The final section contains 
proposed regulatory text for implementation of the PM2.5 
NAAQS, in the form of a proposed subpart Y amending 40 CFR part 51.

Public Hearing

    The EPA will hold one public hearing on today's proposal during the 
comment period. The details of the public hearing, including the time, 
date, and location will be provided in a future Federal Register notice 
and announced on EPA's PM2.5 implementation Web site at 
https://www.epa.gov/ttn/naaqs/pm/pm25_index.html.
    The public hearing will provide interested parties the opportunity 
to present data, views, or arguments concerning the proposed rule. The 
EPA may ask clarifying questions during the oral presentations, but 
will not respond to the presentations or comments at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as any oral comments and 
supporting information presented at a public hearing.

How Can I Get Copies of This Document and Other Related Information?

    Docket. The EPA has established an official public docket for this 
action under Docket ID No. OAR-2003-0062. 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

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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. A reasonable fee may be 
charged for copying.
    Electronic Access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at https://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 https://www.epa.gov/edocket/ to submit or view public 
comments, access the index listing of the contents of the official 
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    Certain types of information will not be placed in the EPA Dockets. 
Information claimed as CBI and other information whose disclosure is 
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feasible, publicly available docket materials will be made available in 
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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 above. The EPA intends to work towards 
providing electronic access 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 
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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 
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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.

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, OAR-2003-0062, 
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.'' The EPA is not required to consider these late comments. If 
you wish to submit CBI or information that is otherwise protected by 
statute, please follow the instructions below under, ``How Should I 
submit CBI to the Agency?'' Do not use EPA Dockets or e-mail to submit 
CBI or information protected by statute.
    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. 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. The 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. If EPA cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment.
    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 https://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-2003-0062. 
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.
    Electronic mail. Comments may be sent by e-mail to A-and-R-
Docket@epa.gov, Attention Docket ID No. OAR-2003-0062. 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 
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included as part of the comment that is placed in the official public 
docket, and made available in EPA's electronic public docket.
    Disk or CD ROM. You may submit comments on a disk or CD ROM that 
you mail to the mailing address identified under Docket above. These 
electronic submissions will be accepted in WordPerfect or ASCII file 
format. Avoid the use of special characters and any form of encryption.
    By Mail. Send your comments to Air Docket (in duplicate if 
possible), Environmental Protection Agency, Mail code: 6102T, 1200 
Pennsylvania Ave., NW., Washington, DC, 20460, Attention Docket ID No. 
OAR-2003-0062.
    By Hand Delivery or Courier. Deliver your comments to: Air Docket, 
Environmental Protection Agency, 1301 Constitution Avenue, NW., Room 
B108, Mail code: 6102T, Washington, DC 20004, Attention Docket ID No. 
OAR-2003-0062. Such deliveries are only accepted during the Docket's 
normal hours of operation as identified above under Docket.

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    By Facsimile. Fax your comments to (202) 566-1741, Attention Docket 
ID. No. OAR-2003-0062.

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: Roberto Morales, U.S. EPA, Office of Air Quality Planning and 
Standards, Mail Code C404-02, Research Triangle Park, NC 27711, 
telephone (919) 541-0880, e-mail at morales.roberto@epa.gov, Attention 
Docket ID No. OAR-2003-0062. 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 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 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.

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.

Timing

    In a number of places, this document refers to time periods (e.g., 
x number of years) after designation or after the designation date. By 
this, we mean the number of years after the effective date of 
PM2.5 designations (April 5, 2005).

Table of Contents

I. What Is the PM2.5 Problem and EPA's Strategy for 
Addressing It?
    A. What are the fine particle standards and the health effects 
they address?
    B. What is the legal history of the PM2.5 standards?
    C. What was the process for designating PM2.5 
attainment and nonattainment areas?
    D. What is the geographic extent of the PM2.5 
problem?
    E. What is EPA's overall strategy for reducing PM2.5 
pollution?
    1. The State implementation plan (SIP) system
    2. National rules
II. Fine Particles: Overview of Atmospheric Chemistry, Sources of 
Emissions, and Ambient Monitoring Data
    A. Introduction
    B. Concentration, composition and sources of fine PM
    C. The role of ammonia in sulfate, nitrate & secondary organic 
aerosol formation
    D. Regional patterns of carbon, sulfate and nitrate, and 
indications of transport
    E. Policy for addressing PM2.5 precursors
    1. Legal Authority to Regulate Precursors
    2. Proposed policy options for addressing PM2.5 
precursors in nonattainment plan programs.
III. What Are the Specific Elements of EPA's PM2.5 
Implementation Program?
    A. What classification options are under consideration for 
PM2.5 nonattainment areas?
    1. Background
    2. Proposed options for PM2.5 classifications
    a. No classification system based on design values
    b. Two-tiered classification system
    c. Rural transport classification
    B. When are PM2.5 attainment demonstrations and SIPs 
due, and what requirements must they address?
    C. What are the attainment dates for PM2.5 
nonattainment areas?
    1. Background
    2. Consideration of existing measures in proposing an attainment 
date
    3. Areas may qualify for two 1-year attainment date extensions
    4. Areas may submit a SIP demonstrating that it is impracticable 
to attain by the 5-year attainment date
    5. Areas that fail to attain or do not qualify for an attainment 
date extension
    6. Determining attainment for the PM2.5 standards
    7. How do attainment dates apply to Indian country?
    D. What are the incentives for achieving early reductions of 
PM2.5 and its precursors?
    E. How should the States and EPA balance the need to address 
long-range transport of fine particle pollution with the need for 
local emissions reductions when implementing the PM2.5 
standards?
    1. Clean Air Act provisions for achieving local and regional 
emissions reductions
    2. Regional emission reduction strategies
    3. The role of local and State emission reduction efforts in 
reducing health risks and achieving the PM2.5 standards
    4. Addressing regionally transported emissions in local area 
attainment demonstrations
    F. How will EPA address requirements for modeling and attainment 
demonstration SIPs when implementing the 24-hour and annual average 
PM2.5 standards?
    1. Introduction
    2. Areas that need to conduct modeling
    3. Modeling guidance
    4. Modeled attainment test
    5. Multi-pollutant assessments and one-atmosphere modeling
    6. Which future year(s) should be modeled?
    7. Mid-course review
    G. What requirements for RFP apply under the PM2.5 
implementation program?
    1. Background
    2. What is the baseline year from which States will track 
emission reductions for meeting RFP requirements?
    3. How does EPA propose to address the pollutants associated 
with PM2.5 in these RFP requirements?
    4. What areas must submit an RFP plan?
    a. Areas projected to attain within 5 years of designation
    b. Areas projected to attain more than 5 years from the date of 
designation must submit a 2008 RFP plan
    i. For purposes of the 2008 RFP plan, how should a nonattainment 
area define its emission reduction milestones?
    ii. For what pollutants must States reduce emissions?
    iii. How should States assess the equivalence of alternative 
combinations of pollutant emissions reductions?
    iv. How would RFP be evaluated for a sample 2008 RFP plan?
    v. What potential RFP requirements could apply for ``serious'' 
areas under the two-tiered classification option?
    5. Other RFP issues
    a. How should States account for regional control strategies in 
evaluating RFP?
    b. What geographic area should States address in RFP plans?
    c. How should RFP be addressed in multi-state nonattainment 
areas?
    d. How should States compile emission inventories for RFP plans?

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    e. What RFP requirements apply in Tribal areas?
    f. What must States submit to show whether they have met RFP 
milestones?
    H. What requirements for contingency measures should apply under 
the PM2.5 implementation program?
    I. What requirements should apply for RACM and RACT for PM2.5 
nonattainment areas?
    1. General background
    2. Background for RACT
    3. Emissions inventory analysis supporting RACT options
    4. Which PM2.5 precursors must be addressed by States 
in establishing RACT requirements?
    5. What are the proposed options for implementing the RACT 
requirement?
    6. What factors should States consider in determining whether an 
available control technology is technically feasible?
    7. What factors should States consider in determining whether an 
available control technology is economically feasible?
    8. How should condensable emissions be treated in RACT 
determinations?
    9. What are the required dates for submission and implementation 
of RACT measures?
    10. Under the PM2.5 implementation program, does a 
State need to conduct a RACT determination for an applicable source 
that already has a RACT determination in effect?
    11. What policies affect compliance with RACT for electric 
generating units?
    12. Is EPA developing PM2.5 controlled technique 
guidelines?
    13. Background for RACM
    14. What is the proposed approach for implementing RACM?
    15. What factors should States consider in determining whether 
control measures are reasonably available?
    16. What specific source categories and control measures should 
a State evaluate when determining RACM for a nonattainment area?
    17. What criteria should be met to ensure effective regulations 
or permits to implement RACT and RACM?
    J. What guidance is available to States and Tribes for 
implementing innovative programs to address the PM2.5 
problem?
    K. What aspects of transportation conformity and the 
PM2.5 standard are addressed in this proposal?
    1. What is transportation conformity?
    2. Why does transportation conformity apply to PM2.5?
    3. Why is EPA discussing transportation conformity in this 
proposal?
    4. What revisions have been made to the transportation 
conformity rule to address the PM2.5 standard?
    5. Does EPA plan to revoke the PM10 standard?
    6. Will some areas be demonstrating conformity for both 
PM10 and PM2.5 at the same time?
    7. When does transportation conformity apply to PM2.5 
nonattainment areas?
    8. How does the 1-year grace period apply in metropolitan areas?
    9. How does the 1-year grace period apply in ``donut'' areas?
    10. How does the 1-year grace period apply in isolated rural 
areas?
    L. What requirements for general conformity should apply to the 
PM2.5 standards?
    1. What is the purpose of the general conformity regulations?
    2. How is the general conformity program currently structured?
    3. Who runs the general conformity program?
    4. How does an agency demonstrate conformity?
    5. General conformity regulation revisions for the 
PM2.5 standards
    a. What de minimis emission levels will be set for pollutants 
that contribute to PM2.5 concentrations?
    b. What impact will the implementation of the PM2.5 
standards have on a State's general conformity SIP?
    c. Are there any other impacts on the SIPs related to general 
conformity based on implementation of the PM2.5 
standards?
    6. Is there a 1-year grace period which applies to general 
conformity determinations for the purposes of the PM2.5 
standards?
    M. How will the NSR program address PM2.5 and its 
precursors?
    1. Background
    2. What are the principal elements of the proposed major NSR 
program for PM2.5?
    3. Should precursors to the formation of ambient concentrations 
of PM2.5 be subject to regulation under NSR?
    a. Background
    b. Should NSR cover precursor emissions in addition to direct 
emissions of PM2.5?
    4. What is a major stationary source (major source) under the 
major NSR program for PM2.5?
    a. Background
    b. Proposed option
    c. What is the effect of this proposed option?
    5. What should the significant emissions rate be for direct 
emissions of PM2.5?
    a. Background
    b. Proposed options
    6. What should be the significant emissions rates for 
PM2.5 precursors?
    a. Background
    b. Proposed options
    7. What is the role of condensible emissions in determining 
major NSR applicability?
    8. What are the requirements of the Prevention of Significant 
Deterioration (PSD) program for attainment areas?
    9. How should BACT be implemented?
    10. What is EPA's plan for preventing significant deterioration 
of air quality for PM2.5?
    11. How will the air quality analysis required under section 
165(a)(3) be implemented?
    12. How should the PSD pre-construction monitoring requirement 
be implemented for PM2.5?
    a. Background
    b. Options for PSD preconstruction monitoring
    13. Nonattainment New Source Review (NA NSR) requirements
    14. What are the offset requirements for NA NSR?
    a. What is the required offset ratio for PM2.5 direct 
emissions?
    b. Which precursors shall be subject to the offset requirement?
    c. What is the required offset ratio for PM2.5 
precursors?
    d. Should EPA allow interprecursor trading to comply with the 
offset requirement?
    15. What are the implementation and transition issues associated 
with this rule?
    16. Implementation of PSD provisions during the SIP Development 
period
    a. Background
    b. Proposed options
    c. Rationale
    17. Implementation of the nonattainment NSR provisions during 
the SIP development period
    a. Background
    b. Implementation of NSR under the Emissions Offset 
Interpretative Ruling (40 CFR part 51, Appendix S) with revisions.
    c. Legal basis for requiring States to issue nonattainment NSR 
permits during the SIP-development period
    18. NSR applicability to precursors during the interim period
    19. Are there any Tribal concerns?
    20. What must a State or local agency do about minor sources of 
PM2.5?
    21. Supplemental program option: rural transport areas
    a. What flexible implementation options should be available for 
Transport areas?
    b. Which nonattainment areas would be eligible for the transport 
program?
    c. What would be the basic requirements of a transport 
nonattainment NSR program?
    N. How will EPA ensure that the 8-hour ozone standard will be 
implemented in a way which allows an optimal mix of controls for 
PM2.5, ozone, and regional haze?
    1. Could an area's PM2.5 strategy affect its 8-hour 
ozone and/or regional haze strategy?
    2. What guidance has EPA provided regarding ozone, 
PM2.5 and regional haze interaction?
    3. What is EPA proposing?
    O. What emission inventory requirements should apply under the 
PM2.5 NAAQS?
    P. What stationary source test methods should States use under 
the PM2.5 implementation program?
    1. Will the existing stationary source test methods for 
particulate matter (PM) be acceptable for use in PM2.5 
SIPs?
    2. Why are the existing stationary source test methods for PM 
deficient?
    3. If the stationary source test methods are changed, will the 
existing emission limitations incorporated in SIPs need to be 
changed?
    4. The existing PM test methods and the emission limits based 
upon these methods have been acceptable since 1971, why do they need 
to be changed for PM2.5?
    5. What methods are available for measuring PM size and 
condensable PM from stationary sources?
    6. Why is a new dilution-based test method being developed by 
EPA?

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    7. What types of sources should use the new dilution-based test 
method?
    8. What are the main features of the new test method?
    9. What is the schedule for finalization of the new test method?
    10. How will use of this new method affect an areas emissions 
inventory and the emissions inventory for individual sources?
    11. How will use of this new method affect a State's 
implementation program more broadly?
    Q. How can potentially inadequate source monitoring in certain 
SIP rules be improved?
    1. How does improved PM2.5 monitoring relate to title 
V monitoring?
    2. Are instrumental techniques more appropriate than visual 
emissions (VE) techniques for monitoring compliance with PM 
emissions limits, for some situations and applications?
    3. What constitutes improved monitoring?
    R. What guidance should be provided that is specific to Tribes?
    S. Are there any additional requirements related to enforcement 
and compliance?
    T. What requirements should apply to emergency episodes?
    U. What ambient monitoring requirements will apply under the 
PM2.5 NAAQS?
IV. 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 Advancement Act
    J. Executive Order 12898: Federal Actions to Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. What Is the PM2.5 Problem and EPA's Strategy for 
Addressing It?

A. What Are the Fine Particle Standards and the Health Effects They 
Address?

    Fine particles in the atmosphere are made up of a complex mixture 
of components. Common constituents include: Sulfate (SO4); 
nitrate (NO3); ammonium; elemental carbon; a great variety 
of organic compounds; and inorganic material (including metals, dust, 
sea salt, and other trace elements) generally referred to as 
``crustal'' material, although it may contain material from other 
sources. Airborne particulate matter (PM) with a nominal aerodynamic 
diameter of 2.5 micrometers or less (a micrometer is one-millionth of a 
meter, and 2.5 micrometers is less than one-seventh the average width 
of a human hair) are considered to be ``fine particles,'' and are also 
known as PM2.5. ``Primary'' particles are emitted directly 
into the air as a solid or liquid particle (e.g., elemental carbon from 
diesel engines or fire activities, or condensable organic particles 
from gasoline engines). ``Secondary'' particles (e.g., sulfate and 
nitrate) form in the atmosphere as a result of various chemical 
reactions. (See section II for a more detailed technical discussion on 
PM2.5, its precursors, formation processes, and emissions 
sources.)
    The health effects associated with exposure to PM2.5 are 
significant. Epidemiological studies have shown a significant 
correlation between elevated PM2.5 levels and premature 
mortality. Other important effects associated with PM2.5 
exposure include aggravation of respiratory and cardiovascular disease 
(as indicated by increased hospital admissions, emergency room visits, 
absences from school or work, and restricted activity days), lung 
disease, decreased lung function, asthma attacks, and certain 
cardiovascular problems. Individuals particularly sensitive to 
PM2.5 exposure include older adults, people with heart and 
lung disease, and children. On July 18, 1997, we revised the NAAQS for 
particulate matter to add new standards for fine particles, using 
PM2.5 as the indicator. We established health-based 
(primary) annual and 24-hour standards for PM2.5 (62 FR 
38652).\1\ The annual standard is a level of 15 micrograms per cubic 
meter, based on the 3-year average of annual mean PM2.5 
concentrations. The 24-hour standard is a level of 65 micrograms per 
cubic meter, based on the 3-year average of the 98th percentile of 24-
hour concentrations. The EPA established the standards based on 
significant evidence and numerous health studies demonstrating that 
serious health effects are associated with exposures to elevated levels 
of PM2.5. Estimates show that attainment of the 
PM2.5 standards would be likely to result in tens of 
thousands fewer premature deaths each year, would be likely to prevent 
tens of thousands of hospital admissions each year, and would be likely 
to prevent hundreds of thousands of doctor visits, absences from work 
and school, and respiratory illnesses in children annually. The 
research on which EPA based the 1997 standards did not identify a 
specific threshold concentration below which individuals have no PM-
related health effects, meaning that emissions reductions resulting in 
reduced concentrations below the level of the standards may continue to 
provide additional health benefits to the local population.\2\ At the 
time we established the primary standards in 1997, we also established 
welfare-based (secondary) standards identical to the primary standards. 
The secondary standards are designed to protect against major 
environmental effects of PM2.5 such as visibility 
impairment, soiling, and materials damage. The EPA also established the 
regional haze regulations in 1999 for the improvement of visual air 
quality in national parks and wilderness areas across the country. 
Because regional haze is caused primarily by light scattering and light 
absorption by fine particles in the atmosphere, EPA is encouraging the 
States to integrate their efforts to attain the PM2.5 
standards with those efforts to establish reasonable progress goals and 
associated emission reduction strategies for the purposes of improving 
air quality in our treasured natural areas under the regional haze 
program.
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    \1\ In the 1997 PM NAAQS revision, EPA also revised the standard 
for particles with a nominal aerodynamic diameter of 10 micrometers 
or less (also known as PM10). The original 
PM10 standard was established in 1987. The revised 
PM10 standard was later vacated by the court, and thus 
the 1987 PM10 standard remains in effect. Today's 
proposed implementation rule and guidance does not address 
PM10.
    \2\ Environmental Protection Agency. (1996) Air Quality Criteria 
for Particulate Matter. Research Triangle Park, NC: National Center 
for Environmental Assessment-RTP Office; report no. EPA/600/P-95/
001aF-cF. 3v.
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    The scientific assessment that resulted in the establishment of the 
PM2.5 standards included a scientific peer review and public 
comment process. We developed scientific background documents based on 
the review of hundreds of peer-reviewed scientific studies. The Clean 
Air Scientific Advisory Committee, a congressionally mandated group of 
independent scientific and technical experts, provided extensive review 
of these assessments, and found that EPA's review of the science 
provided an adequate basis for the EPA Administrator to make a 
decision. More detailed information on health effects of 
PM2.5 can be found on EPA's Web site at: https://www.epa.gov/
air/urbanair/pm/. Additional information on EPA's scientific 
assessment documents supporting the 1997 standards is available at: 
https://www.epa.gov/ttn/oarpg (see headings for ``Staff Papers'' and 
``Criteria Documents'').

[[Page 65989]]

B. What Is the Legal History of the PM2.5 Standards?

    After EPA promulgated the PM2.5 and 8-hour ozone 
standards in July 1997, several industry organizations and State 
governments challenged EPA's action in the U.S. Court of Appeals for 
the District of Columbia Circuit (the DC Circuit). This action 
initiated a long legal process, ending with a March 2002 decision by 
the DC Circuit upholding the standards and the authority on which they 
were established.
    On May 14, 1999, the three-judge panel of the DC Circuit held in a 
split decision that the CAA, as applied by EPA in setting the 1997 
standards for PM and ozone, was unconstitutional as an improper 
delegation of legislative authority to EPA. The ruling did not question 
the science or decision-making process used to establish the standards. 
The Court remanded the PM2.5 standards to EPA but did not 
vacate them. In June 1999, the Department of Justice (DOJ) and EPA 
petitioned the Court for a rehearing en banc with the entire DC Circuit 
Court. On October 29, 1999, the Court denied the petition for 
rehearing.
    The DOJ and EPA then filed a petition for certiorari with the 
United States Supreme Court in December 1999 to appeal the decision of 
the DC Circuit, and the Supreme Court issued its decision to hear the 
appeal in November 2000. The Supreme Court issued its decision on the 
merits of the appeal on February 27, 2001.\3\ In that decision, the 
Supreme Court held that EPA's approach to setting the NAAQS in 
accordance with the CAA did not constitute an unconstitutional 
delegation of authority. The Supreme Court unanimously affirmed the 
constitutionality of the CAA provision that authorizes the Agency to 
set national air quality standards, stating that this provision ``fits 
comfortably within the scope of discretion permitted by our 
precedent.'' The Supreme Court also affirmed that the CAA requires EPA 
to set standards at levels necessary to protect the public health and 
welfare, without considering the economic costs of implementing the 
standards. The Supreme Court remanded several other issues back to the 
DC Circuit, including the issue of whether EPA acted arbitrarily and 
capriciously in establishing the specific levels of the standards.
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    \3\ Whitman v. American Trucking Assoc., 121 S.Ct. 903, 911-914 
(2001) (Whitman).
---------------------------------------------------------------------------

    The DC Circuit heard arguments in this remanded case in December 
2001, and issued its decision on March 26, 2002. The DC Circuit found 
that the Agency had ``engaged in reasoned decision making,'' rejecting 
the claim that the Agency had acted arbitrarily and capriciously in 
setting the levels of the standards. This last decision by the DC 
Circuit gave EPA a clear path to move forward with implementation of 
the PM2.5 standards.
    The implementation rule we are proposing today provides specific 
requirements for State, local, and Tribal \4\ air pollution control 
agencies to address as they prepare implementation plans required by 
the CAA to attain and maintain the PM2.5 standards.\5\ Each 
State with an area that is not attaining the PM2.5 NAAQS 
will have to develop, as part of its State implementation plan (SIP), 
emission limits for appropriate sources and other requirements to 
attain the NAAQS within the timeframes set forth in the CAA.\6\ Tribes 
with jurisdiction over Indian country that is not attaining the 
PM2.5 NAAQS could voluntarily submit a Tribal implementation 
plan (TIP) but are not required to do so. However, in cases where 
Tribes elect not to submit a TIP, EPA, working with the Tribes, has the 
responsibility for developing an implementation plan in those areas.
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    \4\ The 1998 Tribal Authority Rule (TAR) (40 CFR part 49), which 
implements section 301(d) of the CAA, provides for Tribes to be 
treated in the same manner as a State in implementing sections of 
the CAA. It gives Tribes the option of developing tribal 
implementation plans (TIPs), but unlike States, Tribes are not 
required to develop implementation plans. See section III.Q. for 
further discussion of Tribal issues.
    \5\ When the term ``State'' is used hereafter, it will refer to 
States, local air agencies, and Tribal governments electing to be 
treated as States for the purposes of implementing the CAA.
    \6\ The CAA requires EPA to set ambient air quality standards 
and requires States to submit plans designed to attain those 
standards.
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C. What Was the Process for Designating PM2.5 Attainment and 
Nonattainment Areas?

    We issued guidance in April 2003 \7\ and February 2004 \8\ on the 
process for designating attainment and nonattainment areas for 
PM2.5 and on factors for States and Tribes to consider in 
defining boundaries for nonattainment areas. The guidance states that 
EPA believes the presumptive boundaries for nonattainment areas should 
be equal to the 1999 Office of Management and Budget (OMB) definitions 
of the combined metropolitan statistical area, where applicable, or the 
metropolitan statistical area. We also recognized the fact that in June 
2003, OMB released updated definitions of combined statistical areas 
and core-based statistical areas. We communicated to the States and 
Tribes that in evaluating potential nonattainment area boundaries, they 
should include any additional counties that were added in 2003 to the 
1999 metro area definitions, plus adjacent counties, in their review of 
data associated with the nine technical factors discussed in EPA 
guidance.
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    \7\ See ``Designations for the Fine Particle National Ambient 
Air Quality Standard,'' memorandum from Jeffrey R. Holmstead, 
Assistant Administrator, to EPA Regional Administrators, April 1, 
2003. Available at: https://www.epa.gov/pmdesignations/guidance.htm.
    \8\ See ``Additional Guidance on Defining Area Boundaries for 
PM2.5 Designations,'' memorandum from Lydia N. Wegman, 
Director of Air Quality Strategies and Standards Division, EPA 
Office of Air Quality Planning and Standards, to EPA Air Division 
Directors, February 12, 2004. Available at: https://www.epa.gov/
pmdesignations/guidance.htm.
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    States were required to submit their recommendations to EPA by 
February 15, 2004.\9\ Tribes were encouraged, but not required, to 
submit designation recommendations to EPA for their reservations or 
other areas under their jurisdiction. In general, the recommendations 
were based on the most recent 3 years of air quality data available 
(e.g. 2001-2003). On June 29, we sent letters to the Governors and 
Tribal leaders notifying them of any modifications we intended to make 
to their recommendations. After considering additional comments and 
information from States and Tribes, EPA issues final PM2.5 
designations on December 17, 2004. They were published in the Federal 
Register on January 5, 2005 (70 FR 944).
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    \9\ The Consolidated Appropriations Bill for FY2004 (Pub. L. 
108-199), signed by President Bush on January 23, 2004, codifies the 
required State submittal date (February 15, 2004) and the date for 
EPA to finalize PM2.5 designations (December 31, 2004) 
that were originally included in EPA's April 2003 guidance on 
PM2.5 designations.
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    The nonattainment designation for an area starts the process 
whereby a State or Tribe must develop an implementation plan that 
includes, among other things, a demonstration showing how it will 
attain the ambient standards by the attainment dates required in the 
CAA. Under section 172(b), States have up to 3 years after EPA's final 
designations to submit their SIPs to EPA. These SIPs will be due in 
April 2008, three years from the effective date of the designations.

D. What Is the Geographic Extent of the PM2.5 Problem?

    The PM2.5 ambient air quality monitoring data for the 
2001-2003 period suggest that areas violating the standards are located 
across much of the eastern half of the United States and in much of 
central and southern California.

[[Page 65990]]

A total of 47 areas comprised of 224 counties and the District of 
Columbia were designated as nonattainment in December 2004. In April 
2005, EPA issued a supplemental notice which changed the designation 
status of eight areas (with 17 counties) from nonattainment to 
attainment based on newly updated 2002-2004 air quality data. In 
addition, four areas previously designated as unclassifiable were 
changed to attainment in this notice.
    The population of the 39 PM2.5 nonattainment areas is 
significant--about 90 million, or more than 30% of the U.S. population. 
Most areas violate only the annual standard, but a few violate both the 
annual and 24-hour standards. The 2001-2003 data show that no area 
violates just the 24-hour standard.\10\
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    \10\ A listing of counties and associated PM2.5 3-
year annual average concentrations, or ``design values,'' is 
available on EPA's Web site at: https://www.epa.gov/airtrends/
values.html.
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    The distribution of the 2001-2003 design values \11\ for the 39 
nonattainment areas is shown in the table below:
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    \11\ The PM2.5 design value for a nonattainment area 
is the highest of the 3-year average concentrations calculated for 
the monitors in the area, in accordance with 40 CFR part 50, 
appendix N.

------------------------------------------------------------------------
                                                              Percent of
Design value range for PM2.5 nonattainment areas   Number of   all areas
                  (in [mu]g/m3)                      areas     (percent)
------------------------------------------------------------------------
15.1-16.0.......................................          10          26
16.1-17.0.......................................          12          31
17.1-18.0.......................................          12          31
18.1-19.0.......................................           1           3
19.1 +..........................................           4          10
                                                 -------------
    Total.......................................          39         100
------------------------------------------------------------------------

    More than 40% of the nonattainment areas, including many major 
metropolitan areas, have design values that are 2 [mu]g/m3 
or more above the annual standard.
    The EPA believes the PM2.5 problem has a substantial 
regional component because the formation and transport of secondarily 
formed particles, such as sulfates and nitrates, extends over hundreds 
of miles. The regional nature of PM2.5 is in contrast to the 
more localized nature of PM10.
    In addition, data suggests that ambient PM2.5 
concentrations tend to rise and fall in a consistent manner across very 
large geographic areas. The transport phenomena associated with 
PM2.5 and its precursors has been well-documented for many 
years. For example, one significant source of information on long-range 
transport is the National Acid Precipitation Assessment Program (NAPAP) 
research from the 1980's and its associated reports published in 
1991.\12\ Additional studies and air quality modeling analyses since 
that time have added to the body of information documenting the 
regional nature of PM2.5.\13\ Since the emissions from one 
State may contribute significantly to PM2.5 violations in 
several other States, we believe that plans to attain the 
PM2.5 standards will need to include a combination of 
national, regional, and local emission reduction strategies.
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    \12\ National Acid Precipitation Assessment Program. Acid 
Deposition: State of the Science and Technology. Washington, DC. 
1991. See also: Environmental Protection Agency. (2004) Air Quality 
Criteria for Particulate Matter. Research Triangle Park, NC: Office 
of Research and Development; report no. EPA/600/P-99/002a,bF. 
October. The 2004 PM criteria document is available at: https://
www.epa.gov/ttn/naaqs/standards/pm/s_pm_cr_cd.html.
    \13\ NARSTO (2004) Particulate Matter Assessment for Policy 
Makers: A NARSTO Assessment. P. McMurry, M. Shepherd, and J. 
Vickery, eds. Cambridge University Press, Cambridge, England. ISBN 0 
52 184287 5. For more information, see https://www.cgenv.com/NARSTO. 
See also supporting technical information for the Clear Skies Act, 
https://www.epa.gov/clearskies/, and for the Clean Air Interstate 
Rule, https://www.epa.gov/cleanairinterstaterule.
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E. What Is EPA's Overall Strategy for Reducing PM2.5 
Pollution?

    Our overall strategy for achieving the PM2.5 standards 
is based on the structure outlined in the CAA. The CAA outlines 
important roles for State and Tribal governments and for EPA in 
implementing national ambient air quality standards.
    States have primary responsibility for developing and implementing 
SIPs that contain local and in-State measures needed to achieve the air 
quality standards in each area. We assist States and Tribes by 
providing technical tools, assistance and guidance, including 
information on control measures. In addition, we set national emissions 
limits for some sources such as new motor vehicles, certain categories 
of major new sources, and existing stationary sources of toxic air 
pollutants. Where upwind sources (such as coal-fired power plants) 
contribute to downwind problems in other States or Tribes, we can also 
ensure that the upwind States address these contributing emissions, or 
we can put in place Federal regulations in situations where the upwind 
States fail to address these sources. We intend to work closely with 
States and Tribes to use an appropriate combination of national, 
regional, and local pollution reduction measures to meet the standards 
as expeditiously as practicable, as required by the CAA.
1. The State Implementation Plan (SIP) System
    A SIP is the compilation of regulations and programs that a State 
uses to carry out its responsibilities under the CAA, including the 
attainment, maintenance, and enforcement of NAAQS. (Only certain air 
quality programs and regulations implemented by States are required to 
be part of the SIP, however.) States use the SIP process to identify 
the emissions sources that contribute to the nonattainment problem in a 
particular area, and to select the emissions reduction measures most 
appropriate for that area, considering technical and economic 
feasibility, and a variety of local factors such as population 
exposure, enforceability, and economic impact. Under the CAA, SIPs must 
ensure that areas reach attainment as expeditiously as practicable. 
These plans need to take into consideration emission reductions 
resulting from national programs (such as mobile source regulations, 
the acid rain program, or maximum achievable control technology (MACT) 
standards for air toxics) as well as from State or local programs not 
directly mandated under the CAA.
    The SIP system for nonattainment areas is an important component of 
the CAA's overall strategy for meeting the PM2.5 standards, 
but it is not the only component. As noted below, the CAA also includes 
requirements for national rules or programs that will reduce emissions 
and help achieve cleaner air.
2. National Rules
    For the States to be successful in developing local plans showing 
attainment of standards, we must do our part to develop standards and 
programs to reduce emissions from sources that are more effectively and 
efficiently addressed at the national level. We also have the 
responsibility to ensure that interstate transport is addressed through 
SIPs or other means. As outlined below, we have issued final 
regulations that will achieve important emissions reductions from power 
plants, onroad and nonroad engine sources, and other sources that may 
enable some areas to meet the PM2.5 standards in the near 
term and make it easier for others to attain.
    The acid rain program, authorized under title IV of the 1990 CAA 
amendments, was projected to reduce annual SO2 emissions by 
10 million tons from 1980 levels by 2010, and to reduce annual 
NOX emissions by 2 million tons from 1980 levels by 2010. 
The EPA has implemented the acid rain

[[Page 65991]]

program in two phases: Phase I for SO2 began in 1995 and 
targeted the largest and highest-emitting coal-fired power plants. 
Phase I for NOX began in 1996. Phase II for both pollutants 
began in 2000 and sets restrictions on Phase I plants as well as many 
additional smaller coal-, gas-, and oil-fired plants. Over 2,000 
sources (mostly electricity generating facilities) are now affected by 
the Acid Rain Program. The acid rain emissions trading system had a cap 
of 8.95 million tons on the total amount of SO2 that may be 
emitted by power plants nationwide, about half the amount emitted in 
1980. Sulfate particles formed from SO2 emissions and 
nitrate particles formed from NOX emissions contribute 
significantly to total PM2.5 mass in the eastern U.S. 
(ranging from 30-50 percent), so the reductions already achieved under 
the Acid Rain Program have led to improvements in PM2.5 
concentrations across the region.
    Additional reductions in NOX emissions from power plants 
and large industrial sources were required by May 2004 under our rules 
to reduce interstate transport of ozone pollution in the eastern U.S. 
These rules are known as the NOX SIP Call, published October 
27, 1998 (63 FR 57356), and the Section 126 Rule, published May 25, 
1999 (64 FR 28250). We estimate that when fully implemented, this 
program will result in the reduction of more than one million tons of 
summertime NOX. While this program was established primarily 
to address the ground-level ozone problem in the East, it will also 
result in reduced ambient levels of nitrate, one of the main components 
of PM2.5.
    The Administration has proposed nationwide legislation--the Clear 
Skies Act \14\--to address health and environmental concerns associated 
with power plant emissions of sulfur dioxide, nitrogen oxides, and 
mercury. However, because passage of the CSA legislation is not 
assured, EPA has established the Clean Air Interstate Rule (CAIR),\15\ 
a regulatory approach to address interstate transport of pollution 
under section 110 of the CAA. Section 110 gives EPA the authority to 
require SIPs to ``prohibit * * * any source or other type of emission 
activity within the State from emitting any air pollutant in amounts 
which will contribute significantly to nonattainment in, or interfere 
with maintenance by, any other State with respect to'' any NAAQS, and 
to prohibit sources or emission activities from emitting pollutants in 
amounts which will interfere with measures required to be included in 
State plans to prevent significant deterioration of air quality or to 
protect visibility (such as the protection of 156 mandatory Federal 
class I areas under the regional haze rule \16\).
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    \14\ For more information on the proposed Clear Skies Act, see 
EPA's website: https://www.epa.gov/clearskies/.
    \15\ See https://www.epa.gov/cair.
    \16\ See 64 FR 35714, July 1, 1999.
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    CAIR, issued by EPA on March 10, 2005, employs the same emissions 
trading approach used to achieve cost-effective emission reductions 
under the acid rain program. It outlines a two-phase program with 
declining power plant emissions caps for 28 eastern states and the 
District of Columbia: SO2 caps of 3.6 million tons in 2010, 
and 2.5 million in 2015; NOX caps of 1.5 in 2009 and 1.3 in 
2015; and NOX ozone season caps of 580,000 tons in 2009 and 
480,000 tons in 2015. Emission caps are divided into State 
SO2 and NOX budgets. By the year 2015, the Clean 
Air Interstate Rule will result in:
--$85 to $100 billion in annual health benefits, annually preventing 
17,000 premature deaths, millions of lost work and school days, and 
tens of thousands of non-fatal heart attacks and hospital admissions.
--Nearly $2 billion in annual visibility benefits in southeastern 
national parks, such as Great Smoky and Shenandoah.
--Significant regional reductions in sulfur and nitrogen deposition, 
reducing the number of acidic lakes and streams in the eastern U.S.
    Current emissions standards for new cars, trucks and buses are 
reducing motor vehicle emissions of volatile organic compounds (VOCs, 
also referred to as hydrocarbons), NOX, and direct PM 
emissions (such as elemental carbon) as older vehicles are retired and 
replaced. Other existing rules are reducing emissions from several 
categories of nonroad engines. The Tier 2 motor vehicle emission 
standards, together with the associated requirements to reduce sulfur 
in gasoline, will provide additional benefits nationally beginning in 
2004.\17\ When the new tailpipe and sulfur standards are fully 
implemented, Americans will benefit from the clean-air equivalent of 
removing 164 million cars from the road.
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    \17\ See Tier II emission standards at 65 FR 6698, February 10, 
2000.
---------------------------------------------------------------------------

    These new standards require passenger vehicles to have emissions 77 
to 95 percent cleaner than those on the road today and reduce the 
sulfur content of gasoline by up to 90 percent. In addition, the 2001 
heavy-duty diesel engine regulations \18\ will lead to continued 
emissions reductions as older vehicles in that engine class are retired 
and fleets turn over. New emission standards will begin to take effect 
in model year 2007 and will apply to heavy-duty highway engines and 
vehicles. These standards are based on the use of high-efficiency 
catalytic exhaust emission control devices or comparably effective 
advanced technologies. Because these devices are damaged by sulfur, the 
level of sulfur in highway diesel fuel will be reduced by 97 percent by 
mid-2006. We project a 2.6 million ton reduction of NOX 
emissions in 2030 when the current heavy-duty vehicle fleet is 
completely replaced with newer heavy-duty vehicles that comply with 
these emission standards. By 2030, we estimate that this program will 
reduce annual emissions of hydrocarbons by 115,000 tons and PM by 
109,000 tons. These emissions reductions are on par with those that we 
anticipate from new passenger vehicles and low sulfur gasoline under 
the Tier 2 program.
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    \18\ See heavy-duty diesel engine regulations at 66 FR 5002, 
January 18, 2001.
---------------------------------------------------------------------------

    EPA also finalized national rules in May 2004 to significantly 
reduce PM2.5 and NOX emissions from nonroad 
diesel-powered equipment.\19\ These nonroad sources include 
construction, agricultural, and industrial equipment, and their 
emissions constitute an important fraction of the inventory for direct 
PM2.5 emissions (such as elemental carbon and organic 
carbon), and NOX. The EPA estimates that affected nonroad 
diesel engines currently account for about 44 percent of total diesel 
PM emissions and about 12 percent of total NOX emissions 
from mobile sources nationwide. These proportions are even higher in 
some urban areas. The diesel emission standards will reduce emissions 
from this category by more than 90 percent, and are similar to the 
onroad engine requirements implemented for highway trucks and buses. 
Because the emission control devices can be damaged by sulfur,