reservation areas of Indian country (See, Oklahoma Department of
Environmental Quality v. EPA, 740 F.3d 185 (D.C. Cir. 2014)). Under
the court's reasoning, with respect to CAA state implementation
plans, a state has primary regulatory jurisdiction in non-
reservation areas of Indian country (i.e., Indian allotments located
outside of reservations and dependent Indian communities) within its
geographic boundaries unless the EPA or a tribe has demonstrated
that a tribe has jurisdiction over a particular area of non-
reservation Indian country within the state.
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    To date, very few tribes have submitted for the EPA's approval TIPs
covering areas over which they have jurisdiction. In the absence of a
TIP, the EPA is authorized under the TAR to implement CAA programs in
such areas as necessary or appropriate. For example, an unhealthy air
quality situation on an Indian reservation may require the EPA to
develop a FIP to reduce emissions from sources on the reservation.
Likewise, if the agency determines that sources in an area under tribal
jurisdiction could interfere with a larger nonattainment area meeting
the NAAQS by its attainment date, it would develop a FIP for those
sources in consultation with the tribe, as necessary or appropriate.
    States have an obligation to notify other states in advance of any
public hearing(s) on their state plans if such plans will significantly
impact such other states. 40 CFR 51.102(d)(5). Under section 301(d) of
the CAA and the TAR, tribes may become eligible to be treated in a
manner similar to states (TAS) for this purpose. Affected tribes with
this status must also be informed of the contents of such state plans
and given access to the documentation supporting these plans. In
addition to this mandated process, the EPA encourages states to extend
the same notice to all affected tribes, regardless of their TAS status.
    Executive Orders and the EPA's Indian policies generally call for
the EPA to coordinate and consult with tribes on matters that affect
tribes. Executive Order 13175, titled, ``Consultation and Coordination
with Indian Tribal Governments'' requires the EPA to develop a process
to ensure ``meaningful and timely input by tribal officials in the
development of regulatory policies that have Tribal implications.'' In
addition, the EPA's policies include the agency's 1984 Indian Policy
relating to Indian tribes and implementation of federal environmental
programs, the April 10, 2009, Office of Air Quality Planning and
Standards guidance ``Consulting with Indian Tribal Governments,'' and
the ``EPA Policy on Consultation and Coordination With Indian Tribes.''
Consistent with these policies, the EPA intends to meet with tribes on
activities potentially affecting the attainment and maintenance of the
current and future PM2.5 NAAQS in Indian country, including
agency actions on SIPs. As such, it would be helpful for states to work
with tribes with land that is part of the same air quality area during
the SIP development process and to coordinate with tribes as they
develop their SIPs.

I. Voluntary Programs for Reducing Ambient PM2.5

1. PM Advance Program
    The EPA believes there are significant advantages for states,
tribes and local agencies to take steps to reduce direct
PM2.5 emissions and emissions of PM2.5 precursors
as early as possible. First and foremost, early reductions help to
achieve cleaner air sooner, and help to ensure continued health
protection. Second, early steps could help an area avoid a
nonattainment designation in the first place, or for an area eventually
designated as nonattainment, early reductions could help bring the area
back into attainment sooner, which may lead to qualifying for a CDD and
subsequent suspension of attainment planning requirements as described
in Section IX.C of this preamble. In addition, early action to improve
air quality can help an eventual nonattainment area, particularly an
area that has never been designated nonattainment before, to establish
working relationships between key stakeholders. The EPA's expectation
is that early actions to reduce emissions in such areas would be less
resource-intensive than actions taken once a nonattainment designation
has been made, since at that point the implementation of controls would
need to occur in conjunction with actions to comply with other
requirements such as nonattainment NSR and transportation conformity.
    In January 2013, the EPA began a new early emissions reduction
program for attainment areas called ``PM Advance,'' which is much like
the related ``Ozone Advance'' program that began in April 2012.
Additional information about the PM Advance program for the annual and
24-hour PM2.5 NAAQS is provided in a separate guidance
document that is available at http://www.epa.gov/ozonepmadvance.
2. Residential Wood Smoke Programs
    The EPA recognizes that residential wood smoke is a concern for
many nonattainment areas. The EPA estimates that wood stoves, hydronic
heaters and fireplaces emit more than 345,000 tons of PM2.5
into the air throughout the country each year--mostly during the winter
months. Residential wood smoke can increase fine particle pollution to
levels that cause significant health concerns (e.g., asthma attacks,
heart attacks, premature death). Wood smoke causes many counties
throughout the U.S. to either exceed the national health-based
standards for fine particles, or places them on the cusp of exceeding
the standards. Because wood stoves, hydronic heaters and other similar
appliances can be used around the clock in residential areas, they can
cause significant and varying health and quality of life issues.
    To reduce fine particle pollution, many PM2.5
nonattainment areas will need to address residential wood smoke. The
EPA has developed the ``Strategies for Reducing Residential Wood
Smoke''

document that provides education and outreach tools, information on
regulatory approaches to reduce wood smoke, as well as information
about voluntary programs that communities around the country have
used.\306\ In addition, it includes methods for calculating emissions
reductions, funding ideas and the basic components of a wood smoke
reduction plan that can be adopted into a SIP as an enforceable control
measure.\307\ To access the document, go to http://epa.gov/burnwise/pdfs/strategies.pdf. For more information on the EPA's wood smoke
reduction program, visit http://www.epa.gov/burnwise.
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    \306\ On February 3, 2015, the EPA strengthened the New Source
Performance Standards (NSPS) for new residential wood heaters and
established NSPS for other new wood heaters, including outdoor and
indoor wood-fired boilers (also known as hydronic heaters). The
standards will reduce emissions of direct PM2.5 as well
as carbon monoxide, VOC, air toxics (including formaldehyde, benzene
and polycyclic organic matter), and black carbon. See http://www2.epa.gov/residential-wood-heaters/new-source-performance-standards-new-residential-wood-heaters-new.
    \307\ For further guidance on incorporating voluntary measures
into a SIP, see ``Incorporating Emerging and Voluntary Measures in a
State Implementation Plan (SIP).'' U.S. EPA. Office of Air and
Radiation. September 2004. Available at http://www.epa.gov/ttn/caaa/t1/memoranda/evm_ievm_g.pdf.
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J. Improved Stationary Source Emissions Monitoring

1. Background
    For purposes of demonstrating compliance with the EPA's air quality
regulatory requirements, the EPA, air agencies, and sources rely on two
basic types of monitoring: ambient air quality monitoring and
stationary source emissions monitoring. Ambient air quality monitoring,
as discussed in Section II of this preamble, entails collecting and
measuring samples of criteria pollutants in ambient air to evaluate air
quality as compared to clean air standards and historical information.
Stationary source emissions monitoring, on the other hand, entails
collecting and using measurement data (or other information) from
individual stationary sources to demonstrate compliance with emissions
standards, to assess process or control device performance, or to
verify work practices. While ambient air quality monitoring is used to
assess compliance with the NAAQS, stationary source emissions
monitoring is used to assess compliance with source-specific
regulations under programs like the New Source Performance Standards
(NSPS), the National Emissions Standards for Hazardous Air Pollutants
(NESHAP), the compliance assurance monitoring (CAM) program, the title
V air operating permits program, and the acid deposition control
program, as well as specific SIP control measures.\308\
---------------------------------------------------------------------------

    \308\ Regulations governing the implementation of these programs
are located at 40 CFR parts 60, 61, 63, 64, 70, 71 and 75.
---------------------------------------------------------------------------

    Accurate stationary source emissions monitoring is critical for
purposes of developing accurate emissions inventories and in order to
identify appropriate control measures to reduce emissions from
stationary sources. In addition, after control measures are in place,
stationary source emissions monitoring provides process and control
device performance information to the facility operator so that
appropriate corrective action can be taken if emission levels exceed
applicable thresholds. Thus, appropriate stationary source emissions
monitoring requirements, like the control measures with which they are
associated, are a fundamental element of an approvable attainment plan.
    By way of example, in a limited study on improving stationary
source emissions monitoring, the EPA found that revising the
measurement technique at a stationary source could provide information
to the facility operator to take corrective action that could
potentially reduce emissions up to 15 percent, and that increasing
monitoring frequency at the facility could provide information that
could be used to inform corrective actions that could yield potential
stationary source emissions reductions of up to 13
percent.309 310 Implementation of stationary source
emissions monitoring improvements could thus lead to actions to achieve
additional emissions reductions not only at individual sources but also
in the nonattainment areas where these sources are located.
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    \309\ Impact of Improved Monitoring on PM2.5
Emissions, memorandum from L. Barr and K. Schaffner, RTI
International, to B. Parker, U.S. Environmental Protection Agency.
December 2003.
    \310\ As discussed in Section IX.E of this preamble, emissions
monitoring has four essential components: (i) indicator(s) of
performance; (ii) measurement technique(s); (iii) monitoring
frequency; and, (iv) averaging time.
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2. Guidance To Help Improve Stationary Source Emissions Monitoring
    Because of the important role that effective stationary source
emissions monitoring can play in informing the development of
attainment strategies for PM2.5 NAAQS nonattainment areas,
the EPA is interested in applied best practices for stationary source
emissions monitoring that could be included in guidance for other
stationary sources and air agencies. The EPA seeks to gather
information about ways to make the source emissions monitoring data
collection process easier and more transparent. The EPA therefore seeks
appropriate examples and supporting data from individual sources and
air agencies with experience in this area to inform such future
guidance. The EPA also seeks comment on the specific topics and
questions that follow, which the agency may address in future guidance
related to improved source monitoring. Specifically:
    (1) Based on your experience, in which cases do you believe
improved monitoring techniques are more appropriate than visual
emissions (VE) techniques for monitoring compliance with
PM2.5 (or PM, in general) emissions limits? Please identify
monitoring techniques that you would recommend in lieu of VE, and
describe the instances in which VE remains appropriate.
    (2) Based on your experience, are bag leak detection systems, PM
continuous parameter monitoring systems (CPMS), or PM continuous
emissions monitoring systems (CEMS) reliable, cost-effective methods
for monitoring compliance with PM emissions? Please provide additional
information on reliability and cost to support your position.
    (3) Will increasing the frequency of VE observations resolve the
issue of applicability of VE techniques for monitoring compliance with
PM2.5 emissions? In other words, are there situations in
which increased VE frequency (i.e., daily versus weekly) would be
expected to have no impact on compliance with PM2.5 emission
limits? If so, please provide relevant data and explanation of such
situations.
    (4) Should the EPA consider mandating through rulemaking the use of
alternatives to VE techniques for monitoring compliance with
PM2.5 and PM emissions limits in certain situations and
applications? If so, in what cases?
    (5) Should the EPA's effort with regard to the use of improved
monitoring techniques in lieu of VE monitoring be focused on applicable
requirements established/relied upon for compliance with the
PM2.5 NAAQS, or should the agency more broadly address other
applicable requirements where VE techniques are commonly used (e.g., to
estimate TSP and PM10 emissions)?
    (6) Should the EPA consider mandating through rulemaking the use of
alternatives to continuous opacity monitoring systems (COMS) for
monitoring compliance with PM2.5 and PM emissions limits in
certain situations and applications? If so, in what cases?

    (7) In its study published in 2003, the EPA identified stationary
source emission reduction techniques that air agencies should consider
when developing their potential list of control measures for a
PM2.5 NAAQS nonattainment area.\311\ Specifically, the EPA
identified improved measurement techniques and increased monitoring
frequency as practices that could better inform sources and air
agencies of excess emissions from individual sources which, if
responded to more quickly, could yield significant reductions and
assist in bringing the area into attainment for the NAAQS. Please
comment on whether these techniques remain appropriate, given that they
were based on the best technical information available at the time. Are
there ways to improve the methodologies described in the study?
---------------------------------------------------------------------------

    \311\ Ibid.
---------------------------------------------------------------------------

    (8) Please submit any examples of improved stationary source
emissions monitoring, including a description of the measure,
monitoring data, etc.
    (9) Please submit any other methodologies--complete with equations
and explanations--for estimating emissions reductions due to improved
monitoring.
    The EPA will continue to explore and implement innovative, cost-
effective ideas that offer tangible incentives for improved source
monitoring to be adopted as part of the associated emissions
limitations that will help achieve additional reductions from
stationary sources and bring areas into attainment for the
PM2.5 NAAQS in a timely way.

K. Stationary Source Test Methods for Emissions of Condensable PM2.5

1. Background
    As discussed in Section II of this preamble, direct
PM2.5 comprises of two components: Filterable
PM2.5 and condensable PM2.5 emissions. Accurate
test methods for quantifying filterable PM emissions have been
available for air agencies and states to apply since the early 1970s.
In addition, controls have improved over the past 40 years and most
sources now achieve substantially lower emissions than required by
state and federal emissions limits. With the filterable portion of
PM2.5 emissions being relatively well controlled, the
condensable portion of PM2.5 emissions now represents a
larger share of overall PM2.5 emissions for several
categories of stationary sources. However, accurate test methods for
condensable PM2.5 emissions have only been recently
developed and approved by the EPA. Thus, many states may have
stationary source emission limits adopted into their existing SIPs
based only on filterable PM2.5 emissions or based on
outdated methods for measuring or estimating condensable
PM2.5 emissions.
    The following discussion focuses on current test methods for
quantifying condensable PM2.5 emissions and the EPA's
proposed requirements for states developing control strategies for
PM2.5 nonattainment areas.
2. Test Methods for Condensable PM From Stationary Sources
    Since January 1, 2011, the EPA has required that states take into
consideration condensable PM2.5 emissions when establishing
emission limits for stationary sources as part of any control strategy
for PM2.5 NAAQS nonattainment areas.\312\ This date
coincided with the effective date of the agency's revisions to test
methods for measuring filterable PM10 emissions from
stationary sources (Method 201A) and for measuring condensable PM
emissions from stationary sources (Method 202).\313\ The revisions
increased the precision of Method 202 and improved the consistency in
the measurements obtained between source tests performed under
different regulatory authorities.
---------------------------------------------------------------------------

    \312\ 72 FR 20586 (April 25, 2007).
    \313\ 75 FR 80118 (December 21, 2010).
---------------------------------------------------------------------------

    In the preamble to the 2007 PM2.5 Implementation Rule,
the EPA explained that the use of the (then anticipated) revisions to
the EPA Method 201A combined with Method 202 to obtain measured source
specific emissions of PM2.5 would improve the quality of
emissions inventories for stationary sources and would aid in the
development of a more reliable attainment strategy, as sources that may
have a considerable amount of condensable PM2.5 emissions
could be better characterized with the new methods. The EPA continues
to believe that using these improved test methods can help identify
sources of direct PM2.5 emissions which, if better
controlled, can help to bring a PM2.5 nonattainment area
into attainment. Likewise, use of these test methods may help a state
identify sources whose condensable emissions may have been incorrectly
estimated and therefore may not provide meaningful PM2.5
control opportunities.
3. Proposed SIP Requirements for Test Methods For Condensable
PM2.5 Emissions
    The EPA proposes to require that, where a state needs to adopt
control measures for direct PM2.5 from sources in a
nonattainment area, the state must specify PM2.5 emission
limits in its SIP that include both filterable and condensable
emissions. In addition, compliance testing of those sources must
include measurement of condensable emissions (such as through the use
of Method 202). Under this proposal, any new or revised emission limit
used as a control measure to bring an area into attainment for any
current or future PM2.5 NAAQS must use methods that measure
PM2.5 or total PM including both filterable and condensable
particulate matter. Existing emission limitations that are not being
revised as part of a Moderate area or Serious area attainment plan can
remain as filterable PM or whatever test method is used by the state
for compliance determination. In these cases, the acceptability of
existing stationary source test methods for PM2.5 attainment
plans will depend upon what is required under the state's current test
methods for PM emissions. The EPA believes that this proposed
requirement is appropriate because the addition of the condensable
portion of PM2.5 to filterable PM2.5 may increase
direct PM2.5 emissions by a factor of five or more, and the
use of test methods that only measure filterable emissions potentially
limit the control measures available for developing cost effective
strategies to achieve attainment of the PM2.5 NAAQS.
    The EPA seeks comment on this proposed requirement for states to
quantify condensable PM2.5 emissions in their attainment
plans for PM2.5 nonattainment areas.

X. What is the EPA proposing with respect to revoking the 1997 primary
annual PM2.5 NAAQS?

A. Background

    If the 1997 primary annual PM2.5 NAAQS were to remain in
place after conformity requirements begin to apply for the 2012 primary
annual PM2.5 NAAQS (1 year after the effective date of
designations), a number of federal agencies, metropolitan planning
organizations (MPOs) and other state, local, and federal transportation
and air quality agencies in areas that are currently designated
nonattainment or maintenance for the 1997 annual PM2.5 NAAQS
and will be designated nonattainment for the 2012 primary annual NAAQS
would be required to implement conformity requirements for both annual
PM2.5 NAAQS concurrently. Additionally, some areas would
also be implementing conformity requirements for the 2006 24-hour
PM2.5

NAAQS, and two areas remain subject to conformity requirements for the
1997 24-hour PM2.5 NAAQS. This could lead to unnecessary
complexity for transportation conformity determinations, especially if
an area's boundaries for the various PM2.5 NAAQS differ from
one another and the same test of conformity cannot be used for all of
the PM2.5 NAAQS. Even where an area's boundaries are
unchanged, different analysis years under the conformity rules may be
required for each PM2.5 NAAQS. It could also lead to general
conformity determinations being made in areas that are attainment for
the 2012 primary annual PM2.5 NAAQS. Finally, state and
local air quality agencies would be required to continue attainment
planning activities for the 1997 primary annual PM2.5 NAAQS
even if they had air quality data that resulted in their being
designated attainment for the 2012 primary annual PM2.5
NAAQS.
    The EPA believes that it is more important and consistent with CAA
requirements to determine conformity for the new 2012 primary annual
PM2.5 NAAQS, which is more stringent and thus more
protective of health than the 1997 PM2.5 NAAQS. This section
therefore describes the EPA's proposed approaches for transitioning
from the 1997 primary annual PM2.5 NAAQS to the 2012 primary
annual PM2.5 NAAQS. This section discusses a number of
options for revoking the 1997 primary annual PM2.5 NAAQS and
addresses anti-backsliding requirements that would apply, as
appropriate, under each of the revocation options. The EPA is not
proposing to revoke the 1997 secondary annual PM2.5 NAAQS in
this action because that NAAQS has been retained in order to prevent
certain welfare effects associated with PM2.5.\314\
---------------------------------------------------------------------------

    \314\ 78 FR 3086 (January 15, 2013).
---------------------------------------------------------------------------

    The proposed options are framed in the context of the CAA
requirements that apply to NAAQS transitions to ensure that states and
nonattainment areas continue to make progress and do not reverse
progress, or backslide, from improvements already made in air quality.
The CAA contains several provisions indicating congressional intent not
to allow a state to alter or remove provisions from an approved
attainment plan if the revision would reduce air quality protection.
Section 193 of the CAA prohibits modification of a control requirement
in effect or required to be adopted as of November 15, 1990 (the date
of enactment of the 1990 CAA Amendments), unless such a modification
would ensure equivalent or greater emissions reductions. Section
172(e), which addresses relaxations of a NAAQS, requires protections
for areas that have not attained a NAAQS prior to a relaxation by
requiring controls which are at least as stringent as the controls
applicable in nonattainment areas prior to any such relaxation. Section
110(l) provides that a SIP revision cannot be approved if it will
interfere with attainment or other CAA requirements. Under section
175A(d), an area that is redesignated to attainment may, with an
appropriate showing of no interference, cease to implement a measure
that is contained in the SIP at the time of redesignation, but only if
that measure is retained as a contingency measure in the area's
maintenance plan.315 316
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    \315\ Nonattainment areas that were redesignated to attainment
with an approved section 175A maintenance plan are referred to
throughout this document as ``maintenance areas.''
    \316\ Unimplemented requirements in the SIP or those shown to be
unnecessary for maintenance can be shifted to the contingency
measures portion of the SIP upon redesignation. See ``Procedures for
Processing Requests to Redesignate Areas to Attainment,'' Memorandum
from John Calcagni, Director, Air Quality Management Division,
September 4, 1992; ``State Implementation Plan (SIP) Requirements
for Areas Submitting Requests for Redesignation to Attainment of the
Ozone and Carbon Monoxide (CO) National Ambient Air Quality
Standards (NAAQS) On or After November 15, 1992,'' Memorandum from
Michael H. Shapiro, Acting Assistant Administrator for Air and
Radiation, September 17, 1993. As discussed elsewhere in this
document, an exception is made for NNSR, which can be removed from
the SIP completely and need not be retained as a contingency measure
after redesignation to attainment.
---------------------------------------------------------------------------

    The transition from the 1997 to the 2012 primary annual
PM2.5 NAAQS is a straightforward tightening of the level
with little change in the form of the standard, so it is unambiguous
that the 2012 primary annual PM2.5 NAAQS is more stringent
than the 1997 primary annual PM2.5 NAAQS. In the final 2012
PM NAAQS rule the EPA eliminated the provisions that allowed for an
area to use spatial averaging of monitoring data to determine whether
or not it is attaining the 1997, 2012 and any future annual
PM2.5 NAAQS.\317\ Eliminating spatial averaging provides
additional protection for populations that may be at a greater risk to
exposures of elevated levels of PM2.5. In these
circumstances where the annual PM2.5 NAAQS has clearly been
strengthened, section 172(e) on its face does not apply. The EPA's
interpretation that anti-backsliding provisions consistent with the
purposes of section 172(e) by analogy should apply as upheld by the
court in South Coast as appropriate in the absence of statutory
provisions addressing tightened air quality standards. In proposing
anti-backsliding requirements that would apply as appropriate to the
options that are being considered, the EPA seeks to apply the
principles of section 172(e).\318\
---------------------------------------------------------------------------

    \317\ See the Federal Register published on January 15, 2013 (78
FR 3085, 3124, 3125, 3126, 3137 and 3229).
    \318\ South Coast Air Quality Management District v. EPA, 472
F.3d 882 (D.C. Cir. 2006).
---------------------------------------------------------------------------

B. History of Revocation of Other NAAQS

    The EPA has either adopted or has proposed to adopt transition
policies for other NAAQS, including the policies for the transitions
from:
     The 1-hour ozone NAAQS to the 1997 ozone NAAQS;
     The 1997 ozone NAAQS to the 2008 ozone NAAQS;
     The prior lead NAAQS to the 2008 lead NAAQS; and,
     The prior sulfur dioxide (SO2) NAAQS to the
2010 SO2 NAAQS.
    It is important to note that for all previous NAAQS transitions,
the EPA has used revocation to reduce the burden associated with
implementing a NAAQS that has been replaced with a more stringent
NAAQS.
    In its Phase 1 Rule for the transition from the 1-hour ozone NAAQS
to the 1997 ozone NAAQS, the EPA stated that the 1-hour ozone NAAQS
would be revoked (i.e., no longer apply) 1 year after the effective
date of initial area designations for the 1997 ozone NAAQS. The EPA
also included anti-backsliding requirements in the Phase 1 Rule to
address the transition between the two standards.
    The Phase 1 Rule for implementation of the 1997 ozone NAAQS was the
subject of legal challenges, and the resulting court decision in South
Coast upheld the EPA's authority to revoke the 1-hour ozone NAAQS as
long as adequate anti-backsliding measures were retained to prevent
backsliding.\319\ The decision directed the EPA to provide additional
1-hour ozone NAAQS anti-backsliding requirements for NNSR, section 185
fees, and section 172(c)(9) and 182(c)(9) contingency measures for
failure to attain the 1-hour ozone NAAQS by the applicable attainment
date or to make reasonable further progress toward attainment of that
standard, in addition to the anti-backsliding measures contained in the
Phase 1 rule.\320\
---------------------------------------------------------------------------

    \319\ South Coast Air Quality Management District v. EPA, 472
F.3d 882 (D.C. Cir. 2006).
    \320\ For a more complete discussion of the requirements for the
transition from the 1-hour ozone NAAQS to the 1997 ozone NAAQS, see
the Federal Register dated April 30, 2004 (69 FR 23951, 23969,
23970, 23971, 23972, 23973, 23974, 23975, 23976, 23977, 23978,
23979, 23980, 23981, 23982, 23983, 23984, 23985, 23986, 23987, 23988
and 23989).

---------------------------------------------------------------------------

    As part of its final SIP requirements rule for the 2008 ozone
NAAQS, the EPA included requirements for the transition from the 1997
ozone NAAQS to the 2008 ozone NAAQS.\321\ In developing that
rulemaking, the EPA built upon its experience in implementing the Phase
1 rule for the transition from the 1-hour ozone NAAQS to the 1997 ozone
NAAQS and the decision in the South Coast litigation. The EPA revoked
the 1997 ozone NAAQS on the effective date of the final SIP
requirements rule and finalized anti-backsliding requirements
consistent with the implementation of the court decision for the
previous ozone transition that would apply in areas designated
nonattainment for the 1997 ozone NAAQS at the time of revocation.\322\
---------------------------------------------------------------------------

    \321\ See the published proposal at 78 FR 34178 (June 6, 2013)
and the final SIP requirements rule for the 2008 ozone NAAQS at
http://www.epa.gov/groundlevelozone/implement.html.
    \322\ Ibid.
---------------------------------------------------------------------------

    It should be noted that as part of the transition from the 1997
ozone NAAQS to the 2008 ozone NAAQS, the EPA revoked the 1997 ozone
NAAQS for transportation conformity purposes only in a separate action
related to classifications for the 2008 ozone NAAQS that was finalized
prior to the time that the full implementation rule had been
proposed.\323\ The EPA took this action because the D.C. Circuit Court
in litigation on the transportation conformity rule and in its decision
in the South Coast litigation affirmed that the use of motor vehicle
emissions budgets that have been approved or found adequate for use in
transportation conformity determinations for the prior NAAQS must be
used in transportation conformity determinations for the new NAAQS
until a state submits motor vehicle emissions budgets for the new NAAQS
and those budgets are either found adequate or are
approved.324 325 These cases seemed to indicate that the use
of these existing budgets until new budgets are available is the
appropriate anti-backsliding measure with respect to transportation
conformity to support revocation for that purpose.\326\ It should be
noted, however, that the revocation of the 1997 ozone NAAQS for
transportation conformity purposes was the subject of litigation in the
D.C. Circuit Court.\327\ The court issued its decision on December 23,
2014, and held that the EPA lacked authority to revoke the 1997 ozone
NAAQS only for transportation conformity purposes because for areas
that remain designated as nonattainment or maintenance for the 1997
ozone NAAQS, CAA section 176(c) requires transportation conformity
determinations in nonattainment and maintenance areas.
---------------------------------------------------------------------------

    \323\ 77 FR 30160 (May 21, 2012).
    \324\ See South Coast Air Quality Management District v. EPA,
472 F.3d 882 (D.C. Cir. 2006).
    \325\ 40 CFR 93.101 defines ``motor vehicle emissions budget''
as ``that portion of the total allowable emissions defined in the
submitted or approved control strategy implementation plan revision
or maintenance plan for a certain date for the purpose of meeting
reasonable further progress milestones or demonstrating attainment
or maintenance of the NAAQS, for any criteria pollutant or its
precursors, allocated to highway and transit vehicle use and
emissions.''
    \326\ In addition, the Court affirmed that conformity
determinations need not be made for a revoked standard.
    \327\ NRDC v. EPA, No. 12-1321 (D.C. Cir.) (challenging EPA
actions taken at 77 FR 30160 (May 21, 2012)).
---------------------------------------------------------------------------

    Following promulgation of the 2008 lead NAAQS and 2010
SO2 NAAQS, the EPA revoked the prior lead and SO2
NAAQS for all purposes in areas that had attained the prior NAAQS and
had been redesignated to attainment, as well as in areas that had
initially been designated as attainment for those NAAQS. The EPA
retained the prior NAAQS in areas that had not yet attained those NAAQS
until those areas had an approved attainment plan for the revised
NAAQS. Because the EPA revoked the prior lead and SO2 NAAQS
in areas that had been redesignated to attainment for those NAAQS, the
EPA primarily relied on the CAA's anti-backsliding provisions found in
sections 110(l) and 193 in order to provide anti-backsliding
protection.\328\
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    \328\ For details on the requirements for the lead NAAQS and the
SO2 NAAQS, respectively, see 73 FR 66964 (November 12,
2008), at page 67043; and 75 FR 35519 (June 22, 2010), at page
35580.
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    In developing the options for revoking the 1997 primary annual
PM2.5 NAAQS contained in this proposal, the EPA has drawn
from these prior anti-backsliding approaches.

C. Proposed Options for Revocation and Related Anti-Backsliding
Requirements for the 1997 Primary Annual PM2.5 NAAQS

    The EPA is proposing and seeking comment on two options for
revoking the 1997 primary annual PM2.5 NAAQS and is seeking
comment on whether to revoke the NAAQS at the current time. Under
either of the options to revoke the 1997 NAAQS, revocation would take
effect no sooner than 1 year after the effective date of designations
for the 2012 primary annual PM2.5 NAAQS. One of these
options would provide for revocation at a later date for some areas.
    After revocation of the 1997 primary annual PM2.5 NAAQS,
the designations (and the classifications associated with those
designations) for that standard would no longer be in effect, and the
designations that would remain in effect would be those for the 1997
secondary annual PM2.5 NAAQS, the 2006 primary and secondary
24-hour PM2.5 NAAQS and the 2012 primary annual
PM2.5 NAAQS. However, the EPA would retain the listing of
the designated nonattainment areas for the revoked 1997 primary annual
PM2.5 NAAQS in 40 CFR part 81, for the sole purpose of
identifying the anti-backsliding requirements that may apply to the
areas at the time of revocation. Accordingly, such references to
historical designations for the revoked standard should not be viewed
as current designations under CAA section 107(d).
    For any proposed option that allows for revocation in nonattainment
areas for the 1997 primary annual PM2.5 NAAQS, the EPA is
also proposing anti-backsliding provisions to ensure that in these
areas: (i) There is protection against degradation of air quality
(e.g., the areas do not backslide in terms of air quality
improvements); (ii) the areas continue to make progress toward
attainment of the new, more stringent 2012 primary annual
PM2.5 NAAQS; and, (iii) there is consistency with the
PM2.5 NAAQS implementation framework outlined in subpart 4
of part D, title I of the CAA. At the current time, there are 14 areas
that continue to be designated as nonattainment for the 1997 annual
PM2.5 NAAQS; however all but 2 of these areas have 2011-2013
air quality data showing that they are attaining that NAAQS. Therefore,
the EPA expects many of these current nonattainment areas will be
eligible to seek redesignation to attainment prior to any revocation.
The EPA is proposing and seeking comment on the following two options:
     Option 1: Revoke the 1997 primary annual PM2.5
NAAQS for all purposes in attainment areas for that NAAQS 1 year after
the effective date of the designations for the 2012 primary annual
PM2.5 NAAQS; or,
     Option 2: Revoke the 1997 primary annual PM2.5
NAAQS for all purposes in all nonattainment and attainment areas for
that NAAQS 1 year after the effective date of the designations for the
2012 primary annual PM2.5 NAAQS.
    More details on the proposed options and associated rationale are
included below.

1. Option 1: Revoke the 1997 Primary Annual PM2.5 NAAQS for
All Purposes in Attainment Areas for That NAAQS 1 Year After the
Effective Date of the Designations for the 2012 Primary Annual
PM2.5 NAAQS
    The EPA's first proposed option would revoke the 1997 primary
annual PM2.5 NAAQS for all purposes in areas that are
designated as attainment for that NAAQS 1 year after the effective date
of designations for the 2012 primary annual PM2.5 NAAQS, as
well as in future areas that are redesignated as attainment areas after
the initial revocation. The areas addressed by this option are those
that were originally designated as attainment areas for the 1997
primary PM2.5 NAAQS and those that were originally
designated as nonattainment but have since or will in the future be
redesignated to attainment for that NAAQS. Under this option, the EPA
would not revoke the 1997 primary annual PM2.5 NAAQS in any
area that is designated nonattainment for that NAAQS.
    Areas that are designated nonattainment for the 1997 annual
PM2.5 NAAQS at the time of the initial revocation would be
required to continue to meet all applicable requirements for such
NAAQS, and could continue to seek redesignation to attainment for the
1997 primary annual PM2.5 NAAQS. For example, even if the
revocation were to become effective in April 2016, redesignations could
continue to be approved after that date. For such areas, the effective
date of the revocation would be the effective date of the area's
redesignation to attainment for the 1997 annual PM2.5 NAAQS.
    The EPA notes that under proposed Option 1 it is unnecessary to
propose anti-backsliding requirements for the 1997 primary annual
PM2.5 NAAQS, since Option 1 would only revoke this NAAQS in
attainment areas. Anti-backsliding requirements are not applicable to
attainment areas (i.e., for former nonattainment areas that have been
redesignated to attainment the EPA has already determined through the
redesignation process and approval of maintenance plans that all
applicable requirements for the 1997 primary annual PM2.5
NAAQS--including anti-backsliding requirements--have been fulfilled and
areas that have always been designated attainment for this NAAQS).
    For areas that were initially designated as attainment for both the
1997 and 2012 annual PM2.5 NAAQS the EPA is proposing that
the approved PSD SIPs for these areas satisfy the obligation to submit
an approvable maintenance plan for the 2012 primary annual
PM2.5 NAAQS under section 110(a)(1).
    The EPA also notes that areas designated nonattainment for the 2012
primary annual PM2.5 NAAQS would be required to comply with
applicable conformity requirements beginning 1 year after the effective
date of designations for that NAAQS. For transportation conformity
purposes these requirements would include using adequate or approved
motor vehicle emissions budgets for the 1997 annual PM2.5
NAAQS where they exist until the area has approved or adequate budgets
for the 2012 primary annual PM2.5 NAAQS.\329\ The use of
such budgets serves as the appropriate anti-backsliding measure for
transportation conformity purposes.
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    \329\ Areas that do not have adequate or approved motor vehicle
emissions budgets for the 1997 annual PM2.5 NAAQS or the
2006 24-hour PM2.5 NAAQS would use one of the two interim
emissions tests required by 40 CFR 93.109(c)(3) and 40 CFR
93.119(b).
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    In general, Option 1 builds upon the EPA's practice in the
transition from the 1-hour to the 1997 ozone NAAQS in that areas will
not only be able to be redesignated to attainment up to the date of the
initial revocation, but any remaining nonattainment areas will be able
to be redesignated after the initial revocations occur 1 year after the
effective date of designations.\330\ This approach is also consistent
with the approach established for the transition from the prior lead
and SO2 NAAQS to the current lead and SO2 NAAQS.
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    \330\ Although section 51.905(a) specified that the anti-
backsliding requirements ``attached'' at the time of designation for
the 1997 ozone NAAQS, areas were still able to redesignate to
attainment for the 1-hour ozone NAAQS up to the date of revocation
of that standard.
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2. Option 2: Revoke the 1997 Primary Annual PM2.5 NAAQS for
All Purposes in All Nonattainment and Attainment Areas for That NAAQS 1
Year After the Effective Date of Designations for the 2012 Primary
Annual PM2.5 NAAQS
    Under this second proposed option, the EPA would revoke the 1997
primary annual PM2.5 NAAQS for all purposes in all
nonattainment and attainment areas 1 year after the effective date of
designations for the 2012 primary annual PM2.5 NAAQS. The
requirements for revoking the 1997 primary annual NAAQS in attainment
areas for that NAAQS are discussed under proposed Option 1. However,
revoking the 1997 primary annual PM2.5 NAAQS in
nonattainment areas for that NAAQS would require anti-backsliding
measures. Therefore, the EPA is proposing the following anti-
backsliding measures for any designated nonattainment areas that exist
for the 1997 primary annual PM2.5 NAAQS upon the effective
date of the proposed revocation:
     For areas designated attainment for the 2012 primary
annual PM2.5 NAAQS and nonattainment for the 1997 primary
annual PM2.5 NAAQS, the EPA's preferred proposed option is
not to require these areas to adopt any outstanding applicable
requirements for the revoked 1997 primary annual PM2.5
standard. However, the EPA proposes that the approved PSD SIPs for
these areas satisfy the obligation to submit an approvable maintenance
plan for the 2012 primary annual PM2.5 NAAQS under section
110(a)(1).
     For these same areas (i.e., those designated attainment
for the 2012 primary annual PM2.5 NAAQS and nonattainment
for the 1997 primary annual PM2.5 NAAQS), the EPA is also
proposing an alternative anti-backsliding option where these areas
would be required to show maintenance for the 2012 primary annual
PM2.5 NAAQS. This maintenance showing would be due 3 years
after the effective date of designations for the 2012 primary annual
PM2.5 NAAQS. The maintenance showing would contain a
demonstration of continued maintenance of the 2012 primary annual
PM2.5 NAAQS in the area for 10 years from the effective date
of the area's designation as attainment for the 2012 primary annual
PM2.5 NAAQS. The EPA would take further action to specify
the elements of such a maintenance showing should the agency require it
in the final rule. For areas designated nonattainment for the 2012
primary annual PM2.5 NAAQS and also designated nonattainment
for the 1997 annual PM2.5 NAAQS, the EPA is proposing that
these areas continue to implement their approved SIPs for the 1997
annual PM2.5 NAAQS and fulfill any outstanding requirements,
and that they comply with the applicable requirements for the current
2012 primary annual PM2.5 NAAQS. For example, at some time
in the future there may be an area that is reclassified as Serious for
the 1997 PM2.5 NAAQS while also classified as Moderate for
the 2012 PM2.5 NAAQS. In such an area, the lower Serious
area major source threshold of 70 tpy (PTE) would apply. In addition to
these proposed requirements, if a state seeks to revise any measure
already approved into its SIP for a nonattainment area for the 1997
annual PM2.5 NAAQS, the state must meet the requirements of
sections 110(l) and 193, if applicable.
    The EPA notes that Option 2 for 2012 attainment/1997 nonattainment
would

be similar to the approach to revocation of the 1-hour ozone NAAQS
consistent with court decisions and the approach to revocation of the
1997 ozone NAAQS in the final 2008 ozone NAAQS SIP requirements
rule.\331\ The EPA also notes that areas designated nonattainment for
the 2012 primary annual PM2.5 NAAQS would be required to
comply with applicable conformity requirements beginning 1 year after
the effective date of designations for that NAAQS. For transportation
conformity purposes these requirements would include using adequate or
approved motor vehicle emissions budgets for the 1997 annual
PM2.5 NAAQS where they exist until the area has approved or
adequate budgets for the 2012 primary annual PM2.5
NAAQS.\332\ The use of such budgets serves as the appropriate anti-
backsliding measure for transportation conformity purposes. Further
details regarding this option and associated rationale are in Section
X.D of this preamble.
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    \331\ See the final SIP requirements rule for the 2008 ozone
NAAQS at http://www.epa.gov/groundlevelozone/implement.
    \332\ Areas that do not have adequate or approved motor vehicle
emissions budgets for the 1997 annual PM2.5 NAAQS or the
2006 24-hour PM2.5 NAAQS would use one of the two interim
emissions tests required by 40 CFR 93.109(c)(3) and 40 CFR
93.119(b).
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    Lastly, the EPA requests comment on the possible approach of not
revoking the 1997 primary annual PM2.5 NAAQS at this time.
Under this concept, the EPA would not revoke the 1997 primary annual
PM2.5 NAAQS for any purpose at this time. As a result, all
nonattainment and maintenance areas would be required to continue
planning activities associated with the 1997 annual PM2.5
NAAQS such as submitting attainment SIPs and maintenance plans, NNSR,
and transportation and general conformity requirements for the 1997
primary annual PM2.5 NAAQS, in addition to any new
requirements associated with the more health-protective 2012 primary
annual PM2.5 NAAQS. Under this approach the EPA would not
have to establish any anti-backsliding requirements.
    The EPA again notes that if this approach were finalized it would
be the first time that the EPA has not taken some action to reduce the
burden associated with implementing a NAAQS that has been replaced with
a more stringent NAAQS.\333\ If the EPA were to finalize this approach,
it would result in state and local agencies being required to implement
the requirements associated with two primary annual PM2.5
NAAQS. These agencies would be required to continue attainment planning
activities for the 1997 primary annual PM2.5 NAAQS even if
they had air quality data that resulted in their being designated
attainment for the 2012 primary annual PM2.5 NAAQS. State,
local and federal agencies would be required to continue to make
transportation and general conformity determinations for the less
protective 1997 primary annual PM2.5 NAAQS.
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    \333\ As discussed in Section IX.B of this preamble, the EPA has
taken action to revoke previous ozone, SO2 and lead NAAQS
when the previous NAAQS has been revised.
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D. Discussion of Options

    Until the 1997 primary annual PM2.5 NAAQS is revoked,
that NAAQS remains in effect, in parallel with the 2012 primary annual
PM2.5 NAAQS, and continues to apply independently and by its
own terms. The EPA believes that all of the proposed options to revoke
the 1997 primary annual PM2.5 NAAQS are consistent with the
CAA and previous precedent in transitioning from a previous NAAQS to a
new, more stringent NAAQS, and would ensure that attainment areas
continue to attain the revoked NAAQS into the future. If the 1997
primary annual PM2.5 NAAQS is revoked, the EPA is proposing
that the anti-backsliding requirements for the 1997 primary annual
PM2.5 NAAQS, as proposed in this rulemaking, will become
applicable. However, the EPA notes that most of the areas that were
initially designated as nonattainment for the 1997 primary annual
PM2.5 NAAQS where the NAAQS would be revoked have already
been redesignated to attainment (i.e., they are maintenance areas) or
could qualify for redesignation based on current air quality data, and
in such cases their approved maintenance plan for the 1997 primary
annual PM2.5 would prevent backsliding.\334\ Under Option 2
there would be a limited number of nonattainment areas where the 1997
primary annual NAAQS would be revoked and where anti-backsliding
measures would be required. Under all of the proposed options,
conformity would apply in areas that are designated nonattainment for
the more health protective 2012 primary annual PM2.5 NAAQS.
In the case of transportation conformity, adequate or approved motor
vehicle emissions budgets for the 1997 primary annual PM2.5
NAAQS would be used in conformity determinations until motor vehicle
emissions budgets for the 2012 primary annual PM2.5 NAAQS
are found adequate or are approved. Once a NAAQS is revoked in a
nonattainment area, the EPA would not designate or redesignate areas
for that NAAQS after the revocation of that NAAQS except as described
in Option 1. The extent of continued implementation of a revoked
standard derives from administration of anti-backsliding requirements
for that standard.
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    \334\ Based on 2011-13 air quality data, many of the areas that
were initially designated nonattainment for the 1997 annual
PM2.5 NAAQS will have already met the 1997 annual
PM2.5 NAAQS and will have been redesignated to attainment
by the time it is revoked (projected to be in or around April 2016),
and thus after revocation of the 1997 primary annual
PM2.5 NAAQS, the number of areas with 1997 anti-
backsliding requirements will be correspondingly reduced.
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    Under Option 1, the 1997 primary annual PM2.5 NAAQS
would be revoked only in areas that have attained the 1997 annual
PM2.5 NAAQS and have been redesignated to attainment with an
approved section 175A maintenance plan for the 1997 primary annual
PM2.5 NAAQS; under Option 2, many of the areas where the
1997 primary annual NAAQS would be revoked would have been redesignated
to attainment with an approved maintenance plan. The EPA also
anticipates that states will continue to request that areas be
redesignated to attainment and the EPA will continue to act on those
requests under Option 2. As a result the EPA anticipates that a number
of such requests will be approved prior to the point in time that the
EPA has proposed for the revocations to become effective (i.e., 1 year
after the effective date of designations for the 2012 primary annual
PM2.5 NAAQS). Therefore, the number of nonattainment areas
for the 1997 primary annual PM2.5 NAAQS will continue to
decrease and fewer areas will be required to comply with anti-
backsliding requirements, and a correspondingly larger number of areas
will be required to continue to implement their approved section 175A
maintenance plan for the 1997 primary annual PM2.5 NAAQS.
    It should also be noted that, for either proposed option, after the
effective date of any revocation of the 1997 primary annual
PM2.5 NAAQS, transportation and general conformity
determinations would continue to be required in areas that are
designated nonattainment for the 1997 secondary annual PM2.5
NAAQS until such areas are redesignated to attainment pursuant to the
requirements of section 107(d)(3). Areas that are initially designated
as nonattainment for the 2012 primary annual NAAQS are subject to
transportation and general conformity requirements after the end of the
grace period that ends 1 year after the effective date of designations
for the 2012 primary annual PM2.5 NAAQS. See further
information for how conformity will be implemented for the 2012
PM2.5 NAAQS in Section IX.B of this preamble. Under Options
1 and 2 the

timing that the EPA is proposing means that any area that was
previously a 1997 annual PM2.5 NAAQS nonattainment area, but
has been redesignated to attainment for the 1997 annual
PM2.5 NAAQS by the time of revocation of the 1997 primary
annual PM2.5 NAAQS (e.g., April 2016 for most areas), will
not be subject to the anti-backsliding requirements for the 1997 annual
PM2.5 NAAQS. This is because when an area has been
redesignated to attainment for a PM2.5 NAAQS while that
NAAQS is in effect, it has fulfilled all applicable requirements for
that NAAQS, including applicable anti-backsliding requirements for the
1997 annual PM2.5 NAAQS. The area is, therefore, not subject
to anti-backsliding requirements for the revoked 1997 primary annual
PM2.5 NAAQS. These areas are required instead to implement
their approved CAA section 175A maintenance plan for the 1997 primary
annual PM2.5 NAAQS and implement a PSD program for this
NAAQS, if they are designated attainment for the 2012 primary annual
PM2.5 NAAQS.335 336 Revisions to the approved
maintenance plan can only be made if the revisions meet the
requirements of section 110(l) and, if applicable, section 193. The EPA
proposes that these areas not be required to submit a second 10-year
maintenance plan for the 1997 primary annual PM2.5 NAAQS
because there is no justification for additional maintenance plan
burdens to be imposed on these areas solely because at one time they
were designated nonattainment under the revoked 1997 primary annual
PM2.5 NAAQS. Not requiring a second 10-year maintenance plan
for these areas would help to minimize the burden associated with
preparing SIPs for a succession of NAAQS of increasing stringency.
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    \335\ Areas initially designated as attainment for the 1997
annual PM2.5 NAAQS would also be required to continue to
implement a PSD program unless an area was designated nonattainment
for the 2012 primary annual PM2.5 NAAQS. Such an area
would be required to implement a NNSR program for that NAAQS.
    \336\ Areas designated nonattainment for the 2012 primary annual
PM2.5 NAAQS would implement a NNSR program for that
NAAQS.
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    As explained previously, for areas redesignated to attainment under
Options 1 and 2, the section 175A maintenance plan for the 1997 primary
annual PM2.5 NAAQS satisfies the anti-backsliding
requirements of these areas. The EPA believes that for these areas any
further 110(a)(1) maintenance plan requirement under the 2012 primary
annual PM2.5 NAAQS for areas designated attainment for that
NAAQS would be unnecessarily burdensome.
    For Option 2, the EPA is applying a general principle to apply
transition requirements depending on how the area is designated--
attainment or nonattainment--for the 2012 primary annual
PM2.5 NAAQS, while taking into account the area's status
with respect to the 1997 primary annual PM2.5 NAAQS. For
those areas which have already incorporated measures into their
approved SIPs that satisfy the nonattainment requirements for that
standard, section 110(l) functions to require continued implementation
of such measures unless revised in accordance with its provisions.
    Under Option 2, the EPA is proposing as one alternative that areas
designated attainment for the 2012 primary annual PM2.5
NAAQS and nonattainment for the 1997 annual PM2.5 NAAQS (as
of revocation of the 1997 primary annual PM2.5 NAAQS) not be
required to adopt any outstanding applicable requirements for the
revoked 1997 primary annual standard. This approach is similar to the
approach followed in the transition from the 1-hour ozone NAAQS to the
1997 ozone NAAQS. However, instead of submitting a maintenance plan the
EPA is also proposing that the approved PSD SIPs for these areas
satisfy the obligation to submit an approvable maintenance plan for the
2012 primary annual PM2.5 NAAQS under section 110(a)(1).
This is similar to what the EPA finalized for the transition from the
1997 ozone NAAQS to the 2008 ozone NAAQS.\337\ The EPA's rationale for
this approach is as follows: Areas designated attainment for the 2012
primary annual PM2.5 NAAQS and nonattainment for the 1997
primary annual PM2.5 NAAQS (as of revocation of the 1997
primary annual PM2.5 NAAQS) have already attained the most
stringent existing standard. These areas thus have developed
nonattainment plans that in combination with federal measures and
emissions controls in upwind areas have produced sufficient emissions
reductions to achieve the more protective 2012 primary annual
PM2.5 NAAQS. They remain subject to the 1997 nonattainment
area requirements already approved into the SIP, which can be revised
only upon a showing that such revision is consistent with sections
110(l) and 193, if applicable. At this time, and given the succession
of NAAQS of increasing stringency that has occurred, the EPA believes
that the burden of developing an approvable maintenance plan for the
2012 primary annual PM2.5 NAAQS would outweigh any
compensating benefit for an area that is already attaining that more
stringent NAAQS and that is subject to prior nonattainment requirements
which are already incorporated into the SIP.
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    \337\ See the the final SIP requirements rule for the 2008 ozone
NAAQS at http://www.epa.gov/groundlevelozone/implement.html.
---------------------------------------------------------------------------

    Under Option 2, the EPA is also proposing, for areas that are
attainment for the 2012 primary annual PM2.5 NAAQS, that the
NNSR anti-backsliding requirement(s) for the 1997 annual
PM2.5 NAAQS cease to apply, since PSD will then be in
effect. The state may request that the corresponding NSR requirements
be removed entirely, rather than be retained in the SIP as a
maintenance plan contingency measure.\338\ Areas that are designated
nonattainment for the more stringent 2012 primary annual
PM2.5 NAAQS will be subject to NNSR and other nonattainment
requirements for their classification under the more stringent 2012
primary annual PM2.5 NAAQS.
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    \338\ See 40 CFR 51.905(a)(3), the comparable provision for
transitions from the 1-hour NAAQS to the 1997 ozone NAAQS, which
allows such areas to request that the 1-hour NNSR provisions be
removed from the SIP.
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    The revocation of the 1-hour ozone NAAQS and the associated anti-
backsliding provisions were the subject of past litigation. In its
December 2006 decision on that challenge, as modified following
rehearing, the Court held with respect to the anti-backsliding approach
for conformity that 1-hour ozone motor vehicle emissions budgets must
be used in transportation conformity determinations for the more
protective 1997 ozone NAAQS where such SIP motor vehicle emissions
budgets have been found adequate or approved, until SIP motor vehicle
emissions budgets for the 1997 ozone NAAQS are available.\339\ In
addition, the Court affirmed more broadly that in order for
transportation conformity determinations to fulfill the requirements of
CAA section 176(c)(1), motor vehicle emissions budgets for a prior
NAAQS must be used in transportation conformity determinations under a
revised NAAQS until emissions budgets for the revised NAAQS are either
found adequate or are approved, but that conformity determinations need
not be made for a revoked standard. Therefore, areas designated
nonattainment for the 2012 primary annual PM2.5 NAAQS that
have adequate or approved SIP budgets for the 1997 annual
PM2.5 NAAQS must continue to use such budgets in
transportation conformity determinations until budgets for the

2012 primary annual PM2.5 NAAQS are found adequate or are
approved.\340\
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    \339\ See South Coast Air Quality Management District v. EPA,
472 F.3d at 882 (D.C. Cir. 2006).
    \340\ Areas that do not have adequate or approved motor vehicle
emissions budgets for the 1997 annual PM2.5 NAAQS or the
2006 24-hour PM2.5 NAAQS would use one of the two interim
emissions tests requied by 40 CFR 93.109(c)(3) and 40 CRR 93.119(b).
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    With regard to general conformity, the D.C. Circuit Court did not
address the need for specific anti-backsliding measures in its initial
decision or in the modified decision on the South Coast litigation.
Therefore, if the EPA finalizes either Option 1 or 2 and revokes the
1997 primary annual PM2.5 NAAQS, general conformity
determinations will be required in nonattainment areas for the 2012
primary annual NAAQS as required by section 176(c)(5) to ensure that
the action of federal agencies do not cause a violation of that NAAQS,
make an existing violation worse or delay timely attainment of the
NAAQS or an interim milestone.\341\ The EPA believes that revoking the
1997 primary annual PM2.5 NAAQS under Option 1 or 2 is
logical because it would result in only one primary annual
PM2.5 NAAQS--the 2012 primary annual PM2.5
NAAQS--applying for purposes of transportation and general conformity
in most areas, after the end of the 1-year conformity grace period that
applies to newly designated nonattainment areas. (CAA section
176(c)(6)).
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    \341\ It should be noted that some areas will remain designated
nonattainment for 1997 secondary annual PM2.5 NAAQS. Such
areas will remain subject to transportation and general conformity
for that NAAQS until such time that they are redesignated to
attainment for that NAAQS pursuant to the requirements of section
107(d)(3).
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    Areas that are attaining the more health protective 2012 primary
annual PM2.5 NAAQS would no longer have to expend resources
to make conformity determinations for any of the current primary annual
PM2.5 NAAQS after the 1997 primary annual PM2.5
NAAQS is revoked and the area is redesignated as attainment for the
1997 secondary annual PM2.5 NAAQS. Some of these areas would
be required to continue to make conformity determinations for the 2006
24-hour PM2.5 NAAQS and based on 2011-13 air quality data
two areas would be required to make conformity determinations for the
1997 24-hour PM2.5 NAAQS. It should be noted that any areas
that are attaining the more health protective 2012 primary annual NAAQS
are also necessarily attaining the less stringent 1997 annual
PM2.5 NAAQS by a wide margin. Therefore, the options of this
proposal would provide a seamless transition from demonstrating
conformity for the 1997 annual PM2.5 NAAQS to demonstrating
conformity for the more stringent 2012 primary annual PM2.5
NAAQS.
    Areas designated nonattainment for the 2012 primary annual
PM2.5 NAAQS will likely need the full 1-year grace period
provided in section 176(c)(6) to complete the required initial
transportation conformity determination. Those areas that were
designated as either nonattainment or maintenance for the 1997 annual
PM2.5 NAAQS at the time of designation as nonattainment for
the 2012 primary annual PM2.5 NAAQS will need certainty as
to the specific requirements for that conformity determination. For
example they need to know what analysis years must be addressed and, if
the boundaries for the PM2.5 NAAQS are different, they need
to know whether to address conformity for both areas and which test or
tests would apply.
    The EPA seeks comment on the options proposed in the preceding
discussion regarding revoking the 1997 primary annual PM2.5
standard, as well as on whether the agency should take no action to
revoke the standard as this time.

XI. Environmental Justice Considerations

    The EPA believes the human health or environmental risk addressed
by this action will not have disproportionately high and adverse human
health or environmental effects on minority, low-income, or indigenous
populations because it would not negatively affect the level of
protection provided to human health or the environment under the
PM2.5 NAAQS. When promulgated, these proposed regulations
will clarify the state implementation plan requirements and the NNSR
permitting requirements to be met by states in order to attain the
PM2.5 NAAQS as expeditiously as practicable. These
requirements are designed to protect all segments of the general
population. The EPA included specific discussion in this preamble about
actions that could be considered for the protection of minority, low-
income or indigenous populations in Section IV.D.6 on Moderate area
attainment plan control strategies; Section VI.D.7 on Serious area
attainment plan control strategies; and Section IX.G, measures to
ensure appropriate protections for overburdened populations. In
addition, as part of the consultation activities conducted in
developing this rule, the EPA participated in training and outreach
activities with representatives from environmental justice
organizations in a March 2014 conference held in Research Triangle
Park, NC titled, ``Clean Air Act Rulemaking and Permitting Training for
EJ Communities.'' These proposed regulations are designed to protect
and enhance the health and safety of these and other populations, and
they will not adversely affect the health or safety of minority, low-
income or indigenous populations.

XII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted
to the Office of Management and Budget (OMB) for review because it
raises novel policy issues. Any changes made in response to OMB
recommendations have been documented in the docket.\342\
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    \342\ Note that a regulatory impact analysis evaluating the
costs and benefits associated with attaining the 2012
PM2.5 NAAQS was released at the time the NAAQS review was
finalized. See ``Regulatory Impact Analysis for the Final Revisions
to the National Ambient Air Quality Standards for Particulate
Matter.'' U.S. Environmental Protection Agency, Office of Air
Quality and Planning Standards, Health and Environmental Impacts
Division, February 28, 2013. EPA-452/R-12-005.
---------------------------------------------------------------------------

B. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the PRA. The Information Collection Request (ICR) document
prepared by the EPA has been assigned the EPA ICR number 2258.03, OMB
Control No. 2060-0611. You can find a copy of the ICR in the docket for
this rule, and it is briefly summarized here.
    The EPA is proposing this PM2.5 NAAQS SIP Requirements
Rule to describe the CAA requirements that must be met by states with
nonattainment areas required to develop attainment plans for attaining
and maintaining the NAAQS. The intended effect of the SIP Requirements
Rule is to provide certainty to states regarding their planning
obligations such that states may begin SIP development. Only states
with nonattainment areas are required to submit SIPs under this rule.
    For purposes of analysis of the estimated paperwork burden, the EPA
assumed there were 21 existing nonattainment areas for the 1997 and
2006 PM2.5 NAAQS, and 15 hypothetical, newly-designated
nonattainment areas.\343\ The attainment

plan requirements would appear as 40 CFR 51.1000 through 51.1015 which
implement CAA subsections 172(c)(1) and (2), and 189(a)(1)(B) and (C),
189(b)(1)(A) and (B) and 189(c). Some states have new nonattainment
areas and some states should already have information from emission
sources, as facilities should have provided this information to meet
1997 and 2006 PM2.5 NAAQS SIP requirements, operating
permits and/or emissions reporting requirements. Such information does
not generally reveal the details of production processes. But, to the
extent it may, confidential business information for the affected
facilities is protected. Specifically, submissions of emissions and
control efficiency information that is confidential, proprietary and
trade secret and is not emission data is protected from disclosure
under the requirements of subsections 503(e) and 114(c) of the CAA.
---------------------------------------------------------------------------

    \343\ These hypothetical nonattainment areas were developed
based on 2010-12 air quality data and state recommendations. Actual
nonattainment designations and boundaries are based on the most
recent, complete air quality data available.
---------------------------------------------------------------------------

    The annual state burden for this information collection for the 15
hypothetical newly designated 2012 PM2.5 nonattainment
areas, averaged over the first 3 years of this ICR, is estimated to be
a total of 54,000 labor hours per year at an annual labor cost of $3.2
million (present value) over the 3-year period, or approximately
$649,000 per state for the 5 state respondents. The average annual
reporting burden is approximately 3,600 hours per response, with
approximately 3 responses per state for 15 state responses. There are
no capital or operating and maintenance costs associated with the
proposed rule requirements. Burden is defined at 5 CFR 1320.3(b).
    The annual state burden for this information collection for the 21
existing nonattainment areas for the 1997 and 2006 PM2.5
NAAQS, averaged over the first 3 years of this ICR, is estimated to be
a total of 43,400 labor hours per year at an annual labor cost of $2.6
million (present value) over the 3-year period, or approximately
$370,000 per state for the 7 state respondents. The average annual
reporting burden is approximately 2,000 hours per response, with
approximately 3 responses per state for 21 state responses. There are
no capital or operating and maintenance costs associated with the
proposed rule requirements. Burden is defined at 5 CFR 1320.3(b).
    An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for the
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
    Submit your comments on the agency's need for this information, the
accuracy of the provided burden estimates and any suggested methods for
minimizing respondent burden to the EPA using the docket identified at
the beginning of this rule. You may also send your ICR-related comments
to OMB's Office of Information and Regulatory Affairs via email to
<EMAIL_ADDRESS>Attention: Desk Officer for the EPA.
Since OMB is required to make a decision concerning the ICR between 30
and 60 days after receipt, OMB must receive comments no later than
April 22, 2015. The EPA will respond to any ICR-related comments in the
final rule.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any regulation subject
to notice-and-comment rulemaking requirements under the Administrative
Procedures Act or any other statute unless the agency certifies the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations and small governmental jurisdictions.
    For purposes of assessing the impacts of this rule on small
entities, small entity is defined as: (1) A small business as defined
in the Small Business Administration's (SBA) regulations at 13 CFR
121.201; (2) a small governmental jurisdiction that is a government of
a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
    After considering the economic impacts of this proposed rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. This
proposed rule will not impose any requirements directly on small
entities. Entities potentially affected directly by this proposal
include state, local and tribal governments and none of these
governments are small governments. Other types of small entities are
not directly subject to the requirements of this rule. The EPA
continues to be interested in the potential impacts of the proposed
rule on small entities and welcomes comments on issues related to such
impacts.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action imposes no enforceable duty on any
state, local or tribal governments or the private sector. The CAA
imposes the obligation for states to submit attainment plans to
implement the PM2.5 NAAQS. In this rule, the EPA is
clarifying those requirements. Therefore, this action is not subject to
the requirements of sections 202, 203, and 205 of the UMRA.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government, as
specified in Executive Order 13132. The requirement to submit
attainment plans to meet a PM2.5 NAAQS is imposed by the
CAA. This proposed rule, if made final, would interpret those
requirements as they apply to current and future PM2.5
NAAQS. Thus, Executive Order 13132 does not apply to these proposed
regulations.
    In the spirit of Executive Order 13132 and consistent with the EPA
policy to promote communications between the EPA and state and local
governments, the EPA specifically solicits comments on this proposed
action from state and local officials. In addition, the EPA intends to
meet with organizations representing state and local officials during
the comment period for this action.

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

    This proposed action does not have tribal implications, as
specified in Executive Order 13175 (65 FR 67249, November 9, 2000). It
would not have a substantial direct effect on one or more Indian
tribes. Furthermore, these proposed regulation revisions do not affect
the relationship or distribution of power and responsibilities between
the federal government and Indian tribes. The CAA and the TAR establish
the relationship of the federal government and tribes in characterizing
air quality and developing plans to attain the NAAQS, and these
revisions to the regulations do nothing to modify that

relationship. Thus, Executive Order 13175 does not apply to this
action.
    Although Executive Order 13175 does not apply to this action, the
EPA solicits comment on this proposed action from tribal officials. The
EPA also intends to offer to consult with any tribal government to
discuss this proposal.

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

    The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. This action is not subject to
Executive Order 13045 because it implements a previously promulgated
health or safety-based federal standard established pursuant to the
CAA.
    These proposed regulatory provisions are designed to help implement
the current and future PM2.5 NAAQS, promulgated to protect
the health and welfare of individuals, including children, who are
susceptible to the adverse effects of exposure to unhealthy levels of
ambient PM2.5.

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

    This action is not a ``significant energy action'' as defined in
Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not
likely to have a significant adverse effect on the supply,
distribution, or use of energy.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272
note) directs the EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures and business practices) that are developed or
adopted by voluntary consensus standards bodies. NTTAA directs the EPA
to provide Congress, through OMB, explanations when the agency decides
not to use available and applicable voluntary consensus standards.
    This proposed rulemaking does not involve technical standards.
Therefore, the EPA is not considering the use of any voluntary
consensus standards.

J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

    The EPA believes the human health or environmental risk addressed
by this action will not have disproportionately high and adverse human
health or environmental effects on minority, low-income, or indigenous
populations. The results of this evaluation are contained in Section XI
of this preamble.

K. Determination Under Section 307(d)

    Pursuant to sections 307(d)(1)(E) and 307(d)(1)(V) of the CAA, the
Administrator proposes to determine that this action is subject to the
provisions of section 307(d). Under section 307(d)(1)(V), the
provisions of section 307(d) apply to ``such other actions as the
Administrator may determine.''

Statutory Authority

    The statutory authority for this action is provided by 42 U.S.C.
7403, 7407, 7410, and 7601.

List of Subjects

40 CFR Part 50

    Environmental protection, Air pollution control, Intergovernmental
relations, Particulate matter.

40 CFR Part 51

    Environmental protection, Air pollution control, Intergovernmental
relations, Particulate matter.

40 CFR Part 93

    Environmental protection, Air pollution control, Intergovernmental
relations, Particulate matter.

    Dated: March 10, 2015.
Gina McCarthy,
Administrator.

    For the reasons stated in the preamble, Title 40, Chapter I of the
Code of Federal Regulations is proposed to be amended as follows:

PART 50--NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY
STANDARDS

0
1. The authority citation for part 50 continues to read as follows:

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

0
2. In Sec.  50.13, add paragraph (d) to read as follows:

Sec.  50.13  National primary and secondary ambient air quality
standards for PM2.5.

* * * * *
    (d) The standards set forth in this section will remain applicable
to all areas notwithstanding the promulgation of the 2012 primary
annual PM2.5 national ambient air quality standards (NAAQS)
in Sec.  50.18. The 1997 primary annual PM2.5 NAAQS set
forth in this section will no longer apply to an area 1 year after the
effective date of the designation of that area, pursuant to section 107
of the Clean Air Act, for the primary annual PM2.5 NAAQS set
forth in Sec.  50.18; except that for areas designated nonattainment
for the 1997 annual PM2.5 NAAQS set forth in this section as
of 1 year after the effective date of the designations for the primary
annual PM2.5 NAAQS established in Sec.  50.18, the
requirements applicable to the 1997 annual PM2.5 NAAQS set
forth in this section will apply until the effective date of an area's
redesignation to attainment for the 1997 annual NAAQS pursuant to the
requirements of section 107 of the Clean Air Act. The 1997 secondary
annual PM2.5 NAAQS and the 1997 24-hour PM2.5
NAAQS shall remain in effect.

PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF
IMPLEMENTATION PLANS

0
3. The authority citation for part 51 continues to read as follows:

    Authority: 23 U.S.C. 101; 42 U.S.C. 7401-7671q.

Subpart I--Review of New Sources and Modifications

0
4. In Sec.  51.165:
0
a. Revise paragraphs (a)(1)(iv)(A)(1), (a)(1)(x)(A), and
(a)(1)(xxxvii)(C)(2);
0
b. Remove paragraphs (a)(1)(xxxvii)(C)(3), and (4); and
0
d. Revise paragraphs (a)(2)(i) and (a)(2)(ii)(A).
    The revisions read as follows:

Sec.  51.165  Permit requirements.

    (a) * * *
    (1) * * *
    (iv)(A) * * *
    (1) Any stationary source of air pollutants that emits, or has the
potential to emit, 100 tons per year or more of any regulated NSR
pollutant (as defined in paragraph (a)(1)(xxxvii) of this section),
except that lower emissions thresholds shall apply in areas subject to
subpart 2, subpart 3, or subpart 4 of part D, title I of the Act,
according to paragraphs (a)(1)(iv)(A)(1)(i) through (viii) of this
section.
    (i) 50 tons per year of volatile organic compounds in any serious
ozone nonattainment area.

    (ii) 50 tons per year of volatile organic compounds in an area
within an ozone transport region, except for any severe or extreme
ozone nonattainment area.
    (iii) 25 tons per year of volatile organic compounds in any severe
ozone nonattainment area.
    (iv) 10 tons per year of volatile organic compounds in any extreme
ozone nonattainment area.
    (v) 50 tons per year of carbon monoxide in any serious
nonattainment area for carbon monoxide, where stationary sources
contribute significantly to carbon monoxide levels in the area (as
determined under rules issued by the Administrator).
    (vi) 70 tons per year of PM10 in any serious
nonattainment area for PM10.
    (vii) 70 tons per year of PM2.5 in any serious
nonattainment area for PM2.5.
    (viii) 70 tons per year of any precursor for PM2.5 in
any serious nonattainment area for PM2.5.
* * * * *
    (x)(A) Significant means, in reference to a net emissions increase
or the potential of a source to emit any of the following pollutants, a
rate of emissions that would equal or exceed any of the following
rates:

Pollutant Emission Rate

Carbon monoxide: 100 tons per year (tpy)
Nitrogen oxides: 40 tpy
Sulfur dioxide: 40 tpy
Ozone: 40 tpy of volatile organic compounds or nitrogen oxides
Lead: 0.6 tpy
PM10: 15 tpy
PM2.5: 10 tpy of direct PM2.5 emissions; 40 tpy
of sulfur dioxide emissions; 40 tpy of nitrogen oxide emissions; 40 tpy
of VOC emissions;
* * * * *
    (xxxvii) * * *
    (C) * * *
    (2) Sulfur dioxide, nitrogen oxides, volatile organic compounds and
ammonia are precursors to PM2.5 in any PM2.5
nonattainment area, unless the State demonstrates to the
Administrator's satisfaction or the EPA demonstrates that major
stationary sources of a particular precursor do not contribute
significantly to PM2.5 levels that exceed the
PM2.5 ambient standards in a particular area.
* * * * *
    (2) Applicability procedures. (i) Each plan shall adopt a
preconstruction review program to satisfy the requirements of sections
172(c)(5) and 173 of the Act for any area designated nonattainment for
any national ambient air quality standard under subpart C of 40 CFR
part 81. Such a program shall apply to any new major stationary source
or major modification that is major for the pollutant (as defined in
paragraph (a)(1)(xxxvii) of this section) for which the area is
designated nonattainment under section 107(d)(1)(A)(i) of the Act, if
the stationary source or modification would locate anywhere in the
designated nonattainment area. Different pollutants, including
individual precursors, are not summed to determine applicability of a
major stationary source or major modification.
    (ii) * * *
    (A) Except as otherwise provided in paragraphs (a)(2)(iii) and (iv)
of this section, and consistent with the definition of major
modification contained in paragraph (a)(1)(v)(A) of this section, a
project is a major modification for a regulated NSR pollutant (as
defined in paragraph (a)(1)(xxxvii) of this section), if it causes two
types of emissions increases--a significant emissions increase (as
defined in paragraph (a)(1)(xxvii) of this section), and a significant
net emissions increase (as defined in paragraphs (a)(1)(vi) and (x) of
this section). The project is not a major modification if it does not
cause a significant emissions increase. If the project causes a
significant emissions increase, then the project is a major
modification only if it also results in a significant net emissions
increase.
* * * * *
0
5. In Appendix S to part 51:
0
a. Revise paragraph II.A.4.(i)(a) introductory text;
0
b. Add paragraphs II.A.4.(a)(7) and (8); and
0
c. Revise paragraphs II.A.10.(i) and II.A.31.(ii)(b)(2).
    The revisions and addition read as follows:

Appendix S to Part 51--Emission Offset Interpretative Ruling

* * * * *
    II. * * *
    A. * * *
    4. (i) * * *
    (a) Any stationary source of air pollutants which emits, or has
the potential to emit, 100 tons per year or more of a regulated NSR
pollutant (as defined in paragraph II.A.31 of this Ruling), subject
to regulation under the Act, except that lower emissions thresholds
shall apply in areas subject to subpart 2, subpart 3, or subpart 4
of part D, title I of the Act, according to paragraphs
II.A.4(i)(a)(1) through (6) of this ruling.
* * * * *
    (7) 70 tons per year of PM2.5 in any serious
nonattainment area for PM2.5.
    (8) 70 tons per year of any PM2.5 precursor (as
defined in paragraph II.A.31 of this Ruling) in any Serious
nonattainment area for PM2.5.
* * * * *
    10. (i) Significant means, in reference to a net emissions
increase or the potential of a source to emit any of the following
pollutants, a rate of emissions that would equal or exceed any of
the following rates:

Pollutant and Emissions Rate

Carbon monoxide: 100 tons per year (tpy)
Nitrogen oxides: 40 tpy
Sulfur dioxide: 40 tpy
Ozone: 40 tpy of volatile organic compounds or nitrogen oxides
Lead: 0.6 tpy
Particulate matter: 25 tpy of particulate matter emissions
PM10: 15 tpy
PM2.5: 10 tpy of direct PM2.5 emissions; 40
tpy of sulfur dioxide emissions; 40 tpy of nitrogen oxides emissions
* * * * *
    31. * * *
    (ii) * * *
    (b) * * *
    (2) Sulfur dioxide and nitrogen oxides are precursors to
PM2.5 in all PM2.5 nonattainment areas.
* * * * *
0
6. Revise subpart Z to read as follows:

Subpart Z--Provisions for Implementation of PM2.5
National Ambient Air Quality Standards

Sec.
51.1000 Definitions.
51.1001 Applicability of part 51.
51.1002 Classifications.
51.1003 Attainment plan submittals and due dates.
51.1004 Attainment dates.
51.1005 Attainment date extensions.
51.1006 Requirements for demonstrating insignificant contribution of
PM2.5 precursors.
51.1007 Requirements for de minimis source category determinations
for direct PM2.5 and PM2.5 precursors.
51.1008 Emissions inventory requirements.
51.1009 Moderate area attainment plan control strategy requirements.
51.1010 Serious area attainment plan control strategy requirements.
51.1011 Attainment demonstration and modeling requirements.
51.1012 Reasonable further progress (RFP) requirements.
51.1013 Quantitative milestone requirements.
51.1014 Contingency measures requirements.
51.1015 Clean data requirements.

Sec.  51.1000  Definitions.

    The following definitions apply for purposes of this subpart. Any
term not defined herein shall have the meaning as defined in 40 CFR
51.100 or Clean Air Act section 302.
    Act means the Clean Air Act as codified at 42 U.S.C. 7401-7671q
(2003).

    Additional feasible measure is any control measure that otherwise
meets the definition of ``best available control measure'' (BACM) but
can only be implemented in whole or in part beginning 4 years after the
date of reclassification of an area as Serious and no later than the
statutory attainment date for the area.
    Additional reasonable measure is any control measure that otherwise
meets the definition of ``reasonably available control measure'' (RACM)
but can only be implemented in whole or in part during the period
beginning 4 years after the date of designation of a nonattainment area
and no later than the end of the sixth calendar year following the date
of designation of the area.
    Applicable annual standard is the annual PM2.5 NAAQS
established, revised, or retained as a result of a particular
PM2.5 NAAQS review.
    Applicable attainment date means the latest statutory date by which
an area is required to attain a particular PM2.5 NAAQS,
unless EPA has approved an attainment plan for the area to attain such
NAAQS, in which case the applicable attainment date is the date
approved under such attainment plan. If EPA grants an extension of an
approved attainment date, then the applicable attainment date for the
area shall be the extended date.
    Applicable 24-hour standard is the 24-hour PM2.5 NAAQS
established, revised, or retained as a result of a particular
PM2.5 NAAQS review.
    Attainment projected inventory means the projected emissions of
direct PM2.5 and all PM2.5 precursors from
sources included in the base year inventory, and from any additional
sources of such emissions expected within the boundaries of the
nonattainment area by the projected attainment date for the area.
    Base year inventory means the actual emissions of direct
PM2.5 and all PM2.5 precursors from all sources
within the boundaries of a nonattainment area in one of the 3 years
used for purposes of designations or another technically appropriate
year.
    Benchmark RFP analysis means the analysis submitted as part of the
RFP plan for a PM2.5 nonattainment area that requires
generally linear emissions reductions in direct PM2.5 and in
each PM2.5 precursor from the base year through the
projected attainment year.
    Best available control measure (BACM) is any technologically and
economically feasible control measure that can be implemented in whole
or in part within 4 years after the date of reclassification of a
PM2.5 nonattainment area and that generally can achieve
greater permanent and enforceable emissions reductions in direct
PM2.5 emissions and/or emissions of PM2.5
precursors from sources in the area than can be achieved through the
implementation of RACM on the same source(s). BACM includes best
available control technology (BACT).
    Date of designation means the effective date of a PM2.5
area designation as promulgated by the Administrator.
    Date of reclassification means the effective date of a
PM2.5 area reclassification from Moderate to Serious as
promulgated by the Administrator.
    Direct PM2.5 emissions means solid particles emitted directly from
an air emissions source or activity, or gaseous emissions or liquid
droplets from an air emissions source or activity which condense to
form particulate matter at ambient temperatures. Direct
PM2.5 emissions include filterable and condensable
PM2.5 emissions composed of elemental carbon, directly
emitted organic carbon, directly emitted sulfate, directly emitted
nitrate, and other inorganic particles (including but not limited to
crustal material, metals, and sea salt).
    Existing control measure means any federally enforceable national,
state, or local control measure that results in reductions in direct
PM2.5 emissions or emissions of PM2.5 precursors
in a nonattainment area in that state.
    Implemented means adopted by the state and fully approved into the
SIP by EPA for the nonattainment area; built, installed, and/or
otherwise physically manifested; and, fully complied with by the
affected sources.
    Most stringent measure (MSM) is any permanent and enforceable
control measure that achieves the most stringent emissions reductions
in direct PM2.5 emissions and/or emissions of
PM2.5 precursors from among those control measures which are
either included in any other SIP for any NAAQS or have been achieved in
practice by any state and that can feasibly be implemented in the
relevant PM2.5 NAAQS nonattainment area.
    PM2.5 design value (DV) for a PM2.5 nonattainment area
is the highest of the three-year average concentrations calculated for
the ambient air quality monitors in the area, in accordance with 40 CFR
part 50, appendix N.
    PM2.5 NAAQS are the fine particulate matter National Ambient Air
Quality Standards codified at 40 CFR part 50.
    PM2.5 precursors are sulfur dioxide (SO2), oxides of
nitrogen (NOX), volatile organic compounds (VOC), and
ammonia (NH3).
    Reasonably available control measure (RACM) is any technologically
and economically feasible measure that can be implemented in whole or
in part within 4 years after the date of designation of a
PM2.5 nonattainment area and that achieves permanent and
enforceable reductions in direct PM2.5 emissions and/or
PM2.5 precursor emissions from sources in the area. RACM
includes reasonably available control technology (RACT).
    Reasonable further progress (RFP) means such annual incremental
reductions in emissions of direct PM2.5 and PM2.5
precursors regulated in the attainment plan as are required for the
purpose of ensuring attainment of the applicable PM2.5 NAAQS
in a nonattainment area by the applicable attainment date.
    Subpart 1 means subpart 1 of part D of title I of the Act.
    Subpart 4 means subpart 4 of part D of title I of the Act.

Sec.  51.1001  Applicability of part 51.

    The provisions in subparts A through X of this part apply to areas
for purposes of the PM2.5 NAAQS to the extent they are not
inconsistent with the provisions of this subpart.

Sec.  51.1002  Classifications.

    (a) Initial classification as Moderate PM2.5 nonattainment area.
Any area designated nonattainment for a PM2.5 NAAQS shall be
classified at the time of such designation, by operation of law, as a
Moderate PM2.5 nonattainment area.
    (b) Reclassification as Serious PM2.5 nonattainment area. A
Moderate nonattainment area shall be reclassified to Serious under the
following circumstances:
    (1) The EPA shall reclassify as Serious through notice-and-comment
rulemaking any Moderate PM2.5 nonattainment area that the
EPA determines cannot practicably attain a particular PM2.5
NAAQS by the applicable Moderate area attainment date.
    (2) A Moderate PM2.5 nonattainment area shall be
reclassified by operation of law as a Serious nonattainment area if the
EPA finds through notice-and-comment rulemaking that the area failed to
attain a particular PM2.5 NAAQS by the applicable Moderate
area attainment date.

Sec.  51.1003  Attainment plan submittals and due dates.

    (a) Nonattainment areas initially classified as Moderate.
    (1) For any area designated as nonattainment and initially
classified as Moderate for a PM2.5 NAAQS, the

state(s) shall submit a Moderate area attainment plan that meets all of
the following requirements:
    (i) Emissions inventory requirements set forth at Sec.
51.1008(a)(1);
    (ii) Emissions inventory requirements set forth at Sec.
51.1008(a)(2);
    (iii) Moderate area attainment plan control strategy requirements
set forth at Sec.  51.1009;
    (iv) Attainment demonstration and modeling requirements set forth
at Sec.  51.1011;
    (v) Reasonable Further Progress (RFP) requirements set forth at
Sec.  51.1012;
    (vi) Quantitative milestone requirements set forth at Sec.
51.1013;
    (vii) Contingency measure requirements set forth at Sec.  51.1014;
and,
    (viii) Nonattainment new source review plan requirements pursuant
to section 189(a)(1)(A) and section 172(c)(5) of the CAA.
    (2) The state(s) shall submit its Moderate area attainment plan to
EPA no later than 18 months from the date of designation of the area.
    (b) Nonattainment areas reclassified to Serious.
    (1) For any nonattainment area reclassified to Serious for a
PM2.5 NAAQS under Sec.  51.1002(b), in addition to meeting
the Moderate area attainment plan submittal requirements set forth at
Sec.  51.1003(a), the state(s) shall submit a Serious area attainment
plan that meets all of the following requirements:
    (i) Emissions inventory requirements set forth at Sec.
51.1008(b)(1);
    (ii) Emissions inventory requirements set forth at Sec.
51.1008(b)(2);
    (iii) Serious area attainment plan control strategy requirements
set forth at Sec.  51.1010;
    (iv) Attainment demonstration and modeling requirements set forth
at Sec.  51.1011;
    (v) Reasonable Further Progress (RFP) requirements set forth at
Sec.  51.1012;
    (vi) Quantitative milestone requirements set forth at Sec.
51.1013;
    (vii) Contingency measure requirements set forth at Sec.  51.1014;
and,
    (viii) Nonattainment new source review plan requirements pursuant
to section 189(b)(3) and section 172(c)(5) of the CAA.
    (2) The state(s) shall submit its Serious area attainment plan to
EPA according to the following schedule:
    (i) For any nonattainment area reclassified to Serious for a
particular PM2.5 NAAQS under Sec.  51.1002(b)(1), the
state(s) shall submit to EPA the portion of the Serious area attainment
plan that meets the requirements set forth at paragraphs (b)(1)(i),
(iii) and (viii) of this section no later than 18 months from the date
of reclassification. The state(s) shall submit to EPA the portion of
the Serious area attainment plan that meets the requirements set forth
at paragraphs (b)(1)(ii) and (b)(1)(iv) through (vii) of this section
to EPA no later than 4 years from the date of reclassification.
    (ii) For any nonattainment area reclassified to Serious for a
particular PM2.5 NAAQS under Sec.  51.1002(b)(2), the
state(s) shall submit to EPA a Serious area attainment plan meeting the
requirements set forth at paragraphs (b)(1)(i) through (viii) of this
section no later than 18 months from the date of reclassification.
    (iii) If the state(s) submits to EPA a request for a Serious area
attainment date extension simultaneous with the Serious area attainment
plan due under paragraph (b)(1) of this section, such a plan shall meet
the most stringent measure (MSM) requirements set forth at Sec.
51.1010(b) in addition to the BACM and BACT and additional feasible
measure requirements set forth at Sec.  51.1010(a).
    (c) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain the PM2.5 NAAQS by the applicable Serious
area attainment date.
    (1) For any Serious nonattainment area that fails to attain a
particular PM2.5 NAAQS by the applicable Serious area
attainment date, the state(s) shall submit a revised Serious area
attainment plan that demonstrates that the area annually will achieve
at least 5 percent reductions in emissions of direct PM2.5
and PM2.5 precursors based on the most recent emissions
inventory for the area and that meets the following requirements:
    (i) Emissions inventory requirements set forth at Sec.
51.1008(c)(1);
    (ii) Emissions inventory requirements set forth at Sec.
51.1008(c)(2);
    (iii) Demonstration of attainment and modeling requirements set
forth at Sec.  51.1011;
    (iv) Reasonable Further Progress (RFP) requirements set forth at
Sec.  51.1012;
    (v) Quantitative milestone requirements set forth at Sec.  51.1013;
and,
    (vi) Contingency measure requirements set forth at Sec.  51.1014.
    (2) The state(s) shall submit to EPA the revised attainment plan
meeting the requirements set forth at paragraphs (c)(1)(i) through (vi)
of this section no later than 12 months from the missed applicable
Serious area attainment date.
    (d) Any attainment plan submitted to EPA under this section shall
establish motor vehicle emissions budgets for the projected attainment
year for the area, if applicable. The state shall develop such budgets
according to the requirements of the transportation conformity rule as
they apply to PM2.5 nonattainment areas (40 CFR part 93).

Sec.  51.1004  Attainment dates.

    (a) The state shall submit a projected attainment date as part of
its attainment plan submission under Sec.  51.1003 for any
PM2.5 NAAQS nonattainment area located in whole or in part
within its boundaries. The state shall justify the projected attainment
date for each such nonattainment area (or portion of a nonattainment
area) as part of the demonstration of attainment developed and
submitted according to the requirements set forth at Sec.  51.1011 and
according to the following:
    (1) Nonattainment areas initially classified as Moderate.
    (i) Except for nonattainment areas that meet the criterion under
paragraph (a)(1)(ii) of this section, the projected attainment date for
a Moderate PM2.5 nonattainment area shall be as expeditious
as practicable with the implementation of all control measures required
under Sec.  51.1009 and may be as late as the end of the sixth calendar
year after the date of designation if the state demonstrates that the
implementation of certain control measures that qualify as RACM or RACT
or additional reasonable measures, but that are not necessary for
demonstrating attainment by the end of the sixth calendar year after
the date of designation, will not collectively advance the attainment
date by at least 1 year.
    (ii) The projected attainment date for a Moderate PM2.5
nonattainment area which the state demonstrates cannot practicably
attain the applicable PM2.5 NAAQS by the end of the sixth
calendar year after the date of designation of the area with the
implementation of all control measures required under Sec.  51.1009
shall be such date unless and until the area is reclassified as Serious
according to Sec.  51.1002.
    (2) Nonattainment areas reclassified to Serious.
    (i) Except for nonattainment areas that meet the criterion under
paragraph (a)(2)(ii) of this section, the projected attainment date for
a Serious PM2.5 nonattainment area shall be as expeditious
as practicable with the implementation of all control measures required
under Sec.  51.1010 but no later than the end of the tenth calendar
year after the date of designation.

[ALTERNATIVE PROPOSED REGULATORY TEXT]

    (i) Except for nonattainment areas that meet the criterion under
paragraph (a)(2)(ii) of this section, the projected attainment date for
a Serious PM2.5 nonattainment area shall be as

expeditious as practicable with the implementation of all control
measures required under Sec.  51.1010 and may be as late as the end of
the tenth calendar year after the date of designation if the state
demonstrates that the implementation of certain control measures that
qualify as BACM or BACT or additional feasible measures, but that are
not necessary for demonstrating attainment by the end of the tenth
calendar year after the date of designation, will not collectively
advance the attainment date by at least 1 year.]
    (ii) A state that submits an attainment plan that demonstrates that
a Serious PM2.5 nonattainment area cannot practicably attain
the PM2.5 NAAQS by the end of the tenth calendar year
following the date of designation of the area with the implementation
of all control measures required under Sec.  51.1010(a) must request an
extension of the Serious area attainment date consistent with Sec.
51.1005(b). The request must propose a projected attainment date for
the nonattainment area that is as expeditious as practicable, but no
later than the end of the fifteenth calendar year from the date of
designation of the area.
    (3) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain by the applicable Serious area attainment date. The
projected attainment date for a Serious PM2.5 nonattainment
area that failed to attain the PM2.5 NAAQS by the applicable
Serious area attainment date shall be as expeditious as practicable
based on annual reductions in direct PM2.5 and significant
PM2.5 precursor emissions within the area of not less than 5
percent of the amount of such emissions as reported in the most recent
emissions inventory prepared for the area, but no later than 5 years
following the missed Serious area attainment date.
    (b) Except for attainment plans that meet the conditions of
paragraphs (a)(1)(ii) or (a)(3) of this section, the Administrator
shall approve an attainment date at the same time and in the same
manner in which the Administrator approves the attainment plan for the
area.
    (1) In accordance with paragraph (a)(1)(ii) of this section, if a
state demonstrates that a Moderate PM2.5 nonattainment area
cannot practicably attain the PM2.5 NAAQS by the end of the
sixth calendar year following the date of designation of the area, EPA
shall proceed under the provisions of Sec.  51.1002(b)(1) to reclassify
the area to Serious through notice-and-comment rulemaking.
    (2) In accordance with paragraph (a)(3) of this section, if a
Serious PM2.5 nonattainment area fails to attain the
PM2.5 NAAQS by the applicable Serious area attainment date,
EPA will proceed to establish a new attainment date through a direct
final action published in the Federal Register.

Sec.  51.1005  Attainment date extensions.

    (a) Nonattainment areas initially classified as Moderate.
    (1) A state with a Moderate PM2.5 nonattainment area may
apply for a 1-year attainment date extension for the area if the
following conditions are met in the year preceding the applicable
attainment date for the area:
    (i) The state has complied with all requirements and commitments
pertaining to the area in the applicable implementation plan;
    (ii) For an area designated nonattainment for a particular 24-hour
PM2.5 NAAQS for which the state seeks an attainment date
extension, the 98th percentile concentration at each monitor in the
area for the calendar year prior to the applicable attainment date is
less than or equal to the level of the applicable 24-hour standard
(calculated according to the data analysis requirements in 40 CFR part
50, appendix N);
    (iii) For an area designated nonattainment for a particular annual
PM2.5 NAAQS for which the state seeks an attainment date
extension, the annual average concentration at each monitor in the area
for the calendar year prior to the applicable attainment date is less
than or equal to the level of the applicable annual standard
(calculated according to the data analysis requirements in 40 CFR part
50, appendix N).
    (2) The applicable implementation plan for a Moderate
PM2.5 nonattainment area for which a state seeks an
attainment date extension is the plan submitted to EPA to meet the
requirements of Sec.  51.1003(a).
    (3) For a Moderate PM2.5 nonattainment area, the
requesting state (or states) shall submit a written request by February
28 of the year following the applicable attainment date for the area.
    (4) A state with a Moderate area that received an initial 1-year
attainment date extension may apply for a second 1-year attainment date
extension for the area if the state meets the conditions described in
paragraph (a)(1) of this section in the year preceding the approved
attainment date.
    (b) Nonattainment areas reclassified as Serious.
    (1) A state may apply for one attainment date extension not to
exceed 5 years for a Serious nonattainment area if the following
conditions are met:
    (i) The state demonstrates that attainment of the applicable
PM2.5 NAAQS by the approved attainment date for the area
would be impracticable or, in the absence of an approved attainment
date, attainment of the applicable PM2.5 NAAQS by the
applicable statutory attainment date for the area would be
impracticable;
    (ii) The state has complied with all requirements and commitments
pertaining to the area in the applicable implementation plan; and,
    (iii) The state demonstrates that the attainment plan for the area
includes the most stringent measures (MSM) that are included in the
attainment plan of any state or are achieved in practice in any state,
and can feasibly be implemented in the area consistent with Sec.
51.1010(b).
    (2) At the time of application for an attainment date extension,
the state shall submit to EPA a Serious area attainment plan that meets
the following requirements:
    (i) Emissions inventory requirements set forth at Sec.  51.1008(b);
    (ii) Most stringent measures (MSM) requirement described under
paragraph (b)(1)(iii) of this section and Sec.  51.1010(b);
    (iii) Attainment demonstration and modeling requirements set forth
at Sec.  51.1011 that justify the state's conclusion under paragraph
(b)(1)(i) of this section;
    (iv) Reasonable Further Progress (RFP) requirements set forth at
Sec.  51.1012;
    (v) Quantitative milestone requirements set forth at Sec.  51.1013;
and,
    (vi) Contingency measure requirements set forth at Sec.  51.1014.
    (3) The applicable implementation plan for a Serious
PM2.5 nonattainment area for which a state seeks an
attainment date extension under Sec.  51.1004(a)(2)(ii) is the plan
submitted to EPA to meet the requirements set forth at Sec.
51.1003(a).
    (4) The applicable implementation plan for a Serious
PM2.5 nonattainment area for which a state seeks an
attainment date extension under Sec.  51.1004(a)(2)(i) is the plan
submitted to EPA to meet the requirements set forth at Sec.
51.1003(b)(1).
    (5) A state applying for an attainment date extension for a Serious
nonattainment area under Sec.  51.1004(a)(2)(ii) shall submit to EPA a
request for an extension at the same time as it submits the Serious
area attainment plan due under Sec.  51.1003(b)(1).
    (6) A state applying for an attainment date extension for a Serious
nonattainment area subsequent to submitting an initial Serious area
attainment plan that demonstrated

attainment of the NAAQS by the applicable attainment date consistent
with Sec.  51.1004(a)(2)(i) at the time of submittal may apply for such
an extension no later than 60 calendar days prior to the approved
attainment date for the area or, in the absence of an approved
attainment date, no later than 60 calendar days prior to the applicable
statutory attainment date for the area.
    (c) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain by the applicable Serious area attainment date. If a
Serious area fails to attain a particular PM2.5 NAAQS by the
applicable Serious area attainment date, the area is then subject to
the requirements of section 189(d) of the Act, and, for this reason,
the state is prohibited from requesting an extension of the applicable
Serious area attainment date for such area.
    (d) For any attainment date extension request submitted pursuant to
this section, the requesting state (or states) shall submit a written
request and evidence of compliance with these regulations which
includes both of the following:
    (i) Evidence that all control measures submitted in the applicable
attainment plan have been implemented, and
    (ii) Evidence that the area has made emission reduction progress
that represents reasonable further progress toward timely attainment of
the applicable PM2.5 NAAQS.
    (e) For a PM2.5 nonattainment area located in two or
more states or jurisdictions, all states and/or jurisdictions in which
such area is located shall submit separate attainment date extension
requests for the area consistent with the requirements set forth at
paragraph (d) of this section.

Sec.  51.1006  Requirements for demonstrating insignificant
contribution of PM2.5 precursors.

    (a) For purposes of determining that a particular PM2.5
precursor does not contribute significantly to ambient PM2.5
concentrations in a PM2.5 nonattainment area, the state
shall conduct a technical analysis that accounts for all emissions of
such PM2.5 precursor from all sources located within the
area.
    (b) The state shall submit results and supporting documentation for
any technical analyses conducted pursuant to paragraph (a) of this
section as part of any attainment plan for the area.

Sec.  51.1007  Requirements for de minimis source category
determinations for direct PM2.5 and PM2.5
precursors.

    (a) All categories of sources of direct PM2.5 emissions
and of emissions of PM2.5 precursors in a PM2.5
nonattainment area shall be considered non-de minimis unless and until
the state conducts a technical analysis to determine whether a
particular source category may qualify for a presumptive de minimis
source category exemption from evaluation for potential control
measures due to its minimal contribution to the ambient
PM2.5 concentrations in the area.
    (b) The state shall define source categories for stationary sources
classified under the North American Industry Classification System
(NAICS) at the level represented by four (4) digits or fewer.
    (c) The state shall define a single source category for on-road
mobile sources, including on-road vehicles and engines, and a single
source category for nonroad mobile sources, including nonroad engines,
equipment, and vehicles, or may define a single source category for all
mobile sources in the aggregate.

Sec.  51.1008  Emissions inventory requirements.

    (a) For any nonattainment area initially classified as Moderate,
the state shall submit to EPA all of the following:
    (1) A base year inventory for the nonattainment area for all
emissions sources that meets the following minimum criteria:
    (i) The inventory year shall be one of the 3 years used for
designations or another technically appropriate inventory year if
justified by the state in the plan submission.
    (ii) The inventory shall include actual emissions of all sources
within the nonattainment area.
    (iii) The emissions values shall be either annual total emissions
or average-season-day emissions. The state shall include as part of the
plan a rationale for providing annual or seasonal emissions.
    (iv) The inventory shall include direct PM2.5 emissions
and emissions of all PM2.5 precursors.
    (v) The state shall report emissions as point sources according to
the point source emissions thresholds of the Air Emissions Reporting
Rule (AERR), 40 CFR part 51, subpart A.
    (vi) The detail of the emissions inventory shall be consistent with
the data elements required by 40 CFR part 51, subpart A.
    (2) An attainment projected inventory for the nonattainment area
that meets the following minimum criteria:
    (i) The year of the projected inventory shall be the most
expeditious year for which attainment is demonstrated by the modeled
attainment plan.
    (ii) The emissions values shall be projected emissions of the same
sources included in the base year inventory for the nonattainment area
(i.e., those only within the nonattainment area). The state shall
include in this inventory projected emissions growth and contraction
from both controls and other causes during the relevant period.
    (iii) The temporal period of emissions shall be the same temporal
period (annual or average-season-day) as the base year inventory for
the nonattainment area.
    (iv) Consistent with the base year inventory for the nonattainment
area, the inventory shall include direct PM2.5 emissions and
emissions of all PM2.5 precursors.
    (v) The same sources reported as point sources in the base year
inventory for the nonattainment area shall be provided as point sources
in the attainment projected inventory for the nonattainment area.
Nonpoint and mobile source projected emissions shall be provided using
the same detail (e.g., state, county, and process codes) as the base
year inventory.
    (vi) The same detail of the emissions included shall be consistent
with the level of detail in the base year inventory (i.e., as required
by 40 CFR part 41, subpart A).
    (b) For any nonattainment area reclassified as Serious, the state
shall submit to EPA all of the following:
    (1) For purposes of meeting the emissions inventory requirements of
CAA section 172(c)(3), a base year inventory for the nonattainment area
for all emissions sources that meets the requirements listed under
paragraph (a)(1) of this section, and in addition, uses the Serious
area definition of a major source listed under Sec.
51.165(a)(1)(iv)(A)(vii) and (viii) in determining sources to include
as point sources.
    (2) An attainment projected inventory for the nonattainment area
that meets the criteria listed under paragraph (a)(2) of this section.
    (c) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain a PM2.5 NAAQS by the applicable Serious
area attainment date. No later than 12 months after EPA finds through
notice-and-comment rulemaking that a Serious nonattainment area, or
portion thereof contained within a state's borders, fails to attain a
PM2.5 NAAQS by the applicable attainment date and thus
becomes subject to the requirements under CAA section 189(d), the state
shall submit to EPA all of the following:
    (1) For purposes of meeting the emissions inventory requirements of

CAA section 172(c)(3), a base year inventory for the nonattainment area
for all emissions sources that meets the requirements listed under
paragraph (a)(1) of this section, and in addition, uses the Serious
area definition of a major source listed under Sec.
51.165(a)(1)(iv)(A)(vii) and (viii) in determining sources to include
as point sources.
    (2) An attainment projected inventory for the nonattainment area as
defined by Sec.  51.1000(e) and that meets the criteria listed under
paragraph (a)(2) of this section.

Sec.  51.1009  Moderate area attainment plan control strategy
requirements.

    (a) The state shall identify, adopt, and implement control
measures, including control technologies, on sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors located in any Moderate PM2.5 nonattainment area
or portion thereof located within the state consistent with the
following:
    (1) The state shall identify all sources of direct PM2.5
emissions and all sources of emissions of PM2.5 precursors
in the nonattainment area in accordance with the emissions inventory
requirements of Sec.  51.1008(a);
    (2) The state shall identify all potential control measures to
reduce emissions from all sources of direct PM2.5 emissions
and all sources of emissions of PM2.5 precursors in the
nonattainment area identified under paragraph (a)(1) of this section.
    (i) The state may elect not to identify potential control measures
to reduce emissions from any sources of a particular PM2.5
precursor if the state demonstrates that all sources of such
PM2.5 precursor contribute insignificantly to ambient
PM2.5 concentrations in the area under Sec.  51.1006.
    (ii) The state may elect not to identify potential control measures
to reduce emissions from sources in any source category of direct
PM2.5 emissions or emissions of PM2.5 precursors
determined to be a de minimis source category under Sec.  51.1007.
    (3) For any potential control measure identified under paragraph
(a)(2) of this section, the state may make a demonstration that such
measure is not technologically or economically feasible to implement in
whole or in part by the end of the sixth calendar year following the
date of designation of the area, and the state may eliminate such whole
or partial measure from further consideration under this paragraph.
    (i) For purposes of evaluating the technological feasibility of a
potential control measure, the state may consider factors including but
not limited to a source's processes and operating procedures, raw
materials, physical plant layout, and potential environmental impacts
such as increased water pollution, waste disposal, and energy
requirements.
    (ii) For purposes of evaluating the economic feasibility of a
potential control measure, the state may consider factors including but
not limited to capital costs, operating and maintenance costs, and cost
effectiveness of the measure.
    (iii) The state must submit to EPA as part of its Moderate area
attainment plan a detailed written justification for eliminating from
further consideration any potential control measure identified under
paragraph (a)(2) of this section on the basis of technological or
economic infeasibility.
    (4) The state shall use air quality modeling that meets the
requirements of Sec.  51.1011(a) and that accounts for emissions
reductions estimated due to all technologically and economically
feasible control measures identified for sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors in the Moderate PM2.5 nonattainment area to
demonstrate that the area can attain the applicable PM2.5
NAAQS as expeditiously as practicable but no later than the end of the
sixth year following the date of designation of the area, or to
demonstrate that the Moderate PM2.5 nonattainment area
cannot practicably attain the applicable PM2.5 NAAQS by such
date.
    (i) If the state demonstrates through air quality modeling that the
area can attain the applicable PM2.5 NAAQS by the end of the
sixth calendar year following the date of designation of the area, the
state shall adopt and implement all technologically and economically
feasible control measures identified under paragraph (a)(3) of this
section that are necessary to bring the area into attainment by such
date. The state shall also adopt and implement all other
technologically and economically feasible measures identified under
paragraph (a)(3) of this section that, when considered collectively,
would advance the attainment date for the area by at least 1 year.
    (A) Any control measure identified for adoption and implementation
under this paragraph that can be implemented in whole or in part by 4
years after the date of designation of the Moderate PM2.5
nonattainment area shall be considered RACM for the area. Any such
control measure that is also a control technology shall be considered
RACT for the area.
    (B) Any control measure identified for adoption and implementation
under this paragraph that can only be implemented in whole or in part
during the period beginning 4 years after the date of designation of
the Moderate PM2.5 nonattainment area and the beginning of
the calendar year containing the applicable attainment date for the
area shall be considered an additional reasonable measure for the area.
    (ii) If the state demonstrates through air quality modeling that
the area cannot practicably attain the applicable PM2.5
NAAQS by the end of the sixth calendar year following the date of
designation of the area, the state shall adopt all technologically and
economically feasible control measures identified under paragraph
(a)(3) of this section unless the state makes a demonstration that one
or more such measures, when considered collectively, would have minimal
effect on reducing ambient PM2.5 concentrations in the area.
    (A) Any control measure identified for adoption and implementation
under this paragraph that can be implemented in whole or in part by 4
years after the date of designation of the Moderate PM2.5
nonattainment area shall be considered RACM for the area. Any such
control measure that is also a control technology shall be considered
RACT for the area.
    (B) Any control measure identified for adoption and implementation
under this paragraph that can only be implemented in whole or in part
during the period beginning 4 years after the date of designation of
the Moderate PM2.5 nonattainment area through the end of the
sixth calendar year following the date of designation of the area shall
be considered an additional reasonable measure for the area.
    (b) The state shall identify, adopt, and implement control
measures, including control technologies, on sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors located outside the Moderate PM2.5 nonattainment