sampling technologies to characterize the precision of this approach.
In conjunction with our validation efforts, we intend to continue
participation in the ASTM D22 committee to develop and publish a
dilution sampling method and encourage other volunteers on that
committee to approve the consensus based dilution sampling method. We
believe that this work is nearly complete. As outlined above, we are
already undertaking laboratory studies to assess the method and to
identify possible modifications to reduce formation of these artifacts.
Preliminary laboratory evaluations conducted by EPA and by Environment
Canada\47\ indicate that additional artifact reductions of 60 to 90
percent may be achieved with other minor modifications to Method 202.
These preliminary findings indicate that Method 202 is essentially a
viable method that these proposed laboratory studies will serve to
enhance. Within 18 months we intend to propose, if necessary,
modifications to Method 202 or similar methodologies suitable for
measuring condensable PM2.5.
---------------------------------------------------------------------------

    \47\ ``Optimized Method 202 Sampling Train to Minimize the
Biases Associated with Method 202 Measurement of Condensable
Particulate Matter Emissions,'' John Richards, Tom Holder, and David
Goshaw, Air Control Techniques, P.C.; Air & Waste Management
Association, Hazardous Waste Combustion Specialty Conference AWM,
November 2-3, 2005, St. Louis, MO.
---------------------------------------------------------------------------

    As for CTM-040, we believe that further validation of this method
is unwarranted since the technology and procedures are based upon the
same as evaluated for promulgated Method 201A. Method 201A has
undergone public review and comment (55 FR 14246, April 17, 1990).
Also, as noted earlier, we have already begun laboratory and data
evaluation work the possible result of which would be a revised Method
202 to be proposed in the Federal Register to include improvements
indicated by the evaluation. At that same time, we may propose CTM-040
to be used in combination with Method 202 for measuring direct
PM2.5 with additional guidance on appropriate approaches to
testing for direct PM2.5 emissions from various types of
control measures (e.g., electrostatic precipitator and flue gas
desulphurization combinations).
3. Role of Condensable PM Emissions in Defining RACT
    Comment: Commenters indicated that States must reassess and revise
emissions limits if the States adopt methods for measuring direct
PM2.5 including condensable PM where not required
previously. Commenters noted that most existing PM emissions limits are
not reflective of data collected with

methods that measure condensable or filterable PM2.5 and,
therefore, not enforceable using a new or different test method.
    Response: We agree that coordinating the test method with the
pollutant defined by the emissions limit is critical to an effective
regulation. In the case of direct PM2.5 regulations, the
methods for measuring filterable and condensable PM provide data that
are significantly different than do methods often used in implementing
many current regulations (i.e., filterable plus condensable
PM2.5 versus filterable PM only). The existing PM emissions
regulations implementing many current SIPs have focused almost
exclusively on filterable PM at stack conditions or other elevated
temperatures (e.g., 250 [deg]F) with little or no measurement of
condensable PM, let alone filterable PM2.5. These
deficiencies exist in spite of the Agency's policies and guidance
presented in documents such as the 1987 PM10 SIP Development
Guideline \48\ and the General Preamble for the Implementation of Title
1 of the Clean Air Act Amendments of 1990 \49\ issued in 1992. These
documents set forth Agency policy stating that direct PM10
and direct PM2.5 emissions include both filterable and
condensable particulate matter. The policies are reinforced by a 2005
directive from the CAA Advisory Committee.\50\
---------------------------------------------------------------------------

    \48\ U.S. Environmental Protection Agency. PM-10 SIP Development
Guideline. Office of Air Quality Planning and Standards, Research
Triangle Park, NC. EPA Publication No. EPA-450/2-86-001. June 1987.
    \49\ The General Preamble is available online at http://www.epa.gov/ttn/oarpg/t1pfpr.html
.

    \50\ Clean Air Act Advisory Committee, Recommendations to the
Clean Air Act Advisory Committee--Phase I and Next Steps, Air
Quality Management Work Group, Environmental Protection Agency,
http://www.epa.gov/air/caaac/pdfs/report1-17-05.pdf, January 2005.

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    More to the point, the use of test methods that quantify only
filterable PM would limit the capability of any assessment of control
measures available for developing cost effective strategies to achieve
attainment of the PM2.5 NAAQS. Examples include an
attainment demonstration that includes control methodologies for PM
precursors which are likely to result in a significant decrease in the
emissions of direct PM2.5 (for example, alkaline scrubbers
to reduce SO2 emissions) and incorporate these direct
PM2.5 emissions reductions in their attainment demonstration
or allow for the use of these reductions as credits for other programs.
    Some States may decide to measure and control condensable PM
emissions prior to the end of the transition period. To the extent that
a State has the supporting technical information and test methods, the
State may also assess the capabilities of current control technologies,
possible modifications to such technologies, or new technologies as
appropriate relative to control of condensable PM2.5
emissions in developing effective control strategies and regulations.
As an example, a specific approach for controlling condensable PM could
be a change in control device operating temperature to achieve
necessary emissions reductions. We also note that it is important that
implementation of any new or revised rules and test methods should be
prospective and clearly differentiated from existing regulations to
avoid confusion over status of compliance relative to existing PM
emissions limits.
4. Sufficiency of Current Baselines Relative to Direct PM2.5
for Regulatory Development
    Comment: Many commenters indicated that the currently available
baselines for direct PM2.5 emissions are not sufficient for
States to develop effective emissions control regulations. One
commenter claimed that States will need additional information
regarding how to arrive at enforceable PM2.5 emissions
limitations through application of correlations to existing
PM10 emissions limitations.
    Response: We agree that State inventories accounting for direct
PM2.5 emissions are important to the NAAQS implementation
decision-making process. For example, the current national emissions
inventories have characterized the contribution of the condensable PM
emissions to range from 40 to 80 percent of the direct PM2.5
emissions particularly from combustion source categories. We also agree
in many cases, the emissions baselines are not sufficiently
representative of significant direct PM2.5 contributors to
allow States to develop effective and enforceable emissions limitations
for sources that may require control of direct filterable or
condensable PM2.5 emissions in order for States to come into
attainment with the PM2.5 NAAQS.
    We note that States are already required under the consolidated
emissions reporting rule (CERR) to report direct PM2.5
emissions, including condensable PM, in each inventory revision. That
means that inventories and associated baselines must address sources
and contributions of direct PM2.5 emissions, both filterable
and condensable PM, from individual sources and groups of sources as
well as for future year projected emissions. These data are important
for the purposes of calculating emissions reductions and demonstrating
that such reductions are attributable to the control measures being
implemented.
    In taking the process to the next step, we contend that many
current baselines established using the available direct filterable and
condensable PM2.5 national industry average emissions
factors (e.g., those found in AP-42 and WebFIRE, http://www.epa.gov/ttn/chief/efpac/index.html
) often are of quality insufficient to

establish effective source-specific emissions limits. First, national
industry average emissions factors are subject to significant
uncertainties as they usually represent data from a very limited number
of example facilities in a category and for a very limited number of
operating conditions. Second, the available emissions factors databases
may not include direct PM2.5 emissions data for specific
source types that appear in some State and local inventories.
    In short, we believe that States should rely on directly measured
emissions data in developing source category or pollutant-specific
emissions limits for regulations. This approach is preferable to the
use of these national industry average emissions factors such as those
found in AP-42. If there are no directly measured emissions data
available from the subject sources, national average emissions factors
should be used only with appropriate and significant adjustments for
uncertainty. Based on our initial study \51\ of the uncertainties
associated with national average emissions factors when applied to
site-specific or rule-development activities, we would expect
multipliers of 0.1 to 3.3 for an A-rated national average filterable
and condensable direct PM2.5 emissions factors. The level of
a particular multiplier would depend on how representative of the
source category the applicable emissions factor is, the quantity of
data supporting that emissions factor, and the specific application.
Determining what adjustment may apply for a particular application
requires detailed knowledge of the emissions control variability, the
expected range of operational and process variability, and the
statistical uncertainty in the measured emissions data. While more
general adjustments to emissions factors are possible for these
purposes, we believe that the better approach is to improve and update
the emissions factors used in the database for a particular area with
measured

direct PM2.5 emissions data. For these reasons and to allow
time for data collection and analysis, we have determined the need for
a period of transition for States in developing direct PM2.5
emissions reduction strategies.
---------------------------------------------------------------------------

    \51\ Option Paper 4--Providing Guidance Regarding The Use Of
Emissions Factors For Purposes Other Than Emissions Inventories,
September 2005, http://www.epa.gov/ttn/chief/efpac/projects.html.

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

5. Transition Period
    Comment: Some commenters suggested that EPA should allow States to
base their initial 2008 SIPs on NOX, SO2, and
filterable PM or PM10 (as a surrogate for filterable
PM2.5) rather than require State and local agencies to
develop direct PM2.5 emissions regulations immediately.
Commenters suggested that EPA provide a transition period for sources
to adopt SIPs that address direct PM2.5 and to apply the
appropriate test methods. The commenters proposed that during this
transition period, a source should be able to continue to use Method 5,
Method 17, or whatever method was used to set the underlying limit
contained in the source's title V operating permit. Commenters believe
that such a transition plan must provide additional time to collect
data related to condensable PM emissions. Commenters believe that this
additional time is necessary because it is unrealistic to develop SIP
revisions addressing condensable emissions by April 2008. Other
commenters suggested that source emissions inventories used for
regulatory decision-making and identifying regulatory control measures
must be based on accurate measurements.
    Response: As outlined above, we agree that a transition period
should be allowed to allow time to resolve and adopt appropriate
testing procedures for condensable PM emissions, to collect total
(filterable and condensable) PM2.5 emissions data that are
more representative of the sources in their areas, and develop
effective regulations for control of direct PM2.5, including
condensable PM.
6. Data Collection for Regulatory Development
    Comment: Several commenters recommended that EPA should be
responsible for developing data of emissions from common sources of
direct PM2.5.
    Response: We disagree with the commenters' recommendation that EPA
should be primarily or solely responsible for developing baseline data
on common sources of direct PM2.5 emissions. Commenters are
suggesting that we should collect data representative of direct
PM2.5 emissions from source categories potentially subject
to regulation of direct PM2.5 emissions. Furthermore, they
suggest that we expand or improve the current compilation of national
industry average emissions factors such as found in AP-42 and WebFIRE
(http://www.epa.gov/ttn/chief/efpac/index.html). Given the limited

extent to which national industry average emissions factors are
suitable for developing State or local regulations that set limits on
direct PM2.5 emissions, we believe that it is inherent that
States instead have primary responsibility for reviewing and applying
measured emissions data collected from their sources in enhancing their
current baselines. In some cases, this will mean that States and other
stakeholders will need to conduct more focused direct PM2.5
emissions data collection and improve relevant emissions factors.
    This approach is appropriate for several reasons. First, we believe
that stakeholders other than EPA are better equipped to identify
specific data needs and that they have the means to collect the data.
Second, we believe we are better positioned to provide guidance on test
planning, data collection, and emissions factors calculations with a
less direct role in data collection and evaluation. Third, we believe
that States in need of additional information can also benefit from
experience of other States with similar source types and who are
developing regulations to implement the NAAQS including the control of
condensable PM. See also the discussion in section II.L.2.c.1 above on
the currently active collaborative study to assess direct
PM2.5 emissions measurement technologies and to collect
updated direct PM2.5 emissions data.
7. Developing Effective Regulations for Direct PM2.5,
Including Condensable PM, Emissions
    Most current PM regulations focus on the control and measurement of
filterable PM emissions and do not account for condensable PM
emissions. At issue are assessing and accounting for the differences in
methodology and applicable limits when changing to a program designed
to achieve reductions in PM2.5 emissions, including
condensable PM.
    Comment: A number of respondents commented that EPA needs to
promulgate a PM2.5 test method and adopt regulatory language
that determines the PM2.5 limits based on that promulgated
PM2.5 test method as soon as possible. Other commenters
suggested that EPA and States have no choice but to revise the
underlying standard by adopting new monitoring requirements through a
notice and comment rulemaking. Further, these commenters indicate that
it is essential that EPA require that no change in a test method or in
methods of monitoring for determining compliance until such time as EPA
or the permitting agency have undertaken a notice and comment process
to determine how the emissions limitations must be revised. A number of
commenters cited specific components necessary for effective
regulations.
    Response: We agree that notice and comment rulemaking is
appropriate for establishing effective regulations. As noted above, we
are already undertaking a study of the available test methods to
determine the need for regulatory revisions. We also agree that new
regulations limiting direct PM2.5 emissions must include
effective emissions limitations to the extent that a State must reduce
sources of direct PM2.5. How a State determines to take such
regulatory action depends on the State's implementation plan. Regarding
the specific components necessary for effective regulations, see
section O below on enforcement and compliance issues.

M. Improving Source Monitoring

a. Background
    In the November 1, 2005 proposal, we discussed a number of actions
the EPA would undertake to improve the effectiveness of existing and
new regulations with improved source monitoring provisions.
Specifically, we repeated a plan outlined on January 22, 2004 (69 FR
3202; a Federal Register notice describing requirements for monitoring
in operating permits), that includes a four-part strategy for improving
monitoring of emissions at the source where necessary through
rulemaking. One element of that plan is for EPA to develop guidance on
how States can reduce PM2.5 emissions by improving source
monitoring related to PM2.5 emissions limits. We noted that
we expect to describe in such guidance methods of improving monitoring
frequency or adopting more appropriate monitoring for States to
consider in developing their PM2.5 SIPs and to illustrate
the amount of credit that States could receive in PM2.5 SIPs
for adopting such improved monitoring. We suggested that States with
areas where additional reductions are needed to help the area achieve
compliance with the NAAQS could implement improved monitoring measures
to obtain additional emissions reductions. We put forward that State
agencies could receive SIP credits as a result of enforceable improved
monitoring or

voluntary emissions monitoring programs meeting EPA voluntary program
policies.
    Specific examples of improved monitoring we outlined included: (1)
Conducting the currently required monitoring more frequently (i.e.,
increased monitoring frequency), (2) changing the monitoring technique
to a parameter more closely related to control of direct or precursor
PM2.5 emissions (i.e., a correlated parametric monitoring
technique), (3) changing the technique to more measurement of direct
PM2.5 emissions and PM2.5 precursors, or (4) a
combination of these improvements. These types of monitoring
improvements could be conducted for both controlled and uncontrolled
emissions units. The improved monitoring control measure would require
facilities to pay more attention to the operation of add-on air
pollution control devices, work practices, and other control measure
activities. The additional attention will reduce periods during which
control devices and other control measures do not operate as intended
or required. The result would be increased emissions reductions from
implementing existing and new rules.
    We discussed a range of currently applied and new monitoring
technologies. We addressed concerns we have about the limitations of
the widespread use of visual emissions (VE) monitoring techniques, such
as visible emissions checks, to show compliance with PM emissions
limits. We noted particular concerns about VE approaches, even with
frequent application, having the ability to verify compliance when the
margin of compliance is small or the ability to detect relatively
significant changes in emissions control performance. The other concern
we noted about the use of VE tools is the limited frequency at which
they are conducted. We cited studies on the availability of continuous
instrumental methods for monitoring opacity and operational parameters
closely related to PM control levels including the development of
repeatable correlations between parameter levels and PM emissions. We
noted that PM continuous emissions monitoring systems (PM CEMS)
technology provides the opportunity to quantify PM emissions levels
(concentration or emissions rates). These additional data provide the
source owner/operator with a level of information that can be useful
for understanding and operating the process and the control measures in
ways to minimize emissions, improve operating efficiencies, and reduce
enforcement liabilities. Furthermore, we noted that this technology
will provide the State with quantitative information on PM emissions
which will help improve the inventories and to implement effective
control strategies to meet the NAAQS.
    We also discussed at some length what we believe constitutes
improved monitoring and the potential for monitoring-related emissions
reductions. We discussed a study of how these emissions reductions
would be achieved by increasing the monitoring frequency or improving
the monitoring of an add-on air pollution control device or other
process activity above the level currently required in existing rules.
The increased frequency or improved technique would allow owners or
operators to achieve greater emissions reductions by identifying and
responding more quickly to periods of ineffective control measure
operation. States could use an improved monitoring control measure in
regulations or through other means to reduce emissions levels and
receive credits towards attainment. Specifically, we cited materials
that indicate that source owners and operators who increase monitoring
frequency could achieve emissions reductions up to 13 percent and those
who improve the monitoring technique could achieve emissions reductions
up to 15 percent. States with nonattainment areas in need of additional
reductions to achieve compliance with the NAAQS could implement an
improved monitoring measure and develop additional emissions reductions
credits. We outlined several specific examples.
    In order to inform our improved monitoring guidance development
efforts, we used the 2005 proposal to solicit specific comments on (1)
how potentially inadequate source monitoring in certain SIPs could be
improved; (2) how improved PM2.5 monitoring relates to title
V monitoring; (3) whether instrumental techniques are more appropriate
than visual emissions (VE) techniques for monitoring compliance with PM
emissions limits; and (4) a basis for determining whether improved
monitoring would be effective and under what conditions should be
required. We also requested comment on the feasibility of monitoring of
co-pollutant control measures and requested examples of improved
monitoring for any applications.
b. Final Rule
    We maintain that improved monitoring is critical to implementing
the PM2.5 direct and precursor emissions reductions
programs. We also believe that improving monitoring both in terms of
increasing data collection and analysis frequency and in measuring the
pollutant of interest more directly will accomplish several important
and advantageous outcomes. First, improved monitoring will improve
verification of compliance and assurance of the intended emissions
reductions. Second, improved monitoring can provide additional
emissions reductions through quicker detection and correction of
control measure problems. Third, improved monitoring can improve
operating efficiencies that often result in cost savings to the
facility exceeding the cost of the monitoring. We will continue to
evaluate the effects of improved monitoring on emissions reductions and
ways to quantify the benefits associated with improved monitoring.
    We intend to move forward with developing and providing additional
technical and informational materials regarding technologies
constituting improved monitoring and for developing regulations with
improved monitoring. These materials may also include guidance and
tools for establishing emissions reductions credits and the economic
benefits associated with improved monitoring. As noted in section L
above, we also reaffirm our policy that effective regulations must
include certain elements that define applicable emissions limitations,
the testing and monitoring requirements, and compliance, reporting, and
corrective action obligations.
c. Comments and Responses
    We expected to receive practical advice concerning improved
PM2.5 source emissions monitoring methods and field-tested
examples. Instead, commenters focused on (1) critiquing PM CEMS
technology (2) insisting that improving monitoring changes stringency
of existing rules and requires rulemaking, and (3) critiquing the
theoretical study linking emissions reductions with improved
monitoring.
1. Currently Available PM CEMS for Monitoring Direct PM2.5
Emissions
    Comment: Commenters noted that because currently available PM CEMS
measure filterable PM at stack conditions or at other elevated
temperatures, the instruments do not measure the condensable portion of
PM2.5.
    Response: We agree with this comment relative to PM CEMS in use to
date and the ability to detect condensable PM. PM CEMS as applied today
can be calibrated to measure filterable PM2.5 emissions with
very good sensitivity and repeatability. Note

that we are aware of a number of PM CEMS vendors developing devices
relying on much the same technology but modified to measure condensable
PM. Further, we are aware of at least one manufacturer offering a PM
CEMS applicable to stationary sources that also complies with ASTM
requirements for mobile source emissions monitoring. We also believe
that monitoring for filterable PM2.5 will be as important in
some cases as monitoring for condensable PM and that PM CEMS in use
today are markedly better at monitoring PM emissions than other
frequently used monitoring approaches.
    We realize that PM CEMS represent just one of a range of monitoring
options that constitute improvements over the current monitoring. For
instance, we believe that improved monitoring would include replacing
current periodic VE measurements or daily recording of pressure drop of
fabric filters with continuous bag leak detectors. We know of projects
(e.g., ASTM committee work) for continuing the development of optical,
as well as electromagnetic, monitoring tools to increase sensitivity
and cost-effectiveness. Such monitoring would increase monitoring
frequency and would yield data much more closely related to and more
sensitive to control device operation than most currently applied
monitoring. To the extent that condensable PM control is critical in
implementing a regulation, we believe that monitoring must address that
need. We will continue to collect and also provide information on
source monitoring approaches that are improvements over current methods
in both frequency and representativeness relative to implementing
PM2.5 emissions control strategies.
2. Status of Guidance Relative to Regulations
    Comment: A significant majority of commenters suggested that
improving monitoring in an existing regulation increases its stringency
and requires notice and comment rulemaking, not guidance. Just one
commenter suggested guidance could be developed and used.
    Response: There are two aspects to the comments on this issue. One
is whether improved monitoring would change source operations. We agree
with the commenters that increasing the frequency of data collection or
providing data more directly related to the pollutant of concern with
improved monitoring could result in changes in how a facility is
operated relative to compliance. We disagree with commenters that such
changes in process operation resulting from improved monitoring
constitute an increase in a regulation's stringency with respect to
compliance. First, as mentioned in the preamble to the Credible
Evidence rule (62 FR 8326, February 24, 1997), an emissions standard's
required stringency is unaffected by the frequency of monitoring given
no decrease in averaging time or emissions limitation. Secondly, data
from improved monitoring will provide a facility operator better
information on control measure performance more quickly and allow for
reducing the duration and the number of periods that may lead to
compliance problems. Reducing the duration of excess emissions periods,
for example, with improved monitoring is not an increase in regulatory
stringency but a decrease in enforcement liability.
    The second aspect to the comment is questioning whether we can
issue technical information about improved monitoring as guidance
without applying it to a Federal Register notice and comment process.
We disagree with commenters who believe that our developing and
disseminating technical resource information is limited to notice and
comment rulemaking. We note that making technical and other information
materials available to the public, states, and industry is an important
Agency function. There are many examples of the Agency dispensing such
information including the Monitoring Knowledge Base (http://cfpub.epa.gov/mkb/
) that provides just such information on improved

monitoring. On the other hand, we agree with commenters that any
significant change to an existing regulation, including the addition of
new monitoring requirements, would be subject to notice and comment
rulemaking. To the extent that States determine the need for changing
existing or developing new regulations, public notice and comment
rulemaking is appropriate. Our role in developing technical resources
and information informing the states in developing those revised or new
regulations does not require, nor should be subject to the rulemaking
process. In that light, we recognize the value in obtaining and
responding to public comments and suggestions on informative technical
materials. Further, we believe rulemaking is not necessarily required
for source owners or operators who volunteer to participate in an
optional improved monitoring program, such as the one mentioned in the
proposal. That program seeks to provide SIP credits to States where
source owners or operators agree to improve their PM monitoring
approaches. We plan on continuing to prepare and offer non-regulatory
incentives for source owners and operators who volunteer to improve
existing monitoring.
3. Study of Improved Monitoring-Induced Emissions Reductions
    Comment: Commenters recommended that the proposal's theoretical
study showing PM emissions reductions from the use of improved
monitoring needs to be validated with field data.
    Response: We agree with commenters that one should base any costs
and benefits findings as well as validating the approach on available
data. To the extent that this applies to assessing the benefits of
emissions reductions achieved through improved monitoring, we requested
that commenters provide data or leads to other information or to other
alternatives that show how improved monitoring yields emissions
reductions and ways to quantify possible PM credits for SIPs. In fact,
we are disappointed that commenters failed to provide these data or
examples of other approaches. As resources allow, we will investigate
opportunities for field validation of the theoretical study, as well as
other means to offer incentives for use of improved monitoring.

N. Guidance Specific to Tribes

a. Background
    The proposal set forth guidance for Tribes regarding various
aspects of air quality management, and this guidance remains largely
the same as described in the section below.
b. Final Rule
    The 1998 Tribal Authority Rule (TAR) (40 CFR part 49), which
implements section 301(d) of the CAA, gives Tribes the option of
developing tribal implementation plans (TIPs). Specifically, the TAR
provides for the Tribes to be treated in the same manner as a State in
implementing sections of the CAA. However, Tribes are not required to
develop implementation plans. The EPA determined in the TAR that it was
inappropriate to treat Tribes in a manner similar to a State with
regard to specific plan submittal and implementation deadlines for
NAAQS-related requirements, including, but not limited to, such
deadlines in CAA sections 110(a)(1), 172(a)(2), 182, 187, and 191. (Add
footnote) See 40 CFR 49.4(a). In addition, EPA determined it was not
appropriate to treat tribes similarly to states with respect to
provisions of the CAA requiring as a condition of program approval the
demonstration of criminal enforcement

authority or providing for the delegation of such criminal enforcement
authority. See 40 CFR 49.4(g). To the extent a tribe is precluded from
asserting criminal enforcement authority, the Federal government will
exercise primary criminal enforcement responsibility. See 40 CFR 49.8.
In such circumstances, tribes seeking approval for CAA programs provide
potential investigative leads to an appropriate federal enforcement
agency. (end footnote)
    If a Tribe elects to do a TIP, we will work with the Tribe to
develop an appropriate schedule which meets the needs of the Tribe, and
which does not interfere with the attainment of the NAAQS in other
jurisdictions. The Tribe developing a TIP can work with the EPA
Regional Office on the appropriateness of addressing RFP and other
substantive SIP requirements that may or may not be appropriate for the
Tribe's situation.
    The TAR indicates that EPA is ultimately responsible for
implementing CAA programs in Indian country, as necessary and
appropriate, if Tribes choose not to implement those provisions. For
example, an unhealthy air quality situation in Indian country may
require EPA to develop a FIP to reduce emissions from sources on the
reservation. In such a situation, EPA, in consultation with the Tribe
and in consideration of their needs, would work to ensure that the
NAAQS are met as expeditiously as practicable. Likewise, if we
determine that sources in Indian country could interfere with a larger
nonattainment area meeting the NAAQS by its attainment date, we would
develop a FIP for those sources in consultation with the Tribe, as
necessary or appropriate.
    The TAR also provides flexibility for the Tribe in the preparation
of a TIP to address the NAAQS. If a Tribe elects to develop a TIP, the
TAR offers flexibility to Tribes to identify and implement on a Tribe-
by-Tribe, case-by-case basis only those CAA programs or program
elements needed to address their specific air quality problems. In the
proposed Tribal rule, we described this flexible implementation
approach as a modular approach. Each Tribe may evaluate the particular
activities, including potential sources of air pollution within the
exterior boundaries of its reservation (or within non-reservation areas
for which it has demonstrated jurisdiction), which cause or contribute
to its air pollution problem. A Tribe may adopt measures for
controlling those sources of PM2.5-related emissions, as
long as the elements of the TIP are reasonably severable from the
package of elements that can be included in a whole TIP. A TIP must
include regulations designed to solve specific air quality problems for
which the Tribe is seeking EPA approval, as well as a demonstration
that the Tribal air agency has the authority from the Tribal government
to develop and run their program, the capability to enforce their
rules, and the resources to implement the program they adopt. In
addition, the Tribe must receive an eligibility determination from EPA
to be treated in the same manner as a State and to receive
authorization from EPA to run a CAA program.
    The EPA would review and approve, where appropriate, these partial
TIPs as one step of an overall air quality plan to attain the NAAQS. A
Tribe may step in later to add other elements to the plan, or EPA may
step in to fill gaps in the air quality plan as necessary or
appropriate. In approving a TIP, we would evaluate whether the plan
interferes with the overall air quality plan for an area when Tribal
lands are part of a multi-jurisdictional area. Because many of the
nonattainment areas will include multiple jurisdictions, and in some
cases both Tribal and State jurisdictions, it is important for the
Tribes and the States to work together to coordinate their planning
efforts. States need to incorporate Tribal emissions in their base
emission inventories if Indian country is part of an attainment or
nonattainment area. Tribes and States need to coordinate their planning
activities as appropriate to ensure that neither is adversely affecting
attainment of the NAAQS in the area as a whole.
c. Comments and Responses
    No public comments were received on this section.

O. Enforcement and Compliance

a. Background
    The proposed rule included a discussion of the specific
requirements that must be addressed in order for SIP regulations to be
enforceable.
b. Final Rule
    The final rule includes similar guidance on enforceable SIP
regulations, with some additional discussion about specific elements
that must be addressed regarding compliance testing and compliance
monitoring. (Note that enforceable SIP regulations may address these
key elements in different ways depending on the type of source category
being regulated.)
    In general, for a SIP regulation to be enforceable, it must clearly
spell out which sources or source types are subject to its requirements
and what its requirements (e.g., emission limits, work practices, etc.)
are. The regulation also needs to specify the time frames within which
these requirements must be met, and must definitively state
recordkeeping and monitoring requirements appropriate to the type of
sources being regulated. The recordkeeping and monitoring requirements
must be sufficient to enable the State or EPA to determine whether the
source is complying with the emission limit on a continuous basis. An
enforceable regulation must also contain test procedures in order to
determine whether sources are in compliance.
    Complete and effective regulations that ensure compliance with an
applicable emissions limit must include requirements for both
performance testing of emissions and ongoing monitoring of the
compliance performance of control measures. SIP regulations must
include the following critical elements of regulatory compliance
testing:
     Indicator(s) of compliance--the pollutant or pollutants of
interest (e.g., filterable PM2.5 plus condensable
PM2.5) and the applicable measurable units for expressing
compliance (e.g., ng/J of heat input, lb/hr);
     Test method--reference to a specific EPA or other
published set of sample collection and analytical procedures, equipment
design and performance criteria, and the calculations providing data in
units of the indicator of compliance (see section II.L. below for
descriptions of available and potential improved test methods);
     Averaging time--the minimum length of each required test
run and the requirement to average the results of the test runs (e.g.,
three runs) representing a specified period of time (e.g., 8 hours);
and
     Frequency--the maximum time between conduct of emissions
or performance tests (e.g., within 30 days of facility start-up and
once each successive quarter, every 6-month period, yearly).
    In order to be complete with regard to compliance monitoring
provisions, SIP regulations must include the following critical
elements:
     Indicator(s) of performance--the parameter or parameters
measured or observed for demonstrating proper operation of the
pollution control measures or compliance with the applicable emissions
limitation or standard. Indicators of performance may include direct or
predicted emissions measurements, process or control device (and
capture system) operational

parametric values that correspond to compliance with efficiency or
emissions limits, and recorded findings of verification of work
practice activities, raw material or fuels pollutant content, or design
characteristics. Indicators may be expressed as a single maximum or
minimum value, a function of process variables (e.g., within a range of
pressure drops), a particular operational or work practice status
(e.g., a damper position, completion of a waste recovery task), raw
material or fuel pollutant content, or an interdependency between two
or more variables;
     Measurement technique--the means used to gather and record
information of or about the indicators of performance. The components
of the measurement technique include the detector type or analytical
method, location and installation specifications, inspection
procedures, and quality assurance and quality control measures.
Examples of measurement approaches include continuous emissions
monitoring systems, continuous opacity monitoring systems, continuous
parametric monitoring systems, performance testing, vendor or
laboratory analytical data, and manual inspections and data collection
that include making records of process conditions, raw materials or
fuel specifications, or work practices;
     Monitoring frequency--the number of times to obtain and
record monitoring data over a specified time interval. Examples of
monitoring frequencies include at least one data value every 15 minutes
for continuous emissions or parametric monitoring systems, at least
every 10 seconds for continuous opacity monitoring systems, upon
receipt or application of raw materials or fuel to the process, and at
least once per operating day (or week, month, etc.) for performance
testing, work practice verification, or equipment design inspections;
and
     Averaging time--the period over which to average and use
data to verify compliance with the emissions limitation or standard or
proper operation of the pollution control measure. Examples of
averaging time include a 3-hour average in units of the emissions
limitation, a 30-day rolling average emissions value, a daily average
of a control device operational parametric range, periodic (e.g.,
monthly, annual) average of raw materials or fuel pollutant content,
and an instantaneous alarm.
    These regulatory elements are essential for effective
implementation of the rules and clear and enforceable applicable
requirements. We believe that approval of regulations implementing the
SIPs must ensure that these critical elements are present and clearly
defined to be approvable. We reiterate that the compliance obligations,
including emissions limits and other applicable requirements, must be
representative of and accountable to the assumptions used in the SIP
demonstration. This accountability includes the ability to transfer the
applicable regulatory requirements to an operating permit subject to
EPA and public review.
    Under the Title V regulations, sources have an obligation to
include in their Title V permit applications all emissions for which
the source is major and all emissions of regulated air pollutants. The
definition of regulated air pollutant in 40 CFR 70.2 includes any
pollutant for which a NAAQS has been promulgated, which would include
both PM10 and PM2.5. To date, some permitted
entities have been using PM10 emissions as a surrogate for
PM2.5 emissions. Upon promulgation of this rule, EPA will no
longer accept the use of PM10 as a surrogate for
PM2.5. Thus, sources will be required to include their
PM2.5 emissions in their Title V permit applications, in any
corrections or supplements to these applications, and in applications
submitted upon modification and renewal.\52\ The degree of
quantification of PM2.5 emissions required will depend on
the types of determinations that a permitting authority needs to
address for a particular source, the requirements of title V, and the
informational needs and requirements of the particular State in
question. Sources must continue to describe their PM10
emissions in their applications as indicated above because the original
PM10 NAAQS remains in effect.
---------------------------------------------------------------------------

    \52\ See 40 CFR 70.5(c)(3)(i), 70.5(b), and 70.7(a)(1)(i); 40
CFR 71.5(c)(3)(i), 71.5(b), and 71.7(a)(1)(i).
---------------------------------------------------------------------------

c. Comments and Responses
    Comment: One commenter disagreed with language in the preamble to
the proposal regarding Title V permitting requirements and the
requirement to include various emissions information in title V permit
applications. As described in 40 CFR 70.5(c)(3)(i) and 71.5(c)(3)(i),
sources are required to include in their permit applications all
emissions for which the source is major and all emissions of regulated
air pollutants. In the preamble to the proposal, the EPA stated that in
the past some permitted entities have been using PM10
emissions as a surrogate for PM2.5 emissions in permit
applications, or in corrections or supplements to applications. The EPA
stated that upon promulgation of this rule, the EPA will no longer
accept the use of PM10 as a surrogate for PM2.5.
    The commenter disagreed with language in the proposal stating that
sources would be required to detail or quantify PM2.5
emissions in permit applications, or in corrections or supplements to
applications. The commenter asserts that the inclusion of
PM2.5 emissions information is required in a Title V permit
application only if there is an applicable requirement in existence for
which the source's applicability is in question and cited to various
examples from the memorandum entitled ``White Paper for Streamlined
Development of Part 70 Permit Applications,'' from Lydia N. Wegman,
Deputy Director, Office of Air Quality Planning and Standards, to Air
Division Directors, Regions I-X, dated July 10, 1995.
    Response: The commenter is concerned that as a result of this rule
all applications (including initial, modification, and renewal
applications) will need to include a quantification of PM2.5
emissions, and that a State will request that every source supplement
or correct any existing title V application in order to provide an
estimation of PM2.5 emissions at the source.
    The EPA is not implying that this is the case. The degree of
quantification of PM2.5 emissions required in an application
(including an initial, modification, or renewal application), or in a
correction or supplement to an existing application, depends on the
types of determinations that a permitting authority needs to address
for a particular source, the requirements of title V, and the
informational needs and requirements of the particular State in
question. For example, if a source which emits PM2.5
emissions has submitted a title V application, but a draft permit has
not yet been issued, then the source is required to submit information
relative to the quantification of its PM2.5 emissions if
such information is needed or requested and it has not previously
submitted such information. See 40 CFR 70.5(b) and 71.5(b).
    Circumstances necessitating the quantification of PM2.5
emissions and the submittal of this information include: (1)
Determining all of the pollutants for which a source is major; (2)
determining whether an applicable requirement or program applies, e.g.,
determining the applicability of a SIP requirement or a PSD or
nonattainment NSR program, etc.; or (3) determining what fees a source
owes a permitting

authority as a result of considering PM2.5 emissions.
    In all circumstances, however, a State may require that a source
quantify its PM2.5 emissions information in an application,
supplement, or correction, even if it is not needed for the particular
determination at issue. The State, for example, may choose to obtain
this information for air quality planning purposes, developing emission
inventories, or for other purposes related to its air quality
management goals. Requesting such emissions information is an option
for any title V permitting authority.
    The ``White Paper for Streamlined Development of Part 70 Permit
Applications,'' referenced by the commenter, was a confirmation of EPA
policy with respect to the fact that the specificity of emissions
quantification can vary significantly, depending on the circumstances
of a particular source. It is also important to note that this guidance
document is a statement regarding the range of discretion available to
permitting authorities in implementing the emissions quantification
requirement, not a restriction of that discretion to minimum practices.
Thus, States can implement this guidance document at their option,
either in part or in its entirety.
    In summary, the purpose of the statements made in the preamble to
the proposal was to notify sources that as of the promulgation of this
final rule, the EPA will no longer accept the use of PM10
emissions information as a surrogate for PM2.5 emissions
information \53\ given that both pollutants are regulated by a National
Ambient Air Quality Standard and therefore are considered regulated air
pollutants. See the definition of regulated air pollutant in 40 CFR
70.2 and 71.2.\54\ The degree of quantification of PM2.5
emissions now required in an application (including an initial,
modification, or renewal application), or provided in a correction or
supplement to an existing application, will depend on the types of
determinations that a permitting authority needs to address for a
particular source, the requirements of title V, and the informational
needs and requirements of the particular State in question.
---------------------------------------------------------------------------

    \53\ For background information on issues surrounding
implementation of the PM2.5 NAAQS, see the EPA memo
entitled ``Implementation of New Source Review Requirements in
PM2.5 Nonattainment Areas,'' from Stephen D. Page,
Director, Office of Air Quality Planning and Standards, to Regional
Air Directors, Regions I-X, dated April 5, 2005.
    \54\ For background information on regulated air pollutants, see
the EPA memo entitled ``Definition of Regulated Air Pollutant for
Purposes of Title V,'' from Lydia N. Wegman, Deputy Director, Office
of Air Quality Planning and Standards, to Air Division Directors,
Regions I-X, dated April 26, 1993.
---------------------------------------------------------------------------

P. Emergency Episodes

a. Background
    In the proposal, we noted that subpart H of 40 CFR part 51
specifies requirements for SIPs to address emergency air pollution
episodes and for preventing air pollutant levels from reaching levels
determined to cause significant harm to the health of persons. We noted
that we anticipate proposing a separate rulemaking in the future to
update portions of that rule.

The preamble to the proposal
b. Final Rule
    We have not yet proposed any rule revision related to emergency
episodes.
c. Comments and Responses
    We received no comments on this section of the proposal.

Q. Ambient Monitoring

a. Background
    Ambient air quality monitoring for PM2.5 plays an
important role in identifying areas violating the NAAQS, control
strategy development, and tracking progress to attainment. We indicated
in the proposal that States are required to monitor PM2.5
mass concentrations using Federal Reference Method devices to determine
compliance with the NAAQS.\55\ We did not propose any revisions to
current ambient monitoring requirements listed in 40 CFR part 58.
Currently, there are more than 1200 FRM monitors located across the
country. States will need to maintain monitors in designated
nonattainment areas in order to track progress toward attainment and
ultimately determine whether the area has attained the PM2.5
standards.
---------------------------------------------------------------------------

    \55\ The PM2.5 monitoring regulations are located at
40 CFR part 58.
---------------------------------------------------------------------------

    In addition to the FRM network, EPA and the States have also
deployed more than 250 speciation monitoring sites around the country
to sample for chemical composition of PM2.5. The data
provided from these speciation monitors are invaluable in identifying
contributing source categories and developing control strategies to
reach attainment. Source apportionment and other receptor modeling
techniques rely on the detailed data on species, ions, and other
compounds obtained from chemical analysis. Analyses of rural versus
urban sites to identify which PM2.5 components comprise the
``urban excess'' (urban minus rural levels) portion of PM2.5
mass also rely on data from speciation monitors. The EPA encourages
states to expand their data analysis efforts using the wealth of
information provided from the speciation monitoring network.
b. Final Rule
    There is no change from the proposal. We are not promulgating any
additional monitoring requirements as part of this rulemaking. Revised
monitoring regulations were issued in 2006 along with the revised PM
NAAQS.
c. Comments and Responses
    There were no comments on this section.

III. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under section 3(f)(1) of Executive Order (EO) 12866 (58 FR 51735,
October 4, 1993), this action is an ``economically significant
regulatory action.'' Implementation of the PM2.5 NAAQS is
likely to have an annual effect on the economy of $100 million or more.
Accordingly, EPA submitted this action to the Office of Management and
Budget (OMB) for review under EO 12866 and any changes made in response
to OMB recommendations have been documented in the docket for this
action. For clarity, we note that the estimated costs and benefits of
implementing the 1997 PM2.5 NAAQS are not created by this
rule, because the Clean Air Act requires state implementation of the
1997 PM2.5 standards (through state development of plans
with enforceable requirements for sources) on a statutory timetable
regardless of whether EPA issues this rule interpreting the statutory
requirements. The rule reflects the statutory requirements.
    As part of the ``Regulatory Impact Analysis for Particulate Matter
National Ambient Air Quality Standards (September 2006),'' EPA prepared
an assessment of the estimated costs and benefits associated with
attaining the 1997 PM2.5 NAAQS in 2015, incremental to
currently promulgated federal and state programs including for example
the Clean Air Interstate Rule, the Nonroad Diesel Rule, and other
programs. This analysis is included as Appendix A of the report and is
available in the docket for this action and on EPA's Web site at:
http://www.epa.gov/ttn/ecas/regdata/RIAs/Appendix%20A_2015%20Analysis.pdf.
 This illustrative

analysis finds that the estimated monetized benefits of attaining the
1997 standards in 2015 are between $43 billion and $97 billion
annually, and the estimated monetized costs are $6.7 billion annually.
The RIA states: ``Note that because this analysis was intended to
compare costs and benefits of attaining alternative standards by fixed
dates, it did not attempt to identify for each designated
PM2.5 area measures that may be needed to meet subpart 1
Clean Air Act requirements, such as reasonably available measures and
attainment as expeditiously as practicable. It is expected that
additional costs and benefits will begin to accrue in earlier years as
states comply with these requirements.'' (RIA, p. 1-4)

B. Paperwork Reduction Act

    The information collection requirements in this rule have been
submitted for approval to the Office of Management and Budget (OMB)
under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. In a separate
Federal Register notice published today, EPA is requesting comment on
the information collection requirements of this rule. The information
collection requirements are not enforceable until OMB approves them.
    The data collected from the State or local air agency respondents
will include the required SIP elements prescribed in CAA sections 110
and part D, subpart 1 of title I for Implementation plans and the
requirements in this Implementation Rule (40 CFR 51.1000-51.1012). The
PM2.5 SIP will contain rules and other requirements designed
to achieve the NAAQS by the deadlines established under the CAA, and it
also contains a demonstration that the State's requirements will in
fact result in attainment. The SIP must meet the requirements in
subpart 1 to adopt RACM, RACT, and provide for RFP toward attainment
for the period prior to the area's attainment date.
    The Agency anticipates additional administrative burden during the
3 year period of the ICR for State governments and the Agency of
630,000 hours and 69,300 hours, respectively. Fifty percent of the
hours are expended in the first year with the remainder evenly divided
between the second and third years of the ICR period. Tribes are not
required to conduct attainment demonstrations or submit the RFP, RACT,
or RACM requirements.
    The present value of the total additional costs for State
government respondents is estimated at $33.4 million for the 3 year
period. On an equivalent annual basis that is $12.7 million per year
during the 3 year period of the ICR. The present value of the Agency
administrative cost burden is estimated at $3.7 million dollars for the
3 year period. This is equivalent to an equal annual stream of costs of
$1.4 million per year during the three year period. Burden means the
total time, effort, or financial resources expended by persons to
generate, maintain, retain, or disclose or provide information to or
for a Federal agency. This includes the time needed to review
instructions; develop, acquire, install, and utilize technology and
systems for the purposes of collecting, validating, and verifying
information, processing and maintaining information, and disclosing and
providing information; adjust the existing ways to comply with any
previously applicable instructions and requirements; train personnel to
be able to respond to a collection of information; search data sources;
complete and review the collection of information; and transmit or
otherwise disclose the information.
    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 EPA's
regulations in 40 CFR are listed in 40 CFR part 9. When this ICR is
approved by OMB, the Agency will publish a technical amendment to 40
CFR part 9 in the Federal Register to display the OMB control number
for the approved information collection requirements contained in this
final rule.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that 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 final action on small
entities, small entity is defined as: (1) A small business as defined
by 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; or (3) a small organization that is any
not-for-profit enterprise that is independently owned and operated and
is not dominant in its field.
    After considering the economic impacts of this final rule on small
entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities and it is not
necessary to prepare a regulatory flexibility analysis in conjunction
with this final rule. The final rule governing SIPs will not directly
impose any requirements on small entities. Rather, this rule interprets
the obligations established in the CAA for States to submit
implementation plans in order to attain the PM2.5 NAAQS.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and Tribal
governments and the private sector. Under section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
1 year. Before promulgating an EPA rule for which a written statement
is needed, EPA is required by section 205 of the UMRA to identify and
consider a reasonable number of regulatory alternatives, and adopt the
least costly, most cost-effective or least burdensome alternative that
achieves the objectives of the rule. The provisions of section 205 do
not apply when they are inconsistent with applicable law. Moreover,
section 205 allows EPA to adopt an alternative other than the least
costly, most cost-effective or least burdensome alternative if the
Administrator publishes with the final rule an explanation why that
alternative was not adopted. Before EPA establishes any regulatory
requirements that may significantly or uniquely affect small
governments, including Tribal governments, it must have developed under
section 203 of the UMRA a small government agency plan. The plan must
provide for notifying potentially affected small governments, enabling
officials of affected small governments to have meaningful and timely
input in the development of EPA regulatory proposals with significant
Federal intergovernmental mandates, and informing, educating, and
advising small governments on compliance with the regulatory
requirements.
    This rule contains no Federal mandate that may result in
expenditures

of $100 million or more for State, local, and Tribal governments, in
the aggregate, or the private sector in any 1 year. The estimated
administrative burden hours and costs associated with implementing the
PM2.5 NAAQS are estimated in the ICR for this rule. The
estimated costs presented there for States totals $33.4 million for a
three-year period. Thus, this rule is not subject to the requirements
of section 202 and 205 of the UMRA. The EPA consulted with governmental
entities affected by this rule and has determined that this rule
contains no regulatory requirements that may significantly or uniquely
affect small governments, including Tribal governments.
    The CAA imposes the obligation for States to submit SIPs to
implement the PM2.5 NAAQS. In this rule, EPA is merely
providing an interpretation of those requirements. However, even if
this rule did establish an independent requirement for States to submit
SIPs, it is questionable whether a requirement to submit a SIP revision
would constitute a Federal mandate in any case. The obligation for a
State to submit a SIP that arises out of section 110 and section 172
(part D) of the CAA is not legally enforceable by a court of law, and
at most is a condition for continued receipt of highway funds.
Therefore, it is possible to view an action requiring such a submittal
as not creating any enforceable duty within the meaning of section
421(5)(9a)(I) of UMRA (2 U.S.C. 658(a)(I)). Even if it did, the duty
could be viewed as falling within the exception for a condition of
Federal assistance under section 421(5)(a)(i)(I) of UMRA (2 U.S.C.
658(5)(a)(i)(I)).

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have Federalism implications.''
``Policies that have Federalism implications'' is defined in the
Executive Order to include regulations that 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.''
    At the time of proposal, EPA concluded that the proposed rule would
not have any federalism implications. The EPA stated that the proposed
rule would 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 CAA establishes
the scheme whereby States take the lead in developing plans to meet the
NAAQS. This rule clarifies the statutory obligations of States in
implementing the PM2.5 NAAQS. However, EPA recognized that
States would have a substantial interest in this rule and any
corresponding revisions to associated SIP requirements.
    Therefore, in the spirit of Executive Order 13132, and consistent
with EPA policy to promote communications between EPA and State and
local governments, EPA held a number of calls with representatives of
State and local air pollution control agencies and hosted a public
hearing in Washington, DC in November 2005. The EPA considered the
comments from State and local governments in developing the final rule.
    EPA concludes that this final rule does not have federalism
implications, for the reasons proposed. The final rule will not modify
the relationship of the States and EPA for purposes of developing
programs to implement the NAAQS. As noted above in section D on UMRA,
this rule does not impose significant costs on State and local
governments. (EPA estimates the costs to States to implement the
PM2.5 NAAQS to be $33.4 million.) Thus, Executive Order
13132 does not apply to this rule.

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

    Executive Order 13175, entitled ``Consultation and Coordination
with Indian Tribal Governments'' (65 FR 67249, November 9, 2000),
requires EPA to develop an accountable process to ensure ``meaningful
and timely input by Tribal officials in the development of regulatory
policies that have Tribal implications.'' This final rule does not have
``Tribal implications'' as defined in Executive Order 13175. This rule
concerns the requirements for State and tribal implementation plans for
attaining the PM2.5 air quality standards. The CAA provides
for States to develop plans to regulate emissions of air pollutants
within their jurisdictions. The Tribal Air Rule (TAR) under the CAA
gives Tribes the opportunity to develop and implement CAA programs such
as programs to attain and maintain the PM2.5 NAAQS, but it
leaves to the discretion of the Tribe the decision of whether to
develop these programs and which programs, or appropriate elements of a
program, they will adopt.
    Although Executive Order 13175 does not apply to this rule, EPA did
reach out to Tribal leaders and environmental staff in developing this
rule. From 2001-2004, the EPA supported a National Designations
Workgroup to provide a forum for tribal professionals to give input to
the designations process. In 2006, EPA supported a national ``Tribal
Air call'' which provides an open forum for all Tribes to voice
concerns to EPA about the NAAQS implementation process, including the
PM2.5 NAAQS. In these meetings, EPA briefed call
participants and Tribal environmental professionals gave input as the
rule was under development. Furthermore, in December 2005, EPA sent
individualized letters to all federally recognized Tribes about the
proposal to give Tribal leaders the opportunity for consultation.
    This final rule does not have Tribal implications as defined by
Executive Order 13175. It does not have a substantial direct effect on
one or more Indian Tribes, since no Tribe has implemented a CAA program
to attain the PM2.5 NAAQS at this time. The EPA notes that
even if a Tribe were implementing such a plan at this time, while the
rule might have Tribal implications with respect to that Tribe, it
would not impose substantial direct costs upon it, nor would it preempt
Tribal law.
    Furthermore, this rule does 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 developing plans
to attain the NAAQS, and this rule does nothing to modify that
relationship. As this rule does not have Tribal implications, Executive
Order 13175 does not apply.

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

    EO 13045, ``Protection of Children from Environmental Health and
Safety Risks,'' (62 FR 19885, April 23, 1997) applies to any rule that
(1) Is determined to be ``economically significant'' as defined under
Executive Order 12866, and (2) concerns an environmental health or
safety risk that EPA has reason to believe may have disproportionate
effect on children. If the regulatory action meets both criteria, the
Agency must evaluate the environmental health or safety effects of the
planned rule on children, and explain why the planned regulation is
preferable to other potentially effective and reasonably feasible
alternatives considered by the Agency. This final

rule is subject to EO 13045 because it is economically significant as
defined in EO 12866, and we believe that the environmental health risk
addressed by this action may have a disproportionate effect on
children. This rule implements a previously promulgated health-based
Federal standard--the PM2.5 NAAQS \56\. The NAAQS constitute
uniform, national standards for PM pollution; these standards are
designed to protect public health with an adequate margin of safety, as
required by CAA section 109. However, the protection offered by these
standards may be especially important for children because children,
along with other sensitive population subgroups such as the elderly and
people with existing heart or lung disease, are potentially susceptible
to health effects resulting from PM exposure. Because children are
considered a potentially susceptible population, we have carefully
evaluated the environmental health effects of exposure to PM pollution
among children. These effects and the size of the population affected
are summarized in section 9.2.4 of the Criteria Document and section
3.5 of the Staff Paper.
---------------------------------------------------------------------------

    \56\ See 62 FR 38652-38760, National Ambient Air Quality
Standards for Particulate Matter, Final Rule; also 40 CFR part 50.
---------------------------------------------------------------------------

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

    This final rule is not a ``significant energy action'' as defined
in Executive Order 13211, ``Actions That Significantly Affect Energy
Supply, Distribution, or Use,'' (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. This rule is not a ``significant energy
action,'' because it does not establish requirements that directly
affect the general public and the public and private sectors, but,
rather, interprets the statutory requirements that apply to States in
preparing their SIPs. The SIPs themselves will likely establish
requirements that directly affect the general public, and the public
and private sectors.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer Advancement Act
of 1995 (``NTTAA''), Public Law No. 104-113, section 12(d) (15 U.S.C.
272 note) directs EPA to use voluntary consensus standards (VCS) 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 VCS bodies. The NTTAA directs EPA to provide Congress,
through OMB, explanations when the Agency decides not to use available
and applicable VCS.
    This final rulemaking does not involve technical standards.
Therefore, EPA is not considering the use of any VCS. The EPA will
encourage the States and Tribes to consider the use of such standards,
where appropriate, in the development of their implementation plans.

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

    EO 12898 (59 FR 7629 (Feb. 16, 1994) establishes Federal executive
policy on environmental justice. Its main provision directs Federal
agencies, to the greatest extent practicable and permitted by law, to
make environmental justice part of their mission by identifying and
addressing, as appropriate, disproportionately high and adverse human
health or environmental effects of their programs, policies and
activities on minority populations and low-income populations in the
United States.
    The EPA has determined that the final rule should not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations because it increases the
level of environmental protection for all affected populations without
having any disproportionately high and adverse human health or
environmental effects on any population, including any minority or low-
income population. The health and environmental risks associated with
fine particles were considered in the establishment of the
PM2.5 NAAQS. The level is designed to be protective with an
adequate margin of safety. This final rule provides a framework for
improving environmental quality and reducing health risks for areas
that may be designated nonattainment.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. The EPA will submit a report containing the rule and
other required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A Major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is a ``major rule'' as defined by 5 U.S.C.
804(2). This rule will be effective June 25, 2007.

L. Petitions for Judicial Review

    Under section 307(b)(1) of the Act, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the District of Columbia Circuit by June 25, 2007. Filing a petition
for reconsideration by the Administrator of this final rule does not
affect the finality of this rule for the purposes of judicial review
nor does it extend the time within which a petition for judicial review
may be filed, and shall not postpone the effectiveness of such rule or
action. This action may not be challenged later in proceedings to
enforce its requirements. See Act section 307(b)(2).

M. Judicial Review

    Under sections 307(d)(1)(E) and 307(d)(1)(V) of the CAA, the
Administrator determines that this action is subject to the provisions
of section 307(d). Section 307(d)(1)(V) provides that the provisions of
section 307(d) apply to ``such other actions as the Administrator may
determine.'' While the Administrator did not make this determination
earlier, the Administrator believes that all of the procedural
requirements, e.g., docketing, hearing and comment periods, of section
307(d) have been complied with during the course of this rulemaking.

IV. Statutory Authority

    The statutory authority for this action is provided by 42 U.S.C.
7401, 7408, 7410, 7501-7509a, and 7601(a)(1). This notice is also
subject to 307(d) of the CAA (42 U.S.C. 7407(d)).

List of Subjects in 40 CFR Part 51

    Administrative practice and procedure, Air pollution control,
Intergovernmental relations, Nitrogen dioxide, Ozone, Particulate
matter, Sulfur oxides, Transportation, Volatile organic compound.

    Dated: March 29, 2007.
Stephen L. Johnson,
Administrator.

0
For the reasons set out in the preamble, title 40, chapter I of the
Code

of Federal Regulations is amended as follows:
0
1. The authority citation for part 51 continues to read as follows:

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

0
2. A new Subpart Z is added 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 Submittal of State implementation plan.
51.1003 [Reserved]
51.1004 Attainment dates.
51.1005 One-year extensions of the attainment date.
51.1006 Redesignation to nonattainment following initial
designations for the PM2.5 NAAQS.
51.1007 Attainment demonstration and modeling requirements.
51.1008 Emission inventory requirements for the PM2.5
NAAQS.
51.1009 Reasonable further progress (RFP) requirements.
51.1010 Requirements for reasonably available control technology
(RACT) and reasonably available control measures (RACM).
51.1011 Requirements for mid-course review.
51.1012. Requirements for contingency measures.

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.
    Act means the Clean Air Act as codified at 42 U.S.C. 7401-7671q.
(2003).
    Attainment date means the date by which an area, under an approved
State implementation plan, is required to attain the PM2.5
NAAQS (based on the average of three consecutive years of ambient air
quality data).
    Baseline year inventory for the RFP plan is the emissions inventory
for the year also used as the base year for the attainment
demonstration.
    Benchmark RFP plan means the reasonable further progress plan that
requires generally linear emission reductions in pollutants from the
baseline emissions year through the milestone inventory year.
    Date of designation means the effective date of the
PM2.5 area designation 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 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 has been approved in the SIP and
that results in reductions in emissions of PM2.5 or
PM2.5 precursors in a nonattainment area.
    Full implementation inventory is the projected RFP emission
inventory for the year preceding the attainment date, representing a
level of emissions that demonstrates attainment.
    Milestone year inventory is the projected RFP emission inventory
for the applicable RFP milestone year (i.e. 2009 and, where applicable,
2012).
    PM2.5 NAAQS means the particulate matter national
ambient air quality standards (annual and 24-hour) codified at 40 CFR
50.7.
    PM2.5 design value for a nonattainment area is the
highest of the three-year average concentrations calculated for the
monitors in the area, in accordance with 40 CFR part 50, appendix N.
    PM2.5 attainment plan precursor means S02 and
those other PM2.5 precursors emitted by sources in the State
which the State must evaluate for emission reduction measures to be
included in its PM2.5 nonattainment area or maintenance area
plan.
    PM2.5 precursor means those air pollutants other than
PM2.5 direct emissions that contribute to the formation of
PM2.5. PM2.5 precursors include S02,
NOX, volatile organic compounds, and ammonia.
    Reasonable further progress (RFP) means the incremental emissions
reductions toward attainment required under sections 172(c)(2) and
171(1).
    Subpart 1 means the general attainment plan requirements found in
subpart 1 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  Submittal of State implementation plan.

    (a) For any area designated by EPA as nonattainment for the
PM2.5 NAAQS, the State must submit a State implementation
plan satisfying the requirements of section 172 of the Act and this
subpart to EPA by the date prescribed by EPA which will be no later
than 3 years from the date of designation.
    (b) The State must submit a plan consistent with the requirements
of section 110(a)(2) of the Act unless the State already has fulfilled
this obligation for the purposes of implementing the PM2.5
NAAQS.
    (c) Pollutants contributing to fine particle concentrations. The
State implementation plan must identify and evaluate sources of
PM2.5 direct emissions and PM2.5 attainment plan
precursors in accordance with Sec. Sec.  51.1009 and 51.1010. After
January 1, 2011, for purposes of establishing emissions limits under
51.1009 and 51.1010, States must establish such limits taking into
consideration the condensable fraction of direct PM2.5
emissions. Prior to this date, States are not prohibited from
establishing source emission limits that include the condensable
fraction of direct PM2.5.
    (1) The State must address sulfur dioxide as a PM2.5
attainment plan precursor and evaluate sources of SO2
emissions in the State for control measures.
    (2) The State must address NOX as a PM2.5
attainment plan precursor and evaluate sources of NOX
emissions in the State for control measures, unless the State and EPA
provide an appropriate technical demonstration for a specific area
showing that NOX emissions from sources in the State do not
significantly contribute to PM2.5 concentrations in the
nonattainment area.
    (3) The State is not required to address VOC as a PM2.5
attainment plan precursor and evaluate sources of VOC emissions in the
State for control measures, unless:
    (i) the State provides an appropriate technical demonstration for a
specific area showing that VOC emissions from sources in the State
significantly contribute to PM2.5 concentrations in the
nonattainment area, and such demonstration is approved by EPA; or
    (ii) The EPA provides such a technical demonstration.
    (4) The State is not required to address ammonia as a
PM2.5 attainment plan precursor and evaluate sources of
ammonia emissions from sources in the State for control measures,
unless:
    (i) The State provides an appropriate technical demonstration for a
specific area showing that ammonia emissions from sources in the State
significantly contribute to PM2.5 concentrations in the

nonattainment area, and such demonstration is approved by EPA; or
    (ii) The EPA provides such a technical demonstration.
    (5) The State must submit a demonstration to reverse any
presumption in this rule for a PM2.5 precursor with respect
to a particular nonattainment area, if the administrative record
related to development of its SIP shows that the presumption is not
technically justified for that area.

Sec.  51.1003  [Reserved]

Sec.  51.1004  Attainment dates.

    (a) Consistent with section 172(a)(2)(A) of the Act, the attainment
date for an area designated nonattainment for the PM2.5
NAAQS will be the date by which attainment can be achieved as
expeditiously as practicable, but no more than five years from the date
of designation. The Administrator may extend the attainment date to the
extent the Administrator determines appropriate, for a period no
greater than 10 years from the date of designation, considering the
severity of nonattainment and the availability and feasibility of
pollution control measures.
    (b) In the SIP submittal for each of its nonattainment areas, the
State must submit an attainment demonstration justifying its proposed
attainment date. For each nonattainment area, the Administrator will
approve an attainment date at the same time the Administrator approves
the attainment demonstration for the area, consistent with the
attainment date timing provision of section 172(a)(2)(A) and paragraph
(a) of this section.
    (c) Upon a determination by EPA that an area designated
nonattainment for the PM2.5 NAAQS has attained the standard,
the requirements for such area to submit attainment demonstrations and
associated reasonably available control measures, reasonable further
progress plans, contingency measures, and other planning SIPs related
to attainment of the PM2.5 NAAQS shall be suspended until
such time as: the area is redesignated to attainment, at which time the
requirements no longer apply; or EPA determines that the area has
violated the PM2.5 NAAQS, at which time the area is again
required to submit such plans.

Sec.  51.1005  One-year extensions of the attainment date.

    (a) Pursuant to section 172(a)(2)(C)(ii) of the Act, a State with
an area that fails to attain the PM2.5 NAAQS by its
attainment date may apply for an initial 1-year attainment date
extension if the State has complied with all requirements and
commitments pertaining to the area in the applicable implementation
plan, and:
    (1) For an area that violates the annual PM2.5 NAAQS as
of its attainment date, the annual average concentration for the most
recent year at each monitor is 15.0 [mu]g/m3 or less
(calculated according to the data analysis requirements in 40 CFR part
50, appendix N).
    (2) For an area that violates the 24-hour PM2.5 NAAQS as
of its attainment date, the 98th percentile concentration for the most
recent year at each monitor is 65 [mu]g/m3 or less
(calculated according to the data analysis requirements in 40 CFR part
50, appendix N).
    (b) An area that fails to attain the PM2.5 NAAQS after
receiving a 1-year attainment date extension may apply for a second 1-
year attainment date extension pursuant to section 172(a)(2)(C)(ii) if
the State has complied with all requirements and commitments pertaining
to the area in the applicable implementation plan, and:
    (1) For an area that violates the annual PM2.5 NAAQS as
of its attainment date, the two-year average of annual average
concentrations at each monitor, based on the first extension year and
the previous year, is 15.0 [mu]g/m3 or less (calculated
according to the data analysis requirements in 40 CFR part 50, appendix
N).
    (2) For an area that violates the 24-hour PM2.5 NAAQS as
of its attainment date, the two-year average of annual 98th percentile
concentrations at each monitor, based on the first extension year and
the previous year, is 65 [mu]g/m3 or less (calculated
according to the data analysis requirements in 40 CFR part 50, appendix
N).

Sec.  51.1006  Redesignation to nonattainment following initial
designations for the PM2.5 NAAQS.

    Any area that is initially designated ``attainment/unclassifiable''
for the PM2.5 NAAQS may be subsequently redesignated to
nonattainment if ambient air quality data in future years indicate that
such a redesignation is appropriate. For any such area that is
redesignated to nonattainment for the PM2.5 NAAQS, any
absolute, fixed date that is applicable in connection with the
requirements of this part is extended by a period of time equal to the
length of time between the effective date of the initial designation
for the PM2.5 NAAQS and the effective date of redesignation,
except as otherwise provided in this subpart.

Sec.  51.1007  Attainment demonstration and modeling requirements.

    (a) For any area designated as nonattainment for the
PM2.5 NAAQS, the State must submit an attainment
demonstration showing that the area will attain the annual and 24-hour
standards as expeditiously as practicable. The demonstration must meet
the requirements of Sec.  51.112 and Appendix W of this part and must
include inventory data, modeling results, and emission reduction
analyses on which the State has based its projected attainment date.
The attainment date justified by the demonstration must be consistent
with the requirements of Sec.  51.1004(a). The modeled strategies must
be consistent with requirements in Sec.  51.1009 for RFP and in Sec.
51.1010 for RACT and RACM. The attainment demonstration and supporting
air quality modeling should be consistent with EPA's PM2.5
modeling guidance.
    (b) Required time frame for obtaining emissions reductions. For
each nonattainment area, the State implementation plan must provide for
implementation of all control measures needed for attainment as
expeditiously as practicable, but no later than the beginning of the
year prior to the attainment date. Consistent with section 172(c)(1) of
the Act, the plan must provide for implementation of all RACM and RACT
as expeditiously as practicable. The plan also must include RFP
milestones in accordance with Sec.  51.1009, and control measures
needed to meet these milestones, as necessary.

Sec.  51.1008  Emission inventory requirements for the PM2.5 NAAQS.

    (a) For purposes of meeting the emission inventory requirements of
section 172(c)(3) of the Act for nonattainment areas, the State shall,
no later than three years after designation:
    (1) Submit to EPA Statewide emission inventories for direct
PM2.5 emissions and emissions of PM2.5
precursors. For purposes of defining the data elements for these
inventories, the PM2.5 and PM2.5 precursor-
relevant data element requirements under subpart A of this part shall
apply.
    (2) Submit any additional emission inventory information needed to
support an attainment demonstration and RFP plan ensuring expeditious
attainment of the annual and 24-hour PM2.5 standards.
    (b) For inventories required for submission under paragraph (a) of
this section, a baseline emission inventory is required for the
attainment demonstration required under Sec.  51.1007 and for meeting
RFP requirements

under Sec.  51.1009. As determined on the date of designation, the base
year for this inventory shall be the most recent calendar year for
which a complete inventory was required to be submitted to EPA pursuant
to subpart A of this part. The baseline emission inventory for calendar
year 2002 or other suitable year shall be used for attainment planning
and RFP plans for areas initially designated nonattainment for the
PM2.5 NAAQS in 2004-2005.

Sec.  51.1009  Reasonable further progress (RFP) requirements.

    (a) Consistent with section 172(c)(2) of the Act, State
implementation plans for areas designated nonattainment for the
PM2.5 NAAQS must demonstrate reasonable further progress as
provided in Sec.  51.1009(b) through (h).
    (b) If the State submits to EPA an attainment demonstration and
State implementation plan for an area which demonstrates that it will
attain the PM NAAQS within five years of the date of designation, the
State is not required to submit a separate RFP plan. Compliance with
the emission reduction measures in the attainment demonstration and
State implementation plan will meet the requirements for achieving
reasonable further progress for the area.
    (c) For any area for which the State submits to EPA an approvable
attainment demonstration and State implementation plan that
demonstrates the area needs an attainment date of more than five years
from the date of designation, the State also must submit an RFP plan.
The RFP plan must describe the control measures that provide for
meeting the reasonable further progress milestones for the area, the
timing of implementation of those measures, and the expected reductions
in emissions of direct PM2.5 and PM2.5 attainment
plan precursors. The RFP plan is due to EPA within three years of the
date of designation.
    (1) For any State that submits to EPA an approvable attainment
demonstration and State implementation plan justifying an attainment
date of more than five and less than nine years from the date of
designation, the RFP plan must include 2009 emissions milestones for
direct PM2.5 and PM2.5 attainment plan precursors
demonstrating that reasonable further progress will be achieved for the
2009 emissions year.
    (2) For any area that submits to EPA an approvable attainment
demonstration and State implementation plan justifying an attainment
date of nine or ten years from the date of designation, the RFP plan
must include 2009 and 2012 emissions milestones for direct
PM2.5 and PM2.5 attainment plan precursors
demonstrating that reasonable further progress will be achieved for the
2009 and 2012 emissions years.
    (d) The RFP plan must demonstrate that in each applicable milestone
year, emissions will be at a level consistent with generally linear
progress in reducing emissions between the base year and the attainment
year.
    (e) For a multi-State nonattainment area, the RFP plans for each
State represented in the nonattainment area must demonstrate RFP on the
basis of common multi-State inventories. The States within which the
area is located must provide a coordinated RFP plan. Each State in a
multi-State nonattainment area must ensure that the sources within its
boundaries comply with enforceable emission levels and other
requirements that in combination with the reductions planned in other
state(s) will provide for attainment as expeditiously as practicable
and demonstrate reasonable further progress.
    (f) In the benchmark RFP plan, the State must identify direct
PM2.5 emissions and PM2.5 attainment plan
precursors regulated under the PM2.5 attainment plan and
specify target emission reduction levels to be achieved during the
milestone years. In developing the benchmark RFP plan, the State must
develop emission inventory information for the geographic area included
in the plan and conduct the following calculations:
    (1) For direct PM2.5 emissions and each PM2.5
attainment plan precursor addressed in the attainment strategy, the
full implementation reduction is calculated by subtracting the full
implementation inventory from the baseline year inventory.
    (2) The ``milestone date fraction'' is the ratio of the number of
years from the baseline year to the milestone inventory year divided by
the number of years from the baseline year to the full implementation
year.
    (3) For direct PM2.5 emissions and each PM2.5
attainment plan precursor addressed in the attainment strategy, a
benchmark emission reduction is calculated by multiplying the full
implementation reduction by the milestone date fraction.
    (4) The benchmark emission level in the milestone year is
calculated for direct PM2.5 emissions and each
PM2.5 attainment plan precursor by subtracting the benchmark
emission reduction from the baseline year emission level. The benchmark
RFP plan is defined as a plan that achieves benchmark emission levels
for direct PM2.5 emissions and each PM2.5
attainment plan precursor addressed in the attainment strategy for the
area.
    (5) In comparing inventories between baseline and future years for
direct PM2.5 emissions and each PM2.5 attainment
plan precursor, the inventories must be derived from the same
geographic area. The plan must include emissions estimates for all
types of emitting sources and activities in the geographic area from
which the emission inventories for direct PM2.5 emissions
and each PM2.5 attainment plan precursor addressed in the
plan are derived.
    (6) For purposes of establishing motor vehicle emissions budgets
for transportation conformity purposes (as required in 40 CFR part 93)
for a PM2.5 nonattainment area, the State shall include in
its RFP submittal an inventory of on-road mobile source emissions in
the nonattainment area.
    (g) The RFP plan due three years after designation must demonstrate
that emissions for the milestone year are either:
    (1) At levels that are roughly equivalent to the benchmark emission
levels for direct PM2.5 emissions and each PM2.5
attainment plan precursor to be addressed in the plan; or
    (2) At levels included in an alternative scenario that is projected
to result in a generally equivalent improvement in air quality by the
milestone year as would be achieved under the benchmark RFP plan.
    (h) The equivalence of an alternative scenario to the corresponding
benchmark plan must be determined by comparing the expected air quality
changes of the two scenarios at the design value monitor location. This
comparison must use the information developed for the attainment plan
to assess the relationship between emissions reductions of the direct
PM2.5 emissions and each PM2.5 attainment plan
precursor addressed in the attainment strategy and the ambient air
quality improvement for the associated ambient species.

Sec.  51.1010  Requirements for reasonably available control technology
(RACT) and reasonably available control measures (RACM).

    (a) For each PM2.5 nonattainment area, the State shall
submit with the attainment demonstration a SIP revision demonstrating
that it has adopted all reasonably available control measures
(including RACT for stationary sources) necessary to demonstrate
attainment as expeditiously as practicable and to meet any RFP
requirements. The SIP revision shall contain the list of the potential
measures considered by the State, and

information and analysis sufficient to support the State's judgment
that it has adopted all RACM, including RACT.
    (b) In determining whether a particular emission reduction measure
or set of measures must be adopted as RACM under section 172(c)(1) of
the Act, the State must consider the cumulative impact of implementing
the available measures. Potential measures that are reasonably
available considering technical and economic feasibility must be
adopted as RACM if, considered collectively, they would advance the
attainment date by one year or more.

Sec.  51.1011  Requirements for mid-course review.

    (a) Any State that submits to EPA an approvable attainment plan for
a PM2.5 nonattainment area justifying an attainment date of
nine or ten years from the date of designation also must submit to EPA
a mid-course review six years from the date of designation.
    (b) The mid-course review for an area must include:
    (1) A review of emissions reductions and progress made in
implementing control measures to reduce emissions of direct
PM2.5 and PM2.5 attainment plan precursors
contributing to PM2.5 concentrations in the area;
    (2) An analysis of changes in ambient air quality data for the
area;
    (3) Revised air quality modeling analysis to demonstrate
attainment;
    (4) Any new or revised control measures adopted by the State, as
necessary to ensure attainment by the attainment date in the approved
SIP of the nonattainment area.

Sec.  51.1012  Requirement for contingency measures.

    Consistent with section 172(c)(9) of the Act, the State must submit
in each attainment plan specific contingency measures to be undertaken
if the area fails to make reasonable further progress, or fails to
attain the PM2.5 NAAQS by its attainment date. The
contingency measures must take effect without significant further
action by the State or EPA.

 [FR Doc. E7-6347 Filed 4-24-07; 8:45 am]

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