in the stringency of emission limitation. The use of a single
multiplier would result in unplanned and variable changes in the
stringency in the existing emission limitations. These changes may
create unintended consequences for the affected sources and result in
poorly understood and quantified estimates of the benefits.

4. The existing PM test methods and the emission limits based upon
these methods have been acceptable since 1971, why do they need to be
changed for PM2.5?
    Several changes have occurred over the last 30 years that have
gradually eroded the predictive capabilities of particulate matter
source test methods used in most SIPs to evaluate the sources
performance in controlling the pollutant measured by the ambient air
quality test method. In the 1970's and early 1980's, the ambient air
quality test method quantified the total particulate matter suspended
in the ambient air. At the beginning of this period, particulate matter
control measures were relatively poor. Additionally, most of
particulate matter control measures applied over the last 30 years have
focused on filterable particulate matter. While some control measures
for other air pollutants also resulted in collateral reductions in
condensable particulate and particulate precursor emissions, these
reductions were relatively small. As a result, the relative amount of
sulfates, nitrates and condensed organic matter in the ambient air
particulate matter was proportionally greater in the 1980's than it was
in the 1970's. The promulgation of the PM10 NAAQS in 1987
resulted in further reductions in filterable PM from sources, but there
were few non-attainment areas where control of the condensable
constituents of PM10 was required in order to achieve
attainment. As a result, stationary source control measures that
addressed only the filterable component of particulate matter were
generally adequate to achieve the PM10 NAAQS.
    With the promulgation of the PM2.5 NAAQS in 1997 and
associated ambient air quality monitoring, speciation analyses of
PM2.5 show that a substantial portion of PM2.5
consists of sulfates, nitrates and organic carbon. These constituents
are also a substantial portion of the condensable particulate matter
collected from stationary sources. With the increased application of
increasingly efficient filterable particulate matter control measures,
condensable emissions have become a larger percentage of overall
PM2.5 emissions for several stationary source categories.
    Based upon the particle size distribution presented in Table 1.1-6
of AP-42, about 29 percent of the total filterable particulate matter
is filterable PM2.5. As a result, about 78 percent of the
total PM2.5 emissions would be condensable PM.\112\ Since
filterable particulate matter emissions controls have improved since
1971 and since most sources achieve substantially lower emissions than
required by State and Federal emissions limitations, and condensable
emissions have generally not been significantly reduced, the
significance of the condensable emissions as a proportion of direct
PM2.5 emissions may be greater than indicated above. A test
method that measures total filterable particulate matter, commonly
including mostly particles larger than PM2.5 and yet
excluding condensable emissions, is a poor indicator of source
performance at reducing PM2.5 emissions.
---------------------------------------------------------------------------

    \112\ The significance of the condensable fraction of
PM2.5 is illustrated using the original supporting data
for the Subpart D NSPS cited previously. The promulgated standard
was reduced by 50% because about half the emissions were filterable
PM and the other half were condensable PM. However, only about 29
percent of the filterable particulate matter is filterable
PM2.5 (based upon the particle size distribution
presented in Table 1.1-6 of AP-42). Therefore, about 78 percent of
the total PM2.5 emissions would be condensable PM {Total
PM = 0.5 filterable + 0.5 condensable, Total PM2.5 = (0.5
filterable x .29) + 0.5 condensable = 0.645, condensable
PM2.5 = 0.5/0.645 = 78%{time} .
---------------------------------------------------------------------------

5. What methods are available for measuring PM size and condensable PM
from stationary sources?
    EPA has adopted one of several methods that are available for
classifying particulate matter by aerodynamic diameter. The method
adopted is based upon the use of centrifugal forces created in cyclones
to separate particulate matter into two aerodynamic size
classifications. The cyclone specified in EPA Method 201 and 201A
separates particulate matter with a nominal aerodynamic diameter
greater than 10 micrometers from the remaining particulate matter. The
addition of a second smaller cyclone following the EPA Method 201A
cyclone as is specified in EPA Method CTM 40 separates the particulate
matter that has an aerodynamic diameter greater than 2.5 micrometers
from the remaining particulate matter. A filter follows the final
cyclone of these particle sizing methods to collect the smaller
material. Under EPA's source test methods to separate PM based on
particle size, both of the cyclones and the filter are maintained at
the flue gas temperature. Therefore, any material that is in a vapor
state in the flue gas but would be condensed as a result of dilution
and cooling when released to the ambient air will not be measured by
these particle sizing methods.
    Vapors that would condense to form particulate matter in the
ambient air can be quantified by EPA Method 202. The EPA Method 202 is
intended for use in conjunction with a filterable particulate matter
test method such as Method 201A or CTM 40. Impingers containing cold
water are used by most methods to condense water vapor for determining
the flue gas moisture content. Besides condensing water vapor in the
flue gas, organic and inorganic chemical vapors are also condensed in
these impingers. In EPA Method 202, the organic and inorganic vapors
condensed in the impingers are separated with an organic solvent and
weighed after evaporating the water and organic solvent used for
separation.
    As recommended by the National Academy of Sciences, EPA and others
are developing dilution based source test methods for collecting and
analyzing PM2.5. Rather than condensing vapors in chilled
water, cool filtered dilution air condenses the vapors prior to
collection on filters. In the new method developed by EPA, particulate
matter is sized using the same cyclones used in CTM 40. However, the
in-stack filter used in CTM 40 is removed so that all of the
PM2.5 particulate matter is collected at near ambient
temperature on the filters.
6. Why is a new dilution-based test method being developed by EPA?
    The use of dilution-based particulate matter sampling offers
several advantages over the combination of EPA Method CTM 40 and Method
202. One advantage is that the vapors are condensed and chemical
reactions occur in a manner similar to when stack gas is released to
the atmosphere. As a result, the potential for particulate matter
formation that may occur in water but would not occur in air is
eliminated. Another advantage is that the potential for losing
particulate matter during the evaporation of the impinger water is
eliminated. With the use of multiple filter types, the use of dilution
sampling methods will allow for the speciation of the collected
PM2.5 by the same methods used for speciation of ambient air
particulate matter. Additionally, dilution-based methods allow for the
measurement of the particle size distribution of the particulate matter
smaller than 2.5 micrometers. This can be accomplished by modifying the
hardware of the sampling equipment to extend the residence time of the
sampled particulate matter. The extra residence time allows the
ultrafine particulate matter initially formed during vapor condensation
to grow toward its ultimate particle size distribution.

7. What types of sources should use the new dilution-based test method?
    The new dilution-based test method would be appropriate for most
sources. Sources with very complex flue gas characteristics (e.g.,
having several acidic and alkali gases with semi-volatile organic
matter) and those sources that want to generate a speciation profile
specific to their facility should use the new dilution test method.
Sources with very low PM2.5 emission concentrations and low
SO2 and NOX emission concentrations also may wish
to use the new dilution method. However, the more complex operation and
increased size of the equipment associated with the new method may
persuade some sources to use an alternative method. Sources where the
flue gas is near ambient temperature or where the sampled gas can be
cooled to near ambient temperature could use CTM 40 or its equivalent
to quantify PM2.5 emissions. Sources with less complex flue
gas characteristics may want to use CTM 40 combined with EPA Method
202.
8. What are the main features of the new test method?
    The main features of the new test method are in the areas of sample
extraction, particle sizing, sample flow rate measurement, dilution air
conditioning, dilution air flow rate measurement, sample mixing with
dilution air and sample filtration. An additional major feature, where
particulate speciation is desired, is the method of extracting an
aliquot of the diluted sample. Flue gas is extracted isokinetically at
a flow rate that produces particulate matter sizing at 10 and 2.5
micrometers by the two in-stack cyclones. The sampled flue gas and the
PM2.5 particulate matter is extracted from the stack prior
to dilution and cooling with ambient air that has been conditioned by
removing excess moisture and ambient particulate matter with a HEPA
filter. The objective of all the methods is to achieve complete mixing
prior to filtration and to minimize sample losses on the internal
surfaces of the hardware. The PM2.5 is removed from the
diluted sample gas by a Teflon filter. The PM2.5 deposited
on the internal surfaces of the hardware is quantitatively recovered
with acetone. Both the Teflon filter and the PM2.5 recovered
from the internal surfaces of the sampler are weighed. When speciation
of the PM2.5 is desired, aliquots of the diluted sample gas
are extracted for collection on filters. The ambient air speciation
criteria are followed with respect to the filter media used and
analytical finish of the three filters.
9. What is the schedule for finalization of the new test method?
    We have posted the dilution-based PM2.5 source test
method on the TTN web as ``Conditional Test Method 39'' and expect that
this method will provide the basis for a 40 CFR Part 51, Appendix M
method to be proposed at a later date. Beyond proposing the EPA-
developed dilution test method, we may identify the use of a source
test method developed by a national voluntary consensus standard
setting organization. Public Law 104-113, also known as the National
Technology Transfer and Advancement Act (NTTAA), requires that we use
technical standards that are developed or adopted by voluntary
consensus standards bodies as a means to carry out policy objectives
where appropriate. The law also requires us to consult with such bodies
when it is in the public interest to participate with them in the
development of technical standards. Recently, the ASTM Source and
Ambient Atmospheres Committee developed a PM2.5 source test
method similar to the method we have developed. We believe that it is
in the interest of the public and the Agency to participate in the ASTM
process of developing a PM2.5 source test method. While we
cannot predict when an ASTM standard will be available and whether it
will be a suitable test method for EPA to specify for use in SIPs, we
expect to make a decision on the final test method in the near future.
We are aware of two manufacturers which have commercially available
equipment meeting the specifications of CTM-39 and the draft ASTM
certification.
10. How will use of this new method affect an areas emissions inventory
and the emissions inventory for individual sources?
    We do not expect that particulate matter emissions inventories will
be significantly affected by the use of this new test method. The
stationary source emissions of PM2.5 are based upon existing
filterable particulate matter size distributions and filterable and
condensable particulate matter emission factors. The emission factor
information is supported by source test data similar to that available
from EPA Method CTM-40 and Method 202. However, it is unclear how the
use of the new dilution sampling method will affect the
PM2.5 emission inventory for any particular source category.
Source categories for which emission estimates for condensable
particulate matter are not available or are under estimated may find
that the inventoried emissions are significantly higher. As indicated
previously, the addition of the condensable portion of PM2.5
to filterable PM2.5 may increase direct PM2.5
emissions by a factor of five or more. Source categories for which the
condensable particulate matter emission factor is based on EPA Method
202 test data that excludes the nitrogen purge may find that their
emissions are somewhat lower. The significance of this lower mass of
condensable particulate matter depends on the mass of filterable and
condensable particulate matter compared to the mass of particulate
artifact formed by the dissolved SO2 that was not removed
from the impinger water by the nitrogen purge.
11. How will use of this new method affect a State's implementation
program more broadly?
    The use of this new dilution method (or the use of EPA Method CTM
40 combined with Method 202) to obtain measured source specific
emissions of PM2.5 will improve the quality of the emissions
inventory for stationary sources and will aid in the development of a
more reliable attainment strategy. In addition, we expect the use of
the speciation capabilities of this new source test method will expand
the information available to formulate attainment demonstration
strategies and to justify the most effective strategy. For example,
this new source-specific speciation data may allow the State to
identify additional local control measures for consideration. The
combined information from the ambient air speciation network and
individual source category speciation data will aid in developing the
most efficient attainment strategies. In addition, after initial
attainment strategies are implemented, speciation profiles for the most
significant sources of direct PM2.5 combined with data from
the ambient monitoring network may enable States to make important mid-
course revisions to attainment strategies as needed.

Q. How can potentially inadequate source monitoring in certain SIP
rules be improved?

1. How Does Improved PM2.5 Monitoring Relate to Title V
Monitoring?
    Two provisions of EPA's State and federal operating permits program
regulations require that title V permits contain monitoring
requirements. The ``periodic monitoring'' rules, 40 CFR
70.6(a)(3)(i)(B) and 71.6(a)(3)(i)(B), require that:

    ``[w]here the applicable requirement does not require periodic
testing or instrumental or noninstrumental monitoring (which may
consist of recordkeeping designed to serve as monitoring), [each
title V permit must contain] periodic monitoring sufficient to yield
reliable data from the relevant time period that are representative
of the source's compliance with the permit, as reported pursuant to
[Sec.  70.6(a)(3)(iii) or Sec.  71.6(a)(3)(iii)]. Such monitoring
requirements shall assure use of terms, test methods, units,
averaging periods, and other statistical conventions consistent with
the applicable requirement. Recordkeeping provisions may be
sufficient to meet the requirements of [Sec.  70.6(a)(3)(i)(B) and
Sec.  71.6(a)(3)(i)(B)].''

The ``umbrella monitoring'' rules, Sec. Sec.  70.6(c)(1) and
71.6(c)(1), require that each title V permit contain, ``[c]onsistent
with paragraph (a)(3) of this section, compliance certification,
testing, monitoring, reporting, and recordkeeping requirements
sufficient to assure compliance with the terms and conditions of the
permit.''
    In a final rule entitled ``Revisions to Clarify the Scope of
Certain Monitoring Requirements for Federal and State Operating Permits
Programs'' (69 FR 3202, January 22, 2004), EPA announced a four-step
strategy for improving existing monitoring where necessary through
rulemaking or other programmatic actions, while reducing resource-
intensive, case-by-case monitoring reviews and so-called ``gap-
filling'' in title V operating permits. Improved PM2.5
monitoring, as discussed in this preamble and to be addressed in future
guidance, is part of that strategy.
    In the first step, the ``umbrella monitoring'' rule (69 FR 3202,
January 22, 2004), EPA decided not to adopt proposed revisions to the
regulatory text of Sec. Sec.  70.6(c)(1) and 71.6(c)(1) (67 FR 58561,
September 17, 2002) and instead ratified the text of those rules
without making any changes. The EPA also announced that notwithstanding
the recitation in Sec. Sec.  70.6(c)(1) and 71.6(c)(1) of monitoring as
a permit element, EPA has determined that these provisions do not
establish a separate regulatory standard or basis for requiring or
authorizing review and enhancement of existing monitoring independent
of any review and enhancement as may be required under Sec. Sec.
70.6(a)(3) and 71.6(a)(3). The EPA explained that Sec. Sec.  70.6(c)(1)
and 71.6(c)(1) require that title V permits contain: (1) Monitoring
required by ``applicable requirements'' under the Act, as that term is
defined in Sec. Sec.  70.2 and 71.2 \113\; and (2) such monitoring as
may be required under Sec. Sec.  70.6(a)(3)(i)(B) and 71.6(a)(3)(i)(B).
See Appalachian Power Co. v. EPA, 208 F.3d 1015 (DC Cir. 2000). Thus,
for monitoring, EPA explained, Sec. Sec.  70.6(c)(1) and 71.6(c)(1)
constitute ``umbrella provisions'' that direct permitting authorities
to include monitoring required under existing statutory or regulatory
authorities in title V permits. Based on EPA's interpretation of the
Act, the plain language and structure of Sec. Sec.  70.6(c)(1) and
71.6(c)(1) and the policy reasons described in the preamble to the
umbrella monitoring rule (see 69 FR at 3204), EPA concluded that where
the periodic monitoring rules do not apply, Sec. Sec.  70.6(c)(1) and
71.6(c)(1) do not require or authorize a new and independent type of
monitoring in permits in order for the permits to contain monitoring to
assure compliance as required by the Act.
---------------------------------------------------------------------------

    \113\ The term ``applicable requirements'' includes, but is not
limited to: monitoring required under the compliance assurance
monitoring (CAM) rule, 40 CFR part 64, where it applies; monitoring
required under federal rules such as new source performance
standards (NSPS) in 40 CFR part 60, national emissions standards for
hazardous air pollutants (NESHAP) in 40 CFR part 61, maximum
achievable control technology (MACT) standards in 40 CFR part 63,
and the acid rain program rules in 40 CFR parts 72 through 75; and
monitoring required in EPA-approved SIP, TIP and FIP rules.
---------------------------------------------------------------------------

    In the ``umbrella monitoring'' rule, EPA also announced plans to
address monitoring in three related rulemaking actions. First, EPA
announced plans to encourage States to improve potentially inadequate
monitoring in certain SIP rules through this preamble and specifically
through separate guidance to be developed later in connection with this
rulemaking. The guidance is expected to describe 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. In particular, the guidance is
expected to address the widespread practice of using visual techniques,
such as visible emissions checks, to show compliance with particulate
matter limits. As discussed in section Q.2 below, we are concerned that
visible emissions techniques may be inadequate to detect
PM2.5 emissions in some circumstances. To the extent that
States implement this PM2.5 guidance and revise their SIPs
to adopt improved monitoring, then further actions by the State or EPA
to bring an area into attainment may be unnecessary.
    In addition, EPA announced plans to identify and consider improving
potentially inadequate monitoring in certain federal rules or in SIP
rules not addressed in connection with the PM2.5
implementation guidance or rulemaking over a longer time frame.
Specifically, EPA announced its intent to publish an advance notice of
proposed rulemaking requesting comment on what inadequate monitoring
may exist in federal applicable requirements and seeking suggestions as
to the ways in which inadequate monitoring in such rules could be
improved. EPA also announced its intent to request comment on
inadequate monitoring that may exist in other rules, such as SIP rules
not addressed in connection with this PM2.5 rulemaking and
guidance. The EPA indicated that comments received on the ANPR will
inform its decision as to what steps to take next, such as whether to
undertake national rulemakings to revise federal rules such as NSPS or
NESHAP. Finally, EPA announced plans to publish a separate proposed
rule to address what monitoring constitutes ``periodic'' monitoring
under Sec. Sec.  70.6(a)(3)(i)(B) and 71.6(a)(3)(i)(B) and what types
of monitoring should be created under Sec. Sec.  70.6(a)(3)(i)(B) and
71.6(a)(3)(i)(B). Together with the umbrella monitoring rule, these
three related rulemaking actions comprise EPA's four-step strategy for
improving existing monitoring where necessary on a programmatic basis.
2. Are Instrumental Techniques More Appropriate Than Visual Emissions
(VE) Techniques for Monitoring Compliance With PM Emissions Limits, for
Some Situations and Applications?
    We have a concern about the reliance on VE techniques (which are
based on observations of visible emissions or opacity) for monitoring
compliance with particulate matter emissions limits, in certain
situations. For example, in situations where a facility has a low
margin of compliance with its emission limit [e.g., the emission limit
is 25 milligrams of PM2.5 per dry standard cubic meter (mg/
dscm) and actual emissions are 22.5 mg/dscm, leaving a margin of
compliance of 2.5 mg/dscm], VE monitoring may not provide the level of
sensitivity necessary to monitor compliance. We also have a concern
about the infrequency of the monitoring sometimes associated with the
use of these VE monitoring techniques. Although visible emissions and
the opacity of visible emissions are indicators of a change in PM
emissions levels, we believe the use of available instrumental
monitoring technologies that provide a more direct measure of the
pollutant of concern, PM2.5, constitute improved monitoring
techniques and are the more appropriate

method in many cases. These instrumental techniques include bag leak
detectors (BLD), and particulate matter continuous emissions monitoring
systems (PM CEMS). In this proposal, we are encouraging States to adopt
improved monitoring techniques for PM2.5 in their SIPs, and
we plan to show, via separate guidance, how States can improve
emissions reductions and therefore increase credits in their SIPs if
they adopt the improved monitoring for selected sources. See the
discussion above in section I.17 for potential ways to obtain emissions
reductions through improved monitoring or controls. Note that the
improved monitoring techniques may also be appropriate for sources with
PM10 emissions.
    With respect to the frequency of VE monitoring, we believe more
frequent monitoring will reduce the potential for excess emissions to
occur unnoticed and, thus, will minimize the duration of excess
emissions periods. An example is the monitoring of VE from a fabric
filter control device utilizing weekly visual observations. The
potential exists for excess emissions to occur during the entire period
between observations, or up to seven days. Increasing the frequency of
observations to a daily basis significantly reduces the potential
duration of any excess emissions period. For example, consider an
emissions unit controlled with a fabric filter that emits 15 tons per
year PM2.5 (filterable), and has no visible emissions during
normal operation. For the baseline condition, assume an excess
emissions rate of 5 percent. By increasing the frequency of
observations from a weekly to a daily basis, the exceedences are
observed and corrective action and repair are taken in a more timely
manner; the resulting emissions reduction ranges from 11 to 13 tons per
year filterable PM2.5, or 37 to 81 percent reduction of the
potential excess emissions.\114\ If the potential emissions reduction
for filterable PM10 also is considered, the PM reductions
would include an additional 6.3 to 8.0 tons per year depending on the
calculation method used.
---------------------------------------------------------------------------

    \114\ ``Impact of Improved Monitoring on PM2.5
Emissions,'' memorandum from L. Barr and K. Schaffner, RTI
International, to B. Parker, U.S. Environmental Protection Agency.
December 2003.
---------------------------------------------------------------------------

    With respect to improved monitoring techniques for
PM2.5, we believe currently available instrumental
techniques are more capable of detecting changes in performance of the
control device than visual observations or COMS, in some applications,
such as at low emissions levels sometimes required for compliance with
PM2.5 emissions limits. Furthermore, unlike periodic visual
observations, these instrumental techniques provide information on a
continuous basis. Consequently, we believe use of these instrumental
techniques can reduce the occurrence of excess emissions because (1)
they are capable of sensing a change in performance that might not be
sensed by a visual technique and (2) when excess emissions occur, the
duration of excess emissions will be reduced as a result of the
frequency of monitoring. An example of an improved monitoring technique
is the use of a BLD to monitor PM2.5 emissions from a fabric
filter control device in lieu of weekly visual observations. Consider a
model emissions unit emitting 15 tons per year PM2.5
(filterable). For the baseline condition, assume an excess emissions
rate of 5 percent. By using a continuous instrumental technique, such
as a BLD, rather than weekly visual observations, the emissions from
potential excess emissions events would be reduced by 11 to 14 tons per
year of filterable PM2.5. If the potential emissions
reduction for filterable PM10 also is considered, the PM
reductions would be an additional 6.8 to 8.5 tons per year.\115\
---------------------------------------------------------------------------

    \115\ Ibid.
---------------------------------------------------------------------------

    Use of a PM CEMS is another improved monitoring technique. PM CEMS
technology provides the opportunity to quantitatively monitor PM
emissions levels (concentration or emissions rates). This provides the
source owner/operator with an additional level of information that can
be useful for understanding and operating the process and air pollution
control device. Furthermore, this technology will provide the State
with quantitative information on actual PM emissions, which will help
improve the inventory and achieve compliance with the NAAQS for
PM2.5.
    To inform our guidance development, we are asking for comment,
information, and relevant data on these monitoring issues.
Specifically:
    (1) In certain instances or applications, are we correct in our
belief that improved monitoring techniques are available and are more
appropriate to use than VE techniques for monitoring compliance with
PM2.5 emissions? Based on your experience, in which cases do
you believe improved monitoring techniques are more appropriate than VE
techniques for monitoring compliance with PM2.5 (or PM, in
general) emissions limits, and what monitoring techniques would you
recommend? Based on your experience, are BLD and PM CEMS reliable,
cost-effective methods that are more sensitive then VE techniques for
monitoring compliance with PM emissions?
    (2) Will increasing the frequency of VE observations resolve the
issue of applicability of VE techniques for monitoring compliance with
PM2.5 emissions? In other words, are there situations in
which increased VE frequency (i.e., daily versus weekly) would be
expected to have no impact on compliance with PM2.5 emission
limits? If so, please provide relevant data and explanation of such
situations.
    (3) Do we need to mandate through rulemaking a move away from VE
techniques for monitoring compliance with PM2.5 and PM
emissions limits, in certain situations and applications? If so, in
what cases?
    (4) Should our effort with regard to the use of improved monitoring
techniques in lieu of VE monitoring be focused on applicable
requirements established/relied upon for compliance with the
PM2.5 standard, or should we more broadly address other
applicable requirements where VE techniques are commonly used (e.g.,
TSP, PM10)?
    In addition, we also request comment, information, and relevant
data on any other issues relating to the use of VE techniques for
monitoring compliance with particulate matter emission limits.
3. What constitutes improved monitoring?
    Additional Reductions from Existing Rules. We request comment on
the following approach that States may choose to implement to reduce
emissions through the improved monitoring of emission controls at
stationary sources. An improved monitoring control measure would
increase emissions reduction for existing rules. These emissions
reductions would be achieved by increasing the monitoring frequency or
improving the monitoring technique of the add-on air pollution control
device operation and the process operation 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 correcting periods of excess emissions.
State, local, and Tribal agencies could use the improved monitoring
control measure option to reduce emission levels and receive credits.
As described in the docket, State, local, and Tribal air pollution
agencies who have source owners/operators increase monitoring frequency
at their facilities could achieve emissions reductions up to 13
percent, and those who improve the monitoring technique could achieve
emissions reductions up to 15

percent.\116\ Nonattainment areas where additional reductions are
needed to help the area achieve compliance with the NAAQS could
implement an improved monitoring measure. State, local, and Tribal air
pollution agencies could set a size cutoff or other criteria that would
define which facilities would be subject. State, local, and Tribal
agencies could receive SIP credits because enforceable improved
monitoring or voluntary programs meeting EPA's voluntary policies for
SIP credit could achieve additional emissions reductions for facilities
in the area.
---------------------------------------------------------------------------

    \116\ ``Impact of Improved Monitoring on PM2.5
Emissions,'' memorandum from L. Barr and K. Schaffner, RTI
International, to B. Parker, U.S. Environmental Protection Agency.
December 2003.
---------------------------------------------------------------------------

    Improved monitoring could come in the form of (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 PM2.5 and its precursors
(i.e., an improved monitoring technique), (3) changing the technique to
monitoring PM2.5 and its precursors, or (4) a combination of
these improvements. These types of monitoring improvements could be
conducted for both controlled and uncontrolled emission units. The
improved monitoring control measure would require facilities to pay
more attention to the operation of add-on air pollution control devices
and the process operation. The additional attention will reduce excess
emission periods and increase emissions reductions for existing rules.
    For the purposes of discussion today, we are focusing on two
scenarios. The first scenario involves increased monitoring frequency
for controlled emission units. The second scenario incorporates
improved monitoring techniques that include upgrading to a bag leak
detector (BLD) monitoring device and upgrading to a PM continuous
emissions monitoring system (CEMS) for controlled emission units.
    As an example of improved monitoring, consider a facility that
currently monitors for visible emissions once per day voluntarily
increasing its monitoring frequency of visible emissions to once per
hour, or installing a BLD system that continuously monitors the control
device. Under the improved monitoring control measure, the source
owners/operators would be more likely to detect the presence of a
problem and to correct it more quickly. Expedient detection and
correction of problems will result in reduced periods of excess
emissions and, consequently, lower emissions. The increased monitoring
frequency works to reduce the time between equipment failure and its
discovery by plant personnel. The underlying assumption is, of course,
that faster discovery leads to faster correction.
    The improved monitoring technique provides more certainty in
detecting the presence of a problem that may have gone unnoticed with
the previous technique. For example, consider a facility that monitors
opacity with a COMS as a surrogate for particulate matter. The
facility's opacity, as measured by the COMS, is consistently at 10
percent. However, emissions test data have shown that, when a new BLD
monitoring system is applied, the facility can be exceeding its PM
limit at an opacity less than 10 percent. In this example, application
of an improved monitoring technique provides a more direct and more
sensitive measurement of the pollutant of concern (PM vs. opacity) and
allows the facility to better track performance of the control device
and its emissions levels.
    In addition to the improved monitoring measures, there are other
ways to achieve significant PM2.5 emissions reductions,
including requiring add-on air pollution controls for uncontrolled
emissions units that are capable of being controlled. In this type of
approach, State, local, and Tribal agencies could require large
uncontrolled emission units to be controlled with new air pollution
control devices. Fabric filters would control filterable
PM2.5 emissions while other control devices such as
scrubbers would control both filterable and condensable
PM2.5 emissions. In one example for a large uncontrolled
unit, PM2.5 emissions (filterable) may be reduced by 131
tons per year when a fabric filter achieving 99 percent control
efficiency is installed. The cost effectiveness to install this new
control device would be determined based on the annualized cost of
operating the fabric filter and the emission reduction of
PM2.5 achieved by the device. If co-controlled pollutants
are included in the analysis, e.g., PM10 filterable
emissions, then the emissions reductions achieved by the new fabric
filter would include an additional 260 tons per year. The total
emission reduction for this source would be 390 tons per year; the
cost-effectiveness values with collateral benefits included will be
even lower. The fabric filter in this example would be monitored with a
BLD system on a continuous basis (at least four times per hour).
    What are the Assumptions Used to Determine the Reductions? We
estimated the emissions reductions that can be achieved by
implementation of the improved monitoring measures. Consistent with the
baseline excess emissions rate established in the compliance assurance
monitoring (CAM) rule (40 CFR part 64) analysis, we assumed an initial
excess emissions rate of five percent each year. Under the NSPS and
other federal rules, an excess emissions rate greater than five percent
is a trigger for increased reporting, and facilities generally ensure
that they do not exceed this threshold level of excess emissions to
avoid increased reporting. Of course, there may be exceptions to this
assumption, where facilities have excess emissions rates greater than 5
percent. The percentage of excess emissions represents a period of
noncompliance when emissions are likely to be above the allowable
emissions rates. Increased frequency monitoring will help owners or
operators of facilities to maintain the effectiveness of emissions
controls by identifying excursions early and repairing or adjusting the
control device immediately. The length of time that an emissions unit
is experiencing excess emissions is directly related to the level of
excess emissions from the source. Reducing the amount of time the
emission unit operates in this mode will reduce its actual emissions to
the atmosphere.
    In this study, we made two assumptions regarding the control
efficiency of the add-on air pollution control device during excess
emissions periods. In one method, we assumed the control device fails
catastrophically; that is, its control efficiency is zero percent. We
realize that some add-on air pollution control devices fail
catastrophically during malfunctions, while others operate at some
efficiency less than optimal but greater than zero. For the purposes of
the study and for simplification, we made the assumption of zero
percent control in this method. The control efficiency could also be
estimated at some value between zero and the design control efficiency.
In an alternative method, the control efficiency during excess
emissions periods was estimated to be 80 percent of the design
efficiency.
    The potential emissions reductions examined here mostly address
direct, filterable PM2.5 and also address condensable
PM2.5 only where the control device was likely to achieve
reductions for condensable emissions. Additional emissions reductions
may also be achieved for co-pollutants emitted from the emissions
units. We

believe that control for these other pollutants, e.g., PM10,
TSP, and HAP, may also be improved by the monitoring measures. However,
these improvements are not accounted for here. Improved monitoring,
i.e., increased frequency for existing monitoring instruments or
improved monitoring techniques, could also be applied to the precursors
of PM2.5 to achieve additional potential reductions.
    The improved monitoring control measure would increase emissions
reductions for existing rules. The emissions reduction achieved would
not necessarily be reflected in future emissions inventory data but
rather would be reflected in lower ambient air monitoring
concentrations.\117\ In assessing emissions from a particular facility,
we generally assume 100 percent compliance for 100 percent of the
operating time. However, excess emissions occur as a result of less
than full compliance with standards, rules, and regulations. For
example, a facility with an air pollution control device designed to
achieve a 95 percent control efficiency will achieve the design
efficiency if maintained and operated properly. Currently, the owner or
operator of such a facility would conduct a prescribed monitoring
technique (control device parameter, process parameter, or pollutant
concentration) at a prescribed frequency. Operation outside of limits
set for the monitored parameter(s) is an excursion for CAM rule
purposes (and may be an exceedance for other rules) and may be an
indication of excess emissions.
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    \117\ In the six metropolitan statistical areas reviewed for
this study, 100 percent rule effectiveness and 100 percent rule
penetration was shown in the 1999 NEI version 3 for all facilities.
---------------------------------------------------------------------------

    In accordance with CAM rule requirements, we assumed that
facilities are currently required to monitor add-on control devices of
applicable emission units at least once per day. With this approach, we
ensure that the emissions reductions achieved by the CAM rule are not
double-counted. We determined previously during the CAM rule
development that the detection of a problem with an add-on air
pollution control device that is monitored once per day could take up
to 12 hours to detect. After the problem has been detected, it may take
an additional 24 hours to conduct the repair, during which time the
process may be emitting above the emissions limit. The entire excess
emissions period could last up to 36 hours. By increasing the frequency
of monitoring and conducting diligent repair, the time required to
detect a problem will decrease, and the time a unit operates in excess
emission mode or malfunction will decrease.
    Examples of the Emissions Reductions that Can Be Achieved. In a
six-metropolitan statistical area (MSA) mini-study, we reviewed the
PM2.5 emissions data (filterable and some condensable) from
the 1999 NEI version 3 for all emission points at stationary sources
located in the MSAs. We applied the improved monitoring control
measures to only those emission points in the MSA that are controlled
with fabric filters, electrostatic precipitators, and scrubbers. This
subset included a total of 689 emission points at 128 facilities.
    Based on review of emission points with add-on air pollution
control devices, we found that PM2.5 emissions (filterable/
some condensable) can be reduced from 0.25 percent up to 13 percent
following the application of a requirement to conduct more frequent
monitoring. Potential PM2.5 emissions reductions ranged from
89 tons per year to 4,600 tons per year with increased monitoring
frequency. We also found that PM2.5 emissions (filterable/
some condensable) can be reduced from 2.5 percent to 15 percent by
requiring an improved monitoring technique such as a PM CEMS (and a
corollary increased frequency). The potential PM2.5
emissions reductions ranged from 810 to 5,300 tons per year. We
analyzed the emissions reductions achievable by reducing the excess
emission rate from the nominal 5 percent excess emissions to an excess
emissions rate of 2.5 percent (half of the nominal excess emission
rate), 0.46 percent (represents one week of excess emissions each year,
40 hours out of 8760), and 0 percent (no excess emissions). As
mentioned previously, there may be some facilities with an excess
emissions rate even greater than 5 percent; in these instances, the
potential emissions reductions due to improved monitoring may be even
greater. The emissions reduction calculation for application of an
improved monitoring control measure included a certainty factor related
to detecting excess emission periods and assurance of emissions levels.
The certainty factor for PM CEMS was 1.0, the factor for BLD was 0.95,
and the factor for parametric monitoring was 0.90. The certainty factor
for visual emissions and COMS when used to monitor PM was also 0.90.
    In another example of an improved monitoring technique, a BLD
monitoring system was applied only to the subset of emission units in
the six MSA area that are controlled with fabric filters. A total of
102 facilities were affected by this option. In this scenario, the
emission reduction (filterable PM2.5 only) was determined to
be 0.78 to 12 percent, or 280 to 4,100 tons per year.
    Costs to conduct monitoring at an increased frequency included the
cost to develop the more frequent monitoring approach and the
incremental annual costs for recordkeeping, reporting, and
certification related to the improved monitoring. Costs to implement an
improved monitoring technique included the total annual cost for the
new monitoring equipment, including the recordkeeping and reporting
costs associated with the new monitoring. We anticipate that changes to
monitoring would be incorporated into individual facility permits at
permit renewal, to help minimize costs to air agencies and source
owners/operators; costs related to incorporating the improved
monitoring into permits on a quicker basis than regular permit renewal
have not been assessed. The cost algorithms for the six-MSA study are
delineated in the ``Improved Monitoring'' memorandum. The cost-
effectiveness values include the emissions reductions for
PM2.5 filterable and some condensable. When reduction of co-
pollutants are included in the cost-effectiveness analysis, the cost-
effectiveness values are even lower. States can compare the cost
effectiveness for improved monitoring to the cost effectiveness of
other PM2.5 control measures when selecting the mix of
measures for their implementation plans.
    The methods for estimating emission reductions and cost
effectiveness ranges for the six-city study discussed in this section
are based on the best technical information we had available. We
recognize that commenters may have suggestions for ways to improve
these estimates. Thus, to inform our guidance development, we solicit
your comments on a number of issues. We solicit your comments on these
control measures for increased frequency of monitoring and improved
monitoring technique. We also request your comments on the feasibility
of co-pollutant control due to improved monitoring measures. We also
solicit submission of developed examples of improved monitoring,
including a description of the measure, monitoring data, etc., if
available. Finally, we encourage submission of methodologies--complete
with equations and explanations--for estimating emissions reductions
due to improved monitoring other than those referenced here.

R. What guidance should be provided that is specific to Tribes?

    This section summarizes guidance for Tribes offered in various
parts of this proposal. 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.\118\
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    \118\ 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.
---------------------------------------------------------------------------

    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.
    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.

S. Are there any additional requirements related to enforcement and
compliance?

    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 allow determinations on a continuing basis
whether sources are complying. An enforceable regulation must also
contain test procedures in order to determine whether sources are in
compliance.
    Under the Title V regulations, major 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.\119\ Sources must continue to
identify their PM10 emissions in their applications as
described above because the original PM10 NAAQS remains in
effect.
---------------------------------------------------------------------------

    \119\ 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).
---------------------------------------------------------------------------

T. What requirements should apply to emergency episodes?

    Currently, 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 human health. We anticipate proposing a separate rulemaking in
the future to update portions of that rule to address the 8-hour ozone
and PM2.5 NAAQS.

U. What ambient monitoring requirements will apply under the PM2.5
NAAQS?

    States are required to monitor PM2.5 mass concentrations
using Federal Reference Method devices to determine compliance with the
NAAQS.\120\ 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.
---------------------------------------------------------------------------

    \120\ 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.

IV. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866, [58 FR 51735 (October 4, 1993)] the
Agency must determine whether the regulatory action is ``significant''
and therefore subject to OMB review and the requirements of the
Executive Order. The Order defines ``significant regulatory action'' as
one that is likely to result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or
communities;
    (2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
    (4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
    Under the terms of Executive Order 12866, it has been determined
that this rule is a ``significant regulatory action.'' As such, this
action was submitted to OMB for EO 12866 review. Changes made in
response to OMB suggestions or recommendations will be documented in
the public record.

B. Paperwork Reduction Act

    The information collection requirements in this rule will be
submitted for approval to OMB under the Paperwork Reduction Act, 44
U.S.C. 3501 et seq. The information collection requirements are not
enforceable until OMB approves them other than to the extent required
by statute.
    This rule provides the framework for the States to develop SIPs to
achieve a new or revised NAAQS. This framework reflects the
requirements prescribed in CAA sections 110 and part D, subpart 1 of
title I. In that sense, the present final rule does not establish any
new information collection burden on States. Had this rule not been
developed, States would still have the legal obligation under law to
submit nonattainment area SIPs under part D of title I of the CAA
within specified periods after their nonattainment designation for the
PM2.5 standards, and the SIPs would have to meet the
requirements of part D.
    A SIP contains rules and other requirements designed to achieve the
NAAQS by the deadlines established under the CAA, and also contains a
demonstration that the State's requirements will in fact result in
attainment. The SIP must meet the CAA requirements in subpart 1 to
adopt RACM, RACT, and provide for RFP toward attainment for the period
prior to the area's attainment date. After a State submits a SIP, the
CAA requires EPA to approve or disapprove the SIP. If EPA approves the
SIP, the rules in the SIP become federally enforceable. If EPA
disapproves the SIP (or if EPA finds that a State fails to submit a
SIP), the CAA requires EPA to impose sanctions (2:1 offsets for major
new or modified sources and restrictions on Federal highway funding)
within specified timeframes; additionally, EPA must prepare and publish
a SIP within 2 years after a disapproval or finding of failure to
submit. The SIP must be publicly available. States must maintain
confidentiality of confidential business information, however, if used
to support SIP analyses. The SIP is a one-time submission, although the
CAA requires States to revise their SIPs if EPA requests a revision
upon a finding that the SIP is inadequate to attain or maintain the
NAAQS. The State may revise its SIP voluntarily as needed, but in doing
so must demonstrate that any revision will not interfere with
attainment or RFP or any other applicable requirement under the CAA
(see section 110(l)).
    This rule 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.
    The EPA has not yet projected cost and hour burden for the
statutory SIP development obligation but has started that effort and
will shortly prepare an Information Collection Request (ICR) request.
However, EPA did estimate administrative costs at the time of
promulgation of the PM2.5 standards in 1997. See Chapter 10
of U.S. EPA 1997, Regulatory Impact Analyses for the Particulate Matter
and Ozone National Ambient Air Quality Standards, Innovative Strategies
and Economics Group, Office of Air Quality Planning and Standards,
Research Triangle Park, N.C., July 16, 1997. Assessments of some of the
administrative cost categories identified as a part of the SIP for the
PM2.5 standards have already been conducted as a result of
other provisions of the CAA and associated ICRs (e.g., emission
inventory preparation, air quality monitoring program, conformity
assessments, NSR, I/M program).
    The burden estimates in the ICR for this rule are incremental to
what is required under other provisions of the CAA. 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. However, the failure to have an approved ICR for this rule
does not affect the statutory obligation for the States to submit SIPs
as required under part D of the CAA.
    The information collection requirements associated with NSR
permitting for ozone are covered by EPA's request to renew the approval
of the ICR for the NSR program, ICR 1230.17, which was approved by OMB
on January 25, 2005. The information collection requirements associated
with NSR permitting were previously covered by ICR 1230.10 and 1230.11.
The OMB previously approved the information collection requirements
contained in the existing NSR regulations at 40 CFR parts 51 and 52
under the provisions of the Paperwork Reduction Act, and assigned OMB
control number 2060-0003. A copy of the approved ICR may be obtained
from Susan Auby, Collection Strategies Division; U.S. Environmental
Protection Agency (2822T); 1200 Pennsylvania Ave., NW., Washington, DC
20460 or by calling<PHONE_NUMBER>.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act generally requires an Agency to
prepare a regulatory flexibility analysis of any rule subject to notice
and comment rulemaking requirements under the Administrative Procedures
Act or any other statute unless the Agency certifies the rule will not
have a significant economic impact on a substantial number of small
entities. Small entities include small businesses, small organizations,
and small governmental jurisdictions.
    For purposes of assessing the impacts of today's proposed rule on
small entities, small entity is defined as: (1) A small business that
is a small industrial entity as defined in the U.S. Small Business
Administration (SBA) size standards. (See 13 CFR part 121); (2) a
governmental jurisdiction that is a government of a city, county, town,
school district or special district with a population of less than
50,000; and (3) a small organization that is any not-for-profit
enterprise which is independently owned and operated and is not
dominant in its field.
    After considering the economic impacts of today's proposed rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. The proposed
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.
    Additionally, with respect to NSR, this proposed rule does not
itself create the obligation to obtain an NSR permit for new major
stationary sources and modifications resulting in emissions of
PM2.5 and its precursors. Rather, the preexisting rules
establish this obligation, and this proposed rule clarifies how that
obligation will be implemented.
    We believe that the existing Regulatory Flexibility Screening
Analysis (RFASA) further supports the conclusion that the NSR proposal
will not have a significant economic impact on a substantial number of
small entities. The RFASA, developed as part of a 1994 draft Regulatory
Impact Analysis (RIA) and incorporated into the September 1995 ICR
renewal analysis, showed that the changes to the NSR program due to the
1990 CAA Amendments would not have an adverse impact on small entities.
This analysis encompassed the entire universe of applicable major
sources that were likely to also be small businesses (approximately 50
``small business'' major sources). Because the administrative burden of
the NSR program is the primary source of the NSR program's regulatory
costs, the analysis estimated a negligible ``cost to sales''
(regulatory cost divided by the business category mean revenue) ratio
for this source group. Currently, there is no economic basis for a
different conclusion. We do not believe the number of ``small
business'' major sources will increase appreciably because all sources
who are major for PM2.5 or one of its precursors
(SO2, NOX, or VOC) will already be major for
PM10 or such precursor. We continue to be interested in the
potential impacts of the proposed rule on small entities and welcome
comments on issues related to such impacts.

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, section 205 of the UMRA generally requires EPA 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.
    The EPA has determined that this rule does not contain a 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 hour and
costs associated with implementing the PM2.5 NAAQS were
developed upon promulgation of the standard and presented in Chapter 10
of U.S. EPA 1997, Regulatory Impact Analyses for the Particulate Matter
and Ozone National Ambient Air Quality Standards, Innovative Strategies
and Economics Group, Office of Air Quality Planning and Standards,
Research Triangle Park, N.C., July 16, 1997. The estimated costs
presented there for States in 1990 dollars totaled $0.9 million. The
corresponding estimate in 1997 dollars is $1.1 million. Thus, today's
rule is not subject to the requirements of section 202 and 205 of the
UMRA.

    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)).
    In the proposal, EPA has determined that this proposed rule
contains no regulatory requirements that may significantly or uniquely
affect small governments, including Tribal governments. Nonetheless,
EPA carried out consultations with governmental entities affected by
this rule.

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.''
    This proposed rule does not have federalism implications. It will
not have substantial direct effects on the States, on the relationship
between the national government and the States, or on the distribution
of power and responsibilities among the various levels of government,
as specified in Executive Order 13132. As described in section D, above
(on UMRA), EPA previously determined the costs to States to implement
the PM2.5 NAAQS to be approximately $0.9 million in 1990
dollars. The corresponding estimate in 1997 dollars is $1.1 million.
While this proposed rule considers options not addressed at the time
the NAAQS were promulgated, the costs for implementation under these
options would rise only marginally. This rule clarifies the statutory
obligations of States in implementing the PM2.5 NAAQS.
Finally, the CAA establishes the scheme whereby States take the lead in
developing plans to meet the NAAQS. This proposed rule would not modify
the relationship of the States and EPA for purposes of developing
programs to implement the NAAQS. Thus, Executive Order 13132 does not
apply to this proposed rule.
    Although section 6 of Executive Order 13132 does not apply to this
rule, EPA actively engaged the States in the development of this
proposed rule. The EPA held a number of calls with representatives of
State and local air pollution control agencies.
    In the spirit of Executive Order 13132, and consistent with EPA
policy to promote communications between EPA and State and local
governments, EPA specifically solicits comment on this proposed rule
from State and local officials.

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 proposed 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.
    This proposed 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. 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.
    Although Executive Order 13175 does not apply to this rule, EPA did
reach out to Tribal leaders and environmental staff regarding this
proposal. The EPA supports a national ``Tribal Designations and
Implementation Work Group'' which provides an open forum for all Tribes
to voice concerns to EPA about the designations and implementation
process for the NAAQS, including the PM2.5 NAAQS. In
conference calls EPA briefed Work Group participants and Tribal
environmental professionals gave input as the rule was under
development. Furthermore, EPA is sending individualized letters to all
federally recognized Tribes about this proposal to give Tribal leaders
the opportunity for consultation. EPA specifically solicits additional
comment on this proposed rule from tribal officials.

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

    Executive Order 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.
    The proposed rule is not subject to Executive Order 13045.
Nonetheless, we have evaluated the environmental health or safety
effects of the PM2.5 NAAQS on children. The results of this
evaluation are contained in the 1997 Federal Register notice
establishing the PM2.5 standards.\121\ In a number of

locations in that notice, children are identified as one of the
principle sub-populations that are particularly sensitive to exposure
to fine particle pollution. Today's proposed rule provides the
framework by which States will require sources to reduce pollutant
emissions, thereby improving air quality and reducing the exposure of
children and others to unhealthy levels of fine particle pollution.
---------------------------------------------------------------------------

    \121\ 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 proposed 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.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer Advancement Act
of 1995 (NTTAA), Public Law 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 proposed 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 the
implementation plans.

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

    Executive Order 12898 requires that each Federal agency make
achieving environmental justice part of its mission by identifying and
addressing, as appropriate, disproportionate high and adverse human
health or environmental effects of its programs, policies, and
activities on minorities and low-income populations.
    The EPA believes that this proposed rule should not raise any
environmental justice issues. The health and environmental risks
associated with ozone were considered in the establishment of the
PM2.5 NAAQS. The level is designed to be protective with an
adequate margin of safety. The proposed rule provides a framework for
improving environmental quality and reducing health risks for areas
that may be designated nonattainment.

    Dated: September 8, 2005.
Stephen L. Johnson,
Administrator.

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

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

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

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

Subpart I--Review of New Sources and Modifications

    2. Section 51.165 is amended:
    a. By revising paragraphs (a)(1)(x), (a)(1)(xxxvii)(B),
(a)(1)(xxxvii)(C);
    b. By adding paragraphs (a)(1)(xxxvii)(D) and (a)(9); and
    c. By adding and reserving paragraph (a)(8) to read as follows:

Sec.  51.165  Permit requirements.

    (a) * * *
    (1) * * *
    (x) Significant means in reference to a net emissions increase or
the potential of a source to emit any of the following pollutants, a
rate of emissions that would equal or exceed any of the following
rates:

Pollutant Emission Rate

    Carbon monoxide: 100 tons per year (tpy).
    Nitrogen oxides: 40 tpy.
    Sulfur dioxide: 40 tpy.
    Ozone: 40 tpy of volatile organic compounds.
    Lead: 0.6 tpy.
    PM10: 15 tpy.
    PM2.5: 10 tpy of PM2.5 emissions; 40 tpy of
sulfur dioxide emissions; 40 tpy of nitrogen oxide emissions when
identified as a PM2.5 precursor under paragraph
(a)(1)(xxxvii)of this section.
* * * * *
    (xxxvii) * * *
    (B) Any pollutant for which a national ambient air quality standard
has been promulgated;
    (C) Any pollutant that is a constituent or precursor of a general
pollutant listed under paragraphs (a)(1)(xxxvii)(A) or (B) of this
section, provided that a constituent or precursor pollutant may only be
regulated under NSR as part of regulation of the general pollutant.
Precursors identified by the Administrator for purposes of NSR are the
following:
    (1) Volatile organic compounds and nitrogen oxides are precursors
to ozone in all ozone nonattainment areas.
    (2) Sulfur dioxide is a precursor to PM2.5 in all
PM2.5 nonattainment areas.
    (3) Nitrogen oxides are presumed to be precursors to
PM2.5 in all PM2.5 nonattainment areas, unless
the State demonstrates to the Administrator's satisfaction that
emissions of nitrogen oxides from stationary sources in a specific area
are not a significant contributor to that area's ambient
PM2.5 concentrations and the area is not in a State
identified by the Administrator as a source of a PM2.5
interstate transport problem.
    (4) Volatile organic compounds and ammonia are presumed not to be
precursors to PM2.5 in any PM2.5 nonattainment
area, unless the State demonstrates to the Administrator's satisfaction
that emissions of volatile organic compounds or ammonia from stationary
sources in a specific area are a significant contributor to that area's
ambient PM2.5 concentrations; or
    (D) Particulate matter (PM2.5 and PM10)
includes gaseous emissions from a source or activity which condense to
form particulate matter at ambient temperatures.
* * * * *
    (8) [Reserved.]
    (9) (i) The plan shall require that in meeting the emissions offset
requirements of paragraph (a)(3) of this section, the ratio of total
actual emissions reductions to the emissions increase shall be at least
1:1 unless an alternative ratio is provided for the applicable
nonattainment area in paragraph (a)(9)(ii) through (a)(9)(iv) of this
section.
    (ii) The plan shall require that in meeting the emissions offset
requirements of paragraph (a)(3) of this section for ozone
nonattainment areas that are subject to subpart 2, part D, title I of
the Act, the ratio of total actual emissions reductions of VOC to the
emissions increase of VOC shall be as follows:
    (A) In any marginal nonattainment area for ozone--at least 1.1:1;
    (B) In any moderate nonattainment area for ozone--at least 1.15:1;
    (C) In any serious nonattainment area for ozone--at least 1.2:1;
    (D) In any severe nonattainment area for ozone--at least 1.3:1
(except that the

ratio may be at least 1.2:1 if the approved plan also requires all
existing major sources in such nonattainment area to use BACT for the
control of VOC); and
    (E) In any extreme nonattainment area for ozone--at least 1.5:1
(except that the ratio may be at least 1.2:1 if the approved plan also
requires all existing major sources in such nonattainment area to use
BACT for the control of VOC); and
    (iii) Notwithstanding the requirements of paragraph (a)(9)(ii) of
this section for meeting the requirements of paragraph (a)(3) of this
section, the ratio of total actual emissions reductions of VOC to the
emissions increase of VOC shall be at least 1.15:1 for all areas within
an ozone transport region that is subject to subpart 2, part D, title I
of the Act, except for serious, severe, and extreme ozone nonattainment
areas that are subject to subpart 2, part D, title I of the Act.
    (iv) The plan shall require that in meeting the emissions offset
requirements of paragraph (a)(3) of this section for ozone
nonattainment areas that are subject to subpart 1, part D, title I of
the Act (but are not subject to subpart 2, part D, title I of the Act,
including 8-hour ozone nonattainment areas subject to 40 CFR
51.902(b)), the ratio of total actual emissions reductions of VOC to
the emissions increase of VOC shall be at least 1:1.
* * * * *
    3. Section 51.166 is amended:
    a. By adding paragraph (a)(6)(iv).
    b. By revising paragraphs (b)(23)(i), (b)(49)(i), (b)(49)(iii),
(i)(5)(ii), and (i)(5)(iii);
    c. By adding and reserving paragraph (b)(49)(v); and
    d. By adding paragraphs (b)(49)(vi) to read as follows:

Sec.  51.166  Prevention of significant deterioration of air quality.

    (a) * * *
    (6) * * *
    (iv) When an implementation plan must be amended to address the
prevention of significant deterioration of air quality for the
PM2.5 national ambient air quality standards, the
PM10 implementation plan provisions approved pursuant to
this section may be used to implement a PM2.5 program until
such amendments are approved, provided that: Particulate matter
emissions shall include gaseous emissions from a source or activity
which condense to form particulate matter at ambient temperatures for
purposes of determining applicability of prevention of significant
deterioration requirements; and the air quality analysis required under
paragraph (m) of this section shall be conducted with respect to the
PM2.5 standards.
* * * * *
    (b) * * *
    (23) (i) Significant means, in reference to a net emissions
increase or the potential of a source to emit any of the following
pollutants, a rate of emissions that would equal or exceed any of the
following rates:

Pollutant and Emissions Rate

    Carbon monoxide: 100 tons per year (tpy).
    Nitrogen oxides: 40 tpy.
    Sulfur dioxide: 40 tpy.
    Particulate matter: 25 tpy of particulate matter emissions. 15 tpy
of PM10 emissions.
    PM2.5: 10 tpy of PM2.5 emissions; 40 tpy of
sulfur dioxide emissions; 40 tpy of nitrogen oxide emissions when
identified as a PM2.5 precursor under paragraph (b)(49).
    Ozone: 40 tpy of volatile organic compounds.
    Lead: 0.6 tpy.
    Fluorides: 3 tpy.
    Sulfuric acid mist: 7 tpy.
    Hydrogen sulfide (H2 S): 10 tpy.
    Total reduced sulfur (including H2 S): 10 tpy.
    Reduced sulfur compounds (including H2 S): 10 tpy.
    Municipal waste combustor organics (measured as total tetra-through
octa-chlorinated dibenzo-p-dioxins and dibenzofurans): 3.2 x 10-6
megagrams per year (3.5 x 10-6 tons per year).
    Municipal waste combustor metals (measured as articulate matter):
14 megagrams per year (15 tons per year) Municipal waste combustor acid
gases (measured as sulfur dioxide and hydrogen chloride): 36 megagrams
per year (40 tons per year) Municipal solid waste landfill emissions
(measured as nonmethane organic compounds): 45 megagrams per year (50
tons per year).
* * * * *
    (49) Regulated NSR pollutant, for purposes of this section, means
the following:
    (i) Any pollutant for which a national ambient air quality standard
has been promulgated and any constituents or precursors to such
pollutants. Precursors identified by the Administrator for purposes of
NSR are the following:
    (A) Volatile organic compounds and nitrogen oxides are precursors
to ozone in all attainment and unclassifiable areas.
    (B) Sulfur dioxide is a precursor to PM2.5 in all
attainment and unclassifiable areas.
    (C) Nitrogen oxides are presumed precursors to PM2.5 in
all attainment and unclassifiable areas, unless the State demonstrates
to the Administrator's satisfaction that emissions of nitrogen oxides
from stationary sources in a specific area are not a significant
contributor to that area's ambient PM2.5 concentrations and
the area is not in a State identified by the Administrator as a source
of a PM2.5 interstate transport problem.
    (D) Volatile organic compounds are presumed not to be precursors to
PM2.5 in any attainment or unclassifiable area, unless the
State demonstrates to the Administrator's satisfaction that emissions
of volatile organic compounds from stationary sources in a specific
area are a significant contributor to that area's ambient
PM2.5 concentrations.
* * * * *
    (iii) Any Class I or II substance subject to a standard promulgated
under or established by title VI of the Act;
* * * * *
    (v) [Reserved.];
    (vi) Particulate matter (PM2.5 and PM10)
emissions include gaseous emissions from a source or activity which
condense to form particulate matter at ambient temperatures.
* * * * *
    (i) * * *
    (5) * * *
    (ii) The concentrations of the pollutant in the area that the
source or modification would affect are less than the concentrations
listed in paragraph (i)(5)(i) of this section; or
    (iii) The pollutant is not listed in paragraph (i)(5)(i) of this
section.
* * * * *
    5. A new Subpart Y is added to read as follows:
Subpart Y--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 Classifications.
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).

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

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.
    (a) Act means the Clean Air Act as codified at 42 U.S.C. 7401-
7671q. (2003).
    (b) Attainment year means the final year of the three consecutive
years evaluated to determine attainment with the PM2.5
NAAQS.
    (c) Benchmark RFP plan means the reasonable further progress plan
that requires generally linear emission reductions from the 2002
baseline emissions year through the emissions year preceding the RFP
milestone.
    (d) Date of designation means the effective date of the
PM2.5 area designation as promulgated by the Administrator.
    (e) Direct PM2.5 emissions means air pollutant emissions
of direct fine particulate matter, including organic carbon, elemental
carbon, direct sulfate, direct nitrate, and miscellaneous inorganic
material (i.e. crustal material).
    (f) 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 and
its precursors in a nonattainment area.
    (g) PM2.5 NAAQS means the particulate matter national
ambient air quality standards (annual and 24-hour) codified at 40 CFR
50.7.
    (h) 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.
    (i) PM2.5 direct emissions means solid particles emitted
directly from an emissions source or activity, or gaseous emissions or
liquid droplets from a source or activity which condense to form
particulate matter at ambient temperatures. PM2.5 direct
emissions include elemental carbon, directly emitted organic carbon,
and inorganic particles (including but not limited to crustal material,
metals, and sea salt).
    (j) PM2.5 nonattainment plan precursor means those
PM2.5 precursors emitted by sources in the State which the
State must evaluate for emission reduction measures.
    (k) PM2.5 precursor means those regulated air pollutants
other than PM2.5 direct emissions that contribute to the
formation of PM2.5. PM2.5 precursors include
SO2, NOX, volatile organic compounds, and
ammonia.
    (l) Reasonable further progress (RFP) means the incremental
emissions reductions toward attainment required under section 172(c)(2)
and section 171(1).
    (m) Subpart 1 means subpart 1 of part D of title I of the Act.

Sec.  51.1001  Applicability of Part 51.

    The provisions in subparts A-X of part 51 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 shall submit a State implementation
plan satisfying the requirements of section 172 of the Act and this
subpart Y of 40 CFR part 51 to EPA no later than 3 years from the
effective date of the 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) Precursors of fine particles. The state implementation plan
must identify and evaluate sources of PM2.5 direct emissions
and PM2.5 nonattainment plan precursors in accordance with
Sec. Sec.  51.1009 and 51.1010 of this subpart.
    (1) The State must address sulfur dioxide as a PM2.5
nonattainment plan precursor and evaluate SO2 emissions
sources for control measures.
    (2) The State must address NOX as a PM2.5
nonattainment plan precursor and evaluate sources of NOX
emissions sources for control measures, unless the State and EPA
provide an appropriate technical demonstration for a specific area
showing that NOX emissions do not significantly contribute
to the PM2.5 nonattainment problem in the area or to other
downwind air quality concerns.
    (3) The State is not required to address VOC as a PM2.5
nonattainment plan precursor and evaluate sources of VOC emissions for
control measures in that area, unless:
    (i) The State provides an appropriate technical demonstration for a
specific area showing that VOC emissions significantly contribute to
the PM2.5 nonattainment problem in the area or to other
downwind air quality concerns and such demonstration is approved by
EPA, or
    (ii) EPA provides such a technical demonstration.
    (4) The State is not required to address ammonia as a
PM2.5 nonattainment plan precursor and evaluate sources of
ammonia emissions for control measures in that area, unless:
    (i) the State provides an appropriate technical demonstration for a
specific area showing that ammonia emissions significantly contribute
to the PM2.5 nonattainment problem in the area or to other
downwind air quality concerns and such demonstration is approved by
EPA, or
    (ii) EPA provides such a technical demonstration.
    (5) Any technical demonstration referred to in paragraphs (c)(1)
through (c)(4) of this section to modify the presumptive approach for
any PM2.5 precursor must be considered in future SIP
development activities.

Sec.  51.1003.  Classifications.

    An area designated as nonattainment for the PM2.5 NAAQS
will not receive a specific classification based on design value.

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 shall be the date by which attainment can be achieved as
expeditiously as practicable. The attainment date presumptively shall
be 5 years or less from the date of designations. The Administrator may
approve an attainment date extension pursuant to section 172(a)(2)(A).
    (b) In the SIP submittal for each of its nonattainment areas, the
State shall submit an attainment demonstration providing detailed
information 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.

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/m\3\ 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/m\3\ 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 annual average concentration at each
monitor, averaged over both the original attainment year and the first
extension year, is 15.0 [mu]g/m\3\ 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 at each
monitor, averaged over both the original attainment year and the first
extension year, is 65 [mu]g/m\3\ 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 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
include modeling results, inventory data, and emission reduction
analyses on which the State has based its projected attainment date.
Such modeling must be consistent with EPA guidance and must be
appropriate for the area. 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 must be consistent with Appendix W of this part and EPA's most
recent modeling guidance in effect at the time the modeled attainment
demonstration is performed.
    (b) Required timeframe 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, the State shall:
    (1) Submit to EPA statewide emission inventories for
PM2.5 and its precursors under the Consolidated Emissions
Reporting Rule (CERR), 40 CFR part 51, subpart A.
    (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) 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 effective date
of an area's nonattainment 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 the
Consolidated Emissions Reporting Rule in subpart A of this part. The
baseline emission inventory for calendar year 2002 shall be used for
attainment planning and RFP plans for areas initially designated
nonattainment for the PM2.5 NAAQS.

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
defined in section 171(1).
    (b) Requirements for RFP plans.
    (1) If the State submits an attainment plan for an area which
proposes to attain the PM NAAQS within five years of the date of
designation and such plan is approved by EPA, then compliance with the
requirements of the attainment plan will be considered to also meet the
requirements for achieving reasonable further progress for that area.
    (2) For any area for which the State proposes an attainment date of
more than five years from the date of designation (i.e. attainment date
extension), the State must submit an RFP plan as part of its SIP
submittal. The SIP submittal is due to EPA within three years of the
date of designation.
    (3) The RFP plan must require generally linear progress in direct
PM2.5 and PM2.5 nonattainment plan precursor
emission reductions from the 2002 base year through the year preceding
the attainment date. For any area seeking an attainment date extension,
the RFP plan must include RFP emission reduction milestones and
projected air quality improvement to be achieved prior to January 1,
2010. Any area seeking an attainment date extension of three years or
more must also include in its plan RFP emission reduction milestones
and projected air quality improvement to be achieved prior to January
1, 2013. The State should develop these emission reduction milestones
from attainment year modeling analyses and the projected direct
PM2.5 and PM2.5 nonattainment plan precursor
emission reduction levels presented in the analyses.
    (4) In its RFP plan, the State must define the geographic area to
be covered by the inventories for each pollutant addressed in the plan.
For each pollutant, this area shall reflect the area for which the
emissions of that pollutant best corresponds with concentrations of the
associated ambient species in the nonattainment area, based on
information developed during attainment planning. In no case shall the
area be less than the nonattainment area. All emissions sources that
the State intends to track for RFP purposes must be included in the
2002 baseline inventory.
    (5) For any area seeking an attainment date extension beyond five
years from designation, the benchmark RFP plan due with the area's
attainment

demonstration shall include emission reduction milestones to be
achieved by January 1, 2010 and January 1, 2013, if applicable. The
following dates are defined for purposes of the benchmark RFP plan:
    (i) The baseline year for the benchmark RFP plan is the 2002
emissions year.
    (ii) The milestone date inventory is the emission inventory for the
year prior to the January 1 milestone date.
    (iii) The full implementation emission inventory is the emission
inventory for the year preceding the attainment date.
    (6) The plan shall address each emitted pollutant that is reduced
or otherwise affected by the control strategy of the PM2.5
attainment plan.
    (7) For each pollutant addressed pursuant to paragraph (b)(6) of
this section, an overall tonnage reduction shall be calculated by
subtracting the full implementation emission inventory from the
baseline year inventory.
    (8) 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.
    (9) For each pollutant addressed pursuant to paragraph (b)(6) of
this section, a benchmark tonnage emission reduction shall be
calculated by multiplying the full strategy tonnage reduction pursuant
to paragraph (b)(7) of this section times the milestone date fraction
pursuant to paragraph (b)(8) of this section. The benchmark emission
level for each pollutant as of the milestone date shall be determined
by subtracting the benchmark tonnage emission reduction from the
baseline year emission level. A benchmark RFP plan is defined as a plan
that achieves benchmark emission levels for each pollutant to be
addressed pursuant to paragraph (b)(6) of this section.
    (10) The RFP plan due at the time of the attainment demonstration
shall provide milestones that provide for emissions levels by January
1, 2010, to be either:
    (i) At levels that are roughly equivalent to the benchmark emission
levels defined in paragraph (b)(8) of this section for all applicable
pollutants; or
    (ii) At levels included in an alternative scenario that can be
shown to provide generally equivalent air quality protection as the
benchmark RFP plan.
    (11) The equivalence of an alternative scenario to the
corresponding benchmark plan shall be determined by comparing the
expected air quality benefits of the two scenarios at the design value
monitor location. This comparison shall use the information developed
for the attainment plan to assess the relationship between emissions
reductions of the regulated pollutants and the ambient air quality
improvement for the associated ambient species. The analysis of both
scenarios may use the linear assumption that achievement of a given
fraction of the emissions reductions of the attainment plan will
achieve the same fraction of the associated air quality improvement
that the attainment plan is demonstrated to achieve.

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

    (a) A PM2.5 nonattainment area that provides an
attainment demonstration proposing an attainment date no later than
five years from the date of designation is required to conduct RACT
determinations for major stationary sources and impose RACT controls
only to the extent that such controls are necessary to meet RFP or
attain the PM2.5 standards as expeditiously as practicable.
    (b) A PM2.5 nonattainment area that provides an
attainment demonstration proposing an attainment date of more than five
years but no later than ten years from the date of designation must
conduct a RACT determination for all stationary sources with the
potential to emit 100 tons or more of any one pollutant associated with
PM2.5 (direct PM2.5, SO2, and
NOX).
    (c) In any source-specific RACT determination, the State must
evaluate whether emission controls, process changes, or other emission
reduction measures are technically and economically feasible in
accordance with this rule and appropriate guidance. The State also must
consider any additional information obtained through public comments
when conducting RACT determinations for PM2.5. Any RACT
emission reduction regulations required by the State must be included
in the State's SIP submittal.
    (d) For any source that installed controls due to a previous RACT
determination for another NAAQS implementation program, the State may
accept the previous RACT determination for the purposes of the
PM2.5 program, provided it submits a certification with
appropriate supporting information that the previous RACT determination
currently represents an appropriate level of control for the
PM2.5 program.
    (e) 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 necessary
to demonstrate attainment as expeditiously as practicable and to meet
any RFP requirements. In developing its attainment demonstration, in
demonstrating attainment as expeditiously as practicable, and 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 and whether such measures taken together would
advance the attainment date by one year. In conducting a RACM analysis,
the State should consider control technology information available in
EPA and State guidance documents, in control technology clearinghouses,
and in any comments provided by the public.
    5. Appendix S to Part 51 is amended:
    a. By revising paragraph II. A. 10.;
    c. By adding paragraph II. A. 21.; and
    b. By revising paragraph IV. G. to read as follows:

Appendix S to Part 51--Emission Offset Interpretative Ruling

* * * * *
    II. * * *
    A. * * *
    10. Significant means, in reference to a net emissions increase or
the potential of a source to emit any of the following pollutants, a
rate of emissions that would equal or exceed any of the following
rates:

Pollutant and Emissions Rate

    Carbon monoxide: 100 tons per year (tpy) .
    Nitrogen oxides: 40 tpy.
    Sulfur dioxide: 40 tpy.
    Ozone: 40 tpy of volatile organic compounds.
    Lead: 0.6 tpy.
    Particulate matter: 25 tpy of particulate matter emissions.
    PM10: 15 tpy.
    PM2.5: 10 tpy of PM2.5 emissions; 40 tpy of
sulfur dioxide emissions; 40 tpy of nitrogen oxide emissions when
identified as a PM2.5 precursor under paragraph II. A. 21.
* * * * *
    21. Regulated NSR pollutant, for purposes of this section, means
the following:
    (i) Nitrogen oxides or any volatile organic compounds;
    (ii) Any pollutant for which a national ambient air quality
standard has been promulgated;
    (iii) Any pollutant that is a constituent or precursor of a general
pollutant listed under paragraphs II. A.

21. (i) or (ii) of this section, provided that a constituent or
precursor pollutant may only be regulated under NSR as part of
regulation of the general pollutant. Precursors identified by the
Administrator for purposes of NSR are the following:
    (a) Volatile organic compounds and nitrogen oxides are precursors
to ozone in all ozone nonattainment areas.
    (b) Sulfur dioxide is a precursor to PM2.5 in all
PM2.5 nonattainment areas.
    (c) Nitrogen oxides are presumed to be precursors to
PM2.5 in all PM2.5 nonattainment areas, unless
the State demonstrates to the Administrator's satisfaction that
emissions of nitrogen oxides from stationary sources in a specific area
are not a significant contributor to that area's ambient
PM2.5 concentrations and the area is not in a State
identified by the Administrator as a source of a PM2.5
interstate transport problem.
    (d) Volatile organic compounds and ammonia are presumed not to be
precursors to PM2.5 in any PM2.5 nonattainment
area, unless the State demonstrates to the Administrator's satisfaction
that emissions of volatile organic compounds or ammonia from stationary
sources in a specific area are a significant contributor to that area's
ambient PM2.5 concentrations; or
    (iv) Particulate matter (PM2.5 and PM10)
includes gaseous emissions from a source or activity which condense to
form particulate matter at ambient temperatures.
* * * * *
    IV. * * *
    G. Offset Ratios.
    1. In meeting the emissions offset requirements of paragraph IV.
A., Condition 3 of this Ruling, the ratio of total actual emissions
reductions to the emissions increase shall be at least 1:1 unless an
alternative ratio is provided for the applicable nonattainment area in
paragraphs IV. G. 2. to IV. G. 4.
    2. In meeting the emissions offset requirements of paragraph IV.
A., Condition 3 of this Ruling for ozone nonattainment areas that are
subject to subpart 2, part D, title I of the Act, the ratio of total
actual emissions reductions of VOC to the emissions increase of VOC
shall be as follows:
    (i) In any marginal nonattainment area for ozone--at least 1.1:1;
    (ii) In any moderate nonattainment area for ozone--at least 1.15:1;
    (iii) In any serious nonattainment area for ozone--at least 1.2:1;
    (iv) In any severe nonattainment area for ozone--at least 1.3:1
(except that the ratio may be at least 1.2:1 if the State also requires
all existing major sources in such nonattainment area to use BACT for
the control of VOC); and
    (v) In any extreme nonattainment area for ozone--at least 1.5:1
(except that the ratio may be at least 1.2:1 if the State also requires
all existing major sources in such nonattainment area to use BACT for
the control of VOC);
    3. Notwithstanding the requirements of paragraph IV.G. 2. of this
Ruling for meeting the requirements of paragraph IV. A., Condition 3 of
this Ruling, the ratio of total actual emissions reductions of VOC to
the emissions increase of VOC shall be at least 1.15:1 for all areas
within an ozone transport region that is subject to subpart 2, part D,
title I of the Act, except for serious, severe, and extreme ozone
nonattainment areas that are subject to subpart 2, part D, title I of
the Act.
    4. In meeting the emissions offset requirements of paragraph IV.
A., Condition 3 of this Ruling for ozone nonattainment areas that are
subject to subpart 1, part D, title I of the Act (but are not subject
to subpart 2, part D, title I of the Act, including 8-hour ozone
nonattainment areas subject to 40 CFR 51.902(b)), the ratio of total
actual emissions reductions of VOC to the emissions increase of VOC
shall be at least 1:1.

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

    5. The authority citation for part 52 continues to read as follows:

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

    6. Section 52.21 is amended by:
    a. Revising paragraphs (b)(23)(i), (b)(50)(i), (b)(50)(iii), and
(i)(5)(ii);
    b. Adding and reserving paragraph (b)(50)(v); and
    c. Adding paragraphs (b)(50)(vi) and (i)(5)(iii) to read as
follows:

Sec.  52.21  Prevention of significant deterioration of air quality.

* * * * *
    (b) * * *
    (23)(i) Significant means, in reference to a net emissions increase
or the potential of a source to emit any of the following pollutants, a
rate of emissions that would equal or exceed any of the following
rates:

Pollutant and Emissions Rate

    Carbon monoxide: 100 tons per year (tpy).
    Nitrogen oxides: 40 tpy.
    Sulfur dioxide: 40 tpy.
    Particulate matter: 25 tpy of particulate matter emissions.
    PM10: 15 tpy.
    PM2.5: 10 tpy of PM2.5 emissions; 40 tpy of
sulfur dioxide emissions; 40 tpy of nitrogen oxide emissions when
identified as a PM2.5 precursor under paragraph (b)(50) of
this section.
    Ozone: 40 tpy of volatile organic compounds.
    Lead: 0.6 tpy.
    Fluorides: 3 tpy.
    Sulfuric acid mist: 7 tpy.
    Hydrogen sulfide (H2 S): 10 tpy.
    Total reduced sulfur (including H2 S): 10 tpy.
    Reduced sulfur compounds (including H2 S): 10 tpy.
    Municipal waste combustor organics (measured as total tetra-through
octa-chlorinated dibenzo-p-dioxins and dibenzofurans): 3.2 x 10-6
megagrams per year (3.5 x 10-6 tons per year).
    Municipal waste combustor metals (measured as particulate matter):
14 megagrams per year (15 tons per year).
    Municipal waste combustor acid gases (measured as sulfur dioxide
and hydrogen chloride): 36 megagrams per year (40 tons per year).
    Municipal solid waste landfills emissions (measured as nonmethane
organic compounds): 45 megagrams per year (50 tons per year).
* * * * *
    (50) Regulated NSR pollutant, for purposes of this section, means
the following:
    (i) Any pollutant for which a national ambient air quality standard
has been promulgated and any constituents or precursors for such
pollutants. Precursors identified by the Administrator for purposes of
NSR are the following:
    (A) Volatile organic compounds and nitrogen oxides are precursors
to ozone in all attainment and unclassifiable areas.
    (B) Sulfur dioxide is a precursor to PM2.5 in all
attainment and unclassifiable areas.
    (C) Nitrogen oxides are presumed precursors to PM2.5 in
all attainment and unclassifiable areas, unless the State demonstrates
to the Administrator's satisfaction that emissions of nitrogen oxides
from stationary sources in a specific area are not a significant
contributor to that area's ambient PM2.5 concentrations and
the area is not in a State identified by the Administrator as a source
of a PM2.5 interstate transport problem.
    (D) Volatile organic compounds are presumed not to be precursors to
PM2.5 in any attainment or unclassifiable area, unless the
State demonstrates to the Administrator's satisfaction that emissions
of volatile organic compounds from stationary sources in a specific
area are a significant

contributor to that area's ambient PM2.5 concentrations.
* * * * *
    (iii) Any Class I or II substance subject to a standard promulgated
under or established by title VI of the Act;
* * * * *
    (v) [Reserved.];
    (vi) Particulate matter (PM2.5 and PM10)
emissions include gaseous emissions from a source or activity which
condense to form particulate matter at ambient temperatures.
* * * * *
    (i) * * *
    (5) * * *
    (ii) The concentrations of the pollutant in the area that the
source or modification would affect are less than the concentrations
listed in paragraph (i)(5)(i) of this section; or
    (iii) The pollutant is not listed in paragraph (i)(5)(i) of this
section.
* * * * *
[FR Doc. 05-20455 Filed 10-31-05; 8:45 am]

BILLING CODE 6560-50-U