Proposed Rule2022-04759
Air Plan Approval; Montana; Thompson Falls PM10 Nonattainment Area Limited Maintenance Plan and Redesignation Request
Primary source
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Published
March 8, 2022
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to fully approve the Limited Maintenance Plan (LMP) submitted by the State of Montana to EPA on November 4, 2021, for the Thompson Falls Moderate nonattainment area (NAA) for particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM<INF>10</INF>) and concurrently redesignate the NAA to attainment for the 24-hour PM<INF>10</INF> National Ambient Air Quality Standard (NAAQS). In order to approve the LMP and redesignation, EPA is proposing to determine that the Thompson Falls NAA has attained the 1987 24-hour PM<INF>10</INF> NAAQS of 150 [micro]g/m\3\. This determination is based upon monitored air quality data for the PM<INF>10</INF> NAAQS during the years 2015-2020. EPA is taking this action pursuant to the Clean Air Act (CAA).
Full Text
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<title>Federal Register, Volume 87 Issue 45 (Tuesday, March 8, 2022)</title>
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[Federal Register Volume 87, Number 45 (Tuesday, March 8, 2022)]
[Proposed Rules]
[Pages 12905-12912]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-04759]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 52 and 81
[EPA-R08-OAR-2021-0809; FRL-9579-01-R8]
Air Plan Approval; Montana; Thompson Falls PM10 Nonattainment
Area Limited Maintenance Plan and Redesignation Request
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
fully approve the Limited Maintenance Plan (LMP) submitted by the State
of Montana to EPA on November 4, 2021, for the Thompson Falls Moderate
nonattainment area (NAA) for particulate matter with an aerodynamic
diameter less than or equal to a nominal 10 micrometers
(PM<INF>10</INF>) and concurrently redesignate the NAA to attainment
for the 24-hour PM<INF>10</INF> National Ambient Air Quality Standard
(NAAQS). In order to approve the LMP and redesignation, EPA is
proposing to determine that the Thompson Falls NAA has attained the
1987 24-hour PM<INF>10</INF> NAAQS of 150 [micro]g/m\3\. This
determination is based upon monitored air quality data for the
PM<INF>10</INF> NAAQS during the years 2015-2020. EPA is taking this
action pursuant to the Clean Air Act (CAA).
DATES: Written comments must be received on or before April 7, 2022.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2021-0809 to the Federal Rulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="http://www.regulations.gov">www.regulations.gov</a>. The EPA may publish any comment received to its
public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or
[[Page 12906]]
comment contents located outside of the primary submission (i.e., on
the web, cloud, or other file sharing system). For additional
submission methods, the full EPA public comment policy, information
about CBI or multimedia submissions, and general guidance on making
effective comments, please visit <a href="https://www2.epa.gov/dockets/commenting-epa-dockets">https://www2.epa.gov/dockets/commenting-epa-dockets</a>.
Docket: All documents in the docket are listed in the
<a href="http://www.regulations.gov">www.regulations.gov</a> index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available electronically in
<a href="http://www.regulations.gov">www.regulations.gov</a>. To reduce the risk of COVID-19 transmission, for
this action we do not plan to offer hard copy review of the docket.
Please email or call the person listed in the FOR FURTHER INFORMATION
CONTACT section if you need to make alternative arrangements for access
to the docket.
FOR FURTHER INFORMATION CONTACT: Kate Gregory, Air and Radiation
Division, U.S. Environmental Protection Agency (EPA), Region 8, Mail
Code 8P-ARD-QP, 1595 Wynkoop Street, Denver, Colorado 80202-1129,
telephone number: (303) 312-6175, email address: <a href="/cdn-cgi/l/email-protection#4f283d2a28203d3661242e3b2a0f2a3f2e61282039"><span class="__cf_email__" data-cfemail="53342136343c212a7d38322736133623327d343c25">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
I. Background
Description of the Thompson Falls NAA
The Thompson Falls NAA is in Sanders County and is on the north
side of the Clark Fork River Valley in northwestern Montana. The Clark
Fork River has been dammed at the center of the small town of Thompson
Falls to form the Thompson Falls Reservoir and the configuration of the
nearby mountains and valley create temperature inversions in the fall
and winter months. The EPA promulgated the PM<INF>10</INF> NAAQS on
July 1, 1987 (52 FR 24634). The Thompson Falls NAA was originally
designated as a Group III area on July 1, 1987 (52 FR 24634), meaning,
at that time, there was a strong likelihood the Thompson Falls NAA
would attain the PM<INF>10</INF> NAAQS and, therefore, needed only
adjustments to their preconstruction permit review program and
monitoring network. However, multiple exceedances of the 1987 24-hour
PM<INF>10</INF> NAAQS resulted in nonattainment and subsequently the
Thompson Falls NAA was classified as Moderate for the 1987 24-hour
PM<INF>10</INF> NAAQS, effective January 20, 1994 (58 FR 67334). Within
18 months of this Moderate designation, by May 18, 1995, Montana was
required to submit to EPA a Moderate NAA State Implementation Plan
(SIP) for the Thompson Falls NAA containing, among other requirements,
provisions to assure that reasonably available control measures (RACM),
including reasonably available control technologies (RACT) and
demonstrated whether it was practicable to attain the PM<INF>10</INF>
NAAQS by December 31, 2000 (57 FR 13498 (April 16, 1992).\1\
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\1\ see also 57 FR 18070 (April 28, 1992) and 66 FR 55102
(November 1, 2001).
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The State of Montana submitted an initial PM<INF>10</INF> SIP to
EPA on June 26, 1997, and a subsequent submission on June 13, 2000. EPA
approved both the June 26, 1997 and the June 13, 2000 p.m.<INF>10</INF>
SIP submissions for the Thompson Falls initial control plan on April
24, 2008 (73 FR 22057). The State of Montana's SIP for the Thompson
Falls Moderate NAA included, but was not limited to, a comprehensive
emissions inventory, RACM (implemented by November 18, 1997), a
demonstration that attainment of the PM<INF>10</INF> NAAQS would be
achieved in Thompson Falls by December 31, 2000; Reasonable Further
Progress (RFP) requirements and control measures that satisfy the
contingency measures requirement of section 172(c)(9) of the CAA. The
EPA fully approved the Thompson Falls NAA PM<INF>10</INF> attainment
plan on January 22, 2004 (69 FR 3011).
II. Requirements for Redesignation
A. CAA Requirements for Redesignation of NAAs
NAAs can be redesignated to attainment after the area has measured
air quality data showing it has attained the NAAQS and when certain
planning requirements are met. Section 107(d)(3)(E) of the CAA, and the
General Preamble to Title I provide the criteria for redesignation. See
57 FR 13498 (April 16, 1992). These criteria are further clarified in a
policy and guidance memorandum from John Calcagni, Director, Air
Quality Management Division, EPA Office of Air Quality Planning and
Standards dated September 4, 1992, ``Procedures for Processing Requests
to Redesignate Areas to Attainment.'' \2\ The criteria for
redesignation are:
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\2\ The ``Procedures for Processing Requests to Redesignate
Areas to Attainment'' (Calcagni memo) outlines the criteria for
redesignation (see docket for memo).
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(1) The Administrator has determined that the area has attained the
applicable NAAQS;
(2) The Administrator has fully approved the applicable SIP for the
area under section 110(k) of the CAA;
(3) The state containing the area has met all requirements
applicable to the area under section 110 and part D of the CAA;
(4) The Administrator has determined that the improvement in air
quality is due to permanent and enforceable reductions in emissions;
and
(5) The Administrator has fully approved a maintenance plan for the
area as meeting the requirements of section 175A of the CAA.
B. The LMP Option for PM10 NAAs
On August 9, 2001, the EPA issued guidance on streamlined
maintenance plan provisions for certain moderate PM<INF>10</INF> NAAs
seeking redesignation to attainment (Memo from Lydia Wegman, Director,
Air Quality Standards and Strategies Division, entitled ``Limited
Maintenance Plan Option for Moderate PM<INF>10</INF> Nonattainment
Areas,'' (hereafter the LMP Option memo)).\3\ The LMP Option memo
contains a statistical demonstration to show that areas meeting certain
air quality criteria will, with a high degree of probability, maintain
the standard 10 years into the future. Thus, the EPA has already
provided the maintenance demonstration for areas meeting the criteria
outlined in the LMP Option memo. It follows that future year emission
inventories for these areas, and some of the standard analyses to
determine transportation conformity with the SIP are no longer
necessary.
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\3\ The ``Limited Maintenance Plan Option for Moderate
PM<INF>10</INF> Nonattainment Areas'' outlines the criteria for
development of a PM<INF>10</INF> limited maintenance plan (see
docket for memo).
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To qualify for the LMP Option, the area should have attained the
1987 24-hour PM<INF>10</INF> NAAQS, based upon the most recent 5 years
of air quality data at all monitors in the area, and the 24-hour design
concentration should be at or below the ``Critical Design Value''
(CDV). The CDV is a calculated design concentration that indicates that
the area has a low probability (1 in 10) of exceeding the NAAQS in the
future. For the purposes of qualifying for the LMP option, a
presumptive CDV of 98 [micro]g/m\3\ is most often employed, but an area
may elect to use a site-specific CDV should the average design
concentration (ADC) be above 98 [micro]g/m\3\, while demonstrating that
the area has a low probability of exceeding the NAAQS in the future.
The annual PM<INF>10</INF> standard was effectively
[[Page 12907]]
revoked on December 18, 2006 (71 FR 61143), and as such will not be
discussed as a requirement for qualifying for the LMP option. In
addition, the area should expect only limited growth in on-road motor
vehicle PM<INF>10</INF> emissions (including fugitive dust) and should
have passed a motor vehicle regional emissions analysis test. The LMP
Option memo also identifies core provisions that must be included in
the LMP. These provisions include an attainment year emissions
inventory, assurance of continued operation of an EPA-approved air
quality monitoring network, and contingency provisions.
III. Review of Montana's Submittal Addressing the Requirements for
Redesignation and Limited Maintenance Plan
A. Has the Thompson Falls NAA attained the applicable NAAQS?
States must demonstrate that an area has attained the 24-hour
PM<INF>10</INF> NAAQS through analysis of ambient air quality data from
an ambient air monitoring network representing peak PM<INF>10</INF>
concentrations. The data should be stored in the EPA Air Quality System
(AQS) database. The request for redesignation of the Thompson Falls
PM<INF>10</INF> NAA submitted by the State of Montana presented data
and analyses to demonstrate that the area attained the PM<INF>10</INF>
standard using 2015-2019 data. During the review process the EPA
identified a single 2017 24-hour PM<INF>10</INF> data point that was
inadvertently omitted from the submission, and therefore this datapoint
was included in the tables and calculations contained in this action.
In addition to reviewing the 2015-2019 data the EPA included 2020
p.m.<INF>10</INF> data in this action (as it is currently the most
recent year of certified data present in AQS) to confirm that the area
is still attaining the 24-hour PM<INF>10</INF> NAAQS. Additionally,
preliminary 2021 data indicates the area continues to attain.
Today, EPA is proposing to determine that the Thompson Falls NAA
has attained the 24-hour PM<INF>10</INF> NAAQS based on monitoring data
from calendar years 2015-2020. The 24-hour standard is attained when
the expected number of days with 24-hour average concentrations above
150 [micro]g/m\3\ (averaged over a 3-year period) is less than or equal
to one. See 40 CFR 50.6(a). A minimum of three complete and consecutive
years of air quality data are generally necessary to show attainment of
the standard. See 40 CFR part 50, appendix K. A complete year of air
quality data, as referred to in 40 CFR part 50, appendix K, is
comprised of all four calendar quarters with each quarter containing
data from at least 75% of the scheduled sampling days.
The Thompson Falls NAA has one State and Local Air Monitoring
Station (SLAMS) PM<INF>10</INF> monitor, Thompson Falls High School
(AQS ID 30-089-0007), operated by the Montana Department of
Environmental Quality (MDEQ). Table 1 summarizes the PM<INF>10</INF>
data collected from 2015-2020 for the Thompson Falls NAA. The EPA deems
the data collected from these monitors valid, and the data have been
submitted and certified by the MDEQ to be included in AQS. All years
are complete except for 2016 which has one incomplete quarter of data.
Therefore, the State performed data substitution for the missing 2016
data. Methods and results for the missing 2016 data substitution can be
found in Appendix E of the State submission in the docket of this
action.
Table 1--Summary of Maximum 24-Hour PM10 Concentrations ([mu]g/m\3\), Design Concentrations ([mu]g/m\3\), and
Number of Exceedances for Thompson Falls 2015-2020
[Based on data from Thompson Falls High School, AQS Identification Number (30-089-0007)]
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Number of exceedances
Design concentration excluding regionally
Year Maximum concentration \4\ concurred exceptional
events \5\
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2015................................. 143 135 0
2016................................. 135 135 0
2017................................. 210 135 1
2018................................. 72 135 0
2019................................. 43 72 0
2020................................. 148 99 0
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The CAA allows for the exclusion of air quality monitoring data
from design value calculations when there are exceedances caused by
exceptional events, including for expected number exceedances for
PM<INF>10</INF> averaged over a 3-year period, that meet the criteria
for an exceptional event identified in the EPA's implementing
regulations, the Exceptional Events Rule at 40 CFR 50.1, 50.14, and
51.930. For the purposes of this proposed action, on November 23, 2021,
the State of Montana submitted exceptional event demonstrations to
request exclusion of data impacted by wildfires. The EPA evaluated the
State of Montana's exceptional event demonstrations for the flagged
values of the 24-hour PM<INF>10</INF> listed in Table 3 below in the
Thompson Falls Moderate NAA, with respect to the requirements of EPA's
Exceptional Events Rule (40 CFR 50.1, 50.14, and 50.930).
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\4\ The design concentrations are calculated using three years
of data and the ``Table Look-up'' method described in the
``PM<INF>10</INF> SIP Development Guideline'', EPA-450/2-86-001,
June 1987.
\5\ Exceedances in 2017 and 2020 have been flagged and concurred
on as exceptional events. Additional information on 2017 data can be
found in Appendix A, p. a-1, of the submission by the state in the
docket of this action and additional information on 2020 data can be
found in the docket for this action, document titled: Montana 2020
p.m.<INF>10</INF> Letter.
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On January 25, 2022, EPA concurred with the State of Montana's
requests to exclude event-influenced data listed in Table 3, finding
that the State of Montana's demonstration met the Exceptional Event
Rule criteria. As such, the event-influenced data have been removed
from the data set used for regulatory purposes. For this proposed
action, EPA relies on the PM<INF>10</INF> concentrations reported at
the Thompson Falls monitoring site which showed only one exceedance
from 2015-2020 when exceptional events are excluded. Therefore, the
expected number of days with 24-hour average concentrations above 150
[micro]g/m\3\ averaged over a 3-year period is less than one, and as
such, the EPA proposes to determine that the Thompson Falls NAA has
attained the standard for the 24-hour PM<INF>10</INF> NAAQS.\6\
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\6\ Please see section III(F) of this action for further
discussion and description of exceptional events in the Thompson
Falls NAA during the 2015-2020 time period.
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[[Page 12908]]
Additionally, the EPA concurred on the State of Montana's request
to exclude PM<INF>10</INF> data listed in Table 3 in regulatory
decisions. For further information, refer to the State of Montana's
Exceptional Event demonstration packages and the EPA's concurrence and
analyses located in the docket for this proposed action.
B. Does the Thompson Falls NAA have a fully approved SIP under CAA
section 110(k)?
To qualify for redesignation, the SIP for the area must be fully
approved under CAA section 110(k) and must satisfy all requirements
that apply to the area. Section 189 of the CAA contains requirements
and milestones for all initial Moderate NAA SIPs including: (1)
Provisions to assure that RACM (including such reductions in emissions
from existing sources in the area as may be obtained through the
adoption, at a minimum, of RACT shall be implemented no later than
December 10, 1993; (2) A demonstration (including air quality modeling)
that the plan will provide for attainment as expeditiously as
practicable by no later than December 31, 1994, or, where the state is
seeking an extension of the attainment date under section 188(e), a
demonstration that attainment by December 31, 1994, is impracticable
and that the plan provides for attainment by the most expeditious
alternative date practicable (CAA sections 189(a)(1)(A)); (3)
Quantitative milestones which are to be achieved every 3 years and
which demonstrate RFP toward attainment by December 31, 1994, (CAA
sections 172(c)(2) and 189(c)); and (4) Contingency measures to be
implemented if the area fails to make RFP or attain by its attainment
deadline. These contingency measures are to take effect without further
action by the state or the EPA. (CAA section 172(c)(9)).
The EPA fully approved the Thompson Falls NAA PM<INF>10</INF>
attainment plan on January 22, 2004 (69 FR 3011). The Thompson Falls
plan included RACM, an attainment demonstration, emissions inventory,
quantitative milestones, and control and contingency measure
requirements. As such, the area has a fully approved NAA SIP under
section 110(k) of the CAA.
C. Has the state met all applicable requirements under section 110 and
Part D of the CAA?
Section 107(d)(3)(E) of the CAA requires that a state containing a
NAA must meet all applicable requirements under section 110 and Part D
of the CAA for an area to be redesignated to attainment. The EPA
interprets this to mean that the state must meet all requirements that
applied to the area prior to, and at the time of, the submission of a
complete redesignation request. The following is a summary of how
Montana meets these requirements.
1. CAA Section 110 Requirements
Section 110(a)(2) of the CAA contains general requirements for
SIPs. These requirements include, but are not limited to, submittal of
a SIP that has been adopted by the state after reasonable notice and
public hearing, provisions for establishment and operation of
appropriate apparatus, methods, systems and procedures necessary to
monitor ambient air quality, implementation of a permit program,
provisions for Part C--Prevention of Significant Deterioration (PSD)
and Part D--New Source Review (NSR) permit programs, criteria for
stationary source emission control measures, monitoring and reporting,
provisions for modeling and provisions for public and local agency
participation. See the General Preamble for further explanation of
these requirements. See 57 FR 13498 (April 16, 1992).
For purposes of redesignation, the EPA's review of the Montana SIP
shows that the State has satisfied all requirements under section
110(a)(2) of the CAA. Further, in 40 CFR 52.1372, the EPA has approved
Montana's plan for the attainment and maintenance of the national
standards under section 110.
2. Part D Requirements
Part D contains general requirements applicable to all areas
designated nonattainment. The general requirements are followed by a
series of subparts specific to each pollutant. All PM<INF>10</INF> NAAs
must meet the general provisions of Subpart 1 and the specific
PM<INF>10</INF> provisions in Subpart 4, ``Additional Provisions for
Particulate Matter Nonattainment Areas.'' The following paragraphs
discuss these requirements as they apply to the Thompson Falls NAA.
3. Subpart 1, Section 172(c)
Subpart 1, section 172(c) contains general requirements for NAA
plans. A thorough discussion of these requirements may be found in the
General Preamble. See 57 FR 13538 (April 16, 1992). CAA section
172(c)(2) requires nonattainment plans to provide for RFP. Section
171(1) of the CAA defines RFP as ``such annual incremental reductions
in emissions of the relevant air pollutant as are required by this part
(part D of title I) or may reasonably be required by the Administrator
for the purpose of ensuring attainment of the applicable national
ambient air quality standard by the applicable date.'' Since EPA is
proposing to determine that the Thompson Falls NAA is in attainment of
the PM<INF>10</INF> NAAQS, we believe that no further showing of RFP or
quantitative milestones is necessary.
4. Section 172(c)(3)--Emissions Inventory Section
Section 172(c)(3) of the CAA requires a comprehensive, accurate,
current inventory of actual emissions from all sources in the Thompson
Falls PM<INF>10</INF> NAA. Montana included an emissions inventory for
the calendar year 2017 with the November 4, 2021submittal of the LMP
for the NAA. The LMP Option memo states that an attainment inventory
should represent emissions during the same 5-year period associated
with the air quality data used to determine that the area meets the
applicability requirements of the LMP option. The Thompson Falls LMP
includes an emission inventory from 2017, representative of the 2015-
2019 5-year period which served as the 5-year period relied upon in the
LMPs as meeting the air quality data requirements of the LMP option
memo.\7\
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\7\ The emissions inventory included in the Thompson Falls MT
submission is the 2017 National Emissions Inventory (NEI). The NEI
is a composite of data from many different sources, with PM data
coming primarily from EPA models as well as from state, tribal, and
local air quality management agencies. Different data sources use
different data collection methods, and many of the emissions data
are based on estimates rather than actual measurements. The EPA
considers the 2017 NEI representative of the period from 2015--2019
because MT provided comparable vehicle miles traveled (VMT) data in
their submission. See Thompson Falls, MT Submission, Appendix C,
Montana Department of Transportation Future VMT Projections, p.C-1
in docket.
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5. Section 172(c)(5)--NSR
The 1990 CAA Amendments contained revisions to the NSR program
requirements for the construction and operation of new and modified
major stationary sources located in NAAs. The CAA requires states to
amend their SIPs to reflect these revisions but does not require
submittal of this element along with the other SIP elements. The CAA
established June 30, 1992, as the submittal date for the revised NSR
programs (section 189 of the CAA).
Montana has a fully approved nonattainment NSR program, approved on
August 30, 1995 (60 FR 45051). Montana also has a fully approved PSD
[[Page 12909]]
program, approved on August 30, 1995 (60 FR 45051). Upon the effective
date of redesignation of an area from nonattainment to attainment, the
requirements of the Part D NSR program will be replaced by the PSD
program and the maintenance area NSR program.
6. Section 172(c)(7)--Compliance With CAA Section 110(a)(2): Air
Quality Monitoring Requirements
Once an area is redesignated, the state must continue to operate an
appropriate air monitoring network in accordance with 40 CFR part 58 to
verify attainment status of the area. The State of Montana operates one
PM<INF>10</INF> SLAMS in each of the NAAs. The Thompson Falls
monitoring site meets EPA SLAMS network design and siting requirements
set forth at 40 CFR part 58, appendices D and E. In section 3.5 of the
LMP that we are proposing to approve, the State commits to continued
operation of the monitoring network.
7. Section 172(c)(9)--Contingency Measures
The CAA requires that contingency measures take effect if the area
fails to meet RFP requirements or fails to attain the NAAQS by the
applicable attainment date. Since the Thompson Falls NAA has attained
the 1987 24-hour PM<INF>10</INF> NAAQS, contingency measures are no
longer required under section 172(c)(9) of the CAA. However,
contingency provisions are required for maintenance plans under section
175(a)(d). We describe the contingency provisions Montana provided in
the LMP section below.
8. Part D, Subpart 4
Part D, subpart 4, section 189(a), (c) and (e) requirements apply
to any Moderate NAA before the area can be redesignated to attainment.
The requirements which were applicable prior to the submission of the
request to redesignate the area must be fully approved into the SIP
before redesignating the area to attainment. These requirements
include: (a) Provisions to assure that RACM was implemented by December
10, 1993; (b) Either a demonstration that the plan provided for
attainment as expeditiously as practicable but not later than December
31, 1994, or a demonstration that attainment by that date was
impracticable; (c) Quantitative milestones which were achieved every 3
years and which demonstrate RFP toward attainment by December 31, 1994;
and (d) Provisions to assure that the control requirements applicable
to major stationary sources of PM<INF>10</INF> also apply to major
stationary sources of PM<INF>10</INF> precursors except where the
Administrator determined that such sources do not contribute
significantly to PM<INF>10</INF> levels which exceed the NAAQS in the
area. These provisions were fully approved into the SIP upon the EPA's
approval of the PM<INF>10</INF> Moderate area plan for the Thompson
Falls NAA on January 22, 2004 (69 FR 3011).
D. Has the state demonstrated that the air quality improvement is due
to permanent and enforceable reductions?
A state must be able to reasonably attribute the improvement in air
quality to permanent and enforceable emission reductions. In making
this showing, a state must demonstrate that air quality improvements
are the result of actual enforceable emission reductions. This showing
should consider emission rates, production capacities, and other
related information. The analysis should assume that sources are
operating at permitted levels (or historic peak levels) unless evidence
is presented that such an assumption is unrealistic. Permanent and
enforceable control measures in the Thompson Falls NAA SIP includes
RACM. Emission sources in the NAA have been implementing RACM for at
least 10 years.
Areas that qualify for the LMP will meet the NAAQS, even under
worst case meteorological conditions. Under the LMP option, the
maintenance demonstration is presumed to be satisfied if an area meets
the qualifying criteria. Thus, by qualifying for the LMP, Montana has
demonstrated that the air quality improvements in the Thompson Falls
NAA is the result of permanent emission reductions and not a result of
either economic trends or meteorology. A description of the LMP
qualifying criteria and how the Thompson Falls area meets these
criteria is provided in the following section.
Permanent and enforceable emission reductions in the Thompson Falls
NAA have reduced emissions 29% since the 1991 baseline. The primary
controls incorporated into the SIP included rules focused on reducing
fugitive dust emissions from roads and parking lots. Additionally, the
approved control plan satisfied the requirements for RACM of area
sources. Based on the 2017 national emissions inventory,
PM<INF>10</INF> emissions in all source areas are below the levels
approved in the original control plan.\8\
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\8\ See Thompson Falls, MT submission in docket, Table 2.4--
Thompson Falls, MT--PM<INF>10</INF> Emission Summary, p. 2-5.
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E. Does the area have a fully approved maintenance plan pursuant to
section 175A of the CAA?
In this action, we are proposing to approve the LMP for the
Thompson Falls NAA in accordance with the principles outlined in the
LMP Option.
F. Has the state demonstrated that the Thompson Falls NAA qualifies for
the LMP Option?
The LMP Option memo outlines the requirements for an area to
qualify for the LMP Option. First, the area should be attaining the
NAAQS. As stated above in section III. A., the EPA has determined that
the Thompson Falls NAA is attaining the PM<INF>10</INF> NAAQS.
Second, the ADC for the past 5 years of monitoring data must be at
or below the CDV. As noted in section II.B., the CDV is a margin of
safety value and is the value at which an area has been determined to
have a 1 in 10 probability of exceeding the NAAQS. The LMP Option memo
provides two methods for review of monitoring data for the purpose of
qualifying for the LMP option. The first method is a comparison of a
site's ADC with the CDV of 98 [micro]g/m\3\ for the 24-hour
PM<INF>10</INF> NAAQS. A second method that applies to the 24-hour
PM<INF>10</INF> NAAQS is the calculation of a site-specific CDV and a
comparison of the site-specific CDV with the ADC for the past 5 years
of monitoring data. Table 2 below outlines the design concentrations
for the years 2015-2020 and presents the ADC.
Table 3 summarizes the wildfire related events that were excluded
from the calculated design concentrations in Table 2. Table 3 includes
all regionally concurred exceptional events, as well as values between
98 [mu]g/m\3\ and 155 [mu]g/m\3\, which were treated in a manner
analogous to exceedance data under the Exceptional Events Rule for the
purpose of determining the LMP option eligibility. The values between
98 [mu]g/m\3\ and 155 [mu]g/m\3\ remain in the AQS database for use in
calculating design concentrations for every purpose besides determining
LMP eligibility.\9\ The Exceptional Events Rule can be found in 40 CFR
50.14 and 40 CFR 51.930, and outlines the requirements for the
treatment of monitored air quality data that has been heavily
influenced by an exceptional event. 40 CFR 50.1(j) defines an
exceptional event as an event which affects air quality, is not
reasonably controllable or preventable, is an event caused by
[[Page 12910]]
human activity that is unlikely to recur at a particular location or a
natural event and is determined by the Administrator in accordance with
40 CFR 50.14 to be an exceptional event. Exceptional events do not
include stagnation of air masses or meteorological inversions,
meteorological events involving high temperatures or lack of
precipitation, or air pollution relating to source noncompliance. 40
CFR 50.14(b) states that the EPA shall exclude data from use in
determinations of exceedances and NAAQS violations where a state
demonstrates to the EPA's satisfaction that an exceptional event caused
a specific air pollution concentration in excess of one or more NAAQS
at a particular air quality monitoring location and otherwise satisfies
the requirements of section 50.14. Table 3 below includes some values
between 98 [mu]g/m\3\ and 155 [mu]g/m\3\ that were excluded for the
sole purpose of determining PM<INF>10</INF> LMP eligibility in
accordance with the LMP guidance.\10\ Supporting documentation of EPA's
concurrence with the wildfire related events can be found in the
docket.\11\
---------------------------------------------------------------------------
\9\ Update on Application of the Exceptional Events Rule to the
PM<INF>10</INF> Limited Maintenance Plan Option, US EPA, William T.
Harnett, Director, Air Quality Policy Division, OAQPS, May 7, 2009.
\10\ See Update on Application of the Exceptional Events Rule to
the PM<INF>10</INF> Limited Maintenance Plan Option, US EPA, William
T. Harnett, Director, Air Quality Policy Division, OAQPS, May 7,
2009 and Additional Methods, Determinations, and Analyses to Modify
Air Quality Data Beyond Exceptional Events, US EPA, Richard Wayland,
Director, Air Quality Assessment Division and Anna Marie Wood,
Director, Air Quality Policy Division, April 4, 2019 memos in
docket.
\11\ February 8, 2019 letter to MDEQ, Re: Exceptional Events
Requests Regarding Exceedances of the 24-hour PM<INF>10</INF> NAAQS
and the LMP Eligibility Threshold at Montana Monitoring Sites with
PM<INF>10</INF> Nonattainment Areas; and November 1, 2018 letter to
MDEQ, Re: Request for EPA concurrence on exceptional event claims
for fine (PM<INF>2.5</INF>) and coarse (PM<INF>10</INF>) particulate
matter data impacted by wildfires in 2015 and 2016. See Thompson
Falls, MT submission in docket; and additional information on 2020
data can be found in the docket for this action, document titled:
Montana 2020 PM<INF>10</INF> Letter.
Table 2--Summary of 24-Hour PM10 Design Concentrations ([mu]g/m\3\) for
Thompson Falls
[Based on data from Thompson Falls HS Site, AQS Identification Number
(30-089-0007)]
------------------------------------------------------------------------
Design
Design concentration years concentration
([mu]g/m\3\)
------------------------------------------------------------------------
2015-2017............................................ 100
2016-2018............................................ 88
2017-2019............................................ 70
2018-2020............................................ 66
------------------------------------------------------------------------
Average Design Concentration (of Most Recent 3 Design Concentrations) 75
[mu]g/m\3\.
Table 3--Thompson Falls 24-Hour PM10 Events Excluded From the 2015-2020
Data for the Purpose of Determining LMP Eligibility
[Based on data from Thompson Falls HS Site, AQS Identification Number
(30-089-0007)]
------------------------------------------------------------------------
24-hour value
Date ([mu]g/m\3\)
------------------------------------------------------------------------
8-14-2016............................................ 105
8-24-2015............................................ 117
8-26-2015............................................ 135
8-27-2015............................................ 122
8-29-2015............................................ 143
8-30-2016............................................ 135
9-6-2017............................................. 251
9-7-2017............................................. 231
9-8-2017............................................. 249
9-9-2017............................................. 100
9-12-2020............................................ 168
9-13-2020............................................ 206
9-14-2020............................................ 185
9-15-2020............................................ 148
9-16-2020............................................ 103
9-17-2020............................................ 107
9-18-2020............................................ 99
------------------------------------------------------------------------
Values between 98 [micro]g/m\3\ and 155 [micro]g/m\3\ were excluded by
EPA solely for the purpose of determining limited maintenance plan
(LMP) eligibility in accordance with LMP guidance. The values remain
in AQS and are still used for all other purposes (including
calculating the estimated exceedances and official design
concentrations).
The ADC for the 24-hour PM<INF>10</INF> NAAQS for Thompson Falls,
based on data from the SLAMS monitor for the years 2016-2020 is 75
[mu]g/m\3\. This value falls below the presumptive 24-hour CDV of 98
[mu]g/m\3\ and would meet the first threshold for LMP eligibility.
In addition to having an ADC that is below the presumptive or area
specific CDV, and in order to qualify for the LMP, the area must meet
the motor vehicle regional emissions analysis test in attachment B of
the LMP Option memo. Using the methodology outlined in the memo, the
data presented in the State submission in section 3.2 and based on
monitoring data for the period 2016-2020, the EPA has determined that
the Thompson Falls NAA has a projected design concentration of 79
[mu]g/m\3\ after 10 years, attributable to motor vehicle emission
growth. This value is below the presumptive 24-hour CDV of 98 [mu]g/
m\3\ and therefore passes the motor vehicle regional emissions analysis
test. For the detailed calculations used to determine how the Thompson
Falls NAA passed the motor vehicle regional analysis test, see the
supporting documents in the docket.\12\
---------------------------------------------------------------------------
\12\ See memo to file in docket dated January 10, 2022 titled
``Memo to File--Thompson Falls, MT Motor Vehicle Regional Emissions
Analysis.''
---------------------------------------------------------------------------
The State's submission demonstrated that the 2015-2019 monitoring
data shows that Thompson Falls has attained the 24-hour NAAQS for
PM<INF>10</INF>, and the 24-hour ADC for the area is less than the 24-
hour PM<INF>10</INF> presumptive and area-specific CDV. The data
presented in this action demonstrates that the 2016-2020 data show that
Thompson Falls has attained the 24-hour NAAQS for PM<INF>10</INF>, and
the 24-hour ADC for the area is less that the 24-hour PM<INF>10</INF>
presumptive CDV of 98 [mu]g/m\3\. Finally, the area has met the
regional vehicle emissions analysis test for both the 2015-2019 and
2016-2020 periods of monitoring data. Thus, the Thompson Falls NAA
qualifies for the LMP Option described in the LMP Option memo. The LMP
Option memo also indicates that once a state selects the LMP Option and
it is in effect, the state will be expected to determine, on an annual
basis, that the LMP criteria are still being met. If a state determines
that the LMP criteria are not being met, it should take action to
reduce PM<INF>10</INF> concentrations enough to requalify for the LMP.
One possible approach a state could take is to implement contingency
measures. Please see section 3.6 of the Thompson Falls LMP for a
description of contingency provisions submitted as part of the State's
submittal.
G. Does the state have an approved attainment emissions inventory which
can be used to demonstrate attainment of the NAAQS?
A state's approved attainment plan should include an emissions
inventory (attainment inventory) which can be used to demonstrate
attainment of the NAAQS. The inventory should represent emissions
during the same 5-year period associated with air quality data used to
determine whether the area meets the applicability requirements of the
LMP Option. A state should review its inventory every 3 years to ensure
emissions growth is incorporated in the attainment inventory if
necessary. In this instance, Montana completed an attainment year
inventory for the attainment year 2017 for the Thompson Falls NAA. The
EPA has reviewed the 2017 emissions inventories and determined that
they are current, accurate and complete. In addition, the emissions
inventory submitted with the LMP for the calendar year 2017 is
representative of the level of emissions during the time period used to
calculate the ADC since 2017 is included in the 5-year period used to
calculate the design concentrations (2015-2019).
[[Page 12911]]
H. Does the LMP include an assurance of continued operation of an
appropriate EPA-approved air quality monitoring network, in accordance
with 40 CFR Part 58?
The PM<INF>10</INF> monitoring network for the Thompson Falls NAA
has been developed and maintained in accordance with federal siting and
design criteria in 40 CFR part 58, appendices D and E and in
consultation with the EPA Region 8. In section 3.5 of the Thompson
Falls LMP, Montana states that it will continue to operate its
monitoring network to meet EPA requirements.
I. Does the plan meet the CAA requirements for contingency provisions
for maintenance plans?
Section 175A of the CAA states that a maintenance plan must include
contingency provisions, as necessary, to promptly correct any violation
of the NAAQS which may occur after redesignation of the area to
attainment. As explained in the LMP Option memo, these contingency
measures do not have to be fully adopted at the time of redesignation.
As noted above, CAA section 175A requirements are distinct from CAA
section 172(c)(9) contingency measures. Section 3.6 of the Thompson
Falls LMP describes a process and timeline to identify and evaluate
appropriate contingency measures in the event of a quality assured
violation of the PM<INF>10</INF> NAAQS. Upon notification of a
PM<INF>10</INF> exceedance in any of the three areas, the MDEQ and the
appropriate local government will develop contingency measures designed
to prevent or correct a violation of the PM<INF>10</INF> standard. This
process will be completed within twelve months of the exceedance
notification. Upon violating the PM<INF>10</INF> standard, the MDEQ and
local government will determine if the local contingency measures will
be adequate to prevent further exceedances or violations. If the
agencies determine that local measures will be inadequate, the MDEQ and
local government will adopt State-enforceable measures.
The current and proposed contingency provisions in the Thompson
Falls LMP meet the requirements for contingency provisions as outlined
in the LMP Option memo.
IV. Conformity and the LMP Option
Section 176(c) of the CAA requires the conformity of federal
actions to the air quality goals of an NAA or maintenance area. Such
federal actions include actions on transportation plans, programs and
projects developed, funded, or approved by federal agencies or by
recipients of federal funds, as well as more general actions receiving
federal assistance or approval. Conformity of these two types of
actions is known, respectively, as ``transportation conformity'' and
``general conformity.'' The purpose of conformity is to ensure that
such federal actions will not produce new air quality violations,
worsen existing violations, or delay timely attainment of the NAAQS.
The EPA's transportation and general conformity rules are found in 40
CFR part 93, subparts A and B, respectively.
The transportation conformity rule generally requires a
demonstration that emissions from the relevant projects of a
transportation plan and transportation improvement program covering a
designated area are consistent with the motor vehicle emissions budget
(MVEB or `budget') contained in the SIP or maintenance plan for that
area. The MVEB is the level of mobile source emissions of a pollutant
relied upon in the attainment or maintenance demonstration to attain or
maintain the NAAQS in the NAA or maintenance area.
Under the transportation conformity rule, designated areas meeting
the criteria for the LMP Option will not be required to satisfy the
rule's regional emissions analysis requirements (40 CFR 93.109(e)).
When the EPA approves an LMP, we are concluding that it is unreasonable
to expect that the qualifying area will experience sufficient growth
during the maintenance period that a violation of the PM<INF>10</INF>
NAAQS would result. Therefore, the EPA is concluding with an LMP
approval that the area's budget is essentially not constraining for the
duration of the maintenance period and a regional emissions analysis
will not be necessary to demonstrate conformity.
However, because LMP areas are still maintenance areas, approval of
a Thompson Falls LMP does not remove certain transportation conformity
rule requirements for transportation plans, programs, and projects. As
an isolated rural maintenance area, the Thompson Falls area will
generally be subject to the requirements of 40 CFR 93.109(g), as
modified by the requirements for LMP areas in 40 CFR 93.109(e).
Specifically, state transportation plans, transportation improvement
programs and transportation projects still must demonstrate that they
are fiscally constrained (30 CFR 93.108), are still subject to
consultation requirements (40 CFR 93.112), and projects must not
interfere with the implementation of any transportation control
measures from the applicable implementation plan (40 CFR 93.113).
Approval of the LMP option would have similar implications with
respect to general conformity. Federal actions subject to general
conformity in an LMP area will not be required to satisfy the budget
test requirement of the general conformity rule. Such federal actions
are presumed to conform under the LMP option as emissions budgets in
such areas are essentially not constraining for the duration of the
maintenance period.
V. Environmental Justice Concerns
To identify potential environmental burdens and susceptible
populations in the Thompson Falls NAA, EPA performed a screening-level
analysis using the EPA's EJSCREEN tool to evaluate environmental and
demographic indicators within the area. The tool outputs are contained
in the docket for this action. The results indicate that within the
Thompson Falls NAA, the EJ index for the National-Scale Air Toxics
Assessment (NATA) for diesel particulate matter is at the 81st
percentile compared to the rest of the State and results indicate a
low-income population of 58%, as compared to the State average of 34%
for Montana. These populations may be vulnerable and subject to
disproportionate impacts within the meaning of the executive orders
described above. Further, as the EJSCREEN analysis is a screening-level
assessment and not an in-depth review, it is possible that there are
other vulnerable groups within the Thompson Falls NAA.
As to all vulnerable groups within the Thompson Falls NAA, as
explained above, we believe that this action will be beneficial and
will tend to reduce impacts as this action, if finalized, addresses a
plan for continued attainment of the PM<INF>10</INF> NAAQS for the
Thompson Falls NAA. When the EPA establishes a new or revised NAAQS,
the CAA requires the EPA to designate all areas of the U.S. as either
nonattainment, attainment, or unclassifiable. If an area is designated
nonattainment for a NAAQS, the state must develop a plan outlining how
the area will attain and maintain the standard by reducing air
pollutant emissions. In this action we are proposing to approve the LMP
for the Thompson Falls NAA and the State's request to redesignate the
Thompson Falls NAA from nonattainment to attainment for the 1987 24-
hour PM<INF>10</INF> NAAQS. Approval of the LMP will contribute to the
ongoing protection of those residing, working, attending school, or
otherwise present in those areas, and we propose to determine that this
action, if finalized, will not have disproportionately high or adverse
[[Page 12912]]
human health or environmental effects on communities with environmental
justice concerns.
VI. Proposed Action
For the reasons explained in section III., we are proposing to
approve the LMP for the Thompson Falls NAA and the State's request to
redesignate the Thompson Falls NAA from nonattainment to attainment for
the 1987 24-hour PM<INF>10</INF> NAAQS. Additionally, the EPA is
proposing to determine that the Thompson Falls NAA has attained the
NAAQS for PM<INF>10</INF>. This determination is based upon monitored
air quality data for the PM<INF>10</INF> NAAQS during the years 2014-
2020. The EPA is proposing to approve the Thompson Falls LMP as meeting
the appropriate transportation conformity requirements found in 40 CFR
part 93, subpart A.
VII. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the Act and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely proposes to approve state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
<bullet> Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
<bullet> Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
<bullet> Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
<bullet> Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian tribe has
demonstrated that a tribe has jurisdiction. In those areas of Indian
country, the proposed rule does not have tribal implications and will
not impose substantial direct costs on tribal governments or preempt
tribal law as specified by Executive Order 13175 (65 FR 67249, November
9, 2000).
List of Subjects
40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Greenhouse gases, Incorporation by reference, Intergovernmental
relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting
and recordkeeping requirements, Sulfur oxides, Volatile organic
compounds.
40 CFR Part 81
Environmental protection, Air pollution control, National parks,
and Wilderness areas.
Authority: 42 U.S.C. 7401 et seq.
Dated: February 28, 2022.
KC Becker,
Regional Administrator, Region 8.
[FR Doc. 2022-04759 Filed 3-7-22; 8:45 am]
BILLING CODE 6560-50-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.