Document ID: EPA_FRDOC_0001-22946
Agency: epa
Document Type: Rule
Title: Adequacy Determinations: Montana; Missoula PM10 Limited Maintenance Plan for Transportation Conformity Purposes
Posted Date: 2018-09-27T04:00Z

[Federal Register Volume 83, Number 188 (Thursday, September 27, 2018)]
[Rules and Regulations]
[Pages 48715-48716]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-20446]

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ENVIRONMENTAL PROTECTION AGENCY

 40 CFR Part 52

[EPA-R08-OAR-2018-0608; FRL-9983-40--Region 8]

Adequacy Determination for the Missoula PM10 Limited Maintenance 
Plan for Transportation Conformity Purposes; State of Montana

AGENCY: Environmental Protection Agency (EPA).

ACTION: Adequacy determination.

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SUMMARY: In this announcement, the Environmental Protection Agency 
(EPA) is notifying the public that the EPA has found the Missoula 
PM10 National Ambient Air Quality Standard (NAAQS) Limited 
Maintenance Plan (LMP) adequate for transportation conformity purposes. 
As more fully explained in the Supplementary Information section of 
this notice, this finding will affect future transportation conformity 
determinations.

DATES: This finding is effective on October 12, 2018.

FOR FURTHER INFORMATION CONTACT: Tim Russ, Air Program, EPA, Region 8, 
Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129, (303) 
312-6479, or [email protected].

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,'' 
``us,'' or ``our'' is used, we mean the EPA.
    Transportation conformity is required by section 176(c) of the 
Clean Air Act to ensure that federally funded highway and transit 
projects are consistent with the air quality goals established by the 
state implementation plan (SIP). The EPA's conformity rule provisions 
at 40 CFR part 93, subpart A, establish the criteria and procedures for 
determining whether transportation plans, programs and projects conform 
to the SIP. Conformity to a SIP means that transportation activities 
will not produce new air quality violations, worsen existing 
violations, or delay timely attainment of the applicable NAAQS. \1\
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    \1\ The applicable PM10 NAAQS is found in 40 CFR part 
50, section 50.6: ``The level of the national primary and secondary 
24-hour ambient air quality standards for particulate matter is 150 
micrograms per cubic meter ([micro]g/m\3\), 24-hour average 
concentration. The standards are attained when the expected number 
of days per calendar year with a 24-hour average concentration above 
150 [micro]g/m\3\, as determined in accordance with appendix K to 
this part, is equal to or less than one.''
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    The criteria by which the EPA determines whether a SIP revision's 
LMP \2\ or motor vehicle emission budgets (MVEBs) are adequate for 
transportation conformity purposes are outlined at 40 CFR 93.118(e)(4), 
and the adequacy review process is described at 40 CFR 93.118(f)(1). We 
applied these criteria and followed this process in making the 
determinations announced in this notice.
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    \2\ On August 9, 2001, EPA issued a guidance memorandum titled 
``Limited Maintenance Plan Option for Moderate PM10 
Nonattainment Areas.'' https://www.epa.gov/sites/production/files/2016-06/documents/2001lmp-pm10.pdf.
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    This document is simply an announcement of findings that the EPA 
has already made, as described below.
    The State of Montana submitted the Missoula PM10 LMP \3\ 
on August 1, 2016. As part of our adequacy review, we announced receipt 
of the Missoula PM10 LMP and posted an announcement of 
availability on the EPA Office of Transportation and Air Quality's 
transportation conformity website https://www.epa.gov/state-and-local-transportation/adequacy-review-state-implementation-plan-sip-submissions-conformity. The EPA requested public comments by May 30, 
2018. We did not receive any comments. We sent a letter to the Montana 
Department of Environmental Quality on July 23, 2018, that stated that 
the submitted Missoula PM10 LMP was adequate for 
transportation conformity purposes.
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    \3\ Particulate matter less than or equal to 10 microns in 
diameter.
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    Following the effective date listed in the DATES section of this 
notice, the Missoula County-City Metropolitan Planning Organization, 
the Montana

[[Page 48716]]

Department of Transportation, and the U.S. Department of Transportation 
are required to use the provisions of the Missoula PM10 LMP 
for future transportation conformity determinations for projects in the 
Missoula PM10 nonattainment area. Please refer to 40 CFR 
81.327 for a description of the nonattainment area boundary. On the 
effective date of this adequacy determination, the previously-approved 
PM10 MVEB of 16,119 pounds per day of PM10\4\ for 
the Missoula PM10 NAAQS nonattainment area will no longer be 
applicable for transportation conformity purposes.
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    \4\ The PM10 MVEB was originally derived from the 
motor vehicle source category of the emissions inventory for the 
Missoula PM10 nonattainment area; see the EPA 's SIP 
approvals of December 13, 1994 (59 FR 64133) and August 30, 1995 (60 
FR 45051.)
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    Please note that our adequacy review of the LMP for transportation 
conformity is separate from our future rulemaking action on the 
Missoula PM10 redesignation request and LMP SIP revision and 
should not be used to prejudge our ultimate approval or disapproval of 
that SIP revision. Even if we find the Missoula PM10 LMP 
adequate for transportation conformity purposes now, we may later find 
it necessary to disapprove the SIP revision. Should this situation 
arise, we would revisit our adequacy finding.

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

    Dated: September 14, 2018.
Douglas Benevento,
Regional Administrator, EPA Region 8.
[FR Doc. 2018-20446 Filed 9-26-18; 8:45 am]
 BILLING CODE 6560-50-P