[Federal Register Volume 90, Number 160 (Thursday, August 21, 2025)]
[Rules and Regulations]
[Pages 40737-40738]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-15991]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R10-OAR-2025-0052; FRL-12541-01-R10]


Adequacy Status of the Klamath Falls, Oregon Submitted 2006 24-
Hour PM2.5 NAAQS Redesignation Request and Maintenance Plan Budgets for 
Transportation Conformity Purposes

AGENCY: Environmental Protection Agency (EPA).

ACTION: Determination of adequacy.

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SUMMARY: The EPA is notifying the public that we have found the motor 
vehicle emissions budgets for the Klamath Falls, Oregon 2006 24-hour 
fine particulate matter standard nonattainment area adequate for 
transportation conformity purposes. The budgets were submitted on 
August 20, 2024, as part of Oregon's Klamath Falls Redesignation 
Request and Maintenance

[[Page 40738]]

Plan. As a result of our finding, the Klamath Falls area must use these 
budgets for future transportation conformity determinations.

DATES: This finding is effective September 5, 2025.

FOR FURTHER INFORMATION CONTACT: Tess Bloom, 1200 6th Avenue, Suite 
155, Seattle, WA 98101; [email protected] or 206-553-6362.

SUPPLEMENTARY INFORMATION: Throughout this document, ``we'' and ``our'' 
refer to the EPA.
    This document is an announcement of a finding that we have already 
made. The EPA Region 10 sent a letter to the Oregon Department of 
Environmental Quality on April 25, 2025 stating that the 2017 and 2037 
fine particulate matter (PM2.5) and nitrogen oxides 
(NOX) motor vehicle emissions budgets in the Klamath Falls 
2006 24-hour PM2.5 national ambient air quality standards 
(NAAQS) nonattainment area, submitted as part of Oregon's August 20, 
2024, Redesignation Request and Maintenance Plan, are adequate. The 
finding is available in the docket for this action and at the EPA's 
conformity website: https://www.epa.gov/state-and-local-transportation/adequacy-review-state-implementation-plan-sip-submissions-conformity/. 
The adequate motor vehicle emissions budgets are provided in the 
following table:

Adequate Motor Vehicle Emissions Budgets for the 24-Hour PM2.5 NAAQS in the Klamath Falls Nonattainment Area for
                                           a Typical Season Day (TSD)
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                PM2.5 emissions (lbs/day)                                 NOX emissions (lbs/day)
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     2017 Attainment year           2037 Future year          2017 Attainment year          2037 Future year
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                     64                         77                          2,149                     1,448
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    The motor vehicle emissions budgets for the 2037 future year will 
be 77 and 1448 lbs/day for PM2.5 and NOX 
respectively. Oregon's Klamath Falls Redesignation Request and 
Maintenance Plan established a safety margin for the 2037 future year 
motor vehicle emissions budgets along with additional margin allocated 
from emissions reductions from woodstoves. The safety margin was 
applied to the 2037 future year motor vehicle emissions budgets to 
account for emissions from future transportation projects. The 
submission establishes that 411 woodstoves were removed after 2017 from 
the Klamath Falls nonattainment area which led to decreases in 
PM2.5 and NOX emissions. To provide an extra 
safety margin for mobile vehicle emissions, a portion of the emissions 
that would have occurred from the 411 woodstoves that were removed was 
allocated to the 2037 future year motor vehicle emissions budgets.
    Transportation conformity is required by Clean Air Act section 
176(c). The EPA's Transportation Conformity Rule requires that 
transportation plans, transportation improvement programs, and projects 
conform to state air quality implementation plans (SIPs) and 
establishes the criteria and procedures for determining whether or not 
they do.\1\ Conformity to a SIP means that transportation activities 
will not produce new air quality violations, worsen existing 
violations, or delay timely attainment of the NAAQS.
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    \1\ 40 CFR part 93, subpart A.
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    The criteria by which we determine whether a SIP's motor vehicle 
emission budgets are adequate for conformity purposes are outlined in 
40 CFR 93.118(e)(4). We've described our process for determining the 
adequacy of submitted SIP budgets in our July 1, 2004 (69 FR 40004) 
preamble starting at page 40038 and we used the information in these 
resources in making our adequacy determination. Please note that an 
adequacy review is separate from the EPA's completeness review and 
should not be used to prejudge the EPA's ultimate action on the 
redesignation request and maintenance plan.

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

    Dated: August 8, 2025.
Emma Pokon,
Regional Administrator, Region 10.
[FR Doc. 2025-15991 Filed 8-20-25; 8:45 am]
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