[Federal Register Volume 87, Number 87 (Thursday, May 5, 2022)]
[Proposed Rules]
[Pages 26710-26722]
[FR Doc No: 2022-09256]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R10-OAR-2022-0124; FRL-9488-01-R10]

Air Plan Approval; OR; Oakridge PM2.5 Redesignation to Attainment
and Maintenance Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) proposes to
redesignate the Oakridge, Oregon nonattainment area (Oakridge NAA or
Oakridge area) to attainment for the 2006 24-hour fine particulate
matter (PM2.5) National Ambient Air Quality Standard
(NAAQS). EPA also proposes to approve a maintenance plan for the area
demonstrating continued compliance with the PM2.5 NAAQS
through 2035, which the Lane Regional Air Protection Agency (LRAPA)
developed in coordination with the Oregon Department of Environmental
Quality (ODEQ), for inclusion into the Oregon State Implementation Plan
(SIP). The Oakridge PM2.5 maintenance plan was submitted to
EPA by ODEQ along with the redesignation request on January 13, 2022.
Additionally, EPA proposes to approve the motor vehicle emissions
budgets included in the Oakridge PM2.5 maintenance plan and
inform the public that we are starting the adequacy process for the
proposed motor vehicle emissions budgets, including a public comment
period. EPA also proposes to approve additional control measures
because incorporation of these measures will strengthen the Oregon SIP
and ensure PM2.5 emissions reductions in the Oakridge area.
Finally, EPA proposes to take final agency action on an exceptional
events request submitted by ODEQ on July 22, 2021 and concurred on by
EPA on April 1, 2022. EPA proposes these actions pursuant to the Clean
Air Act (CAA or the Act).

DATES: Comments must be received on or before June 6, 2022.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2022-0124, at https://www.regulations.gov. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from Regulations.gov. EPA may publish any comment
received to its public docket. Do not electronically submit any
information you consider to be Confidential Business Information (CBI)
or other information the disclosure of which 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. EPA will
generally not consider comments or 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 https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Christi Duboiski (15-H13), EPA Region
10, 1200 Sixth Avenue (Suite 155), Seattle WA 98101, at<PHONE_NUMBER>,
or [email protected].

SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,'' or
``our'' is used, it refers to EPA.

Table of Contents

I. Background
II. Clean Air Act Requirements for Redesignation to Attainment
III. EPA's Analysis of Oregon's Submittal
    A. Attainment Determination
    B. Applicable Requirements Under Section 110 and Part D of the
CAA
    1. CAA Section 110 General SIP Requirements
    2. Part D of Title I Requirements
    3. Fully Approved SIP Under CAA Section 110(k)
    C. Improvement in Air Quality Due to Permanent and Enforceable
Measures
    D. Fully Approved Maintenance Plan
    1. Attainment Inventory
    2. Maintenance Demonstration
    3. Monitoring Network and Verification of Continued Attainment
    4. Contingency Plan
    E. Transportation Conformity and Motor Vehicle Emissions Budgets
    F. State Rule Changes To Reflect the Redesignation
IV. Proposed Action
V. Incorporation by Reference
VI. Statutory and Executive Orders Review

I. Background

    On October 17, 2006, EPA revised the level of the 24-hour
PM2.5 NAAQS, lowering the primary and secondary standards
from the 1997 standard of 65 micrograms per cubic meter ([micro]g/m\3\)
to 35 [micro]g/m\3\ (71 FR 61143). On November 13, 2009, EPA designated
a portion of Lane County, Oregon nonattainment for the 2006 24-hour
PM2.5 NAAQS (74 FR 58688). This nonattainment area is
referred to as the Oakridge, Oregon PM2.5 NAA (Oakridge NAA
or Oakridge area).
    The Oakridge NAA boundary is a rectangular area that includes the
City of Oakridge and the small town of Westfir. The City of Oakridge is
situated in a valley where the middle fork of the Willamette River
flows east to west, and mountains rise on the north and south sides.
Westfir is a very small isolated rural mountain community also located
in a valley along the north fork of the Willamette River about 1-mile
NW of Oakridge. It is surrounded by the same high mountains. This
topography can act as a barrier to air movement in the Oakridge NAA
during temperature inversions, which occur in the winter months and are
often the cause of elevated concentrations of PM2.5.
Additional information pertaining to the specific boundary for the
Oakridge NAA can be found in the November 13, 2009, final designations
action for the 2006 24-hour PM2.5 NAAQS (74 FR 58688).
    The nonattainment designation of the Oakridge NAA required Oregon
to prepare and submit an attainment plan to meet statutory and
regulatory requirements.\1\ ODEQ submitted this attainment plan to EPA
on December 12, 2012 (2012 attainment plan). EPA approved the
description of the Oakridge NAA and the baseline emissions inventory
and disapproved everything else submitted in the attainment plan on
October 21, 2016 (81 FR 72714). ODEQ submitted a supplement to the
attainment plan on January 20, 2017 (2017 Oakridge Update). On February
8, 2018, EPA approved the 2017 Oakridge Update including the attainment
year emission inventory, the control measures in the attainment plan as
meeting reasonably available control measures/technology (RACM/RACT),
the attainment demonstration, the motor vehicle emissions budgets
(MVEBs) for PM2.5, the demonstration of reasonable progress,
the quantitative milestones and contingency measures (83 FR 5537).
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    \1\ See part D of title I of the Clean Air Act and EPA's Fine
Particulate Matter National Ambient Air Quality Standards: State
Implementation Plan Requirements (72 FR 20586, April 25, 2007).
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    In addition, on July 18, 2016, EPA granted a one-year extension,
under CAA section 188(d), to the December 31, 2015, Moderate attainment
date for the 2006 24-hour PM2.5 Oakridge NAA (81 FR 46612).
On February 8, 2018, EPA finalized a determination that the Oakridge
NAA had attained the 2006 24-hour PM2.5 NAAQS (Determination
of Attainment) by the December 31, 2016, attainment date (83 FR 5537).

II. Clean Air Act Requirements for Redesignation to Attainment

    The CAA provides the requirements for redesignating a nonattainment
area to attainment. Specifically, section 107(d)(3)(E) of the CAA,
allows for redesignation provided that: (1) EPA determines that the
area has attained the applicable NAAQS; (2) EPA has fully approved the
applicable implementation plan for the area under section 110(k) of the
CAA; (3) EPA determines that the improvement in air quality is due to
permanent and enforceable reductions in emissions resulting from
implementation of the applicable SIP and applicable Federal air
pollutant control regulations and other permanent and enforceable
reductions; (4) EPA has fully approved a maintenance plan for the area
as meeting the requirements of section 175A of the CAA; and (5) the
state has met all requirements applicable to the area under section 110
and part D of the CAA. In this proposed action, EPA will review CAA
section 107(d)(3)(E) requirements (2) and (5) together as part of our
evaluation of Oregon's redesignation request.
    EPA has provided guidance on redesignations in the ``General
Preamble,'' \2\ and has provided further guidance on processing
redesignation requests in the following documents: (1) ``Procedures for
Processing Requests to Redesignate Areas to Attainment,'' Memorandum
from John Calcagni, Director, Air Quality Management Division,
September 4, 1992 (hereafter the ``Calcagni Memo''); (2) ``State
Implementation Plan (SIP) Actions Submitted in Response to Clean Air
Act (CAA) Deadlines,'' Memorandum from John Calcagni, Director, Air
Quality Management Division, October 28, 1992; and (3) ``Part D New
Source Review (part D NSR) Requirements for Areas Requesting
Redesignation to Attainment,'' Memorandum from Mary D. Nichols,
Assistant Administrator for Air and Radiation, October 14, 1994. These
documents are included in the Docket for this proposed action.
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    \2\ See ``State Implementation Plans; General Preamble for the
Implementation of Title I of the Clean Air Act Amendments of 1990,''
57 FR 13498, April 16, 1992.
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III. EPA's Analysis of Oregon's Submittal

    EPA proposes to redesignate the Oakridge NAA to attainment for the
2006 24-hour PM2.5 NAAQS and proposes to approve into the
Oregon SIP the associated Oakridge PM2.5 maintenance plan.
EPA's proposed approval of the redesignation request and maintenance
plan is based upon EPA's determination that the area continues to
attain the 2006 24-hour PM2.5 NAAQS and that all other
redesignation criteria have been met for the area. Sections III.A
through D of this document describe how Oregon's January 13, 2022,
submittal satisfies the requirements of section 107(d)(3)(E) of the CAA
for the 2006 24-hour PM2.5 standard.\3\
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    \3\ We note that the January 13, 2022 submittal also includes
the Oakridge PM10 redesignation and maintenance plan and
revisions to LRAPA's Title 29 rules, which EPA will address in a
separate action.
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    Oregon's submittal also addresses transportation MVEBs and
emissions from wildfire-influenced PM2.5 concentrations
recorded in the Oakridge NAA in 2020. EPA proposes to approve the MVEBs
and proposes to approve the exclusion of ambient air quality monitoring
data associated with the wildfire-influenced exceptional events that
affected this data in September of 2020 for the purposes of showing
continued attainment of the NAAQS.

A. Attainment Determination

    To redesignate an area from nonattainment to attainment, the CAA
requires EPA to determine that the area has attained the applicable
NAAQS (CAA section 107(d)(3)(E)(i)). EPA determines whether an area has
attained the 2006 24-hour PM2.5 NAAQS based upon measured
air quality levels at each eligible monitoring site to produce a design
value equal to or below 35 [micro]g/m\3\.\4\ A state must demonstrate
that an area has attained the 2006 24-hour PM2.5 NAAQS
through submittal of ambient air quality data from an ambient air
monitoring network representing expected maximum PM2.5
concentrations. The data must be quality-assured, quality-controlled
and certified in EPA's Air Quality System (AQS) and it must show that
the three-year average of valid PM2.5 98th percentile mass
concentrations is equal to or below the 2006 24-hour PM2.5
NAAQS (35 [micro]g/m\3\), pursuant to 40 CFR 50.13. In making this
showing, three years of complete air quality data must be used.
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    \4\ See 40 CFR part 50 and 40 CFR part 50, appendix N.
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The Exceptional Event Rule
    Congress has recognized that it may not be appropriate for EPA to
use certain monitoring data collected by the ambient air quality
monitoring network and maintained in EPA's AQS database \5\ in certain
regulatory determinations. Thus, in 2005, Congress provided the
statutory authority for the exclusion of data influenced by
``exceptional events'' meeting specific criteria by adding section
319(b) to the CAA.\6\ To implement this 2005 CAA amendment, EPA
promulgated the 2007 Exceptional Events Rule.\7\ The 2007 Exceptional
Events Rule created a regulatory process codified at 40 CFR parts 50
and 51 (sections 50.1, 50.14 and 51.930). These regulatory sections,
which superseded EPA's previous guidance on handling data influenced by
events, contain definitions, procedural requirements, requirements for
air agency demonstrations, criteria for EPA's approval of the exclusion
of event-affected air quality data from the data set used for
regulatory decisions, and requirements for air agencies to take
appropriate and reasonable actions to protect public health from
exceedances or violations of the NAAQS. In 2016, EPA promulgated a
comprehensive revision to the 2007 Exceptional Events Rule.\8\ The 2016
Exceptions Events Rule revision included the requirement that, if a
state demonstrates that emissions from a wildfire smoke event caused a
specific air pollution concentration in excess of the NAAQS at a
particular air quality monitoring location and otherwise satisfies the
requirements of 40 CFR 50.14, EPA must exclude that data from use in
determinations of exceedances and violations.\9\
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    \5\ AQS is EPA's official repository of ambient air data.
    \6\ Under CAA section 319(b), an exceptional event means an
event that (i) affects air quality; (ii) is not reasonably
controllable or preventable; (iii) is an event caused by human
activity that is unlikely to recur at a particular location or a
natural event; and (iv) is determined by EPA under the process
established in regulations promulgated by EPA in accordance with
section 319(b)(2) to be an exceptional event. For the purposes of
section 319(b), an exceptional event does not include (i) stagnation
of air masses or meteorological inversions; (ii) a meteorological
event involving high temperatures or lack of precipitation; or (iii)
air pollution relating to source noncompliance.
    \7\ 72 FR 13560, March 22, 2007.
    \8\ 81 FR 68216 (October 3, 2016). We refer herein to the 2016
revision as the ``Exceptional Events Rule.''
    \9\ 40 CFR 50.14(b)(4).
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The Oakridge NAA Exceptional Event Demonstrations and Concurrences
    The CAA allows for the exclusion of air quality monitoring data
from design value calculations when there are NAAQS exceedances caused
by events, such as wildfires, that meet the criteria for an exceptional
event identified in EPA's Exceptional Events Rule at 40 CFR 50.1, 50.14
and 51.930. For the purposes of this proposed action, on July 22, 2021,
ODEQ submitted an exceptional events demonstration to show that
PM2.5 concentrations recorded at the Oakridge Willamette
Center monitor from September 11, 2020 through September 16, 2020 were
influenced by wildfires. EPA concurred on this request on April 1,
2022.
    EPA found that Oregon's demonstration met the Exceptional Events
Rule criteria and determined that these wildfire events had regulatory
significance for purposes of calculating the area's most recent design
value to demonstrate the area continues to attain the standard in order
to redesignate the area to attainment for the PM2.5 NAAQS.
As such, EPA proposes to take final regulatory action on the concurred
dates, as detailed in the docket, as exceptional events to be removed
from the data set used for regulatory purposes. For this proposed
action, EPA will rely on the calculated values that exclude the event-
influenced data for the purpose of demonstrating continued attainment
of the 2006 PM2.5 NAAQS. Further details on Oregon's
analyses and EPA's concurrences can be found in the docket for this
regulatory action.
    While EPA may agree with Oregon's request to exclude event-
influenced air quality monitoring data from regulatory decisions, these
regulatory actions require EPA to provide an opportunity for public
comment on the claimed exceptional events and all supporting data prior
to EPA taking final agency action. This proposed action provides the
public with an opportunity to comment on the claimed exceptional
events, all supporting documents and EPA's proposed concurrence with
Oregon's request.
Evaluation of Continued Attainment
    As previously noted, on February 8, 2018, EPA finalized a
Determination of Attainment for the Oakridge NAA based upon quality-
assured and certified ambient air quality monitoring data for the 2014-
2016 design value period (83 FR 5537). The monitoring data used as the
basis for the Determination of Attainment under CAA section 188(b)(2)
is provided in Table 1 of this document.

                                                Table 1--Oakridge Area PM2.5 2016 Attaining Design Value
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                                                                                98th percentile value ([micro]g/m\3\)
                              Monitor                                  AQS site ID   ---------------------------------------------------    2014-2016
                                                                                2014             2015             2016         design value
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Willamette Center..................................................       410392013             41.1             28.9             21.7               31
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    For this proposed action, EPA reviewed the subsequent
PM2.5 ambient air monitoring data in the Oakridge area for
the monitoring design value periods of 2017-2020. Consistent with the
requirements at 40 CFR part 50, this ambient monitoring data in EPA's
AQS has been quality-assured, quality-controlled and certified by ODEQ.
As Table 2 indicates, the Oakridge NAA has continued to attain the 2006
24-hour PM2.5 NAAQS since EPA issued its

February 8, 2018, Determination of Attainment for the area based on the
2016 attaining design value shown in Table 1 of this document.

                                                 Table 2--Oakridge Area PM2.5 Design Values (2017-2020)
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                                                                98th percentile values ([micro]g/m\3\)            2017-2020 design values \a\ ([micro]g/
                                                     ------------------------------------------------------------                  m\3\)
                       Monitor                                                                                ---------------------------------------
                                                        2015      2016      2017      2018      2019      2020      2017      2018      2019      2020
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Willamette Center...................................     28.9      21.7      35.7      33.2      36.7      32.2        29        30        35        34
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\a\ EPA concurred on the removal of exceptional events data for 2017 in a letter dated 5/21/2020 and exceptional events data for 2020 in a letter dated
  4/01/2022. The specified data was excluded from AQS.

    EPA's review of the monitoring data supports the previous
determination that the area has attained the standard and therefore EPA
finds it is appropriate to conclude the area has continued to attain
the NAAQS through 2020, based on uninterrupted attaining design values
at the Willamette Center monitor.

B. Applicable Requirements Under Section 110 and Part D of the CAA

    Section 107(d)(3)(E)(ii) and (v) of the CAA states that for an area
to be redesignated to attainment, it must be determined that the
Administrator has fully approved the applicable implementation plan for
the area under CAA section 110(k) and all the requirements applicable
to the Area under section 110 of the CAA (general SIP requirements) and
part D of Title I of the CAA (SIP requirements for nonattainment areas)
must be met. We interpret this to mean that, for a redesignation
request to be approved, the state must have met all requirements that
applied to the subject area prior to, or at the time of, submitting a
complete redesignation request. EPA may rely on prior SIP approvals in
approving a redesignation request \10\ as well as any additional
measure it may approve in conjunction with a redesignation action.
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    \10\ Calcagni Memo, 3; Wall v. EPA, 265 F.3d 426, 438 (6th Cir.
2001); and Southwestern Pennsylvania Growth Alliance v. Browner, 144
F.3d 984, 989-990 (6th Cir. 1998).
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1. CAA Section 110 General SIP Requirements
    Section 110(a)(2) of Title I of the CAA delineates the general
requirements for a SIP, which include enforceable emissions limitations
and other control measures, means or techniques, provisions for the
establishment and operation of appropriate devices necessary to collect
data on ambient air quality, and programs to enforce the limitations.
The general SIP elements and requirements set forth in CAA section
110(a)(2) include, but are not limited to the following:
     Submittal of a SIP that has been adopted by the state
after reasonable public notice and hearing;
     Provisions for establishment and operation of appropriate
procedures needed to monitor ambient air quality;
     Implementation of a source permit program; provisions for
the implementation of part C requirements (PSD);
     Provisions for the implementation of part D requirements
for NSR permit programs;
     Provisions for air pollution modeling; and
     Provisions for public and local agency participation in
planning and emission control rule development.\11\
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    \11\ See the General Preamble for further explanation of these
requirements. 57 FR 13498 (April 16, 1992).
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    We note that SIPs must be fully approved only with respect to
applicable requirements for purposes of redesignation in accordance
with section 107(d)(3)(E)(ii). Similarly, EPA believes that the other
CAA section 110(a)(2) (and part D) requirements that are not connected
with nonattainment plan submittals and not linked with an area's
attainment status are not applicable requirements for purposes of
redesignation because the area will still be subject to these
requirements after it is redesignated. EPA considers the CAA section
110(a)(2) (and part D) requirements that relate to a particular
nonattainment area's designation and classification as the relevant
measures to evaluate in reviewing a redesignation request. This
approach is consistent with EPA's existing policy on applicability of
the conformity SIP requirement for redesignations.\12\
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    \12\ See 75 FR 36023, 36026 (June 24, 2010) and citations
within.
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    EPA has reviewed the Oregon SIP and concludes that it meets the
general SIP requirements under Section 110(a)(2) of the CAA to the
extent they are applicable for the purposes of redesignation.\13\ EPA
has previously approved provisions of Oregon's SIP as demonstrating
compliance with the CAA section 110(a)(2) requirements for the 2006
PM2.5 NAAQS (78 FR 46514, August 1, 2013, and 80 FR 2313,
January 15, 2015). These requirements are, however, statewide
requirements that are not linked to the PM2.5 nonattainment
status of the Oakridge NAA. In addition, there are no outstanding or
disapproved applicable SIP submittals with respect to the Oakridge
portion of the SIP that would prevent redesignation of the Oakridge NAA
for the PM2.5 NAAQS. Therefore, we conclude that ODEQ and
LRAPA have met all general SIP requirements for the Oakridge NAA that
are applicable for purposes of redesignating the area to attainment of
the PM2.5.
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    \13\ The LRAPA portion of the federally-approved Oregon SIP can
be viewed at https://www.epa.gov/sips-or/epa-approved-regulations-oregon-sip.
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2. Part D of Title I Requirements
    Part D of Title I of the CAA sets forth the basic nonattainment
plan requirements applicable to all nonattainment areas at subpart 1
(CAA sections 172-176) and requirements specific to PM10 and
PM2.5 areas at subpart 4 (CAA section 189). On August 24,
2016, EPA promulgated the Fine Particulate Matter National Ambient Air
Quality Standards; State Implementation Plan Requirements rule.\14\
This rule implements the requirements of part D of Title I of the CAA
for areas designated nonattainment for any PM2.5 NAAQS.
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    \14\ See 81 FR 58010 (August 24, 2016). Codified at 40 CFR part
51, subpart Z.
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    In accordance with 40 CFR 51.1015, upon a determination by EPA that
a Moderate PM2.5 nonattainment area has attained the
PM2.5 NAAQS, the requirements for the state to submit an
attainment demonstration, provisions demonstrating that RACM (including
RACT for stationary sources) shall be implemented no later than 4 years
following the date of designation of the area, Reasonable Further
Progress (RFP) plan, quantitative milestones (QM) and reports, and
contingency measures for the area shall be suspended until such time
as: (1) The area is redesignated to attainment, after which such
requirements are permanently discharged; or, (2) EPA determines that
the area has re-violated the PM2.5 NAAQS.
    Those states containing Moderate PM2.5 NAAs were
required to submit a

SIP by December 31, 2014, which demonstrated attainment of the
PM2.5 NAAQS by December 31, 2015.\15\ Pursuant to CAA
section 188(d) and 40 CFR 51.1005(a), on July 18, 2016, EPA extended
the attainment date for the Oakridge NAA from December 31, 2015 to
December 31, 2016 (81 FR 46612). As stated in the ``Background''
section of this document, EPA has approved all attainment plan elements
for the Oakridge NAA. Specifically, EPA approved the following elements
of the Oakridge attainment plan: Base year emissions inventory (October
21, 2016, 81 FR 72714); control measures, RACM/RACT level emission
controls, attainment demonstration, contingency measures, RFP plan, QM
and MVEB (February 8, 2018, 83 FR 5537); and nonattainment NSR (October
5, 2018, 83 FR 50274). In addition, Pursuant to 40 CFR 51.1015(a), on
February 8, 2018, EPA determined that the Oakridge NAA achieved a Clean
Data Determination (CDD) in accordance with EPA's clean data policy and
that the Oakridge area attained the 2006 24-hour PM2.5 NAAQS
by the December 31, 2016, attainment date (83 FR 5537).
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    \15\ See Section 188(c)(1) of the CAA, 42 U.S.C. 7513(c)(1), and
40 CFR 51.1004(a)(1). See also Identification of Nonattainment
Classification and Deadlines for Submission of State Implementation
Plan (SIP) Provisions for the 1997 Fine Particle (PM2.5)
National Ambient Air Quality Standard (NAAQS) and 2006
PM2.5 NAAQS (June 2, 2014), 79 FR 31566, 31567-68.
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    Determinations of attainment do not relieve states from submitting
and EPA from approving certain part D planning requirements for the
2006 PM2.5 NAAQS. CAA section 172(c)(3) requires submittals
and approval of a comprehensive, accurate and current inventory of
actual emissions. For purposes of the PM2.5 NAAQS, this
emissions inventory should address not only direct emissions of
PM2.5, but also emissions of all precursors to
PM2.5 formation, i.e., SO2, NOX, VOC,
and ammonia. As previously discussed, EPA determined that Oregon met
the CAA section 172(c)(3) comprehensive emissions inventory requirement
in a final rulemaking on October 21, 2016 (81 FR 72714).
    CAA section 172(c)(4) requires the identification and
quantification of allowable emissions for major new or modified
stationary sources in an area, and CAA section 172(c)(5) requires
source permits for the construction and operation of new or modified
major stationary sources anywhere in the nonattainment area. EPA first
approved the requirements of the part D, subpart 1 NSR permit program
for LRAPA on December 27, 2011 (76 FR 80747, 80748). Subsequently,
LRAPA revised its rules to meet additional part D, subpart 4 NSR
requirements promulgated by EPA (81 FR 58010, August 24, 2016) and to
align with the ODEQ's rules.\16\ EPA approved LRAPA's rules on October
5, 2018 (83 FR 50274).
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    \16\ See 40 CFR 51.160, 51.161, 51.165, and 51.166. See also
EPA's proposed approval of Oregon nonattainment NSR program (March
22, 2017, 82 FR 14654, 14663) and EPA's final approval (October 11,
2017, 82 FR 47122).
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    Once the Oakridge NAA is redesignated to attainment, the prevention
of significant deterioration (PSD) requirements of part C of the CAA
will apply. LRAPA's PSD regulations are codified in LRAPA's rules at
Title 38 (New Source Review) in conjunction with other provisions
including but not limited to LRAPA's rules in Titles 12, 31, 34, 35,
40, 42, and 50. We most recently approved revisions to LRAPA's PSD
program on October 5, 2018 (83 FR 50274). EPA finds that LRAPA's PSD
provisions meet all applicable Federal requirements for any area
designated unclassifiable or attainment, and these provisions will
become fully effective in the Oakridge NAA upon redesignation of the
area to attainment.
    CAA section 172(c)(7) requires the SIP to meet the applicable
provisions of CAA section 110(a)(2). As noted above, we find that the
Oregon SIP meets the CAA section 110(a)(2) applicable requirements. For
purposes of redesignation to attainment for the 2006 24-hour
PM2.5 NAAQS, EPA proposes to find that LRAPA has met all the
applicable SIP requirements under part D of Title I of the CAA in
accordance with section 107(d)(3)(E)(v) of the CAA.
3. Fully Approved SIP Under CAA Section 110(k)
    Section 110(k) of the CAA sets out provisions governing EPA's
review of SIP submittals. In order for an area to qualify for
redesignation, the SIP for the area must be fully approved under
section 110(k) of the CAA. As discussed in Sections III.B.1 and III.B.2
of this document, for purposes of redesignation to attainment for the
2006 24-hour PM2.5 NAAQS, EPA has fully approved all
applicable requirements of Oregon's SIP for the Oakridge area in
accordance with CAA section 110(k). Therefore, the criterion for
redesignation, set forth at CAA section 107(d)(3)(E)(ii), is satisfied.

C. Improvement in Air Quality Due to Permanent and Enforceable Measures

    Section 107(d)(3)(E)(iii) of the CAA provides that for an area to
be redesignated to attainment, the Administrator must determine that
the improvement in air quality is due to permanent and enforceable
reductions in emissions resulting from implementation of the applicable
implementation plan, implementation of applicable Federal air pollutant
control regulations, and other permanent and enforceable reductions.
    The main source of PM2.5 emissions in the Oakridge NAA
during the winter season days--when concentrations of emissions
accumulate leading to exceedances of the 2006 24-hour PM2.5
NAAQS--is wood combustion in woodstoves, fireplaces and pellet stoves.
Therefore, LRAPA identified strategies in the 2017 Oakridge Update that
focused primarily on residential wood combustion (RWC) emission
reductions such as Oakridge's mandatory curtailment program and the
woodstove change-out programs. EPA approved these control measures as
RACM into the Oregon SIP on February 8, 2018 (83 FR 5537), making them
federally enforceable.
    The 2017 Oakridge Update includes specific sections of the City of
Oakridge's RWC Ordinance 920 (RWC Ordinance) as it applies within the
City of Oakridge. The SIP-approved provisions of the RWC Ordinance
include a mandatory curtailment program, which has been important in
helping this area reach attainment of the NAAQS. Modeling showed that
the curtailment program would result in a calculated PM2.5
emissions reduction of 7.1 [micro]g/m\3\ in the Oakridge NAA, the
largest of all the control measures included in the plan.
    The provisions of the RWC Ordinance that EPA approved into the SIP
also prohibit the burning of any fuel other than ``seasoned wood,''
which is defined as any species of wood that has been sufficiently
dried to contain 20 percent or less moisture by weight. EPA also
approved into the SIP provisions of the RWC Ordinance that specifically
prohibit the burning of specified materials such as plastic, rubber
products, petroleum-treated materials and other materials which
normally emit dense smoke, noxious odors, or hazardous air contaminants
in a solid fuel burning device.
    LRAPA also quantified the emission reduction benefits from
woodstove change-outs that were conducted between 2009 and 2012,
replacing 90 uncertified woodstoves in the Oakridge NAA. These
woodstove change-out programs achieved permanent and enforceable
emissions reductions because the higher-emitting woodstoves were
removed and required to be destroyed. In addition, the Oregon Heat
Smart Program, a statewide mandate approved by EPA on October 11, 2017

(82 FR 47122), and the RWC Ordinance prohibit the installation of non-
EPA certified devices and ban the sale or installation of non-EPA
certified devices in new or existing buildings. The collective
permanent and enforceable PM2.5 reductions for these
changeout programs in the Oakridge NAA were calculated to be 2.6
[micro]g/m\3\.
    LRAPA also referenced Federal transportation and fuel-related
control measures to reduce mobile source emissions, including the
``Tier 3 Motor Vehicle Emission and Fuel Standards Rule'' as permanent
and enforceable reductions leading to improvement in air quality (1.3
[micro]g/m\3\ reduction on a worst-case winter day) and ultimately to
attainment, in the Oakridge NAA. See 79 FR 23414 (April 28, 2014).
    The RWC Ordinance 920--Section Two(3) was initially submitted in
the 2017 Oakridge Update, but was ultimately not approved as part of
the 2017 Oakridge Update. The RWC Ordinance 920--Section Two(3) was
later resubmitted as part of the Oakridge PM2.5 maintenance
plan. The Lane County Code--Restriction on Use of Solid Fuel Space
Heating Devices (9.120-9.140) (Lane County Code) is also included in
the Oakridge PM2.5 maintenance plan submittal and applies
more broadly to the Oakridge Urban Growth Boundary. Both establish
additional permanent and enforceable control measures on residential
heating devices for the purpose of ensuring continued attainment in the
Oakridge NAA. The Lane County Code, like the previously approved
provisions of the RWC Ordinance, includes a curtailment program in the
Oakridge urban growth boundary, prohibiting the burning of any fuel
other than seasoned wood and other specified prohibited materials in
solid-fuel heating devices. These restrictions on materials that may be
burned limit PM2.5 emissions from woodstoves and fireplaces
on a continuous basis.
    Section Two(3) of the RWC Ordinance, which EPA did not act on as
part of the 2017 Oakridge Update, prohibits emissions from solid-fuel
heating devices with an opacity greater than 20%. The Lane County Code,
included in the Oakridge PM2.5 maintenance plan submittal,
also includes this restriction. These 20% opacity limits provide a
visual indicator for the proper operation of a solid-fuel heating
device, including the use of properly seasoned wood. The opacity limits
apply at all times under each rule, except during a ten-minute startup
period in any 4-hour period. During these startup periods, however,
solid-fuel heating devices are subject to other restrictions, namely a
fuel-content restriction that limits the moisture content of burned
wood and restrictions on the type of fuel burned, such as a prohibition
on burning any material that normally emits dense smoke, noxious odors,
or hazardous air pollutants. EPA also notes that the current,
federally-approved SIP includes no opacity limit for residential wood
burning, meaning that approval of this provision will result in a net
air quality benefit over the status quo.
    EPA has longstanding guidance that provides recommendations to
states concerning the development of alternative emission limitations
applicable during startup and shutdown. In a June 12, 2015, Federal
Register notice (80 FR 33840) (the ``2015 SSM policy''), EPA
recommended States consider seven criteria when developing alternative
emission limitations to replace automatic or discretionary exemptions
from otherwise applicable SIP requirements. These recommended criteria
assure the alternative emission limitations meet basic CAA
requirements.
    As discussed above, although the 20% opacity limit does not apply
during short periods of startup and refueling, owners and operators of
solid-fuel heating devices are subject to alternative fuel-content
limitations during these periods. EPA evaluated whether these
alternative requirements are consistent with the Agency's 2015 SSM
policy, including the seven criteria recommended therein. For the
reasons explained below, EPA finds that the opacity limit and other
restrictions on fuel are consistent with the recommended criteria set
forth in that policy and proposes to approve these provisions into the
Oregon SIP as part of this action.
    First, the opacity limit for residential woodstoves and similar
devices and the alternative restrictions on fuel content--which are
codified in both the Lane County Code, Section 9.135, and Oakridge
Ordinance No. 920, Section Two(3)--apply to a narrow subset of source
categories: Solid-fuel heating devices. Second, application of the 20%
opacity limit to startup and refueling periods would be technically
infeasible because lower temperatures during these periods result in
less complete combustion and, therefore, higher opacity. Third, for
this source category, EPA believes the startup period is minimized to
the greatest extent practicable. The startup period is limited to just
ten minutes in every 4-hour period to account for starting the solid
fuel burning device and refueling. This ten minute period represents
the minimum time necessary to adequately start a fire in a solid fuel
burning device. Furthermore, the startup period is limited to once
every four hours, which reasonably reflects the amount of time before a
residential fire needs additional fuel.
    With respect to the fourth factor, EPA believes that LRAPA's
proposed control strategy, specifically the episodic curtailment
program, would effectively prohibit the use of solid fuel burning
devices at most locations \17\--and thus largely prohibit use of the
startup exemption--during worst-case air quality scenarios.
---------------------------------------------------------------------------

    \17\ Exemptions from the use of woodstoves and similar devices
during curtailment periods are available on an annual basis if the
woodstove or similar device is the sole source of heat in the
residence and/or due to economic need based on specified criteria.
---------------------------------------------------------------------------

    Fifth, the limits on fuel content and type are designed to ensure
that all possible steps are taken to minimize the impact of emissions
during the startup period. With respect to this factor, EPA also notes
that the emission source at issue here is subject to curtailment
requirements during periods of high PM2.5 ambient air
concentration, which would further minimize potential air quality
impacts from reliance on the alternative emission limits when the
opacity limit does not apply.
    Similarly, EPA believes the sixth factor--that the alternative
emission limit requires operation of the facility in a manner
consistent with good practices for minimizing emissions and best-
efforts regarding planning, design, and operating procedures--supports
approval of the State's chosen control strategy. As noted above, limits
on fuel content and type used in conjunction with emission curtailment
during air quality episodes represent the best practices available in
this context.
    With respect to the last criterion for alternative emission limits,
Oregon has not included a requirement that affected sources document
startup periods using properly signed, contemporaneous logs or other
evidence. Given that the rule at issue here generally applies to
individual homeowners, rather than industrial sources accustomed to
complying with such recordkeeping requirements, EPA believes a
recordkeeping requirement would impose an unreasonable burden on both
regulators implementing the rule and the regulated community, with
virtually no enforcement benefit justifying the burden.
    For all of these reasons, EPA proposes to approve (and incorporate
by reference) the Oakridge RWC Ordinance 920--Section Two(3) and the
Lane

County Code as they apply to the Oakridge area because they are
permanent and enforceable SIP-strengthening measures that contribute to
continued maintenance of the 2006 PM2.5 24-hour NAAQS. Both
provisions include limits on emissions that apply during all modes of
source operation and impose continuous emission controls on solid-fuel
heating devices consistent with the requirements of the CAA applicable
to SIP provisions. In addition, they support the maintenance and
continued attainment of the PM2.5 NAAQS in the Oakridge
area.
    Based on the foregoing evaluation of the Oakridge PM2.5
control measures, EPA proposes to determine that the improvement in air
quality is reasonably attributable to permanent and enforceable
reductions in emissions resulting from implementation of the applicable
implementation plan, implementation of applicable Federal air pollutant
control regulations, and other permanent and enforceable reductions.

D. Fully Approved Maintenance Plan

    CAA section 107(d)(3)(E)(iv) requires that, for a nonattainment
area to be redesignated to attainment, EPA must fully approve a
maintenance plan for the area as meeting the requirements of CAA
section 175A. The maintenance plan must demonstrate continued
attainment of the relevant NAAQS in the area for at least 10 years
after our approval of the redesignation. Eight years after
redesignation, the state must submit a revised maintenance plan
demonstrating attainment for the 10 years following the initial 10-year
period. The maintenance plan must also contain a contingency plan to
ensure prompt correction of any violation of the NAAQS that occurs
after redesignation of the area. See CAA sections 175A(a), (b) and (d).
The Calcagni Memo provides additional guidance on the content of a
maintenance plan, stating that a maintenance plan should include the
following elements: (1) An attainment emissions inventory; (2) a
maintenance demonstration showing attainment for 10 years following
redesignation; (3) a commitment to maintain and operate an appropriate
air quality monitoring network; (4) verification of continued
attainment; and (5) a contingency plan to prevent or correct future
violations of the NAAQS. In this proposed action, EPA will review
requirements (3) and (4) together as part of our evaluation of LRAPA's
maintenance plan for the Oakridge area.
    In conjunction with Oregon's request to redesignate the Oakridge
area to attainment, Oregon submitted a SIP revision to provide for
maintenance of the 2006 24-hour PM2.5 NAAQS through 2035.
EPA proposes to approve LRAPA's PM2.5 maintenance plan for
the Oakridge area. The following paragraphs describe how each of the
maintenance plan elements are addressed in the maintenance plan.
1. Attainment Inventory
    As discussed in the CAA General Preamble (See 57 FR 13498, April
16, 1992) and the Calcagni Memo, PM2.5 maintenance plans
should include an attainment emission inventory to identify the level
of emissions in the area, which are sufficient to maintain the NAAQS.
The maintenance plan attainment inventory should be consistent with
EPA's emissions inventory requirements and most recent guidance on
emission inventories for nonattainment areas available at the time and
should represent emissions during the time period associated with the
monitoring data showing attainment.\18\ The inventory must also be
comprehensive, including emissions from stationary point sources, area
sources, mobile sources, and must be based on actual emissions during
the appropriate season, if applicable.
---------------------------------------------------------------------------

    \18\ See Calcagni Memo at 8.
---------------------------------------------------------------------------

    The EPA-approved 2017 Oakridge Update included projected 2015
PM2.5 attainment year emission inventories for the Oakridge
NAA. Oregon's January 13, 2022, Oakridge PM2.5 maintenance
plan submittal provided a revised and updated 2015 attainment year
inventory of actual emissions. The year 2015 is one of the years during
the time period where the Oakridge area first monitored attainment of
the 24-hour PM2.5 NAAQS (See section III.A of this
document).\19\ The 2015 maintenance plan attainment year emission
inventory is based on emission reduction strategies that were
implemented as of 2015.
---------------------------------------------------------------------------

    \19\ 83 FR 5537, February 8, 2018.
---------------------------------------------------------------------------

    The 2015 maintenance plan attainment year inventory includes
emissions of PM2.5, nitrogen oxides (NOX), sulfur
dioxide (SO2), ammonia (NH3) and volatile organic
compounds (VOCs). The 2015 attainment levels of point, area, on-road
mobile and nonroad mobile source emissions are summarized in Tables 3
and 4, along with future year projected emissions for a ``horizon
year'' (a future year at least 10 years from the approval date of the
maintenance plan) of 2035, and two interim years of 2025 and 2030.
    Oregon developed the attainment inventory based on the methods and
assumptions presented in detail in Appendix II of the Oakridge
PM2.5 maintenance plan (``Emision Inventory for 2015 Base
Year''). The attainment year inventory is based on typical season and
worst-case day (episodic) emissions. The typical season day emissions
represent an average daily emission value occurring from November 1
through the end of February. This four-month time period is considered
to be the particulate matter season and is when the PM2.5
standard has historically been exceeded. The worst-case day emissions
represent a day during the PM season when emissions generating activity
is at its highest due to meteorological factors like temperature.
However, residential woodburning and other area source emissions on
worst-case days are lower than on typical season days in the inventory
due to woodburning curtailments and outdoor burning bans. This approach
is consistent with the PM2.5 SIP Requirements Rule in which
EPA stated that an episodic period, developed in order to reflect
periods of higher emissions during periods of high ambient
PM2.5 can help, in some situations, to ensure the area's
inventory reflects the emissions conditions that led to the
nonattainment designation for the area (81 FR 58010, 58030, August 24,
2016).
    RWC emissions from certified and non-certified woodstoves,
fireplaces and pellet stoves continue to be the major source of
PM2.5 emissions on both typical season days and worst-case
winter days contributing to exceedances of the NAAQS.

                         Table 3--Oakridge PM2.5 Maintenance Plan Emissions Inventories
                                               [In pounds per day]
----------------------------------------------------------------------------------------------------------------
                                                                                Difference
                Source category                      2015         2025         2030         2035      from 2015
                                                  attainment    interim      interim    maintenance    and 2035
----------------------------------------------------------------------------------------------------------------
                                              PM Typical Season Day
----------------------------------------------------------------------------------------------------------------
Point..........................................          0.0          0.5          0.5          0.5          0.5
Area...........................................        444.8        364.1        364.0        363.5        -81.3
Onroad.........................................         34.4         23.0         22.1         22.1        -12.3
Nonroad........................................          2.7          2.7          2.7          2.7          0.0
                                                ----------------------------------------------------------------
    Total......................................        481.9        389.8        389.3        388.8        -93.1
----------------------------------------------------------------------------------------------------------------
                                                PM Worst-Case Day
----------------------------------------------------------------------------------------------------------------
Point..........................................          0.0          0.8          0.8          0.8          0.8
Area...........................................        334.5        250.9        233.8        216.5         -118
Onroad.........................................         41.4         26.6         26.6         24.7        -16.7
Nonroad........................................          2.7          2.7          2.7          2.7            0
                                                ----------------------------------------------------------------
    Total......................................        378.6        281.0        263.9        244.7       -133.9
----------------------------------------------------------------------------------------------------------------

    Secondary particulate is a very minor contributor to the Oakridge
PM2.5 air pollution concentrations on both typical season
days and worst-case winder days as summarized in Appendix II of the
Oakridge PM2.5 maintenance plan. Historical speciated
PM2.5 filter analyses indicate that concentrations of all
the precursors groups (NOX, SO2, NH3
and VOCs) were determined to be below insignificant thresholds (less
than 1.3 [micro]g/m\3\). The precursor emission shown in Table 4 are
projected to decrease between 2015 and 2035, indicating that precursor
emissions will continue to be below insignificant threshold
contributions to PM2.5 in the future.

                    Table 4--Oakridge PM2.5 Maintenance Plan Precursor Emissions Inventories
                                               [In pounds per day]
----------------------------------------------------------------------------------------------------------------
                                                                                Difference
         Source category               2015        2025 interim    2030 interim        2035       from 2015  and
                                    attainment                                      maintenance        2035
----------------------------------------------------------------------------------------------------------------
                                              NO Typical Season Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             5.1             5.1             5.1             5.1
Area............................            55.5            48.5            48.5            48.5            -7.0
Onroad..........................           613.6           171.2           103.2            87.8          -525.8
Nonroad.........................             0.1             0.1             0.1             0.1             0.0
                                 -------------------------------------------------------------------------------
    Total.......................           669.2           224.9           156.9           141.5          -527.7
----------------------------------------------------------------------------------------------------------------
                                                NO Worst-Case Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             8.7             8.7             8.7             8.7
Area............................            42.1            33.9            34.9            32.9            -9.2
Onroad..........................           711.3           193.1           127.9           108.8          -602.5
Nonroad.........................             0.1             0.1             0.1             0.1             0.0
                                 -------------------------------------------------------------------------------
    Total.......................           753.5           235.8           171.6           150.5          -603.0
----------------------------------------------------------------------------------------------------------------
                                              SO Typical Season Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             0.0             0.0             0.0             0.0
Area............................            11.2            10.3            10.3            10.3            -0.9
Onroad..........................             2.4             1.1             1.0             1.0            -1.4
Nonroad.........................             0.1             0.1             0.1             0.1             0.0
                                 -------------------------------------------------------------------------------
    Total.......................            13.7            11.5            11.4            11.4            -2.3
----------------------------------------------------------------------------------------------------------------
                                                SO Worst-Case Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             0.0             0.0             0.0             0.0
Area............................             7.0             5.9             5.6             5.2            -1.8
Onroad..........................             2.9             1.4             1.2             1.2            -1.7
Nonroad.........................             0.1             0.1             0.1             0.1             0.0
                                 -------------------------------------------------------------------------------

    Total.......................            10.0             7.4             6.9             6.5            -3.5
----------------------------------------------------------------------------------------------------------------
                                             VOC Typical Season Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             0.4             0.4             0.4             0.4
Area............................           507.0           349.3           346.0           341.7          -165.3
Onroad..........................           522.7           173.7            15.7            13.2          -509.5
Nonroad.........................             5.2             5.1             5.1             5.1            -0.1
                                 -------------------------------------------------------------------------------
    Total.......................         1,034.9           528.5           367.2           360.4          -674.5
----------------------------------------------------------------------------------------------------------------
                                               VOC Worst-Case Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             0.8             0.8             0.8             0.8
Area............................           321.2           179.3           165.1           150.5          -170.7
Onroad..........................           543.2           183.2            18.8            15.9          -527.3
Nonroad.........................             5.2             5.1             5.1             5.1            -0.1
                                 -------------------------------------------------------------------------------
    Total.......................           869.6           368.4           189.8           172.3          -697.3
----------------------------------------------------------------------------------------------------------------
                                              NH Typical Season Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             0.0             0.0             0.0             0.0
Area............................            30.0            25.4            25.4            25.4            -4.6
Onroad..........................             9.7             7.4             4.4             4.3            -5.4
Nonroad.........................             0.1             0.1             0.1             0.1             0.0
                                 -------------------------------------------------------------------------------
    Total.......................            39.8            32.9            29.9            29.8           -10.0
----------------------------------------------------------------------------------------------------------------
                                                NH Worst-Case Day
----------------------------------------------------------------------------------------------------------------
Point...........................             0.0             0.0             0.0             0.0             0.0
Area............................            18.2            13.5            12.6            11.8            -6.4
Onroad..........................            12.0             9.1             5.4             5.3            -6.7
Nonroad.........................             0.1             0.1             0.1             0.1             0.0
                                 -------------------------------------------------------------------------------
    Total.......................            30.3            22.7            18.1            17.2           -13.1
----------------------------------------------------------------------------------------------------------------

    In addition to the precursor assessment, LRAPA assessed the
condensable and filterable fractions of the PM2.5 emission
inventory. Since condensable and filterable emissions currently are not
required to be reported for the mobile source and the residential wood
combustion portion of the inventory and EPA's best tools to date do not
have a declarative answer for the condensable emissions portion for
these sources, there was no information to report. In addition,
condensable and filterable information for the other source categories
were similarly either unavailable or not applicable. Based on available
data sources, therefore, the condensible portion of PM2.5
was reported as zero in the 2015 emissions inventory and the projected
inventories do not include separately reported filterable and
condensable components of direct PM2.5 emissions.
    EPA has reviewed the results, procedures, and methodologies for the
Oakridge area 2015 attainment emissions inventories and proposes to
find that they are based on the most current and accurate information
available to LRAPA at the time they were developed. Based on our review
of the emissions inventories Oregon provided in its January 13, 2022
submittal, we propose to find that LRAPA prepared an adequate
attainment inventory for the Oakridge area.\20\
---------------------------------------------------------------------------

    \20\ See ``Emissions Inventory Guidance for Implementation of
Ozone and Particulate Matter National Ambient Air Quality Standards
(NAAQS) and Regional Haze Regulations,'' May 2017, available at
https://www.epa.gov/sites/default/files/2017-07/documents/ei_guidance_may_2017_final_rev.pdf.
---------------------------------------------------------------------------

2. Maintenance Demonstration
    CAA section 175A requires a state seeking redesignation to
attainment to submit a SIP revision to provide for maintenance of the
NAAQS in the area ``for at least 10 years after the redesignation.'' A
state can make this demonstration by either showing that future
emissions of a pollutant or its precursors will not exceed the level of
the attainment inventory, or by modeling to show that the future mix of
sources and emissions rates will not cause a violation of the
NAAQS.\21\
---------------------------------------------------------------------------

    \21\ See Calcagni Memo, pages 9-10.
---------------------------------------------------------------------------

    In its maintenance demonstration for the Oakridge area, LRAPA
elected to demonstrate maintenance of the 2006 PM2.5 NAAQS
for at least 10 years following redesignation using the attainment
inventory method. LRAPA developed projected inventories, provided in
Tables 3 and 4 of this document, to show that the Oakridge area will
remain in attainment through the year 2035. These projected
inventories, covering interim years 2025 and 2030 and a horizon year of
2035, show that future emissions of direct PM2.5 throughout
the nonattainment area will remain at or below the 2015 attainment-
level emissions for the 2006 24-hour PM2.5 NAAQS.
    The projected emissions inventories in the Oakridge
PM2.5 maintenance plan

address four major source categories: Point, area, onroad mobile and
nonroad mobile. Oregon estimated future year emission inventories using
the latest socioeconomic growth indictors and applying emissions
reduction benefits from adopted control strategies when appropriate. A
detailed description of the 2015 base year inventory and the 2025, 2030
and 2035 projected inventories can be found in Appendix III of LRAPA's
January 13, 2022, PM2.5 maintenance plan submittal, which is
in the docket for this action.
    As discussed in the Oakridge PM2.5 maintenance plan,
direct PM2.5 emissions estimates for stationary point
sources reflect actual emissions for both industrial point sources in
Oakridge. The Oakridge Sand & Gravel ready-mix concrete plant and rock
crusher did not operate in Oakridge in 2015, resulting in actual 2015
emissions that were zero. In addition, the ready-mix concrete plant air
discharge permit was terminated on January 24, 2014, resulting in zero
emissions in the 2015 and projected year emission inventories. Future
year emissions were therefore based on the January 2011
PM2.5 emissions at this source.
    Areawide sources occur over a wide geographic area with the most
significant emissions resulting from RWC sources such as fireplaces,
woodstoves and pellet stoves. These residential wood heating devices
are commonly used to heat homes in Oakridge since natural gas is not
available in this area. The permanent and enforceable RWC control
strategies are discussed in Section III.C. of this document. The only
other area source category with potentially significant emissions is
outdoor burning, which is banned in Lane County from November-February.
Emissions for these categories are derived using various surveys,
PM2.5 emission factors and other methodologies.
    Emissions from on-road mobile sources (exhaust, brake wear and tire
wear), which include passenger vehicles, buses, and trucks, were
estimated using MOVES2014a. Traffic growth in Vehicle-Miles Traveled
(VMT) was based on transportation modeling by the Lane Council of
Governments (LCOG) and the Oregon Department of Transportation (ODOT).
LRAPA confirmed re-entrained road dust calculations for both paved and
unpaved roads using AP-42 protocols. Federal control measures included
in the MOVES2014a modeling are all Federal measures that affect the
fleets and fuels used in future years once implemented by EPA.
    The nonroad emissions from railroads were calculated using the EPA
NONROAD2008a emission protocol. The National Emissions Inventories
(NEIs) for Lane County indicate a significant decrease in locomotive
emissions from 2008 to 2014 (40.09 tons/year and 18.26 tons/year,
respectively). The 2015 PM2.5 railroad emissions have been
adjusted to reflect the locomotive emission reductions as seen in the
2014 NEI data. Future year emissions are based on the adjusted 2014 and
2017 NEI data. All other Oakridge nonroad mobile sources are
categorized by LRAPA as insignificant during the PM2.5
winter season.
    EPA has reviewed the documentation provided by Oregon for
developing the projected 2025, 2030 and 2035 emissions inventories for
the Oakridge PM2.5 NAA. Based on our review, EPA finds that
the projected inventories were developed using appropriate procedures,
comprehensively address all source categories in the Oakridge area, and
sufficiently account for PM2.5 projected actual emissions.
These inventories indicate a decrease in PM2.5 and precursor
emissions throughout the maintenance period, therefore EPA proposes to
determine that the projected emissions inventories in the maintenance
plan sufficiently demonstrate that the Oakridge PM2.5 area
will continue to attain the 2006 24-hour PM2.5 standard
throughout the maintenance period.
3. Monitoring Network and Verification of Continued Attainment
    Once a nonattainment area has been redesignated to attainment, the
state must continue to operate an appropriate air quality monitoring
network, in accordance with 40 CFR part 58, to verify the attainment
status of the area. The maintenance plan should contain provisions for
continued operation of air quality monitors that will provide such
verification.
    In the Oakridge PM2.5 maintenance plan, LRAPA noted that
it currently operates a regulatory monitor (the Willamette Center since
1989) in the Oakridge NAA and committed to continue operating a
regulatory monitoring network through the year 2035 in order to verify
continued attainment of the PM2.5 NAAQS and track the
progress of the maintenance plan. LRAPA also stated it will continue
operation of the PM2.5 monitoring network as outlined in the
Oregon Annual Ambient Criteria Pollutant Air Monitoring Network Plan
(ANP) and any modification to the monitoring network will be done in
consultation with ODEQ and EPA Region 10. ODEQ and LRAPA will work with
EPA each year through the air monitoring network review process (per 40
CFR part 58) to determine the adequacy of the monitoring network.\22\
---------------------------------------------------------------------------

    \22\ See EPA's February 22, 2022 approval of Oregon's 2021
Annual Ambient Criteria Pollutant Air Monitoring Network Plan, in
the docket for this action.
---------------------------------------------------------------------------

    Oregon remains obligated to continue to quality-assure monitoring
data and enter all data into AQS in accordance with Federal guidelines.
LRAPA will review the air monitoring results and design values each
year to verify continued attainment. LRAPA will determine annually if
exceptional events influenced the continued attainment of the 2006 24-
hour PM2.5 NAAQS and need to be documented. If needed, ODEQ
and LRAPA will coordinate and provide exceptional events documentation
to EPA Region 10 for review.
    EPA proposes to determine that the Oakridge PM2.5
maintenance plan contains adequate provisions for continued operation
of an air quality monitoring network and a commitment to annually
verify continued attainment of the 2006 24-hour PM2.5 NAAQS
for the Oakridge area.
4. Contingency Plan
    CAA section 175A(d) requires that a maintenance plan also include
contingency provisions, as necessary, to promptly correct any violation
of the NAAQS that occurs after redesignation of the area to attainment.
For the purposes of CAA section 175A, a state is not required to have
fully adopted contingency measures that will take effect without
further action by the state in order for the maintenance plan to be
approved. However, the contingency plan is an enforceable part of the
SIP and should ensure that contingency measures are adopted
expeditiously once they are triggered. The contingency plan should
discuss the measures to be adopted and a schedule and procedure for
adoption and implementation. The contingency plan must require that the
state will implement all measures contained in the part D nonattainment
plan for the area prior to redesignation. The state should also
identify the specific indicators, or triggers, which will be used to
determine when the contingency plan will be implemented.\23\
---------------------------------------------------------------------------

    \23\ See Calcagni Memo at 12.
---------------------------------------------------------------------------

    The Oakridge PM2.5 maintenance plan outlines the
procedures for the adoption and implementation of contingency measures
to further reduce emissions should a violation of the 2006 24-hour
PM2.5 NAAQS occur. If the PM2.5 design

value indicates a violation of the standard, after consideration of any
exceptional events, the following contingency strategies, or
equivalent, will be implemented by LRAPA and the City of Oakridge:
     Stricter green-yellow-red advisory program,\24\ with more
red advisory days each winter, by reducing the red advisory thresholds
by 3 [micro]g/m\3\ PM2.5. This is projected to increase the
average number of potential red advisory days by three to five
additional days per year.
---------------------------------------------------------------------------

    \24\ LRAPA implements an advisory system that designates days as
green, yellow, or red when 24-hour PM levels reach certain
designated thresholds. During a red advisory day, LRAPA prohibits
the use of any solid fuel space heating device that emits visible
emissions into the air outside of the building housing the device
unless a specific exemption has been granted.
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     Prohibition of fireplace use on yellow advisory days (in
addition to the existing prohibition on red advisory days).
    While these measures do not need to be fully adopted by LRAPA prior
to the occurrence of a NAAQS violation, LRAPA commits to adopting and
implementing the necessary contingency measures as expeditiously as
possible, but not later than one year after a violation, based on
confirmed quality-assured data. Any contingency measures adopted and
implemented will become part of the control measures in the next
revised maintenance plan submitted to EPA for approval.
    LRAPA will evaluate all appropriate data including air quality
data, meteorological data, evaluation of wood smoke programs and
information on unusual weather events (e.g., wildfires or winter power
outages) and other data to determine the cause of the violation. LRAPA
will perform this evaluation within three months of the determination
of a violation. Where appropriate, LRAPA will follow EPA's exceptional
events rules and guidance if it is determined that an exceptional event
contributed to the violation.\25\
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    \25\ Treatment of Data Influenced by Exceptional Events, October
3, 2016, 81 FR 68216.
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    Based on our analysis of Oregon's submittal, we propose to find
that the contingency measure provisions provided in the Oakridge
PM2.5 maintenance plan are sufficient and meet the
requirements of CAA section 175A(d).

E. Transportation Conformity and Motor Vehicle Emissions Budgets

    Transportation conformity is required by CAA section 176(c). EPA's
conformity rule at 40 CFR part 93, subpart A requires that
transportation plans, programs, and projects conform to SIPs and
establishes the criteria and procedures for determining whether they
conform. 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. Thus, EPA's conformity rule
requires a demonstration that emissions from a Metropolitan Planning
Organization's Regional Transportation Plan and Transportation
Improvement Program, involving Federal Highway Administration or
Federal Transit Administration funding or approval, are consistent with
the MVEB(s) contained in a control strategy SIP revision or maintenance
plan (40 CFR 93.101, 93.118, and 93.124). A MVEB is the level of mobile
source emissions of a pollutant relied upon in the attainment or
maintenance demonstration to attain or maintain compliance with the
NAAQS in the nonattainment or maintenance area.
    A PM2.5 maintenance plan should identify MVEBs for
direct PM2.5, NOX and all other PM2.5
precursors from on-road mobile source emissions that are determined to
significantly contribute to PM2.5 levels in the area.\26\
All direct PM2.5 SIP budgets should include direct
PM2.5 motor vehicle emissions from tailpipe, brake wear and
tire wear. A State must also consider whether re-entrained paved and
unpaved road dust are significant contributors and should be included
in the direct PM2.5 budget.\27\
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    \26\ See 40 CFR 93.102(b)(2)(iv)-(v) and (b)(3).
    \27\ See 40 CFR 93.102(b), 93.122(f).
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    It should be noted that Oakridge is considered an isolated rural
nonattainment area within the meaning of 40 CFR 93.109(g), so
transportation conformity determinations are only required when a non-
exempt Federal Highway Administration or Federal Transit Administration
funded project is funded or approved.\28\
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    \28\ See 40 CFR 93.109(g).
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    The Oakridge PM2.5 maintenance plan includes direct
PM2.5 MVEBs for the attainment year (2015), two interim
years (2025 and 2030) and the maintenance horizon year (2035). See
Table 5, below. On February 8, 2018, EPA approved a 2015 attainment
year PM2.5 MVEB of 22.2 lb/day (83 FR 5537). The projected
MVEBs (2025, 2030 and 2035) reflect the total on-road PM2.5
worst-case day emissions (a sum of primary exhaust, brake wear and tire
wear), plus a portion of the available safety margin to accommodate
technical uncertainties due to model updates and inputs into the EPA
MOVES model and travel forecasting models as well as potential changes
to regional transportation plans. A safety margin is the amount by
which the total projected PM2.5 emissions from all sources
are less than the total emissions that would satisfy the NAAQS for the
2015 attainment year. With the safety margin applied to the future year
MVEB, the budgets still demonstrate maintenance of the 2006 24-hour
PM2.5 NAAQS.
    Oregon used the Motor Vehicle Emissions Simulator model,
MOVES2014a, during the development of the maintenance plan and executed
it with locally developed inputs representative of wintertime calendar
year 2015 conditions and future projections in order to appropriately
calculate the budgets. MOVES2014a was the accepted model when this work
began. EPA recently released MOVES3, but since sufficient work had
taken place on this SIP with MOVES2014a, we are accepting that mobile
model in this submittal (86 FR 1106, 1108, January 7, 2021). Traffic
growth in VMT for the Oakridge NAA is based on transportation modeling
by Lane County, LCOG and ODOT. The mobile source emissions, in total,
were modeled to steadily decrease between 2015 and 2035 as a result of
cleaner vehicles and cleaner fuels. The MVEBs are based on the control
measures in the maintenance plan and consistent with maintaining the
2006 24-hour PM2.5 NAAQS.
    As determined in the 2016 attainment plan approval (83 FR 5537,
February 8, 2018), secondary particulate are still minor contributors
to the Oakridge PM2.5 air pollution concentrations on worst-
case winter days as summarized in section III.D.1. Oregon excluded
paved road dust emissions and NOX emissions from the MVEB in
accordance with 40 CFR 93.102(b)(3). Vehicle emissions of
SO2 and NH3 were also found to contribute
minimally to PM2.5 in the area and therefore the maintenance
plan does not include MVEBs for these precursors in accordance with 40
CFR 93.102(b)(2)(v). See Appendix IV of LRAPA's Oakridge
PM2.5 maintenance plan, in the docket for this action, for
further analysis of the MVEB pollutants and precursors. Therefore,
based on its analysis, LRAPA set the Oakridge direct PM2.5
MVEBs for 2015, 2025, 2030 and 2035 as provided in Table 5 of this
proposed action. According to EPA's conformity rule, the emissions
budget acts as a ceiling on emissions in the year for which it is
defined or until a SIP revision modifies the budget.\29\
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    \29\ See 40 CFR 93.118.

                             Table 5--Direct PM2.5 MVEBs for the Oakridge PM2.5 NAA
----------------------------------------------------------------------------------------------------------------
                                                                                Year
             Motor vehicle emissions budgets             -------------------------------------------------------
                                                              2015          2025          2030          2035
----------------------------------------------------------------------------------------------------------------
Direct PM2.5 (lb/day)...................................         22.2           8.2           7.2           6.5
----------------------------------------------------------------------------------------------------------------

    For MVEBs to be approvable, they must meet, at a minimum, EPA's
adequacy criteria (40 CFR 93.118(e)(4)). EPA's process for determining
adequacy of a budget consists of three basic steps: (1) Notifying the
public of a SIP submittal; (2) providing the public the opportunity to
comment on the budget during a public comment period; and (3) making a
finding of adequacy or inadequacy. The process for determining the
adequacy of a submitted budget is codified at 40 CFR 93.118(f). EPA can
notify the public by either posting an announcement that EPA has
received SIP budgets on EPA's adequacy website (40 CFR 93.118(f)(1)),
or via a Federal Register notice of proposed rulemaking when EPA
reviews the adequacy of an implementation plan budget simultaneously
with its review and action on the SIP itself (40 CFR 93.118(f)(2)).
    Today, we are notifying the public that EPA will be reviewing the
adequacy of the 2015, 2025, 2030 and 2035 budgets in the Oakridge
PM2.5 maintenance plan. The public has a 30-day comment
period as described in the DATES section of this document. After this
comment period, EPA will indicate whether the budgets are adequate via
the final rulemaking on this proposed action or on the adequacy
website, according to 40 CFR 93.118(f)(2)(iii). The details of
EPA'evaluation of the budget for compliance with the budget adequacy
criteria of 40 CFR 93.118(e) are provided in a separate memorandum
included with the docket for this rulemaking.\30\ As noted earlier, the
public comment period for EPA's adequacy finding will be concurrent
with the public comment period for this proposed action on the Oakridge
PM2.5 Maintenance Plan.
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    \30\ See EPA memorandum titled, ``EPA Region 10 Adequacy Review
of Motor Vehicle Emissions Budgets in Oakridge PM2.5
Maintenance Plan'', dated April 6, 2022.
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    Based on the information presented in the Oakridge PM2.5
maintenance plan and our adequacy review to date, we propose to find
that Oregon has evaluated the appropriate pollutants and precursors and
appropriately established MVEBs for direct PM2.5 emissions.
EPA has reviewed the Oakridge PM2.5 maintenance plan's MVEBs
and found them to be consistent with the control measures in the SIP
and consistent with maintenance of the 2006 24-hour PM2.5
NAAQS within the Oakridge area through 2035. We propose to approve the
MVEBs in the Oakridge PM2.5 maintenance plan as meeting the
requirements of the CAA and EPA regulations.

F. State Rule Changes To Reflect the Redesignation

    Oregon adopted maintenance plans for both the Oakridge
PM2.5 and Oakridge PM10 area in the same state
rulemaking package and submitted them as a single SIP submittal to EPA.
This single submittal includes changes to LRAPA rules to reflect the
anticipated redesignation of both areas. Today's action addresses the
Oakridge PM2.5 area, and we are addressing the Oakridge
PM10 area in a separate action. However, in today's action,
for the sake of simplicity, we are proposing to approve all updates to
LRAPA rules to reflect the anticipated redesignation of both areas. We
believe this is appropriate because we intend to finalize our proposed
actions on both areas within the same time frame. In today's action,
EPA is proposing to approve revisions to LRAPA's Title 29 Designation
of Air Quality Areas, Section 29-0030(2) Designation of Nonattainment
Areas and Section 29-0040(3) Designation of Maintenance Areas. These
revisions will remove the Oakridge PM2.5 nonattainment areas
from the list of PM2.5 nonattainment areas and add them to
the list of PM2.5 maintenance areas within the federally-
approved Oregon SIP. EPA is also proposing to approve minor editorial
changes to LRAPA's Title 29 Designation of Air Quality Areas, Section
29-0010 Definitions and Section 29-0310 Designation of Reattainment
Areas, to consistently refer to the ``Oakridge PM2.5
Maintenance Area'' rather than the ``Oakridge PM2.5 Non-
attainment area.'' \31\
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    \31\ On January 13, 2022, Oregon also submitted LRAPA Title 29
Sections 0020, 0050-0090, 0300 and 0320. Oregon made no changes to
these sections, except for the State effective date. EPA has
reviewed these rules and approved them in a previous action (83 FR
50274, March 23, 2018).
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IV. Proposed Action

    EPA proposes to redesignate the Oakridge, Oregon PM2.5
NAA, and proposes approval of the associated maintenance plan for the
area. If this proposal is finalized, the designation status of the
Oakridge, Oregon PM2.5 NAA under 40 CFR part 81 will be
revised to attainment upon the effective date of that final action.
    EPA proposes to approve and incorporate by reference into the
Oregon SIP, the submitted revisions to LRAPA Title 29 Sections 29-0010,
29-0020, 29-0030(2), 29-0040(3), 29-0050, 29-0060, 29-0070, 29-0080,
29-0090, 29-0300, 29-0310 and 29-0320, state effective November 18,
2021.
    In addition, EPA proposes to approve and incorporate into the SIP
specific sections of the local rule submitted on January 20, 2017, and
the local rule submitted on January 13, 2022, as part of the
maintenance plan to the extent set forth in this document.
    EPA also proposes to take final agency action on Oregon's
exceptional event demonstration for the Oakridge PM10
monitor as discussed in this action.
    Finally, we propose that the Oakridge PM2.5 maintenance
plan's MVEBs meet applicable CAA requirements for maintenance plans and
transportation conformity requirements. With this action, we are
starting the adequacy process for these proposed MVEBs and opening a
public comment period.
    We note that the January 13, 2022 submittal also includes the
Oakridge PM10 redesignation and maintenance plan and
additional revisions to LRAPA's Title 29 rules, which EPA will address
in a separate action.

V. Incorporation by Reference

    In this document, EPA proposes to include, in a final rule,
regulatory text that includes incorporation by reference. In accordance
with the requirements of 1 CFR 51.5, EPA proposes to incorporate by
reference the provisions described in Section IV of this document,
specifically (1) The Lane County Code Chapter 9--Restriction on Use of
Solid Fuel Space Heating Devices, Sections 9.120-9.140, (2) the City of
Oakridge Ordinance No. 920--An Ordinance Amending Section 7 of
Ordinance 914 and Adopting New Standards for the Oakridge Air

Pollution Control Program; Section Two(3)--Solid Fuel Burning Devices--
Prohibitions and (3) revisions to LRAPA's Title 29 rules as described
in Section IV of this document.
    EPA has made, and will continue to make, these documents generally
available through https://www.regulations.gov and at the EPA Region 10
Office (please contact the person identified in the FOR FURTHER
INFORMATION CONTACT section of this preamble for more information).

VI. Statutory and Executive Orders Review

    Under the CAA, redesignation of an area to attainment and the
accompanying approval of a maintenance plan under section 107(d)(3)(E)
are actions that affect the status of a geographical area and do not
impose any additional regulatory requirements on sources beyond those
imposed by state law. A redesignation to attainment does not in and of
itself create any new requirements, but rather results in the
applicability of requirements contained in the CAA for areas that have
been redesignated to attainment. Moreover, the Administrator is
required to approve a SIP submittal that complies with the provisions
of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40
CFR 52.02(a). Thus, in reviewing SIP submittals, EPA's role is to
approve state choices, provided that they meet the criteria of the CAA.
Accordingly, this proposed action merely proposes to approve a State
plan and State law as meeting Federal requirements and does not impose
additional requirements beyond those already imposed by State law. For
that reason, this proposed action:
     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);
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     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.);
     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);
     Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     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
     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, this rule does not have tribal implications 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,
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,
Wilderness areas.

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

    Dated: April 25, 2022.
Michelle L. Pirzadeh,
Acting Regional Administrator, Region 10.
[FR Doc. 2022-09256 Filed 5-4-22; 8:45 am]
BILLING CODE 6560-50-P