[Federal Register Volume 82, Number 218 (Tuesday, November 14, 2017)]
[Proposed Rules]
[Pages 52683-52699]
[FR Doc No: 2017-24539]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R10-OAR-2017-0051; FRL-9970-71-Region 10]

Air Plan Approval; OR, Oakridge; PM2.5 Moderate Plan, Finding of
Attainment and Clean Data Determination

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to make
a finding of attainment by the attainment date and a clean data
determination (CDD) for the Oakridge-Westfir (Oakridge), Oregon fine
particulate matter nonattainment area (Oakridge NAA). The finding is
based upon quality-assured, quality-controlled, and certified ambient
air monitoring data showing the area has monitored attainment of the
2006 24-hour fine particulate matter (PM2.5) National
Ambient Air Quality Standards (NAAQS) based on 2014-2016 data available
in the EPA's Air Quality System (AQS) database. If finalized, this
determination will not constitute a redesignation to attainment.
    The EPA also proposes to approve revisions to Oregon's State
Implementation Plan (SIP) consisting of the updated Oakridge-Westfir
PM2.5

Attainment Plan (Oakridge Update) submitted by the Oregon Department of
Environmental Quality (ODEQ) on January 20, 2017. The purpose of the
Oakridge Update, developed by Lane Regional Air Protection Agency
(LRAPA) in coordination with the ODEQ, is to provide an attainment
demonstration of the 2006 24-hour PM2.5 NAAQS and correct
deficiencies in the 2012 Oakridge Attainment Plan.

DATES: Comments must be received on or before December 14, 2017.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2017-0051 at https://www.regulations.gov. Follow the online
instructions for submitting comments. Once submitted, comments cannot
be edited or removed from Regulations.gov. The EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
or other information 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. The 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,<PHONE_NUMBER>,
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document, wherever ``we'',
``us'' or ``our'' is used, it is intended to refer to the EPA.

Table of Contents:

I. Background for the EPA's Proposed Action
    A. Regulatory Background
    B. Oakridge NAA Background
II. Finding of Attainment by the Attainment Date and Clean Data
Determination
III. The EPA's Evaluation of the Oakridge Update
    A. Emissions Inventories
    B. Pollutants Addressed
    C. Reasonably Available Control Measures/Reasonably Available
Control Technology
    D. Modeling
    E. Attainment Demonstration
    F. Reasonable Further Progress (RFP) and Quantitative Milestones
(QM)
    G. Contingency Measures
    H. Motor Vehicle Emissions Budgets
IV. Proposed Action
V. Incorporation by Reference
VI. Statutory and Executive Order Reviews

I. Background for the EPA's Proposed Action

A. Regulatory Background

    On October 17, 2006, the EPA strengthened the 24-hour
PM2.5 NAAQS by lowering the level of the standard from 65
micrograms per cubic meter ([mu]g/m\3\) to 35 [mu]g/m\3\ in order to
provide increased protection of public health (40 CFR 50.13).\1\
Epidemiological studies have shown statistically significant
correlations between elevated PM2.5 (particulate matter 2.5
micrometers in diameter and smaller) levels and premature mortality.
Other important adverse health effects associated with elevated
PM2.5 exposure include aggravation of respiratory and
cardiovascular disease (as indicated by increased hospital admissions,
emergency room visits, absences from school or work, and restricted
activity days), changes in lung function and increased respiratory
symptoms. Individuals particularly sensitive to PM2.5
exposure include older adults, people with heart and lung disease, and
children (78 FR 3088, January 15, 2013). PM2.5 can be
emitted directly into the atmosphere as a solid or liquid particle
(``primary PM2.5'' or ``direct PM2.5'') or can be
formed in the atmosphere as a result of various chemical reactions
among precursor pollutants such as nitrogen oxides, sulfur oxides,
volatile organic compounds, and ammonia (``secondary
PM2.5'').\2\
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    \1\ See 71 FR 61224 (October 17, 2006). The EPA set the first
NAAQS for PM2.5 on July 18, 1997 (62 FR 36852), including
annual standards of 15.0 [mu]g/m\3\ based on a 3-year average of
annual mean PM2.5 concentrations and 24-hour (daily)
standards of 65 [mu]g/m\3\ based on a 3-year average of 98th
percentile 24-hour concentrations (40 CFR 50.7). Unless otherwise
noted, all references to the PM2.5 standard in this
notice are to the 2006 24-hour standard of 35 [mu]g/m\3\ codified at
40 CFR 50.13.
    \2\ See EPA, Regulatory Impact Analysis for the Final Revisions
to the National Ambient Air Quality Standards for Particulate Matter
(EPA-452/R-12-005, December 2012), p. 2-1.
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    Following promulgation of a new or revised NAAQS, the EPA is
required by section 107(d)(1) of the CAA to designate areas throughout
the United States as attainment, nonattainment, or unclassifiable for
the NAAQS. Nonattainment areas include both areas that are violating
the NAAQS, and nearby areas with emissions sources or activities that
contribute to violations in those areas. States with areas designated
nonattainment are required to prepare and submit a plan for attaining
the NAAQS in the area as expeditiously as practicable.
    The requirements for attainment plans for the 2006 24-hour
PM2.5 NAAQS include the general nonattainment area planning
requirements in CAA section 172 of title I, part D, subpart 1 (subpart
1) and the additional planning requirements specific to particulate
matter in CAA sections 188 and 189 of title I, part D, subpart 4
(subpart 4). The EPA has a longstanding general guidance document that
interprets the 1990 amendments to the CAA, commonly referred to as the
``General Preamble'' (57 FR 13498, April 16, 1992). The General
Preamble addresses the relationship between subpart 1 and subpart 4
requirements and provides recommendations to states for meeting
statutory requirements for particulate matter nonattainment planning.
Specifically, the General Preamble explains that requirements
applicable to Moderate area nonattainment SIPs are set forth in subpart
4, but such SIPs must also meet the general nonattainment planning
provisions in subpart 1, to the extent these provisions ``are not
otherwise subsumed by, or integrally related to,'' the more specific
subpart 4 requirements (57 FR 13538). On August 16, 1994, the EPA
promulgated an addendum to the General Preamble providing additional
guidance for particulate matter nonattainment areas (59 FR 41988).
Additionally, on August 24, 2016, the EPA issued a final rule, Fine
Particulate Matter National Ambient Air Quality Standards: State
Implementation Plan Requirements (PM2.5 SIP Requirements
Rule) (81 FR 58009), to clarify our interpretations of the statutory
requirements that apply to PM2.5 nonattainment areas.
    The requirements of subpart 1 for attainment plans include, among
other things: (i) The section 172(c)(1) requirements to provide for the
implementation of reasonably available control measures (RACM),
including reasonably available control technology (RACT), and
attainment of the NAAQS; (ii) the section 172(c)(2) requirement to
demonstrate reasonable further progress (RFP); (iii) the section
172(c)(3) requirement for emissions inventories; and (iv) the section
172(c)(9) requirement for contingency measures.
    The subpart 4 requirements for Moderate areas are generally
comparable with the subpart 1 requirements and include: (i) Section
189(a)(1)(B) requirements to demonstrate attainment by the outermost
statutory Moderate area attainment date (i.e., the end of the sixth
calendar year following designation) or

that attainment by such date is impracticable; (ii) section
189(a)(1)(C) requirements to ensure RACM will be implemented within
four years of designation; (iii) section 189(c) requirements for RFP
and quantitative milestones (QMs); and (iv) section 189(e) control
requirements for precursor emissions from major stationary sources. In
this action, the EPA is evaluating the Oakridge Update for compliance
with the statutory and regulatory requirements applicable to Moderate
PM2.5 nonattainment areas.

B. Oakridge NAA Background

    In 1994, the EPA designated Oakridge a nonattainment area for
PM10--particulate matter ten micrometers and smaller. In
1996, LRAPA in coordination with the ODEQ, prepared and submitted a
PM10 attainment plan for Oakridge. The EPA approved it on
March 15, 1999 (64 FR 12751). On July 26, 2001, EPA published a finding
of attainment for the Oakridge PM10 NAA (66 FR 38947).
However, the designation status in 40 CFR part 81 remains Moderate
nonattainment for the area until such time as LRAPA meets the CAA
requirements for redesignaton to attainment. A redesignation request
and maintenance plan for PM10 has not been submitted. The
area has continued to attain the PM10 NAAQS.
    In 1997, the EPA revised the particulate standard to include
PM2.5 at a daily standard of 65 [mu]g/m\3\. Due to the same
set of control measures that it used to address exceedances of the
PM10 standard, Oakridge successfully remained below the
PM2.5 standard promulgated in 1997. When the EPA tightened
the PM2.5 standard from 65[mu]g/m\3\ to 35[mu]g/m\3\ in
2006, Oakridge was found to be violating the new standard. The air
quality monitoring data at the Willamette Activity Center (WAC) was
evaluated for 2006-2008, resulting in a design value of 40 [mu]g/m\3\.
The EPA designated Oakridge, Oregon as nonattainment for the 2006 24-
hour PM2.5 NAAQS on November 13, 2009 (74 FR 58689),
prompting the development of the PM2.5 Attainment Plan for
the Oakridge, Oregon NAA (Oakridge Attainment Plan). The EPA
subsequently classified the area as Moderate nonattainment for the 2006
24-hour PM2.5 standard (79 FR 31565, June 2, 2014).\3\
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    \3\ On January 4, 2013, the D.C. Circuit Court issued a decision
in NRDC v. EPA, 706 F.3d 428, holding that the EPA erred in
implementing the 1997 PM2.5 NAAQS pursuant to the general
implementation provisions of subpart 1 of Part D of Title I of the
CAA (subpart 1), rather than the particulate-matter-specific
provisions of subpart 4 of Part D of Title I (subpart 4). Prior to
the January 4, 2013 Court decision, states had worked towards
meeting the air quality goals of the 2006 PM2.5 NAAQS in
accordance with the EPA regulations and guidance derived from
subpart 1 of Part D of Title I of the CAA. The EPA considered this
history in issuing the PM2.5 Subpart 4 Nonattainment
Classification and Deadline Rule (79 FR 31566, June 2, 2014) that
identified the initial classification under subpart 4 for areas
currently designated nonattainment for the 1997 and/or 2006
PM2.5 standards as moderate.
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    On December 12, 2012, LRAPA, in coordination with the ODEQ,
submitted the Oakridge Attainment Plan. On October 21, 2016, the EPA
finalized partial approval and partial disapproval of this plan (81 FR
72714). In that action, the EPA approved the description of the
Oakridge NAA and listing as nonattainment, and the 2008 base year
emission inventory as meeting the section 172(c)(3) requirement for
emissions inventories. The EPA disapproved all other elements of the
submittal. The disapproval action for the Oakridge Attainment Plan
started a sanctions clock for the imposition of offset sanctions and
highway sanctions 18 months and 24 months respectively after the
November 21, 2016 effective date, pursuant to section 179(a) of the CAA
and our regulations at 40 CFR 52.31. In addition to sanctions, the EPA
must promulgate a FIP no later than two years from the date of the
finding if the deficiency has not been corrected within that time
period.
    The Oakridge Attainment Plan included control measures that were
fully implemented and modeled attainment by the December 2014 deadline.
However, leading up to the deadline, the 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 was
finalized. The rule classified Oakridge as Moderate and established
December 31, 2015, as the attainment date deadline for the Oakridge NAA
(79 FR 31565, June 2, 2014). This decision was based on the fact that
subpart 4 of the CAA requires a Moderate area attainment date to be no
later than the end of the 6th calendar year after designation. The
applicable attainment date for Oakridge changed from December 2014 to
December 2015.
    In order to measure progress towards meeting the attainment date,
both LRAPA and the EPA followed monitoring data closely to ensure the
area was meeting targets consistent with the modeling demonstration
submitted in the 2012 Oakridge Attainment Plan. Prior to the December
31, 2015, attainment date deadline, LRAPA determined Oakridge would not
come into attainment based on 2013-2015 monitoring data. Under section
188(d), the EPA has discretion to grant an extension to the attainment
date for an area if the state requests the extension and meets the
statutory criteria for such an extension. On December 14, 2015, LRAPA
requested a 1-year extension of the 2015 attainment date for the
Oakridge NAA. On July 18, 2016, the EPA granted a 1-year extension of
the 2006 24-hour attainment date for the Oakridge NAA (81 FR 46612)
from December 31, 2015 to December 31, 2016 (extended attainment date),
on the basis that the State met the criteria for such an extension
under the CAA.
    Notwithstanding the extension of the attainment date to December
31, 2016, the applicable Moderate area attainment demonstration date
for the Oakridge NAA remains December 31, 2015. The PM2.5
SIP Requirements Rule provides that a state's modeled attainment
demonstration needs to establish that an area will attain the NAAQS by
the projected attainment date. Practically speaking, this is considered
satisfied by the modeling showing that the 98th percentile is below the
standard for the attainment year (81 FR 58010, at page 58054).
    The EPA authorizes this approach because of the potential
availability of extensions of the attainment date under relevant
provisions of the CAA. In other words, if ambient data show attainment-
level concentrations in the final statutory attainment year, but the
three-year average does not demonstrate attainment, a state may be
eligible for up to two 1-year extensions of the attainment date. See 40
CFR 51.1005. Extensions of the attainment date are available to
accommodate states that may be able to attain the NAAQS by the extended
attainment date, even if the measured design value for an area does not
meet the NAAQS by the end of the 6th calendar year after designation.
For this reason, the EPA's PM2.5 SIP Requirements Rule
indicates that it is acceptable for a state to model air quality levels
for the final statutory attainment year in which the area is required
to attain the standard (in this case 2015).
    Because the initial Oakridge Attainment Plan did not adequately
address the PM2.5 problems in the airshed or meet the
requirements of the CAA and the PM2.5 SIP Requirements Rule,
LRAPA developed the Oakridge Update that was subsequently adopted and
submitted by the ODEQ to the EPA on January 20, 2017. The Oakridge
Update was submitted to satisfy the requirement for an updated

comprehensive 2008 base year emission inventory and the 2015 attainment
projected inventory for direct PM2.5 emissions and all
PM2.5 precursors, an analysis and selection of reasonably
available control measures and reasonably available control
technologies (RACM and RACT), an attainment demonstration based on
permanent and enforceable requirements, contingency measures, and
quantitative milestones (QM) demonstrating reasonable further progress
(RFP) toward attainment. The attainment plan's strategy for controlling
direct PM2.5 emissions relies primarily on an episodic wood
stove curtailment program and a program to change out uncertified wood
stoves.

II. Finding of Attainment by the Attainment Date and Clean Data
Determination

    Under CAA section 188(b)(2) the EPA is required to determine within
six months of the applicable attainment date whether a nonattainment
area attained the standard by that date. As discussed above, on July
18, 2016, the EPA granted a 1-year extension of the attainment date
from December 31, 2015 to December 31, 2016 (81 FR 46612). Under the
EPA regulations at 40 CFR part 50, Appendix N, the 2006 primary and
secondary 24-hour PM2.5 NAAQS are met within a nonattainment
area when the 24-hour PM2.5 NAAQS design value at each
eligible monitoring site is less than or equal to 35 [mu]g/m\3\. Three
years of valid annual PM2.5 98th percentile mass
concentrations are required to produce a valid 24-hour PM2.5
NAAQS design value.
    The EPA's finding of attainment is based upon data that has been
collected and quality-assured in accordance with 40 CFR part 58 and
recorded in the EPA Air Quality System (AQS) database. Ambient air
quality monitoring data for the 3-year period must meet data
completeness requirements. The ambient air quality monitoring data
completeness requirements are met when quarterly data capture rates for
all four quarters in a calendar year are at least 75 percent.
    The EPA reviewed the PM2.5 ambient air monitoring data
from the Willamette Activity Center (WAC) (AQS site 41-039-2013)
consistent with the requirements contained in 40 CFR part 50, as
recorded in the EPA AQS database for the Oakridge NAA. For purposes of
determining attainment by the December 31, 2016 extended attainment
date, the EPA determined that the data recorded in the AQS database was
certified and complete.
    The design value (the metrics calculated in accordance with 40 CFR
part 50, appendix N, for determining compliance with the NAAQS) for the
2006 24-hour PM2.5 NAAQS for the years 2014-2016 at the WAC
was calculated to be 31 [mu]g/m\3\, which is less than the standard of
35 [mu]g/m\3\. See Table 1 below for the annual 98th percentiles and 3-
year design value for the 2014-2016 monitoring period. On the basis of
this review, we are proposing to determine, based on complete, quality-
assured, and certified data for 2014-2016, that the Oakridge NAA
attained the 2006 24-hour PM2.5 NAAQS by the extended
attainment date. This determination of attainment by the attainment
date does not constitute a redesignation to attainment. Rather,
redesignations require states to meet a number of additional statutory
criteria in CAA section 107(d)(3)(E), including EPA approval of a state
plan demonstrating maintenance of the air quality standard for 10 years
after redesignation. CAA section 107(d)(3)(E)(iv).

                             Table 1--2014-2016 Oakridge Area PM2.5 Monitoring Data
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                                                           98th percentile  ([mu]g/m\3\)           2014-2016 24-
                                                 ------------------------------------------------  hour  design
          Monitor name              AQS site ID                                                   value  ([mu]g/
                                                       2014            2015            2016            m\3\)
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Willamette Activity Center......     41-039-2013            41.1            28.9            21.7              31
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    Additionally, the EPA is proposing to determine that the area has
clean data for demonstrating attainment of the 2006 24-hr
PM2.5 NAAQS. A clean data determination (CDD) can be made
upon a determination by the EPA that a Moderate PM2.5 NAA is
attaining the PM2.5 NAAQS. Under a CDD, the requirements for
the area to submit an attainment demonstration, associated RACM, RFP
plan, contingency measures, and any other planning SIP requirements
related to attainment of the 2006 24-hour PM2.5 NAAQS are
suspended for so long as the area continues to meet the relevant NAAQS
(40 CFR 51.1015, August 24, 2016), and the FIP and sanctions clocks are
also tolled for the pendency of the CDD. If the EPA subsequently
determines that the area is in violation of the 2006 24-hour
PM2.5 NAAQS, the EPA would rescind the CDD, the state would
again be required to submit the suspended attainment plan elements to
the EPA, and the FIP and sanctions clocks would resume. See 40 CFR
51.1015(a)(2).
    Although a CDD suspends the requirement for submission of certain
attainment planning elements, it does not relieve the EPA of its
responsibility to take action on a state's SIP submission. Oregon
submitted the Oakridge Update to address the previously disapproved
elements of the SIP and EPA is proposing to approve the state's
revisions. In the event that EPA determines in its final action that
the Oakridge Update should not be approved, the Clean Data
Determination (if finalized as proposed) would suspend Oregon's
obligation to submit a revised SIP to address the attainment planning
requirements related to attainment of the 2006 24-hour PM2.5
NAAQS, and as noted above, would toll the FIP and sanctions clocks that
were started by the EPA's prior disapprovals as long as the area
continues to attain the standard.
    Neither the proposed finding of attainment by the attainment date
nor CDD is equivalent to the redesignation of the area to attainment.
This proposed action, if finalized, will not constitute a redesignation
to attainment under section 107(d)(3)(E) of the CAA, because the state
must have an approved maintenance plan for the area as required under
section 175A of the CAA, and a determination that the area has met the
other requirements for redesignation in order to be redesignated to
attainment. The designation status of the area will remain
nonattainment for the 2006 PM2.5 NAAQS until such time as
the EPA determines that the area meets the CAA requirements for
redesignation to attainment in CAA section 107(d)(3)(E).

III. The EPA's Evaluation of the Oakridge Update

    On January 20, 2017, the ODEQ in coordination with LRAPA submitted
the Oakridge Update to satisfy the Moderate

nonattainment area CAA requirements. In accordance with Sections 172(c)
and 189 of the CAA, the Oakridge Update includes emissions inventories,
an evaluation of precursors for control in the area, RACM/RACT
demonstrations for direct PM2.5 and PM2.5
precursors, an attainment demonstration, QM and RFP requirements, and
contingency measures. The SIP submittal also addresses motor vehicle
emissions budgets (MVEBs). Each of these elements is discussed below.
The primary control strategy in the Oakridge Update is reducing
emissions from residential wood combustion.
    The air pollution ordinances adopted by the City of Oakridge from
2012-2016 (ordinances 903, 913, 914 and 920) require emission
reductions contributing to the 2015 attainment demonstration and the
monitored attainment of the 2006 24-hr PM2.5 NAAQS by the
December 31, 2016, extended attainment date. Each ordinance, in
succession, provides further strengthening of the control measures and
maintains the integrity of the prior ordinance(s). The most recent city
ordinance (ordinance 920), passed by the City of Oakridge and adopted
by LRAPA on November 21, 2016, supersedes the previous air pollution
ordinances and requires the continued implementation of the control
strategies in a manner that is both permanent and enforceable.
    The EPA has evaluated the Oakridge Update to determine whether it
meets the applicable CAA requirements of subpart 1 and subpart 4, as
specified in the PM2.5 SIP Requirements Rule. Based on this
evaluation, the EPA is proposing to approve the following elements of
the Oakridge Update.

A. Emissions Inventories

1. Requirements for Emissions Inventories
    Section 172(c)(3) of the CAA requires a state with an area
designated as nonattainment to submit a ``comprehensive, accurate,
current inventory of actual emissions from all sources of the relevant
pollutant'' for the nonattainment area. By requiring an accounting of
actual emissions from all sources of the relevant pollutants in the
area, this section provides for the base year inventory to include all
emissions from sources in the nonattainment area that contribute to the
formation of a particular NAAQS pollutant. For the 2006 24-hour
PM2.5 NAAQS, this includes direct PM2.5
(condensable and filterable) as well as the precursors to the formation
of secondary PM2.5: Nitrogen oxides (NOX), sulfur
dioxide (SO2), volatile organic compounds (VOCs), and
ammonia (NH3) (40 CFR 51.1008; 81 FR 58028). Inclusion of
PM2.5 and all of the PM2.5 precursors in the
emissions inventory is necessary in order to inform other aspects of
the attainment plan development process, such as ascertaining which
pollutants a state must control in order to attain the NAAQS in the
area expeditiously.
    In addition to the base year inventory submitted to meet the
requirements of CAA section 172(c)(3), the state must also submit an
attainment projected inventory for the NAA for the attainment year and
each QM year, and any other year of significance for meeting applicable
CAA requirements. Projected emission inventories for future years must
account for, among other things, the ongoing effects of economic growth
and adopted emissions control requirements, and are expected to be the
best available representation of future emissions. The SIP submission
should include documentation explaining how the state calculated the
emissions data for the base year and projected inventories. The
specific PM2.5 emissions inventory requirements are set
forth in 40 CFR 51.1008. The EPA has provided additional guidance for
developing PM2.5 emissions inventories in Emissions
Inventory Guidance for Implementation of Ozone and Particulate Matter
National Ambient Air Quality Standards (NAAQS) and Regional Haze.\4\
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    \4\ The EPA's Emissions Inventory Guidance for Implementation of
Ozone and Particulate Matter National Ambient Air Quality Standards
(NAAQS) and Regional Haze is available at https://www.epa.gov/air-emissions-inventories/emissions-inventory-guidance-documents.
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2. Emissions Inventories in the Oakridge Update
    The Oakridge Update has two emissions inventories for the area: a
2008 base year inventory for the nonattainment area and the 2015
attainment projected inventory for the nonattainment area. In addition,
LRAPA developed a projected emissions inventory for 2016 for
informational purposes to demonstrate the further effectiveness of the
field compliance improvements and curtailment program for year 2015.
Each inventory presents PM2.5 emissions and emissions of all
PM2.5 precursors (NOX, VOCs, NH3, and
SO2) to meet the comprehensive emissions inventory
requirements of CAA section 172(c) and section 189(a)(1)(B) for the
2006 24-hour PM2.5 NAAQS. LRAPA provided inventories from
all sources in the Oakridge NAA, including stationary point sources,
stationary nonpoint (area sources), on-road mobile sources and non-road
mobile sources.
    The inventories are based on Typical Season Day and Worst Case Day
emissions. LRAPA chose to develop a seasonal inventory representing a
four-month period in 2008 (January, February, November, and December)
during the wood-heating season. The agency examined ambient
PM2.5 data from the Willamette Activity Center and
determined that values approaching the 2006 24-hour PM2.5
NAAQS of 35 [mu]g/m\3\ only occur in the four-months when low
temperatures spur higher home heating emissions and when stagnant air
masses inhibit dispersion of air pollution. Therefore, the Typical
Season Day inventory represents a seasonal inventory for the period of
the year relevant for attainment planning. The Typical Season Day
emissions are the daily rate of emissions for the four-month season.
However, stagnant meteorological conditions are highly episodic and
only occur for a portion of the season. Outside of these meteorological
conditions, PM2.5 levels are well below the 2006 24-hour
PM2.5 NAAQS. To best represent emissions during exceedances
of the standard rather than an average of polluted and clean periods,
LRAPA developed a ``Worst Case Day'' emission inventory for weather
conditions that represent exceedance days.
    Stationary Point Sources: The only operating industrial point
sources within the Oakridge NAA are two minor aggregate industry
sources (a rock crusher and concrete batch plant which shut down in
2014). These two minor sources together contribute less than 1% to base
year and 0% to future year emission inventories. For the base year
inventory, actual emissions were based on average actual production
rates and calculated emissions during the months of November-February
(2008-2011), worst-case day emissions were based on actual production
rates and calculated emissions during the highest production month
during November-February (2008-2011). On May 17, 2017, LRAPA submitted
a clarification to the future year (2015) emissions reported in the
Oakridge Update. The actual point source emissions based on actual
production rates calculated for 2015 (January, February, November, and
December) are 0% since the concrete batch plant is no longer in
operation and the rock crushing operation did not operate in 2015.
    Nonpoint/Area Sources: The most significant source category is
residential wood combustion (RWC). Emissions from certified and non-
certified wood

stoves, fireplaces, and pellet stoves account for about 86% of the base
year direct PM2.5 emissions and 84% of the projected 2015
emissions on worst case winter days. To estimate emissions from RWC,
LRAPA conducted a survey for the 2009-2010 heating season. The survey
provided LRAPA with information on how many homes use various types of
wood-heating devices, the amount of wood burned, and other information
on wood-heating practices. The survey report, data, and additional RWC
emission calculation details are included in Appendix D-2 of the 2012
Oakridge Attainment Plan. The only other nonpoint area source category
with potential emissions is backyard burning which is banned in
Oakridge during November-February. These emissions are estimated as 4.7
lb./day on worst-case days.
    On-road and Non-road Sources: Road dust and tailpipe emissions from
motor vehicles were initially calculated by the Lane Council of
Governments (LCOG) by applying emission factors from the EPA MOVES2010a
computer program. These were recently updated by the ODEQ in 2016 using
the EPA MOVES2014a program using inputs and VMT compiled by LCOG in
2012 and incorporating the effects of three new federal emission
control programs. Emissions from railroads were provided by Union
Pacific Railroad.
    It has been determined that condensable emissions currently are not
required to be reported for the mobile source and residential wood
combustion portion of the inventory since the EPA's best tools to date
do not have a declarative answer for the condensable emissions portion
for these sources. In addition, the point source, non-road and the
``all other stationary area source'' categories, which constitute 0.1%,
1% and 1% respectively of the worst-case day direct PM2.5
emissions (2008 base year EI) and 0%, 1% and 1% respectively of the
worst-case day emissions (2015 projected year EI), are too small to
justify the need to break out condensable emissions. Thus the 2008 and
2015 inventories for the Oakridge NAA do not include separately
reported filterable and condensable components of direct
PM2.5 emissions.
a. 2008 Base Year Emissions Inventory for the Nonattainment Area
    LRAPA selected the year 2008 as the base year of the emissions
inventory for the nonattainment area. The 2008 base year inventory is
one of the three years used to designate the area as nonattainment and
was inventoried for the National Emission Inventory. It is also the
middle year of the five-year period, 2006-2010, used for determining
the base design value. This inventory provides the basis for the
control measure analysis and the attainment demonstration in the
Oakridge Update.
    The 2008 base year emission inventory for the nonattainment area
was initially submitted as part of the 2012 Oakridge Attainment Plan
and approved in a final rulemaking action completed on October 21, 2016
(81 FR 72714). The Oakridge Update contains a revised 2008 base year
emission inventory for the nonattainment area because an updated
version of MOVES (2014a) was available for calculating on-road
emissions. LRAPA surveyed all source sectors within the nonattainment
area and developed accurate, actual emissions for sources as they
existed in 2008 using well established techniques. Table 2 presents a
summary of both seasonal inventories and the annual average daily
precursor emissions.

Table 2--2008 PM2.5 Base Year Typical Season Day and Worst-Case Day Emissions; and 2008 Precursor Annual Average
                                                 Daily Emissions
----------------------------------------------------------------------------------------------------------------
                                      Typical season  Worst case day      Annual average daily values lbs/day
                                        day lbs/per     lbs/per day  -------------------------------------------
        Source type category                day      ----------------
                                     ----------------                    SO2        NOX        VOC        NH3
                                           PM2.5           PM2.5
----------------------------------------------------------------------------------------------------------------
Stationary Point (actuals)..........             0.5             0.9       * na       * na       * na       * na
Nonpoint/Area.......................           479.5             480        2.9       12.8      216.8        5.3
On-road.............................            41.4            64.7       10.6      866.7      434.4       13.8
Non-road............................             6.0             6.0        1.3        101       18.2        .05
                                     ---------------------------------------------------------------------------
    Total...........................             527             552         15        980        670       19.2
----------------------------------------------------------------------------------------------------------------
* These emissions are accounted for in the 2008 NEI but are grouped into the nonpoint/area source category.

b. Attainment Projected Emissions Inventory for the Nonattainment Area
    In addition to developing a 2008 base year inventory, LRAPA
developed a projected year inventory for 2015. This inventory is
relevant to the December 31, 2015 attainment demonstration. LRAPA
developed the 2015 projected year inventory by estimating the impact on
emissions from anticipated demographic and economic trends and from
adopted federal, state and local control measures in effect through
December 31, 2014. A summary of the Oakridge NAA 2015 projected
seasonal inventory is provided in Table 3.

Table 3--2015 PM2.5 Estimated Typical Season Day and Worst-Case Day Emissions; and 2014 Annual Average Precursor
                                                    Emissions
----------------------------------------------------------------------------------------------------------------
                                      Typical season  Worst case day      Annual average daily values lbs/day
                                        day lbs/per     lbs/per day  -------------------------------------------
        Source type category                day      ----------------
                                     ----------------                    SO2        NOX        VOC        NH3
                                           PM2.5           PM2.5
----------------------------------------------------------------------------------------------------------------
Stationary Point (actuals)..........               0               0          0          0          0          0
Nonpoint/Area.......................           444.8           334.5        3.0       10.7      120.4        2.1
On-road.............................            24.7            38.5        3.0      598.3      339.8       11.5
Non-road............................             6.0             6.0        1.1       77.3       14.4        .05
                                     ---------------------------------------------------------------------------

    Total...........................             475             379          7        686        475         14
----------------------------------------------------------------------------------------------------------------

3. The EPA's Evaluation and Proposed Action: Emissions Inventories for
the Nonattainment Area
    The EPA has reviewed the results, procedures, and methodologies for
the Oakridge NAA emissions inventories. The EPA has determined that the
2008 base year inventory for the nonattainment area and the 2015
attainment projected inventory for the nonattainment area are based on
the most current and accurate information available to LRAPA at the
time the Oakridge Update and its inventories were being developed. The
selection of 2008 as a base year is consistent with emissions inventory
requirements in 40 CFR 51.1008(a)(1)(i) because it is one of three
years used to designate the area as nonattainment and it is also a year
already inventoried for the National Emission Inventory. Weather
conditions in 2008 were typical and temperature-dependent emissions
from home heating and from mobile sources are considered representative
for the 2006-2010 period. The selection of 2015 for the attainment
projected inventory for the nonattainment area is consistent with 40
CFR 51.1008(2)(2)(i) because 2015 is the attainment year in the
attainment demonstration.
    The EPA finds the worst case day (episodic) approach that LRAPA
used for the 2008 and 2015 inventories to be consistent with the
PM2.5 SIP Requirements Rule in which the 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 nonattainment area inventory reflects
the emissions conditions that led to the nonattainment designation for
the area (81 FR 58030). This seasonal Worst Case Day inventory is the
most relevant and accurate for nonattainment area planning.
    Additionally, the 2008 and 2015 inventories sufficiently account
for PM2.5 emissions as required in 40 CFR 51.1008(a)(1)(iv)
and (a)(2)(iv). The inventories comprehensively address all source
categories in the Oakridge NAA, actual emissions are provided, and
appropriate procedures were used to develop the inventories. We are
therefore proposing to approve the updated 2008 base year worst-case
day emissions inventory for the Oakridge NAA as meeting the
requirements of CAA section 172(c)(3) and 40 CFR 51.1008(a)(1), and we
are proposing to approve the 2015 projected year worst-case day
inventory for the Oakridge NAA as meeting the requirements of 40 CFR
51.1008(a)(2). We are also proposing to find that the 2008 base year
inventory in the Oakridge Update provides an adequate basis for the
control strategy analysis, the attainment demonstration, and
demonstrating RFP (discussed in sections II.C, E and F, respectively).

B. Pollutants Addressed

1. Requirements for the Control of Direct PM2.5 and
Precursors
    The composition of PM2.5 is complex and highly variable
due in part to the large contribution of secondary PM2.5 to
total fine particle mass in most locations, and to the complexity of
secondary particle formation processes. A large number of possible
chemical reactions, often non-linear in nature, can convert gaseous
SO2, NOX, VOCs and NH3 to
PM2.5, making them precursors to PM2.5.\5\
Formation of secondary PM2.5 may also depend on atmospheric
conditions, including solar radiation, temperature, relative humidity,
and the interactions of precursors with preexisting particles and with
water and ice cloud or fog droplets.\6\
---------------------------------------------------------------------------

    \5\ EPA, Air Quality Criteria for Particulate Matter (EPA/600/P-
99/002aF, October 2004), Chapter 3.
    \6\ EPA, Regulatory Impact Analysis for the Final Revisions to
the National Ambient Air Quality Standards for Particulate Matter
(EPA-452/R-12-005, December 2012), p. 2-1.
---------------------------------------------------------------------------

    The EPA interprets the CAA to require states to evaluate sources of
all four PM2.5 precursors for regulation unless it provides
a demonstration establishing that it is either not necessary to
regulate a particular precursor in the nonattainment area at issue in
order to attain by the attainment date, or that emissions of the
precursor do not make a significant contribution to PM2.5
levels that exceed the standard. 40 CFR 51.1006 and 81 FR 58017. The
EPA has identified SO2, NOX, VOCs, and
NH3 as precursors to the formation of PM2.5. 40
CFR 51.1000. Accordingly, the attainment plan requirements
presumptively apply to emissions of direct PM2.5 and all
four precursor pollutants from all types of stationary, area, and
mobile sources, however, the presumption can be rebutted consistent
with CAA section 189(e) and the EPA's interpretation of the statute.
    Section 189(e) of the CAA requires that the control requirements
for major stationary sources of direct PM10 also apply to
major stationary sources of PM10 precursors, except where
the Administrator determines that such sources do not contribute
significantly to PM10 levels that exceed the standard in the
area. By definition, PM10 includes PM2.5. Section
189(e) contains the only express exception to the control requirements
under subpart 4 for sources of direct PM2.5 and
PM2.5 precursor emissions. Notwithstanding the fact that
section 189(e) explicitly addresses only major stationary sources, the
EPA interprets the CAA as authorizing it also to determine, under
appropriate circumstances, that regulation of specific PM2.5
precursors from other source categories in a given nonattainment area
are not necessary. See 81 FR 58018. If the EPA were to approve a
state's precursor demonstration, the state would not need to regulate
emissions of the precursor to meet the requirement to control emissions
from the inventory to attain as expeditiously as practicable, such as
the imposition of RACM/RACT on sources of such precursor emissions.
    The state has different options for demonstrating that a particular
precursor does not need to be controlled in the nonattainment area for
the purposes of the attainment plan: (1) A comprehensive precursor
demonstration to establish that the state does not need to address the
precursor in the attainment plan for purposes of the control strategy,
RFP, QMs and associated reports, contingency measures, MVEB, or
regional emissions analyses in transportation conformity
determinations, and/or (2) a major stationary source precursor

demonstration supporting a conclusion that one or more precursors do
not have to be controlled from existing major sources. 40 CFR 51.1006.
Both types of precursor demonstrations must include a concentration-
based analysis, in which the state evaluates the impact of each
precursor on ambient PM2.5 levels in the nonattainment area.
A concentration-based analysis may be sufficient for the EPA to approve
the demonstration, on a precursor-by-precursor basis. 40 CFR
51.1006(a)(1). If an impact of a particular precursor cannot be deemed
insignificant based upon the concentration based analysis, the state
also has the option of conducting a sensitivity-based analysis to show
that changes in the emissions of a particular precursor would not
result in significant changes in ambient PM2.5 in the area,
notwithstanding the fact that the volume of the precursor at issue is
large. 40 CFR 51.1006(a)(1)(iii). The EPA's Draft PM2.5
Precursor Demonstration Guidance (Draft Precursor Demonstration
Guidance) recommends calculating the precursor impact relative to
observed ambient data so that the results are applicable to measured
PM2.5 in the area.\7\
---------------------------------------------------------------------------

    \7\ The Precursor Demonstration Guidance is available at https://www.epa.gov/sites/production/files/2016-11/documents/transmittal_memo_and_draft_pm25_precursor_demo_guidance_11_17_16.pdf
---------------------------------------------------------------------------

2. Direct PM2.5 and Precursors in the Oakridge Update
    In the 2012 Oakridge Attainment Plan and the Oakridge Update, LRAPA
discusses the five pollutants that contribute to the mass of the
ambient PM2.5 (i.e., NH3, NOX,
SO2, VOCs, and direct PM2.5). LRAPA developed the
2012 Oakridge Attainment Plan before the EPA proposed a new
implementation rule in 2015 (80 FR 15340, March 23, 2015) and before
the EPA issued the Draft Precursor Demonstration Guidance in 2016. The
2012 Oakridge Attainment Plan therefore includes a variety of
information on precursor impacts on PM2.5 concentrations in
the Oakridge NAA. However, prior to submitting the Oakridge Update,
LRAPA was able to take advantage of the final PM2.5 SIP
Requirements Rule as well as the recommendations in the Draft Precursor
Demonstration Guidance during the public comment period.
    The Oakridge Update contains information necessary to evaluate a
comprehensive precursor demonstration for all sources of
SO2, NOX, NH3, and VOCs. It reports
speciated PM2.5 data from the WAC monitor that can be
compared to the recommended insignificance thresholds in the Draft
Precursor Demonstration Guidance as part of a concentration-based
analysis. These data are the results of the relative attainment test
methodology (speciated model attainment test or ``SMAT'') and are
representative of precursor concentrations for the baseline design
value of 39.5 [mu]g/m\3\ (Table 4). Values of 0.43 [mu]g/m\3\, 0.17
[mu]g/m\3\, and 0.17 [mu]g/m\3\ for SO2, NOX, and
NH3 respectively were compared to the recommended
insignificance threshold of 1.3 [mu]g/m\3\ in the Precursor
Demonstration Guidance. LRAPA used the monitored amount of sulfate to
assess the contribution from SO2 and the amount of ammonium
+ nitrate to assess the contributions from NOX and
NH3. LRAPA did not remove background concentrations of the
PM2.5 species for this analysis. More information on how the
relative calculations were applied can be found in the Oakridge Update
section II.D.

                                 Table 4--Concentrations of PM2.5 Species Used for the Speciated Modeled Attainment Test
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Elemental                                     Other primary
                Parameter                     Sulfate         Nitrate     Organic carbon      carbon           Water         Ammonium       particulate
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent.................................             1.1             0.4            88.4             7.6             1.4            0.03             1.1
[mu]g/m\3\..............................            0.43            0.16           34.46            2.95            0.54            0.01            0.44
--------------------------------------------------------------------------------------------------------------------------------------------------------

    LRAPA's VOC precursor demonstration examined both ambient and
modeled PM2.5 species data to help evaluate the formation of
secondary organic aerosols (SOA) from VOC emissions in the
nonattainment area. In the Oakridge Update, LRAPA did not directly
determine the impact of VOCs on PM2.5 from speciated
monitoring data alone because it is difficult to distinguish organic
carbon from direct PM2.5 and secondary organic carbon formed
from VOC chemistry.
    LRAPA presents several analyses involving observed chemical data, a
source apportionment analysis, and an independent modeling effort to
substantiate the demonstration. The PM2.5 data set from
2006-2010 at the WAC, which formed the basis for the baseline design
value, shows that exceedances of the standard only occur between
October 15 and February 28 (See Oakridge Update appendix 3, attachment
H). The same conclusion is valid for days with concentrations above 25
[mu]g/m\3\. The results of the concentration-based analysis in Table 4
show that species commonly associated with photochemistry, ammonium
sulfate and ammonium nitrate, occur in low concentrations during the
polluted days. In addition, LRAPA submitted a positive matrix
factorization (PMF) source apportionment study conducted by the EPA
Region 10 (See Oakridge Update appendix 3.E.2). That report concluded
primary emissions of wood smoke was responsible for about 75% of the
PM2.5 on polluted days above 25 [mu]g/m\3\. Additional
analysis was conducted by Portland State University in collaboration
with the ODEQ to better understand the secondary organic aerosols in
the Klamath Falls, Oregon airshed (See Oakridge Update, page 36). The
results showed that on wintertime days anthropogenic VOC emissions were
responsible for 3% of the observed PM2.5. After calibrating
this value to the Oakridge baseline design value of 39.5 [mu]g/m\3\,
LRAPA estimated that the anthropogenic VOC contribution to
PM2.5 is 1.17 [mu]g/m\3\ and asserted that the value is a
conservatively high value.
3. The EPA's Evaluation and Proposed Action: Pollutants Addressed
    The EPA confirmed that LRAPA performed a contribution-based
analysis for SO2, NOX, and NH3
according to section 3.1 of the Draft Precursor Demonstration Guidance,
with one exception. The guidance recommends that the NOX
contribution be calculated as the nitrate ion plus the ammonium
associated with nitrate, whereas LRAPA appears to have included all
ammonium in the calculation. Rounding to the hundredths decimal place,
the EPA calculated a contribution of 0.16 [mu]g/m\3\. This difference
is immaterial to LRAPA's conclusion, and LRAPA's calculation errs on
the conservative side. The contributions for SO2,
NOX, and NH3, 0.43 [mu]g/m\3\, 0.17 [mu]g/m\3\,
and 0.17 [mu]g/m\3\ respectively, are well below the recommended
contribution

threshold for the 24-hour PM2.5 NAAQS of 1.3 [mu]g/m\3\.
    For LRAPA's VOC precursor demonstration, the state agency presented
multiple analyses of observed data, source apportionment modeling, and
independent modeling. All of the analyses and modeling support the
conclusion that VOCs contribute only a small amount to PM2.5
in the Oakridge NAA and that this amount is 1.17 [mu]g/m\3\ or less, as
indicated by the Portland State University modeling. At the times where
there is substantial PM2.5 in Oakridge, the temperature is
low and the sun is relatively weak, which are less conducive to
secondary PM2.5 formation from VOCs. This conclusion is
supported by the fact that there is little secondary ammonium sulfate
and ammonium nitrate in the nonattainment area during periods of high
pollution (PM2.5 > 25 [mu]g/m\3\).
    While the Portland State University modeling was conducted for
Klamath Falls, both Klamath Falls and Oakridge were nonattainment for
the 24-hour PM2.5 standard for mainly wood smoke pollution
and with similar meteorology and atmospheric chemistry during periods
of high PM2.5. They are on opposite sides of the Oregon
Cascade Mountains, but they are only 115 miles apart and the modeling
used conservative meteorological conditions that would apply to both
locations. The modeling used emissions that are valid for 2008 in the
Klamath Falls nonattainment area and correspond to the base year
emission inventory for the Oakridge Update. The 2008 anthropogenic VOC
emissions for the Oakridge nonattainment area are 122 tons per year,
about 5% of that in the Klamath Falls nonattainment area. The EPA
believes that an analysis with Oakridge emissions would result in a
much lower PM2.5 contribution from VOCs, as argued by LRAPA
in the Oakridge Update (See page 36). All of the lines of evidence
supplied by LRAPA in the Oakridge Update are consistent with the
PM2.5 contribution from VOCs being 1.17 [mu]g/m\3\ or less.
This conservative value is below the recommended contribution threshold
for the 24-hour PM2.5 NAAQS of 1.3 [mu]g/m\3\.
    The EPA also examined an independent regional air quality modeling
effort for PM2.5, the Airpact model at Washington State
University.\8\ For 2015, this model estimates all PM2.5,
including secondary PM2.5 from anthropogenic VOC sources, in
12-km grid cells across the Northwest on a daily basis. For the period
of January, February, November, and December, corresponding to the
Oakridge PM2.5 season, the Airpact model predicts at most
0.16 [mu]g/m\3\ of PM2.5 species derived from anthropogenic
VOC emissions. While the model is not conducted in a way to be the
primary estimate of PM2.5 for the Oakridge nonattainment
area, its estimate of PM2.5 from anthropogenic VOC emissions
provides support for the low contribution estimated by Portland State
University for Klamath Falls and conservatively applied to Oakridge by
LRAPA.
---------------------------------------------------------------------------

    \8\ http://lar.wsu.edu/airpact/.
---------------------------------------------------------------------------

    Based on a review of the information provided by LRAPA, the EPA
believes LRAPA's methodology is appropriate for the area and that
LRAPA's concentration-based analyses are accurate and sufficiently
comprehensive to establish a precursor demonstration for
SO2, NOX, NH3, and VOCs. The EPA
proposes to approve LRAPA's precursor demonstrations for all existing
sources of SO2, NOX, NH3, and VOCs
within the Oakridge NAA. As a result, the EPA proposes to find it not
necessary to evaluate controls on sources of SO2,
NOX, NH3, and VOCs in the control strategy for
the Oakridge Update. We discuss LRAPA's evaluation of potential control
measures for direct PM2.5 in the following section.

C. Reasonably Available Control Measures/Reasonably Available Control
Technology

1. Requirements for RACM/RACT
    The general SIP planning requirements for nonattainment areas under
subpart 1 include CAA section 172(c)(1), which requires implementation
of all RACM, including RACT. The terms RACM and RACT are not further
defined within subpart 1, but past guidance has described ``reasonable
available'' controls as those controls that are technologically and
economically feasible, and necessary for attainment in a given area.
See 57 FR 13560. The provision explicitly requires that such measures
must provide for attainment of the NAAQS in the area covered by the
attainment plan.
    The SIP planning requirements for particulate matter nonattainment
areas in CAA subpart 4 require states to develop attainment plans that
implement RACM and RACT on appropriate sources within a nonattainment
area. Section 189(a)(1)(C) requires that states with areas classified
as Moderate nonattainment areas have SIP provisions to assure that RACM
and RACT level controls are implemented by no later than four years
after designation of the area. As with subpart 1, the terms RACM and
RACT are not specifically defined within subpart 4, and the provisions
of subpart 4 do not identify specific control measures that must be
implemented to meet the RACM and RACT requirements. However, past
policy has described RACM (including RACT) as those measures that are
technologically and economically feasible and needed for expeditious
attainment of the standard. 81 FR 58034. The PM2.5 SIP
Requirements Rule provides a process for developing an attainment plan
control strategy for purposes of meeting the RACM and RACT
requirements.\9\ See 40 CFR 51.1009.
---------------------------------------------------------------------------

    \9\ The development of the RACM and RACT requirements in the
PM2.5 Implementation Rule was informed by the EPA's
longstanding guidance in the General Preamble providing
recommendations for appropriate considerations for determining what
control measures constitute RACM and RACT for purposes of meeting
the statutory requirements of subpart 4. See 81 FR 58034.
---------------------------------------------------------------------------

    To meet the Moderate area control strategy requirements, a state
first needs to identify all sources of direct PM2.5 and
precursor emissions in the nonattainment area, consistent with common
emission inventory development practices and requirements. 40 CFR
51.1009(a)(1). Next, a state must identify existing and potential
control measures for each identified source or source category of
emissions. Id. at 51.1009(a)(2). The state's compilation of potential
control measures must be sufficiently broad to provide a basis for
identifying all technologically and economically feasible controls that
may be RACM or RACT. The state must identify potential control measures
for emissions of direct PM2.5 and each precursor from
relevant sources unless the state has provided an adequate
comprehensive demonstration for the nonattainment area at issue showing
that control of a particular precursor is not required, or provided an
adequate demonstration with respect to control of precursor emissions
from existing major stationary sources. Id. at 51.1009(a)(4)(i). For
any potential control measure identified, a state must evaluate the
technological and economic feasibility of adopting and implementing
such measure. Id. at 51.1009(a)(3). For purposes of evaluating
technological feasibility, a state may consider factors including but
not limited to operating processes and procedures, raw materials,
physical plant layout, and potential environmental impacts from the
adoption of controls. For purposes of evaluating economic feasibility,
a state may consider factors including but not limited to capital,
operating and

maintenance costs and the cost effectiveness of a measure (typically
expressed in cost per ton of reduction). Id. States should also
evaluate control measures imposed in other nonattainment areas as RACM
and RACT as part of this analysis.
    CAA section 110(a)(2)(A) provides generally that each SIP ``shall
include enforceable emission limitations and other control measures,
means or techniques . . . as well as schedules and timetables for
compliance, as may be necessary or appropriate to meet the applicable
requirement of the Act.'' Section 172(c)(6) of the CAA, which applies
specifically to nonattainment area plans, imposes comparable
requirements. Measures necessary to meet RACM/RACT and the additional
control measure requirements under section 172(c)(6) must be adopted by
the state in an enforceable form (57 FR 13541) and submitted to the EPA
for approval into the SIP under CAA section 110.
2. RACM/RACT Analysis in the Oakridge Update
    In the Oakridge Update, LRAPA evaluated and selected control
measures consistent with the process set forth in 40 CFR 51.1009 that
constitute RACM/RACT in the Oakridge NAA. Based on emissions inventory
information and other technical analyses, LRAPA first identified source
categories in the Oakridge NAA and associated emissions of
PM2.5 and its precursors. Based on the comprehensive
precursor demonstration for SO2, NOX,
NH3, and VOCs, LRAPA limited its RACM/RACT analysis to
direct PM2.5.
    LRAPA, in coordination with the Oakridge PM2.5 Advisory
Committee, developed a list of potential control measures for relevant
sources based on information compiled from various EPA guidance
documents, and information regarding controls that other states or the
EPA have identified as RACM or RACT in attainment plans in other
nonattainment areas. A full discussion of the RACM/RACT analysis and
control strategies are presented in the Oakridge Update Attainment
Strategies Section and Appendix 3, Attachment 3.3j. Table 5 provides a
chart of the RACM/RACT implemented for the Oakridge area and the
emission reductions modeled for each control strategy. All measures are
currently being implemented.
    LRAPA's approach to the RACM/RACT analysis targets emissions that
occur during the wintertime when stagnant air episodes occur and
concentrations of emissions accumulate, leading to exceedances of the
2006 24-hour PM2.5 NAAQS. The dominant source of
PM2.5 in Oakridge on worst-case winter days is wood
combustion in wood stoves and fireplaces (approximately 86% in the 2008
base year emissions inventory). Therefore, LRAPA identified strategies
in the Oakridge Update that focused primarily on RWC emission
reductions. The long-term permanent RWC strategies consist of a
mandatory curtailment program, a wood stove changeout program, the
Oregon and the EPA wood stove certification programs, the Oregon Heat
Smart Law, and Oregon State and federal transportation and fuel related
measures.
    LRAPA believes that the implementation of the mandatory curtailment
program was key in helping this area attain the 24-hour
PM2.5 standard. The curtailment program restricts wood
burning on red advisory days through Ordinance 920. Specifically, the
curtailment restricts combustion in residential solid fuel-fired
appliances on red advisory days when the forecast is for daily
PM2.5 to be greater than or equal to 25 [micro]g/m\3\. On
red advisory days the residents within the City of Oakridge are
prohibited from emitting visible emissions into the air from solid fuel
burning devices, unless the device is the sole source of heat or an
economic need exemption has been granted from the City Administrator.
The curtailment program is implemented through advisories forecasted by
LRAPA on a daily basis. The mandatory curtailment program was modeled
to provide the greatest PM2.5 emissions reductions in the
NAA of 7.1 [micro]g/m\3\.
    The wood stove changeout programs in Oakridge provided incentives
for homeowners to replace older uncertified wood stoves with newer,
cleaner certified wood stoves. Between 2009 and 2012, the changeout
program replaced 90 uncertified wood stoves in the Oakridge NAA. The
removal and destruction of the old wood stoves assures emissions
reductions are permanent. The changeouts are enforceable because a
statewide building code prohibits the installation of any uncertified
wood stove in the future. The Heat Smart Program, a statewide mandate
requiring removal of uncertified wood stoves at the time of home sale,
went into effect in 2010. This statewide rule closely mirrors the
existing requirement in the Oakridge ordinance. LRAPA is responsible
for the implementation of the Heat Smart Program in the Oakridge NAA,
however, the ODEQ is required to confirm residences where owners
removed or changed-out uncertified wood stoves upon home sale. Under
the rule, all uncertified devices on the property being sold must be
removed at the time of home sale. Three Heat Smart removals were
recorded and occurred prior to December 31, 2014. The changeout
programs described above are modeled to collectively provide
PM2.5 reductions in the NAA of 2.6 [micro]g/m\3\.
    LRAPA applied national and state measures to reduce mobile source
emissions, such as fuel economy standards and vehicle emissions
standards including Oregon Low Emission Vehicle regulations (LEV II).
These mobile measures are modeled to collectively provide direct
PM2.5 reductions in the NAA of 1.3 [micro]g/m\3\.
    There are two existing industrial sources in the Oakridge area that
are minor sources of PM2.5 emissions (a portable rock
crusher and concrete batch plant which shut down in 2014) which
together emit less than one ton per year of primary PM2.5
emissions. LRAPA explained that the air pollution control technology
installed on these sources are standard for the industry and would meet
RACT requirements. The rock crusher has water-spray controls and the
concrete plant had baghouse controls. Furthermore, the modeled impact
of these two sources is much less than 1 [micro]g/m\3\, even if they
were to operate at maximum permitted production rates valid in 2014.
LRAPA did not include any RACT requirement for these two minor sources
in the Oakridge Update because it was determined that RACT was not
needed to bring the area into attainment.

 Table 5--RACM/RACT Projected Air Quality Benefit for the Oakridge Area
------------------------------------------------------------------------
                                                           Modeled PM2.5
                                                           reductions on
                                                           a worst-case
                        RACM/RACT                           winter day
                                                            ([micro]g/
                                                               m\3\)

------------------------------------------------------------------------
Primary Control Measures:
     Mandatory curtailment program..............             7.1
     Wood stove changeout programs..............  ..............
     OR Heat Smart--uncertified wood stove                   2.6
     removal upon sale of home..........................
     OR and the EPA wood stove certification      ..............
     program............................................
     Transportation and Fuel Related Measures...             1.3
     Diesel Retrofits of school buses...........  ..............
     Oregon's Low Emission Vehicle Program......
     Increased Fuel Economy.....................
                                                         ---------------
        Total...........................................            11.0
Total Effective Reductions *............................            10.2
Ancillary Control Measures:
     Expanded public education..................               0
     Prohibits unseasoned (>20% moisture)         ..............
     firewood...........................................
     Firewood Seasoning Program.................  ..............
     Heating advisory extended from four to       ..............
     eight months.......................................
     Tighter restrictions on the wood stove       ..............
     curtailment exemption process......................
Supplemental Control Measures:
     Expanded field compliance..................  ..............
     Stricter wood stove curtailment program....             1.7
------------------------------------------------------------------------
* The individual emission reduction estimates in this table are derived
  from the modeled Future Design Value in 2015. Because the control
  strategies interact nonlinearly, the total effective reductions value
  is not a simple addition of the individual measures' benefits. When
  all control strategies are simulated together, their benefit is less
  than it would appear because, for instance, the curtailment ordinance
  has a smaller benefit when stoves have already been changed out to be
  cleaner.

    LRAPA expects the ancillary and supplemental control measures,
listed in Table 5, to increase compliance with regulations and
encourage behaviors that reduce emissions. The supplemental control
measures were implemented when it became clear the Oakridge NAA would
not attain the 2006 24-hr PM2.5 standard by the December 31,
2015 attainment date. The field compliance improvements were expanded
in October of 2015 with the hiring of a city code enforcement officer
to primarily focus on enforcing city ordinances during the winter
months.
    LRAPA asserts that while the expanded education and outreach is not
a permanent and enforceable measures in itself, the program to enhance
education, outreach, and public awareness is key to supporting the
implementation of the mandatory permanent and enforceable curtailment
programs, including increasing compliance rates with curtailments on
red advisory days. Further discussion of these measures can be found in
the Oakridge Update.
3. The EPA's Evaluation and Proposed Action: RACM/RACT
    The EPA proposes to approve the primary control measures listed in
Table 5 and sections of the City of Oakridge Ordinance 920 identified
below in Section IV Proposed Action, regulating wood and other solid
fuel burning in the Oakridge NAA. LRAPA appropriately followed a
process to analyze control measures and to select RACM/RACT level
controls for this specific NAA consistent with the requirement of
section 172(c)(1) and the procedures for Moderate NAAs identified at 40
CFR 51.1009. The result of this process was LRAPA's adoption and
implementation of a control strategy that includes the identified
technologically and economically feasible control measures for sources
of direct PM2.5 in the Oakridge NAA. Furthermore, consistent
with the requirements of 172(c)(6) and the procedures in 40 CFR
51.1009, LRAPA analyzed control measures to determine if there were any
other reasonable control measures and found none. The area attained the
2006 24-hr PM2.5 standard by the December 31, 2016 extended
attainment date, with a corresponding 2014-2016 design value of 31
[micro]g/m\3\ in 2016, so the advancement of attainment by one year, or
as expeditiously as possible, is no longer relevant.
    The EPA proposes to find that the Oakridge Update provides for the
implementation of RACM/RACT as required by CAA sections 189(a)(1)(C)
and 172(c)(1). The EPA's evaluation of the Oakridge Update indicates
that the control strategy includes permanent and enforceable
requirements and takes appropriate credit for emissions reductions from
those control measures. The EPA is proposing to approve LRAPA's
analysis and selection of RACM/RACT as meeting the requirements of
subparts 1 and 4.

D. Modeling

1. Requirements for Air Quality Modeling
    CAA section 189(a)(1)(B) requires each state with a Moderate
nonattainment area to submit a plan that includes, among other things,
either (i) a demonstration (including air quality modeling) that the
plan will provide for attainment by the applicable attainment date; or
(ii) a demonstration that attainment by such date is impracticable. For
model attainment demonstrations, the EPA's modeling requirements are in
40 CFR part 51, appendix W (82 FR 5182, January 17, 2017). The EPA's
guidance recommendations for model input preparation, model performance
evaluation, use of the model output for the attainment demonstration,
and modeling documentation are described in Draft Guidance for
Demonstrating Attainment of Air Quality Goals for

Ozone, PM2.5, and Regional Haze (Modeling Guidance).\10\
---------------------------------------------------------------------------

    \10\ The Modeling Guidance is available on EPA's SCRAM Web site,
Web page: https://www.epa.gov/scram/state-implementation-plan-sip-attainment-demonstration-guidance; direct link: https://www3.epa.gov/scram001/guidance/guide/Draft_O3-PM-RH_Modeling_Guidance-2014.pdf.
---------------------------------------------------------------------------

    Air quality modeling is used to establish emissions targets, the
combination of emissions of PM2.5 and PM2.5
precursors that the area can accommodate and still attain the standard,
and to assess whether the proposed control strategy is likely to result
in attainment of the relevant NAAQS. Air quality modeling is performed
for representative episodes in the past and compared to air quality
monitoring data collected during those episodes in order to determine
model performance. To project future design values, the model response
to emission reductions, in the form of relative response factors, is
applied on a chemical species-by-species basis to the baseline design
value, as implemented in the relative attainment test methodology and
described in the Modeling Guidance. The future year design value is
intended to estimate the projected 98th percentile of the 24-hour
average PM2.5 in the attainment year.
    In addition to a modeled attainment demonstration that focuses on
locations with an air quality monitor, the PM2.5 SIP
Requirements Rule recommends an additional test called an ``unmonitored
area analysis.'' This analysis is intended to ensure that a control
strategy leads to reductions in PM2.5 at other locations
that have no monitor, but might have base year and/or projected future
year ambient PM2.5 levels exceeding the standard. This is
particularly critical where the state and/or the EPA has reason to
believe that potential violations may be occurring in unmonitored
areas. Finally, as discussed in the Modeling Guidance, the EPA
recommends supplemental air quality analyses. These are used as part of
a weight of evidence analysis, in which the likelihood of attainment is
assessed by considering evidence other than the main air quality
modeling attainment test.
    For an attainment demonstration, a thorough review of all modeling
inputs and assumptions is especially important because the modeling
must ultimately support a conclusion that the plan (including its
control strategy) will provide for timely attainment of the applicable
NAAQS. The EPA recommends that states prepare a modeling protocol in
order to establish, prior to actual modeling, agreed upon procedures
with the appropriate EPA Regional Office for all phases of the modeling
analysis.
2. Air Quality Modeling in the Oakridge Update and the EPA's Evaluation
    LRAPA used a ``linear roll-forward'' model as the basis for
projecting future design values and the effect of control strategies.
In the Oakridge Update, this model is referred to as ``a proportional
roll-back/roll-forward'' and also as a ``rollback model''. We use the
term roll-forward here but are referring to the same model as in the
Oakridge Update. A standard roll-forward model assumes all sources
contribute to the WAC monitor in proportion to their weight in the
emissions inventory on a species-by-species basis. The model does not
explicitly treat chemistry leading to secondary PM2.5, but
as shown earlier, secondary PM2.5 is a very small percentage
of the total measured PM2.5 in Oakridge. As implemented in
the Oakridge Update, the roll-forward model assumes that the observed
concentrations of secondary species (secondary organic aerosol,
sulfate, nitrate, retained water, and ammonium) remain constant over
time. For secondary organic aerosol concentrations from VOC precursors,
LRAPA took Portland State University's results for Klamath Falls and
applied them to Oakridge.
    LRAPA developed multiple emission inventories for modeling
attainment, one for the 2008 base year and multiple for the 2015
attainment year. The inventories used for modeling are the worst-case
season day as defined in section III.A.2. Because of the simple form of
the roll-forward model and the small, homogeneous airshed of the
nonattainment area, the planning inventory for the nonattainment area
did not need to be expanded or modified for use as an inventory for
modeling. The projected 2015 attainment year inventory accounts for all
changes (i.e. vehicle fleet turnover, population changes) that were
expected to occur from 2008 through December 31, 2014. LRAPA then
applied each local control strategy to the projected 2015 modeling
inventory in isolation, and several or all strategies jointly, in order
to develop emission inventories for various emission control scenarios
in the 2015 attainment year. Once the emission inventories were
available, they were input into the relative attainment test to
estimate the future year design value.
    To calculate the projected 2015 PM2.5 design value,
LRAPA performed the SMAT methodology, as recommended in the EPA
modeling guidance. LRAPA used the ratio of attainment year (2015) to
base year (2008) modeling results to derive relative response factors
for organic carbon, elemental carbon, and ``other PM2.5''
(mainly crustal material). The relative response factor for organic
carbon does not account for changes in secondary organic aerosol, as
estimated by Portland State University, because secondary organic
aerosol is held constant between the base year and the attainment year
(2015). The concentration of secondary species sulfate, nitrate,
retained water, and ammonium are held constant between the base year
and the attainment year (2015), and thus those species have a response
factor of 1. These response factors were applied to concentrations of
chemical species in the baseline design value to produce an attainment
year design value. The results of this process are further discussed in
the Attainment Demonstration section E. Details of the analysis are
presented in Appendix 3, Attachment H of the Oakridge Update.
    LRAPA chose the 2006-2010 period for the baseline to represent
conditions before emission controls and calculated a baseline design
value of 39.5 [mu]g/m\3\. The concentrations of chemical species used
in the baseline design value were drawn from the monitoring data for
the top 25 percent most polluted wintertime days (in the first and
fourth quarters) when speciated monitoring was collected (between July
2009 and July 2011). Only the top 25 percent was used because there are
many cleaner days in the winter when the emission source mix and
contributions of PM2.5 to the monitor are not relevant for
air quality planning to meet the 24-hour PM2.5 standard. The
top 25 percent most polluted wintertime days best captured the days
with weather conditions and emissions patterns that occur when the
standard is exceeded. The average of the speciated concentrations of
the top 25 percent most polluted days were weighted to the observed
PM2.5 concentrations from the official regulatory data at
the WAC, such that the speciated PM2.5 data used for air
quality modeling (and for the precursor demonstration) are reflective
of the baseline design value of 39.5 [mu]g/m\3\. The technique was not
used for the second and third quarters because an examination of the
PM2.5 data from the baseline period 2006-2010 showed that
the data from the second and third quarters were too low to affect the
attainment year design value.
    The Oakridge Update also contains an unmonitored area analysis and
supplemental information as additional support for the modeling
demonstration. LRAPA conducted a saturation study in

2002-2003 in the town of Oakridge and in 2009-2010 for the Westfir
portion of the nonattainment area (See Oakridge Update appendix 3.A).
The area around the WAC had the highest concentrations of
PM2.5 in the winter when the air was polluted. LRAPA
submitted a positive matrix factorization (PMF) source apportionment
study conducted by the EPA Region 10 (See Oakridge Update appendix
3.E.2). That report concluded that primary emissions of wood smoke was
responsible for about 75% of the PM2.5 on polluted days
above 25 [mu]g/m\3\. In comparison, the base year emission inventory
attributes 80% of the primary PM2.5 on Worst Case Days to
wood smoke.
3. The EPA's Conclusions on Air Quality Modeling
    The model inputs, model design, modeling emission inventories,
supplemental information, and attainment test methodology are
appropriate for nonattainment planning and for an attainment
demonstration in the Oakridge NAA. The roll-forward model used by LRAPA
is not the standard attainment model used in larger areas and in areas
with significant secondary PM2.5. However, the roll-forward
model is well-suited to a nonattainment area that is on the scale of 5-
10 km and to an area where secondary PM2.5 is limited. The
extra complexity of a gridded photochemical model would add little
value and may be less transparent and more difficult to use for testing
out RACT/RACM measures. LRAPA's unmonitored area analysis shows that a
roll-forward model based on the data and location of the WAC is
appropriate because other parts of the nonattainment area experience
lower PM2.5 concentrations on polluted winter days. By
keeping the PM2.5 concentration of sulfate, nitrate,
retained water, and ammonium the same in 2015 as in 2008, LRAPA is
estimating a conservatively high attainment year design value because
the emission inventories show that precursor emissions to those
secondary species went down between 2008 and 2015, sometimes
substantially (See Tables 2 and 3 in section III.A.2). If secondary
PM2.5 reductions were included in the model, the modeled
future year design value would be slightly lower.
    The EPA is proposing to find that LRAPA's model adequately meets
the current EPA modeling requirements, and uses acceptable modeling
techniques to demonstrate attainment by December 31, 2015. The EPA also
proposes to find that the modeling is adequate for purposes of
supporting the control strategy analysis, RFP, and contingency
measures.

E. Attainment Demonstration

1. Requirements for Attainment Demonstration
    CAA section 189(a)(1)(B) requires that each Moderate area
attainment plan include a demonstration that the plan provides for
attainment by the latest applicable Moderate area deadline or,
alternatively, that attainment by the latest applicable attainment date
is impracticable. A demonstration that the plan provides for attainment
must be based on air quality modeling consistent with the EPA's
modeling regulations (51.1011(a)(2); 51.1011(a)(4)(ii); and 81 FR
58049). In SIP submissions to demonstrate attainment, the state should
document that its required control strategy in the plan represents the
application of RACM/RACT to existing sources.
    CAA section 188(c) states, in relevant part, that the Moderate area
attainment date ``shall be as expeditiously as practicable but no later
than the end of the sixth calendar year after the area's designation as
nonattainment.'' For the 2006 24-hour PM2.5 NAAQS, effective
December 14, 2009, the applicable Moderate area attainment date under
section 188(c) for the Oakridge NAA is as expeditiously as practicable,
but no later than December 31, 2015.
    In addition, the EPA's August 24, 2016, PM2.5 SIP
Requirements Rule provides that a state's modeled attainment
demonstration needs to establish that an area will attain the NAAQS by
the projected attainment date. Practically speaking, this is considered
satisfied by the modeling showing that the 98th percentile is below the
standard for the attainment year (81 FR 58010, at page 58054). The EPA
authorizes this approach because of the potential availability of
extensions of the attainment date under relevant provisions of the CAA.
In other words, if ambient data show attainment-level concentrations in
the applicable statutory attainment year, a state may be eligible for
up to two 1-year extensions of the attainment date. See 40 CFR 51.1005.
Using this provision, a state may be able to attain the NAAQS by the
December 31, 2016 extended attainment date, even if the measured design
value (a 3-year average) for an area does not meet the NAAQS by the end
of the 6th calendar year after designation. For this reason, the EPA's
PM2.5 SIP Requirements Rule indicates that it is acceptable
for a state to model air quality levels for the final statutory
attainment year in which the area is required to attain the standard
(in this case 2015).
2. Attainment Demonstration in the Oakridge Update
    In the Attainment Demonstration section of the Oakridge Update,
LRAPA described how its chosen control strategies would provide the
emissions reductions needed to demonstrate attainment by December 31,
2015. The majority of projected control strategy air quality benefits
came from the wood smoke curtailment program, the wood stove changeout
program, and the Heat Smart program. A more detailed discussion of
these strategies can be found in section III. C. RACT/RACM above.
    Table 6 lists the control strategies, the modeled PM2.5
benefit in the attainment year from each major control strategy, and
the attainment year design value from all control strategies
implemented together. LRAPA estimated the total effective emissions
reductions from the adopted control strategy in the Oakridge Update
would result in a 10.2 [micro]g/m\3\ reduction from the baseline design
value of 39.5 [mu]g/m\3\ at the WAC monitor resulting in a 2015
attainment year design value of 29.3 [micro]g/m\3\. The design value
represents the modeled 98th percentile for 2015 based on controls in
place by December 31, 2014.

 Table 6--2015 Attainment Demonstration Strategies for the Oakridge Area
------------------------------------------------------------------------
                                                              Projected
                                                             air quality
                     Control strategies                        benefit
                                                              ([micro]g/
                                                                m\3\)
------------------------------------------------------------------------
Baseline Design Value......................................         39.5
Primary Control Measures (Table 5 contains a detailed list          10.2
 of control strategies)....................................

Future Design Value 2015...................................         29.3
------------------------------------------------------------------------
* The individual emission reduction estimates in this table are derived
  from the modeled Future Design Value in 2015. The air quality benefit
  for the control measures are presented in Table 5. Because the control
  strategies interact nonlinearly, the final design value is not a
  simple subtraction of the individual measures' benefits from the
  baseline design value. When all control strategies are simulated
  together, their benefit is less than it would appear because, for
  instance, the curtailment measure has a smaller benefit when stoves
  have been changed out to be cleaner.

3. The EPA's Evaluation and Proposed Action: Attainment Demonstration
    We have evaluated the Oakridge attainment demonstration, supporting
air quality modeling, supplemental analyses, and RACM/RACT control
strategy analyses which address the adoption of all reasonable
measures. The EPA's evaluation of the Oakridge Update indicates that
the control strategy includes permanent and enforceable requirements
and takes appropriate credit for emissions reductions from those
control measures. We are proposing to approve the Oakridge attainment
demonstration for the area. LRAPA showed that emission controls were in
place in order to demonstrate attainment by December 31, 2015 for the
2006 PM2.5 NAAQS. The requirement to demonstrate that
attainment could not be advanced by a year or more by implementing
additional measures as expeditiously as practicable was met in that
there were no additional reasonable control measures available for
implementation.
    The area needed to identify at least 4.1 [micro]g/m\3\ of
reductions to get from the baseline design value of 39.5 [mu]g/m\3\ to
attain the 2006 PM2.5 NAAQS. With a 2014-2016 design value
of 31 [micro]g/m\3\, the emissions reductions from the implementation
of the adopted permanent and enforceable measures of 10.2 [micro]g/m\3\
are sufficient to provide a buffer below the 35 [micro]g/m\3\ standard
and demonstrate attainment. Recent monitoring data demonstrates
attainment with the NAAQS and that the plan was effective.
    Finally, the unmonitored area analysis confirms that the WAC is the
highest neighborhood-scale location in the nonattainment area on
polluted winter days. Given the high contribution of wood smoke to high
PM2.5 levels at the WAC monitor, the relatively uniform
distribution of emissions within the nonattainment area, and the focus
of control measures on wood burning, it is reasonable to conclude that
demonstrating attainment at the WAC monitor assures attainment
elsewhere in the nonattainment area.

F. Reasonable Further Progress (RFP) and Quantitative Milestones (QM)

1. Requirements for RFP and QMs
    CAA section 172(c)(2) requires nonattainment area plans to provide
for RFP. In addition, CAA section 189(c) requires PM2.5
nonattainment area SIPs to include QMs to be achieved every 3 years
until the area is redesignated to attainment and which demonstrate RFP.
CAA section 171(1) defines RFP as ``such annual incremental reductions
in emissions of the relevant air pollutant as are required by [Part D]
or may reasonably be required by the Administrator for the purpose of
ensuring attainment of the applicable [NAAQS] by the applicable date.''
Neither subpart 1 nor subpart 4 require that a set percentage of
emissions reductions be achieved in any given year for purposes of
satisfying the RFP requirement for PM2.5 NAAQS. Because RFP
is an annual emission reduction requirement and the QMs are to be
achieved every 3 years, when a state demonstrates compliance with the
QM requirement, it provides an objective evaluation of RFP that has
been achieved during each of the relevant 3 years. 40 CFR
51.1013(a)(1)(ii).
    An attainment plan for a PM2.5 nonattainment area must
include an RFP analysis that demonstrates that sources in the area will
achieve such annual incremental reductions in emissions of direct
PM2.5 and PM2.5 precursors as are necessary to
ensure attainment as expeditiously as practicable. 40 CFR 51.1012(a).
The RFP analysis must include a schedule for implementation of the
control measures and provide projected emissions from these measures
for each applicable milestone year. Id. at 51.1012(a)(1)-(2). At a
minimum, QMs for a Moderate area attainment plan must track progress
achieved in implementing RACM/RACT and additional reasonable control
measures by each milestone date. Therefore, timely implementation of
the control measures that achieve the emissions reductions comprising
the RFP plan provides a means for satisfying the QM requirement.
    The CAA does not specify the starting point for counting the 3-year
periods for QMs under CAA section 189(c). However, the EPA's
longstanding interpretation of the CAA is that the first QM should fall
3 years after the latest date on which the state should have submitted
the attainment plan. For the 2006 PM2.5 NAAQS, the EPA set
QMs to be achieved no later than 3 years after December 31, 2014, and
every 3 years thereafter until the QM date that falls within 3 years
after the applicable attainment date. 40 CFR 51.1013(a)(4).
Accordingly, the only QM date for the Oakridge NAA Moderate attainment
plan must be met no later than December 31, 2017 (3 years after
December 31, 2014), with additional QM dates to be identified in the
Serious attainment plan if needed.
2. RFP and QMs in the Oakridge Update
    The Oakridge Update identifies direct PM2.5 emission
reductions achieved as a result of progressively implemented control
strategies. These control strategies were implemented from 2008 through
2016 and continue to be in effect. LRAPA provided a table in the
Oakridge Update that listed the PM2.5 control strategies,
the implementation timeframes and direct PM2.5 emissions
reductions realized. Table 7 summarizes this information.

                     Table 7--Summary of PM2.5 Air Quality Improvements From RWC Strategies
----------------------------------------------------------------------------------------------------------------
                                                                     Reductions on worst case
                                                                     winter days- direct PM2.5
                          RWC strategy                           --------------------------------   Time period
                                                                      lb/day       [micro]g/m\3\
----------------------------------------------------------------------------------------------------------------
Changeouts......................................................              38             2.6       2009-2014
Curtailment Program.............................................             107             7.1       2009-2014
Strengthened Curtailment Program................................              25             1.7       2015-2016
----------------------------------------------------------------------------------------------------------------

    LRAPA provided a projected year emissions inventory and modeled
concentrations for 2016 which is within the three-year period after the
applicable attainment date (3 years after December 31, 2014). The 2016
projected emissions inventory and modeling reflects the contingency
measures implemented in 2015 in order to meet the 2006 24-hr
PM2.5 standard by the December 31, 2016 extended attainment
date. The demonstrated impact of these measures (stronger curtailment
program and enhanced enforcement on more red advisory days) showed a
reduction in PM2.5 emissions by an additional 25 lb/day and
a reduction in PM2.5 concentrations on worst case days by an
additional 1.7 [micro]g/m\3\. The modeled PM2.5
concentration for 2016 was 27.5 [micro]g/m\3\ and the actual 98th
percentile for 2016 was 21.7 [micro]g/m\3\.
    In the Oakridge Update, LRAPA outlined their plan to submit to the
EPA, by June 30, 2017, a Quantitative Milestone report and an annual
RFP update in the event the standard was not attained by December 31,
2016. The QM report would explain ongoing progress in implementing the
required control measures in the area until attainment of the 2006 24-
hr PM2.5 NAAQS was achieved.
3. The EPA's Evaluation and Proposed Action: RFP and QMs
    The EPA proposes to find that the Oakridge Update adequately meets
both the RFP and QM requirements for this area as specified in the CAA
and the PM2.5 SIP Requirements Rule. Even though LRAPA did
not label the information we relied on to make our determination as RFP
and QM, it was clear that attainment was achieved incrementally and the
area substantively met the RFP and QM requirements based on other data
gathered from their submission.
    As of the time the state submitted the Oakridge Update, the area
was attaining the 2006 24-hour PM2.5 NAAQS. After reviewing
the Oakridge Update, the EPA identified that the control strategies
were implemented on time and achieved incremental emission reductions
that resulted in attainment of the 2006 24-hour PM2.5 NAAQS
by the extended attainment date. The Oakridge Update provides
sufficient data to identify emission reductions necessary for
quantifying reasonable progress towards demonstrating attainment. The
key control strategies for attainment were implemented and emissions
reductions achieved during the period of nonattainment as a result of
measures implemented in the area. These measures collectively
contributed to the attainment of the 2006 PM2.5 NAAQS by
December 31, 2016. As a result, the area needs no further annual
incremental emissions reductions.
    The EPA finds that the adopted measures listed in Table 7 are being
implemented and sufficient incremental reductions in emissions occurred
over the attainment period to satisfy the RFP requirement. Further, the
EPA concludes that the accounting of control measure implementation and
the resultant emissions reductions satisfy the QM requirement for the
area. For these reasons, the EPA proposes to approve the submitted
Oakridge Update as meeting both the RFP and QM requirements.
    The requirement to submit and achieve milestones does not continue
after attainment of the NAAQS. Although section 189(c) states that
revisions shall contain milestones which are to be achieved until the
area is redesignated to attainment, such milestones are designed to
show reasonable further progress ``toward attainment by the applicable
attainment date,'' as defined by section 171. Thus, it is clear that
once the area has attained the standard, a demonstration to satisfy the
QM requirement is no longer necessary. This interpretation is supported
by language in section 189(c)(3), which mandates that a state that
fails to achieve a milestone must submit a plan that assures that the
state will achieve the next milestone or attain the NAAQS if there is
no next milestone.

G. Contingency Measures

1. Requirements for Contingency Measures
    Under CAA section 172(c)(9), PM2.5 plans must include
contingency measures to be implemented if an area fails to meet RFP or
fails to attain the PM2.5 standards by the applicable
attainment date. The purpose of contingency measures is to continue
progress in reducing emissions during the period while a state is
revising its SIP to address a failure, such as a failure to meet a QM
requirement or failure to attain. The principal considerations for
evaluating contingency measures are:
     Contingency measures must be fully adopted rules or
control measures that are ready to be implemented quickly upon failure
to meet RFP or failure of the area to meet the NAAQS by its attainment
date.
     The SIP must contain trigger mechanisms for the
contingency measures, specify a schedule for implementation, and
indicate that the measures will be implemented without further action
by the state or by the EPA. In general, we expect all actions needed to
affect full implementation of the measures to occur within 60 days
after the EPA notifies the state of a failure.
     The contingency measures shall consist of control measures
that are not otherwise included in the control strategy or that achieve
emissions reductions not otherwise relied upon in the control strategy
for the area.
     The measures should provide for emissions reductions
equivalent to approximately one year of reductions needed for RFP
calculated as the overall level of reductions needed to demonstrate
attainment divided by the number of years from the base year to the
attainment year. 81 FR 58066.
2. Contingency Measures in the Oakridge Update
    In 2014, LRAPA determined the Oakridge NAA was not making
reasonable further progress toward attaining the 2006 24-hr
PM2.5 NAAQS by the December 31, 2015, attainment date. In
addition to requesting a 1-year

extension of the 2015 attainment date, LRAPA and the City of Oakridge
triggered the following contingency measures contained in the 2012
p.m.2.5 SIP submittal.\11\
---------------------------------------------------------------------------

    \11\ These contingency measures were previously disapproved by
EPA (81 FR 72714) because the regulatory text of the contingency
measures (Oakridge Ordinance 914) had not been included as a part of
that SIP submission.
---------------------------------------------------------------------------

     A stricter advisory program, reducing the red advisory
threshold by 5 [mu]g/m\3\, from 30 [mu]g/m\3\ to 25 [mu]g/m\3\ thereby
potentially increasing the average number of red advisory days by 5
days per year--adopted into Oakridge Ordinance 920.
     Expanding field compliance with a dedicated Oakridge
Police Department compliance officer.
    The contingency measures for stronger enforcement on more red
advisory days were modeled and projected to reduce the future year
design value by 1.7 [micro]g/m\3\, which is greater than the one year
of RFP reductions of 0.7 [micro]g/m\3\ needed per year to demonstrate
attainment by the attainment year.\12\ These contingency measures are
fully implemented, submitted as part of the permanent and enforceable
control strategy in the Oakridge Update (Oakridge Ordinance 920) and
have helped the area achieve attainment by 2016.
---------------------------------------------------------------------------

    \12\ Other provisions were adopted in Ordinance 920, but weren't
relied upon as contingency measures to establish the one year of RFP
reduction needed per year to demonstrate attainment by the
attainment year.
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    In order to address the next potential triggering event, failure to
attain the applicable standard, LRAPA identified two additional
contingency measures and submitted them as part of the Oakridge Update.
In accordance with basic requirements for valid contingency measures,
these two measures are not required to meet other attainment plan
requirements and are not relied on in the control strategy. The
contingency measures in the Oakridge Update are:
     An increase in the number of red advisory days each
winter. LRAPA projects that by reducing the red advisory thresholds by
3 [mu]g/m\3\, from 25 [mu]g/m\3\ to 22 [mu]g/m\3\, the average number
of potential red advisory days will increase by three to five
additional days per year; and
     Prohibition of fireplace use on yellow advisory days (in
addition to the existing prohibition on red advisory days).
    These contingency measures were adopted as part of the City of
Oakridge Ordinance 920. In accordance with basic requirements for valid
contingency measures, they will go into effect for the October 1, 2017,
wood heating season with minimal further action by the state or the EPA
in response to a triggering event; in this case the measures adopted by
LRAPA will automatically go into effect if the EPA makes a finding that
Oakridge fails to attain by the applicable attainment date.
Implementation of the contingency measures are projected to reduce the
future year design value by 2.8 [micro]g/m\3\, which is greater than
the one year of RFP reductions of 0.7 [micro]g/m\3\ needed per year to
demonstrate attainment by the attainment year.
3. The EPA's Evaluation and Proposed Action: Contingency Measures
    The Oakridge Update includes contingency measures that would take
effect upon failure of the Oakridge NAA to attain by the applicable
attainment date, December 31, 2016. The Oakridge NAA monitored
attainment of the 2006 24-hour PM2.5 NAAQS by the applicable
attainment date. In this notice, the EPA is proposing to approve the
contingency measures included within the Oakridge Ordinance 920 as
meeting the requirements of section 176(c) of the CAA.

H. Motor Vehicle Emissions Budgets

1. Requirements for the Motor Vehicle Emissions Budgets
    Section 176(c) of the CAA requires Federal actions in nonattainment
and maintenance areas to ``conform to'' the goals of SIPs. This means
that such actions will not cause or contribute to violations of a
NAAQS, worsen the severity of an existing violation, or delay timely
attainment of any NAAQS or interim milestones. Actions involving
Federal Highway Administration (FHWA) or Federal Transit Administration
(FTA) funding or approval are subject to the transportation conformity
rule (40 CFR part 93, subpart A) as well as the Oregon transportation
conformity SIP which cites the national rule (77 FR 60627). Under this
rule, metropolitan planning organizations (MPOs) in nonattainment and
maintenance areas coordinate with state air quality and transportation
agencies, the EPA, the FHWA and the FTA to demonstrate that their long-
range transportation plans and transportation improvement programs
(TIPs) conform to applicable SIPs. This demonstration is typically
determined by showing that estimated emissions from existing and
planned highway and transit systems are less than or equal to the motor
vehicle emissions budgets (MVEB) contained in a SIP.
    The emissions inventories should identify MVEB for the attainment
year and each RFP milestone year for direct PM2.5 and
NOX. The MVEB should also reflect VOC, SO2, and
NH3, if transportation-related emissions of these precursors
have been found to contribute significantly to the PM2.5
nonattainment problem (40 CFR 93.102(b)(2)(iv)). 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. See 40 CFR 93.102(b) and 93.122(f) and the
conformity rule at https://nepis.epa.gov/Exe/ZyPDF.cgi/P100E7CS.PDF?Dockey=P100E7CS.PDF.
2. Motor Vehicle Emissions Budgets in the Oakridge Update
    Oakridge is considered an isolated rural nonattainment area, so
transportation conformity under 40 CFR 93.109(g) is only needed when a
non-exempt federally-funded project is funded or approved. The Oakridge
Update includes budgets for direct PM2.5 for 2015. The
budget was calculated with the assistance of the ODEQ using the
MOVES2014a vehicle emissions model and was executed with locally
developed inputs representative of wintertime calendar year 2015
conditions. The mobile source emissions were modeled to steadily
decrease between 2008 and 2015 as a result of cleaner vehicles and
cleaner fuels. Secondary particulate is a minor contributor to the
Oakridge PM2.5 air pollution concentrations on worst winter
days as summarized above in section III. B. Therefore, the Oakridge
2015 MVEB of 22.2 lb/day for direct PM2.5 is a sum of
primary exhaust, brake wear and tire wear.
3. The EPA's Evaluation and Proposed Action: Motor Vehicle Emissions
Budgets
    For MVEB to be approvable, they must meet, at a minimum, the EPA's
adequacy criteria (40 CFR 93.118(e)(4)). In this notice, the EPA is
proposing to approve the comprehensive precursor demonstration for
SO2, NOX, NH3, and VOCs (See section
III. B) and proposing to find that the state does not need to address
precursors in the Oakridge Update for purposes of the MVEB, or regional
emissions analyses in transportation conformity determinations. The EPA
has reviewed the MVEB and found it to be consistent with the attainment
of the 2006 24-hour PM2.5 NAAQS and that it met the

criteria for adequacy and approval (82 FR 26090, June 6, 2017). The EPA
proposes to approve the 2015 MVEB of 22.2 lb/day for direct
PM2.5 for the 24-hour PM2.5 NAAQS for the
Oakridge NAA. As a clarification, only the 2015 MVEB in the submittal
is applicable to the attainment plan and only the 24-hour budget will
be used for conformity purposes. As such, the EPA believes that these
motor vehicle emissions meet applicable requirements for such budgets
for purposes of the 2006 24-hour PM2.5 NAAQS for
transportation conformity purposes. If approved as proposed, this
action will lift the conformity freeze put in place as of November 21,
2016 (40 CFR 72714).

IV. Proposed Action

    The EPA proposes to:
     Determine that the Oakridge area attained the 2006 24-hour
PM2.5 NAAQS by the December 31, 2016 attainment date as
demonstrated by quality-assured and quality-controlled 2014-2016
ambient air monitoring data.
     Make a clean data determination (CDD) in accordance with
the EPA's clean data policy. In the event that EPA determines in its
final action that the Oakridge Update should not be approved, the Clean
Data Determination would suspend Oregon's obligation to submit a
revised SIP to address the attainment planning requirements related to
attainment of the 2006 24-hour PM2.5 NAAQS, and would toll
the FIP and sanctions clocks that were started by the EPA's prior
disapprovals as long as the area remains in attainment.
     Fully approve the remaining elements of the Oakridge
Update as meeting the requirements section 110(k) of the CAA.
Specifically, the EPA has determined the Oakridge Update meets the
substantive statutory and regulatory requirements for base year and
projected emissions inventories for the nonattainment area, and an
attainment demonstration with modeling analysis and imposition of RACM/
RACT level emission controls, RFP plan, QMs, and contingency measures.
Therefore, the EPA is proposing to approve these elements.\13\ The EPA
is also proposing to approve a comprehensive precursor demonstration
for VOCs, SO2, NOX, and NH3. The EPA
is also proposing to approve the 2015 MVEB of 22.2 lb/day for direct
PM2.5.
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    \13\ It is important to note, the 2016 Oakridge Update includes
the complete 2012 Oakridge Attainment Plan which was previously
partially approved, partially disapproved (81 FR 72714). In this
action, the EPA is taking no action on the following elements of
2012 Oakridge Attainment Plan included in Appendix 3 of the 2016
Oakridge Update; the 2012 Oakridge PM2.5 Attainment Plan
and associated appendices F1, F6 and K. These elements are
considered informational elements, not essential for making
decisions on the 2016 Oakridge Update. On February 24, 2016, ODEQ
withdrew appendices F2 and F3 from the Oakridge PM2.5
Attainment Plan submittal and clarified that they were provided for
informational purposes only.
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     Approve, and incorporate by reference, the following
sections in the City of Oakridge Ordinance 920: Section 1 Definitions;
Section 2(1) Curtailment; Section 2(2) Prohibited materials; Section 3
Solid Fuel Burning Devices Upon Sale of the Property; Section 4 Solid
Fuel Burning Devices Prohibited; Section 5 Solid Fuel Burning Devices
Exemptions; Section 7 Contingency Measures.

V. Incorporation by Reference

    In this rule, we are proposing to include in a final rule
regulatory text that includes incorporation by reference. In accordance
with requirements of 1 CFR 51.5, we are proposing to incorporate by
reference the provisions described above in Section IV. Proposed
Action. The EPA has made, and will continue to make, these documents
generally available electronically through https://www.regulations.gov
and/or in hard copy at the appropriate EPA office (see the ADDRESSES
section of this preamble for more information).

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP
submission 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 submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
proposed action merely approves state law as meeting Federal
requirements and does not impose additional requirements beyond those
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);
     Is not an Executive Order 13771 (82 FR 9339, February 2,
2017) regulatory action because SIP approvals are exempted under
Executive Order 12866;
     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 the 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).
    The SIP is not approved to apply on any Indian reservation land or
in any other area where the EPA or an Indian tribe has demonstrated
that a tribe has jurisdiction. In those areas of Indian country, the
rule does not have tribal implications as specified by Executive Order
13175 (65 FR 67249, November 9, 2000), nor will it impose substantial
direct costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Particulate
matter, Reporting and recordkeeping requirements, Sulfur oxides,
Volatile organic compounds.

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

    Dated: November 1, 2017.
Michelle L. Pirzadeh,
Acting Regional Administrator, Region 10.
[FR Doc. 2017-24539 Filed 11-13-17; 8:45 am]
 BILLING CODE 6560-50-P