[Federal Register Volume 83, Number 92 (Friday, May 11, 2018)]
[Proposed Rules]
[Pages 21976-21983]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-09992]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R10-OAR-2017-0582; FRL-9977-96--Region 10]


Air Plan Approval; ID, Pinehurst PM10 Redesignation, Limited 
Maintenance Plan; West Silver Valley 2012 Annual PM2.5 Emission 
Inventory

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: On September 29, 2017, the Idaho Department of Environmental 
Quality (IDEQ) submitted a redesignation request and limited 
maintenance plan (LMP) for particulate matter with an aerodynamic 
diameter less than or equal to ten micrometers (PM10) for 
the PM10 National Ambient Air Quality Standard (NAAQS) 
developed for the Pinehurst PM10 Nonattainment Area (NAA) 
and Pinehurst PM10 Expansion Nonattainment Area (NAA). The 
redesignation request asserts that the area meets the Clean Air Act 
(CAA) requirements for redesignation identified in section 
107(d)(3)(E). This limited maintenance plan for these contiguous 
nonattainment areas addresses maintenance of the PM10 
standard for a ten-year period beyond redesignation. The Environmental 
Protection Agency (EPA) proposes to approve this IDEQ Implementation 
Plan (SIP) revision. The EPA also proposes to approve the September 15, 
2013, high wind exceptional event at the Pinehurst monitoring station. 
Additionally, the EPA is proposing to approve the emissions inventory 
for the West Silver Valley annual PM2.5 NAA.

DATES: Written comments must be received on or before June 11, 2018.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R10-
OAR-2017-0582, at http://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 whose disclosure is restricted by statute. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or 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 http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Justin Spenillo, Air Planning Unit, 
Office of Air and Waste (OAW-150), Environmental Protection Agency, 
Region 10, 1200 Sixth Ave., Suite 900, Seattle, WA 98101; telephone 
number: 206-553-6125, email address: [email protected].

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

Table of Contents

I. This Action
II. Background
    A. PM10 NAAQS
    B. Pinehurst PM10 NAA and Planning Background
III. Requirements for Redesignation
    A. CAA Requirements for Redesignation of Nonattainment Area
    B. The LMP Option for PM10 Nonattainment Areas
    C. Conformity Under the LMP Option
IV. Review of the Idaho Submittal Addressing the Requirements for 
Redesignation and LMPs
    A. Has the Pinehurst PM10 NAA attained the applicable 
NAAQS?
    B. Does the Pinehurst PM10 NAA have a fully approved 
SIP under section 110(k) of the CAA?
    C. Has the IDEQ met all applicable requirements under section 
110 and Part D of the CAA?
    D. Has the IDEQ demonstrated that the air quality improvement is 
due to permanent and enforceable reductions?
    E. Does the area have a fully approved maintenance plan pursuant 
to section 175A of the CAA?
    F. Has the IDEQ demonstrated that the Pinehurst PM10 
NAA qualifies for the LMP Option?
    G. Does the IDEQ have an approved attainment emissions inventory 
which can be used to demonstrate attainment of the NAAQS?
    H. Does the LMP include an assurance of continued operation of 
an appropriate EPA-approved air quality monitoring network, in 
accordance with 40 CFR part 58?
    I. Does the plan meet the clean air act requirements for 
contingency provisions?
    J. How is conformity treated under a limited maintenance plan?
V. 2013 p.m.10 High Wind Exceptional Event
VI. West Silver Valley 2012 Annual PM2.5 Emission 
Inventory

[[Page 21977]]

    A. Requirements for Emissions Inventories
    B. West Silver Valley PM2.5 Base Year Emissions 
Inventory
    C. EPA's Evaluation
VII. Proposed Action
VIII. Statutory and Executive Order Reviews

I. This Action

    The EPA is proposing to approve the limited maintenance plan (LMP) 
submitted by the Idaho Department of Environmental Quality (IDEQ) on 
September 29, 2017, for the Pinehurst PM10 Nonattainment 
Area (NAA) and Pinehurst PM10 Expansion NAA and to 
concurrently redesignate the areas to attainment for the 
PM10 National Ambient Air Quality Standard (NAAQS). 
Throughout this notice, Pinehurst PM10 NAA shall refer to 
both the original Pinehurst PM10 NAA and Pinehurst 
PM10 Expansion NAA unless noted otherwise. The EPA has 
reviewed air quality data for the area and determined that the 
Pinehurst NAA attained the PM10 NAAQS by the required 
attainment date, and that monitoring data continue to show attainment. 
The EPA is proposing to approve exclusion of data from a high wind 
exceptional event on September 15, 2013, that impacted PM10 
values at the Pinehurst monitor as they are needed to meet the LMP 
criteria. Separately, the EPA is proposing to approve the base year 
emission inventory for the West Silver Valley (WSV) PM2.5 
NAA in the Silver Valley, Idaho.

II. Background

A. PM10 NAAQS

    ``Particulate matter,'' also known as particle pollution or PM, is 
a complex mixture of extremely small particles and liquid droplets. The 
size of particles is directly linked to their potential for causing 
health problems. The EPA is concerned about particles that are 10 
micrometers in diameter or smaller because those are the particles that 
generally pass through the throat and nose and enter the lungs. Once 
inhaled, these particles can affect the heart and lungs and can cause 
serious adverse health effects. People with heart or lung diseases, 
children and older adults are the most likely to be affected by 
particle pollution exposure. Healthy individuals may also experience 
temporary symptoms from exposure to elevated levels of particle 
pollution.
    On July 1, 1987, the EPA promulgated a NAAQS for PM10 
(52 FR 24634). The EPA established a 24-hour standard of 150 [micro]g/
m\3\ and an annual standard of 50 [micro]g/m\3\, expressed as an annual 
arithmetic mean. The EPA also promulgated secondary PM10 
standards that were identical to the primary standards. In a rulemaking 
action dated October 17, 2006, the EPA retained the 24-hour 
PM10 standard but revoked the annual PM10 
standard (71 FR 61144, effective December 18, 2006).

B. Pinehurst PM10 NAA and Planning Background

    On July 1, 1987, the EPA promulgated the PM10 NAAQS (52 
FR 24634) and on August 7, 1987, the EPA identified the Pinehurst area 
as a ``Group I'' area with a strong likelihood of violating the NAAQS 
(52 FR 29383). On March 15, 1991, the EPA published a notice announcing 
that the Pinehurst area had been designated a PM10 NAA upon 
the November 15, 1990 enactment of the 1990 CAA Amendments. In this 
notice, the EPA identified that the IDEQ needed to develop and submit 
by November 15, 1991, a plan that would bring the area into attainment 
by no later than December 31, 1994 (56 FR 11101). On November 6, 1991, 
the Pinehurst PM10 NAA, which included the City of 
Pinehurst, was classified as moderate under sections 107(d)(4)(B) and 
188(a) of the CAA (56 FR 56694), and it had an attainment date of no 
later than December 31, 1994. On December 21, 1993, the EPA designated 
the Pinehurst PM10 Expansion NAA, a contiguous area to the 
south of the City of Pinehurst and the existing Pinehurst 
PM10 NAA; the action became effective January 20, 1994 (58 
FR 67334). The Pinehurst Expansion area had an attainment date no later 
than December 31, 2000. These two nonattainment areas, while contiguous 
and share common planning elements, have separate timing requirements 
and are considered separate nonattainment areas.
    After these designations to nonattainment for the Pinehurst 
PM10 NAA, the IDEQ worked with the community of Pinehurst to 
develop a plan to bring the Pinehurst PM10 NAA into 
attainment. The IDEQ submitted a plan for the Pinehurst PM10 
NAA, both the original and expansion areas, to the EPA on April 14, 
1992, as a moderate PM10 State Implementation Plan (SIP) 
under section 189(a) of the CAA. The IDEQ's submitted plan addressed 
PM10 reductions through a suite of measures aimed at 
reducing wood smoke, primarily through a program to replace woodstoves 
with cleaner burning devices. The EPA conditionally approved the IDEQ's 
moderate PM10 SIP applicable to the City of Pinehurst on 
August 25, 1994 (59 FR 43745) and conditionally approved the revisions 
applicable to the Pinehurst PM10 Expansion area on May 26, 
1995 (60 FR 27891). Both plans were conditionally approved because 
these areas had failed to submit contingency measures. The IDEQ 
submitted a contingency plan covering both areas on July 13, 1995, 
which the EPA subsequently approved on October 2, 2014 (79 FR 59435). 
On August 23, 2001, the EPA published a finding that the two areas had 
attained the PM10 standard by their respective attainment 
dates (66 FR 44304).
    The IDEQ prepared a LMP for the Pinehurst PM10 NAA and 
provided notice and an opportunity for public comment on the proposed 
plan. On September 29, 2017, the IDEQ submitted the Pinehurst 
PM10 LMP to EPA for approval and has requested that the EPA 
redesignate the Pinehurst NAA to attainment for the PM10 
NAAQS.

III. Requirements for Redesignation

A. CAA Requirements for Redesignation of Nonattainment Area

    A nonattainment area can be redesignated to attainment after the 
area has measured air quality data showing the NAAQS has been attained 
and when certain planning requirements are met. Section 107(d)(3)(E) of 
the CAA, and the General Preamble to Title I provide the criteria for 
redesignation (57 FR 13498, April 16, 1992). These criteria are further 
clarified in a policy and guidance memorandum from John Calcagni, 
Director, Air Quality Management Division, EPA Office of Air Quality 
Planning and Standards dated September 4, 1992, entitled ``Procedures 
for Processing Requests to Redesignate Areas to Attainment'' (Calcagni 
memo). The criteria for redesignation are:
    1. The Administrator has determined that the area has attained the 
applicable NAAQS;
    2. The Administrator has fully approved the applicable SIP for the 
area under section 110(k) of the CAA;
    3. The state has met all requirements applicable to the area under 
section 110 and part D of the CAA;
    4. The Administrator has determined that the improvement in air 
quality is due to permanent and enforceable reductions in emissions; 
and
    5. The Administrator has fully approved a maintenance plan for the 
area as meeting the requirements of section 175A of the CAA.

B. The LMP Option for PM10 Nonattainment Areas

    On August 9, 2001, the EPA issued guidance on streamlined 
maintenance plan provisions for certain moderate PM10 
nonattainment areas seeking redesignation to attainment (Memo from 
Lydia Wegman, Director, Air Quality Standards and Strategies Division,

[[Page 21978]]

entitled ``Limited Maintenance Plan Option for Moderate PM10 
Nonattainment Areas'' (LMP Option memo)). The LMP Option memo contains 
a statistical demonstration that areas meeting certain air quality 
criteria will, with a high degree of probability, maintain the standard 
10 years into the future. Thus, the EPA has already provided the 
maintenance demonstration for areas meeting the criteria outlined in 
the LMP Option memo. It follows that future year emission inventories 
for these areas, and some of the standard analyses to determine 
transportation conformity with the SIP are no longer necessary.
    To qualify for the LMP Option, the area should have attained the 
PM10 NAAQS and, based upon the most recent five years of air 
quality data at all monitors in the area, the 24-hour design value 
should be at or below 98 [micro]g/m\3\. If an area cannot meet this 
test, it may still be able to qualify for the LMP Option if the average 
design value (ADV) for the site is less than the site-specific critical 
design value (CDV). In addition, the area should expect only limited 
growth in on-road motor vehicle PM10 emissions (including 
fugitive dust) and should have passed a motor vehicle regional 
emissions analysis test. The LMP Option memo also identifies core 
provisions that must be included in the LMP. These provisions include 
an attainment year emissions inventory, assurance of continued 
operation of an EPA-approved air quality monitoring network, and 
contingency provisions.

C. Conformity Under the LMP Option

    The transportation conformity rule and the general conformity rule 
(40 CFR parts 51 and 93) apply to nonattainment areas and maintenance 
areas covered by an approved maintenance plan. Under either conformity 
rule, an acceptable method of demonstrating that a Federal action 
conforms to the applicable SIP is to demonstrate that expected 
emissions from the planned action are consistent with the emissions 
budget for the area.
    While EPA's LMP Option does not exempt an area from the need to 
affirm conformity, it explains that the area may demonstrate conformity 
without conforming to an emissions budget. Under the LMP Option, 
emissions budgets are treated as essentially not constraining for the 
length of the maintenance period because it is unreasonable to expect 
that the qualifying areas would experience so much growth in that 
period that a violation of the PM10 NAAQS would result. For 
transportation conformity purposes, the EPA would conclude that 
emissions in these areas need not be capped for the maintenance period 
and therefore a regional emissions analysis would not be required. 
Similarly, Federal actions subject to the general conformity rule could 
be considered to satisfy the ``budget test'' specified in 40 CFR 
93.158(a)(5)(i)(A) for the same reasons that the budgets are 
essentially considered to be unlimited.

IV. Review of the Idaho Submittal Addressing the Requirements for 
Redesignation and LMPs

A. Has the Pinehurst PM10 NAA attained the applicable NAAQS?

    To demonstrate that an area has attained the PM10 NAAQS, 
the IDEQ must submit an analysis of ambient air quality data from an 
ambient air monitoring network representing peak PM10 
concentrations. The data should be quality-assured and stored in the 
EPA Air Quality System database. The EPA has reviewed air quality data 
for the area and has determined that the Pinehurst NAA attained the 
PM10 NAAQS \1\ by the applicable attainment dates of 
December 31, 1994 for the City of Pinehurst and December 31, 2000 for 
the Pinehurst PM10 Expansion area, and they continue to 
attain the PM10 NAAQS. EPA's analysis is described below.
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    \1\ Because the annual PM10 standard was revoked 
effective December 18, 2006, see 71 FR 61144 (October 17, 2006), 
this notice discusses only attainment of the 24-hour PM10 
standard.''
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    The 24-hour PM10 NAAQS is 150 [micro]g/m\3\. An area has 
attained this 24-hour standard when the average number of expected 
exceedances per year is less than or equal to one, when averaged over a 
three-year period (40 CFR 50.6). To make this determination, three 
consecutive years of complete ambient air quality data must be 
collected in accordance with Federal requirements (40 CFR part 58 
including appendices).
    A comprehensive air quality monitoring plan, meeting the 
requirements of 40 CFR part 58, was originally submitted by the IDEQ to 
the EPA on January 15, 1980, and approved by the EPA on July 28, 1982 
(40 CFR 52.670), and most recently submitted in June 2017, with 
approval by the EPA on November 8, 2017. The monitoring plan describes 
the Idaho monitoring network throughout the state, which includes the 
Pinehurst Idaho monitor (AQS ID 16-079-0017-81102-3). In the LMP 
submittal, the IDEQ states that the nonattainment designation was based 
on data collected at the Pinehurst monitoring site. With the exception 
of three high wind exceptional events, a review of data shows that 
PM10 3-year average expected exceedances recorded at this 
site have been less than or equal to the 24-hour PM10 NAAQS 
since 1994. In addition, the IDEQ states that the Pinehurst monitoring 
site is operated in compliance with the EPA monitoring guidelines set 
forth in 40 CFR part 58, Ambient Air Quality Surveillance.
    Data from the Pinehurst monitoring site has been quality assured by 
the IDEQ and submitted to the EPA's Air Quality System (AQS), 
accessible through the EPA's AirData website at https://www.epa.gov/outdoor-air-quality-data. To show attainment for the 24-hour 
PM10 NAAQS the three-year design value must be less than or 
equal to 1.0 expected number of exceedances, as established in Appendix 
K to 40 CFR part 50. The Pinehurst monitoring site recorded exceedances 
in 2013 and 2015 and the IDEQ flagged these exceedances as being the 
result of exceptional events where unusually high winds entrained dust. 
Under the EPA's Exceptional Events Rule, the Agency may exclude data 
from a regulatory determination related to an exceedance or violation 
of the NAAQS if the IDEQ adequately demonstrates that an exceptional 
event caused the exceedance or violation. 40 CFR 50.1 and 50.14. For 
the reasons set forth in the IDEQ's Pinehurst PM10 2013 High 
Wind Exceptional Event concurrence letter and analysis (March 2, 2017), 
the EPA excluded data showing an exceedance on September 15, 2013, in 
determining whether the Pinehurst NAA has attained the PM10 
NAAQS. The concurrence letter explains how the IDEQ met the Exceptional 
Event Rule criteria to demonstrate that the September 15, 2013 
exceedance qualifies as an exceptional event. Based on this 
demonstration, the IDEQ's submission demonstrates that the Pinehurst 
PM10 NAA's expected number of exceedances was 0.67 for 2013-
15, which is below the 1.0 upper limit. The EPA confirmed that the area 
continues to be less than or equal to the 1.0 expected number 
exceedances with the 2014-16 value being 0.7. The EPA therefore finds 
that the area was not violating the PM10 NAAQS.

B. Does the Pinehurst PM10 NAA have a fully approved SIP under section 
110(k) of the CAA?

    To qualify for redesignation, the SIP for an area must be fully 
approved under section 110(k) of the CAA, and must satisfy all 
requirements that apply to the area. As discussed in Section II.B. 
above, the IDEQ submitted a moderate PM10 SIP for the 
Pinehurst PM10 NAA on April 14, 1992. The EPA took final 
action to conditionally approve the IDEQ's moderate PM10 SIP 
on August

[[Page 21979]]

25, 1994 (59 FR 43745) for the City of Pinehurst and to conditionally 
approve the IDEQ's moderate PM10 SIP on May 26, 1995 (60 FR 
27891) for the Pinehurst PM10 Expansion area. These 
conditional approvals required submission of contingency measures. 
Accordingly, the IDEQ submitted the contingency plan applicable to the 
entire Pinehurst PM10 NAA as required by the conditional 
approvals on July 13, 1995. With the EPA's approval on October 2, 2014 
(79 FR 59435), the Pinehurst PM10 NAA satisfied all 
requirements that apply to the area and thus the area has a fully 
approved nonattainment area SIP under section 110(k) of the CAA.

C. Has the IDEQ met all applicable requirements under section 110 and 
Part D of the CAA?

    Section 107(d)(3)(E) of the CAA requires that a state containing an 
NAA meet all applicable requirements under section 110 and Part D of 
the CAA for the area to be redesignated to attainment. The EPA 
interprets this to mean that the IDEQ must meet all requirements that 
applied to the area prior to, and at the time of, the submission of a 
complete redesignation request. The following is a summary of how Idaho 
meets these requirements.
1. Clean Air Act Section 110 Requirements
    Section 110(a)(2) of the CAA contains general requirements for 
nonattainment plans. These requirements include, but are not limited 
to: Submittal of a SIP that has been adopted by the IDEQ after 
reasonable notice and public hearing; provisions for establishment and 
operation of appropriate apparatus, methods, systems and procedures 
necessary to monitor ambient air quality; implementation of a permit 
program; provisions for Part C--Prevention of Significant Deterioration 
(PSD) and Part D--New Source Review (NSR) permit programs; criteria for 
stationary source emission control measures, monitoring and reporting; 
provisions for modeling; and provisions for public and local agency 
participation. See the General Preamble for further explanation of 
these requirements (57 FR 13498, April 16, 1992). The EPA's approval of 
Idaho's SIP for attainment and maintenance of national standards can be 
found at 40 CFR 52.673. For purposes of redesignation of the Pinehurst 
PM10 NAA, the EPA has reviewed the IDEQ SIP and finds that 
the IDEQ has satisfied all applicable requirements under CAA section 
110(a)(2) for the PM10 NAAQS.
2. Part D Requirements
    Part D of the CAA contains general requirements applicable to all 
areas designated nonattainment. The general requirements are followed 
by a series of subparts specific to each pollutant. All PM10 
nonattainment areas must meet the general provisions of Subpart 1 and 
the specific PM10 provisions in Subpart 4, ``Additional 
Provisions for Particulate Matter Nonattainment Areas.'' The following 
paragraphs discuss these requirements as they apply to the Pinehurst 
PM10 NAA.
2a. Part D, Section 172(c)(2)--Reasonable Further Progress
    Section 172(c) contains general requirements for NAA plans. A 
thorough discussion of these requirements may be found in the General 
Preamble (57 FR 13538, April 16, 1992). CAA section 172(c)(2) requires 
nonattainment plans to provide for reasonable further progress (RFP). 
Section 171(1) of the CAA defines RFP as ``such annual incremental 
reductions in emissions of the relevant air pollutant as are required 
by this part (part D of title I) or may reasonably be required by the 
Administrator for the purpose of ensuring attainment of the applicable 
national ambient air quality standard by the applicable date.'' The 
requirements for reasonable further progress, identification of certain 
emissions increases and other measures needed for attainment were 
satisfied with the approved Pinehurst PM10 NAA SIP (59 FR 
43745 and 60 FR 27891). In its August 23, 2001 action (66 FR 44304), 
the EPA determined that the Pinehurst NAA attained the 24-hour 
PM10 NAAQS by the December 31, 1994 and December 31, 2000, 
attainment dates. Therefore, the EPA believes no further showing of RFP 
or quantitative milestones is necessary.
2b. Part D, Section 172(c)(3)--Emissions Inventory
    For redesignation, section 172(c)(3) of CAA requires a 
comprehensive, accurate, current inventory of actual emissions from all 
sources in the Pinehurst PM10 NAA. The IDEQ included an 
emissions inventory for the Pinehurst area for the year 2013 in the 
September 29, 2017 submittal. The IDEQ used 2013 as a base year for the 
emissions inventory, including data from the 2014 periodic emission 
inventory (PEI), as the IDEQ determined that it is representative of 
emissions during the five-year period associated with air quality data 
demonstrating attainment. The IDEQ has demonstrated that the 2013 base 
year emissions inventory is current, accurate, and comprehensive, and 
therefore meets the requirements of section 172(c)(3) of the CAA.
2c. Part D, Section 172(c)(5)--New Source Review (NSR)
    The CAA requires all nonattainment areas to meet several 
requirements regarding NSR. The IDEQ must have an approved major NSR 
program that meets the requirements of CAA section 172(c)(5). The Part 
D NSR rules for PM10 nonattainment areas in Idaho were 
approved by the EPA on July 23, 1993 (58 FR 39445) and amended on 
January 16, 2003 (68 FR 2217). Revisions to Idaho's NSR rules were most 
recently approved by the EPA on November 26, 2010 (75 FR 72719). Within 
the boundaries of the Pinehurst PM10 NAA, the requirements 
of the Part D NSR program will be replaced by the IDEQ's Prevention of 
Significant Deterioration (PSD) program requirements upon the effective 
date of redesignation. The currently approved NSR provisions meet the 
requirements of 172(c)(5) and therefore this condition for proposed 
redesignation is satisfied.
2d. Part D, Section 172(c)(7)--Compliance With CAA Section 110(a)(2): 
Air Quality Monitoring Requirements
    Once an area is redesignated, the IDEQ must continue to operate an 
appropriate air monitoring network in accordance with 40 CFR part 58 to 
verify the attainment status of the area. On January 15, 1980, the IDEQ 
submitted a comprehensive air quality monitoring plan, intended to meet 
the requirements of 40 CFR part 58. The EPA approved the plan on July 
28, 1982 (40 CFR 52.760). This monitoring plan has been updated, with 
the most recent submittal in June 2017, with approval by the EPA on 
November 8, 2017. The monitoring plan describes the PM10 
monitoring network throughout Idaho, including the Pinehurst monitoring 
site. The Pinehurst monitoring site is operated in compliance with the 
EPA monitoring guidelines set forth in 40 CFR part 58, Ambient Air 
Quality Surveillance. In addition, the Pinehurst PM10 NAA 
LMP submittal provides a commitment to continue operation of the 
PM10 monitoring network in accordance with 40 CFR part 58, 
and to annually verify continued attainment of the 24-hour 
PM10 NAAQS in Pinehurst through the Annual Ambient Air 
Monitoring Network Plan. Any changes to the monitoring site will be 
made via the Annual Ambient Air Monitoring Network Plan or formal 
communication. The currently approved monitoring plan

[[Page 21980]]

and associated program meet the requirements of 172(c)(7) and therefore 
this condition for proposed redesignation is satisfied.
2e. Part D, Section 172(c)(9)--Contingency Measures
    The CAA requires that contingency measures take effect if an area 
fails to meet RFP requirements or fails to attain the NAAQS by the 
applicable attainment date. On August 23, 2001, the EPA determined that 
the Pinehurst NAA attained the PM10 NAAQS by the applicable 
attainment dates of December 31, 1994 and December 31, 2000 (66 FR 
44304). Therefore, attainment planning contingency measures are no 
longer required under section 172(c)(9) of the CAA. However, 
maintenance plan contingency provisions are required for maintenance 
plans under section 175(a)(d). Please see section IV.I. for a 
description of Idaho's maintenance plan contingency provisions.
2f. Part D, Section 189(a), (c) and (e)--Additional Provisions for 
Particulate Matter Nonattainment Areas
    CAA sections 189(a), (c) and (e) apply to moderate PM10 
nonattainment areas. Any of these requirements which were applicable 
and due prior to the submission of the redesignation request must be 
fully approved into the SIP before redesignating the area to 
attainment. With respect to the Pinehurst NAA, these requirements 
include:
    (a) Provisions to assure that reasonably available control measures 
were implemented by December 31, 1994 and December 31, 2000 (section 
189(a)(1)(C));
    (b) Either a demonstration that the plan provided for attainment as 
expeditiously as practicable but not later than December 31, 1994 and 
December 31, 2000, or a demonstration that attainment by that date was 
impracticable (section 189(a)(1)(B));
    (c) Quantitative milestones which were achieved every three years 
and which demonstrate RFP toward attainment by December 31, 1994 and 
December 31, 2000 (section 189(c)(1)); and
    (d) Provisions to assure that the control requirements applicable 
to major stationary sources of PM10 also apply to major 
stationary sources of PM10 precursors except where the 
Administrator determined that such sources do not contribute 
significantly to PM10 levels which exceed the NAAQS in the 
area (section 189(e)).
    Provisions for reasonably available control measures, attainment 
demonstration, and RFP milestones were conditionally approved into the 
Pinehurst PM10 SIP on August 25, 1994 (59 FR 43745) and on 
May 26, 1995 (60 FR 27891). The EPA's approval of the July 13, 1995 
contingency plan on October 2, 2014 (79 FR 59435) fully approved these 
required elements The EPA approved changes to Idaho's major NSR rules 
on July 17, 2012 (77 FR 41916) and November 26, 2010 (75 FR 72719). The 
IDEQ's major nonattainment NSR rules and PSD rules include control 
requirements that apply to major stationary sources of PM10 
and PM10 precursors in nonattainment and attainment/
unclassifiable areas. Therefore, the EPA proposes that the requirements 
of 189(a)(c) and (e) for this proposed redesignation is satisfied.

D. Has the IDEQ demonstrated that the air quality improvement is due to 
permanent and enforceable reductions?

    Section 107(d)(3)(E)(iii) of the CAA provides that a NAA may not be 
redesignated unless the EPA determines that the improvement in air 
quality is due to permanent and enforceable reductions in emissions 
resulting from implementation of the SIP. Permanent and enforceable 
control measures in the Pinehurst PM10 SIP include controls 
primarily focused on residential wood combustion. The Pinehurst 
PM10 NAA LMP submittal describes its woodstove changeout 
program which resulted in 76 stove replacements by 1994 and an 
additional 87 replacements between 1996 and 2015. According to a recent 
survey in the community these 163 changeouts account for 60% of the 
uncertified devices in the area. Between 2015-17, 40 additional 
woodstoves have been changed out to cleaner burning devices under this 
program; 31 to EPA certified, 1 to propane, and 8 to natural gas. 
Additional permanent controls in the area include the weatherization of 
30 homes in the mid-1990s which provided for reductions in emissions by 
reducing home heating requirements which in turn reduce the need for 
additional fuel and the associated emissions.

E. Does the area have a fully approved maintenance plan pursuant to 
section 175A of the act?

    In this action, we are proposing to approve the LMP in accordance 
with the principles outlined in the LMP Option Memo. Upon final 
approval, the Pinehurst NAA will have a fully approved maintenance 
plan.

F. Has the IDEQ demonstrated that the Pinehurst NAA qualifies for the 
LMP Option?

    The LMP Option Memo outlines the requirements for an area to 
qualify for a LMP. First, the area should be attaining the NAAQS. On 
August 23, 2001, the EPA determined that the Pinehurst NAA attained the 
PM10 NAAQS by December 31, 1994 and December 31, 2000 (66 FR 
44304). The EPA has reviewed recent ambient air quality data for the 
24-hour PM10 NAAQS, and has determined that the Pinehurst 
NAA continues to attain the 24-hour PM10 NAAQS. Please see 
section IV.A. above for a detailed discussion.
    Second, the average design value (ADV) for the past five years of 
monitoring data must be at or below the critical design value (CDV). 
The CDV is a margin of safety value at which an area has been 
determined to have a one in ten probability of exceeding the NAAQS. The 
LMP Option Memo provides two methods to review monitoring data for the 
purpose of determining qualification for an LMP. The first method is a 
comparison of a site's ADV with the CDV of 98 [micro]g/m\3\ for the 24-
hour PM10 NAAQS. A second method that applies to the 24-hour 
PM10 NAAQS is the calculation of a site-specific CDV and a 
comparison of the site-specific CDV with the ADV for the past five 
years of monitoring data. The IDEQ's LMP submittal provides a 
comparison of five-year ADVs compared to the 24-hour and annual CDVs, 
as described in the first method for review of monitoring data to 
determine qualification for a LMP. The IDEQ's analysis demonstrates 
that the Pinehurst NAA has met the LMP design value criteria using the 
tabular look up method which showed the area to be meeting the CDV with 
a five-year design value of 83 [micro]g/m\3\. The EPA has reviewed the 
calculations and concurs with the IDEQ's findings that the area has a 
five-year design value of 83 [micro]g/m\3\ for both 2011-2015 and the 
most recently available five year DV of 2012-2016.\2\ Therefore, the 
EPA finds that the Pinehurst NAA meets the design value criteria 
outlined in the LMP Option Memo.
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    \2\ This LMP design value is dependent upon data being excluded 
from a high wind exceptional event also proposed for approval in 
this notice.
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    Third, the area must meet the motor vehicle regional emissions 
analysis test described in attachment B of the LMP Option Memo. Using 
the methodology outlined in the LMP Option Memo, the IDEQ has submitted 
an analysis of whether increased emissions from on-

[[Page 21981]]

road mobile sources would increase PM10 concentrations in 
the Pinehurst NAA to levels that would threaten the assumption of 
maintenance that underlies the LMP policy. Using this methodology, the 
IDEQ has determined that the Pinehurst NAA passes the motor vehicle 
regional emissions analysis test. The motor vehicle regional emissions 
analysis test results of 83.19 [micro]g/m\3\ and 83.36 [micro]g/m\3\ 
when adjusted for growth are below the 98 [micro]g/m\3\ annual standard 
and meet the margin of safety requirements. The EPA has reviewed the 
calculations in the IDEQ's Pinehurst NAA LMP submittal in Section 3.1 
and concurs with this conclusion.
    The LMP Option Memo requires all controls relied on to demonstrate 
attainment remain in place for a NAA to qualify for a LMP. The LMP 
developed by IDEQ will continue to implement the control measures 
relied upon to demonstrate attainment. Therefore, EPA proposes to find 
that the Pinehurst PM10 NAA meets the qualification criteria 
set forth in the LMP Option Memo, and therefore qualifies for a LMP.
    The LMP Option Memo also indicates that once a state submits a LMP 
and it is in effect, the IDEQ will be expected to determine, on an 
annual basis, that the LMP criteria are still being met. If the IDEQ 
determines that the LMP criteria are not being met, it should take 
action to reduce PM10 concentrations enough to requalify for 
the LMP. One possible approach the IDEQ could take is to implement 
contingency measures. Section IV.I. provides a description of 
contingency provisions submitted as part of the Pinehurst NAA LMP 
submittal. The EPA believes the contingency provisions submitted by the 
IDEQ meet the requirements of CAA section 175A as outlined in the LMP 
Option memo.

G. Does the IDEQ have an approved attainment emissions inventory which 
can be used to demonstrate attainment of the NAAQS?

    Pursuant to the LMP Option Memo, the IDEQ's approved attainment 
plan should include an emissions inventory which can be used to 
demonstrate attainment of the NAAQS. The inventory should represent 
emissions during the same five-year period associated with air quality 
data used to determine whether the area meets the applicability 
requirements of the LMP Option. The IDEQ should review its inventory 
every three years to ensure emissions growth is incorporated in the 
inventory if necessary.
    The IDEQ's Pinehurst PM10 NAA LMP submittal includes an 
emissions inventory, with a base year of 2013. After reviewing the 2013 
emissions inventory and determining that it is current, accurate and 
complete, as well as reviewing monitoring data, the EPA has determined 
that the 2013 emissions inventory is representative of the attainment 
year inventory because the NAAQS was not violated during 2013. In 
addition, the year 2013 is representative of the level of emissions 
during the time period used to calculate the average design value 
because 2013 is one of the years during the five-year period used to 
calculate the design value. The submittal meets EPA guidance, as 
described above, for purposes of an attainment emissions inventory.

H. Does the LMP include an assurance of continued operation of an 
appropriate EPA-approved air quality monitoring network, in accordance 
with 40 CFR part 58?

    A PM10 monitoring network was established in the 
Pinehurst area in 1985. The monitoring network was developed and has 
been maintained in accordance with Federal siting and design criteria 
in 40 CFR part 58, and in consultation with EPA Region 10. The EPA most 
recently approved the IDEQ's air monitoring plan on November 8, 2017. 
In the Pinehurst PM10 NAA LMP submittal, the IDEQ commits to 
continue to operate its monitoring network to meet the EPA requirements 
at 40 CFR part 58 and identify any issues or adjustments via the Annual 
Ambient Air Monitoring Network Plan or formal communication. The 
submittal contains an assurance of continued operation of the 
PM10 monitoring network. The submittal meets EPA LMP 
submission requirements with respect to maintenance of a monitoring 
network.

I. Does the plan meet the clean air act requirements for contingency 
provisions?

    The CAA section 175A states that a maintenance plan must include 
contingency provisions, as necessary, to ensure prompt correction of 
any violation of the NAAQS which may occur after redesignation of the 
area to attainment. As explained in the LMP Option Memo and the 
Calcagni Memo, these contingency provisions are considered to be an 
enforceable part of the federally-approved SIP. The maintenance plan 
should clearly identify the provisions to be adopted, a schedule and 
procedures for adoption and implementation, and a specific time limit 
for action by the IDEQ. The maintenance plan should identify the events 
that would ``trigger'' the adoption and implementation of a contingency 
provision, the contingency provision that would be adopted and 
implemented, and the schedule indicating the time frame by which the 
IDEQ would adopt and implement the provision. The LMP Option Memo and 
Calcagni Memo state that the EPA will determine the adequacy of a 
contingency plan on a case-by-case basis. At a minimum, it must require 
that the IDEQ will implement all measures contained in the CAA part D 
nonattainment plan for the area prior to redesignation.
    In the Pinehurst PM10 NAA LMP submittal, the IDEQ has 
included maintenance plan contingency provisions to ensure the area 
continues to meet the PM10 NAAQS. The submitted LMP includes 
the Annual Network Plan review process as the triggering mechanism for 
identifying if the Pinehurst area violates the PM10 NAAQS. 
If triggered the LMP identifies a list of specific control measures as 
listed in section 3.5.2 of their submittal to reduce emissions, 
including potential measures that would control emissions associated 
with residential wood combustion, controlling road-dust related 
emissions, and refuse burning for evaluation and a process for 
selection. Therefore, the EPA believes the contingency provisions 
submitted in the Pinehurst PM10 NAA LMP are adequate to meet 
CAA section 175A requirements.

J. How is conformity treated under a limited maintenance plan? \3\
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    \3\ See ``Limited Maintenance Plan Option for Moderate 
PM10 Nonattainment Areas'' memo from Director Lydia 
Wegman to Regional Offices dated August 9, 2001.
---------------------------------------------------------------------------

    The transportation conformity rule (40 CFR 51. 390 and 40 CFR 
93.100-129) and the general conformity rule (40 CFR 93.150-165) apply 
to nonattainment areas and maintenance areas operating under 
maintenance plans. Under either conformity rule one means of 
demonstrating conformity of Federal actions is to indicate that 
expected emissions from planned actions are consistent with the 
emissions budget for the area. Emissions budgets in LMP areas may be 
treated as essentially not constraining for the length of the 
maintenance period because it is unreasonable to expect that an area 
satisfying the LMP criteria will experience so much growth during that 
period of time such that a violation of the PM10 NAAQS would 
result. While this policy does not exempt an area from the need to 
affirm conformity, it does allow the area to demonstrate

[[Page 21982]]

conformity without undertaking certain requirements of these rules. For 
transportation conformity purposes, EPA would be concluding that 
emissions in these areas need not be capped for the maintenance period, 
and, therefore, a regional emissions analysis would not be required. 
Similarly, Federal actions subject to the general conformity rule could 
be considered to satisfy the ``budget test'' specified in Sec.  
93.158(a)(5)(i)(A) of the rule, for the same reasons that the budgets 
are essentially considered to be unlimited.
    The Pinehurst area is an isolated rural area \4\. Transportation 
conformity determinations in isolated rural nonattainment and 
maintenance areas are required only when a new non-exempt Federal 
Highway Administration (FHWA)/State Transportation Agency (STA) project 
needs funding or approval. Thus, in the event that a conformity 
analysis is required, the state agency responsible for conducting 
transportation conformity must document and ensure that:
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    \4\ As defined in 40 CFR 93.101, Isolated rural nonattainment 
and maintenance areas are areas that do not contain or are not part 
of any metropolitan planning area as designated under the 
transportation planning regulations. Isolated rural areas do not 
have Federally required metropolitan transportation plans (MTPs) or 
transportation improvement programs (TIPs) and do not have projects 
that are part of the emissions analysis of any metropolitan planning 
organization's (MPO's) MTP or TIP. Projects in such areas are 
instead included in statewide transportation improvement programs.
---------------------------------------------------------------------------

    (a) The interagency consultation procedures meet the applicable 
requirements of 40 CFR 93.105(c)(1)(vi);
    (b) Conformity is determined as specified in 40 CFR 93.109(g) for 
isolated rural areas.
    The minimum criteria by which the EPA determines whether a SIP is 
adequate for conformity purposes are specified at 40 CFR 93.118(e)(4). 
The EPA's analysis of how the LMP satisfies these criteria for 
transportation conformity is found in the docket. The EPA proposes to 
find adequate Idaho's LMP for Pinehurst for transportation conformity 
purposes.
    Upon final approval of the Pinehurst PM10 NAA LMP, the 
Pinehurst area will be exempt from performing a regional emissions 
analysis, but must meet project-level conformity analysis as well as 
the transportation conformity criteria located in 40 CFR 93.109(g) for 
isolated rural areas.

V. 2013 PM[bdi1][bdi0] High Wind Exceptional Event

    The CAA allows for the exclusion of air quality monitoring data 
from design value calculations when there are exceedances caused by 
events, such as wildfires or high wind events, that meet the criteria 
for an exceptional event identified in the EPA's implementing 
regulations, the Exceptional Events Rule at 40 CFR 50.1, 50.14 and 
51.930. In 2013 emissions from a high wind event entrained dust and 
impacted PM10 concentrations recorded at the Pinehurst 
monitor. For purposes of this Pinehurst PM10 redesignation 
and LMP, the IDEQ submitted an exceptional event demonstration to 
request exclusion of the data. The EPA evaluated the IDEQ's exceptional 
event demonstration for the flagged values of the 24-hour 
PM10 NAAQS for September 15, 2013, at the monitor in 
Pinehurst, Idaho, with respect to the requirements of the EPA's 
Exceptional Events Rule (40 CFR 50.14) and determined that IDEQ met the 
rule requirements. On March 2, 2017, the EPA concurred with the IDEQ's 
request to exclude event-influenced data for September 15, 2013. As 
such, the event-influenced data have been removed from the data set 
used for regulatory purposes and, for this proposed action, the EPA 
relies on the calculated values that exclude the event-influenced data. 
The EPA now proposes approval of the IDEQ's request to exclude data 
from September 15, 2013, in determining PM10 attainment as a 
high wind exceptional event. For further information, refer to the 
IDEQ's Exceptional Event demonstration package and the EPA's 
concurrence and analysis located in the docket for this regulatory 
action.

VI. West Silver Valley 2012 Annual PM[bdi2].[bdi5] Emission 
Inventory

A. 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 NAA. 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 NAA that contribute to the formation of a particular 
NAAQS pollutant. For the 2012 annual 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, if such a plan is required. The SIP submission should include 
documentation explaining how the state calculated the emissions data 
for the base year inventory. 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.

B. West Silver Valley PM2.5 Base Year Emissions Inventory

    The IDEQ developed a 2013 base year emissions inventory for the WSV 
annual PM2.5 NAA. The base year emissions inventory includes 
data from 2013 and 2014 and in large part was extracted from the 2014 
periodic emissions inventory (PEI) which is used to populate the EPA's 
National Emissions Inventory (NEI). The 2013 base year inventory is one 
of the three years used to designate the area as nonattainment. This 
base year inventory presents direct PM2.5 emissions 
(condensable and filterable) and emissions of all PM2.5 
precursors (NOX, VOCs, NH3, and SO2) 
to meet the emissions inventory requirements of CAA section 172(c). The 
IDEQ provided inventories from all sources in the WSV NAA, including 
nonpoint/area sources, point sources, nonroad sources, and onroad 
sources. The inventory is based on annual emissions in tons per year. 
The top source sectors of direct PM2.5 in the WSV are 
prescribed burns (88.91 tons/year (tpy)), residential wood combustion 
(52.61 tpy), onroad (17.25 tpy), unpaved roads (13.61 tpy), and nonroad 
(7.24 tpy) emissions.
    The largest source category of direct PM2.5 emissions in 
the WSV was from prescribed burning, accounting for 44.9% of direct 
PM2.5. These emissions came from primarily large and small 
scale permitted burners who burn forest waste mostly during the fall 
season. Emissions were estimated by extracting data, including fuel 
loading-moisture-acres burned-emissions factors, from prescribed burn 
databases maintained by the Idaho-Montana Air Shed Group and Idaho 
Department of Lands, and the Forest Practices Act Compliance database. 
The second largest source category is residential wood combustion 
(RWC). The emissions come from various residential devices designed to 
heat homes through burning wood whether in solid or pellet form.

[[Page 21983]]

Emissions from RWC, on an annual basis, account for about 26.6% of the 
base year direct PM2.5 emissions. These emissions were 
estimated using the EPA's Microsoft Access RWC tool v2.1 and estimates 
were adjusted with information from a local woodstove survey along with 
information from the ongoing woodstove changeout program in the area. 
The next three largest source categories, onroad emissions, unpaved 
roads emission, and nonroad emissions accounted for 30.9% of the direct 
PM2.5 in the base year emissions inventory. The onroad 
emissions source category includes emissions from motor vehicles and 
road dust from paved roads. The nonroad emissions source category 
includes winter and summer recreation vehicles and emissions generated 
from logging, construction and mining, and other minor nonroad sources. 
Onroad and nonroad emissions were calculated using MOVES2014.

C. EPA's Evaluation

    The EPA has reviewed the results, procedures, and methodologies for 
the WSV Annual PM2.5 NAA base year emissions inventory. The 
EPA has determined that the 2013 base year inventory for the WSV is 
based on the most current and accurate information available to the 
IDEQ at the time the inventories were being developed. The inventories 
comprehensively address all source categories in the WSV NAA, actual 
emissions are provided, and appropriate procedures were used to develop 
the inventories. We are proposing to approve the 2013 base year 
emissions inventory for the WSV NAA as meeting the requirements of CAA 
section 172(c)(3) and 40 CFR 51.1008(a)(1).

VII. Proposed Action

    The EPA is proposing to approve the Pinehurst PM10 NAA 
LMP submitted by the IDEQ for the Pinehurst NAA and concurrently 
redesignate the area to attainment for the PM10 NAAQS. The 
EPA has reviewed air quality data for the area and determined that the 
Pinehurst NAA attained the PM10 NAAQS by the required 
attainment date, and that air monitoring data continue to show 
attainment. The EPA is proposing to approve that the Pinehurst 
PM10 NAA LMP meets all of the requirements of an LMP and 
that the Pinehurst NAA meets all of the requirements of redesignation 
as described in this action.
    The EPA is also taking action to propose approval of the September 
15, 2013, high wind exceptional event that impacted PM10 
values in the area.
    The EPA is also taking action to propose approval of the WSV Annual 
PM2.5 base year Emissions Inventory as meeting CAA 172(c)(3) 
requirements.

VIII. 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 it does not involve technical standards; 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 and will not impose substantial 
direct costs on tribal governments or preempt tribal law as specified 
by Executive Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects

40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Particulate matter, Reporting 
and recordkeeping requirements.

40 CFR Part 81

    Environmental protection, Air pollution control, National parks, 
Wilderness areas.

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

    Dated: April 30, 2018.
Chris Hladick,
Regional Administrator, Region 10.
[FR Doc. 2018-09992 Filed 5-10-18; 8:45 am]
 BILLING CODE 6560-50-P


