Document ID: EPA-R08-OAR-2017-0656-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Wyoming; Sheridan PM10 Nonattainment Area Limited Maintenance Plan and Redesignation Request
Posted Date: 2018-01-29T05:00Z

[Federal Register Volume 83, Number 19 (Monday, January 29, 2018)]
[Proposed Rules]
[Pages 4015-4022]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-01493]

=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2017-0656; FRL-9972-67-Region 8]

Approval and Promulgation of Air Quality Implementation Plans; 
State of Wyoming; Sheridan PM10 Nonattainment Area Limited Maintenance 
Plan and Redesignation Request

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
fully approve the Limited Maintenance Plan (LMP), submitted by the 
State of Wyoming to the EPA on June 2, 2017, for the Sheridan moderate 
PM10 nonattainment area (Sheridan NAA) and concurrently 
redesignate the Sheridan NAA to attainment of the National Ambient Air 
Quality Standard (NAAQS) for particulate matter with an aerodynamic 
diameter less than or equal to a nominal 10 micrometers 
(PM10). In order to approve the LMP and redesignation, the 
EPA is proposing to determine that the Sheridan NAA has attained the 
1987 24-hour PM10 NAAQS of 150 [micro]g/m\3\. This 
determination is based upon monitored air quality data for the 
PM10 NAAQS during the years 2014-2016. Additionally, the EPA 
is proposing to approve the Sheridan LMP as meeting the appropriate 
transportation conformity requirements found in 40 CFR 93, subpart A.

DATES: Written comments must be received on or before February 28, 
2018.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2017-0656 at http://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from www.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 the 
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: James Hou, Air Program, U.S. 
Environmental Protection Agency (EPA), Region 8, Mail Code 8P-AR, 1595 
Wynkoop Street, Denver, Colorado 80202-1129, (303) 312-6210, 
[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

What should I consider as I prepare my comments for EPA?

    1. Submitting Confidential Business Information (CBI). Do not 
submit CBI to the EPA through http://www.regulations.gov or email. 
Clearly mark the part or all of the information that you claim to be 
CBI. For CBI information on a disk or CD ROM that you mail to the EPA, 
mark the outside of the disk or CD ROM as CBI and then identify 
electronically within the disk or CD ROM the specific information that 
is

[[Page 4016]]

claimed as CBI. In addition to one complete version of the comment that 
includes information claimed as CBI, a copy of the comment that does 
not contain the information claimed as CBI must be submitted for 
inclusion in the public docket. Information so marked will not be 
disclosed except in accordance with procedures set forth in 40 CFR part 
2.
    2. Tips for preparing your comments. When submitting comments, 
remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register volume, 
date, and page number);
     Follow directions and organize your comments;
     Explain why you agree or disagree;
     Suggest alternatives and substitute language for your 
requested changes;
     Describe any assumptions and provide any technical 
information and/or data that you used;
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced;
     Provide specific examples to illustrate your concerns, and 
suggest alternatives;
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats; and,
     Make sure to submit your comments by the comment period 
deadline identified.

II. Background of the Sheridan PM10 Nonattainment Area 
(Sheridan NAA)

A. Description of the Sheridan Nonattainment Area

    The Sheridan NAA encompasses the City of Sheridan, Wyoming, and was 
designated nonattainment for the 1987 24-hour PM10 NAAQS and 
classified as moderate under sections 107(d)(4)(B), following enactment 
of the Clean Air Act (CAA) Amendments of 1990. See 56 FR 56694 
(November 6, 1991). States containing initial moderate PM10 
nonattainment areas were required to submit, by November 15, 1991, a 
moderate nonattainment area State Implementation Plan (SIP) that, among 
other requirements, implemented Reasonably Available Control Measures 
(RACM) by December 10, 1993, and demonstrated whether it was 
practicable to attain the PM10 NAAQS by December 31, 1994. 
See generally 57 FR 13498 (April 16, 1992); see also 57 FR 18070 (April 
28, 1992).
    The State of Wyoming submitted an initial PM10 SIP to 
the EPA on August 28, 1989, and subsequently submitted eight additional 
submittals between 1989 and 1991. The State of Wyoming's SIP for the 
Sheridan moderate nonattainment area included, among other things: A 
comprehensive emissions inventory; RACM; a demonstration that 
attainment of the PM10 NAAQS would be achieved in Sheridan 
by December 31, 1994; Reasonable Further Progress (RFP) requirements; 
and control measures that satisfy the contingency measures requirement 
of section 172(c)(9) of the CAA.

III. Requirements for Redesignation

A. CAA Requirements for Redesignation of Nonattainment Areas

    Nonattainment areas can be redesignated to attainment after the 
area has measured air quality data showing it has attained the NAAQS 
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. See 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, ``Procedures 
for Processing Requests to Redesignate Areas to Attainment.'' \1\ The 
criteria for redesignation are:
---------------------------------------------------------------------------

    \1\ The ``Procedures for Processing Requests to Redesignate 
Areas to Attainment'' (Calcagni memo) outlines the criteria for 
redesignation. The Calcagni memo can be found at https://www.epa.gov/sites/production/files/2016-03/documents/calcagni_memo_-_procedures_for_processing_requests_to_redesignate_areas_to_attainment_090492.pdf.
---------------------------------------------------------------------------

    (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 containing the area 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, 
entitled ``Limited Maintenance Plan Option for Moderate PM10 
Nonattainment Areas,'' (hereafter the LMP Option memo)).\2\ 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 
1987 24-hour PM10 NAAQS, the average annual PM10 
design value for the area, based upon the most recent five years of air 
quality data at all monitors in the area, should be at or below 40 
[micro]g/m\3\, and the 24-hour design value should be at or below 98 
[micro]g/m\3\. The annual PM10 standard was effectively 
revoked on December 18, 2006 (71 FR 61143), and as such will not be 
discussed as a requirement for qualifying for the LMP option. 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 (40 CFR parts 51 and 93) 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 the EPA's LMP Option does not exempt an area from the need to 
affirm conformity, it explains that the area may demonstrate conformity 
without submitting 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

[[Page 4017]]

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 not limited.

IV. Review of the Wyoming State Submittal Addressing the Requirements 
for Redesignation and Limited Maintenance Plans

A. Has the Sheridan NAA attained the applicable NAAQS?

    States must demonstrate that an area has attained the 24-hour 
PM10 NAAQS through analysis of ambient air quality data from 
an ambient air monitoring network representing peak PM10 
concentrations. The data should be stored in the EPA Air Quality System 
(AQS) database. The EPA is proposing to determine that the Sheridan NAA 
has attained the PM10 NAAQS based on monitoring data from 
calendar years 2014-2016. The 24-hour standard is attained when the 
expected number of days with levels above 150 [micro]g/m\3\ (averaged 
over a three-year period) is less than or equal to one. 40 CFR 50.6(a). 
Three consecutive years of air quality data are generally necessary to 
show attainment of the 24-hour and annual standards for 
PM10. See 40 CFR part 50, appendix K. A complete year of air 
quality data, as referred to in 40 CFR part 50, appendix K, is 
comprised of all four calendar quarters with each quarter containing 
data from at least 75 percent of the scheduled sampling days.
    The Sheridan NAA has two State and Local Air Monitoring Stations 
(SLAMS) monitors operated by the Wyoming Department of Environmental 
Quality (WDEQ). Table 1 summarizes the PM10 data collected 
from 2012-2016. The EPA deems the data collected from these monitors 
valid, and the data has been submitted by the WDEQ to be included in 
AQS.

          Table 1--Summary of Maximum 24-Hour PM10 Concentrations [micro]g/m\3\ for Sheridan 2012-2016
               [Based on data from Sheridan Police Station, AQS Identification Number 56-033-0002]
----------------------------------------------------------------------------------------------------------------
                                          Maximum       2nd Maximum
                                       concentration   concentration     Number of
                Year                    ([micro]g/      ([micro]g/      exceedances         Monitoring site
                                           m\3\)           m\3\)
----------------------------------------------------------------------------------------------------------------
2012................................              75              73               0  Police Station.
2013................................              57              52               0  Police Station.
2014................................              47              45               0  Police Station.
2015................................              73              73               0  Police Station.
2016................................              54              48               0  Police Station.
----------------------------------------------------------------------------------------------------------------

    The PM10 concentrations reported at the Sheridan 
monitoring sites showed no measured exceedances of the 24-hour 
PM10 NAAQS, and as such, the EPA proposes to determine that 
the Sheridan Moderate NAA has attained the standard for the 24-hour 
PM10 NAAQS.

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

    In order to qualify for redesignation, the SIP for the area must be 
fully approved under CAA section 110(k), and must satisfy all 
requirements that apply to the area. Section 107(d)(4)(B) of the CAA 
contains requirements and milestones for all initial moderate 
nonattainment area SIPs including: (1) Provisions to assure that RACM 
(including such reductions in emissions from existing sources in the 
area as may be obtained through the adoption, at a minimum, of 
Reasonably Available Control Technology--RACT) shall be implemented no 
later than December 10, 1993; (2) A demonstration (including air 
quality modeling) that the plan will provide for attainment as 
expeditiously as practicable by no later than December 31, 1994, or, 
where the state is seeking an extension of the attainment date under 
section 188(e), a demonstration that attainment by December 31, 1994, 
is impracticable and that the plan provides for attainment by the most 
expeditious alternative date practicable (CAA sections 189(a)(1)(A)); 
(3) Quantitative milestones which are to be achieved every three years 
and which demonstrate RFP toward attainment by December 31, 1994, (CAA 
sections 172(c)(2) and 189(c)); and (4) Contingency measures to be 
implemented if the area fails to make RFP or attain by its attainment 
deadline. These contingency measures are to take effect without further 
action by the State or the EPA. (CAA section 172(c)(9)).
    As stated above, on June 23, 1994, the EPA approved Sheridan's 
moderate area plan including RACM, an attainment demonstration, 
emissions inventory, quantitative milestones, and control and 
contingency measure requirements. As such, the area has a fully 
approved nonattainment area SIP under section 110(k) of the CAA.

C. Has the State 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 a 
nonattainment area must meet all applicable requirements under section 
110 and Part D of the CAA for an area to be redesignated to attainment. 
The EPA interprets this to mean that the state 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 Wyoming meets these requirements.
(1) CAA 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 state 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

[[Page 4018]]

participation. See the General Preamble for further explanation of 
these requirements. 57 FR 13498 (April 16, 1992).
    For purposes of redesignation, the EPA's review of the Wyoming SIP 
shows that the State has satisfied all requirements under section 
110(a)(2) of the CAA. Further, in 40 CFR 52.2622, the EPA has approved 
Wyoming's plan for the attainment and maintenance of the national 
standards under section 110.
(2) Part D Requirements
    Part D 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 Sheridan 
NAA.
(3) Subpart 1, Section 172(c)
    Subpart 1, section 172(c) contains general requirements for 
nonattainment area plans. A thorough discussion of these requirements 
may be found in the General Preamble. See 57 FR 13538 (April 16, 1992). 
CAA section 172(c)(2) requires nonattainment plans to provide for 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.'' Wyoming 
submitted their first quantitative milestone report on March 29, 1995. 
Since the EPA is proposing to determine that the Sheridan NAA is in 
attainment of the PM10 NAAQS, we believe that no further 
showing of RFP or quantitative milestones is necessary.
(4) Section 172(c)(3)--Emissions Inventory Section
    Section 172(c)(3) of the CAA requires a comprehensive, accurate, 
current inventory of actual emissions from all sources in the Sheridan 
PM10 nonattainment area. Wyoming included an emissions 
inventory for the calendar year 2014 with its DATE? submittal of the 
LMP for the Sheridan NAA. Based on the inventory preparation plan for 
the PM10 2014 base year emissions inventory, which includes 
windblown dust sources, the 2014 base year emissions inventory is 
current, accurate and comprehensive; and therefore, meets the 
requirements of Section 172(c)(3) of the CAA.
(5) Section 172(c)(5)--NSR
    The 1990 CAA Amendments contained revisions to the NSR program 
requirements for the construction and operation of new and modified 
major stationary sources located in nonattainment areas. The CAA 
requires states to amend their SIPS to reflect these revisions, but 
does not require submittal of this element along with the other SIP 
elements. The CAA established June 30, 1992, as the submittal date for 
the revised NSR programs (Section 189 of the CAA). In lieu of 
instituting NSR regulations for construction in the Sheridan NAA, the 
State of Wyoming chose to institute a construction ban on major sources 
for the Sheridan NAA, which was deemed to have satisfied the NSR 
requirements, and was approved into the Wyoming SIP on November 29, 
1994 (59 FR 60931).
(6) Section 172(c)(7)--Compliance With CAA Section 110(a)(2): Air 
Quality Monitoring Requirements
    Once an area is redesignated, the state must continue to operate an 
appropriate air monitoring network in accord with 40 CFR part 58 to 
verify attainment status of the area. The State of Wyoming and the City 
of Sheridan operate two PM10 SLAMS in the Sheridan NAA. Both 
monitoring sites meet EPA SLAMS network design and siting requirements 
set forth at 40 CFR part 58, appendices D and E. The Police Station 
monitor has been in continuous operation since 1985, while the second 
monitoring station has been moved several times since 1998, but is 
currently sited at the Meadowlark Elementary School. In Section 6.6 of 
the LMP that we are proposing to approve, the State commits to 
continued operation of the monitoring network.
(7) Section 172(c)(9)--Contingency Measures
    The CAA requires that contingency measures take effect if the area 
fails to meet RFP requirements or fails to attain the NAAQS by the 
applicable attainment date. Since the Sheridan NAA attained the 1987 
24-hour PM10 NAAQS by the applicable attainment date of 
December 31, 1994, contingency measures are no longer required under 
Section 172(c)(9) of the CAA. However, contingency provisions are 
required for maintenance plans under Section 175(a)(d). We describe the 
contingency provisions Wyoming provided in the Sheridan LMP below.
(8) Part D Subpart 4
    Part D Subpart 4, Section 189(a), (c) and (e) requirements apply to 
any moderate nonattainment area before the area can be redesignated to 
attainment. The requirements which were applicable prior to the 
submission of the request to redesignate the area must be fully 
approved into the SIP before redesignating the area to attainment. 
These requirements include: (a) Provisions to assure that RACM was 
implemented by December 10, 1993; (b) Either a demonstration that the 
plan provided for attainment as expeditiously as practicable but not 
later than December 31, 1994, or a demonstration that attainment by 
that date was impracticable; (c) Quantitative milestones which were 
achieved every three years and which demonstrate RFP toward attainment 
by December 31, 1994; 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. These provisions were fully approved into the SIP 
upon the EPA's approval of the PM10 moderate area plan for 
the Sheridan NAA on June 23, 1994 (See 59 FR 32370), and the EPA is 
proposing to approve the attainment demonstration, based on the 
maintenance demonstration submitted with the LMP, in this action.

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

    The state must be able to reasonably attribute the improvement in 
air quality to permanent and enforceable emission reductions. In making 
this showing, the state must demonstrate that air quality improvements 
are the result of actual enforceable emission reductions. This showing 
should consider emission rates, production capacities, and other 
related information. The analysis should assume that sources are 
operating at permitted levels (or historic peak levels) unless evidence 
is presented that such an assumption is unrealistic. Permanent and 
enforceable control measures in the Sheridan NAA SIP include RACM. 
Emission sources in the Sheridan NAA have been implementing RACM for at 
least 10 years. In the EPA's approval of the Sheridan attainment plan 
on June 23, 1994, the EPA acknowledged that the primary source category

[[Page 4019]]

contributing to the PM10 nonattainment problem in Sheridan 
was fugitive road dust. The State demonstrated that, by applying the 
control measure, the ''Sanding Winter Maintenance Plan'' (SWMP), to 
designated streets during the Winter season, Sheridan would effectively 
control fugitive road dust; and thus, be in attainment by December 31, 
1994. The State has noted that there have been updates to the SWMP, 
that are congruent with the original SWMP. However, in the intervening 
years since the approval of the Sheridan NAA attainment plan, many of 
the roads which were unpaved, have now been paved, allowing for plowing 
of the roads as opposed to frequent sanding. In the instances where 
sanding is still applied, it is applied consistent with the 1994 SWMP, 
as noted in section 3.3 of the Sheridan LMP.
    Areas that qualify for the LMP will meet the NAAQS, even under 
worst case meteorological conditions. Under the LMP option, the 
maintenance demonstration is presumed to be satisfied if an area meets 
the qualifying criteria. Thus, by qualifying for the LMP, Wyoming has 
demonstrated that the air quality improvements in the Sheridan area are 
the result of permanent emission reductions and not a result of either 
economic trends or meteorology. A description of the LMP qualifying 
criteria and how the Sheridan area meets these criteria is provided in 
the following section.

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

    In this action, we are proposing to approve the Limited Maintenance 
Plan in accordance with the principles outlined in the LMP Option.

F. Has the state demonstrated that the Sheridan NAA qualifies for the 
LMP Option?

    The LMP Option memo outlines the requirements for an area to 
qualify for the LMP Option. First, the area should be attaining the 
NAAQS. As stated above in Section IV.A., the EPA has determined that 
the Sheridan NAA is attaining the PM10 NAAQS, based upon 
2014-2016 data, and has had no exceedances between the years 2008-2016.
    Second, the average design value (ADV) for the past five years of 
monitoring data (2012-2016) must be at or below the critical design 
value (CDV). The CDV is a margin of safety value and is the value at 
which an area has been determined to have a 1 in 10 probability of 
exceeding the NAAQS. The LMP Option memo provides two methods for 
review of monitoring data for the purpose of qualifying for the LMP 
option. 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. 
Table 2 outlines the design values for the years 2012-2016, and 
presents the ADV.

              Table 2--Summary of 24-Hour PM10 Design Values ([micro]g/m\3\) for Sheridan 2012-2016
[Based on data from Sheridan Police Station and Meadowlark Elementary, AQS Identification Number 56-033-0002 and
                                                  56-033-1003]
----------------------------------------------------------------------------------------------------------------
                                                Design value
              Design value years                 ([micro]g/                     Monitoring site
                                                    m\3\)
----------------------------------------------------------------------------------------------------------------
2012-2014....................................              60  Police Station.
2013-2015....................................              57  Police Station.
2014-2016....................................              72  Police Station.
2012-2014....................................             (*)  Meadowlark Elementary.
2013-2015....................................              72  Meadowlark Elementary.
2014-2016....................................              72  Meadowlark Elementary.
----------------------------------------------------------------------------------------------------------------
Average DV based on highest DVs..............................  68 [micro]g/m\3\.
----------------------------------------------------------------------------------------------------------------
* The Meadowlark School monitor was installed on July 2012, and therefore missing the first two quarters in
  2012. The 2012-2014 DV from the Police Station monitor was used to calculate the ADV for the NAA.

    The ADV for the 24-hour PM10 NAAQS for Sheridan, based 
on data from the collocated SLAMS monitors for the years 2012-2016, is 
68 [micro]g/m\3\. This value falls below the presumptive 24-hour CDV of 
98 [micro]g/m\3\. Therefore, Sheridan meets the design value criteria 
outlined in the LMP Option memo. For the 2012-2016 ADV calculations for 
PM10 in Sheridan, please see the supporting documents in the 
docket.\3\
---------------------------------------------------------------------------

    \3\ See memo to file dated November 17, 2017 titled 
``PM10 24-hour Design Concentration for Sheridan 
Wyoming.''
---------------------------------------------------------------------------

    Third, the area must meet the motor vehicle regional emissions 
analysis test in attachment B of the LMP Option memo. Using the 
methodology outlined in the memo, based on monitoring data for the 
period 2014-2016, the EPA has determined that the Sheridan NAA passes 
the motor vehicle regional emissions analysis test. For the 
calculations used to determine that Sheridan has passed the motor 
vehicle regional analysis test, see the supporting documents in the 
docket.\4\
---------------------------------------------------------------------------

    \4\ See memo to file dated December 4, 2017, title ``Sheridan 
Motor Vehicle Regional Emissions Analysis.''
---------------------------------------------------------------------------

    The monitoring data for the period 2014-2016 shows that Sheridan 
has attained the NAAQS for PM10, the 24-hour ADV for 
Sheridan is less than the 24-hour PM10 CDV. Finally, the 
area has met the regional vehicle emissions analysis test. Thus, the 
Sheridan NAA qualifies for the LMP Option described in the LMP Option 
memo. The LMP Option memo also indicates that once a state selects the 
LMP Option and it is in effect, the state will be expected to 
determine, on an annual basis, that the LMP criteria are still being 
met. If the state 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 state could take is 
to implement contingency measures. Please see Section 6.3. for a 
description of contingency provisions submitted as part of the State's 
submittal.

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

    The state's approved attainment plan should include an emissions 
inventory (attainment 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

[[Page 4020]]

requirements of the LMP Option. The state should review its inventory 
every three years to ensure emissions growth is incorporated in the 
attainment inventory if necessary. In this instance, Wyoming completed 
an attainment year inventory for the attainment year 2014. The EPA has 
reviewed the 2014 emissions inventory and determined that it is 
current, accurate and complete. The EPA has also reviewed monitoring 
data for the years 2012-2016, and determined that the 2014 emissions 
inventory is representative of the attainment year inventory since the 
NAAQS was not violated during 2014. In addition, the emissions 
inventory submitted with the LMP for the calendar year 2014 is 
representative of the level of emissions during the time period used to 
calculate the average design value since 2014 is included in the five-
year period used to calculate the design value (2012-2016). As stated 
above in Section IV.C.4., the 2014 emissions inventory meets the 
requirements of Section 172(c)(3) of the CAA, and the requirements for 
emissions inventory in Table 3.1 of the EPA document entitled 
PM10 Emission Inventory Requirements, Final Report.

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 
Sheridan NAA in 1984. Since that time, the Police Station monitor has 
been in continuous operation, while the neighborhood monitor has been 
moved several times since 1998. The neighborhood monitor is currently 
sited at the Meadowlark Elementary School. The monitoring network was 
developed and has been maintained in accordance with federal siting and 
design criteria in 40 CFR part 58, Appendices D and E and in 
consultation with EPA Region 8. Currently, there are two 
PM10/PM2.5 SLAMS/National Air Monitoring Stations 
(NAMS) monitors in the Sheridan NAA. In Section 6.6 of the Sheridan 
LMP, Wyoming states that it will continue to operate its monitoring 
network to meet EPA requirements.

I. Does the plan meet the CAA requirements for contingency provisions 
for maintenance plans?

    Section 175A of the CAA states that a maintenance plan must include 
contingency provisions, as necessary, to promptly correct any violation 
of the NAAQS which may occur after redesignation of the area to 
attainment. As explained in the LMP Option memo, these contingency 
measures do not have to be fully adopted at the time of redesignation. 
As noted above, CAA section 175A requirements are distinct from CAA 
section 172(c)(9) contingency measures. Section 6.3 of the Sheridan 
Limited Maintenance Plan describes a process and timeline to identify 
and evaluate appropriate contingency measures in the event of a quality 
assured violation of the PM10 NAAQS. Upon notification of a 
PM10 exceedance, the AQD and local government staff in the 
Sheridan area will develop appropriate contingency measure(s) intended 
to prevent or correct a violation of the PM10 standard. 
Information about historical exceedances of the standard, the 
meteorological conditions related to the recent exceedance(s), and the 
most recent estimates of growth and emissions will be reviewed. The 
possibility that an exceptional event occurred will also be evaluated. 
The AQD will notify the EPA Region 8 within 45 days of any exceedance. 
Usually, upon notification to the Region, the AQD will indicate whether 
it believes that the event could be exceptional. If the event is 
considered eligible for data exclusion by the AQD, the AQD then 
provides official notification per the CFR (40 CFR 50.14) by flagging 
the affected data and providing a description with the quarterly data 
uploaded to AQS (90 days after the end of the quarter in which the 
event took place). Additionally, under the 2016 revisions to the 
Treatment of Data Influenced by Exceptional Events Rule (81 FR 68216), 
the AQD would confer with EPA Region 8 regarding whether the flagged 
event would meet the criteria of a regulatory decision, and if so, a 
determination would be made on whether to move forward with producing a 
demonstration. This process will be completed within six months of the 
exceedance notification. If a violation of the PM10 NAAQS 
has occurred, a public hearing process at the State and local level 
will begin. Contingency measures will be adopted and fully implemented 
within one year of a PM10 NAAQS violation. Any State-
enforceable measures will become part of the next revised maintenance 
plan, submitted to the EPA for approval.
    Potential contingency provisions identified in the Sheridan LMP 
include the following:
     Re-implementing the voluntary wood burning curtailment 
program.
     Re-implementing the wood burning public information 
campaign.
     Mandatory wood burning curtailment.
     Bans on all wood burning.
     Implementing nonattainment new source review regulations 
for the City of Sheridan.
     Re-establishing the construction ban on major stationary 
sources that had been removed from Wyoming's State Implementation Plan.
     Paving the remaining unpaved roads within the City of 
Sheridan.
     Other restrictions/regulations/action plans involving 
stationary sources based on the consideration of cost-effectiveness, 
PM10 emission reduction potential, economic and social 
considerations, or other factors that the State deems appropriate.
     Coordination with the Wyoming Department of 
Transportation/local transit agency regarding roadwork and 
transportation control measures.
    The current and proposed contingency provisions in Sheridan's LMP 
meet the requirements for contingency provisions as outlined in the LMP 
Option memo.

J. Has the state met transportation conformity requirements?

(1) Transportation Conformity
    Transportation conformity is required by section 176(c) of the CAA. 
Conformity to a SIP means that transportation activities will not 
produce new air quality violations, worsen existing violations, or 
delay timely attainment of the NAAQS (CAA section 176(c)(1)(B)). The 
EPA's conformity rule at 40 CFR part 93, subpart A requires that 
transportation plans, programs and projects conform to SIPs and 
establishes the criteria and procedures for determining whether or not 
they conform. To effectuate its purpose, the conformity rule requires a 
demonstration that emissions from the Regional Transportation Plan, if 
applicable, and the Transportation Improvement Program are consistent 
with the motor vehicle emission budget (MVEB) contained in the control 
strategy SIP revision or maintenance plan (40 CFR 93.101, 93.118, and 
93.124). The EPA notes that a MVEB is typically defined as the level of 
mobile source emissions of a pollutant relied upon in the attainment or 
maintenance demonstration to attain or maintain compliance with the 
NAAQS in the nonattainment or maintenance area.\5\ MVEBs are, however, 
treated differently with respect to LMP areas.
---------------------------------------------------------------------------

    \5\ Further information concerning the EPA's interpretations 
regarding MVEBs can be found in the preamble to the EPA's November 
24, 1993, transportation conformity rule (see 58 FR 62193-62196).
---------------------------------------------------------------------------

    We note that under our LMP Option memorandum, MVEBs are not 
required

[[Page 4021]]

to be identified in the maintenance plan. While the EPA's LMP Option 
memo does not exempt an area from the need to affirm conformity, it 
explains that the area may demonstrate transportation conformity 
without identifying and submitting a MVEB. The basis for this provision 
in the LMP Option memorandum is that it is unreasonable to expect that 
an LMP area will experience so much growth during the maintenance 
period that a violation of the PM10 NAAQS would result. 
Therefore, for transportation conformity purposes, the EPA has 
concluded that mobile source emissions in LMP areas need not be capped, 
with respect to a MVEB, for the maintenance period and a regional 
emissions analysis (40 CFR 93.118), for transportation conformity 
purposes, is also not required.
    However, since LMP areas are still maintenance areas, certain 
aspects of the EPA's transportation conformity rule will continue to be 
required for transportation projects located within the Sheridan 
PM10 maintenance area. Specifically, for conformity 
determinations, projects will have to demonstrate that they are 
fiscally constrained (40 CFR 93.108) and meet the criteria for 
consultation and timely implementation (as applicable) of 
Transportation Control Measures (40 CFR 93.112 and 40 CFR 93.113, 
respectively). In addition, projects located within the Sheridan 
PM10 LMP area will be required to be evaluated for potential 
PM10 hot-spot issues in order to satisfy the ``project 
level'' conformity determination requirements. As appropriate, a 
project may then need to address the applicable criteria for a 
PM10 hot-spot analysis as provided in 40 CFR 93.116 and 40 
CFR 93.123.
    Finally, our proposed approval of the Sheridan PM10 LMP 
affects future PM10 project-level transportation conformity 
determinations as prepared by the Wyoming Department of Transportation 
in conjunction with the Federal Highway Administration and the Federal 
Transit Administration. See 40 CFR 93.100. As such, the EPA is 
proposing to approve the Sheridan LMP as meeting the appropriate 
transportation conformity requirements found in 40 CFR 93, subpart A.
(2) General Conformity
    Federal actions, other than transportation conformity, that meet 
specific criteria need to be evaluated with respect to the requirements 
of Wyoming's general conformity rule.\6\ Wyoming's general conformity 
rule requirements are designed to ensure that emissions from a federal 
action will not cause or contribute to new violations of the NAAQS, 
exacerbate current violations, or delay timely attainment. However, as 
noted in our LMP Option memorandum, and similar to the above discussed 
transportation conformity provisions, federal actions subject to 
Wyoming's general conformity rule would be considered to satisfy the 
``budget test,'' as specified in WAQSR Chapter 8, Section 3(c)(vii)(C) 
of the rule. As discussed above, the basis for this provision in the 
LMP Option memorandum is that it is unreasonable to expect that an LMP 
area will experience so much growth during the maintenance period that 
a violation of the PM10 NAAQS would result. Therefore, for 
purposes of general conformity, a general conformity PM10 
emissions budget does not need to be identified in the maintenance 
plan, nor submitted, and the emissions from federal agency actions are 
essentially considered to not be limited.
---------------------------------------------------------------------------

    \6\ Wyoming Air Quality Standards and Regulations (WAQSR), 
Chapter 8, Section 3, General Conformity (as approved by the EPA; 78 
FR 49685, August 15, 2013.)
---------------------------------------------------------------------------

V. The EPA's Proposed Action

    For the reasons explained in Section IV, we are proposing to 
approve the LMP for the Sheridan NAA and the State's request to 
redesignate the Sheridan NAA from nonattainment to attainment for the 
1987 24-hour PM10 NAAQS. Additionally, the EPA is proposing 
to determine that the Sheridan NAA has attained the NAAQS for 
PM10. This determination is based upon monitored air quality 
data for the PM10 NAAQS during the years 2014-2016. Lastly, 
the EPA is proposing to approve the Sheridan LMP as meeting the 
appropriate transportation conformity requirements found in 40 CFR 93, 
subpart A.

VI. Statutory and Executive Orders Review

    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; this proposed action 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, Oct. 4, 1993);
     Is not expected to be an Executive Order 13771 regulatory 
action because this action is not significant 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 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).

[[Page 4022]]

List of Subjects in 40 CFR Part 52

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

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

    January 22, 2018.
Douglas H. Benevento,
Regional Administrator, Region 8.
[FR Doc. 2018-01493 Filed 1-26-18; 8:45 am]
 BILLING CODE 6560-50-P