Document ID: EPA-R08-OAR-2016-0585-0001
Agency: epa
Document Type: Proposed Rule
Title: Approval and Promulgation of Air Quality Implementation Plans; State of Utah; Logan Nonattainment Area Fine Particulate Matter State Implementation Plan for Attainment of 2006 24-Hour Fine Particulate Matter National Ambient Air Quality Standards
Posted Date: 2017-12-04T05:00Z

[Federal Register Volume 82, Number 231 (Monday, December 4, 2017)]
[Proposed Rules]
[Pages 57183-57193]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-25960]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2016-0585; FRL-9971-07-Region 8]

Approval and Promulgation of Air Quality Implementation Plans; 
State of Utah; Logan Nonattainment Area Fine Particulate Matter State 
Implementation Plan for Attainment of 2006 24-Hour Fine Particulate 
Matter National Ambient Air Quality Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve the emissions inventory, modeled attainment demonstration, 
determination for Major Stationary Source Reasonably Available Control 
Technology (RACT), determination for On-Road Mobile Sources Reasonably 
Available Control Measures (RACM), determination for Cache County 
Inspection and Maintenance (I/M) Program as additional reasonable 
measures, determination for Off-Road Mobile Sources RACM, and the 2015 
Motor Vehicle Emission Budgets (MVEB) portions of the attainment plan 
submitted by Utah on December 16, 2014, to address Clean Air Act (CAA 
or the Act) requirements for the 2006 24-hour fine particulate matter 
(PM2.5) national ambient air quality standards (NAAQS) in 
the Logan, UT-ID Moderate PM2.5 nonattainment area. These 
actions are being taken under section 110 of the CAA.

DATES: Written comments must be received on or before January 3, 2018.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2016-0585 at https://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 the public docket. Do not submit electronically any 
information you consider to be Confidential Business Information (CBI) 
or other information, the disclosure of which is restricted by statute. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the Web, cloud, or other 
file sharing system). For additional submission methods, the full EPA 
public comment policy, information about CBI or multimedia submissions, 
and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Crystal Ostigaard, Air Program, U.S. 
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 
Wynkoop Street, Denver, Colorado 80202-1129, (303) 312-6602, 
[email protected].

SUPPLEMENTARY INFORMATION: 

I. General Information

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

    a. Submitting CBI. Do not submit CBI to the EPA through 
www.regulations.gov or email. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in 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 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.
    b. Tips for Preparing Your Comments. When submitting comments, 
remember to:
    1. Identify the rulemaking by docket number and other identifying 
information (subject heading, Federal Register date and page number).
    2. Follow directions--The agency may ask you to respond to specific 
questions or organize comments by referencing a Code of Federal 
Regulations (CFR) part or section number.
    3. Explain why you agree or disagree; suggest alternatives and 
substitute language for your requested changes.
    4. Describe any assumptions and provide any technical information 
and/or data that you used.
    5. If you estimate potential costs or burdens, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    6. Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    7. Explain your views as clearly as possible, avoiding the use of 
profanity or personal threats.

[[Page 57184]]

    8. Make sure to submit your comments by the comment period deadline 
identified.

II. Background

    On October 17, 2006 (71 FR 61144), the EPA revised the level of the 
24-hour PM2.5 NAAQS, lowering the primary and secondary 
standards from the 1997 standard of 65 micrograms per cubic meter 
([micro]g/m\3\) to 35 [micro]g/m\3\. On November 13, 2009 (74 FR 
58688), the EPA designated three nonattainment areas in Utah for the 
24-hour PM2.5 NAAQS of 35 [micro]g/m\3\. These are the Salt 
Lake City, Utah (UT); Provo, UT; and Logan, UT-Idaho (ID) nonattainment 
areas.
    The Logan, UT-ID PM2.5 nonattainment area, also called 
the Cache Valley, is composed of portions of Cache County, UT and 
Franklin County, ID. The Cache Valley is an isolated, bowl-shaped 
valley measuring approximately 60 kilometers north to south and 20 
kilometers east to west and almost entirely surrounded by mountain 
ranges. The Wellsville Mountains lie to the west, and on the east lie 
the Bear River Mountains; both are northern branches of the Wasatch 
Range. The State considers topography as a barrier to air movement 
during the conditions which lead to elevated concentrations of fine 
particulates and as the primary factor in determining where the 
population is located. The low-lying valleys which trap air during 
winter-time temperature inversions are also the regions within which 
people live. Additional information pertaining to the unique issues 
associated with the Logan, UT-ID nonattainment area and studies 
completed on inversions can be found in the 9-factor analysis for Utah 
and Idaho in the November 13, 2009 (74 FR 58688) action titled ``Air 
Quality Designations for the 2006 24-Hour Fine Particulate 
(PM2.5) National Ambient Air Quality Standards.''
    The EPA originally issued a rule in 2007 \1\ regarding 
implementation of the PM2.5 NAAQS for the nonattainment area 
requirements specified in CAA title I, part D, subpart 1. Under subpart 
1, Utah was required to submit an attainment plan for each area no 
later than three years from the date of nonattainment designation. 
These plans needed to provide for the attainment of the 
PM2.5 standards as expeditiously as practicable, but no 
later than five years from the date the areas were designated 
nonattainment.
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    \1\ 72 FR 20586; April 25, 2007.
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    Following the November 13, 2009 designation of nonattainment for 
PM2.5, Utah developed a draft PM2.5 attainment 
plan intended to meet the requirements of subpart 1. The EPA submitted 
written comments dated November 1, 2012, to the Utah Division of Air 
Quality (UDAQ) on the draft PM2.5 SIP, technical support 
document (TSD), area source rules, and point source rules found in 
Section IX, Part H.\2\ Utah submitted a revised PM2.5 
attainment plan for the Logan, UT-ID nonattainment area on December 14, 
2012.
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    \2\ An ``area source'' is ``any small residential, governmental, 
institutional, commercial, or industrial fuel combustion operation; 
onsite solid waste disposal facility; motor vehicle], aircraft 
vessel or other transportation facilit[y] or other miscellaneous 
source identified'' through specified inventory techniques. 40 CFR 
51.100(l). A ``point source'' is any stationary source emitting 
above certain thresholds. 40 CFR 51.100(k).
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    On January 4, 2013, the U.S. Court of Appeals for the District of 
Columbia held that the EPA should have implemented the 2006 
PM2.5 24-hour standards, as well as the other 
PM2.5 NAAQS, based on both CAA title I, part D, subpart 1 
and subpart 4. Under subpart 4, all nonattainment areas are initially 
classified as Moderate, and Moderate area attainment plans must address 
the requirements of subpart 4 as well as subpart 1. Additionally, 
subpart 4 sets a different SIP submittal due date and attainment year. 
For a Moderate area, the attainment SIP is due 18 months after 
designation and the attainment year is as expeditiously as practicable, 
but no later than the end of the sixth calendar year after designation.
    On June 2, 2014 (79 FR 31566), the EPA finalized the Identification 
of Nonattainment Classification and Deadlines for Submission of State 
Implementation Plan (SIP) Provisions for the 1997 Fine Particulate 
(PM2.5) National Ambient Air Quality Standard (NAAQS) and 
2006 PM2.5 NAAQS (``the Classification and Deadlines 
Rule''). This rule classified as Moderate the areas that were 
designated in 2009 as nonattainment, and set the attainment SIP 
submittal due date for those areas at December 31, 2014. Additionally, 
this rule established the Moderate area attainment date of December 31, 
2015.
    After the court's 2013 decision, Utah amended its attainment plan 
to address the requirements of subpart 4. On December 2, 2013, and 
October 30, 2014, the EPA provided comments on Utah's revised draft 
PM2.5 SIPs, including the TSD and emissions limits in 
Section IX, Part H. Subsequently, on December 16, 2014, UDAQ withdrew 
all prior Logan, UT-ID PM2.5 Moderate SIP submissions and 
submitted a subpart 1 and subpart 4 PM2.5 Moderate SIP, 
which is one of the submissions we are proposing to act on today.\3\
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    \3\ The Salt Lake City, UT and Provo, UT Moderate 
PM2.5 SIPs attainment plans, including requirements 
regarding RACM under CAA subparts 1 and 4 of part D, title I of the 
Act, will be acted on separately.
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    On August 24, 2016, the EPA finalized the Fine Particulate Matter 
National Ambient Air Quality Standards: State Implementation Plan 
Requirements (``PM2.5 Implementation Rule''), 81 FR 58010, 
which partially addressed the January 4, 2013 court ruling. The final 
PM2.5 Implementation Rule details how air agencies can meet 
the statutory SIP requirements under subparts 1 and 4 that apply to 
areas designated nonattainment for any PM2.5 NAAQS, such as: 
General requirements for attainment plan due dates and attainment 
demonstrations; provisions for demonstrating reasonable further 
progress (RFP); quantitative milestones; contingency measures; 
Nonattainment New Source Review (NNSR) permitting programs; and RACM 
(including RACT). The statutory attainment planning requirements of 
subparts 1 and 4 were established to ensure that the following goals of 
the CAA are met: (i) That states implement measures that provide for 
attainment of the PM2.5 NAAQS as expeditiously as 
practicable; and, (ii) that states adopt emissions reduction strategies 
that will be the most effective at reducing PM2.5 levels in 
nonattainment areas.
    On September 8, 2017 (82 FR 42447), the EPA granted two, one-year 
extensions of the Moderate attainment date for the Logan, UT-ID 
Moderate PM2.5 nonattainment area until December 31, 2017.

III. Clean Air Act Requirements for PM2.5 Moderate 
Nonattainment Area Plans

A. PM2.5 Moderate Area Plan Requirements

    Upon designation as a Moderate nonattainment area under subpart 1 
and subpart 4, the CAA requires the State to submit the following 
Moderate area SIP elements:
    1. A comprehensive, accurate, current inventory of actual emissions 
from all sources of PM2.5 and PM2.5 precursors in 
the area (CAA section 172(c)(3));
    2. Provisions to assure that RACM, including RACT, for the control 
of direct PM2.5 and PM2.5 precursors shall be 
implemented no later than four years after the area is designated (CAA 
sections 172(c)(1) and 189(a)(1)(C));
    3. A demonstration (including air quality modeling) that the plan 
provides for attainment as expeditiously as

[[Page 57185]]

practicable but no later than the Moderate area attainment date;
    4. Plan provisions that require RFP (CAA section 172(c)(2));
    5. Quantitative milestones which are to be achieved every three 
years until the area is redesignated attainment and which demonstrate 
RFP toward attainment by the applicable date (CAA section 189(c));
    6. Provisions to assure that control requirements applicable to 
major stationary sources of PM2.5 also apply to major 
stationary sources of PM2.5 precursors, except where the 
State demonstrates to the EPA's satisfaction that such sources do not 
contribute significantly to PM2.5 levels that exceed the 
standard in the area (CAA section 189(e));
    7. Contingency measures to be implemented if the area fails to meet 
RFP or fails to attain by the applicable attainment date (CAA section 
172(c)(9)); and
    8. A revision to the NNSR program to set the applicable ``major 
stationary source'' thresholds to 100 tons per year (tpy) (CAA section 
302(j)).
    Moderate area PM2.5 plans must also satisfy the general 
requirements applicable to all SIP submissions under section 110 of the 
CAA, including the requirement to provide necessary assurances that the 
implementing agencies have adequate personnel, funding and authority 
under CAA section 110(a)(2)(E) and the requirements concerning 
enforcement provisions in CAA section 110(a)(2)(C).
    The EPA interprets the CAA's requirements for particulate matter 
plans under part D, title I of the Act in the following documents: (1) 
``State Implementation Plans; General Preamble for the Implementation 
of Title I of the CAA Amendments of 1990,'' 57 FR 13498 (April 16, 
1992) (``General Preamble''); (2) ``State Implementation Plans; General 
Preamble for the Implementation of Title I of the CAA Amendments of 
1990; Supplemental,'' 57 FR 18070 (April 28, 1992) (``Supplement''); 
(3) ``State Implementation Plans for Serious PM10 
Nonattainment Areas, and Attainment Date Waivers for PM10 
Nonattainment Areas Generally; Addendum to the General Preamble for the 
Implementation of Title I of the CAA Amendments of 1990,'' 59 FR 41998 
(August 16, 1994) (``Addendum''); and (4) ``Fine Particulate Matter 
National Ambient Air Quality Standards: State Implementation Plan 
Requirements,'' August 24, 2016 (81 FR 58010) (``PM2.5 
Implementation Rule''). We discuss these interpretations of the Act as 
appropriate in our evaluation of the Logan, UT-ID Moderate 
PM2.5 Plan.

B. Implementation of Reasonably Available Control Measures

    Section 172(c)(1) of the Act (from subpart 1) requires that 
attainment plans, in general, provide for the implementation of all 
RACM (including RACT) as expeditiously as practicable and shall provide 
for attainment of the national primary ambient air quality standards. 
CAA section 189(a)(1)(C) (from subpart 4) requires Moderate area 
attainment plans to contain provisions to assure that RACM is 
implemented no later than four years after designation.
    The EPA stated its interpretation of the RACT and RACM requirements 
of subparts 1 and 4 in the 1992 General Preamble for the Implementation 
of Title I of the CAA Amendments of 1990, 57 FR 13498 (Apr. 6, 1992). 
For RACT, the EPA followed its ``historic definition of RACT as the 
lowest emission limitation that a particular source is capable of 
meeting by the application of control technology that is reasonably 
available considering technological and economic feasibility.'' 57 FR 
13541. Like RACT, the EPA has historically considered RACM to consist 
of control measures that are reasonably available, considering 
technological and economic feasibility. See PM2.5 
Implementation Rule, 81 FR 58010.

IV. EPA's Evaluation of the Logan, UT-ID PM2.5 Moderate Plan

    The EPA is proposing to act on the following portions of the Logan 
Moderate PM2.5 SIP: The emissions inventory, modeled 
attainment demonstration, determination for Major Stationary Source 
RACT, determination for On-Road Mobile Sources RACM, determination for 
Cache County I/M Program as additional reasonable measures, 
determination for Off-Road Mobile Sources RACM, and 2015 MVEB.

A. Emissions Inventory

1. Requirements for Emissions Inventories
    CAA section 172(c)(3) requires that each SIP include a 
``comprehensive, accurate, current inventory of actual emissions from 
all sources of the relevant pollutant or pollutants in [the] area. . . 
.'' By requiring an accounting of actual emissions from all sources of 
the relevant pollutants in the area, this section provides for the base 
year inventory to include all emissions that contribute to the 
formation of a particular NAAQS pollutant. For the 2006 
PM2.5 standards, this includes direct PM2.5 as 
well as the precursor emissions to the formation of secondary 
PM2.5: Nitrogen oxide (NOX), sulfur dioxide 
(SO2), volatile organic compounds (VOC), and ammonia 
(NH3). Direct PM2.5 includes condensable and 
filterable particulate matter. Additionally, a state must include in 
its SIP submission documentation explaining how the emissions data were 
calculated. In estimating mobile source emissions, a state should use 
the latest emissions models and planning assumptions available at the 
time the SIP is developed.
    In addition to the base year inventory submitted to meet the 
requirements of CAA section 172(c)(3), the State must also submit 
future inventories for the projected attainment year and any other year 
of significance for meeting applicable CAA requirements. By attainment 
projected inventories, we mean the projected emissions inventories for 
future years that account for, among other things, the ongoing effects 
of economic growth and adopted emissions control requirements. The SIP 
should include documentation to explain how the emissions projections 
were calculated.
2. Emissions Inventories in the Logan, UT-ID PM2.5 Moderate 
Plan
    The base year inventory should represent typical conditions at a 
recent point in time, and becomes the basis for comparisons with all 
projections into the future. The foundation that UDAQ used for each of 
these specific inventories is the 2008 triennial inventory, which was 
the most recent comprehensive inventory submitted to the EPA under 
subpart A of 40 CFR part 51. Utah used the 2008 inventory to back-cast 
and adjust for certain episodic conditions, and forecast a 
representation of more typical conditions to develop the projected 
inventories.
    The Logan, UT-ID nonattainment area emissions inventory includes 
emissions estimates from point sources, area sources, on-road mobile 
sources, and off-road mobile sources. The methodologies used to derive 
the 2010 base year inventory for PM2.5 are as follows:
     The point source emissions inventory is based on the 2008 
triennial National Emissions Inventory (NEI) data of actual emissions 
reported by all permitted facilities. UDAQ used data from the Regional 
Economic Models, Inc. (REMI) to project the 2008 actual point source 
emissions to 2010.
     Activity data was used to calculate emissions for area 
source categories. This data includes population, employment, vehicle 
miles traveled

[[Page 57186]]

(VMT), fuel usage, agriculture, and other estimates covering a wide 
range of activities, in conjunction with the 2008 triennial NEI.
     The inventory for the on-road mobile source category 
includes emissions for mobile sources such as trucks, cars, buses, and 
motorcycles. It was prepared by UDAQ using the EPA's Motor Vehicle 
Emissions Simulator (MOVES2010a), the most current version of the model 
available at the time the inventory was prepared, in conjunction with 
information generated by travel demand models such as vehicle speeds 
and miles traveled.
     The non-road mobile source category includes miscellaneous 
non-road engines, aircraft, and locomotives. Miscellaneous non-road 
emissions were computed by using the EPA NONROAD Model, version 
2008.1.0. Locomotive emissions were estimated by applying the EPA 
emission factors to the total amount of fuel used by locomotives. 
Aircraft emissions were estimated by applying aircraft specific 
activity data and the Emissions Dispersion Modeling System (EDMS), 
version 5.1.2.
     Paved road emissions (coarse particulate matter 
(PM10) and PM2.5 fugitive dust) were estimated by 
UDAQ based on the EPA's January 2011 version of AP-42, Section 13.2.1.
    Table 1 below provides a summary of winter daily average 
inventories of source categories for direct PM2.5 and 
PM2.5 precursors for the 2010 base year and 2015 projected 
year. The base year inventory provides the basis for the control 
measure analysis in the Logan, UT-ID Moderate PM2.5 SIP and 
the projected year inventory provides the model projection for emission 
reductions found in the Logan, UT-ID Moderate PM2.5 SIP.

  Table 1--Logan, UT-ID Typical Winter Inversion Weekday in Tons per Day (tpd) of Source Categories for Direct PM2.5 and PM2.5 Precursors for the 2010
                                                          Baseline Year and 2015 Projected Year
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                                                                     2010                                                   2015
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              Source category                 Direct                                                 Direct
                                              PM2.5       NOX        SO2        VOC        NH3       PM2.5       NOX        SO2        VOC        NH3
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Area Sources..............................       0.54       1.63       0.26       4.16       4.31       0.40       1.59       0.27       3.75       4.08
Mobile Sources............................       0.67       6.48       0.04       4.99       0.12       0.32       4.49       0.03       3.36       0.10
Non-Road Mobile Sources...................       0.13       1.15       0.02       2.28       0.00       0.10       0.81       0.01       1.77       0.00
Point Sources.............................       0.00       0.02       0.00       0.63       0.00       0.00       0.00       0.00       0.00       0.00
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    Total *...............................       1.35       9.28       0.32      12.06       4.43       0.82       6.89       0.31       8.88       4.19
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* Totals might have slight deviations from the sum of the source categories due to rounding.

    The composition of the Area Source Category in the table above 
includes: Agriculture--livestock waste; bulk gasoline terminals; 
commercial cooking; dust--construction dust; fuel combination--
commercial/institutional--coal, natural gas, oil, and other; fuel 
combination--residential--oil, other, and wood; gas stations, 
industrial processes--not elsewhere classified (NEC); miscellaneous 
non-industrial NEC; mobile--non-road equipment--diesel; solvent--
consumer and commercial solvent use, degreasing, dry cleaning, graphic 
arts, industrial surface coating and solvent use, non-industrial 
surface coating; and waste disposal.
3. The EPA's Evaluation and Proposed Action: Base Year and Projected 
Emissions Inventories
    The PM2.5 Implementation Rule sets forth several 
requirements for the base year inventory and projected year inventory 
for Moderate area attainment plans. 40 CFR 51.1008(a)(1) and 40 CFR 
51.1008(a)(2), respectively. The EPA has also issued guidance for the 
preparation of emissions inventories for implementation of the 
PM2.5 and ozone standards, along with regional haze 
requirements.\4\ We propose to determine that the base year and 
projected year inventories meet the requirements in the CAA and 
PM2.5 Implementation Rule and was prepared consistently with 
the recommendations in the guidance.
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    \4\ ``Emissions Inventory Guidance for Implementation of Ozone 
and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations,'' Office of Air Quality 
Planning and Standards, EPA-454/R-05-001 (August 2005).
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    Specifically, the base year inventory satisfies each requirement 
found in 40 CFR 51.1008(a)(1). First, the base year of 2010 was not one 
of the three years (2006-2008) used for designation of the area as 
nonattainment. See 40 CFR 51.1008(a)(1)(i). However, the state has 
justified 2010 as a technically appropriate inventory year, and the use 
of a later year is consistent with the statutory requirement in section 
172(c)(3) to use a ``current'' inventory. Second, the inventory 
represents actual, average season-day emissions. 40 CFR 
51.1008(a)(1)(ii) and (a)(1)(iii). Third, the inventory provides 
emissions of all precursors of PM2.5. 40 CFR 
51.1008(a)(1)(iv). Fourth, emissions of point sources are reported 
according to thresholds found in 40 CFR part 51, subpart A. 40 CFR 
51.1008(a)(1)(v).
    The projected year inventory satisfies each requirement in 40 CFR 
51.1008(a)(2). First, the 2015 projected year inventory was the most 
expeditious year that showed modeled PM2.5 concentrations 
below the 24-hour PM2.5 NAAQS. 40 CFR 51.1008(a)(2)(i). 
Second, the projected emission values were derived from the same 
sources included in the base year inventory and included projected 
emissions based on growth and contraction pertaining to controls and 
other potential causes. 40 CFR 51.1008(a)(2)(ii). Third, the temporal 
period of projected emissions was the same as the base year inventory, 
average season-day. 40 CFR 51.1008(a)(2)(iii). Fourth, the inventory 
provides emissions of all precursors of PM2.5. 40 CFR 
51.1008(a)(2)(iv). Fifth, all sources (point, stationary nonpoint, and 
mobile sources) were included in the projected inventory at the same 
level of detail found in the base year inventory. 40 CFR 
51.1008(a)(2)(v) and (a)(2)(vi).
    The base year inventory in the Logan, UT-ID Moderate 
PM2.5 SIP is based on the most current and accurate 
information available to the State at the time the SIP was being 
developed. Additionally, the base year and projected inventories met 
all minimum requirements found in 40 CFR 51.1008(a)(1) and (2), and the 
inventories addressed all source categories in the Logan, UT-ID

[[Page 57187]]

nonattainment area and were developed consistent with the EPA's 
inventory guidance.\5\ For these reasons, we are proposing to approve 
the 2010 base year emissions inventory and the 2015 projected emissions 
inventory in the Logan, UT-ID PM2.5 SIP as meeting the 
requirements of CAA section 172(c)(3). We are also proposing to find 
that the base year and projected inventories in the SIP provide an 
adequate basis for development of the Logan, UT-ID Moderate 
PM2.5 SIP.
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    \5\ Utah Moderate PM2.5 SIP TSD, Chapter 1--Inventory 
General, Section b--Inventory Preparation Plan. The scope for UDAQ's 
PM2.5 Emission Inventory Preparation Plan includes: EPA's 
``Emission Inventory Improvement Program,'' ``Emissions Inventory 
Guidance for Implementation of Ozone and Particulate Matter National 
Ambient Air Quality Standards (NAAQS) and Regional Haze 
Regulations'' dated August 2005, ``Guidance on the Use of Models and 
Other Analyses for Demonstrating Attainment of Air Quality Goals for 
Ozone, PM2.5, and Regional Haze'' dated April 2007, and 
``Guidance for Creating Annual On-Road Mobile Source Emission 
Inventories for PM2.5 Nonattainment Areas for Use in SIPs 
and Conformity'' dated August 2005. These documents helped to 
facilitate the collection of point, area, mobile, biogenic, and 
geogenic emission inventory data.
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B. Modeled Attainment Demonstration

1. Requirements for the Modeled Attainment Demonstration
    Air quality modeling is used to establish emissions attainment 
targets, the combination of emissions of PM2.5 and 
PM2.5 precursors that the area can accommodate and still 
attain the standard, and to assess whether the proposed control 
strategy will result in attainment of the standard. Air quality 
modeling is performed for a base year and compared to air quality 
monitoring data collected during that year in order to determine model 
performance. Once the model performance is determined to be acceptable, 
future year changes to the emissions inventory are simulated with the 
model to determine the relationship between emissions reductions and 
changes in ambient air quality. To project future design values (FDVs), 
the model response to emission reductions, in the form of Relative 
Response Factors (RRFs), is applied to monitored design values from the 
base year.
    At the time the Logan, UT-ID Moderate PM2.5 SIP was 
developed, the EPA's recommendations for model input preparation, model 
performance evaluation, use of the model output for the attainment 
demonstration and modeling documentation were described in Guidance on 
the Use of Models and Other Analyses for Demonstrating Attainment of 
Air Quality Goals for Ozone, PM2.5, and Regional Haze, EPA-
454/B-07-002, April 2007 (``Modeling Guidance Update'').\6\
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    \6\ The EPA Modeling Guidance and Modeling Guidance Update are 
available on EPA's SCRAM Web site, Web page: http://www.epa.gov/scram001/guidance_sip.htm.
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    The EPA recommends that states prepare a modeling protocol as part 
of their modeled attainment demonstration, and the Modeling Guidance 
describes the topics to be addressed in the modeling protocol. A 
modeling protocol should detail and formalize the procedures for 
conducting all phases of the modeling analysis, such as describing the 
background and objectives, creating a schedule and organizational 
structure, developing the input data, conducting model performance 
evaluations, interpreting modeling results, describing procedures for 
using the model to demonstrate whether proposed strategies are 
sufficient to attain the applicable standard, and producing 
documentation to be submitted for the EPA Regional Office review and 
approval prior to actual modeling.
    In addition to a modeled attainment demonstration, which focuses on 
locations with an air quality monitor, EPA's Guidance describes an 
Unmonitored Area Analysis (UAA). This analysis is intended to ensure 
that a control strategy leads to reductions in PM2.5 at 
other locations that have no monitor but that might have base year and 
future baseline (projection year) ambient PM2.5 levels 
exceeding the standard.
    Under the PM2.5 Implementation Rule, the attainment 
demonstration must show that the projected attainment date is as 
expeditious as practicable. 40 CFR 51.1392(a)(1). The demonstration 
must meet the general modeling requirements in Appendix W to part 51 
and must include the emission inventory data, modeling results, and 
emission reduction analyses that were used in the demonstration. 40 CFR 
51.1392(a)(2). The base year for the emissions inventory must be one of 
the three years used for designation or another technically appropriate 
year that the state has justified. 40 CFR 51.1392(a)(3). Finally, the 
attainment demonstration must be consistent with the control strategy 
in the attainment plan. 40 CFR 51.1392(a)(4).
2. Modeled Attainment Demonstration in the Logan, UT-ID 
PM2.5 Moderate Plan
    UDAQ conducted a technical analysis to support the development of 
the Logan, UT-ID Moderate PM2.5 SIP. Their analyses included 
preparation of emissions inventories, meteorological data, and the 
application and evaluation of a regional photochemical model. UDAQ's 
air quality analyses were conducted using the Community Multiscale Air 
Quality (CMAQ) Model version 4.7.1, with emissions inputs generated 
using the Sparse Matrix Operator Kernel Emissions (SMOKE) processing 
system, and meteorological inputs developed using the Weather Research 
and Forecasting (WRF) model.
    The modeling protocol for the Moderate PM2.5 SIP is 
contained in the docket for this action and includes descriptions of 
the photochemical modeling. Additional description of the photochemical 
modeling is covered in the Weight of Evidence Analysis (WOEA).\7\ The 
protocol was reviewed by the EPA and covers all of the topics 
recommended in the Modeling Guidance Update.
---------------------------------------------------------------------------

    \7\ Chapter 4--Air Quality Modeling of the Logan, UT-ID Moderate 
PM2.5 SIP TSD.
---------------------------------------------------------------------------

    The air quality modeling and results are summarized in Chapter 5--
Attainment Demonstration of the Logan, UT-ID PM2.5 SIP and 
in Chapter 4--Air Quality Modeling of the TSD. Additionally, the Logan, 
UT-ID PM2.5 SIP included a UAA in Chapter 4 of the TSD 
within the WOEA (section 1.5).
3. Evaluation of the Air Quality Modeling in the Logan, UT-ID 
PM2.5 SIP
    As mentioned above, the attainment demonstration must show that the 
Moderate nonattainment area will attain the standard as expeditiously 
as practicable but no later than the end of the sixth calendar year 
after the area's designation. The Logan, UT-ID Moderate 
PM2.5 nonattainment area attainment date was December 31, 
2015. As the Moderate PM2.5 attainment plan for the Logan, 
UT-ID nonattainment area was due December 31, 2014 (79 FR 31566; June 
2, 2014), one year before the six-year mark, the EPA proposes to 
determine that the projected attainment date of December 31, 2015, was 
as expeditious as practicable. We also note that one of the control 
measure implemented in the Logan, UT-ID nonattainment area, the I/M 
program, was not fully implemented until 2015. This supports the 
conclusion that the attainment date, December 31, 2015, was as 
expeditiously as practicable.
    The EPA proposes to approve the attainment demonstration as meeting 
general modeling requirements in Appendix W. The joint Utah and Idaho 
modeling included in Chapter 4 of the TSD and Chapter 5 of the Logan, 
UT-ID Moderate PM2.5 SIP followed applicable EPA modeling 
guidance in

[[Page 57188]]

predicting that state and federal control measures to address point 
sources, area sources, on-road mobile sources, and off-road mobile 
sources would bring PM2.5 concentrations below 35 [micro]g/
m\3\ by December 31, 2015, in the Logan, UT-ID nonattainment area. The 
air quality model performance appears generally acceptable and usually 
within stated performance goals; speciation and composition of the 
modeled PM2.5 matches the observed speciation, with good 
agreement in the magnitude of PM2.5 and good replication of 
the episodic buildup and clear out of PM2.5; however, the 
meteorological model does not always accurately simulate the intensity 
and persistence of cold air pool inversion conditions, and as a result, 
the model sometimes clears out the simulated PM2.5 too early 
at the end of an episode.
    We note that the PM2.5 Implementation Rule provides that 
a state's modeled attainment demonstration must establish that an area 
will attain the NAAQS by the projected attainment date. However, for 
purposes of modeling, a state may elect to demonstrate that the area 
will meet the numerical level of the NAAQS for the attainment year (81 
FR 58010, at page 58054). The EPA authorizes this approach because of 
the potential availability of extensions of the Moderate area 
attainment date under relevant provisions section 188(d) of the CAA. In 
other words, if ambient data show attainment-level concentrations in 
the applicable statutory attainment year, the state may be eligible for 
up to two one-year extensions of the attainment date. See 40 CFR 
51.1005. Using this provision, a state may be able to attain the NAAQS 
by the extended attainment date, even if the measured design value (a 
three-year average) for an area does not meet the NAAQS by the end of 
the 6th calendar year after designation. For this reason, the 
PM2.5 Implementation Rule indicates that it is acceptable 
for a state to model air quality levels for the final statutory 
attainment year in which the area is required to attain the standard, 
in this case, 2015. In the Logan, UT-ID nonattainment area, both 
measured and modeled PM2.5 concentrations in 2015 were 
consistent with meeting the numerical level of the NAAQS in both Utah 
and Idaho, thus confirming the attainment demonstration.\8\
---------------------------------------------------------------------------

    \8\ The Logan, UT-ID Moderate PM2.5 nonattainment 
area monitor located in Logan, UT, recorded a valid 2015 98th 
percentile of 29.0 [micro]g/m\3\. See the document titled ``May 8, 
2017 Logan, UT-ID PM2.5 Memo'' in the docket to this 
action.
---------------------------------------------------------------------------

    Additionally, UDAQ included a UAA in the WOEA found in Chapter 4 of 
the TSD. The UAA showed that five grid-cells north of the Franklin, ID 
monitor had calculated future design values (FDVs) over 35.5 [micro]g/
m\3\. UDAQ was not sure why the predicted peak PM2.5 
concentrations were high because there were no large point sources in 
the county, or any other emissions sources that could produce the level 
of emissions in the specific grid-cells to cause this concentration. 
The WOEA explains that the uncertainty in UDAQ's UAA method may be 
responsible for the high values north/northwest of the Franklin, ID 
monitor. EPA modeling guidance \9\ suggests using the Model Attainment 
Test Software (MATS) post-processor to perform a UAA. However, the MATS 
version 2.5.1 that was available when the Logan, UT-ID Moderate 
PM2.5 SIP was developed did not have the ability to perform 
a UAA for daily average PM2.5. As a result, UDAQ attempted 
to implement a UAA methodology for the Logan, UT-ID Moderate 
PM2.5 nonattainment area UAA that was comparable to what was 
recommended by the EPA guidance, but the gradient adjustment and 
speciation techniques were necessarily simpler.
---------------------------------------------------------------------------

    \9\ April 2007; EPA-454/B-07-002; Guidance on the Use of Models 
and Other Analyses for Demonstrating Attainment of Air Quality Goals 
for Ozone, PM2.5, and Regional Haze.
---------------------------------------------------------------------------

    The EPA worked with UDAQ to develop the methodology for the UAA in 
the Logan, UT-ID Moderate PM2.5 nonattainment area and 
agrees with UDAQ's conclusion that there were no large point sources 
within the high concentration grid-cells and the potentially high 
values north/northwest of the Franklin, ID monitor are possibly due to 
the uncertainty inherent in UDAQ's UAA method. Additionally, the EPA 
reviewed available monitoring data for 2015 at the Logan and Franklin 
monitors for which the 98th percentiles are 29.0 [micro]g/m\3\ and 18.8 
[micro]g/m\3\, respectively. The monitoring data indicates that the 
high values in the UAA grid cells north/northwest of the Franklin 
monitor are likely an anomaly and the EPA will continue to work with 
UDAQ to refine their UAA method for future use.
    The EPA is therefore proposing to approve the attainment 
demonstration portion of the Logan, UT-ID Moderate PM2.5 
SIP.

C. Reasonably Available Control Measures/Reasonably Available Control 
Technology and Additional Reasonable Measures

1. Requirements for the RACM/RACT and Additional Measures
    As mentioned above, section 172(c)(1) of the Act (from subpart 1) 
requires that attainment plans, in general, provide for the 
implementation of all RACM (including RACT) as expeditiously as 
practicable. Section 189(a)(1)(C) (from subpart 4) requires Moderate 
area plans to include provisions to assure that RACM is implemented no 
later than four years after designation. The Logan, UT-ID area was 
designated nonattainment for the 2006 24-hour PM2.5 NAAQS on 
November 13, 2009 (74 FR 58688). However, the Logan, UT-ID 
nonattainment area was not classified as Moderate under subpart 4 until 
the EPA published the Classification and Deadlines Rule on June 2, 2014 
(79 FR 31566). Because the EPA designated the Logan, UT-ID 
nonattainment area effective December 14, 2009, the area was required 
to implement RACM/RACT no later than December 14, 2013.
    The PM2.5 Implementation Rule defines RACM (including 
RACT) as any technologically and economically feasible measure that can 
be implemented in whole or in part within four years after the 
effective date of designation of a PM2.5 nonattainment area 
and that achieves permanent and enforceable reductions in direct 
PM2.5 emissions and/or PM2.5 precursor emissions 
from sources in the area.
    Under the PM2.5 Implementation Rule, the state must 
first identify all sources of emissions of direct PM2.5 and 
all PM2.5 precursors (NOX, SO2, VOC, 
and NH3) in the nonattainment area, in accordance with the 
emission inventory requirements described above. 40 CFR 51.1010(a)(1). 
The state must then identify all potential control measures to reduce 
emissions from those source categories, except for source categories or 
major stationary sources for which the state submits an acceptable 
precursor demonstration. 40 CFR 51.1010(a)(2). The state next 
determines whether the identified potential control measures are 
technologically feasible and whether any of the identified 
technologically feasible control measures are economically feasible. 40 
CFR 51.1010(a)(3). The state must provide a detailed written 
justification for any potential control measure that has been excluded 
as technologically or economically infeasible. 40 CFR 
51.1010(a)(3)(iii). The state may also eliminate potential control 
measures

[[Page 57189]]

that would take longer than six years to implement. 40 CFR 
51.1010(a)(3)(i).
    Section 172(c)(6) of the Act requires states to implement ``other 
measures'' necessary to provide for timely attainment in an area. The 
PM2.5 Implementation Rule interprets this provision to 
require ``additional reasonable measures,'' which are those measures 
and technologies that can be applied at sources in the nonattainment 
area that are otherwise technologically and economically feasible but 
can only be implemented in whole or in part later than four years after 
designation.\10\
---------------------------------------------------------------------------

    \10\ 81 FR 58010, 58043; August 24, 2016.
---------------------------------------------------------------------------

2. RACM/RACT in the Logan, UT-ID PM2.5 Moderate Plan
a. Major Stationary Sources
    In developing the emissions inventories underlying the SIP, UDAQ 
used the criteria of 40 CFR part 51, subpart A for air emissions 
reporting requirements to establish a 100 tons per year (tpy) threshold 
for identifying a sub-group of major stationary sources that would be 
evaluated individually for the establishment of emissions limits. Under 
40 CFR 51.1000, the definition for major stationary source means ``Any 
stationary source of air pollutant(s) that emits, or has the potential 
to emit, 100 tpy or more of direct PM2.5 or any 
PM2.5 precursor in any Moderate nonattainment area for the 
PM2.5 NAAQS, or 70 tpy or more of direct PM2.5 or 
any PM2.5 precursor in any Serious nonattainment area for 
the PM2.5 NAAQS.'' \11\ UDAQ used the Moderate threshold for 
emissions of direct PM2.5 and all PM2.5 
precursors for all major stationary sources in the modeling domain. 
Additionally, UDAQ applied the 100 tpy threshold to the sources' 
potential to emit as well as their actual emissions. UDAQ determined 
that according to Moderate area threshold, Pepperidge Farm Inc., was 
the only source included on this list that is located in the Logan-UT-
ID nonattainment area. Table 2 provides actual emission totals in tpy 
for the Pepperidge Farm Inc., plant for 2008.
---------------------------------------------------------------------------

    \11\ 81 FR 58010, 58152; August 24, 2016.

                     Table 2--Pepperidge Farm Incorporated 2008 Criteria Pollutant Inventory
----------------------------------------------------------------------------------------------------------------
                    Process                         PM2.5         SO2          NOX          VOC          NH3
----------------------------------------------------------------------------------------------------------------
                                      2008 Plantwide Emission Totals (tpy)
----------------------------------------------------------------------------------------------------------------
Process & Fuel Emissions.......................         0.48         0.03         5.20         0.29         0.03
Evaporative Emissions..........................  ...........  ...........  ...........         0.32  ...........
Engines........................................         0.02         0.01         0.13         0.01         0.00
Bakery.........................................  ...........  ...........  ...........       149.58  ...........
                                                ----------------------------------------------------------------
    Totals.....................................         0.50         0.04         5.33       150.20         0.03
----------------------------------------------------------------------------------------------------------------

    UDAQ determined that data from the REMI would be used to project 
the 2008 actual major stationary source emissions to 2010. On March 23, 
2012, Pepperidge Farm Inc., applied to be designated as a synthetic 
minor source and on May 21, 2012, UDAQ concurred and issued a 
construction permit that restricted emissions below the major 
stationary source threshold. Specifically, VOC emissions were limited 
to 93.81 tpy per rolling 12-month period. Since Pepperidge Farm Inc. 
was designated as a synthetic minor source in 2012, the source was not 
included in the 2015 projection inventory as a major stationary source, 
but in the area source inventory. Table 3 below shows emissions in tons 
per day for the 2010 baseline and projected 2015 inventories.

Table 3--Pepperidge Farm Incorporated Baseline 2010 and Projected 2015 Emissions Inventories of Typical Winter Inversion Day (tpd) as a Major Stationary
                                                                         Source
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               2010                                            2015
                                                         -----------------------------------------------------------------------------------------------
                                                             PM2.5        NOX         VOC         SO2        PM2.5        NOX         VOC         SO2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pepperidge Farms Inc....................................       0.00        0.02        0.63        0.00   ..........  ..........  ..........  ..........
--------------------------------------------------------------------------------------------------------------------------------------------------------

    For the Logan, UT-ID Moderate PM2.5 SIP, UDAQ concluded 
that there were no major stationary sources with actual emissions or 
potential to emit 100 tpy of PM2.5 or any PM2.5 
plan precursors. As stated above, this conclusion is due to Pepperidge 
Farm Inc., reducing their emissions to be designated as a synthetic 
minor source.
b. On-Road Mobile Sources
    Through the course of the development of the Logan, UT-ID 
PM2.5 SIP, UDAQ identified a motor vehicle I/M program as 
RACM to achieve reductions of PM2.5 precursor emissions of 
NOX and VOC. Subsequently, the EPA approved the revisions 
involving amendments to Utah's SIP Section X, Vehicle Inspection and 
Maintenance Program, Part A, General Requirements and Applicability; 
the addition of Section X, Vehicle Inspection and Maintenance Program, 
Part F, Cache County in Utah's SIP; and revisions to Utah's 
Administrative Rules on September 9, 2015 (80 FR 54237).
    The EPA noted in the September 9, 2015, final rule that under 
subparts 1 and 4 of the CAA, Cache County's I/M program is not a CAA 
mandatory or required I/M program; and is therefore, not held to the 
same level of applicability requirements as found in 40 CFR part 51, 
subpart S, I/M program requirements. Within Utah's SIP, Part F of 
Section X, in conjunction with Part A of Section X, were designed by 
the County and the State to meet the minimum applicable I/M provisions 
and requirements set forth in 40 CFR 51, subpart S. It is also noted in 
Part F of Utah's SIP that although only a portion of Cache County was 
designated as nonattainment for the 2006 PM2.5 24-hour 
NAAQS, the mandatory I/M program will be implemented county-wide. The 
I/M program began operation

[[Page 57190]]

on January 1, 2014, where motor vehicles are subject to a mandatory 
biennial emissions inspection. Emissions inspections were required in 
odd-numbered years for vehicles with an odd-numbered model year and 
even-numbered years for vehicles with an even-numbered model year.
    The EPA is not revisiting the September 9, 2015 (80 FR 54237) 
approval of Cache County's I/M program with this action but is only 
acting on UDAQ's RACM analysis pertaining to this program. Within 
Chapter 5 of the TSD, UDAQ provides their review of several control 
measures and their final RACM conclusions for mobile sources in the 
Logan, UT-ID nonattainment area.
    The potential control measures identified and evaluated by UDAQ 
include: (1) A mandatory I/M program in Logan where such a program did 
not previously exist; (2) reducing the Reid vapor pressure (RVP) of 
gasoline to control VOC emissions; and (3) implementing a bundle of 
voluntary control measures (e.g., trip reduction, curtailing of 
operations/activities and driving on ``yellow'' and ``red'' air quality 
days, diesel retrofits and replacement of gasoline vehicles with 
alternate-fuel vehicles such as those running on compressed natural gas 
(CNG) or electricity, and gasoline/electric hybrids). UDAQ modeled 
these potential control measures but found that the only measure that 
provided any significant emission benefit was to include a mandatory I/
M program for the Utah portion of the Logan, UT-ID nonattainment area 
and to implement the program throughout Cache County.\12\
---------------------------------------------------------------------------

    \12\ Chapter 5--Control Strategies of the Utah Moderate 
PM2.5 SIP TSD.
---------------------------------------------------------------------------

    The preliminary cost analysis for extending the I/M program to the 
Logan, UT-ID nonattainment area shows a cost effectiveness of 
approximately $6,000 to $8,000 per ton of emissions reduced per year. 
UDAQ concluded that this was within the range of costs associated with 
other control measures which were under consideration for inclusion in 
the Logan, UT-ID PM2.5 SIP; therefore, it was economically 
feasible. Furthermore, similar programs have been successfully operated 
in Utah, Salt Lake, Davis, and Weber Counties and have proven to be 
both technologically and economically feasible.
    The EPA's motor vehicle emissions model, MOVES2010a, was used to 
identify the effectiveness of the I/M program in the Logan, UT-ID 
nonattainment area. For 2015, MOVES predicted emission reductions of 
0.21 tpd for NOX, and 0.21 tpd for VOC. UDAQ concluded that 
the I/M program met RACM and was retained as part of the overall 
control strategy for the area.
    Additionally, UDAQ provided information for On-Road Mobile programs 
that were promulgated at the federal level. The Tier 2 program was 
promulgated by the EPA on April 10, 2000 (65 FR 6698; February 10, 
2000) and was phased in between 2004 and 2008. Tier 2 set a single set 
of standards for all light duty vehicles and required refiners to 
reduce gasoline sulfur levels nationwide. UDAQ provided estimates 
provided by the EPA that the Tier 2 program would reduce oxides of 
nitrogen emission by at least 2,220,000 tpy nationwide in 2020.\13\ 
Tier 2 has also contributed in reducing VOC and direct PM emissions 
from light duty vehicles. Additional on-road mobile source emissions 
improvements that UDAQ highlights are from federal regulations for 
heavy-duty diesel vehicles. The Highway Diesel Rule, which aimed at 
reducing pollution from heavy-duty diesel highway vehicles, was 
finalized on January 18, 2001 (66 FR 5002). Under the rule, beginning 
in 2007, (with a phase-in through 2010) heavy-duty diesel highway 
vehicle emissions were required to be reduced by as much as 90 percent 
with a goal of complete fleet replacement by 2030. In order to enable 
the updated emission reduction technologies necessitated by the rule, 
beginning in 2006 (with a phase-in through 2009) refiners were required 
to begin producing cleaner-burning ultra-low sulfur diesel fuel. 
Specifically, the rule required a 97 percent reduction in sulfur 
content from 500 parts per million (ppm) to 15 ppm. This program was 
estimated to reduce PM and oxides of nitrogen from heavy duty engines 
by 90 percent and 95 percent below current standard levels set out in 
the rule, respectively.\14\ Table 4 below shows emissions in tons per 
day for the 2010 baseline and projected 2015 inventories.
---------------------------------------------------------------------------

    \13\ 65 FR 6698; February 10, 2000.
    \14\ 66 FR 5002; January 18, 2001.

               Table 4--On-Road Mobile Source Baseline 2010 and Projected 2015 Emissions Inventories of Typical Winter Inversion Day (tpd)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               2010                                            2015
                                                         -----------------------------------------------------------------------------------------------
                                                             PM2.5        NOX         VOC         SO2        PM2.5        NOX         VOC         SO2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cache County, UT........................................       0.37        6.48        4.99        0.04        0.28        4.49        3.35        0.03
--------------------------------------------------------------------------------------------------------------------------------------------------------

c. Off-Road Mobile Sources
    UDAQ did not consider any additional SIP controls for off-road 
mobile sources beyond those already promulgated at the federal level. 
Emission reductions from these federal controls were taken indirectly 
because their effectiveness has been incorporated into the NONROAD 
model. Table 5 below summarizes the 2010 base year and 2015 projection 
year annual emissions from non-road mobile sources in Cache County 
which contains the Logan, UT-ID Moderate PM2.5 nonattainment 
area.

                    Table 5--2010 Base Year and 2015 Projection Year Non-Road Mobile, Aircraft, Locomotives Emissions Inventory (tpy)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               2010                                            2015
                                                         -----------------------------------------------------------------------------------------------
                                                             PM2.5        NOX         VOC         SO2        PM2.5        NOX         VOC         SO2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cache County............................................     492.47    1,144.85       61.99        8.55      360.63      901.09       49.21        2.88
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 57191]]

    Chapter 5 of UDAQ's TSD provides a detailed description of what 
control measures were included in the modeling.
3. EPA's Evaluation of the RACM/RACT Regulations
    The EPA is proposing to approve UDAQ's determination that a RACT 
analysis for the Pepperidge Farms facility was not necessary, as the 
SIP demonstrates attainment based on the other control measures 
included in the SIP. The EPA agrees with UDAQ's underlying 
justification for including the I/M program in the Logan, UT-ID 
attainment plan. UDAQ analyzed the measure as technologically and 
economically feasible and therefore RACM; however, the measure was 
implemented in the fifth and sixth year after designation. UDAQ did not 
have the benefit of the EPA's distinction in the PM2.5 
Implementation Rule between RACM and additional reasonable measures at 
the time the RACM analysis for the I/M program was developed. We 
therefore consider the I/M program to be an additional reasonable 
measure and we are proposing to approve it as such. The EPA notes that, 
with the exception of timing of control measure implementation, the 
standard for the two types of control measures is the same: 
technological and economic feasibility. Additionally, the EPA agrees 
with UDAQ's reliance on federal on-road mobile regulations for other 
on-road mobile emission reductions in the Logan, UT-ID PM2.5 
SIP and is proposing to approve UDAQ's determination. We are also 
proposing to approve UDAQ's determination that additional off-road 
measures are not necessary given that the federal measures will provide 
further emission reductions for the Logan, UT-ID Moderate 
PM2.5 SIP. The EPA is not proposing to determine whether the 
Logan, UT-ID Moderate PM2.5 attainment SIP has fully met all 
requirements for RACM/RACT found in CAA subparts 1 and 4. This 
determination will be made at a later date.

D. Transportation Conformity and Motor Vehicle Emission Budgets

1. Requirements for Transportation Conformity and MVEBs
    Transportation conformity is required by section 176(c) of the CAA. 
The EPA's conformity rule at 40 CFR 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. 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 or any interim 
milestone. To effectuate its purpose, the EPA's conformity rule 
requires a demonstration that emissions from a Metropolitan Planning 
Organization's (MPO) Regional Transportation Plan (RTP) and 
Transportation Improvement Program (TIP), involving Federal Highway 
Administration (FHWA) or Federal Transit Administration (FTA) funding 
or approval, are consistent with the MVEB(s) contained in a control 
strategy SIP revision or maintenance plan (40 CFR 93.101, 93.118, and 
93.124). A MVEB is defined as the level of mobile source emissions of a 
pollutant relied upon in the attainment, RFP or maintenance 
demonstration to attain or maintain compliance with the NAAQS in the 
nonattainment or maintenance area. 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).
    The EPA notes that PM2.5 attainment plans should 
identify MVEBs for direct PM2.5, NOX and all 
other PM2.5 precursors where on-road mobile source emissions 
are determined to significantly contribute to PM2.5 levels 
in the nonattainment area. For the Logan, UT-ID PM2.5 SIP, 
UDAQ identified mobile source VOC emissions as a significant 
contributor to the formation of PM2.5 in the Logan, UT-ID 
PM2.5 nonattainment area. For direct PM2.5 SIP 
MVEBs, the MVEB should include direct PM2.5 motor vehicle 
emissions from tailpipes, brake wear, and tire wear. In addition, a 
state must also consider whether re-entrained road dust is a 
significant contributor and should be included in the direct 
PM2.5 MVEB.\15\ With respect to this requirement, the EPA 
reviewed information, data, and an analysis from the UDAQ that 
sufficiently documented that re-entrained road dust emissions were 
negligible and meet the criteria of 40 CFR 93.102(b)(3) for not needing 
to be included in the direct PM2.5 MVEB.
---------------------------------------------------------------------------

    \15\ 40 CFR 93.102(b) and 93.122(f); see also conformity rule 
preamble at 69 FR 40004, 40031-40036 (July 1, 2004).
---------------------------------------------------------------------------

2. MVEBs Identified in the Logan, UT-ID Moderate PM2.5 SIP
    Utah's Logan, UT-ID PM2.5 SIP Section IX. Part A.23 was 
submitted to meet the requirements of part D of title I of the CAA, 
subparts 1 and 4 for ``Moderate'' PM2.5 nonattainment areas. 
The State's attainment plan specified the maximum mobile source 
emissions of PM2.5, NOX and VOC allowed in 2015, 
the attainment year. These mobile source emissions were then identified 
by the State as the SIP's MVEBs and are to be used by the Cache MPO to 
demonstrate transportation conformity for the Cache MPO's RTP and TIP. 
The attainment plan's 2015 MVEBs include direct PM2.5, 
NOX, and VOC emissions from vehicle exhaust/evaporation, 
tire wear and brake wear. The identified MVEBs were included in Table 
7.1 of the SIP and are identified as: Direct PM2.5 is 0.32 
tpd, NOX is 4.49 tpd, and VOC is 3.23 tpd.
    We note that prior to December 31, 2015, the EPA had found the 
Logan, UT-ID PM2.5 MVEBs were adequate as described in the 
transportation conformity adequacy provisions of 40 CFR 93.118(e). 
Under 40 CFR 93.118(e)(4)(iv), we review a submitted plan to determine 
whether the MVEBs, when considered together with all other emissions 
sources, are consistent with applicable requirements for RFP, 
attainment, or maintenance (whichever is relevant to a given SIP 
submission). We described our process for determining the adequacy of 
submitted SIP MVEBs in our July 1, 2004, Transportation Conformity Rule 
Amendments (69 FR 40004). We used these resources in making our 
adequacy determination.
    On March 23, 2015, we announced receipt of the Logan, UT-ID 
PM2.5 attainment plan at the EPA's Office of Transportation 
and Air Quality (OTAQ) adequacy Web site and requested public comment 
on the adequacy of the MVEBs by April 22, 2015. We did not receive any 
comments during the comment period. We sent a letter to the UDAQ on 
June 17, 2015, stating that the submitted Logan, UT-ID PM2.5 
attainment plan SIP revision MVEBs were adequate for transportation 
conformity purposes. We announced our adequacy finding in the Federal 
Register on September 11, 2015 (80 FR 54788); effective September 28, 
2015.
3. MVEB Trading, for Purposes of Demonstrating Transportation 
Conformity, in the Logan, UT-ID PM2.5 SIP
    The EPA's transportation conformity rule allows for trading between 
direct PM2.5 and NOX and VOC precursor MVEBs, so 
long as the SIP establishes an appropriate mechanism for such 
trades.\16\
---------------------------------------------------------------------------

    \16\ 40 CFR 93.124(b).
---------------------------------------------------------------------------

    As discussed in section 7.6 ``Transportation Conformity 
PM2.5

[[Page 57192]]

Budgets'' of the Logan UT-ID PM2.5 attainment plan, the SIP 
revision establishes a MVEB trading mechanism to allow for future 
increases in on-road mobile sources direct PM2.5 emissions 
to be offset by future decreases in NOX and VOC precursor 
emissions from on-road mobile sources. These ratios were developed from 
data from the air quality attainment plan's dispersion modeling. 
Section 7.6 of the SIP and the Logan UT-ID PM2.5 attainment 
plan's Technical Support Documentation Weight-of-Evidence information 
\17\ provide the following modeling-derived trading ratios: Future 
increases in on-road mobile sources direct PM2.5 emissions 
may be offset with future decreases in NOX emissions from 
on-road mobile sources at a NOX to PM2.5 ratio of 
13.66 to 1 and/or future decreases in VOC emissions from on-road mobile 
sources at a VOC to PM2.5 ratio of 22.84 to 1.
---------------------------------------------------------------------------

    \17\ ``PM2.5 State Implementation Plan Weight-Of-
Evidence to the Model Attainment Test,'' section 1.9, pages 64 and 
65.
---------------------------------------------------------------------------

    The SIP notes that this trading mechanism will only be used by the 
Cache MPO for transportation conformity determination analyses for 
years after 2015. The SIP further notes that to ensure that the trading 
mechanism does not impact the ability to meet the NOX or VOC 
budgets, the NOX emission reductions available to supplement 
the direct PM2.5 MVEB shall only be those remaining after 
the 2015 NOX MVEB has been met. Also, the VOC emissions 
reductions available to supplement the direct PM2.5 budget 
shall only be those remaining after the 2015 VOC MVEB has been met. The 
SIP further articulates that clear documentation of the calculations 
used in the MVEB trading are to be included in the conformity 
determination analysis as prepared by the Cache MPO.
4. Evaluation and Proposed Action
    The EPA has evaluated the Logan, UT-ID PM2.5 attainment 
plan's emission inventories and attainment demonstration modeling as 
described in sections above. Based on our evaluation, we have 
determined that the direct PM2.5, NOX, and VOC 
MVEBs are appropriately derived from the SIP and are acceptable. We 
have also evaluated the description and derivation of the MVEB trading 
mechanism and the supporting data from the SIP's attainment 
demonstration modeling/Weight-Of-Evidence information and find those 
acceptable. Therefore, we are proposing to approve the Logan UT-ID 
PM2.5 attainment plan's MVEBs of direct PM2.5 of 
0.32 tpd, NOX of 4.49 tpd, and VOC of 3.23 tpd. In addition, 
we are also proposing to approve the MVEB trading mechanism as 
documented in section 7.6 of the SIP.

V. Summary of the EPA's Proposed Action

    For the reasons discussed in section IV above, under CAA section 
110(k)(3), the EPA is proposing to approve the emissions inventory, 
modeled attainment demonstration, determination for Major Stationary 
Source RACT, determination for On-Road Mobile Sources RACM, 
determination of Cache County I/M program as additional reasonable 
measures, determination for Off-Road Mobile Sources RACM, and 2015 MVEB 
for the Logan, UT-ID PM2.5 Moderate SIP.

A. Proposed Approval

    1. The EPA is proposing the following actions on the Logan, UT-ID 
PM2.5 SIP:
    a. Approve the 2010 base year and 2015 projection year emissions 
inventories;
    b. Approve the modeled attainment demonstration;
    c. Approve the RACM/RACT and additional reasonable measure 
demonstrations for on-road mobile, Cache County I/M Program, off-road 
mobile and point sources; and
    d. Approve the 2015 direct PM2.5, NOX and VOC 
MVEBs and the MVEB trading mechanism.

VI. Consideration of Section 110(l) of the CAA

    Under section 110(l) of the CAA, the EPA cannot approve a SIP 
revision if the revision would interfere with any applicable 
requirements concerning attainment and RFP toward attainment of the 
NAAQS, or any other applicable requirement of the Act. The EPA proposes 
to determine that the portions of the Logan UT-ID PM2.5 SIP 
that we are acting on are consistent with the applicable requirements 
of the Act. Furthermore, these portions do not relax any previously 
approved SIP provision; thus they do not otherwise interfere with 
attainment and maintenance of the NAAQS. In addition, section 110(l) 
requires that each revision to an implement plan submitted by a state 
shall be adopted by the state after reasonable notice and opportunity 
for public hearing. On September 3, 2014, the Air Quality Board 
proposed for public comment the Logan, UT-ID Moderate PM2.5 
attainment plan. The public comment period was held from October 1 to 
October 31, 2014, with a public hearing being held on October 20, 2014. 
On December 3, 2014, the Air Quality Board adopted the Logan, UT-ID 
Moderate PM2.5 attainment plan and became effective on 
December 4, 2014. Therefore, CAA section 110(l) requirements are 
satisfied.

VII. Incorporation by Reference

    In this rule, the EPA is proposing to include in a final EPA rule 
regulatory text that includes incorporation by reference. In accordance 
with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by 
reference the approval of portions of the Logan, UT-ID PM2.5 
Moderate SIP submitted by the state of Utah as discussed in section IV 
of this preamble. The EPA has made, and will continue to make, these 
materials generally available through www.regulations.gov and/or at the 
EPA Region 8 Office (please contact the person identified in the FOR 
FURTHER INFORMATION CONTACT section of this preamble for more 
information).

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 Act 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 approves state law as meeting federal requirements. For 
that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Order 
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

[[Page 57193]]

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).
    In addition, 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 in 40 CFR Part 52

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

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

    Dated: November 21, 2017.
Debra H. Thomas,
Acting Regional Administrator, Region 8.
[FR Doc. 2017-25960 Filed 12-1-17; 8:45 am]
 BILLING CODE 6560-50-P