[Federal Register Volume 84, Number 225 (Thursday, November 21, 2019)]
[Proposed Rules]
[Pages 64245-64260]
[FR Doc No: 2019-25176]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R08-OAR-2019-0276; FRL-10002-15-Region 8]

Approval and Promulgation of Implementation Plans; State of Utah;
Salt Lake County, Utah County, and Ogden City PM10 Redesignation to
Attainment, Designation of Areas for Air Quality Planning Purposes and
State Implementation Plan Revisions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve State Implementation Plan (SIP) revisions submitted by the
State of Utah on January 4, 2016, which include revisions to Utah's
Division of Administrative Rule (DAR) R307-110-10 and maintenance plans
for the Salt Lake County, Utah County, and Ogden City nonattainment
areas (NAAs) for particulate matter with an aerodynamic diameter less
than or equal to a nominal 10 microns (PM10), and on March
6, 2019, which include PM10 redesignation requests and
supplemental information for Salt Lake County, Utah County and Ogden
City. These submittals demonstrate that the Salt Lake County, Utah
County and Ogden City areas have attained the PM10 National
Ambient Air Quality Standards (NAAQS), request redesignation to
attainment and include maintenance plans for the areas demonstrating
attainment for fifteen years. Also, the EPA is proposing approval of
Utah's February 27, 2017 submittal, which includes rule revisions to
address our October 19, 2016 conditional approval of Utah's DAR R307-
302 revisions that were submitted May 9, 2013, May 20, 2014, and
September 8, 2015. Additionally, the EPA is proposing to approve SIP
revisions submitted by the State of Utah on February 15, 2019, with
additional non-substantive changes submitted on July 1, 2019, August
20, 2019, and October 15, 2019, which includes revisions that are
located in DAR R307-110-17 and SIP Subsections IX.H.1-2. The EPA is
taking this action pursuant to section 107, 110, and 175A of the Clean
Air Act (CAA or the Act).

DATES: Written comments must be received on or before December 23,
2019.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2019-0276, to the Federal Rulemaking Portal: 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 its
public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points

you wish to make. The EPA will generally not consider comments or
comment contents located outside of the primary submission (i.e., on
the web, cloud, or other file sharing system). For additional
submission methods, the full EPA public comment policy, information
about CBI or multimedia submissions, and general guidance on making
effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.
    Docket: All documents in the docket are listed in the
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in www.regulations.gov or in hard copy at the Air and Radiation
Division, Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop
Street, Denver, Colorado 80202-1129. The EPA requests that if at all
possible, you contact the individual listed in the FOR FURTHER
INFORMATION CONTACT section to view the hard copy of the docket. You
may view the hard copy of the docket Monday through Friday, 8:00 a.m.
to 4:00 p.m., excluding federal holidays.

FOR FURTHER INFORMATION CONTACT: Crystal Ostigaard, Air and Radiation
Division, EPA, Region 8, Mailcode 8ARD-QP, 1595 Wynkoop Street, Denver,
Colorado, 80202-1129,<PHONE_NUMBER><EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.

I. Background

    Under section 109 of the Act, the EPA has promulgated NAAQS for
certain pollutants, including PM10 (40 CFR 50.2(b)). Once
the EPA promulgates a NAAQS, section 107 of the Act specifies a process
for the designation of all areas within a state, generally as either an
attainment area (an area attaining the NAAQS) or as a NAA (an area not
attaining the NAAQS, or that contributes to nonattainment of the NAAQS
in a nearby area). For PM10, certain areas have also been
designated ``unclassifiable.'' These various designations, in turn,
trigger certain state planning requirements.
    For all areas, regardless of designation, section 110 of the Act
requires that each state adopt and submit for EPA approval a plan to
provide for implementation, maintenance and enforcement of the NAAQS.
This plan is commonly referred to as a SIP. Section 110 contains
requirements that a SIP must meet in order to be approved by the
EPA.\1\ For NAAs, SIPs must meet additional requirements contained in
part D of Title I of the Act. Usually, SIPs include measures to control
emissions of air pollutants from various sources, including stationary,
mobile and area sources. For example, a SIP may specify emission limits
at power plants or other industrial sources.
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    \1\ EPA's approval of a SIP has several consequences. For
example, after the EPA approves a SIP, the EPA and citizens may
enforce the SIP's requirements in Federal court under section 113
and section 304 of the Act; in other words, the EPA's approval of a
SIP makes the SIP ``Federally enforceable.'' Also, once the EPA has
approved a SIP, a state cannot unilaterally change the Federally
enforceable version of the SIP. Instead, the state must submit a SIP
revision for EPA review and approval.
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    Under the 1990 amendments to the CAA, Salt Lake and Utah Counties
were designated nonattainment for PM10 and classified as
Moderate areas by operation of law as of November 15, 1990 (56 FR
56694, 56840; November 6, 1991). The air quality planning requirements
for PM10 Moderate NAAs are set out in Title I, part D,
subparts 1 and 4 of the Act. As described in section 110 and 172 of the
Act, areas designated nonattainment based on a failure to meet the
PM10 NAAQS are required to develop SIPs with sufficient
control measures to expeditiously attain and maintain the NAAQS.
    On July 8, 1994, the EPA approved the PM10 SIP for Salt
Lake and Utah Counties (59 FR 35036), including approval of R307-110-
10, Section IX, Control Measures for Area and Point Sources, Part A,
Fine Particulate Matter. The SIP included a demonstration of attainment
and various control measures, including emission limits at stationary
sources. Because emissions of sulfur dioxide (SO2) and
nitrogen oxides (NOX) contribute significantly to the
PM10 problem in the area, the SIP included limits on
emissions of SO2 and NOX in addition to emissions
of PM10. Additionally, approval of R307-110-10, incorporated
by reference (IBR) the Utah SIP, Section IX, Control Measures for Area
and Point Sources, Part A, Fine Particulate Matter and made this
section a part of Utah's SIP approved rules.
    On December 6, 1999, the EPA approved revisions to the road salting
and sanding programs for the two counties (64 FR 68031). On July 1,
2002, the EPA approved a new rule, R307-310, Salt Lake County: Trading
of Emission Budgets for Transportation Conformity, to the Salt Lake
County PM10 SIP that allowed trading between PM10
and NOX motor vehicle emissions budgets (MVEBs) for
transportation conformity determinations (67 FR 44065). Additionally,
on September 2, 2008 (73 FR 51222), the EPA approved updates to R307-
310, Salt Lake County: Trading of Emission Budgets for Transportation
Conformity.
    On June 18, 2001 (66 FR 32752), the EPA approved a one-year
attainment date extension for the Salt Lake County NAA to December 31,
1995 and determined that the Salt Lake County NAA attained by this
extended attainment date. Additionally, within the June 18, 2001 (66 FR
32752) action, the EPA approved a two-year attainment date extension
for the Utah County NAA to December 31, 1996 and determined that the
Utah County NAA attained by this extended attainment date.
    On December 23, 2002, the EPA approved additional revisions to the
Utah County PM10 SIP that updated attainment demonstrations,
established new 24-hour emission limits for major stationary sources,
established new MVEBs and approved an update to R307-110-10 (67 FR
78181). On May 18, 2015 (80 FR 28193), the EPA approved a new rule,
R307-311, Utah County: Trading of Emission Budgets for Transportation
Conformity, which is the mechanism for allowing trading from MVEB of
PM10 to MVEB for NOX.
    On September 26, 1995, the EPA designated Ogden City as
nonattainment for PM10 and classified the area as Moderate
under section 107(d)(3) of the Act (60 FR 38726, July 28, 1995). On
January 7, 2013 (78 FR 885), the EPA finalized a clean data
determination (CDD) for Ogden City which suspended Utah's obligation to
make SIP submissions for attainment related requirements which includes
an attainment demonstration, reasonably available control measures
(RACM)/reasonably available control technology (RACT), reasonable
further progress (RFP), contingency measures and milestone reports.
    On October 19, 2016 (81 FR 71988), the EPA conditionally approved
revisions to R307-302, Solid Fuel Burning Devices in Box Elder, Cache,
Davis, Salt Lake, Tooele, Utah and Weber Counties based on Utah's
commitment letter dated May 19, 2016. On February 27, 2017, Utah
submitted revisions to R307-302 in accordance with that conditional
approval. When the EPA takes final action on today's proposal, it will
complete the action on the revisions described in the conditional
approval.
    On October 11, 2017 (82 FR 47149), the EPA approved revisions to
R307-

11-17 titled ``Section IX, Control Measures for Area and Point Sources,
Part H, Emission Limits'' and SIP Subsection IX. H.1-4, which
established emissions limits for PM10, NOX, and
SO2 for certain stationary sources in the NAAs.

II. The EPA's Evaluation

A. EPA's Evaluation of Utah's SIP Revisions

(i) R307-302, Solid Fuel Burning Devices in Box Elder, Cache, Davis,
Salt Lake, Tooele, Utah and Weber Counties
    The EPA conditionally approved rule revisions to R307-302--Solid
Fuel Burning Devices in Box Elder, Cache, Davis, Salt Lake, Tooele,
Utah and Weber Counties, and the rule's RACM analysis in our October
19, 2016 (81 FR 71988) final rule based on a May 19, 2016 commitment
letter from the Utah Division of Air Quality (UDAQ). Rule R307-302 is
an existing rule that was approved by the EPA on February 14, 2006 (71
FR 7679). This rule establishes emission standards for fireplaces and
solid fuel burning devices used in residential, commercial,
institutional and industrial facilities and associated outbuilding used
to provide comfort heating.
    On February 27, 2017, the State of Utah submitted revisions to
R307-302, based on the commitment letter and made additional revisions
to provide further clarification and remove redundancies within the
rule. The revisions contained in the February 27, 2017 submission
include: (1) Shortening the title of the rule to ``R307-302. Solid Fuel
Burning Devices''; (2) updating the Purpose of the rule for better
clarification; (3) updating the Definitions to include ``Seasoned wood
means wood that has a moisture content of less than or equal to 25%.'';
(4) revising the Applicability to include clarification on the solid
fuel burning device and where this rule is applicable; (5) revised
terminology throughout the rule to provide better alignment; (6)
revised to include ``Prohibited Fuels'' and additional language to
support this revision; and (7) removal of the term ``Phase 2'' in the
Prohibition section to be consistent with the 2015 New Source
Performance Standard.
    The Utah Air Quality Board proposed revisions to R307-302 for
public comment on August 3, 2016, with the public comment period held
from October 1 to October 31, 2016. UDAQ received comments from one
commenter; which included cursory questions about R307-302.\2\ UDAQ
summarizes these comments and responded within the February 1, 2017
submittal. There were no requests for a public hearing. The Utah Air
Quality Board adopted the revision to R307-302 on December 7, 2016, and
it became effective on February 1, 2017.
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    \2\ February 1, 2017 State of Utah Submittal for R307-302;
Comments and Final Adoption Memo.
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(ii) R307-110-10
    Section R307-110-10 incorporates the amendments to Section IX.A
into state rules, thereby making them effective as a matter of state
law. This is a ministerial provision and does not by itself include any
SIP measures.
(iii) R307-110-17
    Section R307-110-17 incorporates the amendments to Section IX.H
into state rules, thereby making them effective as a matter of state
law. This is a ministerial provision and does not by itself include any
control measures.
(iv) Subsection IX.H.1-2
    1. Subsection IX.H.1. General Requirements: Control Measures for
Area and Point Sources, Emission Limits and Operating Practices,
PM10 Requirements. This section establishes general
requirements for record keeping, reporting and monitoring for the
stationary sources subject to emissions limits under subsections
IX.H.2-4. Additionally, this section establishes general refinery
requirements, addressing limitations on emitting units common to the
refineries in the NAAs. These general refinery requirements include
limits at fluid catalytic cracking units, limits on refinery fuel gas,
restrictions on liquid fuel oil consumption, requirement for sulfur
removal units and requirements for hydrocarbon flares.
    Revisions that were submitted on February 15, 2019, for Subsection
IX.H.1. provided clarifications, removed implementation dates that have
passed and cleaned up other aspects of this section. These revisions
are generally non-substantive and do not affect the stringency of the
SIP; thus, the EPA is proposing to approve these revisions.
    2. Subsection IX.H.2. Source Specific Emission Limitations in Salt
Lake County PM10 Nonattainment/Maintenance Area. This
section establishes specific emission limitations for 13 sources. Major
stationary sources were identified based on their potential to emit
(PTE) of 100 tons per year (tpy) or more of PM10,
NOX, or SO2. Revisions for Subsection IX.H.2.
were submitted on February 15, 2019, and with non-substantive revisions
submitted on July 1, 2019, August 20, 2019, and October 15, 2019. A
summary of the current emission limits for retained sources, are
outlined in Table 1, below, and a summary of the proposed new emission
limits are outlined in Table 2 below. We are proposing to approve the
revisions specified in the below tables.

      Table 1--Current Source Specific Emission Limitations in the Salt Lake County PM10 Nonattainment Area
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                                                                Mass based      Concentration      Alternative
            Source              Pollutant     Process unit     limits (tpd)     based limits     emission limits
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Big West Oil Company.........  NOX........  Source-Wide.....            0.80
                               SO2........  Source-Wide.....            0.60
Chevron Products Company.....  NOX........  Source-Wide.....             2.1
                               SO2........  Source-Wide.....            1.05
Holly Refining and Marketing   NOX........  Source-Wide.....            2.09
 Company.                      SO2........  Source-Wide.....            0.31
Tesoro Refining & Marketing    NOX........  Source-Wide.....           1.988
 Company.                      SO2........  Source-Wide.....             3.1
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tpd = tons per day.

     Table 2--Proposed Source Specific Emission Limitations in the Salt Lake County PM10 Nonattainment Area
----------------------------------------------------------------------------------------------------------------
                                                                Mass based      Concentration      Alternative
            Source              Pollutant     Process Unit     limits (tpd)     based limits     emission limits
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Big West Oil Company.........  NOX........  Source-Wide.....          * 0.80  ................  195 tons per
                                                                                rolling 12-
                                                                                month period.
                               SO2........  Source-Wide.....          * 0.60  ................  140 tons per
                                                                                rolling 12-
                                                                                month period.
Chevron Products Company.....  NOX........  Source-Wide.....           * 2.1  ................  766.5 tons per
                                                                                rolling 12-
                                                                                month period.
                               SO2........  Source-Wide.....          * 1.05  ................  383.3 tons per
                                                                                rolling 12-
                                                                                month period.
                               NOX........  Rich-Burn         ..............  236 parts per
                                             Compressor                        million,
                                             Engine Number                     volumetric dry
                                             K35001.                           (ppmvd) at 0%
                                                                               O2.
                               NOX........  Rich-Burn         ..............  208 ppmvd at 0%
                                             Compressor                        O2.
                                             Engine Number
                                             K35002.
                               NOX........  Rich-Burn         ..............  230 parts per
                                             Compressor                        million dry
                                             Engine Number                     volume (ppmdv)
                                             K35003.                           at 0% O2.
Holly Refining and Marketing   NOX........  Source-Wide.....          * 2.09  ................  347.1 tons per
 Company.                                                                                rolling 12-
                                                                                month period.
                               SO2........  Source-Wide **..          * 0.31  ................  110.3 tons per
                                                                                rolling 12-
                                                                                month period.
Tesoro Refining & Marketing    NOX........  Source-Wide.....             2.3  ................  475 tons per
 Company.                                                                                rolling 12-
                                                                                month period.
                               SO2........  Source-Wide.....             3.8  ................  300 tons per
                                                                                rolling 12-
                                                                                month period.
Utah Municipal Power           NOX........  Source-Wide.....  ..............  5 ppmdv (15% O2
 Association: West Valley                                                      dry) on 30-day
 Power Plant.                                                                  rolling average.
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* These limits are not being revised.
** Excluding routine SRU turnaround maintenance emissions.

    Additional revisions within Subsection IX.H.2. include tables that
directs the owner/operator to install specified control emissions from
the equipment listed in the tables by January 1, 2019. The specific
point sources, along with the emission units and the specific control
equipment are included in Table 3, below. We are proposing to approve
the inclusion of these tables within each specified source section.

    Table 3--Proposed Source Specific Emission Units and Accompanying
                            Control Equipment
------------------------------------------------------------------------
           Source                 Emision unit        Control equipment
------------------------------------------------------------------------
Big West Oil Company........  FCCU Regenerator....  Flue gas blowback
                                                     ``Pall Filter,''
                                                     quaternary cyclones
                                                     with fabric filter.
                              H-404 #1 Crude        Ultra-low NOX
                               Heater.               burners.
                              Refinery Flares.....  Subpart Ja, and MACT
                                                     CC flaring
                                                     standards.
                              SRU.................  Tail gas incinerator
                                                     and redundant
                                                     caustic scrubber.
                              Product Loading       Vapor recovery and
                               Racks.                vapor combustors.
                              Wastewater Treatment  API separator fixed
                               System.               cover, carbon
                                                     adsorber canisters
                                                     to be installed
                                                     2019.
Chevron Products Company....  Boilers: 5, 6, 7....  Low NOX burners and
                                                     flue gas
                                                     recirculation
                                                     (FGR).
                              Cooling Water Towers  High efficiency
                                                     drift eliminators.
                              Crude Furnaces        Low NOX burners.
                               F21001, F21002.
                              Crude Oil Loading...  Vapor Combustion
                                                     Unit (VCU).
                              FCC Regenerator       Vacuum gas oil
                               Stack.                hydrotreater,
                                                     Electrostatic
                                                     precipitator (ESP)
                                                     and cyclones.
                              Flares: Flare 1, 2..  Flare gas recovery
                                                     system.
                              HDS Furnaces F64010,  Low NOX burners.
                               F64011.
                              Reformer Compressor   Selective Catalytic
                               Drivers K35001,       Reduction (SCR).
                               K35002, K35003.
                              Sulfur Recovery Unit  Tail gas treatment
                               1.                    unit and tail gas
                                                     incineration.
                              Sulfur Recovery Unit  Tail gas treatment
                               2.                    unit and tail gas
                                                     incineration.
                              Wastewater Treatment  Existing wastewater
                               Plant.                controls system of
                                                     induced air
                                                     flotation (IAF) and
                                                     regenerative
                                                     thermal oxidation
                                                     (RTO).
Holly Refining and Marketing  Process heaters and   Boilers 8 & 11:
 Company.                      boilers.              LNB+SCR
                                                    Boilers 5, 9 & 10:
                                                     SCR
                                                    Process heaters
                                                     20H2, 20H3, 23H1,
                                                     24H1, 25H1: ULNB.
                              Cooling water towers  High efficiency
                               10, 11.               drift eliminators.
                              FCCU regenerator      WGS with Lo-Tox.
                               stacks.
                              Flares..............  Flare gas recovery
                                                     system.
                              Sulfur recovery unit  Tail gas
                                                     incineration and
                                                     WGS with Lo-Tox.

                              Wastewater treatment  API separators,
                               plant.                dissolved gas
                                                     floatation (DGF),
                                                     moving bed bio-film
                                                     reactors (MBBR).
Tesoro Refining & Marketing   FCCU/CO Boiler......  Wet Gas Scrubber,
 Company.                                            LoTOx.
                              Furnace F-1.........  Ultra Low NOX
                                                     Burners.
                              Tanks...............  Tank Degassing
                                                     Controls.
                              North and South       Flare Gas Recovery.
                               Flares.
                              Furnace H-101.......  Ultra Low NOX
                                                     Burners.
                              Truck loading rack..  Vapor recovery unit.
                              Sulfur recovery unit  Tail Gas Treatment
                                                     Unit.
                              API separator.......  Floating roof
                                                     (single seal).
------------------------------------------------------------------------

    Additional revisions are found within Subsection IX.H.2.h.
Kennecott Utah Copper (KUC): Power Plant and Tailings Impoundment.
Table 4, below, provides the current emission limits and the updated
emissions limits, including for start-up/shut-down limits. We are
proposing to approve these limits and the additional start-up/shut-down
limitations found in the Natural Gas and Coal sections.

      Table 4--NOX Limits for Kennecott Utah Copper (KUC): Power Plant and Tailings Impoundment for Unit #4
----------------------------------------------------------------------------------------------------------------
                                Normal operation
       Fuel being burned        or start-up/shut-   ppmdv 3% O2       lbs/hr         lbs/MMBtu       lbs/event
                                      down
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Natural Gas...................  Normal..........              30              32            0.04  ..............
                                Start-up/Shut-    ..............  ..............  ..............             395
                                 down.
Coal..........................  Normal..........              30              32            0.04  ..............
                                Start-up/Shut-    ..............  ..............  ..............             395
                                 down.
----------------------------------------------------------------------------------------------------------------

    Other revisions are contained in Subsection IX.H.2.k.; (1)
Subsection IX.H.2.k.ii.A., where the natural gas/refinery fuel gas
combustion using: Low NOX burners (LNB): Is revised from 41
lbs/MMbtu to 0.051 lbs/MMbtu; (2) Subsection IX.H.2.k.ii.B., which
includes new language ``Stack testing is not required for natural gas/
refinery fuel gas combustion equipment with a NOX CEMS'';
(3) Subsection IX.H.2.k.iii.B., new language includes ``SRUs: The
emission rate shall be determined by multiplying the sulfur dioxide
concentration in the flue gas by the flow rate of the flue gas. The
sulfur dioxide concentration in the flue gas shall be determined by CEM
as outlined in IX.H.1.f.''; and (4) new sections are added: Subsection
IX.H.2.k.iii.C. and Subsection IX.H.2.k.iv. We are proposing approval
of these revisions.
    Other revisions are contained in Subsection IX.H.2.l.i. and ii.
where the emission point Boiler numbers were updated; Boiler #4 will be
de-commissioned, and Boiler #9 will be installed and operational by
December 31, 2019; and the initial test dates were updated for the
renumbered Boilers. Additionally, Subsection IX.H.2.l.iii. was removed
since the facility completed the requirement by the specified date of
January 1, 2019. Subsection IX.H.2.m. was updated with the new facility
name of ``Utah Municipal Power Association: West Valley Power Plant.''
We are proposing to approve these revisions.
    Additional revisions were submitted on February 15, 2019, July 1,
2019, August 20, 2019, and October 15, 2019, that included
clarifications, stack test requirements, updating specific
calculations, corrections, and non-substantive changes. We are
proposing to approve the remaining revisions within Subsection IX.H.1.
and 2. that was not specifically discussed in the tables and paragraphs
above.
(v) 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. In addition,
section 110(l) requires that each revision to an implementation plan
submitted by a state be adopted by the state after reasonable notice
and public comment.
    The Utah SIP revisions at Subsection IX.H.2 required additional
analysis to satisfy CAA 110(l) requirements due to a modification of
the source-wide caps for NOX and SO2 at the
Tesoro Refining and Marketing Company. For Tesoro, Utah increased the
allowable daily emissions caps for both NOX and
SO2 but has added a rolling 12-month cap for both
pollutants. The inclusion of a 12-month rolling cap effectively lowers
the allowable annual emissions, as outlined in Table 5 and Table 6
below. From Table 5 and Table 6, we see that while the daily emissions
cap for NOX and SO2 are slightly increased, and
the rolling allowable 12-month average emissions decreased by 250.62
tons and 831.5 tons, respectively. Monitoring data from the Salt Lake
City area for both NO2 and SO2 are shown in Table
7 below. As shown in Table 7, the current design values for
SO2 are an order of magnitude lower than their respective
standards, and the NO2 design values are 40%-50% lower than
their respective standards. Due to Salt Lake City's low NO2
and SO2 monitored values, the minimal increase in
NOX and SO2 allowable daily emissions in
combination with the overall decrease in allowable NOX and
SO2 annual emissions from the Tesoro facility will not
interfere with the areas ability to attain and maintain the
NO2 and SO2 NAAQS.

                         Table 5--Proposed Tesoro Daily and Annual Cap Revisions for NOX
----------------------------------------------------------------------------------------------------------------
                                                                                Current
                                                                 Proposed NOX    potential NOX     Proposed NOX
                  Facility                      Current NOX    daily cap (tpd)       annual           annual
                                              daily cap (tpd)                      emissions        emissions
                                                                                (tons)           (tons)
----------------------------------------------------------------------------------------------------------------
Tesoro Refining and Marketing Company.......           1.988              2.3           725.62              475
----------------------------------------------------------------------------------------------------------------

                         Table 6--Proposed Tesoro Daily and Annual Cap Revisions for SO2
----------------------------------------------------------------------------------------------------------------
                                                                                Current
                                                                 Proposed SO2    potential SO2     Proposed SO2
                  Facility                      Current SO2    daily cap (tpd)       annual           annual
                                              daily cap (tpd)                      emissions        emissions
                                                                                (tons)           (tons)
----------------------------------------------------------------------------------------------------------------
Tesoro Refining and Marketing Company.......             3.1              3.8           1131.5              300
----------------------------------------------------------------------------------------------------------------

Table 7--Salt Lake City NO2 and SO2 Monitoring Data (2016-2018) in Parts
                            per Billion (ppb)
------------------------------------------------------------------------
                                                             Monitored
           Pollutant standard               NAAQS value    design values
                                               (ppb)           (ppb)
------------------------------------------------------------------------
NO2 Annual Standard.....................              53            30.1
NO2 1-hour Standard.....................             100              53
SO2 24-hour Standard *..................             140               2
SO2 Annual Standard *...................              30               0
SO2 1-hour Standard.....................              75              7
------------------------------------------------------------------------
* The 1971 SO2 24-hour and annual standards were revoked in 2010, but
  the Salt Lake City area remains a nonattainment for the 1971 standards
  until a maintenance plan and redesignation request are submitted by
  the state and approved by the EPA.

    Within the PM10 maintenance plan, Utah used the revised
annual PTE limit when projecting the 2019, 2024, 2028 and 2030
emissions inventory.\3\ The inclusion of the PTE did not prevent the
area from demonstrating continued maintenance of the PM10
NAAQS. Similarly, Utah used the annual PTE values for the modeled
attainment demonstration of fine particulate matter (PM2.5),
submitted on February 15, 2019. With the inclusion of Tesoro's revised
limits, Utah demonstrated that the Salt Lake City PM2.5 NAA
was still able to model attainment of the PM2.5 NAAQS. We
are not acting on any aspect of the Salt Lake City PM2.5
Serious SIP within this proposed rule; the reference above is only
being used as a support to our CAA section 110(l) analysis.
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    \3\ January 4, 2016, Utah PM10 Maintenance Plans,
Technical Support Document (TSD), Chapter 3: Baseline and Projected
Inventories.
---------------------------------------------------------------------------

    The Utah SIP revisions that the EPA is proposing to approve do not
interfere with any applicable requirements of the Act, including
attainment or RFP. The DAR section R307-110-10, R307-110-17, and
Subsection IX.H.1-2, submitted on January 4, 2016, February 15, 2019,
July 1, 2019, August 20, 2019, and October 15, 2019, are intended to
strengthen the SIP. Therefore, CAA section 110(l) requirements are
satisfied.

B. What requirements must be followed for redesignation to attainment?

    In order for a NAA to be redesignated to attainment, the following
conditions in section 107(d)(3)(E) of the CAA must be met:
    (i) We must determine that the area has attained the NAAQS;
    (ii) The applicable implementation plan for the area must be fully
approved under section 110(k) of the Act;
    (iii) We must determine that the improvement in air quality is due
to permanent and enforceable reductions in emissions resulting from
implementation of the applicable implementation plan and applicable
Federal air pollutant control regulations and other permanent and
enforceable reductions;
    (iv) We must fully approve a maintenance plan for the area as
meeting the requirements of CAA section 175A; and,
    (v) The State containing such area must meet all requirements
applicable to the area under section 110 and part D of the CAA.
    Our September 4, 1992 guidance entitled ``Procedures for Processing
Requests to Redesignate Areas to Attainment'' (referred to in this
action as the Calcagni Memorandum) outlines how to assess the adequacy
of redesignation requests against the conditions listed above.
    On January 4, 2016, and on March 6, 2019, the Governor of Utah
submitted revisions to the SIP for the Salt Lake County, Utah County
and Ogden City NAAs and requested that the EPA redesignate the areas to
attainment for PM10. The following is a brief discussion of
how Utah's redesignation request and maintenance plans meet the
requirements of the Act for redesignation of the Salt Lake County, Utah
County, and Ogden City areas to attainment for PM10.

C. Do the redesignation requests and maintenance plans meet the CAA
requirements?

(i) Attainment of PM10 NAAQS
    Whether an area has attained the PM10 NAAQS is based
exclusively upon measured air quality levels over the most recent and
complete three calendar year period. See 40 CFR part 50 and 40 CFR part
50, appendix K. A state must demonstrate that an area has attained the
PM10 NAAQS through submittal of ambient air quality data
from an ambient air monitoring network representing maximum
PM10 concentrations. The data, which must be quality assured
and recorded in the EPA's Air Quality System (AQS), must show that the
average annual number of

expected exceedances for the area is less than or equal to 1.0,
pursuant to 40 CFR 50.6. In making this showing, three consecutive
years of complete air quality data must be used.
    Between 2016 and 2018, Utah operated six PM10 monitors,
which were either State and Local Air Monitoring Stations (SLAMS) or
National Air Monitoring Sites (NAMS), in the Salt Lake County, Utah
County and Ogden City NAAs. Of this total, three are in the Salt Lake
County NAA, two are in the Utah County NAA and one is in the Ogden City
NAA. As part of the redesignation request for Salt Lake County, Utah
County and Ogden City, Utah submitted ambient air quality data from the
monitoring sites which demonstrates that the area has attained the
PM10 NAAQS. This air quality data had been quality-assured
and placed in AQS on a quarterly basis. Table 8 below shows expected
exceedances for 2016-2018 for all monitors in the PM10 NAAs.

  Table 8--2015-2017 and 2016-2018 Expected PM10 Exceedances for Monitor Sites in the PM10 Nonattainment Areas
----------------------------------------------------------------------------------------------------------------
                                                                                2015-2017 24-   2016-2018 24-
                                                                                hour PM10       hour PM10
              AQS ID                     Monitor site        Nonattainment area  -------------------------------
                                                                                Average annual  Average annual
                                                                                exceedances     exceedances
----------------------------------------------------------------------------------------------------------------
49-035-1001.......................  Magna................  Salt Lake County.....           * 0.3           * 0.3
49-035-3006.......................  Hawthorn.............  Salt Lake County.....             * 0             * 0
49-035-3013.......................  Herriman.............  Salt Lake County.....           * 0.7             0.3
49-049-0002.......................  North Provo..........  Utah County..........             * 0  ..............
49-049-4001.......................  Lindon...............  Utah County..........             * 0               0
49-057-0002.......................  Ogden................  Ogden City...........           * 0.4               0
----------------------------------------------------------------------------------------------------------------
* Incomplete.\4\

    The three-year averages were either 0 or less than 1.0, which
indicates the Salt Lake County, Utah County and Ogden City areas
attained the 24-hour PM10 NAAQS. In addition, there have
been no reported exceedances of the PM10 NAAQS so far in
2019. Further information on PM10 monitoring is presented in
Subsections IX.A.11.b(1), IX.A.12.b(1), and IX.A.13.b(1) of the Salt
Lake County, Utah County and Ogden City maintenance plans,
respectively. We have evaluated the ambient air quality data and Utah
has adequately demonstrated that the PM10 NAAQS has been
attained in the Salt Lake County, Utah County and Ogden City areas.
---------------------------------------------------------------------------

    \4\ 40 CFR part 50, Appendix K specifies that ``when data for a
year are incomplete, it is necessary to compute an estimated number
of exceedances for that year by adjusting the observed number of
exceedances.'' This process is described in Appendix K, section 3.0.
While some of the quarters have missing sample days as seen in the
AQS report found in the accompanying docket, none of the quarters
where data is considered incomplete has exceedances in the same
quarter during the design value period. Additionally, the missing
data are not during an inversion period and exceedances would not be
expected. Therefore, the missing data do not affect the expected
number or exceedances in Table 8.
---------------------------------------------------------------------------

(ii) Fully Approved State Implementation Plan
    Section 107(d)(3)(E)(ii) of the CAA states that for an area to be
redesignated to attainment, it must be determined that the
Administrator has fully approved the applicable implementation plan for
the area under section 110(k).
    Those states containing initial Moderate PM10 NAAs were
required to submit a SIP by November 15, 1991, which demonstrated
attainment of the PM10 NAAQS by December 31, 1994. However,
under section 188(d) of the CAA, Moderate PM10 NAAs are
eligible for up to two one-year extensions of their attainment dates if
they meet certain requirements of the Act. On June 8, 2001 (66 FR
32752), the EPA finalized a one-year extension for the Salt Lake County
NAA and two one-year extensions for the Utah County NAA. The Salt Lake
and Utah Counties Moderate attainment date of December 31, 1994 was
extended to December 31, 1995, and December 31, 1996, respectively.
Within the June 8, 2001 (66 FR 32752) final action, the EPA also
determined that the Salt Lake and Utah Counties attained by these
extended attainment dates.
    Section 107(d)(3)(E)(ii) of the CAA states that for NAAs to be
redesignated to attainment, it must be determined that the
Administrator has fully approved the applicable implementation plan for
the areas under section 110(k). We approved the Salt Lake County and
Utah County PM10 attainment plans on July 8, 1994 (59 FR
35036). The SIP included a demonstration of attainment and various
control measures, including emission limits at stationary sources.
Because emissions of SO2 and NOX contribute
significantly to the PM10 problem in the areas, the SIPs
included limits on emissions of SO2 and NOX in
addition to emissions of PM10.
    The EPA's prior actions on Salt Lake and Utah Counties
PM10 SIPs, along with Ogden City PM10 CDD, Utah
SIP section Part H, and R307-403 are discussed in Section I: Background
above.
(iii) Improvement in Air Quality Due to Permanent and Enforceable
Measures
    Section 107(d)(3)(E)(iii) of the CAA provides that for an area to
be redesignated to attainment, the Administrator must determine that
the improvement in air quality is due to permanent and enforceable
reductions in emissions resulting from implementation of the applicable
implementation plan, implementation of applicable Federal air pollutant
control regulations, and other permanent and enforceable reductions.
    The Salt Lake County area plan was adopted in June 1991 and
approved by the EPA on July 8, 1994 (59 FR 35036). The Utah County area
plan was adopted in September 1990, modified in June 1991, and approved
by the EPA on July 8, 1994 (59 FR 35036). The Utah County area plan was
revised and adopted on June 5, 2002 and July 3, 2002, and the EPA
approved these revisions on December 23, 2002 (67 FR 78181). The SIP's
emission control plans were based on emission reductions from
stationary sources, re-entrained road dust controls, woodburning
restrictions, and mobile source emission control programs. These
permanent and enforceable control measures are explained below.
    As part of the PM10 SIP, Utah has been implementing
emission limits

found in Subsection IX.H.1-4. The titles for Subsection IX.H.1-4
include: (1) General Requirements: Control Measures for Area and Point
Sources, Emission Limits and Operating Practices, PM10
Requirements; (2) Source Specific Emission Limitations in Salt Lake
County PM10 Nonattainment/Maintenance Area; (3) Source
Specific Emission Limitations in Utah County PM10
Nonattainment/Maintenance Area; and (4) Interim Emission Limits and
Operating Practices. The revisions approved on October 11, 2017 (82 FR
47149), established emission limitations and related requirements for
certain stationary sources of PM10, NOX and
SO2, as well as updates of the inventory of major stationary
sources to accurately reflect the current sources in both the Salt Lake
County and Utah County areas.
    Utah has also implemented multiple area source rules in the Salt
Lake County, Utah County and Ogden City areas. Some area source rules
that would impact PM10 NAAs include controls on solid fuel
burning devices (R307-302), road salting/sanding (R307-307), fugitive
emissions/dust (R307-309) and aggregate processing (R307-312).\5\ On
February 25, 2016 (81 FR 9343), October 19, 2016 (81 FR 71988), and
October 2, 2019 (84 FR 52368) the EPA approved revisions to several
area source rules and approved new rules for PM2.5 NAAs into
the Utah SIP, which provide direct and indirect benefits to
PM10 NAAs.
---------------------------------------------------------------------------

    \5\ See January 4, 2016 State of Utah Submittal for
PM10 Maintenance Plans/Redesignation Requests; TSD;
Chapter 3.
---------------------------------------------------------------------------

    Additionally, on October 19, 2016 (81 FR 71988), the EPA finalized
a conditional approval of certain revisions to R307-302-5 (Solid Fuel
Burning Devices) based on a commitment letter from the director of
UDAQ. In that letter, Utah committed to ``establishing a prohibition on
fuel types that can't be burned in a solid fuel burning device at any
time.'' With UDAQ's February 27, 2017 submittal, R307-302-5 was revised
to represent what was in the commitment letter, which satisfied the
condition specified in the conditional approval. Accordingly, when the
EPA takes final action on today's proposal, it will complete the EPA's
action on the May 9, 2013, May 20, 2014, and September 8, 2015
submittals for R307-302.
    The mobile source control measures implemented in the
PM10 SIP include inspection and maintenance (I/M) programs
in Salt Lake, Utah and Weber Counties. On August 1, 2005 (70 FR 44055)
and November 2, 2005 (70 FR 66264), the EPA approved the I/M programs
for Salt Lake County and Utah County, respectively. On September 14,
2005, the EPA approved the I/M program in Weber county (70 FR 54267).
    We have evaluated the various State and Federal control measures
and historical emissions inventories and believe that the improvement
in air quality in the Salt Lake and Utah Counties NAAs have resulted
from emission reductions that are permanent and enforceable.
(iv) Fully Approved Maintenance Plan Under Section 175A of the Act
    Section 107(d)(3)(E) of the Act requires that, for a NAA to be
redesignated to attainment, we must fully approve a maintenance plan
which meets the requirements of section 175A of the Act. The plan must
demonstrate continued attainment of the relevant NAAQS in the area for
at least 10 years after our approval of the redesignation. Eight years
after our approval of a redesignation, a state must submit a revised
maintenance plan demonstrating attainment for the 10 years following
the initial 10-year period. The maintenance plan must also contain a
contingency plan to ensure prompt correction of any violation of the
NAAQS. See sections 175A(b) and (d). The Calcagni Memorandum outlines
five core elements that are necessary to ensure maintenance of the
relevant NAAQS in an area seeking redesignation from nonattainment to
attainment. Those elements, as well as guidelines for subsequent
maintenance plan revisions, are explained in detail below.
a. Attainment Inventory
    The EPA's interpretations of the CAA section 175A maintenance plan
requirements are generally provided in the General Preamble (see 57 FR
13498, April 16, 1992) and the Calcagni Memorandum referenced above.
Under our interpretations, PM10 maintenance plans should
include an attainment emission inventory to identify the level of
emissions in the area which is sufficient to maintain the NAAQS.
    An emissions inventory was developed and submitted with the
PM10 maintenance plan for the Salt Lake County, Utah County
and Ogden City areas on December 4, 2015. This submittal contains a
base year of 2011, interim-year projection inventories for 2019, 2024
and 2028, and projected maintenance inventory of 2030. The emissions
contained in the inventories include sources of PM10 and
PM10 precursor emissions located within a regional area
called a modeling domain. The modeling domain encompasses all three
areas within the state that were designated as nonattainment for
PM10: Salt Lake County, Utah County and Ogden City, as well
as a bordering region.\6\
---------------------------------------------------------------------------

    \6\ January 4, 2016 State of Utah submittal for Salt Lake
County, Utah County, and Ogden City PM10 Maintenance
Plan; Figure IX.A.11.1.
---------------------------------------------------------------------------

    Since this bordering region is so large (the modeling domain was
used for the larger region of PM2.5 nonattainment), a ``core
area'' within this domain was identified wherein a higher degree of
accuracy was included. Within this core area (which includes Weber,
Davis, Salt Lake and Utah Counties), SIP-specific inventories were
prepared to include seasonal adjustments and forecasting to represent
each of the projection years. In the bordering regions, outside the
core area, the 2011 National Emissions Inventory (NEI) was used in the
analysis. There were four general categories of sources included in
these inventories: Large stationary sources, smaller area sources, on-
road mobile sources and off-road mobile sources.
    For each of these source categories, the pollutants that were
inventoried included: PM10, SO2, NOX,
volatile organic compounds (VOC) and ammonia (NH3).
SO2 and NOX are specifically defined as
PM10 precursors, and the Community Multi-scale Air Quality
Model (CMAQ) model also considers ammonia and VOC to be contributing
factors in the formation of secondary aerosol. More detailed
descriptions of the 2011 base-year inventory and the 2019, 2024, 2028
and 2030 projection inventories can be found in section IX.A.11.c,
IX.A.12.c, and IX.A.13.c, Maintenance Plan, subsection (2) Attainment
Inventory of the Salt Lake County, Utah County, and Ogden City
Maintenance Plans, and in the technical support document (TSD). Utah's
submittal contains detailed emission inventory information that was
prepared in accordance with the EPA emission inventory guidance.\7\
Summary of emission figures from 2011 base year and the projected
inventories are provided in Table 9, 10 and 11, below.
---------------------------------------------------------------------------

    \7\ EPA's current guidance on the preparation of PM10
emission inventories includes, ``PM10 Emission Inventory
Requirements,'' September 1994, ``Emission Inventory Improvement
Program Technical Report Serious, Volumes I-VII,'' July 1997 and
September 1999, ``Revised 1999 National Emission Inventory
Preparation Plan,'' February 2001, ``Emissions Inventory Guidance
for Implementation of Ozone and Particulate Matter National Ambient
Air Quality Standards (NAAQS) and Regional Haze Regulations'', May
2017 .

                    Table 9--Salt Lake County NAA; Actual Emissions From 2011 and Emission Projections for 2019, 2024, 2028, and 2030
                                                                  [Tons per day (tpd)]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                   Year                            Source category             PM10             SO2             NOX             VOC             NH3
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011 Baseline.............................  Area Sources................            5.50            0.37            9.14           30.35            3.82
                                            Non-Road....................            7.12            0.32           11.71            6.38            0.00
                                            Point Sources...............            4.04            8.90           15.56            2.97            0.20
                                            Mobile Sources..............           10.95            0.28           57.96           35.35            1.14
                                                                         -------------------------------------------------------------------------------
                                               2011 Total...............           27.61            9.87           94.37           75.05            5.16
--------------------------------------------------------------------------------------------------------------------------------------------------------
2019......................................  Area Sources................            4.88            0.35            5.84           22.06            4.18
                                            Non-Road....................            8.28            0.36            9.11            5.94            0.01
                                            Point Sources...............           11.29            7.72           22.17            3.77            0.26
                                            Mobile Sources..............           10.88            0.31           25.79           21.16            0.89
                                                                         -------------------------------------------------------------------------------
                                               2019 Total...............           35.33            8.74           62.91           52.93            5.34
--------------------------------------------------------------------------------------------------------------------------------------------------------
2024......................................  Area Sources................            5.03            0.51            5.41           22.83            4.48
                                            Non-Road....................            8.83            0.40            8.48            6.22            0.01
                                            Point Sources...............           11.52            8.16           22.36            3.86            0.29
                                            Mobile Sources..............           11.28            0.29           17.16           16.63            0.89
                                                                         -------------------------------------------------------------------------------
                                               2024 Total...............           36.66            9.36           53.41           49.54            5.67
--------------------------------------------------------------------------------------------------------------------------------------------------------
2028......................................  Area Sources................            5.25            0.43            5.58           23.80            4.67
                                            Non-Road....................            9.27            0.44            8.43            6.54            0.01
                                            Point Sources...............           11.72            8.57           22.55            3.95            0.31
                                            Mobile Sources..............           11.82            0.28           13.88           13.94            0.91
                                                                         -------------------------------------------------------------------------------
                                               2028 Total...............           38.06            9.72           50.44           48.23            5.90
--------------------------------------------------------------------------------------------------------------------------------------------------------
2030......................................  Area Sources................            5.36            0.34            5.63           24.30            4.76
                                            Non-Road....................            9.52            0.46            8.50            6.72            0.01
                                            Point Sources...............           11.83            8.82           22.68            4.00            0.32
                                            Mobile Sources..............           12.07            0.28           12.59           13.34            0.93
                                                                         -------------------------------------------------------------------------------
                                               2030 Total...............           38.78            9.90           49.40           48.36            6.02
--------------------------------------------------------------------------------------------------------------------------------------------------------

                      Table 10--Utah County NAA; Actual Emissions From 2011 and Emission Projections for 2019, 2024, 2028, and 2030
                                                                          [tpd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                   Year                            Source category             PM10             SO2             NOX             VOC             NH3
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011 Baseline.............................  Area Sources................            3.90            0.28            5.61           13.02            6.62
                                            Non-Road....................            3.53            0.02            4.24            2.31            0.00
                                            Point Sources...............            0.28            0.29            1.03            0.18            0.18
                                            Mobile Sources..............            4.90            0.13           24.64           11.89            0.49
                                                                         -------------------------------------------------------------------------------
                                               2030 Total...............           12.61            0.72           35.52           27.40            7.29
--------------------------------------------------------------------------------------------------------------------------------------------------------
2019......................................  Area Sources................            3.79            0.29            2.15           10.68            6.47
                                            Non-Road....................            4.80            0.02            3.04            1.95            0.01
                                            Point Sources...............            0.87            0.44            3.24            0.86            0.43
                                            Mobile Sources..............            6.04            0.17           13.77            6.43            0.46
                                                                         -------------------------------------------------------------------------------
                                               2019 Total...............           15.50            0.92           22.20           19.92            7.37
--------------------------------------------------------------------------------------------------------------------------------------------------------
2024......................................  Area Sources................            2.83            0.35            1.80           11.66            5.98
                                            Non-Road....................            5.19            0.02            2.45            1.90            0.01
                                            Point Sources...............            0.92            0.47            3.42            0.91            0.43
                                            Mobile Sources..............            6.37            0.16            9.01            5.22            0.48
                                                                         -------------------------------------------------------------------------------
                                               2024 Total...............           15.31            1.00           16.68           19.69            6.90
--------------------------------------------------------------------------------------------------------------------------------------------------------
2028......................................  Area Sources................            3.06            0.27            1.81           12.49            5.92
                                            Non-Road....................            5.68            0.02            2.17            1.92            0.01
                                            Point Sources...............            0.96            0.49            3.58            0.96            0.43
                                            Mobile Sources..............            6.97            0.16            7.28            4.60            0.51
                                                                         -------------------------------------------------------------------------------
                                               2028 Total...............           16.67            0.94           14.84           19.97            6.87
--------------------------------------------------------------------------------------------------------------------------------------------------------

2030......................................  Area Sources................            3.17            0.18            1.78           12.90            5.89
                                            Non-Road....................            6.25            0.02            2.07            1.94            0.01
                                            Point Sources...............            0.99            0.49            3.67            0.98            0.43
                                            Mobile Sources..............            7.66            0.16            6.81            4.54            0.54
                                           -------------------------------------------------------------------------------------------------------------
                                               2030 Total...............           18.07            0.85           14.33           20.36            6.87
--------------------------------------------------------------------------------------------------------------------------------------------------------

                      Table 11--Ogden City NAA; Actual Emissions From 2011 and Emission Projections for 2019, 2024, 2028, and 2030
                                                                          [tpd]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                   Year                            Source category             PM10             SO2             NOX             VOC             NH3
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011 Baseline.............................  Area Sources................            0.85            0.08            2.12            5.67            0.86
                                            Non-Road....................            0.90            0.00            1.32            0.91            0.00
                                            Point Sources...............            0.00            0.00            0.00            0.00            0.00
                                            Mobile Sources..............            2.09            0.05           12.18            8.58            0.22
                                           -------------------------------------------------------------------------------------------------------------
                                            2011 Total..................            3.84            0.13           15.62           15.16            1.08
--------------------------------------------------------------------------------------------------------------------------------------------------------
2019......................................  Area Sources................            0.61            0.08            1.21            3.87            0.88
                                            Non-Road....................            1.00            0.00            0.84            0.77            0.00
                                            Point Sources...............            0.00            0.00            0.00            0.00            0.00
                                            Mobile Sources..............            2.07            0.06            6.68            5.26            0.17
                                           -------------------------------------------------------------------------------------------------------------
                                               2019 Total...............            3.68            0.14            8.73            9.90            1.05
--------------------------------------------------------------------------------------------------------------------------------------------------------
2024......................................  Area Sources................            0.65            0.12            1.16            4.18            0.95
                                            Non-Road....................            1.05            0.00            0.70            0.77            0.00
                                            Point Sources...............            0.00            0.00            0.00            0.00            0.00
                                            Mobile Sources..............            2.11            0.06            4.50            4.19            0.17
                                           -------------------------------------------------------------------------------------------------------------
                                               Total....................            3.81            0.18            6.36            9.14            1.12
--------------------------------------------------------------------------------------------------------------------------------------------------------
2028......................................  Area Sources................            0.71            0.10            1.21            4.38            0.99
                                            Non-Road....................            1.13            0.00            0.66            0.78            0.00
                                            Point Sources...............            0.00            0.00            0.00            0.00            0.00
                                            Mobile Sources..............            2.17            0.05            3.12            3.42            0.17
                                           -------------------------------------------------------------------------------------------------------------
                                               2028 Total...............            4.01            0.15            4.99            8.58            1.16
--------------------------------------------------------------------------------------------------------------------------------------------------------
2030......................................  Area Sources................            0.71            0.08            1.21            4.50            0.99
                                            Non-Road....................            1.17            0.00            0.64            0.80            0.00
                                            Point Sources...............            0.00            0.00            0.00            0.00            0.00
                                            Mobile Sources..............            2.22            0.05            2.83            3.26            0.17
                                           -------------------------------------------------------------------------------------------------------------
                                               2030 Total...............            4.10            0.13            4.68            8.56            1.16
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Following our review, we have determined that Utah prepared an
adequate attainment inventory for the Salt Lake County, Utah County and
Ogden City areas.
b. Maintenance Demonstration
    The Calcagni Memorandum states that where modeling was relied on to
demonstrate maintenance, the plan should contain a summary of the air
quality concentrations expected to result from the application of the
control strategies. Also, the plan should identify and describe the
dispersion model or other air quality model used to project ambient
concentrations. The maintenance demonstrations for the Salt Lake
County, Utah County and Ogden City areas used a regional photochemical
model.
    Prior to the development of the PM10 maintenance plans,
UDAQ conducted a technical analysis to support the development of
Utah's 24-hour SIP for PM2.5. That analysis included
preparation of emissions inventories and meteorological data, and the
evaluation and application of a regional photochemical model. Outside
of the springtime high wind events and wildfires, the Wasatch Front
experiences high 24-hour PM10 concentrations under stable
meteorological conditions in the winter during cold air pool
temperature inversions. These are the same episodes where the Wasatch
Front sees its highest concentrations of PM2.5 that
sometimes exceed the 24-hour PM2.5 NAAQS. Most (60% to 90%)
of the PM10 observed during high wintertime pollution days
consists of PM2.5. The dominant species of the wintertime
PM10 is secondarily formed particulate nitrate, which is
also the dominant species of PM2.5. Given these
similarities, the PM2.5 modeling analysis was utilized as
the foundation for the PM10 maintenance plans.

    The CMAQ model performance evaluation for the PM10
maintenance plans builds on the detailed model performance evaluation
that was part of the UDAQ's previous PM2.5 SIP process. UDAQ
used the same modeling episode that was used in the PM2.5
SIP, which is the 45-day modeling episode from the winter of 2009-2010.
The modeled meteorological datasets from the Weather Research and
Forecasting (WRF) model for the PM10 Plans are the same
datasets used for the PM2.5 SIP. Also, the CMAQ version
(4.7.1) and CMAQ model setup for the PM10 modeling matches
the PM2.5 SIP setup.
    For these reasons, much of the information presented in the
PM10 maintenance plans pertains specifically to the
PM2.5 evaluation. The information was supplemented with
information pertaining to PM10, most notably with respect to
the PM10 model performance evaluation.
    For PM10, the CMAQ model performance was acceptable at
all locations in northern Utah. CMAQ was able to reproduce the multiday
buildup and washout of the pollution episodes during the 2009-2010
winter and was able to reproduce the peak PM10
concentrations during most of the other two episodes modeled, January
11-20, 2007, and February 14-18, 2008. However, the model simulation
for the 2010 January 8-14 episode failed to build to the high
PM10 concentration (>80 micrograms per cubic meter
([micro]g/m\3\)) observed at the monitors. This episode featured an
``early model washout,'' which had similar results for
PM2.5.
    After determining that the model had acceptable performance for the
2009-2010 inversion episodes, the model was utilized to make future-
year attainment projections. The first step in projecting future
PM10 concentrations is to quantify current pollution levels
which are expressed as a Baseline Design Value (BDV). The BDV is
consistent with the form of the 24-hour PM10 NAAQS where the
probability of exceeding the standard should be no greater than once
per calendar year. Thus, the BDV is calculated as the 3-year average of
second highest measured 24-hour average PM10 concentration
each year. Table 12 below, provides the BDV for the five monitors that
span the three NAAs: Salt Lake County, Utah County and Ogden City.
These values were calculated based on data collected during the 2011-
2014 time-period.

    Table 12--Baseline Design Value for Each Monitor in the PM10 NAAs
                             ([micro]g/m\3\)
------------------------------------------------------------------------
              Site                       PM10 NAA          2011-2014 BDV
------------------------------------------------------------------------
Ogden..........................  Ogden City.............            88.2
Hawthorne......................  Salt Lake County.......           100.9
Magna..........................  Salt Lake County.......            70.5
Lindon.........................  Utah County............           111.4
North Provo....................  Utah County............           124.4
------------------------------------------------------------------------

    For each future year, an attainment projection is made by
calculating a concentration termed the Future Design Value (FDV). This
calculation is made for each monitor included in the analysis, and then
compared to the NAAQS (150 [micro]g/m\3\). When the FDV is smaller than
the NAAQS at every monitor in the NAA, this would demonstrate
attainment for the area in that specific future year. In making future-
year projections, the output from the CMAQ model is not considered the
final answer; rather the model is used in a relative sense. In doing
this, a comparison is made using the predicted concentrations for both
the year in question and a pre-selected base-year, which is 2011. This
comparison results in a Relative Response Factor (RRF) which is
calculated as the ratio of the model predicted PM10
concentration in the future year to the modeled PM10
concentration in the 2011 base year. Finally, the FDV is calculated by
multiplying the BDV with the RRF. Additional discussions pertaining to
the RRF can be found in the maintenance plans for the three NAAs: Salt
Lake County, Utah County and Ogden City. The FDV's are compared to the
NAAQs in order to determine whether attainment is predicted at each
monitoring location. An RRF greater than one indicates the model
predicted PM10 is greater in the future year than in the
2011 base year, and typically is a result of increased emissions in the
future year associated with projected population growth. Table 13 below
provides FDV results for each monitor and projection year and shows
that no FDV exceeds the NAAQS. Therefore, continued attainment is
demonstrated in all three NAAs.

           Table 13--Baseline Design Values, Relative Response Factors, and Future Design Values for all Monitors and Future Projection Years
                                        [Units of design values are [micro]g/m\3\, while RRF's are dimensionless]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                   Monitor                     2011  BDV   2019  RRF   2019  FDV   2024  RRF   2024  FDV   2028  RRF   2028  FDV   2030  RRF   2030  FDV
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ogden.......................................        88.2        1.05        92.6        1.04        91.7        1.04        91.7        1.05        92.6
Hawthorne...................................       100.9        1.09       110.0        1.09       110.0        1.11         112        1.12       113.0
Magna.......................................        70.5        1.14        80.4        1.13        79.7        1.14        80.4        1.15        81.1
Lindon......................................       111.4        1.16       129.2        1.12        12.8        1.14       127.0        1.16       129.2
North Provo.................................       124.4        1.15       143.1        1.12       139.3        1.13       140.6        1.15       143.1
--------------------------------------------------------------------------------------------------------------------------------------------------------

    According to the Calcagni Memorandum, any assumptions concerning
emission rates must reflect permanent, enforceable measures. A state
cannot take credit in the maintenance demonstration for reductions
unless there are regulations in place requiring those reductions or the
reductions are otherwise shown to be permanent. States are expected to
maintain implemented control strategies despite redesignation to
attainment,

unless such measures that achieve equivalent reductions. Emission
reductions from source shutdowns can be considered permanent and
enforceable to the extent that those shutdowns have been reflected in
the SIP and all applicable permits have been modified accordingly.
    In preparing the Salt Lake County, Utah County and Ogden City
maintenance plans, Utah made revisions to their control strategies
found in Section IX.H.1, 2, 3 and 4. These revisions were approved by
the EPA on October 11, 2017 (82 FR 47149). Additionally, on February
15, 2019, and with non-substantive changes submitted on July 1, 2019,
August 20, 2019, and on October 15, 2019, the State of Utah submitted
revisions to Section IX.H.1-2. We are acting on these revisions within
this action and our analysis of the revisions are discussed above in
section II.A of this proposed rule.
    As discussed above in section II.C.iii. of this proposed rule, Utah
has also implemented multiple area source rules in the Salt Lake
County, Utah County and Ogden City areas. Some area source rules that
would impact PM10 NAAs include controls on solid fuel
burning devices, road salting/sanding, fugitive emissions/dust, and
aggregate processing. On February 25, 2016 (81 FR 9343), October 19,
2016 (81 FR 71988) and October 2, 2019 (84 FR 52368) the EPA acted on
area source rules for PM2.5 NAAs which would provide direct
and indirect benefits to PM10 NAAs. As discussed above, we
are also acting on revisions to the state's solid fuel burning devices
rule within this action.
    The EPA believes Utah has adequately demonstrated that the Salt
Lake County, Utah County and Ogden City areas will maintain the
PM10 NAAQS to 2030.
c. Monitoring Network
    Once a NAA has been redesignated to attainment, the state must
continue to operate an appropriate air quality monitoring network, in
accordance with 40 CFR part 58, to verify the attainment status of the
area. The maintenance plans should contain provisions for continued
operation of air quality monitors that will provide such verification.
We approve these monitoring sites annually, and any future change would
require discussion and approval from the EPA. In its January 4, 2016
submittal, Utah commits to maintaining an ambient monitoring network
for PM10 in Salt Lake County, Utah County and Ogden City, in
accordance with 40 CFR part 58 and the Utah SIP.
d. Verification of Continued Attainment
    Utah's maintenance plan submittal for Salt Lake County, Utah County
and Ogden City, indicates how the State will track the progress of the
maintenance plans. This is necessary due to the fact that the emissions
projections made for the maintenance demonstrations depend on
assumptions of point and area source growth. In Sections IX.A.11.c.(9),
IX.A.12.c.(9) and IX.A.13.c.(9), Utah commits to track and document
measured mobile source parameters (e.g., vehicle miles traveled,
congestion, fleet mix, etc.) and changes in new and modified stationary
source permits. If these and the resulting emissions change
significantly over time, the State will perform appropriate studies to
determine: (1) Whether additional and/or re-sited monitors are
necessary and (2) whether mobile and stationary source emission
projections are on target.
e. Contingency Plan
    Section 175A(d) of the Act requires that a maintenance plan also
include contingency provisions, as necessary, to promptly correct any
violation of the NAAQS that occurs after redesignation of the area. For
the purposes of section 175A, the state is not required to have fully
adopted contingency measures that will take effect without further
action by the state in order for the maintenance plan to be approved.
However, the contingency plan is an enforceable part of the SIP and
should ensure that contingency measures are adopted expeditiously once
they are triggered. The plan should discuss the measures to be adopted
and a schedule and procedure for adoption and implementation. The
contingency plan must require that the state will implement all
measures contained in the Part D nonattainment plan for the area prior
to redesignation. The state should also identify the specific
indicators, or triggers, which will be used to determine when the
contingency plan will be implemented.
    As stated in Sections IX.A.11.c.(10), IX.A.12.c.(10), and
IX.A.13.c.(10) of the Salt Lake County, Utah County and Ogden City
maintenance plans, triggering the contingency plan does not
automatically require a revision to the SIP, nor does it necessarily
mean the area will be redesignated once again to nonattainment.
Instead, the State will normally have an appropriate timeframe to
correct the potential violation with implementation of one or more
adopted contingency measures. In the event that violations continue to
occur, additional contingency measures will be adopted until the
violations are corrected.
    Upon notification of a potential violation of the PM10
NAAQS, the State will develop appropriate contingency measures 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 exceedances, and the
most recent estimates of growth and emissions will be reviewed. The
possibility that an exceptional event occurred will also be evaluated.
    Upon monitoring a potential violation of the PM10 NAAQS,
including exceedances flagged as exceptional events but not concurred
with by the EPA, the State will take the following actions: (1) The
State will identify the source(s) of PM10 causing the
potential violation, and report the situation to EPA Region 8 within
four months of the potential violation; and (2) The State will identify
a means of corrective action within six months after a potential
violation.
    The Salt Lake County maintenance plan list of contingency measures
includes: (1) Re-evaluate the thresholds at which a red or yellow burn
day is triggered, as established in R307-302; and (2) Further controls
on stationary sources to include the controls previously approved into
the PM10 SIP by the EPA (effective August 8, 1994). The
sources are listed in Section IX.A.11.c.(10)(b).
    The Utah County maintenance plan list of contingency measures
includes: (1) Re-evaluate the thresholds at which a red or yellow burn
day is triggered, as established in R307-302; and (2) Further controls
on stationary sources.
    The Ogden City maintenance plan list of contingency measures
includes: (1) Re-evaluate the thresholds at which red or yellow burn
day is triggered, as established in R307-302; and (2) Expand the road
salting and sanding program in R307-307 to include Weber County.
    The State will then hold a public hearing to consider the
contingency measures identified to address the potential violation. The
State will require implementation of such corrective action no later
than one year after a violation is confirmed. Any contingency measure
adopted and implemented will become part of the next revised
maintenance plan submitted to the EPA for approval.
    Based on the above, we find that the contingency measures provided
in the Salt Lake County, Utah County and Ogden City PM10
maintenance plans are

sufficient and meet the requirements of section 175A(d) of the CAA.
f. Subsequent Maintenance Plan Revisions
    In accordance with section 175A(b) of the Act, Utah is required to
submit a revision to the maintenance plans eight years after the
redesignation of the Salt Lake County, Utah County and Ogden City areas
to attainment for PM10. This revision is to provide for
maintenance of the NAAQS for an additional ten years following the
first ten-year period. In the Salt Lake County, Utah County and Ogden
City maintenance plans, Utah committed to submit a revised maintenance
plan eight years after the approval of the redesignation request and
maintenance plan.
(v) Meeting Applicable Requirements of Section 110 and Part D of the
Act
    In order for an area to be redesignated to attainment, section
107(d)(3)(E) requires that it must have met all applicable requirements
of section 110 and part D of the Act. We interpret this to mean that,
for a redesignation request to be approved, the State must have met all
requirements that applied to the subject area prior to, or at the time
of, submitting a complete redesignation request. In our evaluation of a
redesignation request, we do not need to consider other requirements of
the CAA that became due after the date of the submission of a complete
redesignation request.
a. Section 110 Requirements
    Section 110(a)(2) contains general requirements for nonattainment
plans. For purposes of redesignation, the Utah SIP was reviewed to
ensure that all applicable requirements under the amended Act were
satisfied. These requirements were met with Utah's November 15, 1991,
February 1, 1995, May 13, 2002, and July 3, 2002 submittals for the
Salt Lake County and Utah County PM10 NAAs. We approved
these submittals on July 8, 1994 (59 FR 35036), December 6, 1999 (64 FR
68031), July 1, 2002 (67 FR 44065), and December 23, 2002 (67 FR
78181). Ogden City PM10 NAA satisfied section 110(a)(2) when
the EPA finalized a CDD on January 7, 2013 (78 FR 885).
b. Part D Requirements
    Before a PM10 NAA may be redesignated to attainment, the
state must have fulfilled the applicable requirements of part D.
Subpart 1 of part D establishes the general requirements applicable to
all NAAs, while subpart 4 of part D establishes specific requirements
applicable to PM10 NAAs. The General Preamble (see 57 FR
13530, et seq.) provides that the applicable requirements of CAA
section 172 are 172(c)(3) (emissions inventory), 172(c)(5) (new source
review permitting program), 172(c)(7) (the section 110(a)(2) air
quality monitoring requirements), and 172(c)(9) (contingency measures).
It is also worth noting that we interpreted the requirements of section
172(c)(2) (RFP) and 172(c)(6) (other measures) as being irrelevant to a
redesignation request because they only have meaning for an area that
is not attaining the standard. See Calcagni Memorandum and the General
Preamble, 57 FR at 13564, dated April 16, 1992. Finally, the State has
not sought to exercise the options that would trigger sections
172(c)(8) (equivalent techniques). Thus, these provisions are also not
relevant to this redesignation request.
    The requirements of section 172(c) and 189(a) regarding attainment
of the PM10 NAAQS, and the requirements of section 172(c)
regarding RFP, imposition of RACM, the adoption of contingency
measures, and the submission of an emission inventory, have been
satisfied through our July 8, 1994 (59 FR 35036), December 6, 1999 (64
FR 68031), June 8, 2001 (66 FR 32752), July 1, 2002 (67 FR 44065),
December 23, 2002 (67 FR 78181), February 25, 2016 (81 FR 9343),
October 19, 2016 (81 FR 71988), October 11, 2017 (82 FR 47149) and
October 2, 2019 (84 FR 52368) approvals of the Salt Lake County and
Utah County PM10 SIPs and the demonstration that the area is
attaining the NAAQS. These requirements for the Ogden City
PM10 NAA were satisfied with our January 7, 2013 (78 FR 885)
CDD which suspended Utah's obligation to make a SIP submission for
attainment related requirements which includes: An attainment
demonstration, RACM/RACT, RFP, contingency measures, and milestone
reports. With this action we will satisfy Utah's obligation to submit
an emissions inventory for the Ogden City PM10 NAA.
Additionally, the Ogden City PM10 NAA attained by the
Moderate PM10 attainment date of December 31, 2000.\8\ The
expected exceedances for 1998-2000 was 0.\9\
---------------------------------------------------------------------------

    \8\ July 28, 1995 Direct Final Rule; Designation of Area for Air
Quality Planning Purposes, Utah, Designation of Ogden City
PM10 Nonattainment Area.
    \9\ 1998-2000 Expected Exceedances AQS Report.
---------------------------------------------------------------------------

    We approved the requirements of the part D new source review permit
program for Utah on July 25, 2019 (84 FR 35831). Once the Salt Lake
County, Utah County and Ogden City areas are redesignated to
attainment, the prevention of significant deterioration (PSD)
requirements of part C of the Act will apply. We must ensure that the
State has made any needed modifications to its PSD regulations so that
Utah's PSD regulations will apply in the Salt Lake County, Utah County
and Ogden City areas after redesignation. Utah's PSD regulations, R307-
405 Permits: Major Sources in Attainment or Unclassified Areas (PSD),
which we approved as meeting all applicable Federal requirements on
July 15, 2011 (76 FR 41712) and January 29, 2016 (81 FR 4957), apply to
any area designated unclassifiable or attainment and, thus, will become
fully effective in the Salt Lake County, Utah County and Ogden City
areas upon redesignation of the areas to attainment.

D. Have the transportation conformity requirements been met?

    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 (sections 93.100 to
93.129) 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
EPA's conformity rule typically requires a demonstration that emissions
from the Regional Transportation Plan (RTP), as applicable, and the
Transportation Improvement Program (TIP) are consistent with the 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 usually
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
areas.
    According to 40 CFR 93.118(b)(2), when a maintenance plan has been
submitted, mobile source emissions from an RTP or TIP must be less than
or equal to the MVEB established for the last year of the maintenance
plan, and for any other years for which the maintenance plan
establishes MVEBs. If the maintenance plan does not establish MVEBs for
any years other than the last year of the maintenance plan, the
demonstration of consistency with the MVEBs must be accompanied by a

qualitative finding that there are no factors which would cause or
contribute to a new violation or exacerbate an existing violation in
the years before the last year of the maintenance plan. For analysis
years after the last year of the maintenance plan, emissions must be
less than or equal to the MVEBs established for the last year of the
maintenance plan. In addition, we note that if an EPA-approved NAA
control strategy implementation plan has established MVEBs for years in
the timeframe of the transportation plan, then mobile source emissions
in these years must be less than or equal to the NAA's control strategy
implementation plan's MVEBs for these years.
    With respect to previously established MVEBs, we note for the Salt
Lake County nonattainment plan, Utah had previously adopted MVEBs for
2003. These budgets were 40.3 tons per day of primary PM10
and 32.3 tons per day of NOX. These budgets were derived by
the Wasatch Front Regional Council (WFRC), a local Metropolitan
Planning Organization (MPO) for the Salt Lake City and Ogden urban
areas, in conjunction with the EPA, by using the Salt Lake County
PM10 SIP element attainment year (2003) emission inventories
and adjusted for winter weekday vehicle miles traveled (VMT) rates. The
above noted PM10 and NOX MVEBs have continued to
apply for the WFRC's RTP and TIP conformity determinations since 2003.
    In the Utah County nonattainment plan, the State had previously
adopted MVEBs for 2003 and two future horizon years which were used in
transportation planning, 2010 and 2020. On December 23, 2002 (67 FR
78181), the EPA approved the Utah County MVEBs as presented in Table 14
below.

    Table 14--Historical Utah County Transportation Conformity MVEBs
------------------------------------------------------------------------
                                           Primary PM10
                  Year                      (tons/day)      NOX  (tons/
                                                               day)
------------------------------------------------------------------------
2003....................................            6.57           20.35
2010....................................            7.74           12.75
2020....................................           10.34            5.12
------------------------------------------------------------------------

    In addition to the above On July 1, 2002 (67 FR 44065) the EPA
approved the State's rule R307-310 for Salt Lake County: ``Trading of
Emission Budgets for Transportation Conformity.'' R307-310 allows
trading between the PM10 and NOX MVEBs for
purposes of demonstrating transportation conformity by the WFRC.
Similarly, on May 18, 2015 (80 FR 28193), the EPA approved the State's
rule R307-311 for Utah County: ``Trading of Emission Budgets for
Transportation Conformity.'' R307-311 also allows trading between the
PM10 and NOX MVEBs for purposes of demonstrating
transportation conformity by the Mountainland Association of
Governments (MAG) who is the MPO for Utah County.
    For the Ogden City PM10 NAA, we designated Ogden City as
nonattainment on July 28, 1995 (60 FR 38726). Using our CDD approach,
on July 30, 2012, the EPA proposed to determine that the Ogden City NAA
was currently attaining the 24-hour NAAQS for PM10, based on
certified, quality assured data for the years 2009 through 2011, and
that Utah's obligation to submit certain CAA requirements would be
suspended for so long as the area continued to attain the
PM10 NAAQS (77 FR 44544). We finalized our proposal with our
final rule dated January 7, 2013 (78 FR 885). PM10 NAAs like
Ogden City, that have an approved CDD, are required to use the interim
emissions test, described in 40 CFR 93.119, to demonstrate conformity
(see 40 CFR 93.109(c)(5) and (6)). As applicable, the WFRC, which is
the applicable MPO for Ogden City, has been performing conformity
determinations for the Ogden City PM10 NAA using the 40 CFR
93.119 interim emissions test. The WFRC demonstrates that RTP and TIP
conformity determinations show that projected future year
PM10 and NOX emissions will be at or below the
established and updated 1990 level of PM10 and
NOX emissions.
    For the Ogden City, Salt Lake County and Utah County maintenance
plans, the State is establishing transportation conformity MVEBs for
direct PM10 and NOX for 2030. The derivation of
these 2030 MVEBs is provided as follows:
a. Ogden City
    The Ogden City maintenance area and the corresponding 2030 MVEBs
are presented in Table 15 below:

  Table 15--Ogden City Maintenance Area Transportation Conformity 2030
                                  MVEBs
------------------------------------------------------------------------
   2030 PM10 MVEB  (tons per day)       2030 NOX MVEB  (tons per day)
------------------------------------------------------------------------
                       1.50                                 1.00
------------------------------------------------------------------------

    We note that the originally modeled 2030 maintenance year had
mobile sources emissions levels of 0.71 tons per winter-weekday of
direct PM10 and 0.70 tons per winter-weekday of
NOX. These levels of 2030 mobile sources direct
PM10 and NOX would typically become the MVEBs for
2030. However, our conformity rule does allow the implementation plan
to quantify explicitly the amount by which motor vehicle emissions
could be higher while still demonstrating compliance with the
maintenance requirement (see 40 CFR 93.124(a)). These additional
emissions that can be allocated to the applicable MVEB are considered
the ``safety margin.'' As defined in 40 CFR 93.101, safety margin
represents the amount of emissions by which the total projected
emissions from all sources of a given pollutant are less than the total
emissions that would satisfy the applicable requirement for
demonstrating maintenance. The implementation plan can then allocate
some or all of this ``safety margin'' to the applicable MVEBs for
transportation conformity purposes. The State performed additional
modeling for 2030 and established that the PM10 and
NOX mobile source emissions could be increased to arrive at
those MVEB figures presented in Table 15 above.
b. Salt Lake County
    The Salt Lake County maintenance area and the corresponding 2030
MVEBs are presented in Table 16 below:

  Table 16--Salt Lake County Maintenance Area Transportation Conformity
                               2030 MVEBs
------------------------------------------------------------------------
   2030 PM10 MVEB  (tons per day)       2030 NOX MVEB  (tons per day)
------------------------------------------------------------------------
                      24.00                                21.00
------------------------------------------------------------------------

    We note that the originally modeled 2030 maintenance year had
mobile sources emissions levels of 12.07 tons per winter-weekday of
direct PM10 and 12.59 tons per winter-weekday of
NOX. These levels of 2030 mobile sources direct
PM10 and NOX would typically become the MVEBs for
2030. As with the Ogden City maintenance area noted above, the State
elected to also use the above described safety margin modeling
procedure to arrive at the applicable 2030 MVEBs for the Salt Lake
County maintenance area. As such, the State performed additional
modeling for 2030 and established that the PM10 and
NOX mobile source emissions could be increased to arrive at
those MVEB figures presented in Table 16 above.
c. Utah County
    The Utah County maintenance area and the corresponding 2030 MVEBs
are presented in Table 17 below:

  Table 17--Utah County Maintenance Area Transportation Conformity 2030
                                  MVEBs
------------------------------------------------------------------------
   2030 PM10 MVEB  (tons per day)       2030 NOX MVEB  (tons per day)
------------------------------------------------------------------------
                      12.28                                 8.34
------------------------------------------------------------------------

    We note that the originally modeled 2030 maintenance year had
mobile sources emissions levels of 7.66 tons per winter-weekday of
direct PM10 and 6.81 tons per winter-weekday of
NOX. These levels of 2030 mobile sources direct
PM10 and NOX would typically become the MVEBs for
2030. As with the Ogden City maintenance area noted above, the State
elected to also use the above described safety margin modeling
procedure to arrive at the applicable 2030 MVEBs for the Utah County
maintenance area. As such, the State performed additional modeling for
2030 and established that the PM10 and NOX mobile
source emissions could be increased to arrive at those MVEB figures
presented in Table 17 above.
    During the development of the Salt Lake County and Utah County
PM10 maintenance plans, the EPA became aware of a potential
inconsistency regarding the VMT being used. The MAG and WFRC MPOs
initially used elevated 2030 VMT numbers, for the development of the
Salt Lake County and Utah County PM10 SIP maintenance plans,
that exceeded the actual MPO's own projected VMT numbers for 2030. Our
understanding was the MPOs intention was to secure sufficient
PM10 and NOX 2030 MVEBs, for RTP/TIP
transportation conformity determinations, that would take into
consideration the rate of brisk growth within Utah and to also protect
air quality for the duration of the respective PM10
maintenance plan. The UDAQ advised that as demonstrated through air
quality modeling, used to develop the maintenance plans, it was
established that in using the 2030 PM10 and NOX
mobile source emissions derived with the elevated VMT, both maintenance
plans were still able to demonstrate maintenance of the PM10
NAAQS. In addition, the UDAQ further advised that the derived
PM10 and NOX MVEBs also contained an added
``safety margin'' of additional mobile sources emissions as described
in 40 CFR 93.124(a).
    During our review of both PM10 maintenance plans, we
noted that the elevated VMT numbers, used in part to develop the 2030
MVEBs, were not explicitly identified and quantified in the maintenance
plans or the associated TSD. This is necessary as per 40 CFR
93.118(e)(4)(iii) and 40 CFR 93.124(a). Based on a recommendation from
the EPA, the TSDs for each maintenance plan were subsequently
supplemented by the UDAQ to appropriately detail the derivation of the
2030 VMT figures, the associated PM10 and NOX
mobile source emissions, and the 2030 MVEBs. This additional,
supplemental TSD information was included with a submittal letter from
the Governor dated February 21, 2019, which is provided in the docket.
    Based on our above evaluation and our review of the submitted
additional TSD supplemental technical information, we have determined
that the three maintenance plans appropriately address the applicable
transportation conformity requirements in 40 CFR 93, Subpart A and we
are proposing approval of the 2030 PM10 and NOX
MVEBs as described above.

E. Did Utah follow the proper procedures for adopting this action?

    Section 110(k) of the CAA addresses our actions on submissions of
revisions to a SIP. The Act also requires states to observe certain
procedural requirements in developing implementation plans and plan
revisions for submission. Section 110(a)(2) of the Act provides that
each implementation plan submitted by a state must be adopted after
reasonable notice and public hearing. Section 110(l) of the Act
similarly provides that each revision to an implementation plan
submitted by a state under the Act must be adopted by such state after
reasonable notice and public hearing.
    We also must determine whether a submittal is complete and
therefore warrants further review and action (see section 110(k)(1) of
the Act and 57 FR 13565, April 16, 1992). Our completeness criteria for
SIP submittals are set out at 40 CFR part 51, appendix V. We attempt to
make completeness determinations within 60 days of receiving a
submission. However, a submittal is deemed complete by operation of law
under section 110(k)(1)(B) of the Act if a completeness determination
is not made within six months after receipt of the submission.
    On September 2, 2015, the Utah Air Quality Board proposed for
public comment for the Salt Lake County, Utah County and Ogden City
maintenance plans and redesignation requests. The public comment period
was held from October 1, 2015, to November 2, 2015. Comments were
submitted by industry, environmental associates, and the EPA. The EPA
submitted written comments dated November 2, 2015, on Utah's draft
PM10 maintenance plans and TSD. On December 2, 2015, the
Utah Air Quality Board adopted R307-110-10, Utah SIP Subsections
IX.A.11, IX.A.12, and IX.A.13 and it became effective on December 3,
2015. UDAQ submitted these revisions to the EPA on January 4, 2016.
Additionally, on March 6, 2019, the Governor of Utah submitted a
redesignation request for the Salt Lake County, Utah County and Ogden
City PM10 NAAs and included supplemental information. This
information was necessary in order to complete our review of the
maintenance plans and technical support information.

III. Proposed Action

    We are proposing to approve the Governor of Utah's submittal of
January 4, 2016, that contains revisions to R307-110-10 and the
PM10 maintenance plans for Salt Lake County, Utah County and
Ogden City PM10 NAAs. We are also proposing to approve the
Governor of Utah's submittal of March 6, 2019, that contains the
redesignation requests for the Salt Lake County, Utah County and Ogden
City PM10 NAAs to attainment for the 1987 PM10
standards and provided supplemental information. We are using 2016-2018
ambient air quality data from Salt Lake County, Utah County and Ogden
City NAAs as the basis for our decision. In addition, we are approving
the emissions inventories found within the maintenance plans to cover
the one element of the Moderate PM10 nonattainment SIP that
was not suspended with the CDD for the Ogden City NAA.
    We are proposing to approve this redesignation request, the
maintenance plans, and R307-110-10 revisions because UDAQ has
adequately addressed all of the requirements of the Act for
redesignation to attainment applicable to the Salt Lake County, Utah
County and Ogden City PM10 NAAs. Upon the effective date of
a subsequent final action, the Salt Lake County, Utah County and Ogden
City areas designation status under 40 CFR part 81 will be revised to
attainment.
    We are also proposing to approve R307-110-17 and revisions for
Section IX.H.1 and 2 that were submitted on February 15, 2019, and with
non-substantive changes submitted on July 1, 2019, August 20, 2019, and
on October 15, 2019. Additionally, we are proposing approval of the
revisions in R307-302 for incorporation into the Utah SIP as submitted
by the State of Utah on May 9, 2013, May 20, 2014, September 8, 2015
and February 27, 2017. This proposal will complete the EPA's October
19, 2016 (81 FR 71988) conditional approval action on the May 9, 2013,
May 20, 2014 and September 8,

2015 submittals for R307-302 from UDAQ.

IV. Incorporation by Reference

    In this document, the EPA is proposing to include regulatory text
in an EPA final rule that includes incorporation by reference. In
accordance with requirements of 1 CFR 51.5, the EPA is proposing to
incorporate by reference revisions to R307-110-10; R307-110-17; R307-
302; Section IX.H.1 and 2; maintenance plans for Salt Lake County, Utah
County and Ogden City PM10 NAAs; and the Governor of Utah's
redesignation requests for Salt Lake County, Utah County and Ogden City
PM10 NAAs to attainment. The EPA has made, and will continue
to make, these materials generally available through
www.regulations.gov and at the EPA Region 8 Office (please contact the
person identified in the For Further Information Contact section of
this preamble for more information).

V. 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
action merely proposes to approve state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2,
2017) regulatory action because SIP approvals are exempted under
Executive Order 12866;
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
     Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian tribe has
demonstrated that a tribe has jurisdiction. In those areas of Indian
country, the proposed rule does not have tribal implications and will
not impose substantial direct costs on tribal governments or preempt
tribal law as specified by Executive Order 13175 (65 FR 67249, November
9, 2000).

List of Subjects

40 CFR Part 52

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

40 CFR Part 81

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

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

    Dated: November 15, 2019.
Gregory Sopkin,
Regional Administrator, EPA Region 8.
[FR Doc. 2019-25176 Filed 11-20-19; 8:45 am]
 BILLING CODE 6560-50-P