[Federal Register Volume 84, Number 225 (Thursday, November 21, 2019)]
[Proposed Rules]
[Pages 64245-64260]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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

[[Page 64246]]

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, (303) 312-6602, [email protected].

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-

[[Page 64247]]

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
----------------------------------------------------------------------------------------------------------------
                                                                Mass based      Concentration      Alternative
            Source              Pollutant     Process unit     limits (tpd)     based limits     emission limits
----------------------------------------------------------------------------------------------------------------
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
----------------------------------------------------------------------------------------------------------------
tpd = tons per day.


[[Page 64248]]


     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
----------------------------------------------------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------
* 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.

[[Page 64249]]

 
                              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
----------------------------------------------------------------------------------------------------------------
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.

[[Page 64250]]



                         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.
---------------------------------------------------------------------------

    \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

[[Page 64251]]

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

[[Page 64252]]

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 .

[[Page 64253]]



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

[[Page 64254]]

 
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.

[[Page 64255]]

    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,

[[Page 64256]]

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

[[Page 64257]]

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

[[Page 64258]]

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:

[[Page 64259]]



  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,

[[Page 64260]]

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