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Proposed Rule

Approval and Promulgation of Implementation Plans; State of Utah; Logan, Utah-Idaho PM2.5

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Start Preamble

AGENCY:

Environmental Protection Agency.

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing to approve the request by the State of Utah to redesignate the Logan, Utah-Idaho (UT-ID) nonattainment area (NAA) (“Logan NAA”) to attainment status for particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 microns (PM2.5), and to approve related State Implementation Plan (SIP) revisions submitted by the State of Utah on November 5, 2019, and January 13, 2020. The redesignation request documents that the area has attained the 2006 PM2.5 National Ambient Air Quality Standards (NAAQS) and provides supporting information. The November 5, 2019 submittal includes revisions to Utah's R307-110-31 and R307-110-36 rules, concerning SIP Sections X.A and X.F. The January 13, 2020 submittal includes revisions to UAC R307-110-10 and the maintenance plan for the Logan NAA, which demonstrates attainment through the year 2035. The EPA is taking this action pursuant to the Clean Air Act (CAA or the Act). A separate EPA redesignation rulemaking will be conducted for the Idaho portion of the Logan NAA.

DATES:

Written comments must be received on or before March 29, 2021.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-R08-OAR-2020-0021, to the Federal Rulemaking Portal: https://www.regulations.gov. Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from www.regulations.gov. The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit http://www2.epa.gov/​dockets/​commenting-epa-dockets.

Docket: All documents in the docket are listed in the www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available electronically in www.regulations.gov. To reduce the risk of COVID-19 transmission, for this action we do not plan to offer hard copy review of the docket. Please email or call the person listed in the FOR FURTHER INFORMATION CONTACT section if you need to make alternative arrangements for access to the docket.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Crystal Ostigaard, Air and Radiation Division, Environmental Protection Agency (EPA), Region 8, Mailcode 8ARD-QP, 1595 Wynkoop Street, Denver, Colorado 80202-1129, (303) 312-6602, ostigaard.crystal@epa.gov.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Throughout this document wherever “we,” “us,” or “our” is used, we mean the EPA.

I. Background

A. Statutory and Regulatory Background for EPA's Regulation of PM 2.5

Under section 109 of the Act, the EPA has promulgated NAAQS for certain pollutants, including PM2.5. Once the EPA promulgates a NAAQS, section 107 of the Act specifies a process for the designation of each area 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 PM2.5, 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 to gain EPA approval.[1] For NAAs, SIPs must meet additional requirements 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.

On October 17, 2006 (71 FR 61144), the EPA revised the level of the 24-hour PM2.5 NAAQS, lowering the primary and secondary standards from the 1997 standard of 65 micrograms per cubic meter (µg/m3) to 35 µg/m3. On Start Printed Page 11695November 13, 2009 (74 FR 58688), the EPA designated three areas in Utah as Moderate NAAs for the 2006 24-hour PM2.5 NAAQS of 35 µg/m3: The Salt Lake City, Provo, and Logan NAAs.

The Logan NAA is composed of portions of Cache County, UT and Franklin County, ID. The Cache Valley is an isolated, bowl-shaped valley measuring approximately 60 kilometers north to south and 20 kilometers east to west, almost entirely surrounded by mountain ranges. The Wellsville Mountains lie to the west, and on the east lie the Bear River Mountains; both are northern branches of the Wasatch Range. The State of Utah views topography as a barrier to air movement during the conditions that lead to elevated concentrations of fine particulates, and as the primary factor in determining where the population is located. The low-lying valleys that trap air during wintertime temperature inversions are also the regions where most people live. Additional information pertaining to the unique issues associated with the Logan NAA and studies completed on inversions can be found in the 9-factor analysis for Utah and Idaho in the November 13, 2009 (74 FR 58688) action, “Air Quality Designations for the 2006 24-Hour Fine Particulate (PM2.5) National Ambient Air Quality Standards.”

The EPA issued a rule in 2007 [2] regarding implementation of the 2006 24-hour PM2.5 NAAQS for the NAA requirements specified in CAA title I, part D, subpart 1. Under subpart 1, Utah was required to submit an attainment plan for each area no later than three years from the date of nonattainment designation, addressing the requirements listed in section 172 of the Act. These plans needed to provide for the attainment of the PM2.5 standards as expeditiously as practicable, but no later than five years from the date the areas were designated nonattainment.

In 2013, the U.S. Court of Appeals for the District of Columbia held that the EPA should have implemented the 2006 PM2.5 24-hour standards, as well as the other PM2.5 NAAQS, based on both subpart 1 (sections 171-179B) and subpart 4 (sections 188-190) of CAA title I, part D.[3] Under subpart 4, all NAAs are initially classified as Moderate, and Moderate area attainment plans must address the requirements of subpart 4 as well as subpart 1. Additionally, subpart 4 sets a different SIP submittal due date and attainment year. For a Moderate area, the attainment SIP is due 18 months after designation and the attainment year is as expeditiously as practicable, but no later than the end of the sixth calendar year after designation. Therefore, as a result of the 2013 NRDC decision the State of Utah was required to submit an attainment plan addressing subpart 4 requirements in addition to subpart 1. EPA established the related deadlines in the Identification of Nonattainment Classification and Deadlines for Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine Particulate (PM2.5) National Ambient Air Quality Standard (NAAQS) and 2006 24-hour PM2.5 NAAQS rule, published on June 2, 2014 (79 FR 31566). This rule classified as Moderate the areas that were designated in 2009 as nonattainment and set the attainment SIP submittal due date for those areas at December 31, 2014. Additionally, this rule established the Moderate area attainment date as December 31, 2015.

Under subparts 1 and 4, the State was required to include the following elements in its Moderate attainment plan:

1. A comprehensive, accurate, current inventory of actual emissions from all sources of PM2.5 and PM2.5 precursors in the area. CAA section 172(c)(3).

2. Provisions to assure that reasonably available control measures (RACM), including reasonably available control technologies (RACT), for the control of direct PM2.5 and PM2.5 precursors, shall be implemented no later than four years after the area is designated. CAA sections 172(c)(1) and 189(a)(1)(C).

3. A demonstration (including air quality modeling) that the plan provides for attainment as expeditiously as practicable but no later than the Moderate area attainment date. CAA section 188(c)(1).

4. Plan provisions that require reasonable further progress (RFP). CAA section 172(c)(2).

5. Quantitative milestones, which are to be achieved every three years until the area is redesignated to attainment, and which demonstrate RFP toward attainment by the applicable date. The State is required to submit, not later than 90 days after the date on which a milestone applicable to the area occurs, a demonstration that all measures in the approved SIP have been implemented and the milestone has been met. CAA section 189(c); 40 CFR 51.1013(b). These submissions are referred to as “quantitative milestone reports.”

6. Provisions to assure that control requirements applicable to major stationary sources of PM2.5 also apply to major stationary sources of PM2.5 precursors, except where the state demonstrates to the EPA's satisfaction that such sources do not contribute significantly to PM2.5 levels that exceed the standard in the area. CAA section 189(e).

7. Contingency measures to be implemented if the area fails to meet RFP or fails to attain by the applicable attainment date. CAA section 172(c)(9).

8. A revision to the Nonattainment New Source Review (NNSR) program to set the applicable “major stationary source” thresholds to 100 tons per year (tpy). CAA section 302(j). Moderate area 2006 24-hour PM2.5 attainment plans must also satisfy the general requirements applicable to all SIP submissions under section 110 of the CAA, including the requirement to provide necessary assurances that the implementing agencies have adequate personnel, funding, and authority under CAA section 110(a)(2)(E), and the requirements concerning enforcement in CAA section 110(a)(2)(C).

On August 24, 2016 (81 FR 58010), the EPA finalized the Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements rule (“PM2.5 Requirements Rule”), which further addressed the 2013 NRDC decision. The final PM2.5 Requirements Rule details how air agencies can meet the SIP requirements under subparts 1 and 4, such as general requirements for attainment plan due dates and attainment demonstrations; provisions for demonstrating RFP; quantitative milestones; contingency measures; NNSR permitting programs; and RACM (including RACT).

B. Utah's PM 2.5 Attainment and SIP Status

On September 8, 2017 (82 FR 42447), the EPA granted two one-year extensions to the Moderate attainment date for the 2006 24-hour PM2.5 Logan NAA. The Moderate attainment date was originally December 15, 2015, and the granting of these two extensions changed the attainment date to December 31, 2017.

On October 19, 2018 (83 FR 52983), the EPA finalized a determination that the Logan PM2.5 NAA had attained the 2006 primary and secondary 24-hour PM2.5 NAAQS by the December 31, 2017 attainment date. Additionally, the EPA finalized a determination that the obligation to submit several remaining attainment-related SIP revisions arising from classification of the area as a Moderate NAA under subpart 4 of part D (of title I of the Act) for the 2006 24-hour PM2.5 NAAQS is not applicable Start Printed Page 11696under the Clean Data Policy [4] for so long as the area continues to attain the 2006 24-hour PM2.5 NAAQS. After this determination, the State of Utah was no longer obligated to submit an attainment demonstration, a demonstration that RACM (including RACT) shall be implemented no later than 4 years following the date of designation of the area, a RFP plan, quantitative milestones and quantitative milestone reports, and contingency measures. The State's remaining obligations include a baseline emissions inventory and a revised NNSR threshold. Also, for the Logan area to be redesignated to attainment, the State of Utah must still meet the statutory requirements for redesignation,[5] as described in the EPA's “Procedures for Processing Requests to Redesignate Areas to Attainment” guidance document.[6]

The suspension of planning requirements pursuant to 40 CFR 51.1015 does not preclude the State from submitting suspended elements of its Moderate area attainment plan, nor does it preclude the EPA from approving suspended elements, for the purpose of strengthening the SIP. Accordingly, the EPA approved portions of the Logan NAA SIP on October 24, 2018 and November 23, 2018. On October 24, 2018, the EPA determined that the 2017 quantitative milestone report for the Logan PM2.5 NAA was adequate, which satisfied the quantitative milestone report requirement of CAA section 189(c) and 40 CFR 51.1013(b). The determination letter from the EPA Administrator to the Governor of Utah is in the docket for this action.

Finally, on November 23, 2018, the EPA approved portions of the Logan PM2.5 SIP (83 FR 59315) contained in Utah Administrative Code (UAC) R307-110-10, Section IX, Control Measures for Area and Point Sources, Part A, Fine Particulate Matter. The portions of the SIP that were approved include: (1) The emission inventory (satisfying the inventory requirement of CAA section 172(c)(3)); (2) modeled attainment demonstration; (3) determination for Major Stationary Source RACT; (4) determination for On-Road Mobile Sources RACM; (5) the state's determination that the previously approved [7] Cache County Inspection and Maintenance (I/M) Program constituted additional RACM; (6) determination for Off-Road Mobile Sources RACM; and (7) 2015 Motor Vehicle Emission Budgets (MVEB). Additionally, R307-110-10 incorporates by reference (IBRs) Utah SIP Section IX, Control Measures for Area and Point Sources, Part A, Fine Particulate Matter.

On July 25, 2019 (84 FR 35832), the EPA approved revisions to R307-403, Permits: New and Modified Sources in Nonattainment Areas and Maintenance Areas. This rule covers the CAA's NNSR requirements for PM2.5 NAAs. In Section II.B. below we briefly discuss this NNSR requirement and how the July 25, 2019 action addresses it as to the Logan NAA.

C. Redesignation Requests and Related Requirements

For a NAA to be redesignated to attainment, the following conditions in section 107(d)(3)(E) of the CAA must be met:

1. We must determine that the area has attained the NAAQS;

2. The applicable implementation plan for the area must be fully approved under section 110(k) of the Act;

3. 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;

4. We must fully approve a maintenance plan for the area as meeting the requirements of CAA section 175A; and

5. The state containing the area must meet all requirements applicable to the area under section 110 and part D of the CAA.

In the Calcagni Memorandum the Agency explains how it assesses the adequacy of redesignation requests against the conditions listed above.

On January 13, 2020, the Governor of Utah submitted revisions to the SIP for R307-110-10, a maintenance plan for the Logan area (Utah SIP Section IX.A.28), and a request that the EPA redesignate this area to attainment for the 2006 24-hour PM2.5 NAAQS. R307-110-10 IBRs Section IX, Control Measures for Area and Point Sources, Part A, Fine Particulate Matter; which formally incorporates the Logan 2006 24-hour PM2.5 Maintenance Plan (located within the Utah SIP at Section IX.A.28) into Utah's State regulations. In Section II.C below, we discuss our review of the Utah Division of Air Quality (UDAQ) maintenance plan and redesignation request for the Logan 2006 24-hour PM2.5 NAAs.

II. The EPA's Evaluation

A. Utah's SIP Revisions

When the Utah SIP is amended by the Utah Air Quality Board (UAQB), the amended sections must be incorporated into the Utah Air Quality Rules. Utah incorporates SIP sections into the State's rule R307-110. These rules are amended as needed to change the effective dates to match the UAQB approval date of various amendments to the Utah SIP. In this action we are proposing to approve submitted revisions to: (1) R307-110-10, which IBRs Section IX, Control Measures for Area and Point Sources, Part A, Fine Particulate Matter, and thus incorporates the Logan 2006 24-hour PM2.5 maintenance plan into State regulations (located within the Utah SIP at Section IX.A.28); and (2) R307-110-31 and R307-110-36, which IBR Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability, and Section X, Vehicle Inspection and Maintenance Program, Part F, Cache County, which incorporate the general requirements and applicability of the I/M Programs in the State of Utah and the I/M Program of Cache County into the State regulations. Our evaluation of these revisions follows.

1. R307-110-10

Section R307-110-10 incorporates amendments to Utah SIP Section IX.A into State regulations, thereby making them effective as a matter of State law. This is a ministerial provision, which only revises the effective date within the rule to December 4, 2019 and does not itself include any SIP measures.

2. R307-110-31

Section R307-110-31 incorporates the amendments to Utah SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability, into State rules, thereby making them effective as a matter of State law. This is a ministerial provision, which only revises the effective date within the rule to September 4, 2019 and does not itself include any control measures.

3. R307-110-36

Section R307-110-36 incorporates the amendments to Utah SIP Section X, Start Printed Page 11697Vehicle Inspection and Maintenance Program, Part F, Cache County, into State rules, thereby making them effective as a matter of State law. This is a ministerial provision, which only revises the effective date within the rule to September 4, 2019 and does not itself include any control measures.

4. Subsection X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability

The revisions to “Part A, General Requirements and Applicability” include additions to section “1. General Requirements” that address the following revisions to Utah Code Annotated (UCA) Section 41-6a-1642:

a. An amendment in 2013 to include the date that notice is required and the date the enactment, change, or repeal will take effect if a county legislative body enacts, changes, or repeals the local emissions compliance fee. Section 41-6a-1642 provides that for a county that is required to implement a new vehicle emissions I/M program, but for which no current federally approved SIP exists, a vehicle shall be tested at a frequency determined by the county legislative body, in consultation with the UAQB, that is necessary to comply with federal law or attain or maintain any NAAQS. The section also establishes procedures and notice requirements for a county legislative body to establish or change the frequency of a vehicle emissions I/M program.

b. An amendment in 2017 to UCA Section 41-6a-1642 to allow a county that imposes a local emissions compliance fee to use revenue generated from the fee to promote programs to maintain a NAAQS. Section 41-6a-1642 was also amended to state that vehicles may not be denied registration based solely on the presence of a defeat device covered in the Volkswagen partial consent decrees or an EPA-approved vehicle emission modification.

c. An amendment in 2019 regarding “Notification of Programmatic Changes.” This requires that county legislative bodies consult with the Director of the UDAQ before their public comment process for any amendments to their I/M regulations or ordinances. Consultation is to include a written notice describing the proposed changes to the I/M program.

The revisions to Part A (General Requirements and Applicability) also included changes to section 3 (General Summary) that addressed minor wording clarifications to the subsections entitled “Out-of-state exemption” and “Vehicle inspection report.”

We have evaluated the Governor's November 5, 2019 submittal of the above revisions to the Utah SIP Section X Part A and are proposing approval.

5. Subsection X, Vehicle Inspection and Maintenance Program, Part F, Cache County

Section X, Part F of the Utah SIP addresses requirements for the implementation of the motor vehicle I/M program in Cache County. Section X, Part F of the SIP contains three main components for the Cache County I/M program: (1) Language addressing applicability, a general description of the program, and the time frame for its implementation; (2) the Cache County Emission Inspection/Maintenance Program Ordinance 2018-15; and (3) the Bear River Health Department's (BRHD) Regulation 2013-04. We note that the Cache County Ordinance 2018-15 contains language that delegates the implementation of the Cache County I/M program to the BRHD.

a. Under the heading “1. Applicability,” the revisions to the Cache I/M program note that the Cache I/M program was approved by the EPA on October 9, 2015 (80 FR 54237), and that the I/M program has been fully implemented.

b. Under the heading “2. Description of Cache I/M programs,” the revisions to the Cache I/M program include:

(1) “Subject Fleet”: The subject fleet for an I/M inspection was changed from 1969 and newer to 1996 and newer. This change reflects the County's revision to its I/M program to remove the Two Speed Idle (TSI) test for vehicles 1995 and older. Our proposed approval of this I/M program relaxation is discussed further below in section vii.

(2) “Test Frequency”: This section was also revised to reflect that model year 1996 and newer vehicles are subject to a biennial I/M test. This revised language also shows the removal of a required I/M test for 1995 and older vehicles.

(3) “Test Equipment”: This section was modified to remove the phrase “Analyzer calibration specifications” and replace it with “Certified testing equipment.”

(4) “Test Procedures”: This section was revised to remove the TSI test for 1995 and older vehicles and to remove the County's TSI test for 1996 to 2007 medium-duty vehicles and 2008 and newer heavy-duty vehicles. As noted above, we provide additional discussion on this I/M program relaxation in section vii below.

c. Under the heading “3. I/M SIP Implementation,” the revisions to the Cache I/M program involve the new language described below. This section notes that the I/M program ordinance, regulations, policies, procedures, and activities specified in the I/M SIP revision shall be implemented by January 1, 2021.

(1) The revisions to Cache County's Ordinance 2013-04 (Implementation of a Vehicle Emissions and Maintenance Program in Cache County) involved:

(a) Revisions to the table of contents that reflect the removal of the TSI test in 2021, and renumbering of subsequent subsections.

(b) Revisions to section 1.0 (Definitions) to remove several definitions and to modify and add several definitions.

(c) Revisions to section 2.0 (Purpose) to clarify that the ordinance complies with applicable federal requirements and with Cache County Code Chapter 10.20.

(d) Revisions to section 3.0 (Authority and Jurisdiction of the Department) to revise subsections to indicate the authority is as per Cache County Code Chapter 10.20 and its subdivisions.

(e) Revisions to section 4.0 (Powers and Duties) to remove unneeded references to Technical Bulletins and to include “Certified Testing “Equipment” in place of “testing equipment.”

(f) Revisions to section 5.0 (Scope) to remove the unneeded reference to Technical Bulletins.

(g) Revisions to section 6.0 (General Provisions) updating the applicability to vehicles registered in Cache County or principally operated there; adding references to Cache County Code Chapter 10.20 and its applicable subdivisions; updating the reference to UAC Section 41-6a-1642(10); revising the list of vehicles that are exempted from I/M testing; clarifying the required I/M testing station signs; and inserting a new “Compliance Assurance List” section 6.8 with its requirements.

(h) Revisions to section 7.0 (Permit Requirements of the Vehicle Emissions I/M Program Station) removed unneeded language relevant to TSI testing and adding language that a wireless internet connection may be required.

(i) Revisions to section 8.0 (Training and Certification of Inspectors) added “Certified Testing Equipment” where “test equipment” previously appeared. The revisions also removed unneeded language relevant to TSI testing and the unneeded requirement for a “hands on” test. The revisions added language in new section 8.4.3 that an emission inspection certificate would not be issued to an inspector applying in Cache County who has a revoked or suspended certificate in another county.Start Printed Page 11698

(j) Revisions to section 9.0 (Inspection Procedure) remove most of the inspection procedures from this section and place them instead in the revised Appendix D “Test Procedures.” In addition, language relating to the TSI test was removed and clarifying language referencing a “Certified Emissions Inspector” and “Certified Testing Equipment” has been added. Other revisions were made regarding “Waivers,” emissions related repairs, and language in the new section 9.6 regarding the exploration of new emission inspection technologies that would be vetted with, and approved by, Cache County, the State, and the EPA.

(k) Revisions to section 10.0 (Engine Switching) involve clarification of the term “EPA policy” by including the reference to specific EPA policies (i.e., the EPA's March 1991 engine switching Fact Sheet and its September 1997 Memorandum 1a) and language clarifying the requirements that a vehicle with an engine that was switched meet the emission inspection requirements of Section 6.0.

(l) Revisions to section 1.0 (Specifications for Certified Testing Equipment) remove previously applicable requirements for calibration gases, gas calibration with leak checks, and warranty and maintenance requirements, as these provisions were only applicable to the TSI test.

(m) Revisions to section 12.0 (Quality Assurance) update references to “Certified Testing Equipment.”

(n) Revisions to prior section 13.0 (Cutpoint Standards for Motor Vehicle Exhaust Gases) remove this section in its entirety, as it was only applicable to the TSI test.

(o) Revisions to renumbered section 13.0 (Disciplinary Penalties and Right to Appeal) renumber subsections and replace the term “audit” with “inspection.”

(p) Revisions to renumbered section 14.0 (Penalty) involved the renumbering of the prior subsections to a new subsection 14.6 that states the Department shall request that the Utah Division of Motor Vehicles (DMV) revoke the registration of any vehicle that is unable to meet the required emissions standards or has not complied with the required emissions testing requirements of UAC Section 41-1a-110(6).

(q) Revisions to renumbered section 15.0 (Severability) only involve the renumbering of the section.

(r) Revisions to renumbered section 16.0 (Effective Date) involve the renumbering of the section and change from the prior effective date of May 27, 2015 to January 1, 2021.

(s) Revisions to Appendix A only remove the reference to the fee for a TSI test.

(t) Revisions to Appendix B remove Appendix B in its entirety as it related to motor vehicle emissions cut-points applicable to the TSI test. As the TSI test was removed from the ordinance, this prior Appendix B is no longer relevant and was removed. The Appendix is now titled “Reserved.”

(u) Revisions to Appendix D (Test Procedures) involve the relocation of most of the On-Board Diagnostic (OBD) testing procedures to Appendix D that were previously located in section 9.0 (Inspection Procedure). Additional language, regarding the OBD test procedures, was included that clarifies, updates, and supplements the prior OBD test procedures language in the prior Appendix D. Terms were updated to refer to “Certified Emissions Equipment” and “Certified Emissions Inspector.” Provisions were added for a “Compliance Assurance Inspection” for a vehicle and a “Referee Inspection” at the County's I/M Technical Center for vehicles having difficulty with the OBD test, and also for when a vehicle owner believes the emission test done at an inspection station was not done correctly. The prior Appendix D test procedures for the TSI test were removed.

(v) Revisions to Appendix E (Certified Testing Equipment Standards) involved the removal of “Technical Specifications and Calibration Gas” from the Appendix title. All provisions and requirements for the TSI test were removed. Only the necessary provisions and requirements for the OBD test were retained and updated.

(w) Revisions to Appendix F (Waivers for Not Ready Vehicles) include clarifications to the provisions for the second and third tests, additional language regarding statements about the vehicle from the vehicle manufacturer's dealership repair station, and a new item number 6 addressing cost requirements for a waiver.

(x) Revision to Appendix G (Engine Switching) removing Appendix G in its entirety. The revised, allowable engine switching provisions were incorporated into section 10.0 above (Engine Switching).

We have evaluated the Governor's November 5, 2019 submittal of the above revisions to Utah SIP Section X Part F and are proposing approval.

(2) The revisions to Cache County's Ordinance 2013-04 (Implementation of a Vehicle Emissions and Maintenance Program in Cache County) for the removal of the TSI test in 2021.

In December 2018, the BRHD proposed to the Cache County Council to amend the Cache County vehicle emissions and maintenance program. The BRHD proposal was to discontinue the TSI test for vehicles 1995 and older due to a diminishing fleet of older light duty gasoline vehicles participating in the program, combined with increasing cost of maintaining the TSI testing equipment. The emission reductions benefit from these older vehicles was minimal compared to the resources required to operate the TSI test, and removal of the TSI test would not interfere with attainment and maintenance of the 2006 PM2.5 24-hour NAAQS.

The Cache County Council passed the proposal to discontinue the TSI program with an effective date of January 1, 2021. This effective date is reflected as part of the revisions to Ordinance 2013-04 discussed above. The TSI testing program covers light duty gasoline vehicles that are older than model year 1995 and was a component of the I/M control strategy used in the EPA-approved Logan PM2.5 Nonattainment SIP (83 FR 59315; November 23, 2018).

The UDAQ, EPA Region 8, and the BRHD coordinated regarding this Cache County I/M program relaxation to ensure that the proposed I/M program changes do not interfere with state and federal air quality regulations, as required under provisions of section 110(l) of the CAA. CAA section 110(l) allows revisions to a SIP to be approved so long as they do not interfere with any applicable requirement concerning attainment and RFP or any other applicable requirement of this chapter of the CAA. To evaluate the removal of the TSI test, the State prepared a CAA section 110(l) demonstration, as provided in Appendix A of the maintenance plan, and submitted that demonstration with the Governor's November 5, 2019 submittal.

On January 13, 2020, the Governor of Utah submitted the Logan PM2.5 maintenance plan, which contained the State's CAA section 110(l) demonstration for the removal of the I/M Program TSI biennial testing procedure for Cache County in 2021. Section 9 and Appendix A of the Logan PM2.5 maintenance plan show there will be minimal changes to the overall on-road mobile source emissions inventory within the Logan PM2.5 area. As noted in Table 3 below and detailed in Appendix A of the maintenance plan, overall mobile source emissions decrease from 2017 to 2021, through fleet turnover and Federal tailpipe standards. The state's demonstration considered on-road vehicle emissions Start Printed Page 11699from 2021-2026, as 2026 is the dispersion-modeled midpoint of the maintenance demonstration, and the dispersion modeling for 2035, which is the last year of the maintenance plan. In addition, the CAA section 110(l) demonstration considered whether there would be interference with other NAAQS being monitored in Cache County.

The State concluded that the removal of the TSI test will not interfere with the ability of the Logan area to continue to attain the 2006 24-hour PM2.5 NAAQS from 2017 through 2026 and in the last year of the maintenance plan, 2035. The State's analysis considered emissions credit assigned to the overall I/M program, including OBD and TSI test, within Cache County within the 2021-2026 period, and compared it to the emissions credit without the TSI program (OBD only). The mobile source emission estimates were based on meteorological conditions that occurred during three PM2.5 episodes: January 1-12, 2011; December 7-19, 2013; and February 1-17, 2016. Inventory estimations were created at the county level representing an average January weekday. The emission estimates were based on the EPA-approved MOVES2014b (May 2017 version) emissions model.

In addition, the demonstration considered PM2.5 ambient air quality monitoring data from the Smithfield, Cache County site and non-interference with the other five NAAQS. The State's full CAA section 110(l) demonstration is included in the Governor's November 1, 2019 submittal and is also provided in the docket to this action. The EPA's full review of the January 13, 2020 Logan PM2.5 maintenance plan and redesignation request submission is in section B, “What Requirements Must Be Followed for Redesignation to Attainment?” below.

EPA agrees with the State's CAA 110(l) demonstration regarding the removal of the I/M TSI for Cache County in 2021, in particular the conclusion that the removal will not have an adverse impact on the overall on-road mobile source inventory within the Logan PM2.5 area from 2017 to 2021 and through 2026. Further, the State's maintenance plan dispersion modeling for both 2026 and 2035 continues to show maintenance of the 2006 PM2.5 24-hour NAAQS even with this I/M program revision. In addition, the State has documented that the removal of the TSI test in 2021 will not impact the other NAAQS.[8]

Therefore, we are proposing to approve the removal of the TSI test component of the BRHD's Ordinance 2013-04 I/M program in 2021 for vehicles 1995 and older.

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

For a NAA to be redesignated to attainment, the following conditions in section 107(d)(3)(E) of the CAA must be met:

1. We must determine that the area has attained the NAAQS;

2. The applicable implementation plan for the area must be fully approved under section 110(k) of the Act;

3. 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;

4. We must fully approve a maintenance plan for the area as meeting the requirements of CAA section 175A; and,

5. The State containing the area must meet all requirements applicable to the area under section 110 and part D of the CAA.

EPA has provided guidance on redesignation in the “General Preamble,” [9] and has provided further guidance on processing redesignation requests in the following documents: (1) The Calcagni Memorandum; (2) “State Implementation Plan (SIP) Actions Submitted in Response to Clean Air Act (CAA) Deadlines,” Memorandum from John Calcagni, Director, Air Quality Management Division, October 28, 1992; and (3) “Part D New Source Review (Part D NSR) Requirements for Areas Requesting Redesignation to Attainment,” Memorandum from Mary D. Nichols, Assistant Administrator for Air and Radiation, October 14, 1994. These documents are included in the Docket for this proposed action.

On January 13, 2020, the Governor of Utah submitted revisions to the SIP for R307-110-10, a maintenance plan for the Logan area, and a request that the EPA redesignate the area to attainment for PM2.5. Additionally, on November 5, 2019, the State of Utah submitted revisions to R307-110-31 (Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability), R307-110-36 (Section X, Vehicle Inspection and Maintenance Program, Part F, Cache County), and revisions to SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability and revisions to SIP Section X, Vehicle Inspection and Maintenance Program, Part F, Cache County. The prior section discusses Utah's revisions to R307-110-10, R307-110-31, R307-110-36, Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability, and Section X, Vehicle Inspection and Maintenance Program, Part F, Cache County. The section below discusses how Utah's redesignation request and maintenance plan meet the requirements of the Act for redesignation of the Logan area to attainment for PM2.5.

C. Do the redesignation request and maintenance plan meet CAA requirements?

1. Attainment of the 2006 24-Hour PM2.5 NAAQS

To redesignate an area from nonattainment to attainment, the CAA requires the EPA to determine that the area has attained the applicable NAAQS (CAA section 107(d)(3)(E)(i)). On October 19, 2018, the EPA finalized a determination that the Logan NAA had attained the 2006 24-hour PM2.5 NAAQS, based on quality-assured and certified ambient air quality monitoring data for the period of 2015-2017 (83 FR 52983). The monitoring data used as the basis for the Determination of Attainment under 188(b)(2) is provided in Table 1, below.Start Printed Page 11700

Table 1—Logan NAA Design Values From 2018 Determination of Attainment Under 188(b)(2) 10

MonitorAQS site ID98th percentile value (µg/m3)2015-2017 design value
201520162017
Smithfield, UT49005000728.934.036.033
Franklin, ID16041000118.833.3a 38.3a 30
a This value includes 1 in 3 monitoring frequency from January 1-August 9, 2017, and daily monitoring frequency from August 10-December 31, 2017.

Whether an area has attainedthe 2006 24-hour PM2.5 NAAQS is based upon measured air quality levels at each eligible monitoring site with a complete three-year period to produce a design value equal to or below 35 µg/m3. A state must demonstrate that an area has attained the 2006 24-hour PM2.5 NAAQS through submittal of ambient air quality data from an ambient air monitoring network representing maximum PM2.5 concentrations. The data must be quality-assured, quality-controlled, and certified in the EPA's Air Quality System (AQS), and it must show that the three-year average of valid PM2.5 98th percentile mass concentrations is equal to or below the 2006 24-hour PM2.5 NAAQS (35 µg/m3), pursuant to 40 CFR 50.13. In making this showing, three consecutive years of complete air quality data must be used.

Between 2016 and 2019, Utah and Idaho operated at least one PM2.5 monitor in each state of the Logan NAA. In 2017, Idaho operated two PM2.5 monitors: Franklin, ID and Preston, ID. The Preston monitor did not begin operation until February 24, 2017, however, thus producing an incomplete first quarter for the monitoring year. Due to this incomplete quarter in 2017, the Preston monitor did not produce a valid design value for the 2017-2019 period. Despite this, EPA finds that it is appropriate to conclude that the area has indeed continued to attain the 2006 PM2.5 NAAQS since the initial 2015-2017 period upon which we based our October 19, 2018, Determination of Attainment, based on uninterrupted attainment at the Smithfield, UT monitor. A review of concurrent monitoring data for the Smithfield, UT and Preston, ID monitors provided in Table 2, below, shows that the Smithfield site consistently monitors higher levels of PM2.5 than the Preston site, indicating that Smithfield's location is more suitable to demonstrate maximum PM2.5 concentrations in the Cache Valley. Utah and Idaho completed a memorandum of understanding (MOU) to collectively meet the monitoring requirements of 40 CFR part 58, appendix D in the Logan UT-ID metropolitan statistical area (MSA), allowing Idaho to rely on the Smithfield monitor in Utah as the highest concentration monitor in the MSA.

As part of the redesignation request for the Logan NAA, UDAQ submitted quality-assured, complete and valid ambient air quality data from the Smithfield monitoring site which demonstrates that the area has attained the 2006 24-hour PM2.5 NAAQS.The EPA has reviewed the subsequent daily PM2.5 ambient air monitoring data in the Logan NAA, consistent with the requirements at 40 CFR part 50, and recorded in the EPA's AQS quality assured, quality-controlled, and State certified data for the monitoring design value [11] periods of 2016-2018 and 2017-2019. This air quality data demonstrates that the Logan NAA continues to attain the 2006 24-hour PM2.5 NAAQS. For the 2016-2018 3-year period, the Smithfield monitor produced a design value of 33 µg/m[3] .[12] The area's 24-hour PM2.5 design values for the 2017-2019 3-year period are provided in Table 2.

Table 2—Logan NAA Current PM2.5 98th Percentiles and Design Values 13

MonitorMonitor AQS No.98th percentile value (µg/m3)Design value (3-year average)
201720182019
Smithfield49005000736.027.935.133
Preston160410002a 17.327.230.1b NA
a The Preston monitor operated at a 1 in 3 monitoring frequency throughout 2017, and did not begin operation until February 24, 2017, making the first quarter incomplete for this monitor with less than 50% of data reported.
b Due to the incomplete first quarter in 2017, this design value does not meet validity requirements per 40 CFR part 50, appendix N, section 4.2(c)(i).

As Table 2 indicates, the Logan area has continued to attain the 2006 24-hour PM2.5 NAAQS since the EPA issued its determination of attainment under 188(b)(2) for the area based on the 2015-2017 design values shown in Table 1 above. The EPA's review of the monitoring data for 2016-2018 and 2017-2019 supports the previous determination that the area has attained the 2006 24-hour PM2.5 NAAQS and demonstrates that the area continues to attain the standard. Further information on PM2.5 monitoring is presented in Subsections IX.A.28.b(1) of the Utah portion of the Logan maintenance plan. We have evaluated the ambient air quality data and have determined that the Logan 2006 24-hour PM2.5 NAAQS NAA continues to attain the standard based on the available monitoring data.

A separate EPA redesignation rulemaking will be conducted for the Idaho portion of the Logan NAA.Start Printed Page 11701

2. State Implementation Plan Approval

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).

On February 25, 2016 (81 FR 9343), October 19, 2016 (81 FR 71988), October 2, 2019 (84 FR 52368), and February 26, 2020 (85 FR 10989) the EPA approved revisions to several area source rules and approved new rules for PM2.5 NAAs into the Utah SIP, including the Logan PM2.5 NAA.

On September 9, 2015 (80 FR 54237), the EPA finalized approval of SIP revisions to Utah's SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability; Section X. Vehicle Inspection and Maintenance Program, Part F, Cache County; and Utah Rule R307-110-1, R307-110-31, and R307-110-36, which IBR the Utah SIP into the Utah Rules, IBRs Utah SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability, and IBRs Utah SIP Section X, Vehicle Inspection and Maintenance Program, Part F, Cache County, respectively. Additionally, the EPA is acting on revisions to R307-110-31, R307-110-36, Utah's SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability, and on Section X. Vehicle Inspection and Maintenance Program, Part F, Cache County in this action. Our evaluation of these revisions is found in Section II.A.2, 3, 4, and 5 above.

Additionally, we completed a clean data determination (CDD) for the Logan PM2.5 NAA on October 19, 2018 (83 FR 52983). With this final rule, the EPA suspended the obligation for Utah to make submissions to meet certain CAA requirements related to attainment of the NAAQS. These suspended CAA requirements are: (1) Attainment demonstration; (2) projected emissions inventory; (3) RACM/RACT; (4) RFP; (5) MVEB; (6) contingency measures; and (7) quantitative milestones.

On November 23, 2018 (83 FR 59315), the EPA approved portions of the Logan PM2.5 SIP which were: The emissions inventory; modeled attainment demonstration; determination for Major Stationary Source RACT; determination for On-Road Mobile Sources RACM; determination for Cache County I/M Program as additional reasonable measures; determination for Off-Road Mobile Sources RACM; and the 2015 MVEB.

On July 25, 2019 (84 FR 35831), the EPA approved revisions to UAC R307-403 (Permits: New and Modified Sources in Nonattainment Areas and Maintenance Areas) into the SIP.

We have evaluated the actions above and have determined that through these actions, the State of Utah has a fully approved Logan PM2.5 SIP under section 110(k).

3. 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.

Utah has implemented multiple area source rules in the Logan NAA. On February 25, 2016 (81 FR 9343), October 19, 2016 (81 FR 71988), October 2, 2019 (84 FR 52368), and February 26, 2020 (85 FR 10989) the EPA approved revisions to several area source rules and approved new rules for PM2.5 NAAs into the Utah SIP, including the Logan PM2.5 NAA.

On September 9, 2015 (80 FR 54237), the EPA finalized approval of SIP revisions to Utah's SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability; Section X. Vehicle Inspection and Maintenance Program, Part F, Cache County; and to Utah Rule R307-110-1, R307-110-31, and R307-110-36, which IBR the Utah SIP into the Utah Rules, IBRs Utah SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability, and IBRs Utah SIP Section X, Vehicle Inspection and Maintenance Program, Part F, Cache County, respectively. Additionally, the EPA is acting on revisions to R307-110-31; R307-110-36; Utah's SIP Section X, Vehicle Inspection and Maintenance Program, Part A, General Requirements and Applicability; and on Section X. Vehicle Inspection and Maintenance Program, Part F, Cache County. Our evaluation of these revisions is found in Section II.A.2, 3, 4, and 5 above.

Additionally, within section IX.A.28.b.3. of the Logan PM2.5 maintenance plan, UDAQ provides an assessment of the ambient air quality data collected at the Logan PM2.5 monitor from the year monitoring began (2000) to 2018 (the last year of valid data before the maintenance plan was submitted), which shows an observable decrease in the monitored PM2.5. UDAQ observed both the 98th percentile average of the 24-hour data in the Logan PM2.5 NAA as well as the annual arithmetic mean which assisted in understanding the trends. The Logan PM2.5 NAA was only designated nonattainment for the 2006 24-hour PM2.5 NAAQS; however, it is useful information in showing the decrease in emissions. The cold-pool temperature inversions during the winter months, which drive and trap secondary PM2.5, vary in strength and duration from year to year, and the PM2.5 concentrations measured during these periods reflect this variability more than they reflect the gradual changes in emissions of direct PM2.5 and the PM2.5 precursors. This variability is evident in UDAQ's assessment, but when a line is fit through the 24-hour data, a trend is seen going downward and indicates improvement at 1 µg/m3 per year. This episodic variability is reduced when reviewing the annual mean values of PM2.5 concentrations from 2000-2018. This annual mean includes all the high values identified as the 98th percentiles, still the trend is downward. UDAQ fitted a line through the annual mean PM2.5 concentration data collected at the Logan PM2.5 NAA which revealed a decreasing trend and indicates an improvement of 5.6 µg/m3 over this 18-year span.

We have evaluated the various state and federal control measures, historical emissions inventories, and the emission trends of the PM2.5 98th percentiles and annual PM2.5 mean concentrations presented by UDAQ from 2000 to 2018, and have determined that the improvement in air quality in the Logan NAA has resulted from emission reductions that are permanent and enforceable.

4. 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 meeting 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, the 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 Start Printed Page 11702the NAAQS.[14] The EPA's interpretations of the CAA section 175A maintenance plan requirements are generally provided in the General Preamble and the Calcagni Memorandum referenced above. The Calcagni Memorandum outlines five core elements 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

PM2.5 maintenance plans should include an attainment emission inventory to identify the level of emissions in the area that is sufficient to maintain the NAAQS. An emissions inventory was developed and submitted with the Logan PM2.5 maintenance plan NAA on January 13, 2020. This submittal contains a base year of 2017, interim-year projected inventory for 2026, and a projected maintenance inventory of 2035. The emissions in the inventories include sources of PM2.5 and PM2.5 precursor emissions within a regional area called a modeling domain. UDAQ modeled two different domain sizes; 4 km coarse and 1.33 km fine.[15] The 4 km coarse domain covered the entire State of Utah, a significant portion of Eastern Nevada (including Las Vegas), and smaller portions of Idaho, Wyoming, Colorado, and Arizona. Since the coarse domain was so large, the 1.33 km fine domain or a “core area” within this domain was identified wherein a higher degree of spatial resolution was used in the model. Within this core area (which includes Weber, Davis, Salt Lake, Utah, Box Elder, Tooele, Cache, and Franklin, ID Counties), SIP-specific inventories were prepared to include seasonal adjustments and forecasting to represent each of the projection years. In the bordering region, the 2014 National Emissions Inventory (NEI) was used in the analysis. Four general categories of sources were included in these inventories: point sources; area sources; on-road mobile sources; and non-road mobile sources.

For each of these source categories, the pollutants inventoried were PM2.5, sulfur dioxide (SO2), NOX, VOC, and ammonia (NH3). More detailed descriptions of the 2017 base-year inventory and the 2026 and 2035 projection inventories can be found in section IX.A.28.c., Logan Maintenance Plan, subsection (2) Attainment Inventory, and within the State of Utah's technical support document (TSD). Utah's submittal contains detailed emission inventory information prepared in accordance with EPA emission inventory guidance.[16] Summaries of emission figures from the 2017 base year and the projected inventories are in Table 3 below.

Table 3—Logan NAA; Actual Emissions From 2017 and Emission Projections for 2026 and 2035

[Tons per day (tpd)]

YearSource categoryPM2.5 filterablePM2.5 condensiblePM2.5 totalNOXVOCNH3SO2
2017 BaselineArea Sources0.560.050.60.923.813.480.03
Non-Road0.10.792.1900
Point Sources0000000
Mobile Sources0.233.762.460.10.02
2017 Total0.935.478.4513.580.05
2026Area Sources0.600.040.640.73.8813.270.03
Non-Road0.060.591.2700
Point Sources0000000
Mobile Sources0.131.521.390.090.01
2026 Total0.832.816.5413.360.04
2035Area Sources0.630.040.670.714.2913.110.03
Non-Road0.050.571.0400
Point Sources0000000
Mobile Sources0.191.761.910.10.01
2035 Total0.913.047.2413.210.04

Based on our review, we have determined that Utah prepared an adequate attainment inventory for the Logan PM2.5 NAA.

b. Maintenance Demonstration

The Calcagni Memorandum states that where modeling was relied on to demonstrate maintenance, the plan must 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 demonstration for the Logan area used a regional photochemical model.

Before the development of the Logan PM2.5 maintenance plan, UDAQ conducted a technical analysis to support the development of the Serious SIP for the Salt Lake City, UT PM2.5 NAA. The analysis included preparation of emissions inventories and meteorological data, and the evaluation and application of a regional photochemical model. Part of this process included selection of the episode that most accurately replicates the photochemical formation of ambient PM2.5 during a persistent cold air pool episode in the airshed. For the Logan maintenance plan, UDAQ used the same episode that was used for the Serious SIP modeling.

The Comprehensive Air Quality Model with Extensions (CAMx) version 6.30 for air quality modeling was used for the Logan maintenance plan, with enhancements including snow chemistry and topographical and surface albedo refinements. The emissions processing model that UDAQ used in conjunction with CAMx was the Start Printed Page 11703Sparse Matrix Operator Kernel Emissions Modeling System (SMOKE) version 3.6.5. Meteorological inputs were derived using the Weather Research and Forecasting (WRF) Advanced Research WRF (WRF-ARW) model to prepare meteorological datasets for UDAQ to use with the photochemical model. UDAQ found that WRF-ARW was reasonably able to replicate the vertical temperature structure of the boundary layer (i.e., the winter temperature inversion in the NAA), but that WRF-ARW had difficulty reproducing the inversion when the inversion was shallow and strong (e.g., an 8-degree temperature increase over 100 vertical meters). UDAQ provides additional information on these models in their TSD.[17]

Part of the modeling exercise that UDAQ completed for the Logan maintenance plan was to test whether the model could successfully replicate the PM2.5 mass and composition that were observed during prior episode(s) of elevated PM2.5 concentrations. After consulting EPA guidance,[18] UDAQ selected three episodes: (1) January 1-10, 2011; (2) December 7-19, 2013; and (3) February 1-16, 2016. UDAQ examined the PM2.5 model performance for these three episodes and concluded that the CAMx performed the best when using the January 2011 WRF-ARW output. UDAQ further confirmed this determination by using a linear regression analysis showing that modeled and measured PM2.5 at the Logan monitoring station was strongly correlated during the January 2011 episode (R2 = 0.72) compared to the other episodes (R2 = 0.18 for the December 2013 episode, and R2 = 0.39 for the February 2016 episode). A comprehensive discussion of the meteorological model performance for all three of these episodes can be found in the TSD submitted by UDAQ.

UDAQ compared the 24-hour modeled and observed PM2.5 during the January 1-10, 2011 episode at the Logan monitoring station, and the results showed that overall, the model captured the temporal variation in PM2.5 well. This temporal variation included a gradual increase in PM2.5 concentration and its transition back to low levels. However, UDAQ discovered that despite the generally good representation of the temporal behavior of PM2.5, the concentrations were, generally, lower in the model on January 4-9, 2011. This was partly related to the meteorological model performance on these days where temperature was overestimated by 5 to 15 degrees Celsius, and thick, low-level clouds were simulated on January 5, 2011, while clouds were not observed for this day.[19] Due to this low-level cloud simulation produced from the model, an increasingly deep sub-cloud mixing layer in the model was observed compared to reality, which led to an underprediction in modeled PM2.5 concentrations. A more detailed analysis of this episode can be found in the Utah TSD.

Overall, UDAQ concluded that the model performance of replicating the buildup and clear out of PM2.5 in the Logan NAA was good, and thus, the model could be used for air quality planning purposes.

With acceptable model performance, the model can be utilized to make future-year attainment projections. 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, then compared to the NAAQS (35 µg/m3). An FDV below the NAAQS at every monitor in the NAA would demonstrate attainment for the area in that specific future year. A maintenance plan must demonstrate continued attainment of the NAAQS for a span of ten years. Since this ten-year span is measured from when the EPA takes final action on the maintenance plan, the exact ten-year date cannot be known before the plan is submitted. To be conservative, UDAQ projected an attainment date of 2035, which is fifteen years after Utah submitted the Logan maintenance plan. Additionally, UDAQ modeled a “spot-check” assessment of 2026.

In making future-year projections, the output from the CAMx 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 2017. This comparison results in a Relative Response Factor (RRF). An RRF greater than one indicates that according to the model, the predicted PM2.5 level is greater in the future year than in the 2017 base year, which typically is a result of increased emissions in the future year associated with projected population growth. (Additional discussion of the RRF can be found in the maintenance plan and the TSD submitted by UDAQ.) The FDV is calculated by multiplying the BDV by the RRF. FDV's are compared to the NAAQs in order to determine whether attainment is predicted at each monitoring location. Table 4 below provides FDV results for the Smithfield monitor and projection year and shows that no FDV exceeds the NAAQS. Therefore, continued attainment is demonstrated in the Logan NAA.

Table 4—Baseline Design Value, Relative Response Factors, and Future Design Values for All Monitors and Future Projection Years 20

Monitor2016-2018 BDV2026 RRF2026 FDV2035 RRF2035 FDV
Smithfield32.60.8628.00.8728.2

According to the Calcagni memorandum, any assumptions concerning emission rates must reflect permanent, enforceable measures. A state cannot take credit in the maintenance demonstration for reductions unless there are regulations in place requiring those reductions, or the reductions are otherwise shown to be permanent. States are expected to maintain implemented control strategies despite redesignation to attainment, unless measures that achieve equivalent reductions are approved into the SIP. Emission reductions from source shutdowns can be considered permanent and enforceable to the extent that those shutdowns have been Start Printed Page 11704reflected in the SIP and all applicable permits have been modified accordingly.

As part of the Moderate PM2.5 SIPs, 24 area source rules were either introduced or augmented by UDAQ to control PM2.5 and PM2.5 precursors. On February 25, 2016 (81 FR 9343), October 19, 2016 (81 FR 71988), October 2, 2019 (84 FR 52368), and February 26, 2020 (85 FR 10989), the EPA acted on area source rules for the Logan PM2.5 NAA. There are no changes to these area source rules with this action.

With respect to the part of Franklin County, ID that is included in the Logan NAA, UDAQ provided general information on Idaho's Moderate PM2.5 SIP and what EPA's Region 10 office had acted on for control measures. On January 4, 2017 (82 FR 729) and on March 25, 2014 (79 FR 16203), the EPA approved the residential woodstove curtailment program/change-out program and the road sanding agreements, respectively, as voluntary measures. Additional information on Idaho's SIP will be available when EPA's Region 10 office acts on Idaho's portion of the Logan maintenance plan.

Based on the information described above and in our TSD, the EPA proposes to find that Utah has adequately demonstrated that the Logan area will maintain the 2006 24-hour PM2.5 NAAQS for the next fifteen years.

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. Accordingly, the maintenance plan should contain provisions for continued operation of air quality monitors. As described in the maintenance plan, Utah will continue to maintain and operate a PM2.5 ambient monitoring network within the Logan PM2.5 area in accordance with 40 CFR part 58 and the Utah SIP. We approve these sites annually, and any future change would require discussion and approval from the EPA. In its January 13, 2020 submittal, Utah commits to continue to maintain an ambient monitoring network for PM2.5 in the Logan area, in accordance with 40 CFR part 58 and the Utah SIP.

d. Verification of Continued Attainment

Utah's maintenance plan submittal for the Logan area must indicate how the State will track the progress of the maintenance plan. This is necessary because the emissions projections made for the maintenance demonstrations depend on assumptions of point and area source growth. In Section IX.A.28.c.(7), Utah commits to track and document measured mobile source parameters (e.g., vehicle miles traveled, congestion, fleet mix) 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 maintenance plan to be approved under section 175A, a state is not required to have fully adopted contingency measures that will take effect without further action by the state. 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 in the Part D nonattainment plan for the area before redesignation. The state should also identify the specific indicators, or triggers, that will be used to determine when the contingency plan will be implemented.

As stated in Section IX.A.28.c.(8) of the Logan maintenance plan, triggering the contingency plan does not automatically require a revision to the SIP, nor does it necessarily mean the area will be reclassified to nonattainment. Instead, Utah will normally have an appropriate timeframe to correct the potential violation by implementing one or more adopted contingency measures. If violations continue to occur, additional contingency measures will be implemented until the violations are corrected.

Upon monitoring a potential violation of the 2006 24-hour PM2.5 NAAQS, including exceedances flagged as exceptional events but not concurred with by the EPA, the State will identify a means of corrective action within six months after a potential violation. Utah will require implementation of the corrective action no later than one year after the violation is confirmed, and any contingency measures adopted and implemented will become part of the next revised maintenance plan submitted for EPA approval.

The Logan maintenance plan list of contingency measures includes: (1) Reinstate TSI test portion of the Cache County I/M Program; (2) Measures to address emissions from residential wood combustion (i.e., emissions from fireplaces under the existing R307-302 rule), including re-evaluating the thresholds at which red or yellow burn days are triggered; (3) Measures to address fugitive dust from area sources; and (4) Additional measures to address other PM2.5 sources identified in the emissions inventory, such as on-road vehicles, and non-road vehicles and engines.

Based on the above, we propose to find that the contingency measures provided in the Logan PM2.5 maintenance plan are sufficient and meet the requirements of section 175A(d) of the CAA.

f. Subsequent Maintenance Plan Revisions

In accordance with section 175A(b) of the Act, Utah is required to submit a revision to the maintenance plan eight years after the redesignation of the Logan area to attainment for PM2.5. This revision is to provide for maintenance of the NAAQS for an additional ten years following the first ten-year period. In the Logan maintenance plan, Utah committed to submit a revised maintenance plan eight years after the approval of the redesignation request and maintenance plan.

5. 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) provides 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, Utah must have met all requirements that applied to the subject area as of the time of submitting a complete redesignation request. In our evaluation of a redesignation request, we don't 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 attainment plans. For purposes of redesignation, the Utah SIP was reviewed to ensure that all applicable requirements under the amended Act were satisfied. On September 21, 2010, the State submitted an Infrastructure SIP to the EPA demonstrating compliance with the Start Printed Page 11705requirements of section 110 that are applicable to the 2006 24-hour PM2.5 NAAQS. We approved this submittal on November 25, 2013 (78 FR 63883), for all section 110 requirements applicable to redesignation.

b. Part D Requirements

Before a PM2.5 NAA may be redesignated to attainment, a state must have fulfilled the applicable requirements of part D. Subpart 1 of part D establishes general requirements applicable to all NAAs, while subpart 4 of part D establishes specific requirements applicable to PM10/PM2.5 NAAs. The PM2.5 Requirements Rule provides that the applicable requirements of CAA section 172 are 172(c)(3) (emissions inventory), 172(c)(5) (NSR permitting program), 172(c)(7) (the section 110(a)(2) air quality monitoring requirements), and 172(c)(9) (contingency measures). Also, as explained in the Calcagni Memorandum, we interpret 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. 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 2006 24-hour PM2.5 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 February 25, 2016 (81 FR 9343), October 19, 2016 (81 FR 71988), October 19, 2018 (83 FR 52983), November 23, 2018 (83 FR 59315), October 2, 2019 (84 FR 52368), and February 26, 2020 (85 FR 10989) actions approving portions of the Moderate PM2.5 Logan SIP and CDD. The CDD suspended Utah's obligation to make a SIP submission, or supplement, for attainment-related requirements including an attainment demonstration, RACM/RACT, RFP, contingency measures, and milestone reports.

We approved the requirements of the part D NNSR permit program for Utah on July 25, 2019 (84 FR 35831). Once the Logan area is 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 Logan area 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 Logan area upon redesignation of the areas to attainment.

D. Have the transportation conformity requirements been met?

(i) Requirements for Transportation Conformity and Motor Vehicle Emissions Budgets (MVEB)

Transportation conformity is required by section 176(c) of the CAA. The EPA's conformity rule at 40 CFR part 93, subpart A requires that transportation plans, programs, and projects conform to SIPs and establishes the criteria and procedures for determining whether or not they conform. 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. To effectuate its purpose, the EPA's conformity rule requires a demonstration that emissions from a Metropolitan Planning Organization's (MPO) Regional Transportation Plan (RTP) and Transportation Improvement Program (TIP), involving Federal Highway Administration (FHWA) or Federal Transit Administration (FTA) funding or approval, are consistent with the MVEB(s) contained in a control strategy SIP revision or maintenance plan (40 CFR 93.101, 93.118, and 93.124). An MVEB is defined as the level of mobile source emissions of a pollutant relied upon in the attainment or maintenance demonstration to attain or maintain compliance with the NAAQS in the nonattainment or maintenance area. Further information concerning the EPA's interpretations regarding MVEBs can be found in the preamble to the EPA's November 24, 1993, transportation conformity rule.[21]

The EPA notes that a PM2.5 maintenance plan should identify MVEBs for direct PM2.5, NOX and all other PM2.5 precursors whose on-road mobile source emissions are determined to significantly contribute to PM2.5 levels in the area. We note that for the Logan PM2.5 maintenance plan SIP revision, the UDAQ also identified VOCs as a precursor to the formation of PM2.5 in the Logan PM2.5 area. For direct PM2.5 SIP MVEBs, the MVEB should include direct PM2.5 motor vehicle emissions from tailpipes, brake wear, and tire wear. In addition, a state must also consider whether re-entrained road dust is a significant contributor and should be included in the direct PM2.5 MVEB.[22] With respect to this requirement, the EPA reviewed information, data, and an analysis from the UDAQ that sufficiently documented that re-entrained road dust emissions were negligible and meet the criteria of 40 CFR 93.102(b)(3) for not needing to be included in the direct PM2.5 MVEB. The EPA concurred with the State's analysis in an email dated July 20, 2011 to UDAQ.[23]

(ii) MVEBs Identified in the Logan PM2.5 Maintenance Plan SIP

Utah's Logan PM2.5 maintenance plan SIP revision was submitted to meet the requirements of CAA section 175A and relevant EPA guidance.[24] The State's maintenance plan specified the maximum mobile source emissions of PM2.5, NOX and VOC allowed in the final maintenance year, which is 2035. These mobile source emissions were initially identified by the State as the maintenance plan's MVEBs. However, through additional sensitivity dispersion modeling, the State was able to demonstrate that for 2035, additional mobile sources emissions could be included such that the Logan area could continue to demonstrate maintenance. These additional direct PM2.5, NOX, and VOC mobile source emissions were then identified as a “safety margin” [25] and were then added to the initial MVEBs to arrive at the final MVEBs. This process of identifying an additional “safety margin” was correctly followed by the UDAQ and is allowed by 40 CFR 93.124(a). The derivation of the MVEBs, with a “safety margin,” is described in Section 4 “Mobile Source Budget for Purposes of Conformity” of the maintenance plan and Section “3.e. On-road Mobile Baseline and Projection Inventories, ii. On-Road MVEB Derivation” of the TSD. As presented in Table IX.A.28.9 of the maintenance plan, the final 2035 MVEBs were 0.2 tpd direct PM2.5, 2.02 tpd NOX, and 2.18 tpd VOCs.

We note that 40 CFR 93.118(b)(2)(i) indicates that for maintenance plans that do not identify MVEBs for any other year than the last year of the Start Printed Page 11706maintenance plan, the demonstration of consistency with the MVEBs by the applicable MPO must be accompanied by a qualitative finding that there are no factors that would cause or contribute to a new violation or exacerbate an existing violation in the years before the last year of the maintenance plan.

(iii) MVEBs Trading, for Purposes of Demonstrating Transportation Conformity, in the Logan PM2.5 Maintenance Area

The EPA's transportation conformity rule allows for trading between the direct PM2.5 and NOX and VOC precursor MVEBs where the SIP establishes an appropriate mechanism for such trades.[26] The basis for the trading mechanism is the maintenance plan's dispersion modeling demonstration for 2035, which established the relative contribution of the NOX and VOC precursor pollutants.

As discussed in Section 4(a)(ii) (“Trading Ratios for Transportation Conformity”) of the maintenance plan, the State established a MVEB trading mechanism to allow for future increases in on-road mobile sources direct PM2.5 emissions to be offset by future decreases in NOX precursor emissions from on-road mobile sources. This ratio was developed from data from the air quality maintenance plan's dispersion modeling. Section 4(a)(ii) of the maintenance plan and Section 6 of the maintenance plan's TSD provide the following modeling-derived trading ratio: Future increases in on-road mobile sources direct PM2.5 emissions may be offset with future decreases in NOX emissions from on-road mobile sources at a NOX to PM2.5 ratio of 3.4 to 1.

The maintenance plan also notes that this trading mechanism will only be used by the Cache MPO for transportation conformity determination analyses for years after 2035. The maintenance plan further notes that to ensure that the trading mechanism does not impact the ability to meet the NOX budget, the NOX emission reductions available to supplement the direct PM2.5 MVEB will only be those remaining after the 2035 NOX MVEB has been met. The maintenance plan further articulates that clear documentation of the calculations used in the MVEB trading must be included in the conformity determination analysis as prepared by the Cache MPO.

(iv) EPA's Evaluation of Mobile Source Revisions

The EPA has evaluated the Logan PM2.5 maintenance plan's emission inventories and maintenance demonstration modeling as described in the sections above. Based on our evaluation, we have determined that the direct PM2.5, NOX, and VOC MVEBs are appropriately derived from the maintenance plan and are acceptable. We have also evaluated the description and derivation of the MVEB NOX trading mechanism and the supporting data from the maintenance plan's maintenance demonstration modeling information and TSD and find it acceptable. Therefore, we are proposing to approve the Logan UT-ID PM2.5 maintenance plan's 2035 MVEBs of direct PM2.5 of 0.2 tpd, NOX of 2.02 tpd, and VOC of 2.18 tpd. In addition, we are proposing to approve the NOX to direct PM2.5 MVEB trading mechanism as described above and documented in Section 4(a)(ii) of the maintenance plan.

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 the state after reasonable notice and public hearing.

We also must determine whether a submittal is complete and therefore warrants further review and action.[27] Our completeness criteria for SIP submittals are 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 June 5, 2019, the UAQB proposed amendments to Utah SIP Section X, Vehicle Inspection and Maintenance Program, Parts A and F, R307-110-31, and R307-110-36. The comment period was held from July 1, 2019, to July 31, 2019. No comments were received, and no public hearing was requested. On September 4, 2019, the UAQB adopted revisions to R307-110-31, R307-110-36, and to Utah SIP Section X, Vehicle Inspection and Maintenance Program, Parts A and F. These revisions became effective on September 5, 2019, and UDAQ submitted these revisions to the EPA on November 5, 2019.

On September 4, 2019, the UAQB proposed for public comment the Logan maintenance plan and redesignation request and revisions to R307-110-10. The public comment period was held from October 1, 2019, to October 31, 2019. UDAQ received comments from industry and citizens; and no public hearing was requested. UDAQ provided the comments and their responses within the submittal. The comments did not prompt UDAQ to substantively revise any documents. UDAQ made a few minor revisions to the plan once the data and modeling were verified. On December 4, 2019, the UAQB adopted R307-110-10 and the Logan maintenance plan/redesignation request, and they became effective on December 5, 2019. UDAQ submitted these revisions and the TSD to the EPA on January 13, 2020.

III. Proposed Action

We are proposing to approve the Governor of Utah's submittal of January 13, 2020, which contains revisions to R307-110-10 and the Logan PM2.5 maintenance plan and redesignation request. We are also proposing to approve the Governor of Utah's submittal of November 5, 2019, which contains revisions to R307-110-31, R307-110-36, Utah SIP Section X.A., and Utah SIP Section X.F. We are proposing to approve the maintenance plan's 2035 MVEBs. In addition, we are also proposing to approve the NOX-to-direct-PM2.5 MVEB trading mechanism. We are proposing approval of these submissions because UDAQ has adequately addressed all requirements of the Act for the SIP revisions and the redesignation to attainment applicable to the Logan 2006 24-hour PM2.5 NAA. We are using 2017-2019 ambient air quality data from Logan NAA as the basis for our decision. We have evaluated the ambient air quality data and have determined that the Logan 2006 24-hour PM2.5 NAAQS NAA continues to attain the standard based on the available monitoring data. A separate EPA redesignation rulemaking will be conducted for the Idaho portion of the Logan NAA. Upon the effective date of a subsequent final action, the designation status of the Utah portion of the Logan area under 40 CFR part 81 will be revised to attainment.Start Printed Page 11707

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; R307-110-31; R307-110-36; Utah SIP Section X.A.; Utah SIP Section X.F.; maintenance plan for the Utah portion of the Logan PM2.5 NAA; and the redesignation request for the Logan PM2.5 NAA 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. Accordingly, 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).

Start List of Subjects

List of Subjects

40 CFR Part 52

  • Environmental protection
  • Air pollution control
  • Carbon monoxide
  • Greenhouse gases
  • Incorporation by reference
  • Intergovernmental relations
  • 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
End List of Subjects Start Authority

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

End Authority Start Signature

Dated: February 17, 2021.

Debra Thomas,

Acting Regional Administrator, EPA Region 8.

End Signature End Supplemental Information

Footnotes

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 first submit a SIP revision to the EPA and gain EPA's approval of that revision.

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2.  72 FR 20586 (Apr. 25, 2007).

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3.  Nat. Res. Def. Council v. EPA, 706 F.3d 428, 437 (D.C. Cir. 2013) (NRDC).

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4.  In designated nonattainment areas where monitored data demonstrate that the NAAQS have been achieved, the EPA interprets the CAA to provide that some of its requirements as no longer applicable as long as air quality continues to meet the standard. This CAA interpretation is known as the Clean Data Policy. As relevant to PM2.5 areas, this policy is reflected in EPA regulations at 40 CFR 51.1015.

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5.  CAA Section 107(d)(3)(E).

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7.  See 80 FR 54237 (Sep. 9, 2015).

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8.  January 13, 2020 Logan NAA PM2.5 Redesignation Request Submittal; Section IX.A.28 Maintenance Plan; Appendix A.

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9.  See “State Implementation Plans; General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990,” 57 FR 13498, April 16, 1992.

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10.  See 83 FR 52983, October 19, 2018.

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11.  As defined in 40 CFR part 50, appendix N, section (1)(c).

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13.  The Preston monitor does not have a valid design value for the 2017-2019 three-year period because of an incomplete 2017 quarter 1 which cannot be substituted with quarter 1 data at the same monitor in 2018 or 2019 per 40 CFR part 50, appendix N, section 4.2(c)(i) because it has below 50% complete data for that quarter.

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14.  CAA sections 175A(b) and (d).

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15.  See January 13, 2020 State of Utah submittal for Logan PM2.5 Maintenance Plan; Figure IX.A.28.4, CAMx Photochemical Modeling Domain in Two-Way Nested Configuration.

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16.  “Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations,” EPA-454/B-17-002 (May 2017), available at https://www.epa.gov/​sites/​production/​files/​2017-07/​documents/​ei_​guidance_​may_​2017_​final_​rev.pdf .

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17.  January 13, 2020 Logan PM2.5 Redesignation Request/Maintenance Plan TSD, Section 4.e Meteorological Modeling.

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18.  Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze, EPA454/B-07-002 (Apr. 2007).

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19.  PM2.5 State Implementation Plan Meteorological Modeling; Prepared by Department of Atmospheric Sciences, University of Utah for UDAQ.

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20.  These values include additional emissions added to the CMPO MVEB from the safety margin. The safety margin is discussed further in Section D below. Units of Design Values are µg/m3. , while RRF's are dimensionless.

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22.  40 CFR 93.102(b) and 93.122(f); see also conformity rule preamble at 69 FR 40004, 40031-40036 (July 1, 2004).

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23.  “PM2.5 Re-entrained Road Dust—Utah Request for Deletion from PM2.5 Motor Vehicle Emissions Budget (MVEB): EPA Concurrence” dated July 20, 2011 (included in docket for this action).

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24.  57 FR 13498, April 16, 1992.

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27.  Section 110(k)(1) of the Act and 57 FR 13565, April 16, 1992.

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[FR Doc. 2021-03819 Filed 2-25-21; 8:45 am]

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