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Proposed Rule

Air Plan Approval; ID: Idaho Portion of the Logan UT-ID 2006 24-Hour PM2.5

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Environmental Protection Agency (EPA).


Proposed rule.


The Environmental Protection Agency (EPA) is proposing to approve Start Printed Page 55101revisions to the Idaho State Implementation Plan (SIP) submitted on July 31, 2018. Idaho's submission addresses specific Clean Air Act (CAA) requirements for the Idaho portion of the Logan, Utah-Idaho fine particulate matter (PM2.5) nonattainment area (Logan UT-ID area). The submission fulfills Idaho's commitment to submit Reasonable Further Progress and Quantitative Milestone attainment plan elements and updated Motor Vehicle Emissions Budgets to the EPA. If this proposed approval is finalized, the EPA's prior conditional approval will be removed and these elements will become fully approved.


Comments must be received on or before November 14, 2019.


Submit your comments, identified by Docket ID No. EPA-R10-OAR-2018-0597, at Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from The EPA may publish any comment received to its public docket. Do not electronically submit any information you consider to be Confidential Business Information (CBI) or other information the disclosure of which is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit​dockets/​commenting-epa-dockets.

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Matthew Jentgen, (206) 553-0340,

End Further Info End Preamble Start Supplemental Information


Throughout this document whenever “we,” “us,” or “our” is used, it is intended to refer to the EPA.

Table of Contents

I. Background

II. Analysis of the State's Submission

III. Proposed Action

IV. Statutory and Executive Order Reviews

I. Background

On November 13, 2009, the EPA designated a portion of Franklin County, Idaho nonattainment for the 2006 24-hour PM2.5 NAAQS (74 FR 58688). This designation, as part of the cross-state Logan, Utah-Idaho area, required Idaho to prepare and submit an attainment plan to meet current statutory and regulatory requirements.[1] On December 14, 2012, the Idaho Department of Environmental Quality (IDEQ) submitted an attainment plan for the Idaho portion of the Logan UT-ID area. The plan addressed specific required elements, including but not limited to the following elements: Emissions inventory, Reasonably Available Control Measures/Technology (RACM/RACT), attainment demonstration, contingency measures, and Motor Vehicle Emissions Budgets (MVEBs). The EPA approved the baseline emissions inventory on July 18, 2014 (79 FR 41904) and the control measures on March 25, 2014 (79 FR 16201). However, the EPA limited its approval of the submitted control measures [2] in light of the District of Columbia Circuit Court of Appeal's decision in NRDC v. EPA, holding that EPA erred in implementing the 1997 PM2.5 NAAQS pursuant only to the general implementation requirements of Title I, Part D, Subpart 1 of the CAA rather than also the requirements specific to PM10 in Title I, Part D, Subpart 4.[3] In response to the litigation, Idaho made a supplemental submission on December 24, 2014. The December 14, 2012 and December 24, 2014 submissions are hereinafter collectively referred to as the Idaho attainment plan.

The EPA responded to the Court's decision, in part, by retracting the March 2012 guidance on SIP requirements for meeting the 2006 24-hour PM2.5 standards [4] and promulgating the Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements (81 FR 58010, August 24, 2016). The 2016 PM2.5 SIP Requirements Rule clarified how states should meet the statutory SIP requirements under Subpart 1 and Subpart 4 that apply to areas designated as nonattainment for any PM2.5 NAAQS. Based on the requirements of Subparts 1 and 4 and the 2016 PM2.5 SIP Requirements Rule, on January 4, 2017, we approved Idaho's control measures as meeting RACM/RACT, disapproved contingency measures, and deferred action on the attainment demonstration, RFP, QM, and MVEB requirements (82 FR 729).

Following our January 4, 2017, action, in an April 25, 2017 letter, Idaho committed to make a SIP submission that would further address the RFP, QM, and MVEB requirements. Because Idaho committed to address these requirements within one year, in specific ways that the EPA considered appropriate, the EPA conditionally approved the RFP, QM, and MVEB elements of the Idaho attainment plan on August 8, 2017 (82 FR 37025). In that same action, we also finalized approval of the Idaho attainment demonstration and the 2014 MVEBs as early progress budgets. Based on quality-assured, quality-controlled data for the period 2015-2017 showing that the area attained the 2006 24-hour PM2.5 NAAQS, on October 19, 2018, the EPA finalized a determination of attainment by the attainment date and clean data determination for the Logan UT-ID area (83 FR 52983). Finalization of the clean data determination suspended the requirements for a nonattainment area to submit an RFP plan, MVEB for the attainment year, and other SIP requirements related to attainment of the 2006 PM2.5 NAAQS. By virtue of the EPA's October 19, 2018 clean data determination, the obligation to submit any attainment-related SIP revisions, including an RFP Plan, quantitative milestones, and an MVEB for the attainment year for the Logan, UT-ID area are not applicable so long as the area continues to attain the 2006 24-hour PM2.5 NAAQS. See 40 CFR 51.1015(a). As we stated in our October 19, 2018, action, the clean data determination does not preclude the state from submitting, nor the EPA from acting on, the suspended attainment plan elements. See 83 FR 52983, 52985.

II. Analysis of the State's Submission

On July 31, 2018, Idaho submitted a SIP revision to further address the RFP, QM, and MVEB elements that EPA conditionally approved on August 8, 2017 (Cache SIP Amendment or submission). The submission can be found in the docket for this action. An RFP plan or analysis must include four components, summarized as follows: (1) An implementation schedule for control measures on sources in the nonattainment area; (2) RFP projected emissions for each applicable quantitative milestone year; (3) an Start Printed Page 55102analysis that presents the schedule of control measures and estimated emissions changes to be achieved by each milestone year and (4) an analysis that demonstrates sufficient progress on an annual basis toward attainment between the applicable baseline year to the attainment year. See 40 CFR 51.1012. Idaho's submission addresses each of the four components required by 40 CFR 51.1012. First, the submission includes an implementation schedule for each of the three control measures. Second, the submission includes RFP projected emissions for each applicable quantitative milestone year. These measures, which were relied upon in the Idaho attainment plan, supported the attainment determination for the Logan UT-ID area based on 2015-2017 monitoring data.[5] Third, Idaho provided an analysis of emissions reductions achieved for each of the control measures.

The first control measure discussed in Idaho's submission, residential wood combustion (RWC) ordinances, were adopted within Franklin County and all six Idaho cities on the Idaho side of the Logan UT-ID area (Franklin, Preston, Weston, Dayton, Clifton, and Oxford). Key elements in the current RWC ordinances include mandatory burn bans issued when PM2.5 has reached or is forecasted to reach 75 on the Air Quality Index (AQI). This AQI value corresponds to a PM2.5 concentration of 23.5 micrograms per cubic meter (μg/m3) and aligns with the RWC ordinances applicable within Cache County on the Utah side of the Logan UT-ID area. All RWC ordinances effective in Franklin County prohibit both open burning and the use of specified devices when an air quality alert is issued. The ordinances also prohibit the installation of non-EPA-certified devices.

As stated in the submission, these Idaho cities and counties have implemented the ordinances and mandatory burn bans since 2012.[6] Therefore, we have determined the submission demonstrates full implementation of this control measure. Idaho estimated that maximum reductions for this measure are 0.06 tons per day (tpd) direct PM2.5, 0.009 tpd nitrogen oxides (NOX), and 0.078 tpd volatile organic compounds (VOC).[7]

Idaho also implemented three wood stove change-out programs on the Idaho side of the Logan UT-ID area. These programs were conducted in 2006-2007, 2011-2012, and 2013-2014. Accordingly, Idaho demonstrated in the submission that a total of 209 uncertified RWC devices have been changed-out since 2006. In addition, 39 stoves were removed and destroyed through Idaho's Alternative Energy Device tax deduction program. In total, 256 wood stoves have been changed out on the Idaho side of the Logan UT-ID area since 2006. As described in the submission (applying the appropriate temporal profile to convert to tons per day), Idaho stated these change-outs have led to reductions of 0.05 tpd direct PM2.5, 0.003 tpd NOX, and 0.13 tpd VOC.[8]

The final control measure implemented on the Idaho side of the Logan UT-ID area is road sanding agreements. Franklin County Road and Bridge, the City of Preston, and the Idaho Transportation Department (ITD) entered into road sanding agreements which were submitted to the EPA and approved into the Idaho SIP on March 25, 2014 (79 FR 16201). According to records submitted to Idaho and summarized in the submission, ITD used salt in 2014 (409 tons), 2015 (340 tons), and 2016 (109 tons) and did not use sand. Franklin County Road and Bridge historically used a 10:1 ratio of sand and salt; however, in the Idaho attainment plan, Franklin County committed to use a 4:1 ratio of sand and salt when anti-skid treatment is required. Franklin County also agreed to apply brine when temperatures are above 22°F, a measure that further reduces the amount of sand required by approximately 50%. The City of Preston now uses a 2:1 ratio of sand and salt at an average of 700 tons total per year.

Finally, in Section 4.5 of the Cache SIP Amendment, Idaho provided an analysis that demonstrates sufficient progress on an annual basis toward attainment between the applicable baseline year to the attainment year. The analysis demonstrates that Idaho achieved emissions reductions consistent with RFP. Idaho's RFP analysis is supported by EPA's October 19, 2018 determination of attainment (83 FR 52983). Therefore, we propose to approve the RFP element submitted by Idaho as part of its Moderate area plan for the Logan UT-ID area.

With respect to QMs, EPA regulations require that the attainment plan contain quantitative milestones to be achieved by the milestone dates that provide for objective evaluation of reasonable further progress toward timely attainment. See 40 CFR 51.1013. For areas designated nonattainment for the 2006 PM2.5 NAAQS, such as the Logan UT-ID area, quantitative milestones are required no later than 3 years after December 31, 2014 40 CFR 51.1013(a)(4). Thus, 2017 is the first year the Logan, UT-ID area must include quantitative milestones. The 2016 PM2.5 SIP Requirements Rule states that the quantitative milestones contained in the attainment plan for a Moderate nonattainment area should be constructed such that they can be tracked, quantified and/or measured adequately in order for a state to meet its milestone reporting obligations, which are due 90 days after a given milestone date.[9] The EPA suggested possible metrics that “support and demonstrate how the overall quantitative milestones identified for an area may be met, such as percent implementation of control strategies, percent compliance with implemented control measures, and adherence to a compliance schedule.” [10] This list was not exclusive or exhaustive but reflected the EPA's view that the purpose of the quantitative milestone requirement is to provide an objective way to determine whether the area is making the necessary progress towards attainment by the applicable attainment date, i.e., to verify that the separate RFP requirement is met.[11]

Idaho's submission includes a detailed implementation schedule, estimated emissions reductions, and 2017 QM reporting metrics for the control measures discussed above. For the wood combustion ordinances, Idaho included in the submission a summary of the wood stove and open burning curtailment days issued per year since 2012 as a means of demonstrating implementation of this measure. The objective measure to determine the progress of implementation of the wood stove change-out program is the total number of wood stove change-outs completed. For road sanding agreements, the objective metrics used to track progress are tons of sand and salt used and changes in the sand-salt ratio. On March 7, 2018, Idaho submitted a Quantitative Milestone Report to demonstrate that all emission reduction measures have been implemented, and Idaho has achieved milestones demonstrating progress toward attainment.[12] The EPA responded on September 7, 2018 stating Start Printed Page 55103the submittal adequately met the Quantitative Mileston reporting requirements.[13] Therefore, we propose to approve Idaho's QMs as meeting the requirements of the CAA and EPA's implementing regulations.

Lastly, with respect to MVEBs, an attainment plan must include in its RFP submission an inventory of on-road mobile source emissions in the nonattainment area for each milestone year.[14] The Idaho attainment plan projected 2014 emission budgets. On August 8, 2017, the EPA approved the submitted 2014 MVEBs as early progress budgets and conditionally approved Idaho's commitment to submit MVEBs for the 2015 attainment year (82 FR 37025). In the submission, Idaho modeled 2015 and 2017 on-road vehicle emissions. Growth in vehicle mile traveled (VMT) was estimated using automatic traffic recorder, and population growth was estimated using census data.

The revised MVEBs were determined for direct PM2.5, NOX, and VOC emissions, pollutants that contribute to on-road mobile source emissions of primary and secondary particulates in the area. Idaho noted that, although ammonia (NH3) contributes to secondary aerosol formation, the region is NH3 rich, so the minimal mobile source NH3 emissions (less than 0.12 tons per day) are not considered in MVEBs. In addition, although originally thought by the state to be a primary contributor to direct PM2.5 concentrations, Idaho determined, based on the MVEB analysis, that direct PM2.5 emissions from paved road dust are not considered significant (1% of total wintertime contributions) and therefore were not included in the MVEBs.

The MVEB is comprised of on-road mobile sources and vehicle emissions (exhaust, tire, and brake wear). The EPA's Motor Vehicle Emissions Simulator (MOVES) model was used to develop vehicle emissions estimates for the MVEB (Idaho used the most current version of MOVES available at the time, MOVES 2014a, for its analysis). The MVEB will apply when the EPA determines the budget is adequate for transportation conformity. According to the EPA's conformity rule, the emissions budget acts as a ceiling on emissions in the year for which it is defined or until a SIP revision modifies the budget. Based on the analysis, Idaho set the following emissions budgets for 2015, applicable to the Idaho side of the Logan UT-ID area: 0.033 tpd direct PM2.5, 0.676 tpd NOX, and 0.554 tpd VOC. In the submission, Idaho included a MVEB for the 2017 RFP year that sets the following emissions budgets: 0.029 tpd direct PM2.5, 0.544 tpd NOX, and 0.467 tpd VOC.

We find that Idaho has evaluated the appropriate pollutants in its MVEB analysis and included MVEBs for the appropriate milestone years. According to the EPA's conformity rule, ammonia is a pollutant that is not required to be included in a PM2.5 nonattainment area's MVEB unless it is determined to be a significant contributor to PM2.5 formation in the area (40 CFR 93.102(b)(2)(v)). Paved road dust can also be excluded from an area's MVEB for similar reasons (40 CFR 93.102(b)(3)). Neither IDEQ or the EPA Regional Administrator have made a finding that transportation-related emissions of ammonia or re-entrained paved road dust are a significant contributor to the PM2.5 nonattainment problem. Therefore, we propose to approve Idaho's MVEBs as meeting the requirements of the CAA and EPA's implementing regulations.

III. Proposed Action

Based on Idaho's submission and our evaluation discussed above, the EPA is proposing to approve the RFP and QM elements and revised MVEBs in the Cache SIP Amendment. If this proposed approval is finalized, the EPA's prior conditional approval will be removed and these elements will become fully approved.

IV. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this proposed action merely approves state law as meeting federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

  • Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, 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 it does not involve technical standards; and
  • Does not provide the EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where the EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

Start List of Subjects

List of Subjects in 40 CFR Part 52

  • Environmental protection
  • Air pollution control
  • Incorporation by reference
  • Intergovernmental relations
  • Lead
  • Nitrogen dioxide
  • Ozone
  • Particulate matter
  • Reporting and recordkeeping requirements
  • Sulfur oxides
  • Volatile organic compounds
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Authority: 42 U.S.C. 7401 et seq.

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Dated: October 2, 2019.

Chris Hladick,

Regional Administrator, Region 10.

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1.  See part D of title I of the Clean Air Act and the EPA's Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements (72 FR 20586, April 25, 2007).

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2.  The control measures were incorporated into the Idaho SIP, but the EPA did not make a determination that the control measures satisfy the requirement to adopt and implement RACM under CAA Sections 172(c) and 189(a)(1) and 40 CFR 51.1009.

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3.  NRDC v. EPA, 706 F.3d 428 (DC Cir. 2013).

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4.  Memorandum of March 2, 2012 (withdrawn June 6, 2013), from Stephen D. Page, Director, Office of Air Quality Planning and Standards, to the EPA Regional Air Directors, Region I-X, “Implementation Guidance for the 2006 24-Hour Fine Particle (PM2.5) National Ambient Air Quality Standards (NAAQS).”

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5.  Determination of Attainment by the Attainment Date and Clean Data Determination for the Logan, UT-ID area, October 19, 2018 (83 FR 52983).

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6.  Cache SIP Amendment, Section 4.2 and Appendix B.

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7.  Cache SIP Amendment, Section 4.1.

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8.  Cache SIP Amendment, Section 4.1.

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10.  2016 PM2.5 SIP Requirements Rule (81 FR 58010, 58064).

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12.  Idaho's March 7, 2018 Quantitative Milestone Report is included in the docket for this action.

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13.  The EPA's September 7, 2018, reply letter and supporting document are included in the docket for this action.

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[FR Doc. 2019-22438 Filed 10-11-19; 8:45 am]