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Approval and Promulgation of Air Quality Implementation Plans; State of Utah; Utah County--Trading of Motor Vehicle Emission Budgets for PM10 Transportation Conformity

American Government Special Collections Reference Desk

American Government

Approval and Promulgation of Air Quality Implementation Plans; State of Utah; Utah County--Trading of Motor Vehicle Emission Budgets for PM10 Transportation Conformity

Shaun L. McGrath
Environmental Protection Agency
May 18, 2015


[Federal Register Volume 80, Number 95 (Monday, May 18, 2015)]
[Rules and Regulations]
[Pages 28193-28201]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-11784]


=======================================================================
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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2015-0227; FRL-9927-68-Region 8]


Approval and Promulgation of Air Quality Implementation Plans; 
State of Utah; Utah County--Trading of Motor Vehicle Emission Budgets 
for PM10 Transportation Conformity

AGENCY: Environmental Protection Agency.

ACTION: Direct final rule.

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

SUMMARY: The Environmental Protection Agency (EPA) is taking direct 
final action to approve a State Implementation Plan (SIP) revision 
submitted by the State of Utah. On March 9, 2015, the Governor of Utah 
submitted a revision to the Utah SIP, adding a new rule regarding 
trading of motor vehicle emission budgets (MVEB) for Utah County. The 
rule allows trading from the motor vehicle emissions budget for primary 
particulate matter of 10 microns or less in diameter (PM10) 
to the motor vehicle emissions budget for nitrogen oxides 
(NOX), which is a PM10 precursor. The resulting 
motor vehicle emissions budgets for NOX and PM10 
may then be used to demonstrate transportation conformity with the SIP. 
The EPA is taking this action under section 110 of the Clean Air Act 
(CAA).

DATES: This rule is effective on July 17, 2015 without further notice, 
unless EPA receives adverse comment by June 17, 2015. If adverse 
comment is received, EPA will publish a timely withdrawal of the direct 
final rule in the Federal Register informing the public that the rule 
will not take effect.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2015-0227, by one of the following methods:
     http://www.regulations.gov. Follow the on-line 
instructions for submitting comments.
     Email: russ.tim@epa.gov
     Fax: (303) 312-6064 (please alert the individual listed in 
the FOR FURTHER INFORMATION CONTACT if you are faxing comments).
     Mail: Carl Daly, Director, Air Program, EPA, Region 8, 
Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129.
     Hand Delivery: Carl Daly, Director, Air Program, EPA, 
Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-
1129. Such deliveries are only accepted Monday through Friday, 8:00 
a.m. to 4:30 p.m., excluding federal holidays. Special arrangements 
should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-R08-OAR-
2015-0227. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an email comment directly to EPA, without 
going through http://www.regulations.gov, your email address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses. For additional instructions on submitting 
comments, go to Section I, General Information of the SUPPLEMENTARY 
INFORMATION section of this document.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly-available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the Air Program, EPA, 
Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-
1129. EPA requests that if at all possible, you contact the individual 
listed in the FOR FURTHER INFORMATION CONTACT section to view the hard 
copy of the docket. You may view the hard copy of the docket

[[Page 28194]]

Monday through Friday, 8:00 a.m. to 4:00 p.m., excluding Federal 
holidays.

FOR FURTHER INFORMATION CONTACT: Tim Russ, Air Program, EPA, Region 8, 
Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129, (303) 
312-6479, russ.tim@epa.gov.

SUPPLEMENTARY INFORMATION: 

Table of Contents

I. General Information
II. Background
III. What was the State's process?
IV. EPA's Evaluation of Utah Rule R307-311
V. EPA's Evaluation of the Technical Support Document for R307-311
VI. Consideration of Section 110(l) of the Clean Air Act
VII. Final Action
VIII. Incorporation by Reference
IX. Statutory and Executive Order Reviews

I. General Information

    1. Submitting CBI. Do not submit CBI to EPA through http://www.regulations.gov or email. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as 
CBI and then identify electronically within the disk or CD-ROM the 
specific information that is claimed as CBI. In addition to one 
complete version of the comment that includes information claimed as 
CBI, a copy of the comment that does not contain the information 
claimed as CBI must be submitted for inclusion in the public docket. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments, 
remember to:
    a. Identify the rulemaking by docket number and other identifying 
information (subject heading, Federal Register date and page number).
    b. Follow directions--The agency may ask you to respond to specific 
questions or organize comments by referencing a Code of Federal 
Regulations (CFR) part or section number.
    c. Explain why you agree or disagree; suggest alternatives and 
substitute language for your requested changes.
    d. Describe any assumptions and provide any technical information 
and/or data that you used.
    e. If you estimate potential costs or burdens, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    f. Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    g. Explain your views as clearly as possible, avoiding the use of 
profanity or personal threats.
    h. Make sure to submit your comments by the comment period deadline 
identified.

II. Background

    In this action, we are approving and soliciting public comment 
regarding the Governor's March 9, 2015, submittal of Utah's new Rule 
R307-311 for adoption into the Utah SIP. The rule will allow certain 
trading of MVEBs for the purposes of transportation conformity for 
PM10 for Utah County. Once approved by EPA, the Mountainland 
Association of Governments (MAG) will then be able to use the 
provisions of Rule R307-311 when MAG performs a transportation 
conformity determination for its Regional Transportation Plan (RTP) 
and/or Transportation Improvement Program (TIP).
    The above SIP action that was adopted by the Utah Air Quality Board 
(UAQB), and subsequently submitted to EPA by the Governor of Utah for 
approval, is discussed in greater detail in sections III, IV, and V 
below. We also discuss the state's associated technical support 
document (TSD), which gives technical information to support new Rule 
R307-311.

III. What was the State's process?

    Sections 110(a)(2) and 110(l) of the CAA requires that a state 
provide reasonable notice and public hearing before adopting a SIP 
revision and submitting it to us. More detailed requirements for notice 
and public hearing are set out in 40 CFR 51.102.
    On December 4, 2014 the UAQB proposed for public comment amendments 
to the Utah SIP for Utah Air Quality Rule R307-311; ``Utah County: 
Trading of Emission Budgets for Transportation Conformity.'' In 
addition on January 12, 2015, the Utah Division of Air Quality (UDAQ) 
made the proposed TSD available for public comment and extended the 
Rule R307-311 public comment period to February 12, 2015. EPA notes 
that included with the state's administrative documentation for this 
SIP and Rule revision was a letter memorandum, DAQ-010-15 dated 
February 19, 2015, from Bryce Bird, Director, UDAQ to the UAQB. This 
letter memorandum indicated that a public comment period was held from 
January 1, 2015 through February 12, 2015 regarding the proposed Rule 
R307-311 SIP revisions. The UDAQ February 19, 2015 letter memorandum 
noted that no public comments were received on the proposed rule R307-
311, but that EPA did comment on the TSD. UDAQ summarized and responded 
to EPA's comments in its February 19, 2015 letter memorandum to the 
UAQB. In addition, UDAQ noted that no public hearings were requested. 
In consideration of the February 19, 2015 UDAQ letter memorandum, the 
UAQB subsequently adopted the proposed Rule R307-311, and a revised 
TSD, on March 4, 2015. The SIP Rule revision became state effective on 
March 5, 2015 and was submitted by the Governor to EPA by a letter 
dated March 9, 2015. By a subsequent letter dated March 11, 2015, Bryce 
Bird, Director, UDAQ submitted the necessary administrative 
documentation that supported the Governor's submittal.
    We have evaluated Utah's March 9, 2015 SIP submittal and the March 
11, 2015 submitted administrative documentation and have determined 
that the state met the requirements for reasonable notice and public 
hearing under section 110(a)(2) of the CAA. By a letter dated March 24, 
2015, we advised the state that the SIP submittal was complete under 
section 110(k)(1)(B) of the Act, because the submittal met the minimum 
``completeness'' criteria found in 40 CFR part 51, Appendix V.

IV. EPA's Evaluation of Utah Rule R307-311

(a) Background and Purpose

    Transportation conformity is required by section 176 of the CAA to 
ensure that federally supported highway and transit project activities 
are consistent with (``conform to'') the purpose of a SIP. Conformity 
to the purpose of the SIP means that transportation activities will not 
cause new air quality violations, worsen existing violations, or delay 
timely attainment of the national ambient air quality standards 
(NAAQS). EPA's transportation conformity rule establishes the criteria 
and procedures for determining whether transportation activities 
conform to the state air quality plan.
    One key provision of EPA's transportation conformity rule (see 40 
CFR part 93, subpart A) requires a demonstration that emissions from 
the RTP and TIP are consistent with the MVEB in the applicable SIP (40 
CFR 93.118 and 93.124). The transportation conformity MVEB is defined 
as the level of on-road mobile source emissions relied upon in the SIP 
to attain or maintain compliance with the NAAQS in the nonattainment or 
maintenance area.
    In this particular instance, the NAAQS involved is PM10, 
the nonattainment area is Utah County, the

[[Page 28195]]

MVEBs involve direct emissions of PM10 and NOX, 
the latter as a precursor to the formation of PM10, and the 
applicable SIP is the EPA-approved Utah PM10 attainment 
plan, as updated on December 23, 2002 (67 FR 78181). The approved 
PM10 attainment plan contains (among other things) an 
attainment demonstration for Utah County that sets PM10 and 
NOX MVEBs.
    Transportation conformity is demonstrated when future year's 
projected on-road mobile source's emissions, for a particular pollutant 
or precursor, are estimated to be at or below the on-road motor 
vehicle's emissions budget for that pollutant or precursor in the 
applicable SIP. For the PM10 NAAQS for Utah County, 
conformity must be demonstrated separately for the PM10 and 
NOX MVEBs established in the Utah County PM10 
attainment demonstration. However, emissions can be traded between the 
PM10 and NOX budgets if there is an approved rule 
in the SIP that establishes appropriate mechanisms for such trades. See 
40 CFR 93.124(b).
    Currently, the Utah SIP does not contain an approved rule that 
establishes an appropriate mechanism for trading of emissions between 
the PM10 and NOX MVEBs for Utah County. The EPA 
notes, however, that we previously approved a Utah Rule (R307-310) that 
allows trading of emissions between the PM10 and 
NOX MVEBs for another PM10 nonattainment area in 
Utah, Salt Lake County. 67 FR 44065 (July 1, 2002). For Utah County, 
the state has developed a new Rule R307-311, very similar to that for 
Salt Lake County, which establishes an on-road mobile source emissions 
trading mechanism that; (1) involves only PM10 and 
NOX MVEBs from the PM10 attainment demonstration 
SIP, (2) allows trading in only one direction from the PM10 
budget to the NOX budget on a one-to-one basis, (3) applies 
only to transportation conformity determinations in Utah County in 
conjunction with the PM10 attainment demonstration SIP, and 
(4) is pursuant to 40 CFR part 93, subpart A.

(b) Utah Rule R307-311 Description

    An overview of all portions of the state's new Rule R307-311 is 
provided below:
    1. R307-311 is entitled ``Utah County: Trading of Emission Budgets 
for Transportation Conformity.''
    2. R307-311-1 ``Purpose.'' The stated purpose of this new rule is:
    This rule establishes the procedures that may be used to trade a 
portion of the primary PM10 budget when demonstrating that a 
transportation plan, transportation improvement program, or project 
conforms with the motor vehicle emissions budgets in the Utah County 
portion of Section IX, Part A of the State Implementation Plan, ``Fine 
Particulate Matter (PM10).
    3. R307-311-2. ``Definitions.'' This section provides applicable 
definitions:
    The definitions contained in 40 CFR 93.101, effective as of the 
date referenced in R307-101-3,\1\ are incorporated into this rule by 
reference. The following additional definitions apply to this rule.
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    \1\ R307-101-3 is approved into the Utah SIP and reflects a date 
of July 1, 2013 for incorporation by reference of federal rules.
---------------------------------------------------------------------------

    ``Budget'' means the motor vehicle emission projections used in the 
attainment demonstration in the Utah County portion of Section IX, Part 
A of the State Implementation Plan, ``Fine Particulate Matter 
(PM10).
    ``NOX'' means oxides of nitrogen.
    ``Primary PM10'' means PM10 that is emitted 
directly by a source. Primary PM10 does not include 
particulate matter that is formed when gaseous emissions undergo 
chemical reactions in the ambient air.
    ``Transportation Conformity'' means a demonstration that a 
transportation plan, transportation improvement program, or project 
conforms with the emissions budgets in a state implementation plan, as 
outlined in 40 CFR, Chapter 1, Part 93; \2\ Determining Conformity of 
Federal Actions to State or Federal Implementation Plans.
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    \2\ EPA notes this is applicable to projects not from a 
conforming RTP and TIP which must conform with the MVEBs. This 
clarification is only for those projects, and not projects from a 
conforming RTP and TIP. See 40 CFR 93.109(b) and 40 CFR 93.115(a).
---------------------------------------------------------------------------

    4. R307-311-3. ``Applicability''. This portion of the rule defines 
its applicability. EPA notes that this rule may only be applied to Utah 
County and only for PM10:
    (A) This rule applies to agencies responsible for demonstrating 
transportation conformity with the Utah County portion of Section IX, 
Part A of the State Implementation Plan, ``Fine Particulate Matter 
(PM10).
    (B) This rule does not apply to emission budgets from Section IX, 
Part C.6 of the State Implementation Plan, ``Carbon Monoxide 
Maintenance Provisions.
    5. R307-311-4. ``Trading Between Emission Budgets.'' This portion 
of the rule specifies the trading mechanism and provides the trading 
ratio of NOX and PM10. In our section V below, 
EPA evaluates the technical justification provided in the TSD for the 
trading ratio. In this section, we find that the rule language 
establishes an appropriate trading mechanism for the Utah County 
NOX and PM10 motor vehicle emission budgets:
    The agencies responsible for demonstrating transportation 
conformity are authorized to supplement the budget for NOX 
with a portion of the budget for primary PM10 for the 
purpose of demonstrating transportation conformity for NOX. 
The NOX budget shall be supplemented using the following 
procedures.
    (a) The metropolitan planning organization shall include the 
following information in the transportation conformity demonstration:
    (i) The budget for primary PM10 and NOX for 
each required year of the conformity demonstration, before trading 
allowed by this rule has been applied;
    (ii) The portion of the primary PM10 budget that will be 
used to supplement the NOX budget, specified in tons per day 
using a 1:1 ratio of primary PM10 to NOX, for 
each required year of the conformity demonstration;
    (iii) The remainder of the primary PM10 budget that will 
be used in the conformity demonstration for primary PM10, 
specified in tons per day for each required year of the conformity 
demonstration; and
    (iv) The budget for primary PM10 and NOX for 
each required year of the conformity demonstration after the trading 
allowed by this rule has been applied.
    (b) Transportation conformity for NOX shall be 
demonstrated using the NOX budget supplemented by a portion 
of the primary PM10 budget as described in (a)(ii). 
Transportation conformity for primary PM10 shall be 
demonstrated using the remainder of the primary PM10 budget 
described in (a)(iii).
    (c) The primary PM10 budget shall not be supplemented by 
using a portion of the NOX budget.

V. EPA's Evaluation of the Technical Support Document for R307-311

    The Governor's SIP revision submittal provided a TSD to support the 
new Rule R307-311 and address MVEB trading, as contemplated by 40 CFR 
93.124(b), for PM10 and NOX in Utah County.

a. Description

    PM10 is particulate matter with diameters smaller than 
10 micrometers. PM10 consists of solid and/or liquid 
particles of; (1) primary particles that are directly emitted 
particulate matter (PM) or PM that quickly condenses upon release, and 
(2) secondary particles which are PM that is formed in the atmosphere 
from gaseous

[[Page 28196]]

precursors. Important gaseous precursors to PM include sulfur dioxide 
(SO2) which converts to sulfate (SO4) particles, 
NOX which converts to nitrate (NO3) particles, 
volatile organic compounds (VOCs) some of which convert to secondary 
organic aerosols, and ammonia (NH3) which adds to the mass 
of sulfate PM and allows nitric acid to convert to PM10 in 
the form of ammonium nitrate.
    Currently in Utah County, the RTP and TIP must demonstrate 
conformity to the MVEBs for PM10 and NOX that 
were derived from the 2002 EPA-approved PM10 attainment 
demonstration SIP (see 67 FR 78181, December 23, 2002). Since the 
regulatory goal is to achieve and maintain attainment of the NAAQS and 
conformity related to total PM10, not individual components, 
it should not matter in the conformity analysis whether PM10 
consists of directly emitted (primary) PM10 or secondary 
nitrate PM10 formed in the atmosphere from precursor 
NOX gas emissions, provided the MVEBs for PM10 
and NOX are consistent with the SIP's demonstration of 
attainment. The state's TSD outlines the scientific rationale for why 
excess NOX motor vehicle emissions (above the NOX 
MVEB level) can be offset, on a 1 to 1 basis, with available motor 
vehicle PM10 emissions (below the PM10 MVEB 
level). The State's TSD explains why the provisions of Rule R307-311 
are considered conservative (i.e., protective of the environment) in 
that the Rule only allows a one-way direction trading of the MVEBs and 
a trading ratio of only 1 to 1.

b. What fraction of the NOX emissions in Utah County convert 
to PM10?

    The state's TSD describes how each ton of gaseous NOX 
that gets converted to PM10 creates more than a ton of 
PM10 because the molecular weight of ammonium nitrate 
PM10 is greater than the molecular weight of NOX 
gaseous emissions. Considering the ratio of the molecular weights of 
the NOX precursor gas and the resulting ammonium nitrate 
aerosol (PM10), the state notes that a ton of NOX 
that is converted from a gas to a particle can form as much as 1.74 
tons of PM10.
    However, not all NOX emissions are converted because it 
takes time to convert NOX to nitric acid (HNO3), 
which is the necessary gaseous precursor to ammonium nitrate 
PM10. These reactions generally occur at rates of 1 to 10 
percent per hour. It would take approximately at least 10 hours to 
fully convert to nitric acid. After this initial conversion, only a 
fraction of the gaseous nitric acid will condense as ammonium nitrate 
PM10, depending on equilibrium considerations. Finally, 
during the gas-to-particle conversion process, deposition will remove a 
significant amount of material. Throughout this process of 
NOX conversion to nitric acid, and then to PM10 
and deposition, an equivalent amount of directly emitted 
PM10 is having a much larger effect on the PM10 
concentration. Directly emitted PM10 has an effect on the 
ambient concentration immediately upon its release, while 
NOX emissions require hours to have an effect.
    From a historical perspective, the conversion of NOX to 
PM10 has been discussed at EPA since at least 1996. In our 
1996 proposed rule to revise the regulations for the Prevention of 
Significant Deterioration (PSD) and nonattainment New Source Review 
(NSR) programs, we discussed a proposed approach for interpollutant 
trading for PM10 offsets in the nonattainment NSR program:

    The conversion process may depend on several variables, 
including the availability of chemical reactants in the atmosphere 
for the conversion process, and the difference in mass between the 
PM10 precursor molecule and the PM10 particle 
that the precursor reacts to become. Another concern is that the 
rate of conversion of the precursor to PM10 may be so 
long that the precursor may not entirely convert to PM10 
within the same nonattainment area. Thus, there would be less 
counteracting effect and no net improvement to air quality in the 
area. Under the EPA's proposal, a source of a PM10 
precursor may offset its increased emissions with the same precursor 
type or PM10 (or a combination of the two). In this 
situation, a net improvement in air quality would be assured. At 
this point, however, the EPA is not proposing to allow offsetting 
among different types of PM10 precursors, or offsetting 
PM10 increases with reduction in PM10 
precursors, because the Agency does not now have a scientific basis 
to propose conversion factors. (61 FR 38305, July 23, 1996).

    These statements were cited in our 2002 proposed approval of the 
MVEB trading rule (R307-310) for Salt Lake County. 67 FR 21609 (May 1, 
2002).
    However, EPA has more recently issued guidance on interpollutant 
trading provisions for fine particulate matter (PM2.5) for 
offsets under the nonattainment NSR program. The guidance memorandum is 
entitled ``Revised Policy to Address Reconsideration of Interpollutant 
Trading Provisions for Fine Particles (PM2.5)'' and is dated 
July 21, 2011 (hereafter referred to as ``Revised 2011 Trading 
Policy''). The Revised 2011 Trading Policy states in part (page 3, 
fourth paragraph) that ``. . . states will be expected to develop 
separate PM2.5 precursor offset ratios that are demonstrated 
to be suitable for addressing the particular precursor's relationship 
with ambient PM2.5 concentrations for 24-hour averaging 
periods that are causing violations in that nonattainment area.'' And 
on page 4, first paragraph; ``. . . each ratio will need to be 
supported by modeling or other technical demonstration to show that 
such ratio is suitable for the particular PM2.5 
nonattainment area of concern . . .''
    Our Revised 2011 Trading Policy provides a general framework for 
such efforts, involving the following steps:
    1. Definition of the appropriate geographical area.
    2. Sensitivity runs with appropriate air quality models.
    3. Calculation of interpollutant ratios.
    4. Quality assurance of the results.
    To support Utah's rule R307-311, the UDAQ applied the above 
methodology to the Utah County 24-hour PM10 NAAQS 
nonattainment area. Although the Revised 2011 Trading Policy is 
specific to PM2.5 and nonattainment NSR offsets, and is 
nonbinding guidance, in this action we consider that the 
recommendations in the Revised 2011 Trading Policy provide a suitable 
approach for a technical demonstration that the trading ratio for Utah 
County for the PM10 and NOX MVEBs is appropriate 
under 40 CFR 93.124(b).
    The UDAQ states in the TSD that exceedances of the PM10 
24-hour NAAQS in Utah County are characterized by spikes in secondary 
aerosol formation under conditions of wintertime temperature inversions 
which prevent good atmospheric mixing and facilitate conversion of 
secondary PM10. The UDAQ also states that a high percentage 
of the PM10 monitored in Utah County, during winter episodes 
of elevated concentration, lies also within the PM2.5 
fraction. EPA also notes that the 2002 Utah County PM10 SIP 
revision identified both NOX and SO2 as 
precursors to the formation of PM10.
    The TSD for Rule R307-311 identifies that parts of Utah County (the 
valley regions, western area of the County) are also designated as 
nonattainment for the 2006 24-hour PM2.5 NAAQS (74 FR 58688, 
November 13, 2009). To meet the requirements set out in subparts 1 and 
4 of Part D, title I of the CAA, the UDAQ developed a moderate area 
attainment plan for Utah County that (among other things) contained a 
demonstration that attainment of the 24-hour PM2.5 standards 
by the applicable attainment date for moderate areas, December 31, 
2015, is impracticable (hereafter ``PM2.5 Impracticability 
Demonstration''). This

[[Page 28197]]

attainment plan was submitted by the Governor to EPA on December 16, 
2014. The air quality modeling for the PM2.5 
Impracticability Demonstration was conducted by UDAQ using the 
Community Multi-Scale Air Quality model (CMAQ). CMAQ is also capable of 
determining the relative importance of NOX and 
PM10 in contributing to PM10 nonattainment.
    The emission inventories that were developed by UDAQ for the Utah 
County PM2.5 Impracticability Demonstration included 
PM2.5, SO2, NOX, VOC, Ammonia and 
PM10.\3\ As PM10 was inventoried for the 
PM2.5 Impracticability Demonstration, this allowed CMAQ 
model sensitivity runs to be made for the purpose of evaluating and 
supporting the MVEB trading provisions in Rule R307-311. The UDAQ's 
methodology employed the CMAQ model, as developed for Utah County, with 
a substitution of PM10 emissions for PM2.5. The 
UDAQ also notes in the Rule R307-311 TSD that the CMAQ model was re-
validated with respect to PM10 emissions data from the 
appropriate episode period prior to making the sensitivity runs (refer 
to Appendix A of the TSD).
---------------------------------------------------------------------------

    \3\ We are not acting today on any portion of the state's 
December 16, 2014 submittal, including the PM2.5 
Impracticability Demonstration and the emission inventories.
---------------------------------------------------------------------------

    Having made these adjustments to the CMAQ model, UDAQ ran the model 
to generate a time-series plot (refer to Appendix A of the TSD). The 
UDAQ determined that the ratio of NOX to PM10 
equivalence was 5.702 to one. Since this ratio is considerably greater 
than 1:1, the UDAQ concluded that reducing primary PM10 is 
more beneficial than reducing NOX for improving Utah 
County's air quality with respect to PM10. The EPA has 
evaluated this additional sensitivity modeling information and has 
concluded that it provides an adequate technical demonstration to 
support the MVEB trading provisions in Rule R307-311. Based on the 
demonstration, we also conclude that Rule R307-311 establishes an 
appropriate trading ratio, and that under Rule R307-311, there will not 
be adverse impacts to the overall ambient 24-hour PM10 
concentrations within Utah County.
    With regard to ambient 24-hour PM10 concentrations 
within Utah County, we have also evaluated the current (state-
certified) 2011 through 2013 PM10 ambient air quality 
monitoring data for Utah County in EPA's Air Quality System (AQS), 
EPA's repository for the Nation's ambient air quality data. EPA's 
guidance for the calculation of 24-hour PM10 design value 
concentrations provide four techniques.\4\ Our guidance's ``Table 
Lookup'' method shows a 2011 through 2013 PM10 design value 
concentration as 149[mu]m\3\ at the North Provo monitor and 124[mu]m\3\ 
at the Lindon monitor. These values, however, contain certain data 
quality issues such as missing days of monitoring data and zero reading 
days. We believe that if the statistical method from our guidance, 
``Using the empirical frequency distribution of several years of the 
data (graphical estimation),'' is used, in this particular case it 
provides a more accurate representation of the monitoring data.\5\ When 
using this statistical/graphic approach, the North Provo monitor then 
has a 2011 through 2013 PM10 design value concentration of 
133.5 [micro]m\3\ and the Lindon monitor has a 2011 through 2013 design 
value concentration of 118.7 [micro]m\3\. However, EPA notes that 
regardless of the methodology used, Utah County continues to 
demonstrate attainment of the 24-hour PM10 NAAQS.
---------------------------------------------------------------------------

    \4\ PM10 SIP Development Guideline, EPA-450/2-86-001, 
June 1987, section 6.3; pages 6-3 through 6-8. The cited portions of 
this guidance are available in the docket for this action; the 
entire document is available online at http://www.epa.gov/ttn/caaa/t1/memoranda/pm10sip_dev_guide.pdf.
    \5\ Memorandum to File entitled ``Utah PM10 24-hour 
Design Concentrations,'' Richard M. Payton, USEPA Region 8, dated 
April 22, 2015.
---------------------------------------------------------------------------

c. Impact of the PM10 and NOX MVEB Trading Rule on Other Pollutants; 
EPA's Evaluation of Utah's Information Regarding the Provisions of 
Section 110(1) of the Clean Air Act

    Section 110(1) of the CAA states that a SIP revision cannot be 
approved if the revision would interfere with any applicable 
requirement concerning attainment and reasonable further progress 
towards attainment of a NAAQS or any other applicable requirement of 
the CAA. EPA's evaluation above shows that this SIP revision will not 
interfere with attainment of the PM10 NAAQS.
    In addition to being a designated nonattainment area for 
PM10, Utah County is also designated as nonattainment for 
the 2006 24-hour PM2.5 NAAQS. The city of Provo, in Utah 
County, is designated as an attainment/maintenance area for carbon 
monoxide (CO). These criteria pollutants, along with the 2008 8-hour 
ozone NAAQS and the 1-hour nitrogen dioxide (NO2) NAAQS, 
were evaluated by the state in the TSD for potential collateral impacts 
from the implementation of the provisions of Rule R307-311.
1. PM2.5
    As discussed above, part of Utah County (the western portion) was 
designated by EPA as nonattainment for the 2006 24-hour 
PM2.5 NAAQS (74 FR 58688, November 13, 2009), and on 
December 16, 2014, the state submitted an attainment plan containing, 
among other things, the PM2.5 Impracticability 
Demonstration. As with PM10 (described above), UDAQ 
performed sensitivity runs using the CMAQ modeling information that was 
developed for the PM2.5 Impracticability Demonstration. This 
modeling exercise was performed in order to determine an equivalence 
ratio between NOX and PM2.5. The resulting ratio 
of NOX to PM2.5 was determined by the UDAQ to be 
13.09 to 1.0. Similar to the result for PM10, the ratio is 
greater than one to one, and illustrates that reducing primary 
PM2.5 is more beneficial than reducing the same quantity of 
NOX.
    However, Rule R307-311 provides for reductions in PM10, 
and generally speaking, a reduction in PM10 is not 
necessarily a reduction in PM2.5. So that the above 
PM2.5 to NOX ratio could support a determination 
that Rule R307-311 would not have an adverse impact on overall 
PM2.5 concentrations in Utah County, the UDAQ considered the 
physical make-up of PM10 emissions from on-road mobile 
sources in Utah County. The following table, presenting information 
from the TSD, considers PM emissions as they were inventoried for 
calendar year 2015 in the PM2.5 Impracticability 
Demonstration for the Utah County PM2.5 nonattainment area:

                              Table 1--Utah County; On-Road Mobile Source Emissions
                                            [In tons per day in 2015]
----------------------------------------------------------------------------------------------------------------
                                                                       PM10            PM2.5          %PM2.5
----------------------------------------------------------------------------------------------------------------
Road Dust.......................................................            3.95            0.99            25.1

[[Page 28198]]

 
Direct PM.......................................................            1.84            1.38            75.0
                                                                 -----------------------------------------------
    Total.......................................................            5.79            2.37            40.9
----------------------------------------------------------------------------------------------------------------

    As derived from the state's information and as presented in Table 1 
above, for every ton of PM10 emissions due to on-road mobile 
sources, 0.409 tons would be composed of PM2.5. The 
provisions of Rule R307-311 would allow a one-ton increase in 
NOX emissions that would be offset by a one-ton decrease in 
the PM10 emissions. Based on the information in the above 
table, the state concluded that a one-ton increase in NOX 
emissions would be offset by a 0.409-ton decrease in PM2.5 
emissions. To illustrate, using the 1:0.409 ratio and the equivalence 
ratio of 13.09:1 for NOX to PM2.5, a 13 ton 
increase in NOX emissions would equal a 1 ton increase of 
PM2.5 emissions. However, applying the 1 to 1 trading ratio 
with PM10 would then require a 13 ton PM10 
emissions decrease which is a 5.3 ton (13 x 0.409) PM2.5 
emissions decrease. This example results in a net 4.3 ton decrease in 
PM2.5 emissions.
    Based on this 1:0.409 ratio and the equivalence ratio of 13.09:1 
for NOX to PM2.5, the EPA can, therefore, agree 
with the state and conclude that Rule R307-311, with its requirements 
to allow the trading of the PM10 budget to the 
NOX budget in one direction only at a ratio of 1:1, would 
not have an adverse impact on overall ambient 24-hour PM2.5 
concentrations within Utah County.
    The EPA notes that additional supporting information was provided 
in the PM2.5 Impracticability Demonstration as it included 
an emission inventory of NOX emissions for calendar year 
2015. The PM2.5 Impracticability Demonstration notes that 
on-road mobile sources in Utah County are expected to account for 21.48 
tons per winter weekday in 2015. The on-road mobile sources emissions 
were calculated using EPA's Motor Vehicle Emission Simulator (MOVES) 
model and the MOVES2010a version. This estimate is greater than the 
combined sum of the 2020 MVEBs for both PM10 and 
NOX contained in the EPA-approved 2002 SIP revision. To 
demonstrate, even if the entire PM10 MVEB was traded to 
increase the NOX MVEB as a result of the application of Rule 
R307-311, the resulting total NOX emissions would still be 
less than the 2015 estimated NOX emissions contained in the 
PM2.5 Impracticability Demonstration.
2. Carbon Monoxide (CO)
    As noted previously, the Provo-Orem area is a CO attainment/
maintenance area (70 FR 66264, November 2, 2005). EPA notes that 
NOX emissions do not act as a precursor to carbon monoxide; 
therefore, EPA has concluded that the application of the provisions of 
R307-311 will not impact the Provo-Orem CO maintenance plan or 
attainment of the CO NAAQS. The state notes in the Rule R307-311 TSD 
that CO maintenance plan has its own CO MVEB which has been set at a 
level demonstrated to keep the Provo-Orem area in attainment with the 
CO standard. The provisions of Rule R307-311 do not change the 
maintenance plan's CO MVEB.
    For purposes of completeness, the state provided recent CO ambient 
air quality monitoring data in the Rule R307-311 TSD. These data have 
been excerpted by EPA and are provided in the table below:

                                 Table 2--CO 1-Hour and CO 8-Hour Design Values
----------------------------------------------------------------------------------------------------------------
                   Year                       Annual CO NAAQS  (1-hour, 35 ppm)        8-hour CO NAAQS (9 ppm)
----------------------------------------------------------------------------------------------------------------
Monitor location:                          North Provo:                             North Provo:
    2011.................................     3.2 ppm.............................     2.1 ppm
    2012.................................     2.8 ppm.............................     1.9 ppm
    2013.................................     2.9 ppm.............................     2.0 ppm
    Preliminary 2014.....................     2.8 ppm.............................     1.9 ppm
----------------------------------------------------------------------------------------------------------------

    As can be seen in Table 2 above, the Provo area continues to 
demonstrate compliance with both the CO Annual and CO 8-hour NAAQS.
3. Ozone
    The EPA notes that NOX emissions are a precursor to the 
formation of ground level ozone, PM2.5, and PM10. 
With regard to ozone, we also note that Utah County has never been 
designated as nonattainment for any applicable ozone NAAQS. The 
current, applicable ozone NAAQS is the 2008 8-hour ozone NAAQS and Utah 
County was designated by EPA as unclassifiable/attainment for that 
NAAQS (77 FR 30088, May 21, 2012). Thus, the state has not had to 
develop an ozone attainment plan or maintenance plan for Utah County.
    To assess the potential impacts to Utah County's continued 
attainment of the 2008 8-hour ozone NAAQS, EPA considered ozone ambient 
air quality monitoring data for Utah County and predicted future-year 
NOX emission reductions from motor vehicles.
    The state provided recent ozone air quality monitoring data in the 
Rule R307-311 TSD. EPA has excerpted that information from the TSD and 
presents those data in Table 3 below:

[[Page 28199]]



                                                        Table 3--8-Hour Ozone Design Values (DV)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 8-hour ozone DV (NAAQS = 75                                 8-hour ozone DV (NAAQS = 75
              Year                      Monitor location                    ppb)                    Monitor location                    ppb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011...........................  North Provo..................  67.7 ppb....................  Spanish Fork................  68.0 ppb
2012...........................  North Provo..................  70.7 ppb....................  Spanish Fork................  70.3 ppb
2013...........................  North Provo..................  73.0 ppb....................  Spanish Fork................  70.3 ppb
2014 (Preliminary).............  North Provo..................  73.0 ppb....................  Spanish Fork................  71.7 ppb
--------------------------------------------------------------------------------------------------------------------------------------------------------

    As can be seen in Table 3 above, Utah County continues to 
demonstrate compliance with 2008 8-hour ozone NAAQS.
    The provisions of Rule R307-311 would allow for an increase in the 
Utah County PM10 SIP's NOX MVEB. However, EPA 
believes that regardless of this potential increase in the 
NOX MVEB, overall future NOX emissions from 
mobile sources will significantly decrease not only in Utah County, but 
in the nation as a whole. On April 28, 2014, we published a final rule 
adopting new Tier 3 emission standards and fuel requirements for motor 
vehicles and for motor vehicle fuels (79 FR 23414).
    Our April 28, 2014 final rule included new Tier 3 emission 
standards to reduce exhaust and evaporative emissions from light-duty 
vehicles, light-duty trucks, and heavy-duty vehicles up to 14,000 
pounds Gross Vehicle Weight Rating. In addition, the final rule 
specified corresponding changes to in-use fuel requirements. The motor 
vehicle tailpipe standards include different phase-in schedules that 
vary by vehicle class, but generally phase-in between model years 2017 
to 2021 for light duty vehicles and up to 2025 for heavy duty vehicles. 
The vehicle emission standards combined with the reduction of gasoline 
sulfur content, which allows both current and new vehicle emission 
control systems to function at a higher pollutant removal efficiently, 
will significantly reduce motor vehicle emissions of NOX, 
VOCs, direct PM2.5, CO and air toxics. Compared to current 
vehicle and fuel standards, the non-methane organic gases (NMOG) and 
NOX, presented as NMOG+NOX, Tier 3 tailpipe 
standards for light-duty vehicles are estimated to show an 
approximately 80% reduction from today's fleet average. As both 
NOX and VOCs contribute to the formation of ground level 
ozone and secondary PM2.5, the EPA notes that these vehicle 
emission reductions will have a positive impact on all areas of the 
nation including Utah County. Additionally, we expect to see associated 
downward trends of CO, ozone, PM2.5 and PM10 
concentrations that will reflect the implementation of these fuel/
vehicle emission improvements. Based on these expected reductions in 
motor vehicle emissions of NOX, along with the monitoring 
data showing that Utah County is currently attaining the 2008 ozone 
NAAQS, we conclude that Rule R307-311 will not interfere with 
attainment of the ozone NAAQS.
4. NO2
    The EPA notes that NOX emissions, which contain 
NO2, are a precursor to the formation of ground level ozone, 
PM2.5, and PM10. We also note that Utah County 
was designated as unclassifiable/attainment for the new, more 
stringent, 2010 1-hour NO2 NAAQS (77 FR 9532, February 17, 
2012).
    To assess the potential impacts to Utah County's continued 
attainment of the 2010 1-hour NO2 NAAQS, as that version of 
the NO2 NAAQS is more constraining, EPA considered 
NO2 ambient air quality monitoring data for Utah County. The 
state provided recent NO2 air quality monitoring data in the 
Rule R307-311 TSD. EPA has excerpted that information from the TSD and 
presents those data in Table 4 below:

                    Table 4--NO2 1-Hour Design Values
------------------------------------------------------------------------
                                              NO2 NAAQS  (DV 1-hour 100
                   Year                                 ppb)
------------------------------------------------------------------------
Monitor location:                           North Provo:
  2011....................................     54.7 ppb
  2012....................................     58.0 ppb
  2013....................................     66.3 ppb
  Preliminary 2014........................     68.3 ppb
------------------------------------------------------------------------

    As can be seen in Table 4 above, Utah County continues to 
demonstrate compliance with 2010 1-hour NO2 NAAQS with 
values well below the level of the NAAQS. We, therefore, conclude that 
Rule R307-311 will not interfere with attainment of the 1-hour 
NO2 NAAQS.

d. Conclusion

    On the basis of the above EPA analyses, we have concluded that 
using a portion of the Utah County PM10 SIP's 
PM10 MVEB to offset or compensate for excess on-road mobile 
sources NOX emissions, on a one-to-one basis and in one 
direction only, continues to demonstrate attainment of the 
PM10 NAAQS and is conservative and justifiable. In addition, 
based on the information in the Rule R307-311 TSD, and as supplemented 
by information prepared by EPA, we have concluded that with the 
implementation of the provisions in Rule R307-311 there will not be 
adverse effects to the CO, PM2.5, 8-hour ozone, and 
NO2 1-hour NAAQS. These statements are with respect to the 
implementation of the provisions of Rule R307-311 by MAG when MAG 
performs a transportation conformity determination for its RTP and/or 
TIP.

VI. Consideration of Section 110(l) of the Clean Air Act

    Section 110(l) of the CAA states that a SIP revision cannot be 
approved if the revision would interfere with any applicable 
requirement concerning attainment and reasonable further progress 
towards attainment of a NAAQS or any other applicable requirement of 
the CAA. In view of the state's rule language for its new Rule R307-
311, our analyses presented above in section ``V. EPA's Evaluation of 
the Technical Support Document for R307-311'' with respect to 
PM10, PM2.5, ozone and NO2, and the 
fact that NOX has less impact on a per ton basis than 
primary PM10 emissions in Utah County, we have concluded 
there will be a net benefit on ambient air concentrations of 
PM10 when excess NOX emissions are offset on a 
one to one basis. Therefore, implementation of the provisions of Rule 
R307-311 will allow the continued demonstration of attainment of the 
PM10 NAAQS in Utah County and is conservative and 
justifiable. We have also concluded there will be no adverse impact on 
any other NAAQS or applicable requirement of the CAA. Therefore, our 
approval of the State's Rule R307-311 is consistent with section 110(l) 
of the CAA.

VII. Final Action

    The EPA is publishing this rule without prior proposal because the 
Agency views the Governor of Utah's March 9, 2015 submitted SIP 
revisions for Utah's Rule R307-311 and the Rule's associated TSD as a 
noncontroversial amendment and anticipates no adverse

[[Page 28200]]

comments. However, in the Proposed Rules section of today's Federal 
Register publication, EPA is publishing a separate document that will 
serve as the proposal to approve the SIP revision if adverse comments 
are filed. This rule will be effective July 17, 2015 without further 
notice unless the Agency receives adverse comments by June 17, 2015. If 
the EPA receives adverse comments, the EPA will publish a timely 
withdrawal in the Federal Register informing the public that the rule 
will not take effect. The EPA will address all public comments in a 
subsequent final rule based on the proposed rule. The EPA will not 
institute a second comment period on this action. Any parties 
interested in commenting must do so at this time. Please note that if 
the EPA receives adverse comment on an amendment, paragraph, or section 
of this rule and if that provision may be severed from the remainder of 
the rule, the EPA may adopt as final those provisions of the rule that 
are not the subject of an adverse comment.

VIII. Incorporation by Reference

    In this rule, the EPA is finalizing regulatory text that includes 
incorporation by reference. In accordance with requirements of 1 CFR 
51.5, the EPA is finalizing the incorporation by reference of the Utah 
SIP materials and rules described in the amendments to 40 CFR part 52 
set forth below. The EPA has made, and will continue to make, these 
documents generally available electronically through 
www.regulations.gov and/or in hard copy at the appropriate EPA office 
(see the ADDRESSES section of this rule's preamble for more 
information).

IX. Statutory and Executive Order Reviews

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is not a ``significant regulatory action'' and therefore is not 
subject to review by the Office of Management and Budget. For this 
reason, this action is also not subject to Executive Order 13211, 
``Actions Concerning Regulations That Significantly Affect Energy 
Supply, Distribution, or Use'' (66 FR 28355, May 22, 2001). This action 
merely approves state law as meeting Federal requirements and imposes 
no additional requirements beyond those imposed by state law. 
Accordingly, the Administrator certifies that this rule will not have a 
significant economic impact on a substantial number of small entities 
under the Regulatory Flexibility Act (5 U.S.C. 601 et seq). Because 
this rule approves pre-existing requirements under state law and does 
not impose any additional enforceable duty beyond that required by 
state law, it 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).
    The SIP is not approved to apply on any Indian reservation land or 
in any other area where EPA or an Indian tribe has demonstrated that a 
tribe has jurisdiction. In those areas of Indian country, the 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). This action also 
does not have Federalism implications because it does not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government, as 
specified in Executive Order 13132 (64 FR 43255, August 10, 1999). This 
action merely approves a state rule implementing a Federal standard, 
and does not alter the relationship or the distribution of power and 
responsibilities established in the Clean Air Act. This rule also is 
not subject to Executive Order 13045 ``Protection of Children from 
Environmental Health Risks and Safety Risks'' (62 FR 19885, April 23, 
1997), because it approves a state rule implementing a Federal 
standard.
    In reviewing SIP submissions, EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. In 
this context, in the absence of a prior existing requirement for the 
state to use voluntary consensus standards (VCS), EPA has no authority 
to disapprove a SIP submission for failure to use VCS. It would thus be 
inconsistent with applicable law for EPA, when it reviews a SIP 
submission; to use VCS in place of a SIP submission that otherwise 
satisfies the provisions of the Clean Air Act. Thus, the requirements 
of section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (15 U.S.C. 272 note) do not apply. This rule does not 
impose an information collection burden under the provisions of the 
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq).
    The Congressional Review Act, 5 U.S.C. 801 et seq, as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).
    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by July 17, 2015. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this action for the purposes of 
judicial review nor does it extend the time within which a petition for 
judicial review may be filed, and shall not postpone the effectiveness 
of such rule or action. Parties with objections to this direct final 
rule are encouraged to file a comment in response to the parallel 
notice of proposed rulemaking for this action published in the proposed 
rules section of today's Federal Register, rather than file an 
immediate petition for judicial review of this direct final rule, so 
that EPA can withdraw this direct final rule and address the comment in 
the proposed rulemaking. This action may not be challenged later in 
proceedings to enforce its requirements. (See CAA section 307(b)(2).)

List of Subjects in 40 CFR Part 52

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

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

    Dated: May 1, 2015.
Shaun L. McGrath,
Regional Administrator, Region 8.

    40 CFR part 52 is amended to read as follows:

PART 52 [AMENDED]

0
1. The authority citation for Part 52 continues to read as follows:

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

Subpart TT--Utah

0
2. Section 52.2320 is amended by adding paragraph (c)(79) to read as 
follows:

[[Page 28201]]

Sec.  52.2320  Identification of plan.

* * * * *
    (c) * * *
    (79) Revisions to the Utah State Implementation Plan involving Utah 
Rule R307-311; Utah County: Trading of Emission Budgets for 
Transportation Conformity. The Utah Air Quality Board adopted this SIP 
revision on March 4, 2015, it became state effective on March 5, 2015, 
and was submitted by the Governor to EPA by a letter dated March 9, 
2015.
    (i) Incorporation by reference.
    (A) Utah Rules R307, Environmental Quality, Air Quality, R307-311, 
Utah County: Trading of Emission Budgets for Transportation Conformity. 
Effective March 5, 2015, as proposed in the Utah State Bulletin on 
January 1, 2015 and published on April 1, 2015 as effective.

[FR Doc. 2015-11784 Filed 5-15-15; 8:45 am]
 BILLING CODE 6560-50-P

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