[Federal Register Volume 83, Number 86 (Thursday, May 3, 2018)]
[Proposed Rules]
[Pages 19483-19495]
[FR Doc No: 2018-09313]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2016-0476; FRL-9977-01-Region 6]

Approval and Promulgation of Implementation Plans; Texas;
Attainment Demonstration for the Dallas/Fort Worth 2008 Ozone
Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: Pursuant to the Federal Clean Air Act (CAA or the Act), the
Environmental Protection Agency (EPA) is proposing to approve the ozone
attainment demonstration State Implementation Plan (SIP) revisions for
the Dallas/Fort Worth (DFW) moderate ozone nonattainment area under the
2008 ozone National Ambient Air Quality Standard (NAAQS) submitted by
the State of Texas (the State). Specifically, EPA is proposing approval
of the attainment demonstration, a reasonably available control
measures (RACM) analysis, the contingency measures plan in the event of
failure to attain the NAAQS by the applicable attainment date, and the
associated Motor Vehicle Emissions Budgets (MVEBs) for 2017, which is
the attainment year for the area.

DATES: Written comments must be received on or before June 4, 2018.

ADDRESSES: Submit your comments, identified by Docket No. EPA-R06-OAR-
2016-0476, at http://www.regulations.gov or via email to
[email protected]. Follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
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, please contact Robert M. Todd, 214-665-
2156, [email protected]. For 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: The index to the docket for this action is available
electronically at www.regulations.gov and in hard copy at the EPA
Region 6, 1445 Ross Avenue, Suite 700, Dallas, Texas. While all
documents in the docket are listed in the index, some information may
be publicly available only at the hard copy location (e.g., copyrighted
material), and some may not be publicly available at either location
(e.g., CBI).

FOR FURTHER INFORMATION CONTACT: Robert M. Todd,<PHONE_NUMBER>,
[email protected]. To inspect the hard copy materials, please
schedule an appointment with Mr. Todd or Mr. Bill Deese at 214-665-
7253.

SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' means the EPA.

Table of Contents

I. Background
II. The EPA's Evaluation
    A. Review of Eight-Hour Attainment Demonstration Modeling and
Weight of Evidence
    1. What is a photochemical grid model?
    2. Model Selection
    3. What episode did Texas choose to model?
    4. How well did the model perform?
    5. Once the base case is determined to be acceptable, how is the
modeling used for the attainment demonstration?

    6. What did the results of TCEQ's 2017 future year attainment
demonstration modeling show?
    7. What are EPA's conclusions of the modeling demonstration?
    8. Weight of Evidence (WOE)
    a. Background
    b. What additional modeling-based evidence did texas provide?
    c. Other Non-Modeling WOE
    d. Other WOE Items From Texas Not Currently Quantified With
Modeling: Additional Programs/Reductions, etc.
    9. Is the 8-hour attainment demonstration approvable?
    B. Review of Other Plan Requirements
    1. Emissions Inventory (EI)
    2. Nonattainment new source review (NNSR)
    3. Motor vehicle inspection and maintenance (I/M)
    4. Reasonable further progress (RFP)
    5. Reasonably available control technology (RACT)
    6. Reasonably available control measures (RACM)
    7. Attainment motor vehicle emission budgets (MVEBs)
    8. Contingency measures plan
    C. CAA Section 110(l) Analysis
III. Proposed Action
IV. Statutory and Executive Order Reviews

I. Background

    In 2008 we revised the 8-hour ozone primary and secondary NAAQS to
a level of 0.075 parts per million (ppm) or 75 parts per billion (ppb)
to provide increased protection of public health and the environment
(73 FR 16436, March 27, 2008). The 2008 ozone NAAQS revised the 1997 8-
hour ozone NAAQS of 0.08 ppm. The DFW area was classified as a
``Moderate'' ozone nonattainment area (NAA) for the 2008 ozone NAAQS
and initially given an attainment date of no later than December 31,
2018 (77 FR 30088 and 77 FR 30160, May 21, 2012). The DFW Moderate
ozone NAA for the 2008 ozone standard consists of Collin, Dallas,
Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant and Wise
counties (DFW NAA).
    On December 23, 2014, the DC Circuit Court of Appeals issued a
decision rejecting, among other things, our attainment deadlines for
the 2008 ozone nonattainment areas, finding that we did not have
statutory authority under the CAA to extend those deadlines to the end
of the calendar year. NRDC v. EPA, 777 F.3d 456, 464-69 (DC Cir. 2014).
Consistent with the Court's decision to vacate that portion of the
rule, we modified the attainment deadlines for all nonattainment areas
for the 2008 ozone NAAQS, and set the attainment deadline for all 2008
Moderate ozone nonattainment areas, including the DFW NAA as July 20,
2018 (80 FR 12264, March 6, 2015).
    On July 10, 2015, Texas submitted a SIP revision for the DFW NAA
based on an attainment date of December 31, 2018. Because that date was
vacated by the Court, Texas had to further revise its SIP to address an
attainment date of July 20, 2018 which it submitted on August 5,
2016.\1\ The portion of the July 10, 2015 SIP submittal that was not
impacted by the Court's decision was the contingency measures plan
portion as Texas was able to address the July 20, 2018 attainment
deadline for this portion of the plan. Because the State revised and
replaced the other portions of the 2015 SIP that were impacted by the
Court's decision, with the August 5, 2016 submittal, the remainder of
the 2015 submittal is superseded by the August 5, 2016 submittal. See
the docket for copies of these submittals.
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    \1\ In the DFW AD SIP revision for the 2008 eight-hour ozone
NAAQS submitted to the EPA on July 10, 2015, a commitment was made
to address the D.C. Circuit's decision that changed the attainment
deadlines for the 2008 eight-hour ozone NAAQS to a July 20, 2018
attainment date and a 2017 attainment year. The 2016 SIP revision
includes a new photochemical modeling analysis, a weight of evidence
analysis, and a reasonably available control measures analysis that
reflect the 2017 attainment year.
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    The August 5, 2016 submittal is designed to demonstrate attainment
of the 2008 ozone NAAQS by the attainment date of July 20, 2018 and
relies, in part, on a variety of controls on minor and major stationary
sources and controls on mobile source emissions, achieved through a
combination of Federal, State and Local measures. These measures are
projected to reduce emissions of NOX and VOC in the DFW
NAA.\2\ The measures that have been relied on in this demonstration
have been approved in prior Federal Register (FR) actions, as noted
below. The Texas Commission on Environmental Quality (TCEQ or the
State) used photochemical modeling and other corroborative evidence to
predict the improvement in ozone levels that will occur due to these
controls while accounting for growth in the DFW NAA.
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    \2\ NOX and VOC are precursors to ozone formation.
Additional information on ozone formation and the NAAQS is provided
on the EPA website: https://www.epa.gov/ozone-pollution. Additional
information on the history of the Texas and DFW SIPs is provided on
the TCEQ website: https://www.tceq.texas.gov/airquality/sip and in
the proposed rule to address the DFW attainment demonstration under
the 1997 ozone NAAQS, provided in docket ID EPA-R06-OAR-2007-0524.
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    Per the requirements in our final rule titled ``Implementation of
the 2008 National Ambient Air Quality Standards for Ozone: State
Implementation Plan Requirements; Final Rule,'' 80 FR 12264 (March 6,
2015), SIP Requirements Rule (SRR), an area classified as Moderate
under 40 CFR 51.1103(a)--in this case is the DFW NAA--shall be subject
to the requirements applicable for that classification under CAA
section 182(b).\3\ For each nonattainment area, under 40 CFR 51.1108,
the state must provide for implementation of all control measures
needed for attainment no later than the beginning of the attainment
year ozone season. Consistent with CAA section 182(b), each state in
which a Moderate Area is located shall, with respect to the Moderate
Area, submit plan provisions for RFP, RACM, RACT, an emissions
inventory, an emissions statement, motor vehicle I/M, a NNSR program
with the classification's general offset requirements, and control
measures needed to provide for attainment by the applicable attainment
deadline.\4\
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    \3\ On February 16, 2018 the DC Circuit issued a decision on the
2008 ozone NAAQS SRR. The adverse holdings of the case do not affect
our proposal action.
    \4\ We approved the motor vehicle I/M, NNSR, and offsets for the
DFW Moderate NAA under the 2008 ozone NAAQS at 82 FR 27122 (June 14,
2017). We approved the NOX rules on April 13, 2016 at 81
FR 21747 and NOX RACT for all affected sources but for
one cement manufacturing company at 82 FR 44320 (September 22,
2017); and the VOC rules and VOC RACT were approved December 21,
2017 at 82 FR 60546. We approved the RFP requirements at 81 FR 88124
(December 7, 2016). We approved the emissions inventory at 80 FR
9204 (February 20, 2015). We previously approved provisions for an
emissions statement program for the 1997 1-hour ozone NAAQS at 59 FR
44036 (August 26, 1994). In a separate action, we expect to propose
to convert the conditional approval of the cement company to a full
approval as RACT and propose that the emissions statement program
for the DFW Moderate NAA meets the 2008 ozone NAAQS requirements.
These two SIP elements are separate from a review of an attainment
demonstration SIP.
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    The attainment demonstration requirements for the 2008 ozone
standard can be found in 40 CFR 51.1108 (Modeling and attainment
demonstration requirements) and 40 CFR 51.112 (Demonstration of
adequacy); these requirements are described fully in the Technical
Support Documents (TSD), provided in the docket for this proposed
action.
    In general, an ozone attainment demonstration includes a
photochemical modeling analysis and other evidence (referred to as
``Weight of Evidence'') (WOE) showing how an area will achieve the
standard as expeditiously as practicable, but no later than the
attainment date specified for its classification.
    Below we discuss the statutory and regulatory requirements that
prescribe our review of the State's attainment demonstration, the
elements in the State's submittal, and our evaluation of those elements
comprising the attainment demonstration SIP. As stated

above, we previously approved several of the State's nonattainment area
plan requirements. We are evaluating the attainment demonstration and
its associated MVEBs, RACM, and contingency measures plan in the event
of failure to attain the NAAQS by the applicable attainment date in
this action.

II. The EPA's Evaluation

A. Review of Eight-Hour Attainment Demonstration Modeling and Weight of
Evidence

    EPA's regulations at 40 CFR 51.1108(c) specifically require that
areas classified as moderate and above submit a modeled attainment
demonstration based on a photochemical grid modeling evaluation or any
other analytical method determined by the Administrator to be at least
as effective as photochemical modeling. Section 51.1108(c) also
requires each attainment demonstration to be consistent with the
provisions of 40 CFR 51.112, including Appendix W to 40 CFR part 51
(i.e., ``EPA's Guideline on Air Quality Models,'' 70 FR 68218, November
9, 2005 and 82 FR 5182, January 17, 2017). See also EPA's ``Guidance on
the Use of Models and Other Analyses for Air Quality Goals in
Attainment Demonstrations for Ozone, PM2.5, and Regional
Haze,'' April 2007 and ``Draft Modeling Guidance for Demonstrating
Attainment of Air Quality Goals for Ozone, PM2.5, and
Regional Haze,'' December 2014 (hereafter referred to as ``EPA's 2007
A.D. guidance'' and ``EPA's 2014 Draft A.D. guidance''), which describe
criteria that an air quality model and its application should meet to
qualify for use in an 8-hour ozone attainment demonstration. For the
detailed review of modeling and the WOE analyses and EPA's analysis of
the DFW 8-hour Ozone attainment demonstration see the ``Modeling and
Other Analyses Attainment Demonstration'' (MOAAD) Technical Support
Document (TSD). The MOAAD TSD also includes a complete list of
applicable modeling guidance documents. These guidance documents
provide the overall framework for the components of an attainment
demonstration, how the modeling and other analyses should be conducted,
and overall guidance on the technical analyses for attainment
demonstrations.
    As with any predictive tool, there are inherent uncertainties
associated with photochemical modeling. EPA's guidance recognizes these
uncertainties and provides approaches for considering other analytical
evidence to help assess whether attainment of the NAAQS is
demonstrated. This process is called a WOE determination. EPA's
modeling guidance (updated in 1996, 1999, and 2002) discusses various
WOE approaches. EPA's modeling guidance has been further updated in
2005, 2007 and a Draft in 2014 for the 1997 and 2008 8-hour ozone
attainment demonstration procedures to include a WOE analysis as a part
of any attainment demonstration. This guidance recommends that all
attainment demonstrations include supplemental analyses beyond the
recommended modeling. These supplemental analyses would provide
additional information such as data analyses, and emissions and air
quality trends, which would help strengthen the overall conclusion
drawn from the photochemical modeling. EPA's Guidance for 1997 8-hour
ozone SIPs recommended that a WOE analysis be included as part of any
attainment demonstration SIP where the modeling results predict Future
Design Values (FDVs) ranging from 82 to less than 88 ppb (EPA's 2005
and 2007 A.D. Guidance documents).\5\ EPA's recent 2014 Draft A.D.
Guidance removed the specific range and indicated that WOE should be
analyzed when the results of the modeling attainment test are close to
the standard. EPA's interpretation of the Act to allow a WOE analysis
has been upheld. See 1000 Friends of Maryland v. Browner, 265 F. 3d 216
(4th Cir. 2001) and BCCA Appeal Group v. EPA, 355 F.3d 817 (5th Cir.
2003).
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    \5\ A.D. is Attainment Demonstration.
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    TCEQ submitted the DFW attainment demonstration SIP with
photochemical modeling and a WOE analyses on August 5, 2016. The
results of the photochemical modeling and WOE analyses are discussed
below.
1. What is a photochemical grid model?
    Photochemical grid modeling is the state-of-the-art method for
predicting the effectiveness of control strategies in reducing ozone
levels. The models use a three-dimensional grid to represent conditions
in the area of interest. TCEQ chose to use the Comprehensive Air Model
with Extensions (CAMx), Version 6.20 photochemical model for this
attainment demonstration SIP. The model is based on well-established
treatments of advection, diffusion, deposition, and chemistry. TCEQ has
used the CAMx model in other SIPs and EPA has approved many SIPs using
CAMx based modeling analyses. 40 CFR part 51 Appendix W indicates that
photochemical grid models should be used for ozone SIPs and lists a
number of factors to be considered in selecting a photochemical grid
model to utilize. EPA has reviewed the TCEQ's reasons for selecting
CAMx and EPA agrees with the choice by TCEQ to utilize CAMx for this
SIP.
    In this case, TCEQ has developed a modeling grid system that
consists of three nested grids. The outer grid stretches from west of
California to east of Maine and parts of the Atlantic Ocean to the
east, and from parts of southern Canada in the north to and much of
Mexico to the south extending to near the Yucatan Peninsula on the
southern edge. The model uses nested grid cells of 36 km on the outer
portions, 12 km for most of the Region 6 states (most of New Mexico and
all of Oklahoma, Arkansas, Louisiana, and Texas) and 4-kilometer grid
cells for much of Texas (not including West Texas and the Panhandle)
and portions of nearby States. The 4-kilometer grid cells include the
DFW Nonattainment Area. For more information on the modeling domain,
see the MOAAD TSD. The model simulates the movement of air and
emissions into and out of the three-dimensional grid cells (advection
and dispersion); mixes pollutants upward and downward among layers;
injects new emissions from sources such as point, area, mobile (both
on-road and nonroad), and biogenic into each cell; and uses chemical
reaction equations to calculate ozone concentrations based on the
concentration of ozone precursors and incoming solar radiation within
each cell. Air quality planners choose historical time period(s)
(episode(s)) of high ozone levels to apply the model. Running the model
requires large amounts of data inputs regarding the emissions and
meteorological conditions during an episode.
    Modeling to duplicate conditions during an historical time period
is referred to as the base case modeling and is used to verify that the
model system can predict historical ozone levels with an acceptable
degree of accuracy. It requires the development of a base case
inventory, which represents the emissions during the time period for
the meteorology that is being modeled. These emissions are used for
model performance evaluations. Texas modeled much of the 2006 ozone
season (May 31-July 2 and August 13-September 15), so the base case
emissions and meteorology are for 2006. If the model can adequately
replicate the measured ozone levels in the base case and responds
adequately to diagnostic tests, it can then be used to project the
response of future ozone levels to proposed emission control
strategies.

2. Model Selection
    TCEQ chose to use recent versions of Weather Research and
Forecasting Model (WRF) version 3.2 for the meteorological modeling,
Emission Processing System (EPS) version 3 for the emission processing,
and CAMx version 6.20 for the photochemical grid modeling. WRF is
considered a state of the science meteorological model and its use is
acceptable in accordance with 40 CFR part 51 Appendix W Section 5. The
combination of EPS for emissions processing and CAMx for photochemical
modeling constitutes one of the two predominant modeling platforms used
for SIP level modeling. These models and versions that TCEQ used are
acceptable and in accordance with 40 CFR part 51 Appendix W Section 5.
3. What episode did Texas choose to model?
    Texas chose to model much of the 2006 ozone season which included a
number of historical episodes with monitored exceedances. The 2006
ozone season was a period when multiple exceedance days occurred with a
good representation of the variety of meteorological conditions that
lead to ozone exceedances in the DFW NAA. Texas chose to model May 31-
July 2, 2006 and August 13-September 15, 2006. In addition, Texas
conducted the TexAQS II air quality field study in Houston, Dallas, and
throughout the eastern half of Texas during 2006 providing additional
data that was helpful in modeling and accessing model performance for
these periods for the DFW A.D.
    We evaluated Texas' 2006 episode selection for consistency with our
modeling guidance (2007, and Draft 2014 versions). Among the items that
we considered were the ozone levels during the selected period compared
to the design value \6\ (DV) at the time; how the meteorological
conditions during the proposed episode match with the conceptual model
of ozone exceedances that drive the area's DV; were enough days
modeled; and was the time period selected robust enough to represent
the area's problem for evaluating future control strategies. EPA's
guidance indicates that all of these items should be considered when
evaluating available episodes and selecting episodes to be modeled. EPA
believes that the two 2006 periods (May 31-July 2 and August 13-
September 15) are acceptable time periods for use in TCEQ's development
of the 8-hour ozone attainment plan. We note that this is an older
episode but it is one of the few years with a significant number of
exceedances compared to most other years in the 2006-2012 period that
were available when Texas started the modeling effort for this SIP in
the 2012/2013 timeframe. The only other potential period we had
previously identified with Texas was the 2012 ozone season, which TCEQ
did investigate but they were not able to get acceptable base case
model performance in time for use in this SIP revision in the
meteorological and ozone modeling for this 2012 episode in the DFW area
at the time this SIP was being developed. The 2006 period also had the
unique benefit of additional field data collected as part of TexAQS II.
EPA guidance suggests that having the extra field data is advantageous.
In light of all this information, EPA concurs with this episode being
adequate. See the MOAAD TSD for further discussion and analysis.
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    \6\ The design value is the 3-year average of the annual fourth
highest daily maximum 8-hour average ozone concentration (40 CFR 50,
Appendix I).
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4. How well did the model perform?
    Model performance is a term used to describe how well the model
predicts the meteorological and ozone levels in an historical episode.
EPA has developed various diagnostic, statistical and graphical
analyses that TCEQ has performed to evaluate the model's performance to
determine if the model is working adequately to test control
strategies. TCEQ performed many analyses of both interim model runs and
the final base case model run and deemed the model's performance
adequate for control strategy development. As described below, we agree
that the TCEQ's model performance is adequate.
    From 2012 to 2016, several iterations of the modeling were
performed by TCEQ incorporating various improvements to the
meteorological modeling, the 2006 base case emissions inventory, and
other model parameters. TCEQ shared model performance analyses with EPA
and EPA provided input. This data included analysis of meteorological
outputs compared to benchmark statistical parameters that TCEQ
previously developed as target values that are being used in many areas
of the country. TCEQ also shared graphical analyses of the meteorology
with EPA. In addition, TCEQ shared extensive analyses of the
photochemical modeling for several base case modeling runs with EPA.
    EPA has reviewed the above information and is satisfied that the
meteorological modeling was meeting most of the statistical benchmarks,
and was transporting air masses in the appropriate locations for most
of the days.\7\ EPA also conducted a review of the model's performance
in predicting ozone and ozone precursors and found that performance was
within the recommended 1-hour ozone statistics for most days. We
evaluate 1-hour time series and metrics as this information has less
averaging/smoothing than the 8-hour analyses and results in a higher
resolution for evaluating if the modeling is getting the rise and fall
of ozone in a similar manner as the monitoring data. We also evaluated
the 8-hour statistics, results of diagnostic and sensitivity tests, and
multiple graphical analyses and determined that overall the ozone
performance was acceptable for Texas to move forward with future year
modeling and development of an attainment demonstration.
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    \7\ There are a number of time series and statistical analyses
that EPA evaluates in determining if meteorological modeling and
ozone modeling is acceptable and EPA compares these analyses in
context with other SIPs and modeling conducted for EPA rulemaking to
see if the modeling meets most of the benchmarks and is acceptable.
EPA's modeling guidance for both meteorological modeling and ozone
modeling indicates general goals for model performance statistics
based on what EPA has found to be acceptable model performance goals
from evaluations of a number of modeling analyses conducted for SIPs
and Regulatory development. EPA's guidance also indicates that none
of the individual statistics goals is a ``pass/fail'' decision but
that the overall suite of statistics, time series, model
diagnostics, and sensitivities should be evaluated together in a
holistic approach to determine if the modeling is acceptable.
Modeling is rarely perfect, so EPA's basis of acceptability is if
the model is working reasonably well most of the time and is doing
as well as modeling for other SIPs and EPA rulemaking efforts. For
more details on model performance analyses and acceptability see the
MOAAD TSD. (EPA 2007 A.D. Guidance, EPA 2014 Draft A.D. Guidance,
Emery, C., and E. Tai, (2001), ``Enhanced Meteorological Modeling
and Performance Evaluation for Two Texas Ozone Episodes ``, prepared
for the Texas Near Non-Attainment Areas through the Alamo Area
Council of Governments'', by ENVIRON International Corp, Novato, CA)
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    EPA does not expect any modeling to necessarily be able to meet all
the EPA model performance goals, but relies on a holistic approach to
determine if the modeling is meeting enough of the goals, the time
series are close enough and diagnostic/sensitivity modeling indicates
the modeling is performing well enough to be used for assessing changes
in emissions for the model attainment test.\8\ EPA agrees that the
overall base case model performance is acceptable, but notes that even
with the refinements, the modeling still tends to have some bias
performance concerns on the higher ozone days with some of the days
being over predicted and some

under predicted. The modeling also tended to have a slight
overprediction bias for the Kaufman monitor which is usually upwind of
the DFW area and more representative of background ozone entering the
DFW area. See the MOAAD TSD for further analysis.
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    \8\ Id.
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5. Once the base case is determined to be acceptable, how is the
modeling used for the attainment demonstration?
    Before using the modeling for attainment test and potential control
strategy evaluation, TCEQ reviewed the base case emission inventory,
and made minor adjustments to the inventory to account for things that
would not be expected to occur again or that were not normal (examples:
Inclusion of EGUs that were not operating due to temporary shutdown
during the base case period but were expected to be operating in 2017,
adjusting the hour specific EGUs CEM based NOX emissions to
a typical Ozone season day emission rate). This adjusted emission
inventory is called the 2006 baseline emission inventory. The
photochemical model was then executed again to obtain a 2006 baseline
model projection.
    Since DFW is classified as a moderate NAA, the attainment deadline
is as expeditiously as practicable but no later than July 20, 2018. To
meet this date, it is necessary for emission reductions to be in place
by no later than what is termed the attainment year, which in this case
is 2017. Future case modeling using the base case meteorology and
estimated 2017 emissions is conducted to estimate future ozone levels
factoring in the impact of economic growth in the region and State and
Federal emission controls.
    EPA guidance recommends that the attainment test use the modeling
analysis in a relative sense instead of an absolute sense. To predict
future ozone levels, we estimate a value that we refer to as the Future
Design Value (FDV). First, we need to calculate a Base Design Value
(BDV) from the available monitoring data. The BDV is calculated for
each monitor that was operating in the base period by averaging the
three DVs that include the base year (2006). The DVs for 2004-2006,
2005-2007, and 2006-2008 are averaged to result in a center-weighted
BDV for each monitor.
    To estimate the FDV, a value is also calculated for each monitor
that is called the Relative Response Factor (RRF) using a ratio of
baseline and future modeling results around each monitor. This
calculation yields the RRF for that monitor. The RRF is then multiplied
by the Base Design Value (BDV) for each monitor to yield the FDV for
that monitor. The modeled values for each monitor may be calculated to
hundredths of a ppb, then truncated to an integer (in ppb) as the final
step in the calculation as recommended by EPA's guidance. The truncated
values are included in the tables in this action. TCEQ employed EPA's
recommended approach for calculating FDV's. For information on how the
FDV is calculated refer to the MOAAD TSD.
    The 2014 Draft A.D. Guidance indicates that instead of using all
days above the standard (75 ppb) in the baseline, that the subset of 10
highest baseline days at each monitor should be used for calculating an
RRF.\9\ The 10 highest days are the 10 highest 8-hour maximum daily
values at each specific monitor. TCEQ provided the 2017 FDV values for
each of the monitors using both procedures (2007 A.D Guidance and 2014
Draft A.D. Guidance).
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    \9\ The 10 highest baseline days at a monitor are summed and
become the denominator and the future year values for the same 10
days are summed and become the numerator in the RRF calculation.
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    EPA has reviewed the components of TCEQ's photochemical modeling
demonstration and finds the analysis meets 40 CFR part 51, including 40
CFR part 51 Appendix W--Guideline on Air Quality Models. For a more
complete description of the details of the base case modeling inputs,
set-up, settings, the meteorology and photochemical model performance
analysis (and EPA's evaluation of these procedures and conclusions),
see the MOAAD TSD in the Docket for this action (EPA-RO6-OAR-2016-
0476).
6. What did the results of TCEQ's 2017 future year attainment
demonstration modeling show?
    The results of modeling the 2017 future baseline modeling run are
shown in Table 1. In Table 1, the model FDV calculations using both
EPA's 2007 A.D. Guidance method calculation and the more recent 2014
Draft A.D. Guidance calculation method are shown. We have calculated
the FDVs in the following tables using the final truncated numbers in
accordance with EPA guidance. EPA's more recent 2014 Draft A.D.
Guidance to use just the top 10 (highest) 8-hour days from the 2006
baseline modeling instead of all days is a result of previous ozone
analyses that EPA reviewed and determined that the older 2007 A.D.
Guidance method can include too many days when modeling an area that
can have many exceedances and can result in underestimating actual
FDVs. Using the top 10 days shifts the focus of the attainment test to
the highest and typically hardest days at each monitor. EPA's 2014
Draft A.D. Guidance has not been finalized as the guidance also covers
PM2.5 and Regional Haze and EPA has delayed finalization
while changes in the Regional Haze Rules and guidance have been under
review. We have evaluated both approaches in the DFW modeling and are
focusing on the 2014 Draft A.D. modeling results because we find it
represents a more appropriate analysis of the attainment test. For
example, the 2007 A.D. Guidance method results in 34 modeled days being
used in the attainment test for the Denton monitor which includes a
number of days where overall ozone was predicted to exceed in the 2006
baseline but was not predicted to exceed in the 2017 modeling analysis.
As a result, this older guidance appears to include a number of days
that are not predicted to be high ozone or exceedance days in 2017 but
are still included in calculating an RRF and a FDV for the monitor.
EPA's full analysis for this DFW modeling, of the two FDV calculations,
and our results/conclusions for all the monitors is included in the
MOAAD TSD. Table 1 includes the modeling projections prior to
evaluating any other modeling sensitivity runs.

                                   Table 1--SIP Modeling Projections for 2017
----------------------------------------------------------------------------------------------------------------
                                                                                Top 10 2006 baseline days >75
                                                                                (ppb)
 2006 DFW area monitor and CAMS      2006 DVB        2017 DVF     2017 Truncated -------------------------------
              code                     (ppb)           (ppb)        DVF  (ppb)                         2017
                                                                                2017 DVF      Truncated DVF
                                                                                (ppb)           (ppb)
----------------------------------------------------------------------------------------------------------------
Denton Airport South--C56.......           93.33           77.86              77           76.26              76

Eagle Mountain Lake--C75........           93.33           77.52              77           76.55              76
Grapevine Fairway--C70..........           90.67            77.2              77           75.65              75
Keller--C17.....................              91           76.77              76           75.35              75
Fort Worth Northwest--C13.......           89.33           75.94              75           74.78              74
Frisco--C31.....................           87.67            74.4              74           73.85              73
Dallas North #2--C63............              85           73.35              73           72.23              72
Dallas Executive Airport--C402..              85           72.21              72           72.05              72
Parker County--C76..............           87.67           72.17              72            72.4              72
Cleburne Airport--C77...........              85            71.1              71           69.86              69
Dallas Hinton Street--C401......           81.67           70.96              71           69.31              69
Arlington Municipal Airport--C61           83.33           70.57              70           69.86              69
Granbury--C73...................              83           68.73              68           68.41              68
Midlothian Tower--C94...........            80.5           67.77              67           67.44              67
Pilot Point--C1032..............              81            67.4              67            66.6              66
Rockwall Heath--C69.............           77.67           65.65              65           65.81              65
Midlothian OFW--C52.............              75           63.17              63           62.57              62
Kaufman--C71....................           74.67           62.04              62           62.11              62
Greenville--C1006...............              75           61.78              61           62.09              62
----------------------------------------------------------------------------------------------------------------

    The second column is the Base DV for the 2006 period. Using the
2007 A.D. guidance 15 of the 19 DFW area monitors are in attainment,
one has a FDV of 76 ppb and 3 monitors have a FDV of 77 ppb. Using the
2014 Draft A.D. Guidance all but two of the monitors are attainment.
Two are projected to be near attainment with a FDV of 76 ppb. The two
monitors over 76 ppb have modeled values of 76.55 and 76.26 at Eagle
Mountain Lake and Denton Monitors and are 0.56 and 0.27 ppb from
attainment values.\10\
---------------------------------------------------------------------------

    \10\ A model value of 75.99 would be truncated to 75 ppb.
---------------------------------------------------------------------------

    The standard attainment test is applied only at monitor locations.
The 2007 A.D. Guidance and the 2014 Draft A.D. Guidance both recommend
that areas within or near nonattainment counties but not adjacent to
monitoring locations be evaluated in an unmonitored areas (UMA)
analysis to demonstrate that these UMAs are expected to reach
attainment by the required future year. The UMA analysis is intended to
identify any areas not near a monitoring location that are at risk of
not meeting the NAAQS by the attainment date. EPA provided the Modeled
Attainment Test Software (MATS) to conduct UMA analyses, but has not
specifically recommended in EPA's guidance documents that the only way
of performing the UMA analysis is by using the MATS software. EPA has
allowed states to develop alternative techniques that may be
appropriate for their areas or situations.
    TCEQ used their own UMA analysis (called the TCEQ Attainment Test
for Unmonitored areas or TATU). EPA previously reviewed TATU during our
review of the modeling protocol for the HGB area (2010 Attainment
Demonstration SIP) and we are proposing approval of the use of TATU's
tool and its Unmonitored Area analysis as acceptable for meeting the
recommended evaluation of ozone levels in the Unmonitored Area analysis
for this SIP approval action (See MOAAD TSD for review and evaluation
details). The TATU is integrated into the TCEQ's model post-processing
stream and MATS requires that modeled concentrations be exported to a
personal computer-based platform, thus it would be more time consuming
for TCEQ to use MATS for the UMA. Based on past analysis, results
between TATU and MATS are similar and EPA's guidance (2007 and Draft
2014) provides states the flexibility to use other tools for the UMA.
    The TATU analysis included in the SIP indicates the maximum in the
unmonitored areas is not significantly different than the 2017 FDVs
calculated using all days above 75 ppb in the baseline (2007 A.D.
Guidance). TCEQ has not adjusted the TATU tool to use the FDVs from the
10-Day FDV calculation procedure in the 2014 Draft A.D. Guidance.
TCEQ's TATU analysis indicates the highest values are in the same area
as the five monitors that typically record the highest ozone levels in
the DFW area, located north and west of Fort Worth: Denton Airport
South, Eagle Mountain Lake, Fort Worth Northwest, Grapevine, and
Keller. We agree with TCEQ's analysis that there are not areas outside
of the monitored areas that are of concern and the highest area in the
unmonitored analysis is in the heavily monitored area in the northwest
quadrant of the DFW area, consistent with the 5 monitors listed above.
Therefore, the 2017 FDVs are properly capturing the geographic
locations of the monitored peaks and no significant hotspots were
identified that need to be further addressed.
    For a more complete description of the modeling attainment test
procedures and conclusions and EPA's evaluation of these procedures and
conclusions, see the MOAAD TSD in the Docket for this action.
7. What are EPA's conclusions of the modeling demonstration?
    EPA has reviewed the modeling and modeling results and finds they
meet 40 CFR part 51 requirements. The modeling using the 2014 Draft
A.D. Guidance indicates that 17 out of 19 of the monitors are projected
to be in attainment in 2017 while two monitors have 2017 FDVs just
above the 2008 8-hour Ozone NAAQS (75 ppb). EPA concludes that the
modeling results are within the range \11\ where EPA

recommends Weight of Evidence (WOE) be considered to determine if the
attainment demonstration is approvable.
---------------------------------------------------------------------------

    \11\ 2007 A.D. Guidance indicated within 2-3 ppb for the 1997 8-
hour 85 ppb standard and the 2014 Draft A. D. Guidance indicated the
model results should be close to the standard without giving an
exact range. The two values over with the 2014 Draft A.D. Guidance
are just 1 ppb over the standard and EPA considers this be within
the range of `close' as indicated by the guidance (2014 Draft A.D.
Guidance page 190 ``In conclusion, the basic criteria required for
an attainment demonstration based on weight of evidence are as
follows: (1) A fully-evaluated, high-quality modeling analysis that
projects future values that are close to the NAAQS.''
---------------------------------------------------------------------------

8. Weight of Evidence (WOE)
a. Background
    Both EPA's 2007 A.D. and 2014 Draft A.D. guidance documents
recommend that in addition to a modeling demonstration, the states
include WOE when the modeling results in FDVs are close to the
standard. EPA's 2007 A.D. and 2014 Draft A.D. guidance documents both
discuss additional relevant information that may be considered as WOE.
The 2007 A.D. Guidance that was developed for the 1997 8-hour ozone
standard of 85 ppb standard had a range of 82-87 ppb where a WOE
analysis was recommended to support the attainment test. Applying that
guidance's general principle to the 2008 8-hour ozone standard of 75
ppb, the DFW FDVs fall within the 2-3 ppb range of that guidance where
WOE should also be considered. The 2014 Draft A.D. Guidance does not
set a range but indicates that the FDVs should be close to the standard
to use WOE, and EPA considers these 2017 FDVs to be very close to the
standard (less than 1 ppb in both guidance cases).
    A WOE analysis provides additional scientific analyses as to
whether the proposed control strategy, although not modeling
attainment, demonstrates attainment by the attainment date. The intent
of EPA's guidance is to utilize the WOE analysis to consider potential
uncertainty in the modeling system and future year projections. Thus,
in the DFW case, even though the modeling predicts two out of 19
monitors have FDVs that are 1 ppb above the NAAQS, additional
information (WOE) can provide a basis to conclude attainment is
demonstrated. EPA's guidance indicates that several items should be
included in a WOE analyses, including the following: Additional
modeling, additional reductions not modeled, recent emissions and
monitoring trends, known uncertainties in the modeling and/or emission
projections, and other pertinent scientific evaluations. Pursuant to
EPA's guidance, TCEQ supplemented the control strategy modeling with
WOE analyses.
    We briefly discuss the more significant components of the WOE that
impacted EPA's evaluation of the attainment demonstration in this
action. Many other elements are discussed in the MOAAD TSD. For EPA's
complete evaluation of the WOE considered for this action, see the
MOAAD TSD.

b. What additional modeling-based evidence did Texas provide?

    Texas submitted a significant body of information as WOE in the
August 5, 2016 submittal. The Texas attainment demonstration modeling
discussed above included a model sensitivity run with different Texas
EGU emission levels to indicate how slight changes in Texas EGU
NOX emission budgets would impact projected 2017 FDVs in the
DFW area. Texas increased the SIP modeling TX EGU emissions that are
based on Cross State Air Pollution Rule (CSAPR) 12 13 by
2.75% using the older Texas EGU ozone season NOX budget and
source allocations from the Clean Air Interstate Rule (CAIR).\14\ This
slight increase in EGU NOX emissions resulted in a small
increase of the FDV of 0.08 ppb at the Denton monitor. TCEQ conducted
this sensitivity analysis in 2015, prior to EPA finalizing the CSAPR
Update Budget for the 2008 ozone standard.\15\ EPA has evaluated the
new CSAPR Update Texas EGU ozone season NOX budget which
results in a 20% decrease in emissions compared to the previous CSAPR
budget that was included in the attainment modeling. The CSAPR Update
required compliance with the new budget starting in May 1, 2017 which
is the start of the core period of DFW ozone season. While these
reductions were not modeled by TCEQ and occur after the start of the
DFW ozone season, based on TCEQ's sensitivity modeling we would expect
these EGU NOX reductions to result in lower ozone levels at
DFW monitors during the core DFW ozone season of May through September
and provide positive WOE.
---------------------------------------------------------------------------

    \12\ Cross State Air Pollution Rule (CSAPR) Federal Register, 76
FR 48208 (July 6, 2011) and Federal Register, Federal Register, 76
FR 80760 (December 15, 2011).
    \13\ See Sections Section 3.5.4; 3.7.4 Future Case Modeling
Sensitivities; <IP_ADDRESS> 2017 Clean Air Interstate Rule (CAIR) Phase
II Sensitivity; <IP_ADDRESS> of the State's August 5, 2016 SIP submittal.
    \14\ Clean Air Interstate Rule (CAIR) Federal Register, 70 FR
25162 (May 21, 2005).
    \15\ Cross State Air Pollution Rule Update for the 2008 Ozone
NAAQS Federal Register, 81 FR 74504 (October 26, 2016).
---------------------------------------------------------------------------

    TCEQ also used a modeling concept that tracks the ozone generated
in the modeling from ozone precursors by location and category of type
of emission source that is referred to as using source
apportionment.\16\ For 2017 and 2018, TCEQ performed source
apportionment modeling using the Anthropogenic Precursor Culpability
Assessment (APCA) tool.\17\ On the 10 highest days at each monitor, the
APCA indicated that DFW sources contribute more on the 10 highest days.
For these 10 highest days at the downwind monitors of Denton and Eagle
Mountain Lake, the amount of ozone at the monitor due to emissions from
local DFW sources was often in the 25-35 ppb range and combination of
all Texas sources (DFW and rest of Texas) was often 33-43 ppb. This
source apportionment indicates that on the worst days in the DFW area,
local emission reductions and reductions within Texas are more
beneficial than on other baseline exceedance days. This adds a positive
WOE that DFW area reductions in mobile on-road and non-road categories
as well as other categories aid in demonstrating attainment. When we
say positive WOE, EPA is indicating that the WOE element factors more
into supporting the demonstration of attainment. For EPA's complete
evaluation of the modeled WOE elements considered for this action, see
the MOAAD TSD.
---------------------------------------------------------------------------

    \16\ Source apportionment allows the tracking of ozone
generation from regions (such as upwind states or the DFW NA, etc.)
and also by source category (such as on-road, nonroad, EGU, point
sources, etc.).
    \17\ See 3.7.3 of the State's August 5, 2016 SIP submittal.
---------------------------------------------------------------------------

c. Other Non-Modeling WOE
    TCEQ showed that 8-hour and 1-Hour ozone DVs have decreased over
the past 18 years, based on monitoring data in the DFW Area (1997
through 2014). TCEQ indicated that the 2015 8-hour ozone DV for the DFW
nonattainment area is 83 ppb at Denton Airport South, which is in
attainment of the former 8-hour standard (85 ppb) and demonstrates
progress toward the current 75 ppb standard.
    TCEQ's trend line for the 1-Hour ozone DV shows a decrease of about
2.1 ppb per year, and the trend line for the 8-hour ozone DV shows a
decrease of about 1.1 ppb per year. The 1-Hour ozone DVs decreased
about 27% from 1997 through 2014 and the 8-hour ozone DVs decreased
about 21% over that same time. This is positive WOE that supports the
demonstration of attainment.
    EPA has also supplemented TCEQ's monitoring data analysis with more
recent 2014-2016 and preliminary 2017 monitoring data \18\ (See Tables
3 and 4).

The Denton monitor is located to the north-northwest of the DFW
nonattainment area, which is downwind of the urban core and has been
the highest DV monitor in DFW and has been setting the DFW NAA DV for
the 2014 to 2016 years (and preliminarily in 2017) as the monitor with
the highest measured DV. The 2016 DV (2014-2016 data) data indicates
that only two monitors had a DV above the standard (Denton--80 ppb and
Pilot Point 76 ppb). Current preliminary 2015-2017 DV data indicates
that only one of the nineteen monitors in the DFW area may be above the
standard with a preliminary 2017 DV of 79 at Denton.\19\
---------------------------------------------------------------------------

    \18\ The 2017 monitoring data is preliminary and still has to
undergo Quality Assurance/Quality Control analysis and be certified
by the State of Texas, submitted to EPA, and reviewed and concurred
on by EPA.
    \19\ Any determination of whether the DFW ozone nonattainment
area has attained by the applicable attainment date is a separate
analysis that will be part of a separate EPA rulemaking. This
rulemaking is focused on whether the State's submitted attainment
demonstration is approvable under CAA standards. EPA is not in a
position at this time to determine whether the DFW area has attained
by the applicable attainment date, given that that the attainment
date has not yet passed and the 2017 monitoring data is still
preliminary.
---------------------------------------------------------------------------

    The monitored DV is calculated by averaging the 4th High values
from three consecutive years and truncating to integer (whole number)
level in ppb. For example, the 2016 DV is the average of 4th Highs from
2014-2016. The DV calculations can be driven by one high year (2015 in
this case) so, for WOE purposes, we can also look at the 4th High 8-
hour values for each recent year.
    Overall as seen in Table 3 and 4 below, 2015 stands out with high
ozone monitored data compared to other recent years (2014, 2016 and
preliminary 2017). These 4th High 8-hour values support that the area
with recent emission levels has been close to attaining the standard
for several years. The high 2015 4th High 8-hour data is driving all
the DVs for 2015, 2016, and preliminary 2017. Despite the high 2015 4th
High 8-hour data that contributed to higher 2015, 2016, and preliminary
2017 DV values, examination of the 4th High 8-hour values for 2014,
2016 and preliminary 2017, support the finding that the general long-
term trend identified by TCEQ of a steady reduction in DV should
continue.
    To assess what might have occurred if 2015 had not been such a high
year we have calculated the average of the last two years (2016 and
preliminary 2017) 4th Highs, and all monitors have values that are 1
ppb or more below the standard (values are 74.5 ppb or less).\20\ Both
the individual 4th High monitoring data from 2014, 2016, and 2017 and
the average of the 2016 and preliminary 2017 data are some of the
strongest, positive WOE. The ozone data indicates that emission levels
in DFW NAA and the meteorology that occurred in 2014, 2016, and 2017
have led to ozone levels that are consistent with attainment of the
NAAQS. Overall, with the exception of the high 2015 data, the recent
monitoring data provides a strong positive WOE that supports the
demonstration of attainment.
---------------------------------------------------------------------------

    \20\ When calculating a DV, the three consecutive years 4th
highs are averaged and then truncated. For this discussion consider
a hypothetical example of a monitor with 4th High values of 75 ppb,
76 ppb, and 76 ppb that would average to 75.67 and then be truncated
to 75 ppb and be in attainment of the 75 ppb NAAQS. Therefore, the
non-truncated value of the 2-year avg.74.5 ppb at the Denton monitor
is over 1 ppb lower than 75.67 ppb.

                                         Table 3--DFW Area Monitors DVs
                                                 [2014-2017] \1\
----------------------------------------------------------------------------------------------------------------
                                                                                2016-2017 \1\
                                    2014  (ppb)     2015 (ppb)      2016 (ppb)    2017 \1\ (ppb)   (2 year avg.)
----------------------------------------------------------------------------------------------------------------
Denton Co. Airport..............              81              83              80              79            74.5
Pilot Point.....................              79              79              76              74            71.5
Nuestra (North Dallas)..........              77              75              72              74              72
Hinton..........................              78              75              71              74              72
Executive.......................              74              68              64              64            62.5
Keller..........................              77              76              73              73            72.5
Meacham.........................              80              80              74              72            69.5
Arlington.......................              75              67              65              67              66
Eagle Mt. Lake..................              79              76              72              71            68.5
Grapevine.......................              80              78              75              75              74
Frisco..........................              78              76              74              74            72.5
Italy...........................              67              66              62              64              63
Midlothian Downwind.............              71              68              63              65            63.5
Granbury........................              76              73              69              67            64.5
Cleburne........................              76              73              72              73            73.5
Kaufman.........................              70              67              61              61            59.5
Parker Co.......................              74              75              73              70            66.5
Rockwall........................              73              70              66              66              64
Greenville......................              69              64              60              62              62
----------------------------------------------------------------------------------------------------------------
\1\ 2017 DV and 4th High 8-hour values are preliminary data.

                                Table 4--DFW Area Monitors 4th High 8-Hour Values
                                                 [2014-2017] \1\
----------------------------------------------------------------------------------------------------------------
                                                    2014 (ppb)      2015 (ppb)      2016 (ppb)    2017 \1\ (ppb)
----------------------------------------------------------------------------------------------------------------
Denton Co. Airport..............................              77              88              76              73
Pilot Point.....................................              75              79              75              68
Nuestra (North Dallas)..........................              70              79              67              77
Hinton..........................................              66              80              69              75
Executive.......................................              63              68              62              63
Keller..........................................              74              76              70              75
Meacham.........................................              79              79              66              73
Arlington.......................................              65              69              61              71

Eagle Mt. Lake..................................              73              78              67              70
Grapevine.......................................              73              79              75              73
Frisco..........................................              74              77              73              72
Italy...........................................              60              66              60              66
Midlothian Downwind.............................              62              68              60              67
Granbury........................................              73              73              63              66
Cleburne........................................              71              73              72              75
Kaufman.........................................              62              64              57              62
Parker Co.......................................              72              79              68              65
Rockwall........................................              66              71              61              67
Greenville......................................              62              62              58              66
----------------------------------------------------------------------------------------------------------------
\1\ 2017 4th High 8-hour values are preliminary data.

    TCEQ also submitted WOE components that are further discussed in
the MOAAD TSD including the following: Conceptual model and selection
of the 2006 period to fit the range of days and synoptic cycles that
yield high ozone in DFW, additional ozone design value trends, ozone
variability analysis and trends, NOX and VOC monitoring
trends, emission trends, NOX and VOC chemistry limitation
analysis, and local contribution analyses. Details of these WOE
components that also provide positive WOE are included in Chapter 5 of
the August 5, 2016 SIP submittal and discussed in the MOAAD TSD.
d. Other WOE Items From Texas Not Currently Quantified With Modeling:
Additional Programs/Reductions, etc.
    CEMENT KILNS--TCEQ also noted that the modeling for the Cement
Kilns in Ellis County was based on a NOX cap of 17.64 tons
per day when actual NOX emissions have been less than 10
tons per day. The modeling of the kiln emissions in the 2017 future
year modeling is high compared to actuals and even new permitted limits
and provides positive WOE. EPA's guidance in this case recommends the
cap limits be modeled. The fact that the three kilns have not operated
at their cap, two of the kilns have shut down and the shut downs are
permeant and enforceable, and the third kiln through reconstruction has
lower emissions, and the NOX reductions at Ash Grove
(NOX permitted reduction of 2.45 tons per day) provide
positive WOE.
    DFW AREA EMISSION REDUCTION CREDITS (ERC) AND DISCRETE EMISSION
REDUCTION CREDITS (DERC)--TCEQ indicated that they modeled the DFW area
ERCs and DERCs in the 2017 future year modeling and this is
conservative as it is unlikely that all these credits would be used in
one year. EPA agrees it might be conservative, but including the ERCs
and DERCs in the future year 2017 modeling is consistent with EPA's
guidance.\21\ EPA guidance calls for emission credits that are being
carried in the emissions bank to be included in modeled projections
because these emissions will come back in the air when and if the
credits are used and without any clear limit on annual usage it cannot
be clearly demonstrated that all the ERC/DERCs will not be used in the
2017 future year. It does provide positive WOE.
---------------------------------------------------------------------------

    \21\ See sections 12 and 16 of ``Improving Air Quality with
Economic Incentive Programs'' (EPA-452/R-01-001, January 2001).
---------------------------------------------------------------------------

    TEXAS EMISSION REDUCTION PLAN (TERP)--The TERP program provides
financial incentives to eligible individuals, businesses, or local
governments to reduce emissions from polluting vehicles and equipment.
In 2015, the Texas Legislature increased funding for TERP to $118.1
million per year for FY 2016 and 2017, which was an increase of $40.5
million per year which resulted in more grant projects in eligible TERP
areas, including the DFW area. Texas also noted that since the
inception of TERP in 2001 through August 2015, over $968 million
dollars have been spent within the state through TERP and the Diesel
Emission Reduction Incentive Program (DERI) that has resulted in
168,289 tons of NOX reductions in Texas by 2015. TCEQ also
noted that over $327 million in DERI grants have been awarded to
projects in the DFW area through 2015 resulting with a projected
NOX reduction of 58,062 tons that is also estimated as 18.7
tons per day of NOX. These DERI and TERP benefits were not
modeled but the reductions and future reductions do provide positive
WOE.
    LOW-INCOME VEHICLE REPAIR ASSISTANCE, RETROFIT, AND ACCELERATED
VEHICLE RETIREMENT PROGRAM (LIRAP)--TCEQ established a financial
assistance program for qualified owners of vehicles that fail the
emissions test. The purpose of this voluntary program is to repair or
remove older, higher emitting vehicles from use in certain counties
with high ozone. The counties currently participating in the LIRAP
include, but are not limited to Collin, Dallas, Denton, Ellis, Johnson,
Kaufman, Parker, Rockwall, and Tarrant. In DFW NAA between December 12,
2007 and February 29, 2016, the program repaired 39,379 vehicles at a
cost of $20.894 million and retired and replaced 55,807 vehicles at a
cost of $167.629 million. Participating DFW area counties were
allocated approximately $21.6 million per year for the LIRAP for FYs
2016 and 2017. This is an increase of approximately $18.8 million per
year over the previous biennium. These LIRAP benefits were not modeled
but the reductions and future reductions do provide positive WOE.
    LOCAL INITIATIVE PROJECTS (LIP)--Funds are provided to counties
participating in the LIP for implementation of air quality improvement
strategies through local projects and initiatives (Examples: Studies on
emissions inspection fraud and targeting high emission vehicles). The
2016 and 2017 state budgets included increases of approximately $2.1
million per year over previous biennium. These LIP benefits were not
modeled but the reductions and future reductions do provide positive
WOE.
    LOCAL INITIATIVES--The North Central Texas Council of Governments
(NCTCOG) submitted an assortment of locally implemented strategies in
the DFW nonattainment area including pilot programs, new programs, or
programs with pending methodologies. These Local Initiatives benefits
were not

modeled but the reductions and future reductions do provide positive
WOE.
    ENERGY EFFICIENCY/RENEWABLE ENERGY (EE/RE) MEASURES--Additional
quantified and unquantified WOE emissions reductions (without
NOX reductions calculated) include a number of energy
efficiency measures (Residential and Commercial Building Codes,
municipality purchase of renewable energies, political subdivision
projects, electric utility sponsored programs, Federal facilities EE/RE
Projects, etc.). These efforts are not easily quantifiable for an
equivalent amount of NOX reductions that may occur, but they
do provide positive WOE that growth in electrical demand is reduced and
this results in reduced NOX emissions from EGUs.
    VOLUNTARY MEASURES--While the oil and natural gas industry is
required to install controls either due to State or Federal
requirements, the oil and natural gas industry has in some instances
voluntarily implemented additional controls and practices to reduce VOC
emissions from oil and natural gas operations in the DFW nonattainment
area as well as other areas of the state. Since these are voluntary
measures and reporting/verification is not a requirement these efforts
are not easily quantifiable from an equivalent amount of NOX
and VOC reductions that may occur, but they do provide positive WOE
that emissions from oil and gas development which is beneficial to
lowering ozone formation from this sector.
9. Is the 8-hour attainment demonstration approvable?
    Consistent with EPA's regulations at 40 CFR 51.1108(c), Texas
submitted a modeled attainment demonstration based on a photochemical
grid modeling evaluation. EPA has reviewed the components of TCEQ's
photochemical modeling demonstration and finds the analysis is
consistent with EPA's guidance and meets 40 CFR part 51, including 40
CFR part 51 Appendix W--Guideline on Air Quality Models. The
photochemical modeling was conducted to project 2017 ozone levels in
order to demonstrate attainment of the standard by the attainment date.
Although the modeled attainment test is not fully met and two of the 19
DFW monitors were projected to be slightly above the standard (less
than 1 ppb), consistent with our A.D. guidance, TCEQ submitted a WOE
analysis. This WOE analysis provides additional scientific analyses
based on identification of emission reductions not captured in the
modeling, monitoring trends and recent monitoring data (EPA included
more recent monitoring data since the SIP submission) and other
modeling analyses. The combination of the modeling and the WOE
demonstrate attainment by the attainment date. We are therefore
proposing to approve the attainment demonstration submitted August 5,
2016.

B. Review of Other Plan Requirements

1. Emissions Inventory (EI)
    An emissions inventory is a comprehensive, accurate, and current
inventory of actual emissions from all relevant sources of pollutants
in the NAA. It is required by sections 172(c)(3) and 182(a)(1) of the
CAA that nonattainment plan provisions include an inventory of
NOX and VOC emissions from all sources in the nonattainment
area. EPA previously approved SIP revisions to the emissions inventory
for the DFW moderate nonattainment area for the 2008 ozone NAAQS. See
81 FR 88124 (December 7, 2016).
2. Nonattainment New Source Review (NNSR)
    The EPA approved the NNSR permitting program for the DFW NAA under
the 2008 ozone NAAQS at 82 FR 27122 (June 14, 2017). All NNSR programs
have to require (1) the installation of the lowest achievable emission
rate, (2) emission offsets, and (3) opportunity for public involvement.
3. Motor Vehicle Inspection and Maintenance (I/M)
    The EPA approved a State SIP revision for the 2008 8-hour ozone
NAAQS requirements for vehicle I/M. See 82 FR 27122 (June 14, 2017).
4. Reasonable Further Progress (RFP)
    On July 10, 2015, the TCEQ submitted a RFP SIP revision
(supplemented on April 22, 2016) to the EPA. For the 2008 ozone NAAQS,
the EPA fully approved the DFW moderate nonattainment area RFP SIP
revision, the associated contingency measures, and the 2017 RFP
Attainment Motor Vehicle Emission Budgets (MVEBs) on December 7, 2016
(81 FR 88124).
5. Reasonably Available Control Technology (RACT)
    Section 182(b)(2) of the Act requires states to submit a SIP
revision and implement RACT for major stationary sources in moderate
and above ozone nonattainment areas. Based on the moderate
classification of the DFW NAA for the 2008 ozone standard, a major
stationary source is one that emits, or has the potential to emit, 100
tpy or more of NOX or VOC. The EPA approved revisions to the
State's SIP that revised rules for control of VOC to assist the DFW NAA
in attaining the 2008 8-hour ozone NAAQS and that demonstrates that the
VOC RACT requirements are met for the DFW NAA. The approval includes
Wise County, a county previously added in the 2008 ozone designations,
as part of the DFW moderate NAA. We approved the submitted
NOX rules (that included Wise County) to assist the DFW NAA
in attaining the 2008 8-hour ozone NAAQS and then we approved the
NOX RACT demonstration as part of the DFW moderate NAA SIPs
but for one affected source.\22\ Our actions on the RACT for
NOX and VOC for the DFW NAA are found at 82 FR 44320 and 82
FR 60546.
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    \22\ As a separate requirement of the Act, the State must
demonstrate that the revised VOC and NOX control
strategies meet RACT. Again, we previously approved VOC RACT for the
DFW NAA under the 2008 ozone NAAQS: NOX RACT was approved
for all but one affected source which was conditionally approved
September 22, 2017 at 82 FR 44320 and the VOC RACT was approved at
82 FR 60546.
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6. Reasonably Available Control Measures (RACM)
    The RACM requirement applies to all nonattainment areas that are
required to submit an attainment demonstration. Section 172(c)(1) of
the Act requires SIPs to provide for the implementation of all RACM as
expeditiously as practicable and for attainment of the standard. EPA
interpreted the RACM requirements of 172(c)(1) in the General Preamble
to the Act's 1990 Amendments (April 16, 1992, 57 FR 13498) as imposing
a duty on states to consider all available control measures and to
adopt and implement such measures as are reasonably available for
implementation in the particular nonattainment area. EPA also issued a
memorandum reaffirming its position on this topic, ``Guidance on the
Reasonably Available Control Measures (RACM) Requirement and Attainment
Demonstration Submissions for Ozone Nonattainment Areas,'' John S.
Seitz, Director, Office of Air Quality Planning and Standards, dated
November 30, 1999. In addition, measures available for implementation
in the nonattainment area that could not be implemented on a schedule
that would advance the attainment date in the area would not be
considered by EPA as reasonable to require for implementation. EPA
indicated that a State could reject certain measures as not reasonably
available for various reasons related to local conditions. A state
could include area-specific reasons for rejecting a measure as RACM,
such as the measure would not advance the attainment date,

or was not technologically or economically feasible. Although EPA
encourages areas to implement available RACM measures as potentially
cost-effective methods to achieve emissions reductions in the short
term, EPA does not believe that section 172(c)(1) requires
implementation of potential RACM measures that either require costly
implementation efforts or produce relatively small emissions reductions
that will not be sufficient to allow the area to achieve attainment in
advance of full implementation of all other required measures.
    The TCEQ provided the DFW RACM analysis in Appendix G of the SIP
submittal. Texas evaluated control strategies for NOX and
VOC emissions, from area, point and mobile (on-road and non-road)
sources. The candidate strategies were identified by reviewing existing
control strategies, existing sources of NOX and VOC in the
DFW NAA, and input from stakeholders (full list of measures is provided
in Appendix G of the SIP submittal). As discussed in Chapter 5 of the
SIP submittal and in Appendix D (Conceptual Model for the DFW
Attainment Demonstration SIP Revision for the 2008 Eight-Hour Ozone
Standard), sensitivity analyses and the photochemical modeling indicate
that in the DFW NAA ozone is more responsive to NOX
reductions than VOC reductions. Many measures to reduce VOCs are
already in place, through state and Federal mobile source programs,
including recently approved VOC rules in Wise County (82 FR 60546).
Based on previous modeling by TCEQ and the EPA, only large reductions
of VOC emissions, on the order of 100 tons per day of typical VOCs,
would advance the attainment date in DFW. We were unable to identify
any additional available evaluated measures that cumulatively would
provide 100 tons per day in VOC emissions reductions and thus, advance
the attainment date for the DFW area. For more detail, see the Moderate
Nonattainment Area TSD (MNA TSD).
    The majority of NOX emissions in the DFW NAA come from
mobile sources and industrial processes; emissions of NOX
have been reduced to a large extent with controls on stationary sources
and improved mobile source programs. In addition, the State extended
its NOX RACT rules that were already in place to include
Wise County (81 FR 21747). For more detail, see the MNA TSD.
    We also reviewed whether there were additional available strategies
to reduce NOX emissions from mobile sources. Our analysis
showed that the State SIP already has in place Transportation Control
Measures (TCMs), Voluntary Mobile Emissions Program (VMEP), Texas
Emissions Reductions Plan (TERP), and a motor vehicle I/M program that
EPA has previously approved. Several of the measures in Appendix G are
already covered under the TCMs, VMEP, TERP programs and several other
local measures are being implemented at the airports and by various
cities and others within the DFW NAA.
    In order to advance attainment by a year (i.e., by July 20, 2017),
the State would have to implement any additional control measures
needed for attainment by the beginning of the 2016 ozone season, i.e.,
by March 1, 2016.\23\ While the State was able to revise the SIP with
the new attainment date, its review and analysis of additional RACM
measures did not result in a finding that any additional measures could
be adopted and implemented by March 1, 2016 in order to advance the
attainment date. Based on the RACM analysis, the TCEQ determined that
no potential control measures met the criteria to be considered RACM.
All potential control measures evaluated for stationary sources were
determined not to be RACM due to technological or economic feasibility,
enforceability, adverse impacts, or ability of the measure to advance
attainment of the NAAQS. In general, the State cited to the inability
to advance attainment as the primary determining factor in the RACM
analyses. Because there are no measures that could have been adopted
and implemented by a date that has now passed, we believe the State
properly concluded that additional measures are not RACM.
---------------------------------------------------------------------------

    \23\ EPA signed a final rule on February 13, 2015 that finalized
the revised 2008 ozone attainment dates. (See 80 FR 12264 (March 6,
2015).
---------------------------------------------------------------------------

    EPA interprets the Act's RACM requirement to mean that a measure is
not RACM if it would not advance the attainment date (57 FR 13498,
13560). This interpretation has been upheld. See Sierra Club v. EPA,
294 F.3d 155 (D.C. Cir. 2002) and Sierra Club v. United States EPA, 314
F.3d 735 (5th Cir. 2002). A state must consider all potentially
available measures to determine whether they are reasonably available
for implementation in the area, and whether they would advance the
area's attainment date. The state may reject measures as not meeting
RACM, however, if they would not advance the attainment date, would
cause substantial widespread and long-term adverse impacts, or would be
economically or technologically infeasible. Additionally, potential
measures requiring intensive and costly implementation efforts are not
RACM. Sierra Club v. EPA at 162-163 (D.C. Cir. 2002); Sierra Club v.
EPA, 314 F.3d 735 (5th Cir. 2002); BCCA Appeal Group v. EPA, 355 F.3d
817 (5th Cir. 2003). To demonstrate measures that advance attainment of
the ozone standard, the emission reductions from the measures must
occur no later than the start of the 2016 ozone season--i.e., by March
1, 2016, in order to advance attainment. Because there are no measures
that could have been adopted and implemented by a date that has now
passed, we believe it is appropriate to conclude that additional
measures are not RACM. EPA expects States to prepare a reasoned
justification for rejection of any available control measure. The
resulting available control measures should then be evaluated for
reasonableness considering their technical and economic feasibility,
and whether they will advance attainment. In the case of the DFW SIP,
TCEQ performed an analysis to determine whether all RACM were included
in the SIP. The Fifth Circuit in Sierra Club v. EPA, 314 F.3d 735, 745
(5th Cir. 2002) impressed upon EPA the duty to (1) demonstrate that it
has examined relevant data, and (2) provide a satisfactory explanation
for its rejection of a proposed RACM and why the proposed RACM,
individually and in combination, would not advance the area's
attainment date. See Ober, 243 F.3d at 1195 (quoting American Lung
Ass'n v. EPA, 134 F.3d 388, 392-93 (D.C. Cir. 1998)). EPA reviewed the
State's RACM analysis and believes that the State has included
sufficient documentation concerning the rejection of the available
measures as RACM for the DFW NAA. Further information is found in the
MNA TSD on why we agree with the State that no additional measures are
RACM for the DFW area and therefore the RACM requirement of the Act is
met.
    We propose that any other available evaluated measures are not
reasonably available for the DFW NAA, because they are either
economically or technically infeasible, or would not produce emissions
reductions sufficient to advance the attainment date in the DFW NAA and
therefore, should not be considered RACM.
7. Attainment Motor Vehicle Emission Budgets (MVEBs)
    The ozone attainment demonstration SIP must include MVEBs for
transportation conformity purposes. 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. It
is a process required by section 176(c) of the Act for ensuring that
the effects of emissions from all on-road sources are consistent with
attainment of the standard. EPA's transportation conformity rules at 40
CFR 93 require that transportation plans and related projects result in
emissions that do not exceed the MVEB established in the SIP. The
attainment year established in the DFW ozone attainment demonstration
SIP is the calendar year of the final ozone season for determining
attainment, which is 2017. See 40 CFR 93.118(b).
    The attainment MVEB is the level of total allowable on-road
emissions established by the control strategy implementation plan.
Ozone attainment demonstrations must include the estimates of motor
vehicle VOC and NOX emissions that are consistent with
attainment, which then act as a ceiling for the purposes of determining
whether transportation plans, programs, and projects conform to the
attainment demonstration SIP. In this case, the attainment MVEBs set
the maximum level of on-road emissions that can be produced in 2017,
when considered with emissions from all other sources, which
demonstrate attainment of the 2008 ozone NAAQS.
    The 2017 attainment MVEBs established by this plan and that the EPA
is proposing to incorporate into the DFW SIP are listed in Table 12:

 Table 12--2017 DFW Attainment Motor Vehicle Emissions Budgets (tons per
                                  day)
------------------------------------------------------------------------
                           Pollutant                              2017
------------------------------------------------------------------------
NOX...........................................................    130.77
VOC...........................................................     64.91
------------------------------------------------------------------------

    We found the 2017 attainment MVEBs (also termed transportation
conformity budgets) ``adequate'' and on September 7, 2016, the
availability of these budgets was posted on EPA's website for the
purpose of soliciting public comments. The comment period closed on
October 6, 2016, and we received no comments. On November 8, 2016, we
published the Notice of Adequacy Determination for these attainment
MVEBs (81 FR 78591). Once determined adequate, these attainment MVEBs
must be used in future DFW transportation conformity determinations.
    The attainment budget represents the on-road mobile source
emissions that have been modeled for the attainment demonstration. The
budget reflects all of the on-road control measures in that
demonstration. We believe that the MVEBs are consistent with all
applicable SIP requirements and thus are proposing to approve the 2017
attainment MVEBs into the DFW ozone attainment demonstration SIP. All
future transportation improvement programs, projects and plans for the
DFW NAA will need to show conformity to the budgets in this plan.
8. Contingency Measures Plan
    The general requirements for ozone nonattainment plans under CAA
section 172(c)(9) specify that each nonattainment plan must contain
additional measures that will take effect without further action by the
State or EPA if an area fails to attain the standard by the applicable
date.\24\ The Act does not specify the type of measures, quantity of
emissions reductions required, or how many contingency measures are
needed and thus, EPA has interpreted sections 172 and 182 of the Act in
the General Preamble (57 FR 13498, 13510) to require states with
moderate or above ozone NAAs to include sufficient contingency measures
so that, upon implementation of such measures, additional emissions
reductions of up to 3 percent of the emissions in the adjusted base
year inventory would be achieved in the year following the year in
which the failure has been identified. These could include federal
measures and local measures already scheduled for implementation, since
the CAA does not preclude a state from implementing such measures
before they are triggered. EPA based the 3% recommendation in the
General Preamble on the fact that moderate and above areas are
generally required through the Rate of Progress (ROP)/RFP requirements
to achieve an average of 3% reduction per year until they attain the
NAAQS. The state must specify the type of contingency measures and the
quantity of emissions reductions and show that the measures can be
implemented with no further rulemaking and minimal further action by
the State. See the MNA TSD for a list of applicable guidance documents.
---------------------------------------------------------------------------

    \24\ These provisions do not apply to Marginal NAAs (see section
182(a) of the CAA).
---------------------------------------------------------------------------

    The State submittal includes a contingency measures plan consisting
of the emission reductions from the additional fleet turnover due to
the Federal Motor Vehicle Control Program and Federal non-road mobile
new vehicle certification standards. These measures provide
NOX emission reductions that are in excess of 3 percent of
the NOX emissions in the adjusted base year inventory.\25\
See our MNA TSD for more detail. The fleet turnover measure is a
Federal rule and as such is enforceable by the EPA, the State and the
public. This proposed approval action would make the specified
measures' projected SIP credits enforceable by the EPA and the public.
---------------------------------------------------------------------------

    \25\ The CAA does not preclude a state from implementing such
measures before they are triggered. In Louisiana Envtl. Action
Network v. EPA, 382 F.3d 575 (5th Cir. 2004), the Fifth Circuit held
that Clean Air Act Sec.  7502(c)(9) was ambiguous because it
``neither affirms nor prohibits continuing emissions reductions--
measures which originate prior to the SIP failing, but whose effects
continue to manifest an effect after the plan fails--from being
utilized as a contingency measure.'' The Court agreed with EPA's
interpretation that ``contingency measures'' could include measures
that had already been implemented by a state.
---------------------------------------------------------------------------

    All specified measures are surplus to the reductions in the
attainment demonstration. Finally, the measures are considered
permanent because they continue for as long as the period in which they
are used in the failure-to-attain contingency measures plan. See the
MNA TSD for additional detail.

C. CAA Section 110(l) Analysis

    Section 110(l) of the CAA precludes EPA from approving a revision
of a plan if the revision would interfere with any applicable
requirement concerning attainment and RFP (as defined in section 171 of
the Act), or any other applicable requirement of the CAA. This action
proposes approval of a plan that demonstrates that already adopted
measures both Federal or State will provide levels of emissions
consistent with attaining the ozone NAAQS. Since it is a demonstration,
it will not interfere with any other requirement of the Act. Also in
this action, we are proposing to approve the attainment MVEBs, which
are lower than the previously approved MVEBs for RFP (81 FR 88124), and
the contingency measures plan. The lower attainment demonstration MVEBs
and on-going emission reductions through the contingency measures plan
both provide progress toward attainment and as such do not interfere
with any applicable requirement of the Act.

III. Proposed Action

    We are proposing to approve the August 5, 2016 2008 8-hour ozone
modeling and WOE submitted by the State of Texas because it
demonstrates attainment by the attainment date. We also are proposing
to approve the RACM analysis, the contingency measures plan in the
event of failure to attain the NAAQS by the applicable attainment date,
and the associated Motor Vehicle

Emissions Budgets (MVEBs) for 2017. Finally, we are proposing approval
of the use of TATU's tool and its Unmonitored Area analysis as
acceptable for meeting the recommended evaluation of ozone levels in
the Unmonitored Area analysis for this SIP proposed approval action.

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 Act and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely proposes to approve state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2,
2017) regulatory action because SIP approvals are exempted under
Executive Order 12866;
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
     Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian tribe has
demonstrated that a tribe has jurisdiction. In those areas of Indian
country, the proposed rule does not have tribal implications and will
not impose substantial direct costs on tribal governments or preempt
tribal law as specified by Executive Order 13175 (65 FR 67249, November
9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Nitrogen dioxide, Ozone, Volatile organic compounds.

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

    Dated: April 25, 2018.
Anne Idsal,
Regional Administrator, Region 6.
[FR Doc. 2018-09313 Filed 5-2-18; 8:45 am]
BILLING CODE 6560-50-P


Comment Info: =================

General Comment:Letter concerning the granting of an extension to answer the Refractories MACT ICR. The PDF was deleted in accordance with Agency direction. To review this document, please contact the EPA Docket Center or Air Docket.