[Federal Register Volume 83, Number 103 (Tuesday, May 29, 2018)]
[Proposed Rules]
[Pages 24446-24456]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-11352]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2017-0053; FRL-9978-46--Region 6]


Approval and Promulgation of Implementation Plans; Texas; 
Attainment Demonstration for the Houston-Galveston-Brazoria 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 approval of elements 
of a State Implementation Plan (SIP) revision for the Houston-
Galveston-Brazoria 2008 8-hour ozone National Ambient Air Quality 
Standards (NAAQS) nonattainment area (HGB area). 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 Motor Vehicle Emissions Budgets (MVEBs) for 2017, 
which is the attainment year for the area. EPA is also notifying the 
public of the status of EPA's adequacy determination for these MVEBs 
for the HGB area.

DATES: Written comments must be received on or before June 28, 2018.

ADDRESSES: Submit your comments, identified by Docket No. EPA-R06-OAR-
2017-0053, 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 Carl Young, 214-665-6645, 
[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: Carl Young, 214-665-6645, 
[email protected]. To inspect the hard copy materials, please schedule 
an appointment with Mr. Young or Mr. Bill Deese at 214-665-7253.

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,'' 
``us,'' or ``our'' is used, we mean the EPA.

Table of Contents

I. Background
    A. The 2008 Ozone NAAQS and the HGB Area
    B. CAA and Regulatory Requirements for Ozone Attainment 
Demonstration SIPs
    C. State SIP Submittal
II. The EPA's Evaluation

[[Page 24447]]

    A. Modeling and Attainment Demonstration
    1. Photochemical Grid Model Selection
    2. What time period (episode) did Texas choose to model?
    3. How well did the model perform?
    4. Once the base case is determined to be acceptable, how is the 
modeling used for the attainment demonstration?
    5. What did the results of TCEQ's 2017 future year attainment 
demonstration modeling show?
    6. What are EPA's conclusions of the modeling demonstration?
    7. Weight of evidence
    a. What weight of evidence has been evaluated?
    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.
    8. Is the attainment demonstration approvable?
    B. RACM
    C. Contingency Measures Plan
    D. MVEBs
    E. CAA 110(l) Demonstration
III. Proposed Action
IV. Statutory and Executive Order Reviews

I. Background

A. The 2008 Ozone NAAQS and the HGB Area

    Ground-level ozone is an air pollutant that is formed from the 
reactions of nitrogen oxides (NOx) and volatile organic 
compounds (VOCs) (77 FR 30088, 30089, May 21, 2012). In 2008 we revised 
the 8-hour ozone primary and secondary NAAQS to a level of 0.075 parts 
per million (ppm) to provide increased protection of public health and 
the environment (73 FR 16436, March 27, 2008). The Houston-Galveston-
Brazoria 2008 8-hour ozone NAAQS nonattainment area (HGB area) was 
classified as a ``Marginal'' ozone nonattainment area for the 2008 8-
hour ozone NAAQS (77 FR 30088, May 21, 2012). The area consists of 
Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery 
and Waller counties. The area was initially given an attainment date of 
no later than December 31, 2015 (77 FR 30160, May 21, 2012).
    On December 23, 2014, the D.C. Circuit Court 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 (D.C. Cir. 2014). 
Consistent with the court's decision we modified the attainment 
deadlines for all nonattainment areas for the 2008 ozone NAAQS, and set 
the attainment deadline for all 2008 ozone Marginal nonattainment 
areas, including the HGB area as July 20, 2015 (80 FR 12264, March 6, 
2015). The HGB area qualified for a 1-year extension of the attainment 
deadline and we revised the attainment deadline to July 20, 2016 (81 FR 
26697, May 4, 2016). As the HGB area did not meet the revised 
attainment deadline of July 20, 2016, we reclassified the area to 
``Moderate'' and set a due date for submittal of a revised SIP of 
January 1, 2017 (81 FR 90207, December 14, 2016). The 2008 ozone NAAQS 
attainment deadline for Moderate areas is July 20, 2018 (40 CFR 
51.1103). As an attainment showing is based on the most recent three 
full years of ozone data available, the relevant years for 
demonstrating attainment by the attainment deadline for Moderate areas 
is 2015-2017 and the ``attainment year'' is 2017 (80 FR 12313, 12268).

B. CAA and SIP Requirements for the HGB Area

    When we reclassified the HGB area, we also identified the SIP 
requirements for the area. The requirements being addressed in this 
notice are: (1) Modeling and an attainment demonstration (40 CFR 
51.1108), (2) RACM (40 CFR 51.1112), (3) a contingency measures plan in 
the event of failure to attain the NAAQS by the applicable attainment 
date (CAA sections 172(c)(9) and 182(c)(9)), and (4) attainment MVEBs 
for 2017, which is the attainment year for the HGB area (40 CFR 
93.118(b)).
    For areas classified as Moderate and above, CAA section 
182(b)(1)(A) requires a SIP revision that provides for VOC and 
NOX reductions as necessary to attain the ozone standard by 
the applicable attainment date. For areas classified as Moderate 
nonattainment or above for the 2008 ozone NAAQS, adequacy of an 
attainment demonstration shall be demonstrated by means of a 
photochemical grid model or any other analytical method determined by 
the Administrator to be at least as effective (40 CFR 51.1108).
    We previously approved SIP revisions addressing the following 
requirements for the HGB area: (1) Emissions inventory (80 FR 9204, 
February 20, 2015) and (2) confirmation of provisions addressing 
emissions statements from facilities, new source review emission 
offsets and a basic vehicle inspection and maintenance program (82 FR 
22291, May 15, 2017). In a separate action we are proposing to approve 
the HGB area reasonable further progress (RFP) demonstration and RFP 
milestone failure contingency measures plan (83 FR 17964, April 25, 
2018). We plan to address the HGB area's reasonable available control 
technology demonstration in a separate action.

C. State SIP Submittal

    On December 29, 2016, Texas submitted a SIP revision for the HGB 
area. The SIP revision included a description of how CAA requirements 
for the 2008 ozone NAAQS in the HGB area are met for: (1) Modeling and 
attainment demonstration, (2) RACM, (3) a contingency plan and (4) 
MVEBs. A copy of the SIP revision is available on line at 
www.regulations.gov, Docket number EPA-R06-OAR-2017-0053.

II. The EPA's Evaluation

    We have prepared technical support documents (TSDs) for this 
rulemaking which detail our evaluation. Our TSDs may be accessed online 
at http://www.regulations.gov, Docket No. EPA-R06-OAR-20173-0053.

A. Modeling and Attainment Demonstration

    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 section 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'') \1\, 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 our more detailed evaluation of the attainment demonstration 
(modeling and the Weight of Evidence (WOE) analyses) for the HGB 8-hour 
Ozone Attainment Demonstration see the ``Modeling and Other Analyses 
Attainment Demonstration'' (MOAAD) TSD. The MOAAD TSD also includes a 
complete list of applicable modeling guidance

[[Page 24448]]

documents. These guidance documents provide the overall framework for 
the components of the attainment demonstration, how the modeling and 
other analyses should be conducted, and overall guidance on the 
technical analyses for attainment demonstrations.
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    \1\ A.D. is Attainment Demonstration.
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    As with any predictive tool, there are inherent uncertainties 
associated with photochemical modeling. EPA's guidance recognizes these 
limitations 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 in addition a draft in 2014 was issued for the 2008 8-
hour ozone attainment demonstration procedures. EPA guidance has 
consistently recommended that all attainment demonstrations include 
supplemental analyses, WOE, in addition to 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 was that a WOE 
analysis is specifically recommended to be included as part of any 
attainment demonstration SIP where the modeling results predict Future 
Design Values (FDVs) \2\ ranging from 82 to less than 88 ppb (EPA's 
2005 and 2007 A.D. Guidance documents). 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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    \2\ The design value is the truncated 3-year average of the 
annual fourth highest daily maximum 8-hour average ozone 
concentration (40 CFR 50, Appendix I). Future Design Value is the 
modeling based projected Design Value in the 2017 Future Year.
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    TCEQ submitted the HGB attainment demonstration SIP with 
photochemical modeling and a WOE analyses on December 29, 2016. The 
results of the photochemical modeling and WOE analyses are discussed 
below.
1. Photochemical Grid Model Selection
    Photochemical grid models are 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 6.31 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 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 HGB 
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 2012 ozone 
season (May 1--September 30), so the base case emissions and 
meteorology are for 2012. 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.
    TCEQ chose to use recent versions of Weather Research and 
Forecasting Model (WRF) version 3.7.1 for the meteorological modeling 
for generation of meteorological fields and the Emission Processing 
System (EPS) version 3 for the emission processing to generate the 
necessary meteorological and emission fields to be used in CAMx. TCEQ 
also chose one of the most recent versions of CAMx, version 6.31 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 use of EPS for emissions 
processing and CAMx for photochemical modeling are also one of the two 
predominant modeling platforms used for SIP level modeling and these 
models and versions that TCEQ used. EPA reviewed the models used and 
modeling grids and determined that the model versions used are recent 
versions of the model and the modeling grid is large and sufficiently 
sized to try and minimize the impact of sources outside the grid. Both 
the models used and the modeling grid are acceptable and in accordance 
with 40 CFR part 51 Appendix W Section 5.
2. What time period (episode) did Texas choose to model?
    Texas chose to model May 1st thru September 30th, which is the core 
of the 2012 ozone season (HGB ozone season is January 1st through 
December 31st) and includes a number of historical episodes with 
monitored exceedances. The 2012 ozone season was a period when multiple 
exceedance days occurred with a good variation of meteorological 
conditions that lead to ozone exceedances in the HGB area. Texas 
evaluated other years (2011 and 2013) in their episode selection 
process. The 2011 core ozone season period had a number of exceedances 
but was also complicated by a drought through much of Texas and 
surrounding states that made 2011 less desirable than 2012 which had a 
similar level of

[[Page 24449]]

exceedances. The 2013 core ozone season period had significantly less 
exceedances than 2012. Other years considered either did not have as 
many exceedances or were older episodes so TCEQ chose the 2012 period 
to model.
    We evaluated Texas' 2012 period/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 (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; number 
of days modeled; and whether the time period selected was sufficiently 
representative of the meteorology that drives elevated ozone in the 
area. This evaluation is necessary to insure the model would be 
adequate for evaluating future air quality and any potential control 
strategies. EPA's guidance indicates that all of these items should be 
considered when evaluating available episodes and selecting periods/
episodes to be modeled. EPA believes that the 2012 core ozone period 
(May 1-September 30) includes many exceedance days and is an acceptable 
time period for use in TCEQ's development of the 8-hour ozone 
attainment plan. This period has a number of meteorological conditions 
that are consistent with the conditions that yield high ozone in the 
conceptual model for the HGB area, and was among the episode periods 
evaluated with the highest number of ozone exceedances. In selecting 
periods, it is advantageous to select periods with several exceedance 
days and with multiple monitors exceeding the standard each day when 
possible. This 2012 period was among the best of all the periods 
evaluated when the selection was being conducted. EPA concurs with this 
period. See the MOAAD TSD for further discussion and analysis.
3. 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 which TCEQ performed to evaluate the model's performance. TCEQ 
performed several 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 2014 to 2016, several iterations of the modeling were 
performed by TCEQ incorporating various improvements to the 
meteorological modeling, the 2012 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. TCEQ also 
performed graphical analyses of the meteorology and extensive analyses 
of the photochemical modeling for several base case modeling runs.
    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.\3\ EPA also conducted a review of the model's performance 
in predicting ozone and ozone pre-cursors 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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    \3\ 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, and 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 and 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.\4\ 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 
underestimation bias on some of the higher ozone days. See the MOAAD 
TSD for further analysis.
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    \4\ Id.
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4. 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 evaluated 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 
of this are: (1) Inclusion of electric generating units, or EGUs, that 
were not operating due to temporary shutdown during the base case 
period but were expected to be operating in 2017 and (2) Adjusting the 
hour specific EGUs continuous emissions monitor (CEM) based 
NOX emissions to a typical Ozone season day emission rate). 
This adjusted emission inventory is called the 2012 baseline emission 
inventory. The photochemical model is then executed again to obtain a 
2012 baseline model projection.
    Since the HGB area is classified as a Moderate nonattainment area, 
the attainment date is as expeditiously as practicable but no later 
than July 20, 2018. To meet this deadline, 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's 8-hour ozone modeling 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 (2012). 
The DVs for 2010-2012, 2011-2013, and 2012-2014 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

[[Page 24450]]

(RRF) using a ratio of future and baseline 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 Table 1. 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 (0.075 ppm or 75 ppb) in the baseline, that the 
subset of 10 highest modeled baseline days at each monitor should be 
used for calculating an RRF.\5\ 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 the procedure in the 
2014 Draft A.D. Guidance.
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    \5\ 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 and future 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-2017-0053).
5. What did the results of TCEQ's 2017 future year attainment 
demonstration modeling show?
    The results of the 2012 and 2017 baseline modeling run RRFs and 
model FDV calculations using EPA's 2014 Draft A.D Guidance methods are 
shown in Table 1. Table 1 includes the modeling projections prior to 
evaluating any other modeling sensitivity runs. EPA's full analysis for 
this HGB modeling and our results/conclusions for all the monitors is 
included in the MOAAD TSD.

                                   Table 1--SIP Modeling Projections for 2017
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                                                                     Relative
                   HGB monitor                       2012 BVD        response        2017 FDV        2017 FDV
                                                       (ppb)       factor (RRF)        (ppb)           (ppb)
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Manvel Croix Park--C84..........................              85           0.934           79.41              79
Deer Park--C35..................................           78.33           0.956           74.91              74
Houston East--C1................................              78           0.962           75.06              75
Park Place--C416................................           77.33           0.956           73.89              73
Houston Northwest--C26..........................              80           0.925           74.01              74
Bayland Park--C53...............................           78.67           0.943           74.21              74
Croquet--C409...................................           78.67           0.934           73.49              73
Houston Monroe--C406............................           76.67           0.957            73.4              73
Seabrook Friendship Park--C45...................           76.33           0.948           72.34              72
Houston Texas Ave--C411.........................              75           0.961           72.11              72
Houston Aldine--C8..............................           76.67           0.947           72.59              72
Conroe Relocated--C78...........................              78           0.936           73.04              73
Clinton Drive--C403.............................           74.67           0.968           72.25              72
Houston Westhollow--C410........................           77.67            0.92           71.45              71
Lang--C408......................................           76.33           0.934           71.31              71
Galveston--C1034................................           75.33           0.944           71.15              71
Channelview--C15................................              73           0.959           69.99              70
North Wayside--C405.............................           73.67           0.953           70.23              70
Lynchburg Ferry--C1015..........................              71           0.956           67.88              67
Lake Jackson--C1016.............................           69.33           0.937           64.94              64
----------------------------------------------------------------------------------------------------------------

    The second column is the Base DV for the 2012 period. Using the 
2014 Draft A.D. Guidance, 19 of the 20 HGB area monitors are in 
attainment and one is projected to have a 2017 FDV of 79 ppb.
    The standard attainment test is applied only at regulatory 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.
    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 approved analysis using TATU in previous 
approval of the 2013 HGB 1997 8-hour attainment demonstration (See 
MOAAD TSD for 2013 SIP approval in Docket EPA-R06-OAR-2013-0387 (79 FR 
57, January 2, 2014). We are proposing approval of the use of the TATU 
tool as providing an acceptable UMA 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 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

[[Page 24451]]

flexibility to use other technically supportable tools for the UMA.
    The TATU analysis included in the SIP indicates the maximum in most 
of 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's TATU analysis found two unmonitored areas that 
indicated high values above the standard but neither of these areas are 
higher than the area wide maximum modeled value at Manvel Croix Park 
monitor that is part of the monitored attainment test. One is a small 
unmonitored area on the Harris and Montgomery County border that is 
indicated just above the standard and areas in the Gulf of Mexico. The 
area on the Harris and Montgomery County border is an area between the 
Conroe and NW Harris Co. regulatory monitors but there is also a non-
regulatory monitor (UH WG Jones Forest) that represents some of the 
area between these two regulatory monitors. In comparison to these two 
regulatory monitors the UH WG Jones Forest (UH WG) monitor's recent 4th 
High 8-hour ozone values (2013--preliminary 2017) \6\ have been equal 
or similar to 4th Highs of at least one of these two regulatory 
monitors except in 2016 when the UH WG 4th High was higher. The 2016 UH 
WG 4th High was still several ppb lower than the 2016 HGB maximum 4th 
High indicating that this area including the unmonitored area did not 
represent the area with highest ozone levels in 2016. The UH WG DV 
(non-regulatory) has been within 3 ppb of one of these two regulatory 
monitors and also several ppb less that the HGB maximum DV in recent 
years (2013-preliminary 2017), further indicating that this unmonitored 
area is not an area of significant concern. The other area identified 
was an area over the Gulf of Mexico and parts of Galveston Island where 
there are no meteorology or ozone monitors to evaluate model 
performance/accuracy, the accuracy of the spatial interpolation, and 
the predicted 2017 FDVs, therefore these values are less reliable. 
Additionally, they are not higher than the value at Manvel Croix 
monitor.
---------------------------------------------------------------------------

    \6\ 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.
---------------------------------------------------------------------------

    We agree with TCEQ's analysis finding that the 2 areas identified 
that are outside of the monitored areas are not a concern because they 
are not higher than the value predicted at Manvel Croix and because of 
the issues discussed above. Therefore, the 2017 FDVs are properly 
capturing the geographic locations of the monitored peaks and no 
additional 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.
6. 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 19 out of 20 of the monitors are projected 
to be in attainment in 2017 while one monitor has a 2017 FDV of 79 ppb, 
above the 2008 8-hour Ozone NAAQS (75 ppb). EPA concludes that given 
that 95% of the monitors are in attainment, only one monitor is 
predicted above the standard, and the unmonitored area analysis did not 
show any areas of concern with values higher than the maximum value at 
the Manvel Croix monitor, the overall modeling results are within the 
range \7\ where EPA recommends Weight of Evidence (WOE) be considered 
to determine if the attainment demonstration is approvable.
---------------------------------------------------------------------------

    \7\ 2007 A.D. Guidance indicated within 2-3 ppb for the 1997 8-
hour 84 ppb standard and the 2014 Draft A.D. Guidance indicated the 
model results should be close to the standard without giving an 
exact range. Only one of the 20 value is over with the 2014 Draft 
A.D. Guidance 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.''
---------------------------------------------------------------------------

7. Weight of Evidence
a. Background
    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 recognize potential uncertainty in the modeling 
system and future year projections therefore utilize other supplemental 
information or WOE in deciding if attainment will be achieved. Thus, in 
the HGB case, even though the modeling predicts one out of 20 monitors 
has an FDV above the NAAQS, additional information (WOE) can provide a 
basis to conclude attainment is demonstrated. EPA's guidance indicates 
that several items should be considered 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 that had 
less significant impact on EPA's evaluation. 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?
    TCEQ 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 source apportionment.\8\ TCEQ 
performed source apportionment modeling using 2012 baseline and 2017 
future case modeling databases using the Anthropogenic Precursor 
Culpability Assessment (APCA) tool. \9\ TCEQ provided analysis for 
select monitors that tend to drive the HGB area's DV (Manvel Croix, 
Aldine, and Deer Park) and two of the outer monitors that can have 
higher monitored values and also be more representative of background 
depending on the transport pattern of a given day (Galveston and Conroe 
Relocated). Overall, the APCA indicated that HGB emission sources 
contribute more on the 10 highest days that are used for the RRF and 
FDV calculations than on other days. For these 10 highest days used in 
the modeled attainment test at the higher monitors, the amount of 8-
hour ozone at the monitor in 2017 due to emissions from local HGB 
sources was often in the 15-40 ppb range for Manvel Croix (10-day 
average 28.2 ppb from HGB emissions and 5.35 ppb from rest of Texas 
emissions), 6-48 ppb range for Aldine (10-day average 27.9 ppb from HGB 
emissions and 3.24 ppb from rest of Texas emissions), 7-32 ppb range 
for Deer Park (10-day average 18.1 ppb from HGB emissions and 5.2 ppb 
from rest of Texas emissions). This source apportionment indicates that 
on the

[[Page 24452]]

worst days in the HGB area, local emission reductions and reductions 
within Texas are more beneficial than on other baseline exceedance 
days. This adds a positive WOE that HGB area reductions in mobile on-
road and non-road categories, emission reductions in point source cap 
and trade programs 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.
---------------------------------------------------------------------------

    \8\ Source apportionment allows the tracking of ozone generation 
from regions (such as upwind states or the HGB area, etc.) and also 
by source category (such as on-road, nonroad, EGU, point sources, 
etc.).
    \9\ 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 12 years, based on monitoring data in the HGB Area (2005 
through 2016). TCEQ indicated that the 2015 8-hour ozone DV for the HGB 
nonattainment area is 80 ppb at Manvel Croix, which is in attainment of 
the former 1997 8-hour standard (84 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 
4 ppb per year, and the trend line for the 8-hour ozone DV shows a 
decrease of about 2 ppb per year and reaching attainment of the 75 ppb 
standard in 2017. The 1-hour ozone DVs decreased about 29% from 2005 
through 2016 and the 8-hour ozone DVs decreased about 23% over that 
same time.
    EPA has also supplemented TCEQ's monitoring data analysis with 
additional analysis of 2014-2016 and preliminary 2017 monitoring data 
\10\ (See Tables 2 and 3). There were 20 regulatory monitors in 2012 
(base case year) so the modeling was restricted to FDVs at 20 monitors, 
but the regulatory ambient network has expanded to 21 monitors in 
recent years. The Manvel Croix monitor is located on the south side of 
the urban core, to the west of the Houston Ship Channel. The Aldine 
monitor is located on the north side of the urban core and to the 
northwest of the Houston Ship Channel. One of these two monitors has 
been setting the HGB area DV from 2009 through 2016 years (and 
preliminarily in 2017). The 2016 DV (2014-2016 data) data indicates 
that only three of the 21 regulatory monitors had a DV above the 
standard (Aldine--79 ppb, West Hollow and Galveston--76 ppb). Current 
preliminary 2015-2017 DV data indicates that only five of the 21 
monitors in the HGB area may be above the standard with a preliminary 
2017 DVs of 81 ppb at Aldine, Park Place and Bayland Park with 77 ppb, 
and Westhollow and Lang with 76 ppb.\11\
---------------------------------------------------------------------------

    \10\ 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.
    \11\ Any determination of whether the HGB area has attained the 
2008 ozone NAAQS 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 HGB area has attained 
by the applicable attainment date, given that the attainment date 
has not yet passed and 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 truncated average of 4th 
Highs from 2014-2016. See Table 3 for the 2014-prelminary 2017 4th High 
8-hour values. In 2014 none of the 21 monitors in the HGB area had a 
4th High 8-hour high value above 75 ppb. In 2015 worse meteorology 
(more conducive for formation of ozone) occurred and the 4th high 8-
hour exceedance value monitored at Aldine jumped to 95 ppb with the 
second highest value of 91 ppb at Lang (both 27 ppb higher than their 
2014 value) and 15 other monitors had 4th High 8-hour values greater 
than 75 ppb (17 of the 21 monitors were greater than 75 ppb). In 2016, 
the 4th High 8-hour values went back down and only Westhollow and 
Bayland Park monitors had 4th High 8-hour values greater than 75 ppb 
with 79 ppb and 78 ppb respectively, all other HGB area monitors (19 of 
21) were 75 ppb or less. In the preliminary 2017 data, only 3 of the 21 
monitors had 4th High 8-hour values above 75 ppb (Conroe--79 ppb, 
Clinton Drive--77 ppb, and Manvel Croix--77 ppb) and the other 18 
monitors had values of 75 ppb or less. It is unusual that the 79 ppb at 
the Conroe monitor was the monitor with the preliminary highest 4th 
High in 2017 in the HGB area and the Clinton Drive monitor had a 77 
ppb, as these monitors are not some of the typical High DV monitors in 
HGB. The Conroe and Clinton Drive monitor's 2015 and 2016 DVs are below 
the standard (Clinton Drive 69 ppb both years and Conroe 2015--73 ppb 
and 2016-72 ppb) even with the higher ozone monitored in 2015. 
Considering as recently as 2012, 15 of 20 monitors were violating the 
NAAQS, the area has had large decreases in ozone levels.
    Overall as seen in Tables 2 and 3 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. To assess what might have 
occurred if 2015 hadn't been such a high year we have calculated the 
average of the last two years (2016 and preliminary 2017) 4th Highs and 
all are equal to or below 75 ppb except the Bayland Park monitor with 
76 ppb,\12\ confirming that 2015 is driving the recent DVs because the 
2015 4th Highs are much higher than other recent years (2014, 2016, and 
preliminary 2017).
---------------------------------------------------------------------------

    \12\ Average of 2016 and preliminary 2017 4th Highs: Aldine--74 
ppb, Park Place--68.5 ppb, Westhollow--75 ppb and Lang--69.5 ppb.
---------------------------------------------------------------------------

    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 
conclusion that the general long term trend identified by TCEQ of a 
steady reduction in DV of 2 ppb per year is anticipated to continue. 
Both the individual 4th High monitoring data from 2014, 2016, and 2017 
and the average of the 2016 and preliminary 2017 data are strong WOE. 
The ozone data indicates that emission levels in HGB area 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.

                                  Table 2--HGB Area Monitor DVs (2014-2017) \1\
----------------------------------------------------------------------------------------------------------------
                   HGB monitor                         2014            2015            2016          2017 \1\
----------------------------------------------------------------------------------------------------------------
Baytown Eastpoint...............................              66              68              69              71
Deer Park.......................................              72              69              67              68
Aldine..........................................              72              79              79              81

[[Page 24453]]

 
Clinton Drive...................................              68              69              69              75
Croquet.........................................              75              75              71              71
Monroe..........................................              74              70              65              63
NW Harris Co....................................              75              73              69              73
Westhollow......................................              76              75              76              76
Lang............................................              74              78              74              76
Wayside.........................................              69              70              67              69
Mae Drive (Houston East)........................              72              74              73              75
Bayland Park....................................              75              76              75              77
Seabrook........................................              72              71              70              71
Channelview.....................................              67              68              68              69
Lynchburg.......................................              66              67              65              61
Park Place......................................              74              77              72              74
Galveston.......................................              72              73              76              77
Conroe..........................................              76              73              72              74
Manvel..........................................              80              80              75              77
Lake Jackson....................................              66              64              64              65
----------------------------------------------------------------------------------------------------------------
\1\ 2017 DV and 4th High 8-hour values are preliminary data.


                        Table 3--HGB Area Monitor 4th High 8-hour Values (2014-2017) \1\
----------------------------------------------------------------------------------------------------------------
                                                                                                   2016-2017 \1\
           HGB monitor                 2014            2015            2016          2017 \1\          avg.
----------------------------------------------------------------------------------------------------------------
Baytown Eastpoint...............              67              77              65              73              69
Deer Park.......................              63              77              62              66              64
Aldine..........................              68              95              74              74              74
Clinton Drive...................              58              84              65              77              71
Croquet.........................              67              79              67              67              67
Monroe..........................              65              73              57              59              58
NW Harris Co....................              63              78              67              74            70.5
Westhollow......................              70              79              79              71              75
Lang............................              64              91              69              70            69.5
Wayside.........................              62              78              62              68              65
Mae Drive (Houston East)........              66              88              67              70            68.5
Bayland Park....................              67              80              78              74              76
Seabrook........................              65              83              64              67            65.5
Channelview.....................              64              81              61              65              63
Lynchburg.......................              59              79              59              46            52.5
Park Place......................              66              87              65              72            68.5
Galveston.......................              71              84              74              73            73.5
Conroe..........................              72              73              71              79              75
Manvel Croix....................              71              86              69              77              73
Lake Jackson....................              61              65              66              65            65.5
----------------------------------------------------------------------------------------------------------------
\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 2012 period to fit the range of days and meteorological cycles 
that yield high ozone in HGB, meteorological transport clustering, 
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 December 29, 2016 
SIP submittal and discussed in the MOAAD TSD.
d. Other WOE Items From Texas Not Currently Quantified With Modeling: 
Additional Programs/Reductions, etc.
    Refinery Consent Decrees--Texas noted that EPA's existing and 
continued efforts are resulting in many consent decrees that obtain 
reductions at refineries across the U.S. and approximately 14% of the 
nation's refining capacity is in the HGB area. Texas indicted that 
these consent decrees are yielding reductions in flaring operations, 
better monitoring of emissions using continuous emission monitors or 
predictive emission monitoring systems, and other emission reductions 
from large emissions sources at these facilities. Texas indicated that 
not all of these emissions have been quantified and included in the 
model, so some emission reductions required by these actions provide 
positive WOE.
    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 HGB area. Texas also noted that since the 
inception of TERP in 2001 through August 2016, over $1,013 million 
dollars have been spent within the state through TERP and the Diesel 
Emission Reduction Incentive Program (DERI) that has resulted in 
171,945 tons of NOX

[[Page 24454]]

reductions in Texas by 2016. TCEQ also noted that over $423.6 million 
in DERI grants have been awarded to projects in the HGB area through 
2016 resulting with a projected NOX reduction of 75,739 tons 
that is also estimated as 14.1 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. In HGB area between December 12, 2007 and May 31, 
2016, the program repaired 19,297 and retired and replaced 29,716 
vehicles at a cost of $98.1 million. Participating HGB area counties 
were allocated approximately $20.1 million per year for LIRAP for FYs 
2016 and 2017. This is an increase of approximately $17.5 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 $1.9 
million per year over previous biennium. These LIP benefits were not 
modeled but the reductions and future reductions do provide positive 
WOE.
    Local Initiatives--TCEQ indicated that there is an assortment of 
locally implemented strategies in the HGB 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--Blue Skyway and Smartway programs encourage 
voluntary emission reductions in fleets by supporting reduced fuel 
combustion and use of alternative fuels. Since these are voluntary 
measures and reporting/verification is not a requirement, the amount of 
NOX and VOC reductions that may occur are not easily 
quantifiable, but they do provide positive WOE from this sector.
8. Is the 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 to 
demonstrate attainment of the standard by the attainment date. Although 
the modeled attainment test is not met at one of the 20 HGB monitors 
because one of the monitors was projected to remain above the standard, 
consistent with our A.D. guidance, TCEQ submitted a WOE analysis that 
supports that the emission levels in the area are consistent with 
attainment. This WOE analysis provides additional scientific analyses 
based on identification of emission reductions not captured in the 
modeling, monitoring trends, recent monitoring data (EPA included more 
recent monitoring data since the SIP submission) and other modeling 
analyses. The average of the 2016 and preliminary 2017 4th High Data 
indicates all monitors but one are at or below the standard. This 
includes the Manvel Croix monitor, the one monitor projected in the 
modeling to be over the standard, with a value of 73 ppb. The one 
monitor, which the 2016-2017 average is above standard is just 1 ppb 
over. The combination of the modeling and the WOE indicate that recent 
emission levels are consistent with attainment of the standard and 
demonstrate attainment by the attainment date. We are therefore 
proposing to approve the attainment demonstration submitted in the 
December 29, 2016 submittal.

B. RACM

    A demonstration is required that all RACM necessary to demonstrate 
attainment as expeditiously as practicable has been adopted (CAA 
section 172(c)(1) and 40 CF 51.1112(c)). We consider a control measure 
to be necessary under the RACM requirement if it: (1) Is 
technologically feasible, (2) is economically feasible, (3) does not 
cause substantial widespread and long-term adverse impacts, (4) is not 
absurd, unenforceable, or impracticable and (5) can advance the 
attainment date by at least a year (57 FR 13498, 13560, April 16, 1992; 
74 FR 2945, 2951, January 16, 2009; and 78 FR 55037, 55044, September 
9, 2013).
    Texas identified and analyzed whether potential control measures 
would be considered a RACM measure. Texas determined that none of these 
measures meet the five RACM criteria. We reviewed the RACM analysis and 
propose to approve the Texas demonstration that the HGB area has met 
the RACM requirement. We note that to advance the attainment date by at 
least a year (to July 20, 2017) additional control measures would need 
to be implemented at the beginning of 2016. Given the requirement for a 
SIP revision was published December 14, 2016, it is not feasible that 
additional measures could be implemented at the beginning of 2016.

C. Contingency Measures Plan

    CAA section 172(c)(9) require contingency measures to be 
implemented in the event of failure to attain the NAAQS by the 
applicable attainment date or if the area fails to make reasonable 
further progress. These contingency measures must be fully adopted 
rules or measures which are ready for implementation quickly upon 
failure to meet attainment. Implementation of the contingency measures 
should provide additional emissions reductions of up to 3% of the base 
year inventory (or lesser percentage that will cure the identified 
failure). The reductions are to be achieved in the year following the 
year in which the failure has been identified (57 FR 13498, 13510-12, 
April 16, 1992). The base year inventory is that specified by CAA 
section 182(b)(1)(B) and 40 CFR 51.1115.
    The Texas contingency measures plan is based on (1) a 2011 base 
year inventory, (2) a 2% NOX emissions reduction and a 1% 
VOC emissions reduction and (3) reductions from 2017 to 2018 due to 
Federal control measures for on-road motor vehicles. Texas used the EPA 
MOVES2014a mobile source

[[Page 24455]]

emissions estimation model to calculate the on-road emissions 
reductions.
    Table 4 is a summary of the Texas contingency measures plan for the 
HGB area. As Texas has demonstrated that the base year emissions will 
be reduced by at least 3% from 2017 to 2018, we propose to approve the 
HGB contingency measures plan.

      Table 4--Contingency Measures Demonstration for the HGB Area
------------------------------------------------------------------------
                                          NOX  emissions
               Description                (tons per day)  VOC  emissions
                                                          (tons per day)
------------------------------------------------------------------------
Base Year Emissions Inventory...........          459.94          531.40
Percent for Contingency Calculation.....              2%              1%
(Total of 3%)...........................
Required 2017 to 2018 Contingency                   9.20            5.31
 Reductions.............................
Total 2017 to 2018 Contingency                     24.35            8.78
 Reductions due to Federal Measures for
 On-road Motor Vehicles.................
Contingency Excess (+) or Shortfall (-).          +15.15           +3.47
------------------------------------------------------------------------

D. MVEBs

    MVEBs are required for ozone attainment demonstrations to ensure 
that transportation plans, transportation improvement programs and 
federally supported highway and transit projects are consistent with 
(``conform to'') the purpose of the 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 relevant NAAQS or interim reductions and milestones 
(81 FR 12264, 12283-84, March 6, 2015). The SIP included attainment 
NOX and VOC MVEBs for the 2017 attainment year (table 5). 
The MVEBs represents the maximum level of on-road emissions of 
NOX and VOC that can be produced in 2017--when considered 
with emissions from all other sources--which demonstrate attainment of 
the NAAQS. As our review found that the 2017 MVEBs are consistent with 
the emissions inventory and control measures that we are proposing 
provide for attainment, we propose to approve the MVEBs.

                         Table 5--2017 HGB MVEBs
------------------------------------------------------------------------
                                                          Summer weekday
                        Pollutant                            emissions
                                                          (tons per day)
------------------------------------------------------------------------
NOX.....................................................           95.56
VOC.....................................................           54.40
------------------------------------------------------------------------

    When reviewing submitted ``control strategy'' SIPs containing 
MVEBs, EPA may affirmatively find the MVEBs contained therein adequate 
for use in determining transportation conformity. EPA's substantive 
criteria for determining adequacy of a MVEB are set out in 40 CFR 
93.118(e)(4). EPA is evaluating the adequacy of the submitted MVEBs in 
parallel to this proposed approval action on the attainment 
demonstration. The NOX and VOC MVEBs for the HGB area opened 
for public comment on EPA's adequacy website on May 17, 2018, found at: 
https://www.epa.gov/state-and-local-transportation/state-implementation-plans-sip-submissions-currently-under-epa. The adequacy 
comment period for these MVEBs will close on June 18, 2018.
    Once EPA affirmatively finds the submitted MVEBs are adequate for 
transportation conformity purposes, these MVEBs must be used by state 
and Federal agencies in determining whether proposed transportation 
projects conform to the SIP as required by section 176(c) of the CAA. 
Within 24 months from the effective date of EPA's adequacy 
determination for the MVEBs or the publication date for the final rule 
for this action, whichever is earlier, the transportation partners will 
need to demonstrate conformity to the new NOX and VOC MVEBs 
pursuant to 40 CFR 93.104(e)(3).

E. CAA 110(l) Demonstration

    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 MVEBs proposed to be approved for RFP (83 FR 17964, 
April 25, 2018), 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 elements of a HGB area SIP revision for 
the 2008 8-hour ozone NAAQS. Specifically, we are proposing approval of 
the attainment demonstration, a RACM analysis, the contingency measures 
plan in the event of failure to attain the NAAQS by the applicable 
attainment date, and NOX and VOC MVEBs for 2017. 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. 
Further, as part of today's action, we are describing the status of our 
adequacy determination for the NOX and VOC MVEBs for 2017 in 
accordance with 40 CFR 93.118(f)(2). Within 24 months from the 
effective date of our adequacy determination for the MVEBs or the 
publication date for a final rule approving the MVEBs, whichever is 
earlier, the transportation partners will need to demonstrate 
conformity to the new NOX and VOC MVEBs pursuant to 40 CFR 
93.104(e)(3).

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:

[[Page 24456]]

     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, Ozone.

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

    Dated: May 22, 2018.
Anne Idsal,
Regional Administrator, Region 6.
[FR Doc. 2018-11352 Filed 5-25-18; 8:45 am]
 BILLING CODE 6560-50-P