2016-22564. Approval and Promulgation of Air Quality Implementation Plans; Texas; Reasonable Further Progress Plan and Motor Vehicle Emissions Budgets for the Dallas/Fort Worth 2008 Ozone Nonattainment Area

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing to approve revisions to the Dallas/Fort Worth (DFW) Texas Reasonable Further Progress (RFP) State Implementation Plan (SIP) for the DFW moderate nonattainment area for the 2008 ozone National Ambient Air Quality Standard (NAAQS or standard). The SIP revision was submitted to the EPA on July 10, 2015 and supplemented on April 22, 2016. We also are proposing to approve revisions to the 2011 base year emissions inventory for the DFW moderate nonattainment area for the 2008 ozone NAAQS standard, the 2017 transportation conformity motor vehicle emissions budgets, and the required contingency measures for failure to meet RFP. This action is being taken under the Clean Air Act (CAA).

DATES:

Written comments must be received on or before October 20, 2016.

ADDRESSES:

Submit your comments, identified by Docket No. [EPA-R06-OAR-2015-0495], at http://www.regulations.gov or via email to [e-mail]. 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 Ms. Wendy Jacques, [phone], [e-mail]. 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:

Ms. Wendy Jacques, [phone], [e-mail]. To inspect the hard copy materials, please schedule an appointment with Ms. Wendy Jacques or Mr. Bill Deese at [phone].

SUPPLEMENTARY INFORMATION:

Throughout this document, “we,” “us,” and “our” mean the EPA.

I. Background

The EPA is proposing to approve revisions to the Texas SIP, submitted to EPA on July 10, 2015 and supplemented on April 22, 2016 to meet certain requirements under section 182(b) of the CAA for the DFW Moderate nonattainment area (NAA) under the 2008 ozone standard. We are proposing to approve the DFW RFP SIP that includes the RFP plan, contingency measures for failure to meet RFP milestone requirements, and the 2017 transportation conformity motor vehicle emissions budgets (MVEBs). We are also proposing to approve the 2011 base year emissions inventory (EI).

On March 12, 2008, the EPA promulgated a revised 8-hour ozone standard of 0.075 parts per million (ppm) ^[1] and on April 30, 2012, the EPA designated and classified the DFW area (consisting of Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant and Wise counties) ^[2] as a Moderate NAA under the 2008 ozone standard with an attainment date of July 20, 2018.^[3] Accordingly, the Texas Commission on Environmental Quality (TCEQ) was required to submit revisions to the DFW SIP to meet requirements under section 182(b) of the CAA for the Moderate NAA. A brief history of the DFW area under the prior 1-hour and 1997 8-hour ozone standards, as well as additional background information, is provided in the Technical Support Document (TSD), which is in the docket for this rulemaking.

A. The Reasonable Further Progress (RFP) Plan

The CAA requires that areas designated as nonattainment for ozone and classified as Moderate or worse demonstrate RFP in reducing emissions of ozone precursors (nitrogen oxides or NO_X and volatile organic compounds or VOCs) ^[4] over a specific period of time. The RFP plan generally is designed to achieve progress toward meeting the ozone NAAQS through annual reductions in emissions of NO_X and/or VOCs. In our final rule to implement the 2008 ozone standard (referred to as the SIP Requirements Rule or SRR) we addressed, among other things, the RFP requirements as they apply to areas designated nonattainment and classified as Moderate for the 2008 ozone standard. For the purposes of the 2008 ozone NAAQS, the EPA in the SRR interpreted CAA section 182(b)(1)(A)(ii) to require such Moderate areas to obtain 15 percent ozone precursor emission reductions over the first 6 years after the baseline year for the 2008 ozone NAAQS (see 80 FR 12264, March 6, 2015 and 40 CFR 51.1110).

RFP plans must also include a MVEB, which provides the allowable on-road mobile emissions an area can produce and continue to demonstrate RFP. The State's RFP submittal included MVEBs for the DFW area for the year 2017 (see Chapter 5 of the State's submittal and page 13 of our TSD). The MVEBs are discussed in detail later in this rulemaking.

Pursuant to section 172(c)(9) of the CAA, nonattainment plan provisions must also provide for the implementation of contingency measures, that is, specific measures to be undertaken if a nonattainment area fails to make reasonable further progress, or to attain the national primary ambient air quality standard by the applicable attainment date. Such contingency measures shall take effect without further action by the State or EPA, which include additional controls that would be implemented if the area fails to reach, in this case, its RFP milestones. While the CAA does not specify the type of measures or quantity of emissions reductions required, EPA has interpreted the CAA to mean that implementation of these contingency measures would provide additional emissions reductions of up to 3% of the adjusted base year inventory (or a lesser percentage that will make up the identified shortfall) in the year following the RFP milestone year. For more information on contingency measures, see the April 16, 1992 General Preamble (57 FR 13498, 13510) and the SRR (80 FR 12264, 12285). The State provided emissions reductions in excess of those needed for RFP as contingency measures (see Chapter 4, pages 15-17 of the State's submittal and Tables 6 and 7 in our TSD). The submitted contingency measures include, but are not limited to, (1) mobile source emission reductions addressing engine and fuel rules; and (2) fleet turnover.

In addition, section 182(a)(1) of the CAA requires an inventory of actual emissions from all sources of relevant pollutants in the nonattainment area. Such emissions inventories are used, among other things, in the calculations concerning RFP in such areas. In the SRR, the EPA recommended using 2011 as the base year emission inventory. Texas submitted a revised 2011 base year inventory for area and mobile source emissions in the ten-county NAA to meet this requirement.

II. The EPA's Evaluation

The SIP revision submitted by the TCEQ on July 10, 2015 and supplemented on April 22, 2016 includes: (1) A revised 2011 base year EI for area and mobile sources; (2) the RFP plan (which must demonstrate NO_X and/or VOC emissions reductions of at least fifteen percent through 2017 for nine of the ten counties and VOC-only emissions reductions for Wise County); (3) contingency measures to be implemented in 2018 if the 2017 RFP target is not met; and (4) the MVEBs for 2017.^[5]

We reviewed the submittal for consistency with the requirements of the CAA, EPA regulations, and EPA guidance. A summary of our analysis and findings are provided below. For a more detailed discussion of our evaluation, please see our TSD.

A. The DFW Base Year Emissions Inventory

An emissions inventory is a comprehensive, accurate, and current inventory of actual emission from all sources. It is required by sections 172(c)(3) and 182(b)(1) of the CAA that require that nonattainment plan provisions include an inventory of NO_X and VOC emissions from all sources in the nonattainment area. The EPA previously approved the 2011 base year inventory (see 80 FR 9204, February 20, 2015). Since that submittal, several improvements have been made, including, but not limited to, improvements to the models used to calculate the mobile source categories within the inventory. Because of these refinements, revisions to more accurately reflect the EI were made by the TCEQ. We have determined that the revised inventory was developed in accordance with EPA guidance and regulations ^[6] and therefore, we propose to approve the revised 2011 base year EI. For reference, the previously approved base year EI (80 FR 9204) is provided in Table 1, reported in tons per day (tpd), along with the revised 2011 base year EI, also reported in tpd. Details on how each of the emissions categories was revised and emissions totals for each county are included in the TSD.

Table 1—Previously Approved (80 FR 9204) and Revised RFP Base Year EIs

Source type	NOX		VOC
	Approved at 80 FR 9204	Submitted revisions *	Approved at 80 FR 9204	Submitted revisions *
2011 Base Year Inventory for the DFW Ten-County Nonattainment Area (tpd)
Point	39.95	39.95	29.80	29.80
Area	42.64	50.98	292.49	291.31
Non-road Mobile	120.61	116.95	55.00	54.63
On-road Mobile	238.87	241.13	98.36	104.12
Total	442.07	449.01	475.65	479.86
* Submitted to EPA by the TCEQ on July 10, 2015.

B. The DFW RFP SIP Revision

1. The Adjusted Base Year Inventory and RFP Target Levels for 2017 and 2018

The 2011 base year EI is the starting point for calculating RFP. The “adjusted” emissions are what we would expect to see if the on-road fleet did not implement the low Reid Vapor Pressure (RVP) gasoline and pre-1990 automobile emission controls. Such controls are not creditable under section 182(b)(1)(D) of the CAA, but are no longer required to be calculated for exclusion in RFP analyses because the Administrator determined that due to the passage of time the effect of these exclusions would be de minimis (40 CFR 51.1110). The State has chosen these non-creditable reductions to represent a more accurate accounting, which is acceptable. The result, after subtracting the non-creditable reductions, is known as the adjusted base year inventory. The RFP target levels and emissions reductions required to meet those targets are calculated from the adjusted base year inventory.

To achieve the RFP target levels, section 182(c)(2)(B) of the CAA allows for substitution of NO_X emission reductions for VOC emission reductions in certain circumstances. See 80 FR 12264, 12271 and 40 CFR 51.1110.^[7] For example, the DFW ten-county NAA includes nine counties that have already met the 15 percent emission reduction requirement for VOC under the 1-hour ozone NAAQS (Collin, Dallas, Denton and Tarrant, see 70 FR 18993) and under the 1997 ozone NAAQS (Ellis, Johnson, Kaufman, Parker and Rockwall, see 73 FR 58475). Therefore, these nine counties may rely upon NO_X and VOC emissions reductions to achieve the RFP target levels. Wise County however, must meet the 15 percent VOC emission reduction requirement because this is its first time to be covered under the ozone nonattainment SIP requirements. This also means that these VOC emission reductions are calculated separately from the other nine counties (see the TSD for a more detailed explanation). The RFP submittal provides emission reductions of NO_X and VOC whose combined total is 15 percent for nine of the ten counties (all but Wise County). As explained in more detail in the State's April 22, 2016 “Technical Supplement to the 2008 Ozone DFW RFP SIP Revision,” the TCEQ provided a technical supplement to EPA to correct the 2017 RFP demonstration for Wise County as well as a corrected RFP spreadsheet that removed the transfer of VOC reductions to Wise County and credits emissions reductions from drilling rig controls that were available but not credited in its July 10, 2015 submittal. The technical supplement shows that Wise County meets the 15% VOC-only reduction requirement from the 2011 base year through the 2017 attainment year based solely on reductions from within Wise County. All the data used to meet this requirement within Wise County was included in the original submitted SIP RFP revision but was not used in the RFP calculations because TCEQ did not think it was needed at that time.

Tables 2 and 3 provide an accounting of the emissions targets through 2017. Table 2 shows the calculations and reductions required for nine of the ten counties (all but Wise County) to achieve RFP and Table 3 provides the calculations and reductions required for Wise County to achieve RFP.^[8]

Table 2—Calculation of NO_X and VOC Reductions for Nine Counties (All but Wise County) Through 2017

[tpd]

Description	NOX	VOC
a. 2011 Emissions Inventory	414.52	445.79
b. Non-creditable on-road reductions 2011-2017	2.87	−4.45
c. 2017 Adjusted Base Year EI (row a minus row b)	411.65	450.24
d. Percent of NOX and VOC to meet 15% reduction	10.0%	5.0%
e. 15% NOX and VOC reduction, 2011-2017 [(row c) × (row d)]	41.17	22.51
f. 2017 Target Level of Emission (row c minus row e)	370.48	427.73

Table 3—Calculation of NO_X and VOC Reductions for Wise County Through 2017

[tpd]

Description	NOX	VOC
a. 2011 Emissions Inventory	34.49	34.07
b. Non-creditable on-road reductions, 2011-2017	0.21	−0.08
c. 2017 Adjusted Base Year EI (row a minus row b)	34.28	34.15
d. Percent of NOX and VOC to meet 15% reduction	N/A	15.0%
e. 15% VOC reduction, through 2017 [(row d) × (row e)]	N/A	5.12
f. 2017 Target Level of Emissions (row c minus row e)	34.28	29.03

We find the calculations are mathematically correct and approvable.

2. The Projected Emissions Inventories and How the Required Emissions Reductions Are Achieved

Section 182(b)(1)(A) of the CAA requires that States provide sufficient control measures in their RFP plans to offset growth in emissions. To do this, the State must estimate the amount of growth that will occur between 2011 and the end of 2017. The State's approach is consistent with our guidelines in estimating the growth in emissions.^[9] The projections of growth are labeled as the “Uncontrolled Emissions” for 2017 under (b) in the table below and are described in greater detail in our TSD.^[10]

Texas then estimated emission reductions from State and federal control measures in place in 2011 and expected to continue through 2017. The list of State and federal control measures relied upon is provided in our TSD and includes, but is not limited to, on-road and non-road mobile source emission reductions from engine and fuel rules and fleet turnover.^[11] Texas appropriately estimated the emission reductions from controls in place in 2011 and appropriately projected the emission reductions out to 2017 (see more details in the TSD) that are found on line (c) in Table 4. Texas then applied these current and future estimated reductions to the appropriate uncontrolled inventories. The results are the projected emissions listed in line “d” in Tables 4 and 5 of this proposal. The total amount of VOC and NO_X emissions in the controlled inventories for 2017 must be equal to or less than the corresponding RFP target inventories to demonstrate RFP.

Table 4—Summary of RFP Demonstration for the DFW Area Through 2017

[tpd]

Description	NOX	VOC	NOX	VOC
	9 Counties		Wise County
a. 2017 Target	370.48	427.73	34.28	29.03
b. 2017 Uncontrolled Emissions	1139.93	830.38	49.33	34.68
c. Projected Emission Reductions through 2017	839.50	428.85	20.29	5.73
d. Projected Emissions after Reductions (b-c)	300.43	401.53	29.04	28.95
2017 RFP Targets	370.48	427.73	34.28	29.03
RFP Met?	yes	yes	yes	yes
Surplus or (shortfall)	70.05	26.20	5.24	0.08

As shown in Table 4, the projected emissions in line “d” for NO_X and VOC for all counties in the DFW ten-county NAA are less than the RFP targets and therefore meet the RFP requirement (target or milestone) for 2017. Therefore, the EPA is proposing that the emissions reductions projected for 2017 are sufficient to meet the 2017 RFP targets.

3. The RFP Contingency Measures

Section 172(c)(9) of the CAA requires that an RFP plan for a Moderate nonattainment area include contingency measures, which are additional controls to be implemented if the area fails to make reasonable further progress, i.e., fails to reach the 2017 RFP target. Contingency measures are intended to achieve reductions over and beyond those relied on in the RFP demonstration to achieve the 2017 milestones and could include federal and State measures already scheduled for implementation. The CAA does not preclude a State from implementing such measures before they are triggered. Texas used federal and State measures expected to be implemented to meet the contingency measure requirement for the RFP. These measures provide reductions through 2018 that are in excess of those needed to achieve the 2017 RFP milestones. Tables 5 and 6 provide an accounting of the emissions targets through 2018. Table 5 shows the calculations and reductions required to meet the contingency requirement for nine of the ten counties (all but Wise County) and Table 6 provides the calculations and reductions required for Wise County to meet the contingency requirement. Regarding the content of the contingency measures, the 3 percent emissions reductions for contingency measures may be based entirely on NO_X controls if the area has completed the initial 15 percent rate-of-progress VOC reduction required by CAA section 182(b)(1)(A)(i) ^[12] and the State showed that NO_X substitution would be most effective in bringing the area into attainment. The State demonstrated that the DFW rural and northwestern monitors located on the periphery of the DFW area have continued to measure NO_X-limited conditions, meaning that ozone formation is more sensitive to the amount of NO_X present in the atmosphere. The State also shows that the DFW monitors in the urban core measure more transitional conditions (not strongly limited by either NO_X or VOC) and controlling either VOC or NO_X emissions in these regions would reduce ozone concentrations.^[13] For the RFP contingency measures, the State chose a mix of NO_X and VOC emission reductions for all but Wise County and chose just NO_X emission reductions for Wise County. The State chose to separately account for contingency measures for Wise County and to be consistent, we have done the same.

Table 5—Demonstration of 2018 Contingency Measures (tpd) for Nine Counties

[All but Wise County]

Description	NOX	VOC
A. 2017 Adjusted Base Year EI	411.65	450.24
B. Percent of NOX and VOC to meet 3% contingency	2%	1%
C. Required reduction to provide contingency (A × B)	8.23	4.50
D. Reduction to meet RFP in 2017 (Table 2, line e)	41.17	22.51
E. 2018 on-road mobile non-creditable reductions	0.58	0.23
F. 2018 Target Level of Emissions (line A-C-D-E)	361.67	423.00
Excess reductions to meet contingency requirement
G. 2018 Uncontrolled Emissions	1157.47	833.75
H. Total Reductions Projected through 2018	878.29	445.64
J. Projected emissions after reductions (line G minus line H)	279.18	388.11
Add line C	8.23	4.50
K. Projected emissions, accounting for contingency measures	287.41	392.61
Total surplus or shortfall
Line K is less than line F. Subtract line K from line F for surplus	74.26	30.39
Is the contingency measure requirement met?	Yes	Yes

Table 6—Demonstration of 2018 Contingency Measures for Wise County

[tpd]

Description	NOX	VOC
A. 2017 Adjusted Base Year EI	34.28	34.15
B. Percent of NOX and VOC to meet 3% contingency	3%
C. Required reduction to provide contingency (A × B)	1.03
D. Reduction to meet RFP in 2017	0	5.12
E. 2018 on-road mobile non-creditable reductions	0	0
F. 2018 Target Level of Emissions (line A-C-D-E)	33.25	29.03
Excess reductions to meet contingency requirement
G. 2018 Uncontrolled Emissions	46.24	29.71
H. Total Reductions Projected through 2018	20.95	5.97
J. Projected emissions after reductions (line G minus line H)	25.29	23.74
Add line C	1.03	0
K. Projected emissions, accounting for contingency measures	26.32	23.74
Total surplus or shortfall
Line K is less than line F. Subtract line K from line F for surplus	6.93	5.29
Is the contingency measure requirement met?	Yes

As shown in Tables 5 and 6, the NO_X and VOC emission reductions through 2018 are sufficient to provide at least 3 percent emission reductions and thus we find that the contingency measures requirement are met for RFP.

4. The Motor Vehicle Emissions Budgets (MVEBs)

According to the transportation conformity rule, an RFP plan must establish MVEBs for transportation conformity purposes. See 40 CFR 93.118(b)(1)(i). The MVEB is the mechanism to ensure that future transportation activities will not produce new air quality violations, worsen existing violations, delay reaching RFP milestones, or delay timely attainment of the NAAQS. A MVEB establishes the maximum amount of emissions allowed in the SIP for on-road motor vehicles.

As part of the July 10, 2015, SIP revision submittal, the TCEQ included VOC and NO_X MVEBs for 2017; these budgets are provided in Table 7. For the budgets to be approvable, they must meet, at a minimum, EPA's adequacy criteria (40 CFR 93.118(e)(4)). The availability of these budgets was posted on our Web site on August 25, 2015, for the purpose of soliciting public comments on their adequacy. The comment period closed on September 24, 2015, and we received no comments. On January 11, 2016, we published the Notice of Adequacy Determination for these MVEBs (81 FR 1184). As a result of such adequacy determination, 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. The adequacy determination represents a preliminary finding by EPA of the acceptability of the MVEBs. Today we are proposing that these MVEBs are fully consistent with RFP, as it sets the allowable on-road mobile emissions the DFW area can produce and continue to demonstrate RFP.

Table 7—RFP Motor Vehicle Emissions Budgets for DFW (tpd)

Year	NOX	VOC
2017	148.36	77.18

III. Proposed Action

The EPA is proposing to approve revisions to the Texas SIP to meet certain requirements under section 182(b) of the CAA for the DFW Moderate nonattainment area under the 2008 ozone standard that were submitted to EPA on July 10, 2015 and supplemented on April 22, 2016. We are proposing to approve the revised base year emission inventory, the RFP plan, the 2017 MVEBs; and RFP contingency measures.

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);
• 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, 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
• Intergovernmental relations
• Ozone
• Reporting and recordkeeping requirements
• Volatile organic compounds

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

Dated: September 14, 2016.

Ron Curry,

Regional Administrator, Region 6.

Footnotes

1.  See 73 FR 16436, published March 27, 2008. In this action we refer to the 2008 8-hour ozone standard as “the 2008 ozone NAAQS” or “the 2008 ozone standard.”

2.  See 77 FR 30088, published May 21, 2012. We refer to the DFW nonattainment area for the 2008 ozone standard as “the 10-county NAA.”

3.  See 80 FR 12264, published March 6, 2015.

4.  For additional information on ozone, please see the TSD and visit www.epa.gov/​groundlevelozone.

5.  A technical supplement to the RFP submittal was provided by the TCEQ on April 22, 2016, showing how Wise County meets the 15% emission reduction requirement described elsewhere in this proposal. The data provided in the technical supplement was included in the July 10, 2015 SIP submittal, but was not used in the State's calculations because the TCEQ calculated the 15% emission reduction using all 10 counties and did not realize the requirement for Wise County to meet a 15% emission reduction by itself. For more detail, see our TSD and the TCEQ's April 22, 2016 technical supplement in the docket for this rulemaking.

6.  Under sections 172(c)(3) and 182(a)(1) of the CAA, states are required to submit EI information for all relevant sources for areas that are designated nonattainment for any of the NAAQS. See also https://www.epa.gov/​air-emissions-inventories for more information on air emission inventories, including regulations and EPA guidance.

7.  See also our December 1993 NO_X Substitution Guidance at www.epa.gov/​ttn/​caaa/​t1/​memoranda/​noxsubst.pdf and www.epa.gov/​ttn/​oarpg/​t1/​memoranda/​clarisub.pdf.

8.  To cross-reference the calculations in these two tables, please see Tables 3, 4 and 5 in the TSD for this proposal.

9.  Our EI guidance documents are posted at https://www.epa.gov/​air-emissions-inventories/​emissions-inventory-guidance-documents.

10.  See also Tables 8 and 9 in the TSD for this proposal.

11.  See Tables 6 and 7 in the TSD for this proposal.

12.  See 80 FR 12264, 12285.

13.  The TCEQ established long ago that DFW area ozone levels are sensitive to NO_X emissions and we are aware of the transition in the urban core. See Appendix D (the conceptual model) for the State's Attainment Demonstration for the DFW area under the 2008 ozone standard, which is posted on the TCEQ Web site at https://www.tceq.texas.gov/​airquality/​sip/​dfw/​dfw-latest-ozone.