1 

# Technical Support Document

Dallas-Fort Worth Redesignation Substitute 1-hour and 1997 8-hour Ozone NAAQS

Background

Evaluation: 1-ho ur ozone NAAQS
1997 8-hour ozone NAAQS

Conclusion



# April 2016

FOR FURTHER INFORMATION CONTACT: Tr acie Donaldson, United States Environmental Protection Agency Region 6, Air Quality Section (6PD-Q). 1445 Ross Avenue, Dallas, TX 75202-2733, 214-665-66332 

### Background
The EPA is proposing to approve a demonstration provided by Texas that the Dallas-Fort Worth ozone nonattainment area (DFW area) has attain ed the revoked 1-hour ozone National Ambient Air Quality Standards (NAAQS) and the 1997 8-hour ozone NAAQS due to permanent and enforceable emission reductions, and that it will maintain thos e NAAQS for ten years from the date of the EPA’s approval of this demonstrat ion. The demonstration wa s provided to EPA in a report titled “Redesignation Subs titute Report for the Dallas-Fort Worth (DFW) One-Hour and 1997 Eight-Hour Ozone Standard Nonattainment Areas” (redesignation substitute report) submitted to EPA on August 18, 2015.

The determination that the area has attained both the 1-hour ozone and the 1997 8-hour ozone NAAQS is based upon three years of complete, qua lity-assured and state-certified ambient air monitoring data that show the area has monitore d attainment of the 1-hour ozone NAAQS for the 2004–2006 monitoring period and the 1997 8-hour ozone NAAQS for the 2012-14 monitoring period. Available data for 2015 show that the area continues to attain both standards (http://www.tceq.state.tx.us/cgi-bin/com pliance/monops/ozone_exceedance.pl). The determination that the area attained the 1-hour ozone NAAQS and the 1997 8-hour ozone NAAQS due to permanent and enforceable emissi on reductions, and that it will maintain those NAAQS for ten years from the date of the EPA’s approval of this demonstration is based on the EPA review of the demonstration provided by Texas and the evaluation of ozone monitoring data.
In 1979, the EPA promulgated the revised 1-hour ozone standard of 0.12 parts per million (ppm) (44 FR 8202, February 8, 1979). For ease of communication, many reports of ozone concentrations are given in parts per bill ion (ppb); ppb = ppm × 1000. Thus, 0.12 ppm becomes 120 ppb or 124 ppb when rounding is considered. An area exceeds the 1-hour ozone standard each time an ambient air quality monitor reco rds a 1-hour average ozone concentration above 0.12 ppm in any given day. Only the highest 1-ho ur ozone concentration at the monitor during any 24-hour day is considered when determining the number of exceedance days at the monitor. An area violates the 1-hour oz one standard if, over a consecutive 3-year period, more than 3 expected exceedances occur at the same monitor. For more information, please see ‘‘National 1- hour primary and secondary ambient air qual ity standards for ozone’’ (40 CFR 50.9) and ‘‘Interpretation of the 1-Hour Primary and Sec ondary National Ambient Air Quality Standards for ozone’’ (40 CFR Part 50, Appendix H).
The DFW four-county 1-hour ozone nonattainment area (Collin, Dallas, Denton, and Tarrant Counties) was designated in 1991 as moderate in accordance with the 1990 CAA Amendments (56 FR 56694). As a moderate nonattainment area , the four-county DFW area was required to demonstrate attainment of the 1-hour ozone standard by November 15, 1996. Ambient air monitoring data for the years 1994 through 1996, however, showed that the 1-hour ozone standard was exceeded more than one day per y ear over the three-year period. As a result, the EPA reclassified the four-county DFW area from a moderate to a serious nonattainment area (effective March 20, 1998) for failure to attain the 1-hour ozone standard by the November 1996 deadline (63 FR 8128). The EPA required the Stat e of Texas to submit a State Implementation3 

### Plan (SIP) revision within one year that dem onstrated attainment of the one-hour ozone NAAQS and addressed CAA requirements for serious ozone nonattainment areas.

On July 18, 1997, the EPA promulgated an 8- hour ozone NAAQS of 0.08 parts per million (ppm), known as the 1997 ozone standard. For ease of communication, many reports of ozone concentrations are given in parts per bill ion (ppb); ppb = ppm × 1000. Thus, 0.08 ppm becomes 80 ppb or 84 ppb when rounding is considered. See 62 FR 38856 and 40 CFR 50.10. Under the EPA regulations at 40 CFR part 50, Appendix I, th e 1997 ozone standard is attained when the 3- year average of the annual fourth highest daily maximum 8-hour average ambient ozone concentration is less than or equal to 0.08 ppm (up to 84 ppb).

On June 15, 2004, the EPA designated and classi fied the 9-county DFW (consisting of Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Ro ckwall and Tarrant counties) as a moderate nonattainment area under the 1997 8-hour ozone standa rd with an attainment date of no later than June 15, 2010 (see 69 FR 23858 and 69 FR 23951).

The fourth-highest daily ozone concentration over a 3-year period is called the design value (DV). The DV indicates the severity of the ozone pr oblem in an area; it is the ozone level around which a state designs its control strategy for attaining the ozone standard. A monitor’s DV is the fourth highest ambient concentra tion recorded at that monitor over the previous 3 years. An area’s DV is the highest of the design values from the area’s monitors.

The EPA revoked the 1-hour ozone standard on April 30, 2004 (69 FR 23951), and, on March 6, 2015, the EPA revoked the 1997 8-hour standard (80 FR 12264). As explained more fully in the March 6, 2015 rulemaking the EPA also adopte d a provision allowing states to seek a redesignation substitute for re voked standards. The regulations allow that if a redesignation substitute is approved the state may seek to ha ve “anti-backsliding” requirements for areas that were designated as nonattainment for the revoked standard shifte d to contingency measures if such action is consistent with sections 110( l) and 193 of the CAA (40 CFR 51.1105(b)(2)). The regulations authorize EPA to a pprove a redesignation substitute upon a showing by the state that:

1. The area has attained that revoked NAAQS due to permanent and enforceable emission reductions 2. The area will maintain that revoked NAAQS for 10 years from the date of the EPA’s approval of the showing.
The first criterion for a redesignatio n substitute is the same as tw o redesignation criteria found in CAA section 107(d)(3)(E)(i) and ( iii). The second criterion for a redesignation substitute is similar to the criterion for a maintenance plan which provides for maintenance of the NAAQS for at least 10 years after redesignation (CAA sections 107(d)3(E)(iv) and 175A). EPA provided guidance on the approach to evaluating state compliance with these provisions in EPA’s September 4, 1992 memo “Procedures for Proc essing Requests to Redesignate Areas to Attainment” from John Calcagni. For this reason, EPA believes it is appropri ate to consider that guidance when evaluating state co mpliance with the redesignation substitute requirements. (1992 redesignations guidance, www.epa.gov/ttn/oarpg/t5/memor anda/redesignmem090492.pdf).4 

### On August 18, 2015, the Texas Commission on Envi ronmental Quality (TCEQ) provided the “Redesignation Substitute Report for the Dall as-Fort Worth (DFW) One-Hour and 1997 EightHour Ozone Standard Nonattainment Areas” for use by the EPA in evaluating the request for approval of a redesignation substitute for the 1- hour and 1997 8-hour ozone standard obligations for the area. In this submission, Texas also reque sted that the nonattainment new source review (NNSR) classification for the revoked 1- hour and the revoked 1997 ozone NAAQS would no longer apply to the area. This Technical Suppor t Document evaluates whether the Texas Report supports a determination by the EPA that redesignati on substitute criteria in the above referenced rules have been met for the DFW area and whether, if a redesignation substitute is approved, NNSR could cease to apply for purposes of the revoked 1-hour and the revoked 1997 ozone standard.

Evaluation
1-hour ozone NAAQS
(1) The area has attained the revoked 1-ho ur NAAQS due to permanent and enforceable emission reductions.
a.) Is the DFW area attaining the 1-hour ozone NAAQS?

Table 1 contains the 1-hour ozone data for th e DFW 1-hour ozone nonattainment area monitors that show that the ar ea is currently attaini ng the 1-hour ozone NAAQS, consistent with 40 CFR Part 50, Appendix H. This data is i llustrated graphical ly in Figure 1.
Table 1: Current 1-hour Ozone NAAQS Design Values for the DFW Area

Years 1-Hour Ozone Design Value 2004-2006 124 ppb 2005-2007 124 ppb 2006-2008 118 ppb 2007-2009 115 ppb 2008-2010 110 ppb 2009-2011 110 ppb 2010-2012 108 ppb 2011-2013 108 ppb 2012-2014 102 ppb Preliminary 2013-2015 102 ppb5 Figure 1: One-Hour Ozone Desi gn Values for the DFW Area



### For the 1-hour ozone NAAQS, the design value wa s used to determine the classification of a nonattainment area but was not used for designa ting an area as attainment or otherwise. Designation is based on the maximu m number of expected exceedan ces over all the monitors in

an area 1 

### . To show that the DFW area no longer viol ates the 1-hour ozone NAAQS, the remainder of this section will be based on expected exceedances, calculated as per 40 CFR Part 50, Appendix H.
The expected number of exceedances of record in a metropolitan area is the maximum expected number of exceedances of all the area’s regulatory monitors’ individual expected number of exceedances. Because ozone concentrations vary spat ially, it is also prudent to investigate trends

1 The expected exceedances for a monitor is defined as the number of exceed ances that occurred in the calendar year plus an increment that accounts for missing data, averaged across three consecutive year s (for example, expected exceedances for 2013 is averaged across 2011, 20 12, and 2013). The in crement is calculated by finding the number of days without an associated ozone measurement that may not be assumed to be less than the standard, multiplied by the number of observed exceedances, then divided by the number of observations. This is done for each year and then averaged across three years to get the expected exceedances for that indi vidual monitor. Note that unlike the calculation for expected exceedances, design valu es are not adjusted for data completeness.6 

### at all regulatory monitors in an area. Ta ble 2: One-Hour Ozone Expected Exceedances by Monitor contains one-hour ozone expected number of exceedances at all regulatory monitors in the DFW four-county ozone nonattainment ar ea from 2006 through 2014. In 2006, all monitors in the DFW four-county ozone nonattainment area had expected exceedances less than the threshold of 1.0 per year. The number of days with ozone concentrations above 124 ppb occurring in the DFW area fell 100% from seven da ys in 1990 to zero days in 2014. In the last seven years, only one day had ozone concentr ations above the 124 ppb NAAQS threshold. This means that high ozone days are not only decreas ing in frequency but they are also decreasing geographically across th e entire region, showing an area wi de trend for the one-hour ozone NAAQS.
Table 2. One-Hour Ozone Expected Exceedances by Monitor for the DFW Area

The air quality data provided by Texas is consiste nt with that found in th e quality assured data found in the EPA Air Quality System (AQS), ther efore, EPA proposes to find that the DFW area is meeting the 1-hour ozone standard.
b.) Are the air quality improvements in the DFW area due to perm anent and enforceable emissions reductions?
Because Texas reasonably attributed the improveme nt in air quality to emission reductions which are permanent and enforceable, the EPA proposes to find that Texas has demonstrated that the observed ozone air quality improvement in the DFW area is due to permanent and enforceable reductions in emissions resulting from implem entation of the EPA approved SIP and Federal measures. The EPA approved SIP includes state and local measures can be found in 40 CFR 52.2270. 2006 2007 2008 2009 2010 2011 2012 2013 2014 2006

‐ 2008 2007

‐ 2009 2008

‐ 2010 2009

‐ 2011 2010

‐ 2012 2011

‐ 2013 2012

‐ 2014
Dallas Hinton (48

‐ 113

‐ 0069) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Denton Airport South (48

‐ 121

‐ 0034) 0.0 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0 Granbury (48

‐ 221

‐ 0001) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Corsicana Aiport (48

‐ 349

‐ 1051) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Fort Worth Northwest (48

‐ 439

‐ 1002) 0.0 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0
Frisco (48

‐ 085

‐ 0005) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Pilot Point (48

‐ 121

‐ 1032) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Greenville (48

‐ 231

‐ 1006) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Parker County (48

‐ 367

‐ 0081) 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0
Keller (48

‐ 439

‐ 2003) 0.0 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0
Dallas North #2 (48

‐ 113

‐ 0075) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Midlothian OFW (48

‐ 139

‐ 0016) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Cleburne Airport (48

‐ 251

‐ 0003) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Rockwall Heath (48

‐ 397

‐ 0001) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Grapevine Fairway (48

‐ 439

‐ 3009) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Dallas Redbird Airport Executive (48

‐ 113

‐ 0087) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Italy (48

‐ 139

‐ 1044) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Kaufman (48

‐ 257

‐ 0005) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Arlington (48

‐ 439

‐ 3011) 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.3 Eagle Mountain Lake (48

‐ 439

‐ 0075) 0.0 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0 3 year Expected Exceedances (avg.)

DFW Monitoring Site (Name and AQS #) Expected Exceedances by Year7 

### Texas presented data to show the long term decr ease in ozone concentrations in the DFW area and showing that this long term d ecrease in ozone levels can be attributed to a suite of nitrogen oxide (NO X 

### ) controls and volatile organic chemical ( VOC) controls with a particular emphasis on control of highly reactive VOCs.
In making this demonstration, the State presented several sets of data. Fi rst, the State provided emissions inventory data for 2002 through 2011. Secondly, the State provided an ambient concentration trend analysis for ozone precursors (NO X 

### and VOC) in the DFW area between 2002 and 2014. Finally, the State documented the VOC and NO X 

### emission control measures that have been implemented in the DFW area over the past 25 years.
A. Emissions Reductions as Shown by Emissions Inventory (EI) Data
The year 2012 was chosen as the base year because it is one of the three years used to determine the DV for the 2014 attainment year. 2011 emissions were compared to 2002 VOC and NO X 

### emissions when the DV was 110 ppb, to show that em ission reductions have occurred in the area, and have resulted in the ozone ai r quality improvement in the ar ea. 2006 was the first three-year period demonstrating attainment. By 2011, NO X 

### emissions have dropped by 36% and VOC emissions by 12% from 2002 levels.
These significant decreases resulted in the improv ement in ozone levels seen at the monitors. The emissions for both years were derived from periodic VOC and NO X 

### emission inventories, which are prepared every three years. Base d on the estimated emissions, the TCEQ has documented several emission trends to show that permanent and enforceable emission controls in various source sectors are responsible for significant downward trends in VOC and NO X 

### emission totals in the DFW area leading to atta inment. For a discussion of emission inventory preparation methods, see the discussion of th e preparation of the 2011 base year emission inventories below.

To demonstrate that VOC and NO X 

### emissions decreased between one of the violation years (2002) and the attainment year (2011), the TCEQ has documented DFW’s VOC and NO X 

### emissions for 2002 and 2011 for all anthropogenic s ource sectors. Table 3 lists these emissions for the 2002, 2005, 2008 and 2011 EI.

Table 3: DFW Four-County Nonattain ment Area Historical Emissions

Emissions Source Category 2002 2005 2008 2011
VOC Emissions (tpd)
Area 197.27 202.36 250.92 216.47
Non

‐ Road Mobile 70.11 59.57 62.11 47.54
On

‐ Road Mobile 118.39 102.95 91.73 76.71
Point 18.76 21.42 19.01 16.15
VOC Total 404.53 386.3 423.77 356.87
NO X Emissions (tpd)
Area 24.44 36.60 74.81 31.068 Non

‐ Road Mobile 104.08 110.58 115.19 93.26
On

‐ Road Mobile 345.10 313.70 225.53 191.55
Point 34.57 7.94 10.4 8.38
NO X Total 508.19 468.82 425.93 324.25



### Based on the 2002, 2005, 2008 and 2011 DFW area em issions information provided by the TCEQ, the EPA concludes that VOC and NO X 

### emission totals have significantly declined in the nonattainment area during the 2002–2011 period. These emission reductions have led to attainment of the 1-hour ozone standard in this area. The EPA concurs with Texas’ conclusions that the emission controls, emissions inventorie s, and emissions trends support the conclusion that attainment in the area is due to pe rmanent and enforceable emission reductions.
B. Impact of Emissions Controls Implementation: Trend Analysis
To assess the impact of emission control impl ementation, the TCEQ determined the VOC and NO X 

### ambient concentration trends in the DF W area from 2000 to 2014. Annual maxima, annual 90 th 

### percentile and annual aver age daily peak 1-hour NO X 

### values were analyzed. All three measures decreased markedly over the time period from 2000 to 2014, falling 32% (maximum), 60% (90 th 

### percentile) and 61.5% (average). St rong downward trends in ambient NO X 

### concentrations are evidence of the effectiveness of emission controls.
The other major class of ozone precursors is VOC. Since the mid-1990s, the TCEQ has collected 40-minute measurements, on an hourly basis, of over 40 species of VOC using auto-GC instruments. The TCEQ focused on two prevalen t compounds, ethylene and propylene, that are associated with rapid and efficient ozone form ation. Yearly geometric means were computed from valid ambient hourly measurements. The TCEQ calculated the geometric mean by taking the natural logarithm of each meas urement, averaging these logs, and then calculating the antilog of this mean log value. The geometric mean is a preferable statistic to median or arithmetic (ordinary) mean for evaluating the central tendency of data when the data are skewed, i.e., when the data are not symmetrically, or normally, distributed, but instead clustered around extreme high or low values. A geometric mean is more robust than an ordinary average, in that its value is not greatly influenced by one or a few very hi gh or very low values. Many distributions of pollutant measurements, especially VOC, in the DFW area are skewed.
Prior to 2010, only two of the nine monitors had enough valid data to calculate annual geometric mean ethylene. Values for ethylene are fairly low; the highest geometric mean ethylene in the DFW area in 2014 was below 0.6 parts per billi on carbon (ppbC). While trends are generally variable from year to year, the geometric mean ethylene has decreased at the two monitors with the longest record of auto-GC data. Ethylene at the Flower Mound Shiloh (C1007) monitor had been steadily increasing until 2013, when the geometric mean ethylene decreased in 2014. Concentrations at the Arlington UT Campus (C1018), Eagle Mountain Lake (C0075) and Kennedale Treepoint Drive (C1062) monitors saw increases between 2013 and 2014, although the Arlington UT Campus (C1018) and Kennedale Treepoint Driv e (C1062) monitors only have two years of valid data to cal culate the geometric mean.9 

### Like ethylene, prior to 2004 only three of the nine monitors had enough valid data to calculate annual geometric mean propylene. The geometric means for propyl ene are even lower than the geometric means for ethylene for most of the ye ars, with the highest geometric mean propylene concentration in the DFW area in 2014 below 0.4 ppbC. All monitors have been showing a steady decrease in geometric mean propylene from 2000 through 2014. The Fort Worth Northwest (C0013) monitor saw a slight increas e in propylene measurements between 2013 and 2014. Though decreasing at different rates, these long-term decreases in ambient concentrations of ethylene and propylene suggest overall indus trial and automobile emissions of these compounds have decreased considerably since 2000.
C. Permanent and Enforceable Emissions Controls Implemented
A broad range of control measures have been im plemented for each emission source category. In section 3.2 of the Redesignation Substitute Report, Texas identified the permanent and enforceable measures that led to attainment of the 1-hour ozone NAAQS. Table 4 below from the report lists existing ozone c ontrol strategies that have emi ssions reductions for both the 1- hour and the 1997 8-hour ozone standards. These measures are permanent and enforceable and are included in the EPA approved SIP (40 CFR 52.2270).

Table 4. Existing Ozone Control Measures Appl icable to the DFW 1- hour ozone Four-County and 1997 8-hour ozone Nine-County Nonattainment Areas (from section 3.2 of the Texas Report)

Measure Description Start Date(s) DFW Industrial, Commercial, and Institutional (ICI) Major Source Rule

30 Texas Administrative Code (TAC) Chapter 117, Subchapter B, Division 4 Applies to major sources (50 tons per year (tpy) of nitrogen oxides (NOx) or mo re) with affected units in Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties

Applies to major sources (100 tpy of NOx or more) with affected units in Wise County

Affected source categories included in rule: boilers; process heaters; stationary gas turbines, and duct burners used in turbine exhaust ducts; lime kilns; heat treat and reheat metallurgical furnaces; stationary internal combustion engines; incinerators; glass, fiberglass, and mineral wool melting furnaces; fiberglass and mineral wool curing ovens; natural gas-fired ovens and heaters; brick and ceramic kilns; lead smelting reverberatory and blast furnaces; natural gas-fired dryers used in organic solvent, printing ink, clay, brick, ceramictile, calcining, and vitrifying processes; and woodfired boilers March 1, 2009 or March 1, 2010, depending on source category

Note: these NO x control requirements are in addition to the NO x control strategies previously implemented for ICI major sources in Collin, Dallas, Denton, and Tarrant Counties in March 2002 for the one-hour ozone National Ambient Air Quality Standards (NAAQS)

January 1, 2017 for Wise County and wood-fired boilers in all ten counties of the DFW area

DFW ICI Minor Source Rule

30 TAC Chapter 117, Subchapter D, Division 2 Applies to all minor sources (less than 50 tpy of NOx) with stationary internal combustion engines in Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties March 1, 2009 for rich-burn gas-fired engines, diesel-fired engines, and dual-fuel engines March 1, 2010 for lean-burn gas-fired engines10 Measure Description Start Date(s) Stationary Diesel Engines 30 TAC Chapter 117, Subchapter B, Division 4 and Subchapter D, Division 2 and Subchapter C, Division 4 Prohibition on operating stationary diesel and dualfuel engines for testing and maintenance purposes between 6:00 a.m. and noon in Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties April 1, 2009

DFW Major Utility Electric Generation Source Rule

30 TAC Chapter 117, Subchapter C, Division 4 NO x control requirements for major source (50 tpy of NO x or more) utility electric generating facilities in Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties

NO x control requirements for major source (100 tpy of NO x or more) utility electric generating facilities in Wise County

Applies to utility boilers, auxiliary steam boilers, stationary gas turbines, and duct burners used in turbine exhaust ducts used in electric power generating systems

Note: these NO x control requirements are in addition to the NO x control strategies implemented for utilities in Collin, Dallas, Denton, and Tarrant Counties in 2001 through 2005 for the one-hour ozone NAAQS March 1, 2009 for Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties

January 1, 2017 for Wise County

Utility Electric Generation in East and Central Texas 30 TAC Chapter 117, Subchapter E, Division 1 NO x control requirements on utility boilers and stationary gas turbines (including duct burners used in turbine exhaust ducts) at utility electric generation sites in East and Central Texas, including Parker County May 1, 2003 through May 1, 2005

DFW Cement Kiln Rule 30 TAC Chapter 117, Subchapter E, Division 2 NO x control requirements for all Portland cement kilns located in Ellis County March 1, 2009

NO x Emission Standards for Nitric Acid Manufacturing – General 30 TAC Chapter 117, Subchapter F, Division 3 NO x emission standards for nitric acid manufacturing facilities (state-wide rule – no nitric acid facilities in DFW) November 15, 1999

East Texas Combustion Sources

30 TAC Chapter 117, Subchapter E, Division 4 NO x control requirements for stationary rich-burn, gas-fired internal combustion engines (240 horsepower and greater) Measure implemented to reduce ozone in DFW area although controls not applicable in DFW area March 1, 2010

Natural Gas-Fired Small Boilers, Process Heaters, and Water Heaters 30 TAC Chapter 117, Subchapter E, Division 3 NO x emission limits on small-scale residential and industrial boilers, process heaters, and water heaters equal to or less than 2.0 million British thermal units per hour May 11, 2000

Offset Lithographic Printing

30 TAC, Chapter 115, Subchapter E, Division 4 Control technology requirements for offset lithographic printing Revision to limit Volatile Organic Compounds (VOC) content of solvents used by offset December 31, 2000 for Collin, Dallas, Denton, and Tarrant Counties and March 1, 2009 in Ellis, Johnson,11 Measure Description Start Date(s) lithographic printing facilities and to include smaller sources in rule applicability Kaufman, Parker, and Rockwall Counties

March 1, 2011 for major printing sources (50 tons of VOC per year or more) and March 1, 2012 for minor printing sources (less than 50 tons of VOC per year) VOC Rules – Degassing Operations 30 TAC, Chapter 115, Subchapter F, Division 3 VOC control requirements for degassing during, or in preparation of, cleaning any storage tanks and transport vessels May 21, 2011 for Collin, Dallas, Denton, and Tarrant Counties

VOC Control Measures – Storage Tanks

30 TAC Chapter 115, Subchapter B, Division 1 Applies to major source storage tanks (50 tpy of VOC or more) in Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties

Applies to major source storage tanks (100 tpy of VOC or more) in Wise County

Requires controls for slotted guidepoles and more stringent controls for other fittings on floating roof tanks, and control requirements or operational limitations on landing floating roof tanks Eliminates exemption for st orage tanks for crude oil or natural gas condensate and regulates flash emissions from these tanks

New inspection requirements to control flashed gases from storage tanks and corresponding recordkeeping requirements for fixed roof storage tanks March 1, 2013

January 1, 2017 for major source storage tanks in Wise County and for new inspection requirements to control flashed gases from storage tanks and corresponding recordkeeping requirements for fixed roof storage tanks in Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant and Wise Counties

VOC Control Measures – Solvent-Using Processes

30 TAC Chapter 115, Subchapter E Revised rules to implement RACT requirements per Control Techniques Guidelines issued by the United States Environmental Pr otection Agency (EPA) including new control, testing, monitoring and recordkeeping requiremen ts for eight emission source categories in the DFW area: paper, film, and foil coatings; large appliance coatings; metal furniture coatings; miscellaneous metal and plastic parts coatings; automobile and light-duty truck coating; industrial cleaning solvents; miscellaneous industrial adhesives; and flexible package printing(see DFW AD SIP Revision for the 1997 EightHour Ozone Standard Nonattainment Area (2010- 022-SIP-NR)) March 1, 2013 for Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties

January 1, 2017 for Wise County

Refueling – Stage I

30 TAC, Chapter 115, Subchapter C, Division 2 Captures gasoline vapors that are released when gasoline is delivered to a storage tank Vapors returned to tank truck as storage tank is filled with fuel, rather than released into ambient air 1990 for Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties

January 1, 2017 for Wise County12 Measure Description Start Date(s) A SIP revision related to Stage I regulations was approved by the EPA, effective June 29, 2015 Refueling – Stage II

30 TAC, Chapter 115, Subchapter C, Division 4 Captures gasoline vapors when vehicle is fueled at
pump
Vapors returned through pump hose to petroleum storage tank, rather than released into ambient air 1992 (Collin, Dallas, Denton, and Tarrant Counties)

A SIP revision authorizing the decommissioning of Stage II vapor control equipment was approved by the EPA on March 17, 2014. Facilities may continue operating Stage II until August 31, 2018 VOC Control Measures

30 TAC Chapter 115 Control technology requirements for VOC sources for reasonably available control technology (RACT) and other SIP planning purposes including: storage, general vent gas, industri al wastewater, loading and unloading operations, general VOC leak detection and repair, solvent using processes, etc. December 31, 2002 and earlier for Collin, Dallas, Denton, and Tarrant Counties

June 15, 2007 or March 1, 2009 for Ellis, Johnson, Kaufman, Parker, and Rockwall Counties

January 1, 2017 for Wise County Texas Emissions Reduction Plan (TERP 30 TAC Chapter 114, Subchapter K Provides grant funds for on-road and non-road heavy-duty diesel engine replacement/retrofit. The first emissions reduction incentive grant projects funded under TERP were for fiscal years 2002 - 2003 (September 1, 2001, through August 31, 2003). To focus the emissions reduction benefits for the areas that needed them the most, applicationswere accepted only for projects in the HoustonGalveston-Brazoria (HGB) and DFW nonattainment areas for fi scal years 2002 through 2003. An application period limited to the DFW, HGB, and Beaumont-Port Arthur areas was done in 2006 and 2007. The allocation approach established by the commission for TERP included several grant programs for reducing emissions from mobile sources and encouraging the use of cleaner alternative fuels for transportation, including the Diesel Emissions Reduction Incentive Program providing grants to repl ace or upgrade heavy-duty on-road vehicles, non-road equipment, locomotives, marine vessels, and some stationary engines. January 2002

Texas Low Emission Diesel

30 TAC Chapter 114, Subchapter H, Division 2 Requires all diesel fuel for both on-road and nonroad use to have a lower aromatic content and a higher cetane number Phased in from October 31, 2005 through January 31, 2006

Texas Low Reid Vapor Pressure (RVP) Gasoline Requires all gasoline for both on-road and non-road use to have RVP of 7.8 pounds per square inch or less from May 1 through October 1 each year April 2000 in Ellis, Johnson, Kaufman, Parker, Rockwall, and Wise Counties13 Measure Description Start Date(s) 30 TAC Chapter 114, Subchapter H, Division 1 Vehicle Inspection/ Maintenance (I/M)

30 TAC Chapter 114, Subchapter C Yearly treadmill-type tes ting for pre-1996 vehicles and computer checks for 1996 and newer vehicles May 1, 2002 in Collin, Dallas, Denton, and Tarrant Counties

May 1, 2003 in Ellis, Johnson, Kaufman, Parker, and Rockwall Counties

The DFW area meets the FCAA, §182(b)(4) requirements to implement an Inspection and Maintenance (I/M) program , and according to 40 CFR §51.350(b)(2), an I/M program is required to cover the entire urbanized area based on the 1990 census. The current I/M program in the DFW ozone nonattainment area sufficiently covers a population equal to the DFW urbanized area, thus expansion of the I/M program to include Wise County is not required. California Gasoline Engines California standards for non-road gasoline engines 25 horsepower and larger May 1, 2004

Transportation Control Measures Various measures in North Central Texas Council of Governments’ (NCTCOG) long-range transportation plans 2007

Voluntary Energy Efficiency/Renewable Energy (EE/RE) See Chapter 3.3.3: En ergy Efficiency and Renewable Energy Measures See Chapter 3.3.3

Voluntary Mobile Emissions Reduction Program Various pedestrian, bicycle, traffic, and mass transit voluntary measures administered by NCTCOG 2007

Federal On-Road Measures Series of emissions limits implemented by the EPA for on-road vehicles

Included in measures: Tier 1, Tier 2, and Tier 3 light-duty and medium-duty passenger vehicle standards, heavy-duty vehicle standards, low sulfur diesel standards, National Low Emission Vehicle standards, and reformulated gasoline Phase in through 2010

Tier 3 phase in from 2017 through 2025

Federal Area/Non-Road Measures Series of emissions limits implemented by the EPA for area and non-road sources

Examples: diesel and gaso line engine standards for locomotives and leaf-blowers Phase in through 201814 

### In sum, the table above shows the breadth of cont rols that have been adopted and implemented in the DFW area. These controls have been im plemented over a period of decades. Texas has focused on the significant reductions that ha ve happened since 2002, demonstrating both NO X 

### and VOCs have declined signifi cantly. During this same time pe riod ozone levels have also declined. Table 3 shows th at both Federal Measures to cont rol on-road and off-road emissions and State instituted controls such as low emissi on diesel for marine vessels, additional storage tank controls and storage tank degassing controls have all contributed to these additional reductions. The EPA concludes that the reductions in ozone ar e due to these permanent and enforceable measures.
(2) The area will maintain the revoked NAAQ S for 10 years from the date of the EPA’s approval of the showing.

Consistent with the 1992 redesi gnations guidance, Texas provid ed an attainment emissions inventory and projected future emissions invent ories for the four-county nonattainment area. To demonstrate maintenance of the 1-hour ozone standard, the TCEQ projected VOC and NO X 

### emissions to 2028 and to several inte rim years, 2014, 2017, 2020, 2023, 2026 and 2028. These emissions were compared to the 2012 base ye ar emissions to show that emissions of NO X 

### and VOC, remain below the attainment levels for the entire demonstrated maintenance period.
In the August 18, 2015 ozone redesignation substitu te request, the TCEQ compared the VOC and NO X 

### emissions for 2014, 2017, 2020, 2023, 2026 and 2028 for all major source sectors, and in total for the DFW four-county nonattainment area. In its ozone maintenance demonstration, the TCEQ presented the NO X 

### and VOC emission totals for the 2012 base year and all projection years for the DFW area. The TCEQ’s mainte nance demonstration shows that in 2014, 2017, 2020, 2023, 2026 and 2028, VOC and NO X 

### emission totals for the DFW area are projected to be below the 2012 VOC and NO X 

### emissions for the area.

NO X 

### emissions in the DFW four-county nonattai nment area are projec ted to decline by 51 percent between 2012 and 2028. VOC emissions in the DFW Four-County nonattainment area are projected to decline by approximate ly 17.5 percent between 2012 and 2028. Based on photochemical modeling analyses showing that the formation of ozone in the DFW area is more sensitive to NO X 

### than to VOC emissions, the small decrease in VOC emissions is expected to be much less significant than the decrease in NO X



### . Based on this analysis, emissions in the DFW four-county nonattainment area are expected to remain at levels consistent with attainment for the 1-hour ozone standard through 2028.
The 2012 base year and the 2014, 2017, 2020, 2023, 2026 and 2028 future year EI summaries by source categories for the DFW area are shown in Table 5: DFW Four-County Nonattainment Area NO X 

### Emissions by Source Category (tons per day) and Table 6: DFW Four-County Nonattainment Area VOC Emissions by Source Category (tons per day) . Contributions from biogenic emissions are not included in the su mmary because this analysis is limited to anthropogenic sources.15 

### Table 5: DFW Four-County nonattainment area NO X 

### Emissions by Source Category (tpd)
Category 2012 2014 2017 2020 2023 2026 2028

Point Sources 8.47 8.79 29.47 29.57 29.65 29.71 29.76

Area Sources 28.54 29.41 27.79 25.96 24.9 24.68 24.68

On

‐ Road Mobile Sources (MOVES 2014) 171.2 147.42 96.74 69.67 54.44 43.33 38.83

Non

‐ Road Mobile Sources 76.95 72.29 61.56 53.31 48.87 46.36 45.66

Total 285.16 257.91 215.56 178.51 157.86 144.08 138.93



### Table 6: DFW Four-County nonattainment ar ea VOC Emissions by Source Category (tpd)
Category 2012 2014 2017 2020 2023 2026 2028

Point Sources 11.11 11.02 11.52 11.71 11.86 11.99 12.08

Area Sources 218.9 224.51 218.56 211.43 209.81 210.69 211.77

On

‐ Road Mobile Sources (MOVES 2014) 78.56 71.20 55.59 46.81 41.53 35.85 32.94

Non

‐ Road Mobile Sources 41.39 36.48 32.59 31.08 31.04 31.52 32.08

Total 349.96 343.21 318.26 301.03 294.24 290.05 288.87



### Trend analysis using the 2028 future year emi ssions shows an overall decrease of 207.32 tpd in combined NO X 

### and VOC emissions for the DFW area. This net change includes a projected 61.09 tpd decrease in VOC and a 146.23 tpd decrease in NO X 

### from 2012 levels.
In general, growth in point and area source emissi ons are projected to be offset by the continued introduction of cleaner on road and off road vehicles.
The EPA proposes to conclude that the TCEQ has demonstrated maintenance of the ozone standard during the 10-plus year maintenance period for the DFW area through projections of VOC and NO X 

### emissions that show that the emissions will remain below the 2012 base year levels during the maintenance period.16 

### 1997 8-hour ozone NAAQS
(1) The area has attained the revoked NAAQS due to permanent and enforceable emission reductions.
a.) Is the DFW area attaining the 1997 8-hour ozone NAAQS?

Table 7 contains the 8-hour ozone data for the DFW 1997 8-hour ozone nine-county nonattainment area monitors that show that the area is currently attain ing the 1997 8-hour ozone NAAQS, consistent with 40 CFR Part 50, Appendix H. This data is summarized in Table 8 and illustrated graphically in Figure 2.
Table 7: The DFW Nine-County Nonattainment Area Fourth High 8-hour Ozone Average Concentrations and Design Values (ppm) for 2012-2014

Site Name 4 th 

### Highest Daily Max Design Value (2012-2014) 2012 2013 2014

Frisco C31 83 84 78 82 Dallas Hinton St. C401/C60/C 82 84 78 81

Dallas North No. 2 C63 81 83 77 80 Dallas Redbird Airport C402 81 80 73 78 Denton Airport South C56 83 87 81 84 Pilot Point 82 84 79 82 Midlothian OFW C52/C137 76 77 71 75 Italy C1044 69 72 67 69 Cleburne Airport C77 79 79 76 78 Kaufman C71 70 74 70 71 Parker County C76 78 79 74 77 Rockwall Heath C69 77 77 73 76 Eagle Mountain Lake C75 82 81 79 81 Ft. Worth Northwest C13 80 81 80 80 Keller C17 87 85 77 83 Grapevine Fairway C70 86 86 80 84 Arlington Municipal Airport 83 80 75 79

Table 8: Current 1997 8-hour Ozone NAAQS De sign Values for the DFW Nine-County Nonattainment Area

Years 8-Hour Ozone Design Value
2011-2013 87 ppb
2012-2014 84 ppb
Preliminary 2013-2015 83 ppb17 

### Figure 2: 8-Hour Ozone Design Values for the DFW Nine-County Nonattainment Area

The air quality data provided by Texas is consiste nt with that found in th e quality assured data found in the EPA Air Quality System (AQS), ther efore, EPA proposes to find that the DFW area is meeting the 1997 8-hour ozone standard.
b.) Are the air quality improvements in the DFW area due to perm anent and enforceable emissions reductions?
Because Texas reasonably attributed the improveme nt in air quality to emission reductions which are permanent and enforceable, the EPA proposes to find that Texas has demonstrated that the observed ozone air quality improvement in the DFW area is due to permanent and enforceable reductions in emissions resulting from implem entation of the EPA approved SIP and Federal measures. The EPA approved SIP includes state a nd local measures and can be found in 40 CFR 52.2270.
Texas presented data to show the long term d ecrease in ozone concentrations in the DFW area and showing that this long term decrease in ozone levels can be attributed to a suite of nitrogen oxide (NO X 

### ) controls and volatile organic compound (VOC ) controls with a particular emphasis on control of highly reactive VOCs.18 

### In making this demonstration, the State presented several sets of data. Fi rst, the State provided emissions inventory data for 2002 through 2011. Secondly, the State provided an ambient concentration trend analysis for ozone precursors (NO X 

### and VOC) in the DFW nine-county nonattainment area between 2002 and the period in which the standard was attained, 2012-2014. Finally, the State documented the VOC and NO X 

### emission control measures that have been implemented in the DFW area over the past 25 years.
A. Emissions Reductions as Shown by Emissions Inventory (EI) Data
The attainment EI base year is 2012 because it is one of the three years used to determine the design value (DV) for the 2014 attainment year . 2012 emissions were compared to 2002 VOC and NO X 

### emissions when the DV was 99 ppb, to show th at emission reductions have occurred in the area, and have resulted in the ozone air qu ality improvement in the area. 2014 is the first three-year period demonstrating attainment. By 2011 (the most re cent year for EI data), NO X 

### emissions were estimated to have droppe d by 30% and VOC emissions by 46% from 2002 levels.
These significant decreases resulted in the improv ement in ozone levels seen at the monitors. The emissions for both years were derived from periodic VOC and NO X 

### emission inventories, which are prepared every three years. Base d on the estimated emissions, the TCEQ has documented several emission trends to show that permanent and enforceable emission controls in various source sectors are responsible for significant downward trends in VOC and NO X 

### emission totals in the DFW area leading to atta inment. For a discussion of emission inventory preparation methods, see the discussion of th e preparation of the 2012 base year emission inventories below.

To demonstrate that VOC and NO X 

### emissions decreased between one of the violation years (2002) and the attainment year (2014), the TCEQ has documented DFW’s VOC and NO X 

### emissions for 2002 and 2011 for all anthropogenic s ource sectors. Table 9 lists these emissions for the 2002, 2005, 2008 and 2011 EI.19 

### Table 9: DFW 9-County Nonattainme nt Area Historical Emissions

Emissions Source Category 2002 2005 2008 2011
VOC Emissions (tons per day or tpd)

Area 197.27 202.36 250.92 216.47

Non-Road Mobile 70.11 59.57 62.11 47.54

On-Road Mobile 118.39 102.95 91.73 76.71

Point 18.76 21.42 19.01 16.15

VOC Total 404.53 386.30 391.32 356.87

NO X 

### Emissions (tpd)

Area 23.69 47.52 147.25 31.34

Non-Road Mobile 118.97 130.03 270.60 230.09

On-Road Mobile 428.49 385.57 141.87 112.40

Point 79.23 56.93 49.12 37.69

NO X 

### Total 650.38 620.05 608.84 411.52

Based on the 2002, 2005, 2008 and 2011 DFW 9-county 1997 8-hour ozone nonattainment area emissions information provided by the TC EQ, the EPA concludes that VOC and NO X 

### emission totals have significantly declined in the nine-county nonattainmen t area during the 2002–2011 period. These emission reductions have led to atta inment of the 1997 8-hour ozone standard in this area. The EPA concurs with Texas’ conc lusions that the emission controls, emissions inventories, and emissions trends support the conclusion that attainment in the area is due to permanent and enforceable emission reductions.
B. Impact of Emissions Controls Implementation: Trend Analysis
To assess the impact of emission control impl ementation, the TCEQ determined the VOC and NO X 

### ambient concentration trends in the DF W area from 2000 to 2014. Annual maxima, annual 90 th 

### percentile and annual average daily peak NO X 

### values were analyzed. All three measures decreased markedly over the time period from 2000 to 2014, falling 32% (maximum), 60% (90 th 

### percentile) and 61.5% (average). St rong downward trends in ambient NO X 

### concentrations are evidence of the effectiven ess of emission controls.
The other major class of ozone precursors is VOC. Since the mid-1990s, the TCEQ has collected 40-minute measurements, on an hourly basis, of over 40 species of VOC using auto-GC instruments. The TCEQ focused on two prevalen t compounds, ethylene and propylene, that are20 

### associated with rapid and efficient ozone form ation. Yearly geometric means were computed from valid ambient hourly measurements. A geom etric mean was calculated by taking the natural logarithm of each measurement, averaging these l ogs, and then calculating the antilog of this mean log value. The geometric mean is a preferable statistic to median or arithmetic (ordinary) mean for evaluating the central tendency of data wh en the data are skewed, that is, when the data are not symmetrically, or normall y, distributed, but instead cluste red around extreme high or low values. It is more robust than an ordinary averag e, meaning its value is not greatly influenced by one or a few very high or very low values. Ma ny distributions of pollutant measurements, especially VOC, in the DFW area are skewed, thus the geometric mean was evaluated to provide an assessment of VOC emissions in the DFW area.
Prior to 2010, only two of the nine monitors had enough valid data to calculate annual geometric mean ethylene. Values for ethylene are fairly low; the highest geometric mean ethylene in the DFW area in 2014 was below 0.6 parts per billi on carbon (ppbC). While trends are generally variable from year to year, the geometric mean ethylene has decreased at the two monitors with the longest record of auto-GC data. Ethylene at the Flower Mound Shiloh (C1007) monitor had been steadily increasing until 2013, when the geometric mean ethylene decreased in 2014. Concentrations at the Arlington UT Campus (C1018), Eagle Mountain Lake (C0075) and Kennedale Treepoint Drive (C1062) monitors saw increases between 2013 and 2014, although the Arlington UT Campus (C1018) and Kennedale Treepoint Driv e (C1062) monitors only have two years of valid data to cal culate the geometric mean.
Like ethylene, prior to 2004 only three of the nine monitors had enough valid data to calculate annual geometric mean propylene. The geometric means for propyl ene are even lower than the geometric means for ethylene for most of the ye ars, with the highest geometric mean propylene concentration in the DFW area in 2014 below 0.4 ppbC. All monitors have been showing a steady decrease in geometric mean propylene from 2000 through 2014. The Fort Worth Northwest (C0013) monitor saw a slight increas e in propylene measurements between 2013 and 2014. Though decreasing at different rates, these long-term decreases in ambient concentrations of ethylene and propylene suggest overall indus trial and automobile emissions of these compounds have decreased considerably since 2000.
C. Permanent and Enforceable Emissions Controls Implemented
A broad range of control measures have been im plemented for each emission source category. In section 3.2 of the redesignation substitute report, Texas identified the permanent and enforceable measures that led to attainment of the 1997 8-hour ozone NAAQS. S ee the 1-hour evaluation part C. for Table 4 listing existing ozone control strategies that have em issions reductions for both the 1-hour and the 1997 8-hour ozone stan dards. These measures are permanent and enforceable and are included in th e EPA approved SIP (40 CFR 52.2270).
(2) The area will maintain the revoked NAAQ S for 10 years from the date of the EPA’s approval of the showing.

Consistent with the 1992 redesi gnations guidance, Texas provid ed an attainment emissions inventory and projected future emissions invent ories for the nine-county nonattainment area. To21 

### demonstrate maintenance of the 1997 8-hour ozon e standard, the TCEQ projected VOC and NO X 

### emissions to 2028 and to several inte rim years, 2014, 2017, 2020, 2023, 2026 and 2028. These emissions were compared to the 2012 base ye ar emissions to show that emissions of NO X 

### and VOC, remain below the attainment levels for the entire demonstrated maintenance period.
In the August 18, 2015 ozone redesignation substitu te request, the TCEQ compared the VOC and NO X 

### emissions for 2014, 2017, 2020, 2023, 2026 and 2028 for all major source sectors, and in total for the DFW nine-county nonattainment area. In its ozone maintenance demonstration, the TCEQ presented the NO X 

### and VOC emission totals for the 2012 base year and all projection years for the DFW area. The TCEQ’s mainte nance demonstration shows that in 2014, 2017, 2020, 2023, 2026 and 2028, VOC and NO X 

### emission totals for the DFW area are projected to be below the 2012 VOC and NO X 

### emissions for the area.

NO X 

### emissions in the DFW nine-county nonattai nment area are projec ted to decline by 46 percent between 2012 and 2028. VOC emissions in the DFW nine-county nonattainment area are projected to decline by approximately 19 percent between 2012 and 2028. Based on photochemical modeling analyses showing that the formation of ozone in the DFW area is more sensitive to NO X 

### than to VOC emissions, the small decrease in VOC emissions is expected to be much less significant than the decrease in NO X



### . Based on this analysis, emissions in the DFW nine-county nonattainment area are expected to remain at levels consistent with attainment for the 1997 8- hour ozone standard from 2014 through 2028.
The 2012 base year and the 2014, 2017, 2020, 2023, 2026 and 2028 future year EI summaries by source categories for the DFW area are shown in Table 10: DFW Nine-County Nonattainment Area NO X 

### Emissions by Source Category (tons per day) and Table 11: DFW Nine-County Nonattainment Area VOC Emissions by Source Category (tons per day) . Contributions from biogenic emissions are not included in the su mmary because this analysis is limited to anthropogenic sources.

Table 10: NO X 

### Emission Projections (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028
Point Sources 30.80 31.25 62.38 62.49 62.57 62.64 62.71

Area Sources 33.60 34.77 32.01 28.98 27.37 26.97 26.93

On-Road Mobile Sources 216.74 188.65 129.19 95.95 77.87 64.62 59.75

Non-Road Mobile Sources 92.98 86.83 72.83 62.10 56.21 52.71 51.55

Total 374.12 341.50 296.41 249.52 224.02 206.94 200.94

Table 11: VOC Emission Projections (tons per day)22 

### Category 2012 2014 2017 2020 2023 2026 2028
Point Sources 27.66 28.61 29.46 29.97 30.41 30.82 31.10

Area Sources 265.43 273.08 260.19 245.76 241.13 241.19 242.15

On-Road Mobile Sources 92.17 83.75 65.62 55.36 49.21 42.70 39.49

Non-Road Mobile Sources 46.87 41.34 36.73 34.78 34.55 35.00 35.53

Total 432.13 426.78 392.00 365.87 355.30 349.71 348.27

Trend analysis using the 2028 future year emi ssions shows an overall decrease of 257.04 tpd in combined NO X 

### and VOC emissions for the DFW area. This net change includes a projected 83.86 tpd decrease in VOC and a 173.18 tpd decrease in NO X 

### from 2012 levels.
In general, growth in point and area source emissi ons are projected to be offset by the continued introduction of cleaner on road and off road vehicles.
The EPA proposes to conclude that the TCEQ has demonstrated maintenance of the ozone standard during the 10-plus year maintenance period for the DFW area through projections of VOC and NO X 

### emissions that show that the emissions will remain below the 2012 base year levels during the maintenance period.
D. The Effects of a Redesignati on Substitute Final Action in DFW Texas has requested that EPA c oncur that “...the relevant nonattainment NSR provisions no longer apply to the areas.” See, Cover letter for the HGB and Dallas Redesignation Substitute Submittals. Generally, if we approve a redesignati on substitute, the state may request to revise its SIP to revise or remove provisions for NNSR for the revoke d standard, provided that such action is consistent with CAA sections 110(l) and 193. See, 40 CFR 51. 1105(b)(2). If the EPA finalizes a redesignation substitute for the DFW area, EPA believes that a SIP revision in this particular case is not necessary because the oz one standards in question have been revoked and because of a provision in the Texas SIP which ch anges the designation of the area to what is listed in 40 CFR part 81. We believe a plain reading of this provi sion in the Texas SIP establishes an area’s classification and thus the related major source thresholds and offset ratios for Texas as 40 CFR part 81 is updated withoutfurther action by Texas. Any other antibacksliding provisions that are in the Texas SIP may only be changed through the SIP revision process. EPA believes that the following language in the Texas SIP supports this analysis of an automatic updating of the ozone classification:

TAC Chapter 101 General Air Quality Rule s, Subchapter A: General Rules , §101.1. Definitions. (71) Nonattainment area--A defined region within the state that is designated by the United States Environmen tal Protection Agency (EPA) as failing to meet the national ambient air quality standa rd (NAAQS or standard) for a pollutant for which a standard exists. The EPA will desi gnate the area as nonattainment under the provisions of 42 United States Code, §7407(d). For the official list and boundaries of23 

### nonattainment areas, see 40 Code of Federa l Regulations (CFR) Part 81 and pertinent Federal Register notices. The designations and classifications fo r the one-hour ozone national ambient air quality standards in 40 CFR Part 81 were retained for the purpose of anti-backsliding and upon determination by th e EPA that any require ment is no longer required for purposes of anti-backsliding, then that requirem ent no longer applies.
NNSR Offset Ratios and Major So urce Thresholds are defined in TAC Chapter 116 Control of Air Pollution by Permits for New Construction or Modification, Subcha pter A: Definitions, §116.12. Nonattainment and Prevention of Significan t Deterioration Review Definitions (19) Major Stationary Source and (20) Major Modification. Both defin itions refer to Table 1 below.

TABLE I 2


### MAJOR SOURCE/MAJOR MODIFI CATION EMISSION THRESHOLDS POLLUTANT designation MAJOR SOURCE SIGNIFICANT LEVEL OFFSET RATIO Tons/year tons/year minimum

OZONE (VOC, NOX) I marginal 100 40 1.10 to 1 II moderate 100 40 1.15 to 1 III serious 50 25 1.20 to 1 IV severe 25 25 1.30 to 1

Further, DFW is still subject to Nonattain ment NSR for the 2008 and 2015 Ozone Standards.

It should also be noted that when a new classification is in place, that, in and of itself, does not relieve sources in the area of their obligations under previously established permit conditions.

Conclusion
The review of the Texas redesign ation substitute report found that Texas has demonstrated that:
(1) The DFW area has attained the revoked 1- hour ozone and the revoked 1997 8-hour ozone NAAQS due to permanent and enforceable emission reductions (2) The DFW area will maintain the revoked 1-hour ozone and the revoked 1997 8-hour NAAQS for ten years from the date of th e EPA’s approval of this demonstration.
EPA is proposing to approve the DFW redesigna tion substitute for th e revoked 1-hour and the revoked 1997 8-hour ozone NAAQS. Upon final appr oval of the redesigna tion substitute, the area’s NNSR classification will be determined by the next highest classification remaining for that area.

2 Only Ozone is included here