1

Technical Support Document 

Houston-Galveston-Brazoria Redesignation Substitute 

1997 8-Hour Ozone NAAQS 

Background 

Evaluation 

Conclusion 

April 2016 

FOR FURTHER INFORMATION CONTACT: Tracie Donaldson, United States 

Environmental Protection Agency Region 6, State Implementation Section B (6MM-AB). 

1445 Ross Avenue, Dallas, TX 75202-2733, 214-665-6633 
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Background 

The EPA is proposing to approve a demonstration provided by Texas that the HoustonGalveston-Brazoria 1997 8-hour ozone nonattainment area (HGB area) has attained the revoked 

1997 8-hour ozone National Ambient Air Quality Standards (NAAQS) due to permanent and 

enforceable emission reductions, and that it will maintain that NAAQS for ten years from the 

date of the EPA’s approval of this demonstration. The demonstration was provided to EPA in a 

report titled “Redesignation Substitute Report for the Houston-Galveston-Brazoria 1997 EightHour Ozone Standard Nonattainment Area” (Redesignation Substitute Report) submitted to EPA 

on August 18, 2015. 

The determination that the area has attained the 1997 8-hour ozone NAAQS is based upon three 

years of complete, quality-assured and state-certified ambient air monitoring data that show the 

area has monitored attainment of the 1997 8-hour ozone NAAQS for the 2012–2014 monitoring 

period. Available data for 2015 shows that the area continues to attain the 1997 8-hour standard 

(http://www.tceq.state.tx.us/cgi-bin/compliance/monops/ozone_exceedance.pl). The 

determination that the area attained the 1997 8-hour ozone NAAQS due to permanent and 

enforceable emission reductions, and that it will maintain that 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. 

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 billion (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, the 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 April 30, 2004, the EPA designated and classified the 8-county HGB area (consisting of 

Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery and Waller counties) as 

a Moderate nonattainment area under the 1997 ozone standard with an attainment date of no later 

than June 15, 2010 (see 69 FR 23858 and 69 FR 23951). On June 15, 2007, we received a 

request from the Governor of Texas seeking voluntary reclassification of the HGB area from a 

Moderate nonattainment area to a Severe nonattainment area under the 1997 ozone standard, 

which we approved on October 1, 2008 (73 FR 56983).1

 Subsequently, the State submitted the 

Reasonable Further Progress (RFP) and Attainment Demonstration (AD) SIPs for the HGB 

Severe area under the 1997 ozone standard. These RFP and AD SIPs were approved on January 

2, 2014 (see 79 FR 51 and 79 FR 57, respectively). 

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 problem 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 

                                                            

1

 The attainment date for the HGB Severe nonattainment area is as expeditiously as practicable, but not later than 

June 15, 2019. 
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fourth highest ambient concentration 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 adopted a provision allowing states to seek a 

redesignation substitute for revoked standards. The regulations allow that if a redesignation 

substitute is approved the state may seek to have “anti-backsliding” requirements for areas that 

were designated as nonattainment for the revoked standard shifted 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 approve 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 redesignation substitute is the same as two 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 Processing Requests to Redesignate Areas to 

Attainment” from John Calcagni. For this reason, EPA believes it is appropriate to consider that 

guidance when evaluating state compliance with the redesignation substitute requirements. (1992 

redesignations guidance, www.epa.gov/ttn/oarpg/t5/memoranda/redesignmem090492.pdf). 

On August 18, 2015, the Texas Commission on Environmental Quality (TCEQ) provided the 

“Redesignation Substitute Report for the Houston-Galveston-Brazoria 1997 Eight-Hour Standard 

Nonattainment Area” for use by the EPA in evaluating the request for approval of a 

redesignation substitute for the 1997 8-hour ozone standard obligations for the area. In this 

submission, Texas also requested that the nonattainment new source review (NNSR) 

classification for the revoked 1997 ozone NAAQS would no longer apply to the area. This 

Technical Support Document evaluates whether the Texas Report supports a determination by 

the EPA that redesignation substitute criteria in the above referenced rule has been met for the 

HGB area and whether, if a redesignation substitute is approved, NNSR could cease to apply for 

purposes of the revoked 1997 ozone standard.

Evaluation 

(1) The area has attained the revoked NAAQS due to permanent and enforceable emission 

reductions. 

a.) Is the HGB area attaining the 1997 8-hour ozone NAAQS? 

Table 1 contains the 8-hour ozone data for the HGB 1997 8-hour ozone nonattainment area 

monitors that show that the area is currently attaining the 1997 8-hour ozone NAAQS, consistent 
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with 40 CFR Part 50, Appendix H. This data is summarized in Table 2 and illustrated graphically 

in Figure 1. 

Table 1: The HGB Area Fourth High 8-hour Ozone Average Concentrations and Design 

Values (ppm) for 2012-20142

Site Name and AQS Number 4th Highest Daily Max Design Value 

2012 2013 2014 (2012-2014)

Seabrook Friendship Park 

482011050 

86 67 65 72 

Houston Westhollow 

482010066 81 77 70 76 

Houston Deer Park #2 

482011039 85 69 63 72 

Houston North Wayside 

482010046 75 70 62 69 

Houston Monroe 

482010062 85 74 65 74 

Conroe Relocated 

483390078 82 75 72 76 

Houston East 

482011034 83 69 66 72 

Channelview 

482010026 77 61 64 67 

Lake Jackson 

480391016 71 67 61 66 

Baytown Garth 

482011017 71 61 67 66 

Park Place 

482010416 77 79 66 74 

Houston Croquet 

482010051 79 79 67 75 

Houston Aldine 

482010024 75 74 68 72 

Houston Bayland Park 

482010055 77 81 67 75 

Clinton 

482011035 81 67 58 68 

Northwest Harris County 

482010029 82 80 63 75 

                                                            

2 These ozone monitors have remained in the same location for the duration of the monitoring period from 2012 to 

2014. The TCEQ website includes monitoring data for the Texas Avenue site, but Table 1 here does not. Data from 

the Texas Avenue site is excluded because the site does not meet siting criteria required by 40 CFR Part 58 

Appendix E. The TCEQ has requested NAAQS exclusion for the pollutants monitored at this site since 2002. The 

TCEQ ozone monitors and data are posted at https://www.tceq.texas.gov/cgibin/compliance/monops/8hr_attainment.pl. 
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Manvel Croix Park 

480391004 87 84 71 80 

Lang 

482010047 81 79 64 74 

Table 2: Current 1997 8-hour Ozone NAAQS Design Values for the HGB Area 

Years 8-Hour Ozone 

Design Value 

2011-2013 87 ppb 

2012-2014 80 ppb 

Preliminary 

2013-2015 

80 ppb 

Figure 1: 8-Hour Ozone Design Values for the HGB Area 

The air quality data provided by Texas is consistent with that found in the quality assured data 

found in the EPA Air Quality System (AQS), therefore, EPA proposes to find that the HGB area 

is meeting the 1997 8-hour ozone standard. 
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b.) Are the air quality improvements in the HGB area due to permanent and enforceable 

emissions reductions? 

Because Texas reasonably attributed the improvement 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 HGB area is due to permanent and enforceable 

reductions in emissions resulting from implementation of the EPA approved SIP and Federal 

measures. The EPA approved SIP includes state and local measures that can be found in 40 CFR 

52.2270. 

Texas presented data to show the long term decrease in ozone concentrations in the HGB area 

and showing that this long term decrease in ozone levels can be attributed to a suite of nitrogen 

oxide (NOx) 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. First, the State provided 

emissions inventory data for 2002 through 2011. Secondly, the State provided an ambient 

concentration trend analysis for ozone precursors (NOX and VOC) in the HGB area between 

2002 and the period in which the standard was attained, 2012-2014. Finally, the State 

documented the VOC and NOX emission control measures that have been implemented in the 

HGB 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 NOX emissions when the DV was 178 ppb, to show that emission reductions have occurred 

in the area, and have resulted in the ozone air quality improvement in the area. 2014 is the first 

three-year period demonstrating attainment. By 2011 (the most recent year for EI data), NOX

emissions were estimated to have dropped by 30% and VOC emissions by 46% from 2002 

levels. 

These significant decreases resulted in the improvement in ozone levels seen at the monitors. 

The emissions for both years were derived from periodic VOC and NOX emission inventories, 

which are prepared every three years. Based 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 NOX

emission totals in the HGB area leading to attainment. For a discussion of emission inventory 

preparation methods, see the discussion of the preparation of the 2012 base year emission 

inventories below. 

To demonstrate that VOC and NOX emissions decreased between one of the violation years 

(2002) and the attainment year (2014), the TCEQ has documented HGB’s VOC and NOX

emissions for 2002 and 2011 for all anthropogenic source sectors. Table 3 lists these emissions 

for the 2002, 2005, 2008 PEI and 2011 EI. 
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Table 3: HGB Eight-County Nonattainment Area Historical Emissions 

Emissions Source Category 2002 2005 2008 2011

VOC Emissions (tons per day or tpd) 

Area 422.14 425.83 449.6 308.74

Non-Road Mobile 82.79 72.28 62.65 49.92

On-Road Mobile 115.34 106.58 96.37 85.05

Point 149.37 140.08 108.1 96.11

VOC Total 769.64 744.77 716.72 539.82

NOX Emissions (tpd) 

Area 27.79 16.04 25.41 21.15

Non-Road Mobile 145.25 156.04 149.24 121.11

On-Road Mobile 322.67 260.98 190.58 213.57

Point 339.49 194.52 111.38 108.48

NOX Total 835.2 627.58 476.61 464.31

Based on the 2002, 2005, 2008 and 2011 HGB area emissions information provided by the 

TCEQ, the EPA concludes that VOC and NOX emission totals have significantly declined in the 

nonattainment area during the 2002–2011 period. These emission reductions have led to 

attainment of the 1997 8-hour ozone standard in this area. The EPA concurs with Texas’ 

conclusions 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 implementation, the TCEQ determined the VOC and 

NOX ambient concentration trends in the HGB area from 2000 to 2014. Annual maxima, annual 

90th percentile and annual average daily peak NOX values were analyzed. All three measures 

decreased markedly over the time period from 2000 to 2014, falling 40% (maximum), 29% (90th

percentile) and 27% (average). Strong downward trends in ambient NOX 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 prevalent compounds, ethylene and propylene, that are 

associated with rapid and efficient ozone formation. Since the majority of VOC production 

occurs along the Houston Ship Channel, the eight auto-GC instruments near the area were 

examined. Yearly geometric means were computed from valid ambient hourly measurements. 

The TCEQ calculated the geometric mean by taking the natural logarithm of each measurement, 

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 
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a few very high or very low values. Many distributions of pollutant measurements, especially 

VOC, in the HGB area are skewed. 

Prior to 2004, only three of the eight monitors had enough valid data to calculate annual 

geometric mean ethylene. Generally, the geometric mean ethylene concentrations at all of the 

auto-GC monitors have decreased. Ethylene at the Channelview monitor (C15) steadily 

decreased until an increase in 2013 and then decreased again in 2014. Concentrations at 50% of 

the monitoring sites studied saw small increases from 2013 through 2014; however, the overall 

trend from 2000 through 2014 is decreasing. This ambient data demonstrates the effectiveness of 

the State’s controls in reducing ethylene levels 

C. Permanent and Enforceable Emissions Controls Implemented 

A broad range of control measures have been implemented 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. Table 4 below 

from the report lists existing ozone control strategies that have emissions reductions in the 

attainment demonstrations 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). EPA approved the HGB 1-hour ozone attainment demonstration in 2006 (71 FR 

52670, September 6, 2006) and the HGB 1997 8-hour ozone attainment demonstration in 2014

(79 FR 57, January 2, 2014). 

Table 4. Existing Ozone Control Measures Applicable to the HGB Eight-County 

Nonattainment Area (from section 3.2 of the Redesignation Substitute Report) 

Measure Description Start Date(s)

Highly Reactive Volatile 

Organic Compounds 

Emissions Cap and Trade 

(HECT) Program and 

Highly Reactive Volatile 

Organic Compounds 

(HRVOC) Rules 

30 Texas Administrative 

Code (TAC) Chapter 101, 

Subchapter H, Division 6 

and 30 TAC Chapter 115, 

Subchapter H, Divisions 1 

and 2 

Affects cooling towers, process vents, and 

flares, and establishes an annual emissions 

limit with a cap and trade for each 

applicable site in Harris County 

Seven perimeter counties subject to permit 

allowable limits and monitoring 

requirements 

Monitoring requirements 

began January 31, 2006 

Cap and trade program 

implemented January 1, 

2007 

HECT cap incrementally 

stepped-down from 2014 

through 2017 for a total 

25% cap reduction 

HRVOC Fugitive Rules 

30 TAC Chapter 115, 

Subchapter D, Division 3 

More stringent leak detection and repair 

(LDAR) requirements for components in 

HRVOC service 

Additional components included in LDAR 

program: more stringent repair times, lower 

leak detection, and third-party audit 

requirements 

March 31, 2004 
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Measure Description Start Date(s)

VOC Control Measures – 

Storage Tanks 

30 TAC Chapter 115, 

Subchapter B, Division 1 

Requires controls for slotted guide poles 

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 storage tanks for 

crude oil or natural gas condensate, and 

regulates flash emissions from these tanks 

January 1, 2009 

Compliance with revised 

monitoring and testing 

requirements required by 

March 1, 2013 

VOC Control Measures – 

Degassing Operations 

30 TAC Chapter 115, 

Subchapter F, Division 3 

Requires vapors from degassing to be 

vented to a control device for a longer time 

period, and removes exemption from 

degassing to control for tanks with capacity 

of 75,000 to 1,000,000 gallons 

Clarification of rule and monitoring and 

testing requirements, additional control 

options, and notification requirements 

January 1, 2009 

February 17, 2011 

VOC Control Measures 

30 TAC Chapter 115 

Additional control technology requirements 

for batch processes and bakeries by 

December 31, 2002 

Additional VOC measures adopted earlier 

for reasonably available control technology 

(RACT) purposes: general vent gas control, 

industrial wastewater, loading and 

unloading operations, general VOC LDAR, 

solvent using process, etc. (see Appendix D: 

Reasonably Available Control Technology 

Analysis of the Houston-GalvestonBrazoria Attainment Demonstration State 

Implementation Plan Revision for the 1997 

Eight-Hour Ozone Standard adopted March 

10, 2010 (2010 HGB AD SIP Revision) for 

more details) 

December 31, 2002 and 

earlier 

VOC Control Measures – 

Offset Lithographic 

Printers 

30 TAC Chapter 115, 

Subchapter E, Division 4 

Additional control technology requirements 

for offset lithographic printers 

Revised in 2010 to limit VOC content of 

solvents used by offset lithographic printing 

facilities and to include smaller sources in 

rule applicability (see Appendix D of the 

2010 HGB AD SIP Revision for more 

details) 

December 31, 2002 

March 1, 2011 for major 

sources 

March 1, 2012 for minor 

sources 

VOC Control Measures – 

Solvent-Using Processes 

30 TAC Chapter 115, 

Subchapter E 

Revised in 2011 to implement RACT 

requirements per control technique 

guidelines published by the United States 

Environmental Protection Agency (EPA) 

Seven emission source categories in the 

HGB area: industrial cleaning solvents; 

flexible package printing; paper, film, and 

foil coatings; large appliance coatings; 

March 1, 2013 
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Measure Description Start Date(s)

metal furniture coatings; miscellaneous 

metal and plastic parts coatings; and 

miscellaneous industrial adhesives (see 

Houston-Galveston-Brazoria Reasonably 

Available Control Technology Analysis 

Update State Implementation Plan Revision 

for the 1997 Eight-Hour Ozone Standard 

adopted December 7, 2011 for more details) 

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 the tank truck as the 

storage tank is being filled with fuel, rather 

than released into the ambient air 

1990 

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 a vehicle is 

being fueled at the pump 

Vapors returned through the pump hose to 

the petroleum storage tank, rather than 

released into the air 

1992 

A SIP revision authorizing 

the decommissioning of 

Stage II vapor control 

equipment was submitted 

to the EPA on October 31, 

2013. Facilities may 

continue operating Stage II 

until August 31, 2018. 

Nitrogen Oxides (NOX) 

Mass Emissions Cap and 

Trade (MECT) Program 

and Chapter 117 NOx 

Emission Standards for 

Attainment Demonstration 

Requirements 

30 TAC Chapter 101, 

Subchapter H, Division 3 

and 30 TAC Chapter 117, 

Subchapter B, Division 3 

and Subchapter C, 

Division 3 

Overall 80% NOX reduction from existing 

industrial sources and utility power plants, 

implemented through a cap and trade 

program 

Affects utility boilers, gas turbines, heaters 

and furnaces, stationary internal combustion 

engines, industrial boilers, and many other 

industrial sources 

April 1, 2003 and 

phased in through 

April 1, 2007 

NOX System Cap 

Requirements for Electric 

Generating Facilities 

(EGFs) 

30 TAC Chapter 117, 

Subchapter B, Division 3 

and Subchapter C, 

Division 3 

Mandatory daily and 30-day system cap 

emission limits (independent of the MECT 

Program) for all EGFs at utility power 

plants and certain industrial/commercial 

EGFs that also provide power to the electric 

grid 

March 31, 2007 

(industrial/commercial 

EGFs) 

March 31, 2004 

(utility power plants) 

Utility Electric Generation 

in East and Central Texas 

30 TAC Chapter 117, 

NOX control requirements (approximately 

55 %) on utility boilers and stationary gas 

May 1, 2003 through 

May 1, 2005 
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Measure Description Start Date(s)

Subchapter E, Division 1 turbines at utility electric generation sites in 

East and Central Texas 

NOX Emission Standards 

for Nitric Acid and Adipic 

Acid Manufacturing 

30 TAC Chapter 117, 

Subchapter F 

NOX emission standards for nitric acid and 

adipic acid manufacturing facilities in the 

HGB area 

November 15, 1999 

Stationary Diesel Engines 

30 TAC Chapter 117, 

Subchapter B, Division 3 

and Subchapter D, 

Division 1 

Prohibition on operating stationary diesel 

and dual-fuel engines for testing and 

maintenance purposes between 6:00 a.m. 

and noon 

April 1, 2002 

Natural Gas-Fired Small 

Boilers, Process Heaters, 

and Water Heaters 

30 TAC Chapter 117, 

Subchapter E, Division 3 

NOX 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 

2002 

Minor Source NOX

Controls for Non-MECT 

Sites 

30 TAC Chapter 117, 

Subchapter D, Division 1 

NOX emission limits on boilers, process 

heaters, stationary engines, and turbines at 

minor sites not included in the MECT 

program (uncontrolled design capacity to 

emit less than 10 tons per year) 

March 31, 2005 

Texas Low Emission 

Diesel (TxLED) 

30 TAC Chapter 114, 

Subchapter H, Division 2 

Requires all diesels for both on-road and 

non-road use to have a lower aromatic 

content and a higher cetane number 

October 31, 2005 and 

phased in through January 

31, 2006 

TxLED for Marine Fuels 

30 TAC Chapter 114, 

Subchapter H, Division 2 

Adds marine distillate fuels X and A, 

commonly known as DMX and DMA, or 

Marine Gas Oil, into the definition of diesel 

fuels, requiring them to be TxLED 

compliant 

October 1, 2007 and 

phased in through January 

1, 2008 

Vehicle Inspection/ 

Maintenance 

30 TAC Chapter 114, 

Subchapter C 

Yearly treadmill-type testing for pre-1996 

vehicles and computer checks for 1996 and 

newer vehicles 

May 1, 2002 in Harris 

County 

May 1, 2003 in Brazoria, 

Fort Bend, Galveston, and 

Montgomery Counties 

Texas Low Reid Vapor 

Pressure (RVP) Gasoline 

30 TAC Chapter 114, 

Subchapter H, Division 1 

Requires all gasoline for both on-road and 

non-road use to have a RVP of 7.8 pounds 

per square inch or less from May 1 through 

October 1 each year 

April 2000 

Texas Emissions 

Reduction Plan (TERP) 

30 TAC Chapter 114, 

Subchapter K 

Provides grant funds for on-road and nonroad heavy-duty diesel engine 

replacement/retrofit 

January 2002 

Voluntary Mobile 

Emission Reduction 

Program 

Voluntary measures administered by the 

Houston-Galveston Area Council (H-GAC) 

(see Appendix F: Evaluation of Mobile 

Source Control Strategies for the HoustonGalveston-Brazoria State Implementation 

Phase in through 2018 
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Measure Description Start Date(s)

Plan (With Detailed Strategies), prepared 

for H-GAC by ENVIRON International 

Corporation, of the 2010 HGB AD SIP 

Revision) 

Federal Area/Non-Road 

Measures 

Series of emissions limits, implemented by 

the EPA, for area and non-road sources 

Examples: diesel and gasoline engine 

standards for locomotives and leaf-blowers 

Phase in through 2018 

Federal On-Road 

Measures 

Series of emissions limits, implemented by 

the EPA, for on-road vehicles 

Examples: Tier 1 and Tier 2 vehicle 

standards, low sulfur diesel standards, 

National Low Emission Vehicle standards, 

and reformulated gasoline 

Phase in through 2018 

Speed Limit Reduction 

43 TAC Chapter 25, 

Subchapter B 

Five miles per hour (mph) below what was 

posted before May 1, 2002, on roadways 

where speeds were 65 mph or higher 

September 2003 

California Standards for 

Certain Gasoline Engines 

California standards for non-road gasoline 

engines 25 horsepower and larger 

May 1, 2004 

Transportation Control 

Measures 

Various measures in H-GAC’s long-range 

transportation plans (see Appendix F of the 

2010 HGB AD SIP Revision for more 

details) 

Phase in through 2018 

Voluntary Energy 

Efficiency/Renewable 

Energy 

Energy efficiency and renewable energy 

projects enacted by the Texas Legislature 

outlined in Section 3.3.5: Energy Efficiency 

and Renewable Energy Measures

(Redesignation Substitute Report) 

See Section 3.3.5 of the 

Redesignation Substitute 

Report 

For emissions reductions not included in the 1997 8-hour and 1-hour ozone attainment 

demonstrations Texas identified other permanent and enforceable control measures. These 

measures were: 

• Highly Reactive Volatile Organic Compounds Emissions Cap and Trade Program 

• Mass Emissions Cap and Trade Program 

• Tier 3 Federal Motor Vehicle Emission and Fuel Standards 

• New International Marine Diesel Engine and Fuel Standards for Oceangoing Vessels and 

Emissions Control Areas 

We note that the Clean Air Interstate Rule (CAIR) and the Cross-State Air Pollution Rule (CSAPR) have 

also helped reduce ozone levels in Houston and the eastern U.S. CAIR and CSAPR limited NOx 

emissions from electric generating units in many eastern states, including Texas. CAIR implementation 

ended in 2014 and CSAPR implementation began in 2015 (79 FR 71663, December 3, 2014). For more 

information on CAIR and CSAPR please see our December 3, 2015 CSAPR Update proposal (80 FR 

75706). 

In sum, the table above shows the breadth of controls that have been adopted and implemented in 

the HGB area. These controls have been implemented over a period of decades. Texas has 
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focused on the significant reductions that have happened since 2002, demonstrating both NOx 

and VOCs have declined significantly. During this same time period ozone levels have also 

declined. Table 3 shows that both Federal Measures to control on-road and off-road emissions 

and State instituted controls such as low emission diesel for marine vessels, additional storage 

tank controls and storage tank degassing controls have all contributed to these additional 

reductions. 

Additionally, we note that EPA has approved SIPs for the HGB area that document continuous 

emissions reductions due to permanent and enforceable measures for the 1-hour and 1997 8-hour 

ozone standards (70 FR 7407, February 14, 2005; 74 FR 18298, April 22, 2009; 79 FR 51, 

January 2, 2014). The EPA concludes that the reductions in ozone are due to a these permanent 

and enforceable measures. 

(2) The area will maintain the revoked NAAQS for 10 years from the date of the EPA’s 

approval of the showing.

Consistent with the 1992 redesignations guidance, Texas provided an attainment emissions 

inventory and projected future emissions inventories. To demonstrate maintenance of the 1997 8-

hour ozone standard, the TCEQ projected VOC and NOX emissions to 2028 and to several 

interim years, 2014, 2017, 2020, 2023, 2026 and 2028. These emissions were compared to the 

2012 attainment year emissions to show that emissions of NOX and VOCs, remain below the 

attainment levels for the entire demonstrated maintenance period. 

In the August 18, 2015, ozone redesignation substitute request, the TCEQ compared the VOC 

and NOX emissions for 2012, 2014, 2017, 2020, 2023, 2026 and 2028 for all major source 

sectors, and in total for the HGB nonattainment area. In its ozone maintenance demonstration, 

the TCEQ presented the NOX and VOC emission totals for the 2012 base year and all projection 

years for the HGB area. The TCEQ’s maintenance demonstration shows that in 2014, 2017, 

2020, 2023 and 2026, NOX emission totals for the HGB area are projected to be below the 2012 

NOX emissions for the area, representing a 161 tpd decrease. VOC emissions totals are expected 

to remain relatively flat with an increase of 8.4 tpd. This slight VOC increase still represents a 

decrease from 2011 levels of 23.6 tpd or 4.4%. 

NOX emissions in the HGB area are projected to decline by 39 percent between 2011 and 2028. 

VOC emissions in the HGB area are projected to increase by approximately 1.4 percent between 

2011 and 2028. Based on photochemical modeling analyses showing that the formation of ozone 

in the HGB area is more sensitive to NOX than to VOC emissions, the small increase in VOC 

emissions is expected to be much less significant than the large decrease in NOX. 

Based on this analysis, emissions in the HGB 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 HGB area are shown in Table 5: HGB NOX Emissions by Source 

Category (tons per day) and Table 6: HGB VOC Emissions by Source Category (tons per day). 

Contributions from biogenic emissions were not included in the summary because this analysis 

was limited to anthropogenic sources. 
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Table 5: HGB area NOX Emissions by Source Category (tpd) 

Category 2012 2014 2017 2020 2023 2026 2028 

Point Sources 98.5 119.67 127.39 127.71 128.03 128.35 128.56

Area Sources 21.91 22.52 23.23 23.61 23.47 23.50 23.59

On-Road Mobile 

Sources 

159.08 124.64 82.96 61.06 48.94 40.24 37.04

Non-Road 

Mobile Sources 132.24 100.90 87.32 76.34 69.91 64.78 61.62

Total 411.73 367.73 320.90 288.72 270.35 256.87 250.81

Table 6: HGB area VOC Emissions by Source Category (tpd) 

Category 2012 2014 2017 2020 2023 2026 2028 

Point Sources 84.06 110.72 115.02 115.65 116.26 116.94 117.41 

Area Sources 310.07 317.75 328.20 335.07 337.81 341.16 344.75 

On-Road Mobile 

Sources 

74.51 61.48 47.36 40.38 36.12 31.71 28.99 

Non-Road Mobile 

Sources 44.01 38.81 33.51 30.89 30.05 29.84 29.93 

Total 512.65 528.76 524.09 521.99 520.24 519.65 521.08 

Trend analysis using the 2028 future year emissions shows an overall decrease of 152.49 tpd in 

combined NOX and VOC emissions for the HGB area. This net change includes a projected 8.43 

tpd increase in VOC and a 160.92 tpd decrease in NOX from 2012 levels. 

In general, growth in point and area source emissions 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 HGB area through projections of 

VOC and NOX emissions that show that the emissions will remain below the 2012 attainment 

levels during the maintenance period. 

D. The Effects of a Redesignation Substitute Final Action in HGB 

Texas has requested that EPA concur 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 redesignation substitute, the state may request to revise 

its SIP to revise or remove provisions for NNSR for the revoked 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 HGB area, EPA believes that a SIP revision in this 

particular case is not necessary because the ozone standards in question have been revoked and 
15

because of a provision in the Texas SIP which changes the designation of the area to what is 

listed in 40 CFR part 81. We believe a plain reading of this provision in the Texas SIP 

establishes an area’s classification and thus the related major source thresholds and offset ratios 

for Texas as part 81 is updated without further action by Texas. Any other anti-backsliding 

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 Rules, Subchapter A: General Rules , §101.1. 

Definitions. (71) Nonattainment area--A defined region within the state that is 

designated by the United States Environmental Protection Agency (EPA) as failing to 

meet the national ambient air quality standard (NAAQS or standard) for a pollutant for 

which a standard exists. The EPA will designate the area as nonattainment under the 

provisions of 42 United States Code, §7407(d). For the official list and boundaries of 

nonattainment areas, see 40 Code of Federal Regulations (CFR) Part 81 and pertinent 

Federal Register notices. The designations and classifications for 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 the EPA that any requirement is no longer 

required for purposes of anti-backsliding, then that requirement no longer applies.  

NNSR Offset Ratios and Major Source Thresholds are defined in TAC Chapter 116 

Control of Air Pollution by Permits for New Construction or Modification, Subchapter A: 

Definitions, §116.12. Nonattainment and Prevention of Significant Deterioration Review 

Definitions (19) Major Stationary Source and (20) Major Modification. Both definitions 

refer to Table 1 below. 

TABLE I3

MAJOR SOURCE/MAJOR MODIFICATION 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, HGB is still subject to Nonattainment 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. 

                                                            

3

 Only Ozone is included here 
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Conclusion

The review of the Texas redesignation substitute report found that Texas has demonstrated that: 

(1) The HGB area has attained the revoked 1997 8-hour ozone NAAQS due to permanent 

and enforceable emission reductions 

(2) The HGB area will maintain the revoked 1997 8-hour ozone NAAQS for ten years from 

the date of the EPA’s approval of this demonstration. 

EPA is proposing to approve the HGB redesignation substitute for the revoked 1997 8-hour 

ozone NAAQS. Upon final approval of the redesignation substitute, the area’s NNSR 

classification will be determined by the next highest classification remaining for that area.