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Technical Support Document

Houston-Galveston-Brazoria Redesignation Substitute

Background

Evaluation

Conclusion

June 2015

FOR FURTHER INFORMATION CONTACT: Tracie Donaldson, United States 

Environmental Protection Agency Region 6, Air Quality Section (6PD-A). 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 1-hour ozone nonattainment area (HGB area) has attained the revoked 1-

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 One-Hour 

Ozone Standard Nonattainment Area” (Redesignation Substitute Report) submitted to EPA on 

July 22, 2014. 

The determination that the area has attained the 1-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 1-hour ozone NAAQS for the 2011–2013 monitoring period. 

The ozone monitoring data for 2014 in AQS indicate that the area continues in attainment for the 

1-hour standard. Available data for 2015 shows that the area continues to attain the 1-hour 

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

determination that the area attained the 1-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.

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 billion (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 records a 1-

hour average ozone concentration above 0.12 ppm in any given day. Only the highest 1-hour 

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 ozone 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 quality 

standards for ozone’’ (40 CFR 50.9) and ‘‘Interpretation of the 1-Hour Primary and Secondary 

National Ambient Air Quality Standards for ozone’’ (40 CFR Part 50, Appendix H). 

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 

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 Act, as amended in 1990, required the EPA to designate as nonattainment any area that was 

violating the 1-hour ozone standard, generally based on air quality monitoring data from the 

1987 through 1989 period (section 107(d)(4) of the Act; 56 FR 56694, November 6, 1991). The 
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Houston area was designated nonattainment with a severe classification at that time and an 

attainment date of no later than November 15, 2007.

The EPA revoked the 1-hour ozone standard on April 30, 2004 in favor of the 1997 8-hour ozone 

standard (69 FR 23951), and, on March 6, 2015, the EPA revoked the 1997 8-hour standard in 

favor of the more stringent 2008 8-hour ozone 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.

EPA indicated in the revised Phase 1 rule that these criteria were based on the provisions of 

CAA section 107(d)(3)(E). Specifically, 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 July 22, 2014, the Texas Commission on Environmental Quality (TCEQ) provided the 

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

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

redesignation substitute for the 1-hour ozone standard obligations for 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.

Evaluation

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

reductions.

a.) Is the HGB area attaining the 1-hour ozone NAAQS?

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

that show that the area is currently attaining the 1-hour ozone NAAQS, consistent with 40 CFR 

Part 50, Appendix H.
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Table 1: Current 1-hour Ozone NAAQS Design Values for the HGB Area

Years 1- Hour Ozone 

Design Value

2011-2013 121 ppb

2012-2014 111 ppb

Preliminary 

2013-2015 

(6/8/15)

107 ppb

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

For the one-hour ozone NAAQS, the design value was used to determine the classification of a 

nonattainment area but was not used for designating an area as attainment or otherwise. 

Designation is based on the maximum number of expected exceedances over all the monitors in 
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an area1. To show that the HGB area no longer violates the one-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 spatially, it is also prudent to investigate trends 

at all regulatory monitors in an area. Table 2: One-Hour Ozone Expected Exceedances by 

Monitor contains one-hour ozone expected number of exceedances at all regulatory monitors in 

the HGB area from 2011 through 2014. More monitors than those listed in Table 2 operate in the 

HGB area, but expected number of exceedances at those additional monitors are not appropriate 

for compliance determinations because the monitors’ data do not meet EPA’s quality assurance 

criteria and cannot be used for regulatory purposes. In 2013, all monitors in the HGB area had 

expected exceedances less than the threshold of 1.0 per year and only one monitor in the HGB 

area, the Houston East monitor (C1), had more than 1.0 expected exceedance in 2011 and 2012.

 

1 The expected exceedances for a monitor is defined as the number of exceedances that occurred in the calendar year 

plus an increment that accounts for missing data, averaged across three consecutive years (for example, expected 

exceedances for 2013 is averaged across 2011, 2012, and 2013). The increment 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 individual monitor. Note that unlike the 

calculation for expected exceedances, design values are not adjusted for data completeness.
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Table 2. One-Hour Ozone Expected Exceedances by Monitor 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 1-hour ozone standard.

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 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 

2011 2012 2013 2014 2011-2013 2012-2014

Manvel Croix Park C84 (480391004) 1 1.1 0 1.0 0.7 0.7

Houston East C1 (482011034) 2 0 0 0.0 0.7 0.0

Northwest Harris County C26 (482010029) 0 2 0 0.0 0.7 0.7

Houston Bayland Park C53 (482010055) 1 1 0 0.0 0.7 0.3

Houston Monroe C406 (482010062) 0 2 0 0.0 0.7 0.7

Seabrook Friendship Park C45 (482011050) 0 1 1 0.0 0.7 0.7

Galveston 99th St C1034 (481671034) 1.1 0 0 0.0 0.4 0.0

Park Place C416 (482010416) 0 1 0 0.0 0.3 0.3

Houston Aldine C8/C108/C150 (482010024) 1 0 0 0.0 0.3 0.0

Houston Croquet C409 (482010051) 0 1 0 0.0 0.3 0.3

Houston Texas Avenue C411 (482010075) 0 1 0 0.0 0.3 0.3

Cinton c403/C113/C3 (482011035) 0 1 0 0.0 0.3 0.3

Houston North Wayside C405 (482010046) 1 0 0 0.0 0.3 0.0

Channelview C15/C115 (482010026) 0 0 0 0.0 0.0 0.0

Lynchburg Ferry C1015 (482011015) 0 0 0 0.0 0.0 0.0

Houston Deer Park 2 C35/C139 (482011039) 0 0 0 0.0 0.0 0.0

Lang C408 (482010047) 0 0 0 0.0 0.0 0.0

Lake Jackson C1016 (480391016) 0 0 0 0.0 0.0 0.0

Houston Westhollow C410 (482010066) 0 0 0 0.0 0.0 0.0

Conroe Relocated C78 (483390078) 0 0 0 0.0 0.0 0.0

HGB Monitoring Site (AQS #)

Expected Exceedances by Year 3 years Expected 

Exceedances (avg.)
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2002 and the period in which the standard was attained, 2011-2013. 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 2011 because it is the year of the most recent periodic emissions 

inventory (PEI) and one of the three years used to determine the design value (DV) for the 2013 

attainment year. 2011 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. 2011 is the first three-year period demonstrating 

attainment. By 2011, 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 2011 base year emission 

inventories below.

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

(2002) and the attainment year (2011), 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. 

Table 3: HGB Eight-County Nonattainment Area Historical Emissions

Emissions Source Category 2002 2005 2008 2011

VOC Emissions (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
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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 1-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 2013. Annual maxima, annual 

90th percentile and annual average daily peak 1-hour NOX values were analyzed. All three 

measures decreased markedly over the time period from 2000 to 2013, falling 25% (maximum), 

24% (90th percentile) and 28% (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 

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 2013 when the geometric mean ethylene increased. Ethylene at the Houston 

Regional Monitoring Corporation (HRM) 3 Haden Road non-regulatory, industry-sponsored 

monitor (C603) began increasing in 2011 and 2012 but resumed its decreasing trend in 2013. 

Ethylene is a highly reactive VOC shown to disproportionately impact ozone levels. 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 1-hour ozone NAAQS. Table 4 below from 

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

NOX Mass Emissions Cap and 

Trade (MECT) Program 

30 Texas Administrative 

Code (TAC) Chapter 101, 

Subchapter H, 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

HRVOC Rules and Highly 

Reactive Volatile Organic 

Compounds Emissions Cap 

and Trade (HECT) Program 

30 TAC Chapter 101, 

Subchapter H, Division 6

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

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

NOX Emission Standards for 

Nitric Acid and Adipic Acid 

Manufacturing 

NOX emission standards for nitric acid and 

adipic acid manufacturing facilities in the HGB 

area

November 15, 1999
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Measure Description Start Date(s)

30 TAC Chapter 117, 

Subchapter F

Utility Electric Generation in 

East and Central Texas 

30 TAC Chapter 117, 

Subchapter E, Division 1

NOX control requirements (approximately 55 %) 

on utility boilers and stationary gas turbines at 

utility electric generation sites in East and 

Central Texas

May 1, 2003 through May 1, 

2005

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; 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) 

March 1, 2013 

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 

Refueling – Stage II Captures gasoline vapors when a vehicle is 

being fueled at the pump 

1992 
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Measure Description Start Date(s)

30 TAC Chapter 115, 

Subchapter C, Division 4 

Vapors returned through the pump hose to the 

petroleum storage tank, rather than released 

into the air 

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. 

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 

Through 2018 

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 

January 2002 

California Standards for 

Certain Gasoline Engines 

California standards for non-road gasoline 

engines 25 horsepower and larger 

May 1, 2004 

Stationary Diesel Engines 

30 TAC Chapter 117, 

Subchapter B, Division 3 

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 nonroad use to have a lower aromatic content and 

a higher cetane number 

Phase in began October 31, 

2005 

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 

June 24, 2007 

Texas Low Reid Vapor 

Pressure (RVP) Gasoline 

30 TAC Chapter 114, 

Subchapter H, Division 1 

Requires all gasoline for both on-road and nonroad use to have a RVP of 7.8 pounds per 

square inch or less from May 1 through October 

1 each year 

April 2000 

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 Houston-GalvestonBrazoria State Implementation Plan (With 

Detailed Strategies), prepared for H-GAC by 

ENVIRON International Corporation, of the 2010 

HGB AD SIP Revision) 

Through 2018 
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Measure Description Start Date(s)

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 2013 

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 

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 

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 encouraged by Senate Bill (SB) 7, 76th 

Texas Legislature, 1999 and SB 5, 77th Texas 

Legislature, 2001 

September 1, 1999 and 

September 1, 2001 

Automotive Windshield 

Washer Fluid 

30 TAC Chapter 115, 

Subchapter G, Division 1 

VOC content limitation on automotive 

windshield washer fluid sold, supplied, 

distributed, or manufactured for use in Texas 

January 1, 1995 

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: 

• Control of Volatile Organic Compounds Emissions from Storage Tanks

• Mass Emissions Cap and Trade Program for NOx

• Tier 3 Federal Motor Vehicle Emission and Fuel Standards

• Federal Marine Diesel Engine and Fuel Standards

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

the HGB area. These controls have been implanted over a period of decades. Texas has 

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 2 shows that the precursor reductions have continued from 2008 forward as well

as providing the additional improvement in ozone levels necessary to reach attainment. Tables 3 

and 4 show 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 we’ve 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 
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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 1-hour 

ozone standard, the TCEQ projected VOC and NOX emissions to 2026 and to several interim

years, 2014, 2017, 2020 and 2023. These emissions were compared to the 2011 attainment year 

emissions to show that emissions of NOX and VOC, remain below the attainment levels for the 

entire demonstrated maintenance period.

In the July 22, 2014, ozone redesignation substitute request, the TCEQ compared the VOC and

NOX emissions for 2011, 2014, 2017, 2020, 2023 and 2026 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 2011 base year and all projection years for 

the HGB area. The TCEQ’s maintenance demonstration shows that in 2014, 2017, 2020, 2023 

and 2026, VOC and NOX emission totals for the HGB area are projected to be below the 2011

VOC and NOX emissions for the area.

NOX emissions in the HGB area are projected to decline by 37 percent between 2011 and 2026.

VOC emissions in the HGB area are projected to decline by approximately 3.5 percent between 

2011 and 2026. 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 decrease in VOC 

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

Based on this analysis, emissions in the HGB area are expected to remain at levels consistent 

with attainment for the 1-hour ozone standard from 2014 through 2026.

The 2011 base year and the 2014, 2017, 2020, 2023, and 2026 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 are not included in the summary because this analysis is 

limited to anthropogenic sources. 

Table 5: HGB area NOX Emissions by Source Category (tpd)

Category 2011 2014 2017 2020 2023 2026 

Point Sources 108.48 126.31 126.82 127.01 127.20 127.39 

Area Sources 21.15 22.19 22.90 23.28 23.17 23.23 

On-Road Mobile Sources 181.28 127.70 88.85 69.80 59.28 54.51 

Non-Road Mobile Sources 

121.11 106.99 94.99 83.70 75.54 68.98 
14

Total 432.02 383.19 333.56 303.79 285.19 274.11 

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

Category 2011 2014 2017 2020 2023 2026 

Point Sources 96.11 100.81 102.86 103.29 103.71 104.12 

Area Sources 308.74 321.92 332.43 339.67 342.58 346.13 

On-Road Mobile Sources 80.92 60.43 46.51 40.51 38.09 36.93 

Non-Road Mobile Sources 

49.92 38.33 33.34 30.86 30.11 30.02 

Total 535.69 521.49 515.14 514.33 514.49 517.20 

Trend analysis using the 2026 future year emissions shows an overall decrease of 176.40 tpd in 

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

18.49 tpd decrease in VOC and a 157.91 tpd decrease in NOX from 2011 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 2011 attainment 

levels during the maintenance period.

Conclusion

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

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

enforceable emission reductions

(2) The HGB area will maintain the revoked 1-hour ozone NAAQS for ten years from the 

date of the EPA’s approval of this demonstration.

It is recommended that EPA approve the HGB redesignation substitute for the revoked 1-hour 

ozone NAAQS.