Bryan W. Shaw, Ph.D., P.E., Chairman 

Toby Baker, Commissioner 

Richard A. Hyde, P.E., Executive Director 15 AUG 26 PM 5: 24 

TEXAS COMMISSION ON ENVIRONMENTAL QUALITY 

Protecting Texas by Reducing and Preventing Pollution 

August 18, 2015 

Mr. Ron Curry 

Regional Administrator 

Environmental Protection Agency, Region 6 

Fountain Place 12th Floor, Suite 1200 

1445 Ross Avenue 

Dallas, Texas 75202-2733 

Subject: Redesignation Substitute Reports for the Houston-Galveston-Brazoria (HGB) 

1997 Eight-Hour Ozone Standard Nonattainment Area and the Dallas-Fort 

Worth (DFW) One-Hour and 1997 Eight-Hour Ozone Standard Nonattainment 

Areas 

Dear Mr. Curry: 

The Texas Commission on Environmental Quality (TCEQ) submits the enclosed Redesignation 

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

Nonattainment Area and the Redesignation Substitute Report for the Dallas-Fort Worth OneHour and 1997 Eight-Hour Ozone Standard Nonattainment Areas for your consideration and 

concurrence that the HGB area has met the requirements for the 1997 eight-hour ozone 

National Ambient Air Quality Standard (NAAQS) and that the DFW areas have met the 

requirements for both the one-hour and 1997 eight-hour ozone NAAQS. 

These redesignation substitute reports include: monitoring data showing attainment of the 

relevant ozone NAAQS; a showing that attainment was due to permanent and enforceable 

emissions reductions; and, a demonstration that the areas can maintain the standards through 

2028 based on emission inventory trends and projections of future emissions. 

The United States Environmental Protection Agency's (EPA) Implementation of the 2008 

National Ambient Air Quality Standafds for Ozone: State Implementation Plan Requirements; 

Final Rule (2008 ozone standard SIP requirements rule) published in the March 6, 2015 

Federal Register (8o FR 12264), includes a mechanism for lifting anti-backsliding obligations 

under a revoked ozone NAAQS. According to the rule, a state can provide a showing, termed a 

redesignation substitute, based on Federal Clean Air Act (FCAA), §107(d)(3)(E) redesignation 

criteria to demonstrate that an area qualifies for lifting anti-backsliding obligations under a 

revoked standard. The enclosed reports fulfill the requirements for a redesignation substitute, as 

described in the 2008 ozone standard SIP requirements rule, for the HGB 1997 eight-hour 

ozone nonattainment area and the DFW one-hour and 1997 eight-hour ozone nonattainment 

areas. 

The DFW one-hour ozone nonattainment area comprises Collin, Dallas, Denton, and Tarrant 

Counties. The DFW four-county area monitored attainment of the one-hour ozone NAAQS 

based on certified monitoring data from 2004 through 2006 and has continued to monitor 

P.O. Box 13087 • Austin, Texas 78711-3087 • 512-239-1000 • tceq.texas.gov 

How is our customer service? tceq.texas.gov /customersurvey 

printed on recycled paper using vegetable-based ink 
Mr. Ron Curry 

Page 2 

August 18, 2015 

attainment since that time. On October 16, 2008, the EPA published final determination ( 73 FR 

61357) that the DFW four-county nonattainment area had attained the one-hour ozone 

standard. The DFW four-county area has continued to monitor attainment of the one-hour 

ozone NAAQS since 2006. 

The DFW 1997 eight-hour ozone nonattainment area comprises Collin, Dallas, Denton, Ellis, 

Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties. The HGB 1997 eight-hour ozone 

nonattainment area comprises Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, 

Montgomery, and Waller Counties. The TCEQ submitted early certification of 2014 ozone air 

monitoring data to the EPA on February 24, 2015, and a request for a determination of 

attainment for both the DFW and HGB eight-hour ozone nonattainment areas on February 27, 

2015. On April 28, 2015, the EPA published a proposed clean data determination for the D FW 

1997 eight-hour ozone nonattainment area (So FR 23487). On June 10, 2015, the EPA verified 

that the 2014 ambient ozone monitoring data for the HGB area met all data quality 

requirements for attaining the 1997 eight-hour ozone NAAQS. As of August 18, 2015, the DFW 

and HGB areas continue to monitor attainment of the 1997 eight-hour ozone standard. 

Title 40 Code of Federal Regulations §51.1105(b)(2) allows the EPA to remove the provisions for 

nonattainment new source review for the revoked one-hour and 1997 eight-hour ozone NAAQS 

upon the EPA's approval of the 1997 eight-hour ozone HGB redesignation substitute and the 

DFW one-hour and 1997 eight-hour redesignation substitute. With these redesignation 

substitutes, the TCEQ requests that the EPA concur that the HGB and DFW areas are attaining 

and will continue to attain the revoked one-hour and revoked 1997 eight-hour ozone NAAQS, 

and that the relevant nonattainment NSR provisions no longer apply to the areas. 

If you have questions or need additional information, please contact David Brymer, Director of 

the Air Quality Division, at (512) 239-1725. 

~fi .. .R_z_ 

Richard A. Hyde,~, Executive Director 

Texas Commission on Environmental Quality 

RH/DB/lb/mr 

Enclosures: Redesignation Substitute Report for the Houston-Galveston-Brazoria 1997 EightHour Ozone Standard Nonattainment Area 

Redesignation Substitute Report for the f!allas-Fort Worth One-Hour and 1997 EightHour Ozone Standard Nonattainment Areas 
REDESIGNATION SUBSTITUTE REPORT FOR THE

HOUSTON-GALVESTON-BRAZORIA 1997 EIGHT-HOUR OZONE 

STANDARD NONATTAINMENT AREA

TEXAS COMMISSION ON ENVIRONMENTAL QUALITY

P.O. BOX 13087

AUSTIN, TEXAS 78711-3087
This page intentionally left blank
Page 1

SECTION 1: GENERAL

1.1 Purpose of this Redesignation Substitute Report

This redesignation substitute (RS) report for the Houston-Galveston-Brazoria (HGB) Area 1997 

eight-hour ozone National Ambient Air Quality Standard (NAAQS) supports the requirements 

described in the EPA’s Implementation of the 2008 National Ambient Air Quality Standards 

for Ozone: State Implementation Plan Requirements; Final Rule (2008 ozone standard SIP 

requirements rule), published in the Federal Register (FR) on March 6, 2015 (80 FR 12264). 

Certified monitoring data for 2012 through 2014 show the HGB area, which includes Brazoria, 

Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties, monitored

attainment of the 1997 eight-hour ozone NAAQS with a design value of 80 parts per billion 

(ppb). The TCEQ submitted early certification of 2014 ozone air monitoring data to the EPA on

February 24, 2015, and a request for a finding of attainment for the HGB area for the revoked 

1997 eight-hour ozone NAAQS on February 27, 2015. On June 10, 2015, the EPA verified that 

the 2014 ambient air monitoring data for ozone met all data quality requirements for attaining 

the 1997 eight-hour ozone NAAQS. On August 3, 2015, the EPA Region 6 Administrator, Ron 

Curry, signed the proposed determination of attainment of the 1997 eight-hour ozone standard 

for the HGB area. As of August 4, 2015, the HGB area continues to monitor attainment of the 

revoked 1997 eight-hour ozone NAAQS.

The EPA’s 2008 ozone standard SIP requirements rule includes a mechanism for lifting antibacksliding obligations under a revoked ozone NAAQS. According to the EPA’s 2008 ozone 

standard SIP requirements rule, a state can provide a showing, termed a redesignation 

substitute, based on Federal Clean Air Act (FCAA), §107(d)(3)(E) redesignation criteria to 

demonstrate that an area qualifies for lifting anti-backsliding obligations under a revoked 

standard.

This HGB RS report is intended to satisfy the EPA’s requirements to lift anti-backsliding 

obligations for the revoked 1997 eight-hour ozone NAAQS by ensuring that specific 

redesignation requirements are met for the HGB area. This HGB RS report will be submitted to 

the EPA as provided in the 2008 ozone standard SIP requirements rule instead of a 

redesignation request and maintenance plan, which the FCAA required to remove antibacksliding obligations under a standard that has not been revoked.

Title 40 Code of Federal Regulations (CFR) §51.1105(b)(2) allows the EPA to remove the 

provisions for nonattainment new source review (NSR) for the revoked 1997 eight-hour ozone 

NAAQS upon the EPA’s approval of the 1997 eight-hour ozone HGB redesignation substitute. 

With this redesignation substitute, the TCEQ requests that the EPA concur that the HGB area is 

attaining and will continue to attain the revoked 1997 ozone NAAQS, and that the relevant 

nonattainment NSR provisions no longer apply to the area.

Certified ambient air quality monitoring data for 2012 through 2014 demonstrate that the HGB 

area is monitoring attainment of the 1997 eight-hour ozone NAAQS with a design value of 80 

ppb. This HGB RS report further supports the demonstration that the HGB area will continue to 

attain the 1997 eight-hour ozone NAAQS due to permanent and enforceable emission reductions

and demonstrates continued attainment of the 1997 eight-hour ozone NAAQS through 2028 via 

emission inventory trends, 2012 attainment inventory, and projected future emissions. Since 

removing anti-backsliding obligations is contingent upon the EPA’s approval, the TCEQ has set 

a horizon year of 2028. This 10-year period also aligns with the EPA’s requirement of 

maintenance plans to demonstrate attainment for a 10-year period following the date of 

redesignation.
Page 2

This HGB RS report for the 1997 eight-hour ozone NAAQS is based on the EPA’s 2008 ozone 

standard SIP requirements rule. This HGB RS report includes the following elements.

Monitoring Data Showing Attainment of the Revoked 1997 Eight-Hour Ozone NAAQS

Chapter 2: Air Quality Data includes monitoring network and reporting requirements as well as 

ozone data and trend analyses. The certified 2012 through 2014 monitoring data demonstrate 

that the HGB area is monitoring attainment of the 1997 eight-hour ozone NAAQS of 0.08 parts 

per million (ppm) or 84 ppb with a design value of 80 ppb. Ozone concentrations have 

decreased nearly 33% in the HGB area from 1990 through 2014. Examination of the trends in 

eight-hour ozone design values reveals substantial downward trends in monitored ozone levels.

Showing That Attainment Was Due to Permanent and Enforceable Emissions Reductions

Chapter 3: Permanent and Enforceable Emissions Reductions identifies permanent and 

enforceable control measures that have resulted in reductions in nitrogen oxides (NOX) and 

volatile organic compounds (VOC) emissions, and air quality improvements in the HGB 1997 

eight-hour ozone nonattainment area. The 30 Texas Administrative Code (TAC) Chapter 115, 

Control of Air Pollution from Volatile Organic Compounds and 30 TAC Chapter 117, Control of 

Air Pollution from Nitrogen Compounds regulations along with implementation of the HighlyReactive Volatile Organic Compounds Emissions Cap and Trade (HECT) Program and the Mass 

Emissions Cap and Trade (MECT) Program have significantly reduced overall ozone precursor 

emissions at both major and minor stationary sources in the HGB ozone nonattainment area. 

The HGB area has attained the 1997 eight-hour ozone NAAQS as the result of implemented 

federal, state, and local controls. These enforceable measures will remain in place to ensure 

continued maintenance of the 1997 eight-hour ozone NAAQS in the HGB area.

Demonstration That the Area Can Maintain the Standard Over the Next 10 Years

Chapter 4: Maintenance Demonstration provides emissions inventory trends, the 2012

attainment inventory, projected future emissions, and demonstrates continued attainment of 

the 1997 eight-hour ozone standard through 2028. Analysis of projected ozone precursor 

emissions from 2012 through 2028 shows an overall projected decrease of 152.49 tons per day 

(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 2011 through 2028.

Based on emissions projections and previous photochemical analysis, continued attainment of 

the 1997 eight-hour ozone standard is shown for the HGB area through 2028.

1.2 1997 Eight-Hour Ozone NAAQS History

On July 18, 1997, the EPA published the revised NAAQS for ground-level ozone in the Federal

Register (62 FR 38856), and it became effective on September 16, 1997. The EPA phased out 

and replaced the previous one-hour ozone NAAQS with an eight-hour NAAQS set at 0.08 ppm 

based on the three-year average of the annual fourth-highest daily maximum eight-hour average 

ozone concentrations measured at each monitor within an area.

Effective June 15, 2004, Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, 

Montgomery, and Waller Counties were designated nonattainment in the first phase of the 

EPA's implementation rule for the 1997 eight-hour ozone NAAQS (69 FR 23951). The HGB area 

was classified moderate nonattainment for the standard, with an attainment deadline of June 

15, 2010. The TCEQ was required to submit a state implementation plan (SIP) revision for the 

1997 eight-hour ozone NAAQS to the EPA by June 15, 2007. The EPA addressed the control 

obligations that apply to areas designated nonattainment for the 1997 eight-hour ozone NAAQS 

in the second phase of the implementation rule (70 FR 71612).
Page 3

The commission adopted the 2007 HGB 1997 Eight-Hour Ozone Nonattainment Area SIP 

revision on May 23, 2007 as the first step in addressing the 1997 eight-hour ozone NAAQS in the 

HGB area. The revision included additional Voluntary Mobile Source Emissions Reduction 

Program (VMEP) commitments, an analysis of reasonably available control technology (RACT), 

and the Texas 2002 Periodic Emissions Inventory for the HGB ozone nonattainment area. The 

SIP revision also incorporated amendments to 30 TAC Chapter 114, relating to the Texas low 

emission diesel (TxLED) rule for certain marine fuels and 30 TAC Chapter 115, relating to the 

control of emissions of VOC from storage and degassing operations in the HGB area. On April 2, 

2013, the EPA published approval of portions of the RACT analysis for certain VOC categories 

and the VMEP commitments (applicable through 2009) in the 2007 SIP revision (78 FR 19599). 

The EPA published approval of the remaining source categories that were not previously 

approved as meeting RACT requirements on April 15, 2014 and March 27, 2015 (79 FR 21144 

and 80 FR 16291).

The commission also adopted the 2007 HGB 1997 Eight-Hour Ozone Nonattainment Area 

Reasonable Further Progress (RFP) SIP revision on May 23, 2007, which demonstrated that a 

required 15% emissions reduction in ozone precursors (VOC and NOX) would be met for the 

2001 through 2008 RFP analysis period. On April 22, 2009, the EPA published approval of this 

SIP revision, the associated motor vehicle emission budgets (MVEB), and the 2002 base year 

emissions inventory (74 FR 18298).

On June 15, 2007, the state requested that the HGB area be reclassified from a moderate to a 

severe nonattainment area for the 1997 eight-hour ozone NAAQS, with an attainment deadline 

of June 15, 2019. On December 31, 2007, the EPA published its proposal to grant the governor's 

request and took comments on a range of dates for the state to submit a revised SIP (72 FR 

74252). The TCEQ provided comments to the EPA that supported the reclassification and 

justification for an April 2010 SIP submission date. On October 1, 2008, the EPA published 

approval of the governor's request to voluntarily reclassify the HGB ozone nonattainment area 

from a moderate to a severe nonattainment area for the 1997 ozone NAAQS (73 FR 56983) 

effective October 31, 2008. The EPA set April 15, 2010 as the date for the state to submit a 

revised SIP addressing the severe-ozone nonattainment requirements and set a new attainment 

deadline of June 15, 2019.

On March 10, 2010, the commission adopted two revisions to the Texas SIP for the HGB ozone 

nonattainment area. The 2010 HGB Attainment Demonstration SIP Revision for the 1997 EightHour Ozone Standard (2010 HGB AD SIP Revision) included a photochemical modeling 

analysis and a weight of evidence analysis to demonstrate attainment of the 1997 eight-hour 

ozone NAAQS by the June 15, 2019 deadline. This SIP revision also included MVEBs, VOC and 

NOX RACT analyses, reasonably available control measures analysis, and a contingency plan. In 

addition, this SIP revision incorporated revisions to 30 TAC Chapters 101 and 115, also adopted 

on March 10, 2010, which include the MECT Program Cap Integrity, the HECT Program Cap 

Reduction and Allowance Reallocation, and the VOC Control Techniques Guidelines (CTG) 

Update for offset lithographic printing. On April 2, 2013, April 15, 2014, August 4, 2014, and 

March 27, 2015, the EPA published its approvals of the RACT analysis for all affected VOC and 

NOX emissions sources in the HGB area for the 1997 eight-hour ozone NAAQS (78 FR 19599, 79 

FR 21144, 79 FR 45105, and 80 FR 16291). On January 2, 2014, the EPA published its approval 

of the 2010 HGB AD SIP Revision and revisions to the MECT and HECT Programs (79 FR 57).

The 2010 HGB RFP SIP Revision for the 1997 Eight-Hour Ozone Standard, as required by the 

EPA, demonstrated that an 18% emissions reduction requirement will be met for the 2002 

through 2008 RFP analysis period and that an average of 3% per year emissions reduction will 

occur between each of the milestone years 2008, 2011, 2014, 2017, and 2018. This SIP revision 
Page 4

established baseline emission levels, calculated reduction targets, identified control strategies to 

meet emission target levels, and tracked actual emission reductions against established 

emissions growth. This revision also included an MVEB for each milestone year and a 

contingency plan. On January 25, 2011, the EPA published a notice of its determination that the 

MVEBs in the March 10, 2010 SIP revisions, which were developed using the on-road mobile 

source emissions inventories based on the EPA's MOBILE 6.2 model, were adequate for 

transportation conformity purposes (76 FR 4342). On January 2, 2014, the EPA published 

approval of this RFP SIP revision (79 FR 51).

On December 7, 2011, the commission adopted the 2011 HGB RACT Analysis Update SIP 

Revision for the 1997 Eight-Hour Ozone Standard. This SIP revision updated the RACT analysis 

for VOC emission sources to include the seven CTG documents issued by the EPA from 2006 

through 2008 that were not addressed in the 2010 HGB AD SIP Revision. This SIP revision 

incorporated concurrent CTG-related rulemaking that revised Chapter 115, Subchapter E to 

implement RACT for those CTG emission source categories in the HGB area. On March 27, 

2015, the EPA published its approval of this SIP update revision (80 FR 16291).

On April 23, 2013, the commission adopted the 2013 HGB 1997 Eight-Hour Ozone Standard 

Nonattainment Area MVEB Update SIP Revision. This SIP revision updated on-road mobile 

source emissions inventories and MVEBs for the HGB area using the Motor Vehicle Emissions 

Simulator (MOVES) 2010a version of the EPA's mobile emissions estimation model. The 2013

SIP revision also met the primary obligation of the mid-course review commitment in the 2010 

HGB AD SIP Revision by demonstrating that the outstanding 3% contingency requirement was 

fulfilled. Updated on-road inventories and emissions analysis based on the EPA’s August 30, 

2012 vehicle miles traveled offset guidance and a modified version of the MOVES model 

demonstrated compliance with FCAA requirements for transportation control measures in 

severe nonattainment areas. On January 2, 2014, the EPA published approval of this MVEB SIP 

update revision to the 2010 HGB AD SIP Revision (79 FR 57).

1.3 One-Hour Ozone NAAQS Redesignation Substitute

In 1997, the one-hour ozone NAAQS was replaced by the eight-hour ozone NAAQS. Although 

the one-hour standard has been revoked, states must continue to meet one-hour ozone antibacksliding requirements described in 40 CFR §51.905(a). The HGB area (Brazoria, Chambers, 

Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties) is also classified as 

severe nonattainment for the one-hour ozone NAAQS with a June 15, 2007 attainment date; 

however, the HGB area did not monitor attainment by that date. The EPA published a failure-toattain determination in the February 1, 2012 Federal Register (77 FR 3640).

As part of the transition to the 1997 eight-hour ozone standard, the EPA created a submittal 

termed a termination determination to address anti-backsliding requirements for the one-hour 

ozone standard. In May 2010, the TCEQ requested a determination regarding termination of the 

one-hour ozone anti-backsliding obligations associated with the transition from the one-hour 

ozone standard to the 1997 eight-hour ozone standard. As a result of court action, the EPA was 

unable to propose approval of the request.

1 Consequently, on May 22, 2013, the commission 

 1 On July 1, 2011, the District Court of Columbia Circuit Court of Appeals vacated EPA’s memorandum 

“Guidance on Developing Fee Programs Required by Clean Air Act Section 185 for the one-hour ozone 

NAAQS,” ruling that the EPA’s suggested alternative relating to attainment of the eight-hour ozone 

standard was not consistent with the FCAA.
Page 5

adopted the Severe Ozone Nonattainment Area Failure to Attain Fees rulemaking (Rule Project 

No. 2009-009-101-AI) to implement the §185 penalty fee.

Based on 2011 through 2013 monitoring data, the average number of exceedances of the 0.12 

ppm one-hour ozone NAAQS for each monitor in the HGB area is less than 1.0 days per year, 

and therefore, the area is attaining the one-hour ozone standard. On March 7, 2014, the TCEQ 

submitted to the EPA a certification evaluation and concurrence report for early certification of 

2013 ambient air monitoring data for ozone along with a request for a finding of attainment for 

the HGB area for the revoked one-hour ozone NAAQS. On May 30, 2014, the EPA verified that 

the 2013 ambient air monitoring data for ozone met all data quality requirements for attaining 

the one-hour ozone standard2. The HGB area continued to monitor attainment of the standard 

in 2014. As of August 4, 2015, the HGB area continues to monitor attainment of the one-hour 

ozone standard.

A one-hour ozone HGB RS demonstration was submitted to the EPA on July 22, 2014 in the 

form of a letter and attached report3

. The EPA Region 6 Administrator, Ron Curry, signed the 

proposed approval of the one-hour ozone HGB RS demonstration on July 29, 2015. Although 

the EPA’s 2008 ozone standard SIP requirements rule indicates that public notice and comment 

are not required, the commission adopted an HGB RS SIP revision for the one-hour ozone 

NAAQS (Non-Rule Project No. 2014-011-SIP-NR) on July 1, 2015.

SECTION 2: AIR QUALITY DATA

2.1 Monitoring Network and Reporting Requirements

The ambient air quality monitoring network provides data to verify continued attainment of the 

1997 eight-hour ozone National Ambient Air Quality Standard (NAAQS).

The Houston-Galveston-Brazoria (HGB) nonattainment area monitoring network in 2015

consists of 20 regulatory ambient air ozone monitors located in Brazoria, Galveston, Harris, and 

Montgomery Counties. The City of Houston operates seven of the monitors: Clinton 

(C403/C113/C304); Houston North Wayside (C405); Houston Monroe (C406); Lang (C408); 

Houston Croquet (C409); Houston Westhollow (C410); and Park Place (C416). The Texas 

Commission on Environmental Quality (TCEQ) operates the remaining 13 ozone monitors: 

Houston East (C1); Houston Aldine (C8/C108/C150); Channelview (C15/C115); Northwest 

Harris County (C26), Houston Deer Park #2 (C35/C139), Seabrook Friendship Park (C45); 

Houston Bayland Park (C53); Conroe Relocated (C78); Manvel Croix Park (C84); Lynchburg 

Ferry (C1015); Lake Jackson (C1016); Baytown Garth (C1017); and Galveston 99th Street 

(C1034).

The monitors are managed in accordance with 40 Code of Federal Regulations (CFR) Part 58 to 

verify the attainment status of the area. The TCEQ commits to keep operating an appropriate air 

monitoring network in the HGB area and will continue to work with the United States 

Environmental Protection Agency (EPA) through the air monitoring network review process, as 

required by 40 CFR Part 58, to determine: the adequacy of the ozone monitoring network; if 

 2 Mark Hansen, Acting Associate Director for Air Programs, EPA. Letter to Richard A. Hyde, Executive 

Director, TCEQ. 30 May 2014.

3 See TCEQ’s HGB: Latest Ozone Planning Activities Web page 

(http://www.tceq.state.tx.us/airquality/sip/hgb/hgb-latest-ozone).
Page 6

additional monitoring is needed; and when monitoring can be discontinued. Air monitoring 

data from these monitors will continue to be quality assured according to the requirements in 

the EPA’s regulations until the end of the maintenance period (2028), certified, and reported to 

the EPA on the schedule required by 40 CFR Part 58.

2.2 Ozone Data

This section provides an analysis of air quality observational data in the HGB area. While the 

1997 eight-hour ozone NAAQS is expressed as 0.08 parts per million (ppm), the familiar 

convention of expressing concentrations in parts per billion (ppb), as 84 ppb, is also used in this 

section. A design value of 84 ppb or less demonstrates attainment of the NAAQS. Data for ozone 

and nitrogen oxides (NOX) were retrieved from the EPA’s Air Quality System database, and 

volatile organic compounds (VOC) data were retrieved from TCEQ’s automated gas 

chromatograph (auto-GC) database. Analyses of ozone data from federal reference method 

monitors and federal equivalent method monitors, those used by the EPA to compare to the 

NAAQS, are included in this section.

2.3 Ozone Trend Analysis

Trends in ozone are used to demonstrate the substantial progress the HGB area has made in 

improving air quality. The trend in design values for the eight-hour ozone NAAQS in the HGB 

area is seen clearly in Figure 2-1: Eight-Hour Ozone Design Values for the HGB Area. Although 

the HGB area exceeded the 1997 eight-hour ozone NAAQS at of the end of 2013, the HGB area 

monitored a design value 4 ppb below the NAAQS of 0.08 ppm (or 84 ppb) in 2014. The design 

value for the eight-hour ozone standard is the truncated three-year average of the fourth highest 

value, given three years of complete data. A complete year of data must include at least three 

valid calendar quarters of data, a valid quarter must contain at least two months of valid data, a 

valid month must have at least 75% of days with valid data, and finally, a valid day must have at 

least 18 hours with valid one-hour ozone concentrations. The eight-hour ozone design value in 

the HGB area has decreased nearly 33% over the past 24 years, from a design value of 119 ppb in 

1990 to a design value of 80 ppb in 2014.
Page 7

Figure 2-1: Eight-Hour Ozone Design Values for the HGB Area

The design value of a metropolitan area is the maximum design value of all of the area’s 

regulatory monitors’ individual design values. Because ozone varies spatially, it is also prudent 

to investigate trends at all monitors in an area. Table 2-1: Eight-Hour Ozone Design Values by 

Monitor contains eight-hour ozone design values at all regulatory monitors in the HGB area 

from 2000 through 2014. More monitors than those listed in Table 2-1 operate in the HGB area, 

but the design values at those additional monitors are not appropriate for compliance 

determinations because the monitors’ data do not meet the EPA’s quality assurance criteria and 

cannot be used for regulatory purposes. Only one of the 21 monitors in the HGB area, Manvel 

Croix Park (C84), exceeded the 1997 eight-hour ozone standard in 2011 through 2013; it did not 

exceed the standard in 2014. The other 19 regulatory HGB area ozone monitors measured an 

average 2014 design value of 72 ppb, demonstrating that the area overall is well below 84 ppb.
Page 8

Table 2-1: Eight-Hour Ozone Design Values by Monitor

Site Name

200020012002200320042005200620072008200920102011201220132014

Manvel Croix 

Park C84 91 97 97 96 91 85 84 84 89 88 87 80

Houston East 

C1 102 103 101 100 95 87 83 78 80 76 76 81 82 80 72

Northwest 

Harris County 

C26 108 105 101 100 94 93 91 91 85 84 81 84 83 82 75

Houston 

Bayland Park 

C53 111 110 100 102 101 103 103 96 91 84 82 83 80 81 75

Houston 

Monroe C406 106 93 90 90 95 97 99 91 81 71 72 74 78 78 74

Seabrook 

Friendship 

Park C45 85 94 92 90 86 80 78 75 78 80 77 72

Galveston 

99th St C1034 77 78 80 74 72

Park Place 

C416 89 78 77 78 80 78 74

Houston 

Aldine 

C8/C108/C150 111 108 107 100 95 92 88 84 83 83 83 83 81 77 72

Houston 

Croquet C409 110 104 102 99 99 98 94 87 80 76 77 80 80 81 75

Houston 

Texas Avenue 

C411 88 89 88 84 78 76 75 74 77 78 77 70

Clinton 

C403/C113/C3

04 101 97 93 96 96 95 85 79 73 74 76 79 80 76 68

Houston 

North 

Wayside C405 105 98 89 86 85 82 78 76 75 72 71 75 77 75 69

Houston 

Regional 

Office C81 95 94 88 88 84 81 74 72 73 77

Channelview 

C15/C115 87 90 89 85 83 80 78 78 80 79 73 67
Page 9

Site Name

200020012002200320042005200620072008200920102011201220132014

Lynchburg 

Ferry C1015 96 89 82 76 77 70 66

Houston Deer 

Park 2 

C35/C139 112 108 103 102 101 100 96 93 87 81 81 83 84 79 72

Lang C408

96 91 83 78 79 79 80 77 76 75 76 78 78 79 72

Lake Jackson 

C1016 79 79 76 76 74 74 73 72 70 66

Houston 

Westhollow 

C410 102 104 95 87 87 89 96 92 89 79 75 74 78 79 76

Conroe 

Relocated C78 78 85 86 85 84 80 71 71 74 79 79 76

Galveston 

Airport 

C34/C109 108 98 89 89 91 87 83

Texas City C10

98 91 83 80

Clute C11

93 91 86 87

Conroe C65

91

Houston 

Crawford 

C407 100 81

Total Number 

of Regulatory 

Monitors

18 22 23 25 23 23 22 22 22 21 21 21 22 21 21

Figure 2-2: Eight-Hour Ozone Design Value Statistics for All Monitors in the HGB Area

displays the statistically summarized maximum, median, and minimum eight-hour ozone design 

values computed across all monitors in the HGB area as well as how these distributions changed 

over time. The eight-hour ozone design value exhibited a noticeable downward trend from 2000

until about 2003, and again after 2004. Before 2001, no monitors in the HGB area met the 1997 

eight-hour ozone NAAQS; since then, the area has seen a steady increase in the number of 

monitors attaining the standard. Since 2014, all monitors in the HGB area have been below the 

1997 eight-hour ozone NAAQS of 84 ppb.
Page 10

Figure 2-2: Eight-Hour Ozone Design Value Statistics for All Monitors in the HGB 

Area

Other useful information regarding ozone trends can also be obtained by examining the number 

of days where the daily eight-hour ozone maximum concentration was greater than 84 ppb in a 

year. This information is an important indicator of expected future ozone attainment in an area. 

The number of days over 84 ppb analysis demonstrates both that the area remains in current 

attainment, in addition to the distribution of exceedances over time, which provides evidence 

that existing control strategies for ozone are effective. Figure 2-3: Number of 1997 Eight-Hour 

Ozone Exceedance Days by Monitor in the HGB Area shows the number of days where the 

eight-hour ozone was greater than 84 ppb by year for each currently operating HGB monitor 

from 1990 through 2014. The number of days is the total number of unique days on which any 

monitor in the HGB area registered a daily peak eight-hour ozone concentration greater than 84 

ppb. In 2014, only one day had an eight-hour ozone concentration greater than 84 ppb. Since 

1990, the number of days with ozone concentrations above 84 ppb has decreased; a decrease 

that is especially pronounced from 1999 through 2002, then again from 2005 through 2008. 

The number of days with ozone concentrations above 84 ppb occurring in the HGB area fell 98%

from 56 days in 1990 to one day in 2014.
Page 11

Figure 2-3: Number of 1997 Eight-Hour Ozone Exceedance Days by Monitor in the 

HGB Area

2.4 Trend Analysis for Ozone Precursors

Decreases in NOX and VOC, precursors to ozone formation, demonstrate the effectiveness of 

control measures in reducing NOX and VOC emissions, generally support declining ozone 

values, and indicate that ozone emission reductions are due to NOX and VOC emission 

reductions in the eight-county HGB area; however, ozone may not always exhibit trends 

identical to its precursors due to other variables such as meteorological conditions. This section 

evaluates trends in concentrations of NOX and VOC. Only data that met data completeness 

checks are used in this section. To meet the completeness check, each day must contain at least 

18 valid hours of data, each month must contain at least 75% of days with data, each quarter 

must have at least two months of data, and each year must contain at least three quarters of 

data.

NOX emissions are a variable mixture of nitric oxide and nitrogen dioxide and are critical 

precursors to ozone formation. As NOX emissions decrease, ambient concentrations of these 

compounds should also decrease. NOX emissions are primarily created by fossil fuel 

combustion, lightning, biomass burning, and microbial action in soil.

Annual maxima, annual 90th percentile, and annual average daily peak one-hour NOX values 

observed in the HGB area are plotted in Figure 2-4: Annual Maxima, 90th Percentile and 

Average of Daily Peak NOx Values (ppb) in the HGB Area, 2000 through 2014. The figure uses 

a logarithmic scale so that all three statistics are visible, and a linear regression line was added 
Page 12

to each statistic. The linear regression line of the yearly maximum shows a negative slope of 20.5 

ppb per year with a correlation coefficient (r2) of 0.65, and the regression line of the yearly 90th 

percentile shows a negative slope of 3.6 ppb per year with an r2 of 0.80. The linear regression 

line of the yearly average shows a negative slope of 1.7 ppb per year with an r2 of 0.82. All three 

measures decreased markedly over the period from 2000 through 2014, falling 40% 

(maximum), 29% (90th percentile), and 27% (mean). Strong downward trends in ambient NOX

concentrations depicted in the emission-trend data are evidence of the effectiveness of emission 

controls implemented in the HGB area and would be expected to support declining ozone 

values, as observed in the HGB area.

Figure 2-4: Annual Maxima, 90th Percentile and Average of Daily Peak NOX Values 

(ppb) in the HGB Area, 2000 through 2014

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. This section focuses on two prevalent VOC compounds that are associated with 

rapid and efficient ozone formation, ethylene and propylene. Since the majority of the 

petrochemical industry with VOC production in the HGB area is located 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. A geometric mean was calculated 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 
Page 13

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, thus, the 

geometric mean was evaluated to provide an assessment of VOC emissions in the HGB area.

The annual geometric mean of ethylene concentrations in parts per billion carbon (ppbC) is 

shown in Figure 2-5: Yearly Geometric Mean Ethylene Concentrations (ppbC) at the Eight 

Houston Ship Channel Monitors, 2000 through 2014. 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. While 

trends are variable from year to year, generally, the geometric mean ethylene concentrations at 

all of the auto-GC monitors have decreased. Ethylene at the Channelview monitor (C15/C115) 

observed an increase from 2012 to 2013, then a decrease from 2013 to 2014. Concentrations at

50% of the monitoring sites studied (Clinton (C403/C113/C304), Houston Deer Park 2 

(C35/C139), Lynchburg Ferry (C1015) and Cesar Chavez (C1020) monitors) saw small increases 

from 2013 through 2014; however, the overall trend from 2000 through 2014 is decreasing.

Figure 2-5: Yearly Geometric Mean Ethylene Concentrations (ppbC) at the Eight 

Houston Ship Channel Monitors, 2000 through 2014

Figure 2-6: Yearly Geometric Mean Propylene Concentrations (ppbC) at the Eight Houston 

Ship Channel Monitors, 2000 through 2014 shows the annual geometric mean for propylene. 

Like ethylene, only three of the eight monitors had enough data to calculate annual geometric 

mean propylene prior to 2004. Note that the y-axis in this figure is the same as in Figure 2-5. 
Page 14

The geometric means for propylene are lower than the geometric means for ethylene for all the 

years. All monitors showed a steady decrease in geometric mean propylene from 2000 through 

2014, although three of the eight monitors, Clinton (C403/C113/C304), Lynchburg Ferry 

(C1015), and Houston Milby Park(C169) saw increases in 2014. Though decreasing at different 

rates, these long-term decreases in ambient concentrations of ethylene and propylene suggest 

overall industrial emissions of these compounds have decreased considerably since 2000.

Figure 2-6: Yearly Geometric Mean Propylene Concentrations (ppbC) at the Eight 

Houston Ship Channel Monitors, 2000 through 2014

2.5 Ozone Data Summary

Ozone concentrations have decreased nearly 33% in the HGB area from 1990 through 2014. In 

2014, the eight-hour ozone design value met the 1997 eight-hour ozone NAAQS of 0.08 ppm. 

Examination of the number of days where eight-hour ozone concentrations exceeded 0.08 ppm 

reveals substantial downward trends. Evaluation of local changes of ozone precursors showed 

similar significant downward trends. These results suggest that the significant ozone reductions 

achieved in the HGB area are primarily due to NOX and VOC emission reductions in the eightcounty HGB area, the emission reduction control strategies are effective, and that projections for 

future attainment status are well-founded.
Page 15

SECTION 3: PERMANENT AND ENFORCEABLE EMISSIONS REDUCTIONS

3.1 Control Measures

The Houston-Galveston-Brazoria (HGB) nonattainment area for the 1997 eight-hour ozone

National Ambient Air Quality Standard (NAAQS), which consists of Brazoria, Chambers, Fort 

Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties, includes some of the most 

comprehensively controlled industrial sources in the world. The Texas Commission on 

Environmental Quality (TCEQ) has developed stringent and innovative regulations that address 

nitrogen oxides (NOX), volatile organic compounds (VOC), and highly reactive volatile organic 

compounds (HRVOC).

3.2 List of Existing Control Measures

Over decades of air quality planning to improve ozone levels in the HGB area, a broad range of 

control measures have been implemented for each emission source category. Table 3-1: Existing 

Ozone Control Measures Applicable to the HGB Eight-County Nonattainment Area lists the 

existing ozone control strategies that have been implemented for the one-hour and 1997 eighthour ozone standards in the HGB area. The measures listed in Table 3-1 are permanent and 

enforceable and are included in the applicable implementation plan for the one-hour and 1997 

eight-hour ozone standards in accordance with Federal Clean Air Act (FCAA), §107(d)(3)(E)(iii).

Table 3-1: Existing Ozone Control Measures Applicable to the HGB Eight-County 

Nonattainment Area

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
Page 16

Measure Description Start Date(s)

Volatile Organic 

Compounds (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) 

and other state implementation plan (SIP)

planning purposes: general vent gas control, 

industrial wastewater, loading and unloading 

operations, general VOC LDAR, solvent using 

process, etc.

December 31, 2002 

and earlier

VOC Control Measures –

Offset Lithographic 

Printers

30 TAC Chapter 115, 

Subchapter E, Division 4

Revised to limit VOC content of solvents used by 

offset lithographic printing facilities and to 

include smaller sources in rule applicability (see 

Appendix D: Reasonably Available Control 

Technology Analysis of the Houston-GalvestonBrazoria Attainment Demonstration State 

Implementation Plan Revision for the 1997 EightHour Ozone Standard adopted March 10, 2010

(2010 HGB AD SIP Revision) for more details)

March 1, 2011 for 

major sources

March 1, 2012 for 

minor sources
Page 17

Measure Description Start Date(s)

VOC Control Measures –

Solvent-Using Processes

30 TAC Chapter 115, 

Subchapter E

Revised to implement RACT requirements per 

control technique guidelines published by the 

United States Environmental Protection Agency 

(EPA)

Seven emission source categories in the HoustonGalveston-Brazoria (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-GalvestonBrazoria 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

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 

approved by the EPA 

on March 17, 2014. 

Facilities may 

continue operating 

Stage II until August 

31, 2018
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Measure Description Start Date(s)

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, 

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

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
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Measure Description Start Date(s)

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

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 computer checks for 1996 and newer 

vehicles and dynamometer testing for pre-1996 

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 nonroad use to have an 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 non-road 

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 Houston-Galveston-Brazoria 

State Implementation Plan (With Detailed 

Strategies), prepared for H-GAC by ENVIRON 

International Corporation, of the 2010 HGB AD 

SIP Revision)

Phase in through 2018
Page 20

Measure Description Start Date(s)

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: Tiers 1, 2, and 3 vehicle standards, low 

sulfur diesel standards, National Low Emission 

Vehicle standards, and reformulated gasoline

Phase in through 2025

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

See Section 3.3.5

The following control measures being implemented in the HGB area are permanent and 

enforceable, but the emissions reductions from these control measures were not included in 

previous one-hour and 1997 eight-hour HGB attainment demonstration (AD) state 

implementation plan (SIP) revisions.

3.2.1 Highly Reactive Volatile Organic Compounds Emissions Cap and Trade Program

The Highly Reactive Volatile Organic Compounds Emission Cap and Trade (HECT) Program 

rules in 30 Texas Administrative Code (TAC) Chapter 101, Subchapter H, Division 6 established 

a mandatory annual HRVOC emission cap on sites in the HGB 1997 eight-hour ozone 

nonattainment area with the potential to emit greater than 10 tons per year (tpy) of HRVOC

from facilities subject to 30 TAC Chapter 115, Subchapter H, Division 1 or Division 2. These 

facilities include vent gas streams, flares, and cooling tower heat exchange systems. Sites in 

Harris County are required to participate in the HECT Program. The program was implemented 

on January 1, 2007.

The HECT Program cap is enforced by the allocation, trading, and banking of allowances. An 

allowance is the equivalent of one 1.0 ton of HRVOC emissions. The HECT Program cap was 

established at a level demonstrated as necessary to allow the HGB area to attain the one-hour 

ozone standard along with a 5% compliance margin to account for potential emissions 

variations. The total initial cap was 3,451.5 tpy.

Allowances allocated from 2007 through 2010 were based on historical levels of activity 

reported by affected sites. For 2011 and beyond, a site’s allocation was determined by 

multiplying the total HECT cap by an industry-sector factor and a site-specific factor. The 
Page 21

industry-sector factor was determined by grouping sites into sectors and determining each site’s 

proportion based on actual emissions. The site-specific factor was based on a site’s uncontrolled 

emissions as a proportion of the total uncontrolled emissions from all sites in that industry 

sector. The reallocation includes a mandatory 10% cap reduction implemented during 2014, 

with additional 5% reductions implemented at the start of each control period for 2015, 2016, 

and 2017. The final HECT Program cap is set at 2,588.6 tpy for 2017 and all subsequent control 

periods. Affected sites that do not receive an allocation of allowances must use allowances 

allocated to sites already participating in the program to cover annual HRVOC emissions.

3.2.2 Mass Emissions Cap and Trade Program

The Mass Emissions Cap and Trade (MECT) Program rules in 30 TAC Chapter 101, Subchapter 

H, Division 3 established a mandatory annual NOX emission cap on sites in the HGB 1997 eighthour ozone nonattainment area that are either a major source of NOX with facilities subject to 

the NOX emissions specifications in 30 TAC §117.310 or §117.1210, or have an uncontrolled 

design capacity to emit at least 10 tpy of NOX from facilities subject to 30 TAC §117.2010. 

Affected facilities include: utility boilers, auxiliary steam boilers, or stationary gas turbines; 

industrial, commercial, or institutional boilers and process heaters; stationary gas turbines; 

stationary internal combustion engines; fluid catalytic cracking units (including carbon 

monoxide boilers, carbon monoxide furnaces, and catalyst regenerator vents); boilers and 

industrial furnaces that were regulated as existing facilities by the United States Environmental 

Protection Agency (EPA) under 40 Code of Federal Regulations (CFR) Part 266, Subpart H (as 

in effect on June 9, 1993); duct burners used in turbine exhaust ducts; pulping liquor recovery 

furnaces; lime kilns; lightweight aggregate kilns; heat treating furnaces and reheat furnaces; 

magnesium chloride fluidized bed dryers; and incinerators.

The MECT Program cap is enforced by the allocation, trading, and banking of allowances. An 

allowance is the equivalent of 1.0 ton of NOX emissions. The MECT Program cap was 

implemented on January 1, 2002 at historical emission levels with mandatory NOX reductions 

increasing over time until achieving the final cap on April 1, 2007. Affected facilities that do not 

meet the criteria for receiving an allocation of allowances must use allowances allocated to 

facilities already participating in the program to cover annual NOX emissions.

The photochemical modeling for the Houston-Galveston-Brazoria Attainment Demonstration 

State Implementation Plan Revision for the 1997 Eight-Hour Ozone Standard adopted March 

10, 2010 (2010 HGB AD SIP Revision) included 120.0 tons per day (tpd) of NOX emissions in 

2018 based on the October 2009 MECT cap. The modeled MECT cap is a function of the actual 

allowance allocations, allowable allowance allocations, and the conversion of emission reduction 

credits to allowance allocations. The projected 2018 MECT cap, as of May 2015 is 109.6 tpd of 

NOX emissions, which is a reduction of 10.4 tpd of NOX emissions from the modeled MECT cap. 

This reduction can be attributed to facilities revising allowance allocations based on permit 

limits to allocations based on actual operating data since typically most facilities operate below 

their permit limits. Further MECT cap reductions are expected in the future due to sources that 

have yet to convert their allowable allowances into actual allowances.

3.2.3 Tier 3 Motor Vehicle Emission and Gasoline Sulfur Fuel Standards

On April 28, 2014, the EPA finalized the Control of Air Pollution from Motor Vehicles: Tier 3 

Motor Vehicle Emission and Fuel Standards (79 FR 23413). Starting in 2017, Tier 3 sets new 

vehicle emissions standards and lowers the sulfur content of gasoline, considering the vehicle 

and its fuel as an integrated system.
Page 22

Tier 3 motor vehicle emission standards will reduce both tailpipe and evaporative emissions 

from passenger cars, light-duty trucks, medium-duty passenger vehicles, and some heavy-duty 

vehicles beginning model year 2017 and will be fully phased in by model year 2025. The Tier 3 

motor vehicle emission standards also extend the regulatory useful life period during which the 

standards apply from 120,000 miles to 150,000 miles.

When fully implemented, the Tier 3 motor vehicle exhaust emission standards for light-duty 

vehicles will provide approximately an 80% reduction in non-methane organic gases (NMOG) 

and NOX (NMOG+NOX) standards and a 70% reduction in per-vehicle particulate matter (PM) 

standards when compared to the current fleet average. The Tier 3 motor vehicle exhaust 

standards for heavy-duty vehicles provide about a 60% reduction in both fleet average 

NMOG+NOX vehicle emissions standards and per-vehicle PM standards when compared to the 

current vehicle emissions standards.

The Tier 3 gasoline sulfur standards will limit gasoline sulfur to no more than 10 parts per 

million (ppm) of sulfur on an annual average basis beginning January 1, 2017, a reduction of 

approximately 66% when compared to the current standard. The current gasoline sulfur 

standards specifying an 80 ppm refinery gate cap and 95 ppm downstream cap are maintained 

under the new Tier 3 gasoline sulfur standards. Removing sulfur from gasoline allows a vehicle’s 

catalyst to work more efficiently. The Tier 3 fuel standards will make emission control systems 

more effective for both existing and new vehicles, and will enable automobile manufacturers to 

meet the Tier 3 motor vehicle emissions standards.

3.2.4 New International Marine Diesel Engine and Marine Fuel Standards for Oceangoing 

Vessels and Emissions Control Areas

In March 2009, the United States (U.S.) government submitted a request to the International 

Maritime Organization (IMO) for the creation of an emissions control area (ECA) around the 

nation's coastlines. The request was granted and the North American ECA was officially 

designated by the IMO on March 26, 2010 and became enforceable in August 2012. All marine 

diesel fuels used by oceangoing vessels (OGV) in the North American ECA will be limited to a 

maximum sulfur content of 1,000 ppm beginning January 1, 2015, and all new engines on OGV 

operating in these areas must use emission controls that achieve an 80% reduction in NOX 

emissions beginning January 1, 2016.

The EPA regulations for marine diesel fuel and new marine engines less than 30 liters per 

cylinder displacement and the new International Convention for the Prevention of Pollution 

from Ships (MARPOL) Annex VI standards for marine residual fuels and new marine diesel 

engines above 30 liters per cylinder displacement will apply to all OGV flagged and registered in 

the U.S. The EPA's regulations for new Category 3 marine engines and new sulfur limits for 

marine diesel fuel will also apply to all OGV flagged and registered in the U.S. In addition, the 

new MARPOL Annex VI standards will apply to all new marine diesel engines and fuels on 

foreign marine vessels that operate near U.S. coasts and ports.

The new marine diesel engine and fuel standards will provide a 96% reduction in sulfur in 

marine diesel fuels, as well as an 85% reduction in PM emissions and an 80% reduction in NOX

emissions, when compared to current standards4

.

 4 EPA, 2009. Oceangoing Vessels, Emission Control Area Designation, 

http://www.epa.gov/otaq/oceanvessels.htm#emissioncontrol, Office of Transportation and Air Quality.
Page 23

Cumulatively, these new marine diesel engine and fuel standards are estimated by the EPA to 

result in a 0.5 to 1.0 parts per billion reduction of ozone in the ambient air of the HGB ozone 

nonattainment area by 20205

.

3.3 Additional Measures

Additional air quality improvement measures being implemented in the HGB area are described 

in this section. These additional measures are beneficial toward reducing ozone and assure that 

the HGB area will continue to maintain the 1997 eight-hour ozone standard.

3.3.1 SmartWay Transport Partnership and the Blue Skyways Collaborative

Among its various efforts to improve air quality in Texas, the TCEQ continues to promote two 

voluntary programs in cooperation with the EPA: SmartWay Transport Partnership and Blue 

Skyways Collaborative.

The SmartWay Transport Partnership is a market-driven partnership aimed at helping 

businesses move goods in the cleanest most efficient way possible. This is a voluntary EPA 

program primarily for the freight transport industry that promotes strategies and technologies 

to help improve fleet efficiency while also reducing air emissions.

There are over 3,000 SmartWay partners in the U.S., including most of the nation’s largest truck 

carriers, all the Class 1 rail companies, and many of the top Fortune 500 companies. Since its 

founding, SmartWay has reduced oil consumption by 120.7 million barrels and prevented the 

release of 738,000 tons of NOX and 37,000 tons of PM into the atmosphere6

. Ports in the U.S. 

rely on SmartWay’s Port Drayage Truck program to help reduce pollution in and around major 

national ports. The Port of Houston Authority’s (PHA) partnership with the Environmental 

Defense Fund and the Houston-Galveston Area Council (H-GAC) in the Port Drayage Truck 

Bridge Loan Program received $9 million from the EPA’s Diesel Emissions Reduction Act 

(DERA) SmartWay Program in 2009. On average, four trucks a month, or about 50 trucks a 

year, were approved for replacement funding.

In April 2015, the EPA awarded the PHA with a DERA grant of nearly $900,000. This newest 

grant, which will have matching funds of $1,680,142, will have a total commitment of more than 

$2.5 million. A total of 25 drayage trucks will replace trucks operating in the Port of Houston. 

The latest funding will provide for new trucks powered by certified engines that are model year 

2011 or newer, which are estimated to be 90% cleaner. These drayage trucks operate in the Port 

of Houston and along the Houston Ship Channel. The new trucks will also have Global 

Positioning System units to collect data on idling and port operations, which will allow fleet 

owners and operators to gauge opportunities for additional fuel savings and emissions 

reduction7

.

Approximately 170 Texas companies are SmartWay partners. The SmartWay Transport 

Partnership will continue to benefit the HGB area by reducing emissions as more companies and 

 5 EPA, 2009. Regulatory Announcement: Proposal of Emission Control Area Designation for Geographic 

Control of Emissions from Ships, EPA-420-F-09-015, Figure 4: Potential Benefits of U.S. ECA Ozone 

Reductions in 2020, March 2009.

6 EPA, 2014. SmartWay Program Highlights 2014, EPA-420-F-14-003, February 2014.

http://www.epa.gov/smartway/about/documents/basics/420f14003.pdf

7 http://www.portofhouston.com/inside-the-port-authority/communications/business-news/epaadministrator-visits-port-of-houston-authority-to-make-formal-announcement/
Page 24

affiliates join, and additional idle reduction, trailer aerodynamic kits, low-rolling resistance tire, 

and retrofit technologies are incorporated into SmartWay-verified technologies.

The Blue Skyways Collaborative was created to encourage voluntary air emission reductions by 

planning or implementing projects that use innovations in diesel engines, alternative fuels, and 

renewable energy technologies applicable to on-road and non-road sources. The Blue Skyways 

Collaborative partnerships include international, federal, state, and local governments, nonprofit organizations, environmental groups, and private industries.

3.3.2 American Waterways Operators Tank Barge Emissions Best Management Practices

Using infrared gas imaging technology in field studies conducted in the summer of 2005, the 

TCEQ detected inadvertent VOC emissions from tank barges operating in the HGB area. The 

Louisiana Department of Environmental Quality (LDEQ) also detected inadvertent emissions 

from tank barges in similar field studies conducted in the same time period. In response to these 

field studies, the American Waterways Operators (AWO) voluntarily developed industry best 

management practices (BMP) to reduce VOC emissions from tank barges. The BMP include 

procedures to reduce VOC emissions from equipment and operations on tank barges. The 

recommendations are a combination of inspection, corrective action, preventative maintenance, 

and operational, procedural, and training practices.

The BMP were reviewed by the Chemical Transportation Advisory Committee, United States 

Coast Guard, LDEQ, and TCEQ. The BMP document was distributed to AWO members in 2006 

for implementation on a voluntary basis. While the BMP are voluntary measures and do not 

impose an enforceable commitment on AWO members, the implementation of the BMP, where 

applicable, may contribute to reducing inadvertent VOC emissions from barges during dock 

operations and during transit, which will help improve air quality in the HGB area. A copy of the 

2006 BMP document is provided in the 2010 HGB AD SIP Revision as Appendix 

J: Recommendations for Best Management Practices to Control and Reduce Inadvertent 

Cargo Vapor Emissions in the Tank Barge Community.

3.3.3 Consent Decrees with Refineries

The EPA's National Petroleum Refinery Initiative8 has resulted in multi-issue settlement 

agreements with the nation's major petroleum refineries. As of May 2014, 109 refineries

representing more than 90% of total domestic refining capacity are under settlement, and 

negotiations are underway with other refiners not currently under settlement. The EPA consent 

decrees limit emissions from fluidized catalytic cracking units, sulfur recovery units, heaters and 

boilers, and flares. The EPA estimates that full implementation of the current settlements will 

result in more than 93,000 tpy of NOX emission reductions. The EPA also anticipates VOC 

emission reductions will result from consent decree requirements that reduce hydrocarbon 

flaring including:

• installing continuous emissions monitoring systems (CEMS) or predictive emissions 

monitoring systems;

• operating a flare gas recovery system to control continuous or routine flaring;

• limiting flaring to only process upset gases, fuel gas released as a result of relief valve 

leakage, or gas released due to a malfunction; and

• eliminating the routes of generated fuel gases and monitoring the flare with CEMS or a flow 

meter.

 8 http://www2.epa.gov/enforcement/petroleum-refinery-national-case-results
Page 25

Although some of the estimated NOX and VOC emission reductions may have occurred prior to 

2006, full implementation of the settlements is not expected until the end of 2015. Since 

approximately 14% of the nation’s petrochemical refining capacity is located in the HGB area9

, 

the commission expects the HGB area will benefit from the NOX and VOC emission reductions

required by these settlements.

3.3.4 Standards of Performance for Stationary Compression Ignition Internal Combustion 

Engines

The TCEQ previously adopted NOX emission standards for stationary diesel reciprocating 

internal combustion engines in 30 TAC Chapter 117 for the HGB area. The NOX emission 

standards for stationary diesel engines in §117.310 and §117.2010 are used in conjunction with 

the MECT Program for sources subject to MECT. For sources subject to §117.2010 that are not in 

MECT, the NOX emission standards apply on a unit-by-unit basis. Additionally, the TCEQ 

adopted requirements in the exemption criteria for stationary diesel reciprocating internal 

combustion engines in §117.303 and §117.2003 that require engines installed, modified, 

reconstructed, or relocated on or after October 1, 2001 to meet the corresponding emission 

standards for non-road engines in 40 CFR Part 89, §89.112(a), Table 1: Emission Standards to 

be in effect at the time of the installation, modification, reconstruction, or relocation of the 

engine.

The combination of the emission standards, the MECT Program, and the provisions to meet the 

EPA’s Tier standards (Tiers 1, 2, and 3) in 40 CFR Part 89 to qualify for exemption makes the 

Chapter 117 requirements for stationary diesel reciprocating internal combustion engines 

equivalent to, or more stringent than, most of the requirements in the EPA’s New Source 

Performance Standards in 40 CFR Part 60, Subpart IIII, Standards of Performance for 

Stationary Compression Ignition Internal Combustion Engines. However, the NOX emission 

standards in 40 CFR §60.4204(c)(3) for large-cylinder non-emergency stationary compression 

ignition internal combustion engines (i.e., diesel-fired engines) installed on or after January 1, 

2016 are more stringent than the lowest NOX emission standards for stationary diesel 

reciprocating internal combustion engines in §117.310 and §117.2010 and 40 CFR Part 

§89.112(a), Table 1.

The exact amount of NOX reductions resulting from 40 CFR §60.4204(c)(3) will be dependent 

on the turnover of existing engines and new installations after 2015 and cannot be estimated at 

this time. However, the requirements for new non-emergency stationary diesel-fired engines in 

the large-cylinder category starting in 2016 should ultimately result in additional NOX

reductions beyond that already relied upon in the 2010 HGB AD SIP Revision.

3.3.5 Energy Efficiency and Renewable Energy Measures

Energy efficiency (EE) measures are typically programs that reduce the amount of electricity 

and natural gas consumed by residential, commercial, industrial, and municipal energy 

consumers. Examples of EE measures include increasing insulation in homes, installing 

compact fluorescent light bulbs, and replacing motors and pumps with high efficiency units. 

Renewable energy (RE) measures include programs that generate energy from resources that 

are replenished or are otherwise not consumed as with traditional fuel-based energy production. 

Examples of RE include wind energy and solar energy projects.

 9 U.S. Energy Information Administration. Refinery Capacity Report. June 21, 2013. 

http://www.eia.gov/petroleum/refinerycapacity/
Page 26

Texas leads the nation in RE generation from wind. As of December 2014, Texas has 14,098 

megawatts (MW) of installed wind generation capacity10; more than double that of California, 

the state with the next highest amount of installed wind generation capacity. Texas’ total net 

electrical generation from renewable wind generators for 2014 is estimated to be approximately 

39 million megawatt-hours (MWh)11, approximately 22% of the total wind net electrical 

generation for the U.S.

While EE/RE measures are beneficial and can result in lower overall emissions from fossil fuelfired power plants in Texas, emission reductions resulting from these programs are not 

explicitly included in the photochemical modeling for SIP purposes because local efficiency 

efforts may not result in local emissions reductions or may be offset by increased demand in 

electricity. The complex nature of the electrical grid makes accurately quantifying emission 

reductions from EE/RE measures difficult. At any given time, it is impossible to determine 

exactly where a specific user’s electricity was produced. The electricity for users in a 

nonattainment may not necessarily be generated solely within that nonattainment area. For 

example, some of the electricity used within a nonattainment area in East Texas could be 

generated by a power plant in a nearby attainment county or even in West Texas. If electrical 

demand is reduced in a nonattainment area due to local efficiency measures, the resulting 

emission reductions from power generation facilities may occur in any number of locations 

around the state. Similarly, increased RE generation may not necessarily replace electrical 

generation from local fossil fuel-fired power plants within a particular nonattainment area.

The Texas Legislature has enacted a number of EE/RE measures and programs. The following is 

a summary of Texas EE/RE legislation since 1999.

• 76th Texas Legislature, 1999

o Senate Bill (SB) 7

o House Bill (HB) 2492

o HB 2960

• 77th Texas Legislature, 2001

o SB 5

o HB 2277

o HB 2278

o HB 2845

• 78th Texas Legislature, 2003

o HB1365 (Regular Session)

• 79th Texas Legislature, 2005

o SB 20 (1st Called Session)

o HB 2129 (Regular Session)

o HB 2481 (Regular Session)

• 80th Texas Legislature, 2007

o SB 12

o HB 66

o HB 3070

o HB 3693

 10 U.S. Department of Energy, National Renewable Energy Laboratory, 

http://apps2.eere.energy.gov/wind/windexchange/wind_installed_capacity.asp

11 U.S. Department of Energy, Energy Information Administration, Form EIA-923 data, 

http://www.eia.gov/electricity/data/eia923/
Page 27

• 81st Texas Legislature, 2009

o None

• 82nd Texas Legislature, 2011

o SB 898 (Regular Session)

o SB 924 (Regular Session)

o SB 981 (Regular Session)

o SB 1125 (Regular Session)

o SB 1150 (Regular Session)

o HB 51 (Regular Session)

o HB 362 (Regular Session)

• 83rd Texas Legislature, 2013

o None

• 84th Texas Legislature, 2015

o SB 1626

o HB 1736

3.3.5.1 Renewable Energy

SB 5, 77th Texas Legislature, 2001, set goals for political subdivisions in affected counties to 

implement measures to reduce energy consumption from existing facilities by 5% each year for 

five years from January 1, 2002 through January 1, 2006. In 2007, the 80th Texas Legislature 

passed SB 12, which extended the timeline set in SB 5 through 2007 and made the annual 5%

reduction a goal instead of a requirement. The State Energy Conservation Office (SECO) is 

charged with tracking the implementation of SB 5 and SB 12. Also during the 77th Texas 

Legislature, the Energy Systems Laboratory (ESL), part of the Texas Engineering Experiment 

Station, Texas A&M University System, was mandated to provide an annual report on EE/RE 

efforts in the state as part of the Texas Emissions Reduction Plan (TERP) under Texas Health 

and Safety Code (THSC), §388.003(e).

The 79th Texas Legislature, 2005, Regular and 1st Called Sessions, amended SB 5 through SB 

20, HB 2129, and HB 2481 to add, among other initiatives, renewable energy initiatives that 

require: 5,880 MW of generating capacity from renewable energy by 2015; the TCEQ to develop 

a methodology for calculating emission reductions from renewable energy initiatives and 

associated credits; the ESL to assist the TCEQ in quantifying emissions reductions from EE/RE 

programs; and the Public Utility Commission of Texas (PUCT) to establish a target of 10,000 

MW of installed renewable technologies by 2025. Wind power producers in Texas exceeded the 

renewable energy generation target by installing over 10,000 MW of wind electric generating 

capacity by 2010.

HB 2129, 79th Texas Legislature, 2005, Regular Session, directed the ESL to collaborate with

the TCEQ to develop a methodology for computing emission reductions attributable to use of 

renewable energy and for the ESL to annually quantify such emission reductions. HB 2129 

directed the Texas Environmental Research Consortium to use the Texas Engineering 

Experiment Station to develop this methodology. With the TCEQ’s guidance, the ESL produces 

an annual report, Statewide Air Emissions Calculations from Energy Efficiency, Wind and 

Renewables, detailing these efforts.

In addition to the programs discussed and analyzed in the ESL report, local governments may 

have enacted measures beyond what has been reported to SECO and the PUCT. The TCEQ 

encourages local political subdivisions to promote EE/RE measures in their respective 

communities and to ensure these measures are fully reported to SECO and the PUCT.
Page 28

SB 981, 82nd Texas Legislature, 2011, Regular Session, allows a retail electric customer to 

contract with a third party to finance, install, or maintain a distributed renewable generation 

system on the customer's side of the electric meter, regardless of whether the customer owns the 

installed system. SB 981 also prohibits the PUCT from requiring registration of the system as an 

electric utility if the system is not projected to send power to the grid.

HB 362, 82nd Texas Legislature, 2011, Regular Session, helps property owners install solar 

energy devices such as electric generating solar panels by establishing requirements for property 

owners associations’ approval of installation of solar energy devices. HB 362 specifies the 

conditions that property owners associations may and may not deny approval of installing solar 

energy devices.

SB 1626, 84th Texas Legislature, 2015, modified the provisions established by HB 362 from the 

82nd Texas Legislature, 2011, Regular Session, regarding property owners associations’ 

authority to approve and deny installations of solar energy devices such as electric generating 

solar panels. HB 362 included an exception that allowed developers to prohibit installation of 

solar energy devices during the development period. SB 1626 limits the exception during the 

development period to developments with 50 or fewer units.

3.3.5.2 Residential and Commercial Building Codes and Programs

THSC, Chapter 388, Texas Building Energy Performance Standards, as adopted in SB 5 of the 

77th Texas Legislature, 2001, states in §388.003(a) that single-family residential construction 

must meet the energy efficiency performance standards established in the energy efficiency 

chapter of the International Residential Code. The Furnace Pilot Light Program includes energy 

savings accomplished by retrofitting existing furnaces. Also included is a January 2006 federal 

mandate raising the minimum Seasonal Energy Efficiency Ratio for air conditioners in singlefamily and multi-family buildings from 10 to 13.

THSC, Chapter 388, as adopted in SB 5 of the 77th Texas Legislature, 2001, states in 

§388.003(b) that non-single-family residential, commercial, and industrial construction must 

meet the energy efficiency performance standards established in the energy efficiency chapter of 

the International Energy Conservation Code.

HB 51, 82nd Legislature, 2011, Regular Session, requires municipalities to report 

implementation of residential and commercial building codes to SECO.

HB 1736, 84th Texas Legislature, 2015, updated THSC, §388.003 to adopt, effective September 

1, 2016, the energy efficiency chapter of the International Residential Code as it existed on May 

1, 2015. HB 1736 also established a schedule by which SECO could adopt updated editions of the 

International Residential Code in the future, not more often than once every six years.

3.3.5.3 Federal Facility Energy Efficiency and Renewable Energy Projects

Federal facilities are required to reduce energy use by Presidential Executive Order 13123 and 

the Energy Policy Act of 2005 (Public Law 109-58 EPACT20065). The ESL compiled energy 

reductions data for the federal EE/RE projects in Texas.

3.3.5.4 Political Subdivisions Projects

SECO funds loans for energy efficiency projects for state agencies, institutions of higher 

education, school districts, county hospitals, and local governments. Political subdivisions in 

nonattainment and affected counties are required by SB 5, 77th Texas Legislature, 2001, to 

report EE/RE projects to SECO. These projects are typically building systems retrofits, non-
Page 29

building lighting projects, and other mechanical and electrical systems retrofits such as 

municipal water and waste water treatment systems.

3.3.5.5 Electric Utility Sponsored Programs

Utilities are required by SB 7, 76th Texas Legislature, 1999, and SB 5, 77th Texas Legislature, 

2001, to report demand-reducing energy efficiency projects to the PUCT (see THSC, §386.205 

and Texas Utilities Code (TUC), §39.905). These projects are typically air conditioner 

replacements, ventilation duct tightening, and commercial and industrial equipment 

replacement.

SB 1125, 82nd Texas Legislature, 2011, Regular Session, amended the TUC, §39.905 to require 

energy efficiency goals to be at least 30% of annual growth beginning in 2013. The metric for the 

energy efficiency goal remains at 0.4% of peak summer demand when a utility program accrues 

that amount of energy efficiency. SB 1150, 82nd Texas Legislature, 2011, extended the energy 

efficiency goal requirements to utilities outside the Electric Reliability Council of Texas area.

3.3.5.6 State Energy Efficiency Programs

HB 3693, 80th Texas Legislature, 2007, amended the Texas Education Code, Texas Government 

Code, THSC, and TUC. The bill:

• requires state agencies, universities, and local governments to adopt energy efficiency 

programs;

• provides additional incentives for electric utilities to expand energy conservation and 

efficiency programs;

• includes municipal-owned utilities and cooperatives in efficiency programs;

• increases incentives and provides consumer education to improve efficiency programs; and

• supports other programs such as revision of building codes and research into alternative 

technology and renewable energy.

HB 51, 82nd Texas Legislature, 2011, Regular Session, requires new state buildings and major 

renovations to be constructed to achieve certification under an approved high-performance 

design evaluation system. HB 51 also requires, if practical, that certain new and renovated statefunded university buildings comply with approved high-performance building standards.

SB 898, 82nd Texas Legislature, 2011, Regular Session, extended the existing requirement for 

state agencies, state-funded universities, local governments, and school districts to adopt energy 

efficiency programs with a goal of reducing energy consumption by at least 5% per state fiscal 

year (FY) for 10 state FYs from September 1, 2011 through August 31, 2021.

SB 924, 82nd Texas Legislature, 2011, Regular Session, requires all municipally owned utilities 

and electric cooperatives that had retail sales of more than 500,000 MWh in 2005 to report 

each year to SECO information regarding the combined effects of the energy efficiency activities 

of the utility from the previous calendar year, including the utility's annual goals, programs 

enacted to achieve those goals, and any achieved energy demand or savings goals.

3.3.6 Clean Air Interstate Rule and Cross-State Air Pollution Rule

In March 2005, the EPA issued the Clean Air Interstate Rule (CAIR) to address electric 

generating unit (EGU) emissions that transport from one state to another. The rule incorporated

the use of three cap and trade programs to reduce sulfur dioxide (SO2) and NOX: the ozoneseason NOX trading program, the annual NOX trading program, and the annual SO2 trading 

program.
Page 30

For CAIR, Texas was not included in the ozone season NOX program but was included for the 

annual NOX and SO2 programs. As such, Texas was required to make necessary reductions in 

annual SO2 and NOX emissions from new and existing EGUs to demonstrate that emissions 

from Texas do not contribute to nonattainment or interfere with maintenance of the 1997 

particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 

micrometers (PM2.5) NAAQS in another state. CAIR consisted of two phases for implementing 

necessary NOX and SO2 reductions. Phase I addressed required reductions from 2009 through 

2014. Phase II was intended to address reductions in 2015 and thereafter.

In July 2006, the commission adopted a SIP revision to address how the state would meet 

emissions allowance allocation budgets for NOX and SO2 established by the EPA to meet the 

federal obligations under CAIR. The commission adopted a second CAIR-related SIP revision in 

February 2010. This revision incorporated various federal rule revisions that the EPA had 

promulgated since the TCEQ’s initial submittal. It also incorporated revisions to 30 TAC 

Chapter 101 resulting from legislation during the 80th Texas Legislature, 2007.

A December 2008 court decision found flaws in CAIR but kept CAIR requirements in place 

temporarily while directing the EPA to issue a replacement rule. In July 2011, the EPA finalized 

the Cross-State Air Pollution Rule (CSAPR) to meet FCAA requirements and respond to the 

court’s order to issue a replacement program. Texas was included in CSAPR for ozone season 

NOX, annual NOX, and annual SO2 due to the EPA’s determination that Texas significantly 

contributes to nonattainment or interferes with maintenance of the 1997 eight-hour ozone 

NAAQS and the 1997 PM2.5 NAAQS in other states. As a result of numerous EGU emission 

reduction strategies already in place in Texas, the annual and ozone season NOX reduction 

requirements from CSAPR were relatively small but still significant. CSAPR required an 

approximate 7% reduction in annual NOX emissions and less than 5% reduction in ozone season 

NOX emissions.

On August 21, 2012, the U.S. Court of Appeals for the District of Columbia (D.C.) Circuit vacated 

CSAPR. Under the D.C. Circuit Court’s ruling, CAIR would remain in place until the EPA 

develops a valid replacement. On October 5, 2012, the EPA filed a petition seeking an en banc

rehearing of the U.S. Court of Appeals’ decision regarding CSAPR, but the appeal was denied.

The EPA and various environmental groups petitioned the Supreme Court of the United States 

to review the D.C. Circuit Court's decision on CSAPR. On June 24, 2013, the Supreme Court 

granted the petitions and heard oral arguments on December 10, 2013. On April 29, 2014, a 

decision by the Supreme Court reversed the D.C. Circuit Court’s decision and remanded the 

case. On June 26, 2014, the EPA filed a motion with the U.S. Court of Appeals for the D.C. 

Circuit to lift the stay of CSAPR, which was granted on October 23, 2014. On November 21, 

2014, the EPA issued rulemaking that shifted the effective dates of CSAPR requirements to 

account for the time that had passed after the rule was stayed in 2011. As a result, the EPA is 

implementing the CSAPR federal implementation plan for Texas. Phase 1 of CSAPR took effect 

January 1, 2015 and Phase 2 is scheduled to begin January 1, 2017. Oral arguments on the 

remanded case were held on February 25, 2015. On July 28, 2015, the D.C. Circuit Court ruled 

that the 2014 annual SO2 budgets and the 2014 ozone season NOX budgets for Texas were 

invalid because they required overcontrol of Texas emissions, and remanded these budgets back 

to the EPA without vacatur.

3.3.7 Clean School Bus Program

HB 3469, 79th Texas Legislature, 2005, Regular Session, established the Clean School Bus 

Program, which provides monetary incentives for school districts in the state for reducing 
Page 31

emissions of diesel exhaust from school buses. As of May 2015, the TCEQ Clean School Bus 

Program has reimbursed approximately $28.5 million in grants for over 7,200 school buses 

across the state, with $6.9 million being used for 2,535 school buses in the HGB area.

3.3.8 Texas Emission Reduction Plan

The TERP program was created in 2001 by the 77th Texas Legislature to provide grants to offset 

the incremental costs associated with reducing NOX emissions from high-emitting heavy-duty 

internal combustion engines on heavy-duty vehicles, non-road equipment, marine vessels, 

locomotives, and some stationary equipment.

The primary emissions reduction incentives are awarded under the Diesel Emissions Reduction 

Incentive Program (DERI). DERI incentives are awarded to projects to replace, repower, or 

retrofit eligible vehicles and equipment to achieve NOX emission reductions in Texas ozone 

nonattainment areas and other counties identified as affected counties under the TERP program

where ground-level ozone is a concern.

From 2001 through August 2014, $905 million in DERI grants were awarded for projects 

estimated to help reduce 160,836 tons of NOX. Over $380 million in DERI grants were awarded 

to projects in the HGB area, with a projected 71,211 tons of NOX reduced. These projects were

estimated to reduce up to 20.5 tpd of NOX in the HGB area in 2015. This estimate will change 

yearly as older project reach the end of the project life and new projects begin achieving 

emissions reductions. Also, of the $380 million awarded in the HGB area, $11 million were 

awarded to H-GAC through third-party grants to administer subgrants in the HGB area. H-GAC 

has used this funding to target the replacement of drayage trucks operating in and from the Port 

of Houston with newer models with lower emission ratings.

The latest DERI Emissions Reduction Incentive Grants program grant round closed December 

16, 2014. Over $188 million in applications were received. The grant selections totaled 393 

projects for $63.8 million. Final grant awards and contracting will be completed by August 2015. 

Subject to final contracting, these projects are estimated to reduce 8,547 tons of NOX, including 

4,075 tons in the HGB area. This represents an additional 1.65 tpd of NOX reduced in the HGB 

area beginning in 2017. An additional $10 million will be awarded under the DERI Rebate 

Grants program, with contracts completed by August 2015.

Three other incentive programs under the TERP program will result in the reduction in NOX

emissions in the HGB area.

The Drayage Truck Incentive Program (DTIP) was established in 2013 to provide grants for the 

replacement of drayage trucks operating in and from seaports and rail yards located in 

nonattainment areas. The program has awarded grants to nine projects totaling $3.95 million. 

These projects are estimated to reduce 233 tons of NOX, including 208 tons in the HGB area. 

This represents an additional 0.17 tpd of NOX projected to be reduced in the HGB area 

beginning in 2017.

The Texas Clean Fleet Program (TCFP) was established in 2009 to provide grants for the 

replacement of light-duty and heavy-duty diesel vehicles with vehicles powered by alternative 

fuels, including: natural gas, liquefied petroleum gas, hydrogen, methanol (85% by volume), or 

electricity. This program is for larger fleets. Applicants must commit to replacing at least 20 

eligible diesel-powered vehicles with qualifying alternative fuel or hybrid vehicles over a 12-

month period. From 2009 through August 2014, almost $23.6 million in TCFP grants were 

awarded for projects to help reduce a projected 314.5 tons of NOX. Almost $6.8 million in TCFP 
Page 32

grants were awarded to projects in the HGB area, with a projected 61.9 tons of NOX reduced. 

The latest TCFP grant application period ended October 3, 2014, with five projects totaling 

$8.85 million selected for funding. These projects are estimated to result in 124 tons of NOX

reduced, including 30 tons in the HGB area. This represents an additional 0.024 tpd of NOX

projected to be reduced in the HGB area beginning in 2017.

The Texas Natural Gas Vehicle Grant Program (TNGVGP) was established in 2011 to provide 

grants for the replacement of medium-duty and heavy-duty diesel vehicles with vehicles 

powered by natural gas. This program may include grants for individual vehicles or multiple 

vehicles. The majority of the vehicle’s operation must occur in the Texas nonattainment areas, 

other counties designated as affected counties under the TERP, and the counties in and between 

the triangular area between Houston, San Antonio, and Dallas-Fort Worth. From 2011 through 

August 2014, over $36.4 million in TNGVGP grants were awarded for projects to help reduce a 

projected 1,137 tons of NOX. Over $14.8 million in TNGVGP grants were awarded to projects 

where the applicant indicated the primary operation of the vehicle would occur in and around 

the HGB area, with a projected 377 tons of NOX reductions. These projects are estimated to 

reduce up to 0.32 tpd of NOX in the HGB area starting in 2015. The latest grant application 

period ended. An additional$14.5 million in projects were approved for funding, including $2.5 

million for projects in the HGB area. The emissions reductions for these projects will be 

determined after the grants are finalized and final calculations are completed.

HB 1, General Appropriations Bill, 84th Texas Legislature, 2015, appropriated $118.1 million per 

year for implementation of the TERP in FYs 2016 and 2017. This represents an increase of $40.5 

million per year over the appropriation amount in FYs 2014 and 2015. This additional funding 

will be available to fund future grant projects that should result in NOX reductions in the eligible 

TERP areas, including the HGB area.

3.3.9 Low Income Vehicle Repair Assistance, Retrofit, and Accelerated Vehicle Retirement 

Program

The TCEQ established a financial assistance program for qualified owners of vehicles that fail 

the emissions test. The purpose of this voluntary program is to repair or remove older, higher 

emitting vehicles from use in certain counties with high ozone. The Low-Income Vehicle Repair 

Assistance, Retrofit, and Accelerated Vehicle Retirement Program (LIRAP) provisions of HB 

2134, 77th Texas Legislature, 2001, created the program. In 2005, HB 1611, 79th Texas 

Legislature, Regular Session, modified the program to apply only to counties that implement a 

vehicle inspection and maintenance (I/M) program and have elected to implement LIRAP fee 

provisions. Five counties in the HGB area, Brazoria, Fort Bend, Galveston, Harris, and 

Montgomery, are currently participating in the LIRAP.

SB 12, 80th Texas Legislature 2007, expanded LIRAP participation criteria by increasing the 

income eligibility to 300% of the federal poverty rate and increasing the amount of assistance 

toward the replacement of a retired vehicle. HB 3272, 82nd Texas Legislature 2011, Regular 

Session, expanded the class of vehicles eligible for a $3,500 voucher to include hybrid, electric, 

natural gas, and federal Tier 2, Bin 3 or cleaner Bin certification vehicles. The program provides 

$3,500 for a replacement hybrid, electric, natural gas, and federal Tier 2, Bin 3 or cleaner Bin 

certification vehicle of the current model year or the previous three model years; $3,000 for cars 

of the current or three model years; and $3,000 for trucks of the current or previous two model 

years. The retired vehicle must be 10 years old or older or must have failed an emissions test. 

From December 12, 2007 through May 31, 2015, the program has retired and replaced 22,448

vehicles in the HGB area at a cost of $67,404,312.80. During the same period, an additional

17,813 vehicles in the HGB area have had emissions-related repairs at a cost of $9,918,439.09.
Page 33

The total retirement/replacement and repair expenditure for the HGB area from December 12, 

2007 through May 31, 2015 is $77,322,751.89.

HB 1, General Appropriations Bill, 84th Texas Legislature, 2015, appropriated $43.5 million per 

year for FYs 2016 and 2017 to continue this clean air strategy in the 16 participating counties. 

The five counties that participate in the program in the HGB area were allocated approximately 

$20 million per year for the LIRAP for FYs 2016 and 2017. This is an increase of approximately 

$17.5 million per year over the previous biennium.

3.3.10 Local Initiative Projects

Funds are provided to counties participating in the LIRAP for implementation of air quality 

improvement strategies through local projects and initiatives. In the HGB area, Local Initiative 

Projects (LIP) funding is available to the five counties participating in the LIRAP: Brazoria; Fort 

Bend; Galveston; Harris; and Montgomery. HB 1, General Appropriations Bill, 84th Texas 

Legislature, 2015, appropriated $4.8 million per year for FYs 2016 and 2017 to continue this 

clean air strategy. The five HGB area counties were allocated approximately $2.2 million per 

year for FYs 2016 and 2017. This is an increase of approximately $1.9 million per year over the 

previous biennium.

Brazoria, Fort Bend, and Galveston Counties used LIP funds to purchase buses and initiate a 

new park-and-ride transit service in 2010. LIP continues to maintain the park-and-ride funding 

as of 2015. The transit service links county residents with the Texas Medical Center area and 

creates immediate and long-term benefits for reducing emissions and congestion by supporting 

approximately 9,000 commuter trips per month.

Harris County used LIP funds in 2010 to establish the Harris County Clean Air Emissions Task 

Force and initiate an emissions enforcement program. For its first five years, the enforcement 

program targeted high-emitting vehicles, smoking vehicles, and suspicious vehicles to verify that 

the state safety and emissions inspection windshield certificates on these vehicles were 

legitimate and in compliance with air quality standards. The task force’s objective is to reduce 

the number of fraudulent, fictitious, or improperly issued safety and emissions inspection 

windshield certificates. Beginning in March 2015, the task force adjusted its objectives to 

concentrate on the identification of vehicles with counterfeit registration insignia and the 

reduction of fraudulent vehicle inspection reports. The task force has partnered with local and 

state agencies to enforce state laws, codes, rules, and regulations regarding air quality and 

mobile emissions in Harris County. The citizens of Harris County and the entire southeast Texas 

region benefit from this program as a result of the reduction in NOX emissions from each vehicle 

brought into emissions compliance.

Montgomery County used LIP funds for signal light synchronization projects in FY 2010, 2012, 

and 2014. Synchronizing traffic signalization reduces idling by decreasing the number of times a 

vehicle must stop at a traffic light. The “Exhaust Phase” of an engine emits the most emissions 

during starting, idling, and breaking stationary inertia. Synchronizing traffic signalization 

reduces both idling and the number of times a vehicle must resume travel, i.e., break stationary 

inertia. The project increases the emissions reduction benefits by synchronizing the traffic 

signalization upon real-time traffic flow instead of a stagnate model to better manage peak-hour 

congestion, while minimizing cross-traffic congestion, and reducing emissions.

3.3.11 84th Texas Legislature

Bills passed during the 84th Texas Legislature, 2015, that have the potential to impact the HGB 

area are discussed in Section 3.3.5: Energy Efficiency and Renewable Energy Measures and 
Page 34

Section 3.3.9: Low Income Vehicle Repair Assistance, Retrofit, and Accelerated Vehicle 

Retirement Program. As discussed in Section 3.3.9, HB 1 appropriated $43.5 million per year 

for FYs 2016 and 2017 to continue the LIRAP in the 16 participating counties. The five counties 

that participate in this clean air strategy in the HGB area were allocated approximately $20 

million per year for the LIRAP for FYs 2016 and 2017, which can be expected to contribute 

toward progress in meeting air quality goals. This is an increase of approximately $17.5 million 

per year over the previous biennium.

3.4 Control Strategies Summary

The permanent and enforceable VOC and NOX control measures contained in Section 3.2: List 

of Existing Control Measures have resulted in air quality improvement in the HGB area. These 

enforceable measures will remain in place to ensure continued maintenance of the 1997 eighthour ozone NAAQS in the HGB area. In addition, Section 3.3: Additional Measures lists control 

measures that may not meet all of the EPA’s standard tests of SIP creditability (permanent,

enforceable, surplus, and quantifiable) but are crucial to the success of the air quality plan in the 

HGB area. Implementation of these control measures will contribute to the continued 

maintenance of the 1997 eight-hour ozone NAAQS and attainment of the 2008 eight-hour ozone 

NAAQS. The TCEQ continues to seek innovative air quality improvement measures and 

technologies to implement in the HGB area.

SECTION 4: MAINTENANCE DEMONSTRATION

4.1 General

This Houston-Galveston-Brazoria (HGB) Area Redesignation Substitute Report for the 1997 

Eight-Hour Ozone National Ambient Air Quality Standard (NAAQS) is intended to demonstrate 

that the HGB area will remain in attainment of the 1997 eight-hour ozone NAAQS for the 10-

year period following the date that anti-backsliding obligations under the revoked standard 

would be lifted. Since removing anti-backsliding obligations is contingent upon the United 

States Environmental Protection Agency’s (EPA) approval, the Texas Commission on 

Environmental Quality (TCEQ) has set a horizon year of 2028. This 10-year period also aligns 

with the EPA’s requirement of maintenance plans to demonstrate attainment for a 10-year 

period following the date of redesignation.

The most current emissions inventory (EI) data were analyzed as part of this maintenance 

demonstration. The year 2012 was chosen as the base year for the analyses presented in this 

section because it is one of the three years (2012, 2013, and 2014) used to determine the design 

value for the 2014 attainment year and due to periodic inventory data availability. At the time of 

this HGB RS report, the TCEQ was developing the 2014 periodic EI for the HGB area in 

accordance with the EPA’s Air Emissions Reporting Requirements (40 Code of Federal 

Regulations Part 51, Subpart A). The calendar year 2011 periodic inventory was the most recent 

periodic inventory available to develop this HGB RS report inventory. Since 2011 was not one of 

three years used to determine the design value for the 2014 attainment year, the TCEQ 

developed a 2012 base year inventory from available data for area and mobile sources, and used 

the reported calendar year 2012 data for point sources.

Additionally, the 10 years prior to the 2012 base year (2002 through 2011) were analyzed to 

develop historical trend data. During this time, the HGB-area EI showed a significant decrease 

in ozone precursor emissions from all source categories, which contributed to the attainment of 

the 1997 eight-hour ozone NAAQS. These reductions were accomplished through a variety of 

federal, state, and local regulations and programs as detailed below.
Page 35

4.2 Historical Emissions Inventory Trends

For the historical period prior to the 2012 base year, 2002 through 2011, overall anthropogenic 

ozone precursor emissions in the HGB nonattainment area declined substantially as a result of 

regulations implemented at the federal, state, and local levels and innovative programs 

implemented by the TCEQ. As demonstrated in Figure 4-1: HGB Eight-County Nonattainment 

Area Historical NOX Emissions Trends and Figure 4-2: HGB Eight-County Nonattainment 

Area Historical VOC Emissions Trends, anthropogenic volatile organic compounds (VOC) 

emissions have decreased 30%, and anthropogenic nitrogen oxides (NOX) emissions have 

decreased 46%. Both 30 Texas Administrative Code (TAC) Chapter 115: Control of Air Pollution 

from Volatile Organic Compounds and 30 TAC Chapter 117: Control of Air Pollution from 

Nitrogen Compounds regulations along with implementation of the Mass Emissions Cap and 

Trade (MECT) Program have significantly reduced overall ozone precursor emissions at both 

major and minor (point and area) industrial, commercial, and institutional sources in the HGB 

ozone nonattainment area. Innovative emissions reduction programs such as the Texas 

Emissions Reduction Plan and the AirCheckTexas Drive a Clean Machine program in 30 TAC 

Chapter 114: Control of Air Pollution from Motor Vehicles have also reduced mobile source 

emissions, the primary source of NOX emissions in the HGB area.

Figure 4-1: HGB Eight-County Nonattainment Area Historical NOX Emissions 

Trends

27.79 16.04 25.41

21.15

322.20

274.00

208.40

172.10

145.25

156.04

149.24

121.11

339.49

194.52

111.38

108.48

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

2002 2005 2008 2011

Emissions in Tons Per Day

Area

On-Road

Non-Road

Point
Page 36

Figure 4-2: HGB Eight-County Nonattainment Area Historical VOC Emissions 

Trends

4.3 Attainment Inventory Base Year

The 1990 Federal Clean Air Act Amendments require that EIs be prepared for ozone 

nonattainment areas. Because ozone is photochemically produced in the atmosphere when VOC 

mixes with NOX in the presence of sunlight, the TCEQ must compile information on the sources 

of these precursor pollutant emissions. The EI must identify the source types present in an area, 

the amount of each pollutant emitted, and the types of processes and control devices employed 

at stationary sources or other source categories. The EI provides data for a variety of air quality 

planning tasks, including establishing baseline emission levels, calculating reduction targets, 

control strategy development for achieving the required emission reductions, emission inputs 

into air quality simulation models, and tracking actual emission reductions against the 

established emissions growth and control budgets.

The 2012 base year inventory for the HGB area is based on the VOC and NOX emissions that 

occur on a typical summer weekday. Consistent with a September 4, 1992 EPA memorandum 

entitled Procedures for Processing Requests to Redesignate Areas to Attainment, the 

attainment EI base year may be any one of the three years used to determine the design value 

for the attainment year. For this HGB RS report, the attainment EI base year is 2012 and it is 

one of the three years used to determine the design value for the 2014 attainment year. The total 

VOC and NOX EI for the HGB area is summarized from the estimates developed for four general 

categories of anthropogenic emissions sources, which are each explained in Section 4.4.1: Area 

Sources, Section 4.4.2: On-Road Mobile Sources, Section 4.4.3: Non-Road Mobile Sources, and 

116.80

98.60

88.20

73.40

82.79

72.28

62.65

49.92

149.37

140.08

108.10

96.11

422.14

425.83

446.60

308.53

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

450.00

500.00

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

2002 2005 2008 2011

Emissions in Tons Per Day

On-Road

Non-Road

Point

Area
Page 37

Section 4.4.4: Stationary Point Sources. Summaries of the 2012 VOC and NOX emissions by 

source type are provided in Section 4.5: Emissions Summary.

4.4 Future Emissions and Verification of Continued Attainment

To track progress of the HGB area toward continued attainment of the 1997 eight-hour ozone 

NAAQS, the TCEQ will continue to develop and submit periodic emissions inventories (PEIs) to 

the EPA every three years as required by the federal Air Emissions Reporting Requirements 

(AERR) rule. The 2011 inventory was the first PEI submitted under the AERR. As required by 

the AERR, the 2011 PEI was reported to the EPA’s National Emissions Inventory (NEI) as a 

comprehensive and detailed estimate of air emissions, including ozone precursors (NOX and 

VOC). As directed by the AERR, the 2011 Texas PEI includes annual emissions for the entire 

state and summer weekday emissions for the 2008 eight-hour ozone nonattainment areas in 

Texas, including the HGB area. Per the EPA’s Implementation of the 2008 National Ambient 

Air Quality Standards for Ozone: State Implementation Plan Requirements; Final Rule (2008 

ozone standard SIP requirements rule), published in the March 6, 2015 Federal Register (80 FR 

12264), states can rely on periodic AERR EI submittals to satisfy ongoing state implementation 

plan (SIP) EI submission requirements every three years.

Because the EPA has not made guidance available for how to demonstrate continued attainment 

in an RS, the TCEQ is using the method outlined in the EPA’s redesignation guidance12. Future 

emissions for the HGB area were projected from the base year inventory (2012) to a future year 

(horizon year) of 2028. Projecting emissions to 2028 aligns with the EPA’s requirement of 

maintenance plans to demonstrate attainment for a 10-year period following the date of 

redesignation. The requirement for demonstration of continued attainment is satisfied when the 

state demonstrates that future VOC and NOX emissions levels are not expected to result in 

exceedances of the 1997 eight-hour ozone NAAQS.

Future emissions were projected to the horizon year 2028 using two- and three-year intervals to 

align milestone years with periodic AERR EI years as appropriate. A summary of the base year 

inventory and the future year inventories for ozone precursor emissions is presented in Section 

4.5.

4.4.1 Area Sources

Stationary source emissions data from sites and processes that do not meet the reporting 

requirements for point sources are classified as area sources. Area sources are small-scale 

industrial, commercial, and residential sources that generate emissions. Emissions are 

calculated and reported at the county level. Examples of area sources include: printing 

operations; industrial coatings; degreasing solvents; architectural coatings; gasoline service 

station underground tank filling; vehicle refueling operations; stationary source fossil fuel 

combustion; outdoor refuse burning; and structural fires. With some exceptions, area source 

emissions are calculated by multiplying an established emissions factor (emissions per unit of 

activity) by the appropriate activity or activity surrogate responsible for generating emissions. 

Population is one of the more commonly used activity surrogates for area sources. Other activity 

data include the amount of gasoline sold in an area, employment by industry type, and crude oil 

and natural gas production.

 12 Memorandum from John Calcagni, Director of Air Quality Management Division, September 4, 1992, 

Procedures for Processing Requests to Redesignate Areas to Attainment. EPA Office of Air Quality 

Planning and Standards.
Page 38

4.4.1.1 Updated 2012 Base Year Inventories

The updated 2012 base year inventory was formed from the 2011 periodic AERR EI. The 

periodic 2011 inventory was developed per the AERR reporting requirements and was created 

using a combination of methodologies and data: EPA-generated EIs; TCEQ-contracted projects;

TCEQ staff projects; and categories grown from the 2008 EI using factors derived from study 

data compiled by Eastern Research Group (ERG), the Economic and Consumer Credit Analytics

website (http://www.economy.com/default.asp), and the United States Energy Information 

Administration’s (EIA) annual energy outlook publication. The documentation for the 

development of the ERG study factors can be found in Attachment A: Projection Factors for 

Point and Area Sources.

The EPA developed EIs for states to use for many source categories as part of the NEI. The 

states access these individual inventories through the EPA’s NEI website 

(ftp://ftp.epa.gov/EmisInventory/2011nei/doc/). These source categories include but are not 

limited to: industrial coatings; degreasing; residential, commercial/institutional, and industrial 

fuel use; commercial cooking; aviation fuel use; and consumer products. For some source 

categories, the TCEQ developed state-specific emissions estimates by acquiring current statespecific activity data and applying appropriate emissions factors. These source categories 

include but are not limited to: storage tanks, structural fires, dry cleaners, and automobile fires. 

The 2012 base year inventory was grown from the 2011 periodic AERR EI using factors derived 

from Attachment A.

In particular, the TCEQ focused on refining the oil and gas area source inventory production 

categories for the EI. The improvements included the development and refinement of a statespecific oil and gas area source emissions calculator. This oil and gas area source emissions 

calculator uses county-level production and local equipment activity data with local emissions 

requirements to estimate emissions from individual production categories including compressor 

engines, condensate and oil storage tanks, loading operations, mud degassing, pump engines, 

heaters, and dehydrators. The documentation for the development of the oil and gas emissions 

calculator can be found in Attachment B: Characterization of Oil and Gas Production 

Equipment and Develop a Methodology to Estimate Statewide Emissions. A significant 

improvement made to the oil and gas calculator was the development of refined emission factors 

for VOC emissions from condensate storage tanks. The documentation for the refined emission 

factors can be found in Attachment C: Condensate Tank Oil and Gas Activities.

In addition, further improvements were made to the oil and gas calculator through the 

development of region-specific emission factors for mud degassing, updated region-specific 

equipment profiles, and year-specific engine emissions factors for hydraulic pump engines. The 

documentation for these refined factors can be found in Attachment D: Specified Oil and Gas 

Well Activities Emissions Inventory Update. The 2012 base year inventory for oil and gas area 

sources was developed using 2012 activity data and production information from the Railroad 

Commission of Texas (RRC).

For those area source categories affected by TCEQ rules, rule effectiveness factors are applied to 

the baseline or uncontrolled emissions to estimate controlled emissions. These factors address 

the efficiency of the controls and the percentage of the category’s population affected by the rule. 

Quality assurance of area source emissions involves ensuring that the activity data used for each 

separate category is current and valid. Data such as current population figures, fuel usage, and 

material usage were updated and the EPA guidance on emissions factors was used. Other 

routine efforts such as checking calculations for errors and conducting completeness and 

reasonableness checks were implemented.
Page 39

4.4.1.2 Updated Milestone Years Inventories

The updated base year (2012), milestone years (2014, 2017, 2020, 2023, and 2026) and horizon 

year (2028)EIs for the area source categories were developed using factors derived from

Attachment A, the Economic and Consumer Credit Analytics website 

(http://www.economy.com/default.asp), and the EIA’s annual energy outlook publication. The 

ERG-derived factors contain individual growth factors for each category and for each forecasting 

year. This projection method is the EPA standard and accepted method for developing future 

year EIs.

4.4.1.3 Area Source Emissions Inventories

The area source NOX and VOC 2012, 2014, 2017, 2020, 2023, 2026, and 2028 emissions totals 

for the eight-county HGB 1997 eight-hour ozone nonattainment area are presented in Table 4-

1: HGB Area Source NOX and VOC Emissions (tons per day).

Table 4-1: HGB Area Source NOX and VOC Emissions (tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 21.91 22.52 23.23 23.61 23.47 23.50 23.59

VOC 310.07 317.75 328.20 335.07 337.81 341.16 344.75

4.4.2 On-Road Mobile Sources

On-road mobile emission sources consist of automobiles, trucks, motorcycles, and other motor 

vehicles traveling on public roadways. On-road mobile source emissions are usually categorized 

as either combustion-related emissions or evaporative hydrocarbon emissions. Combustionrelated emissions are estimated for vehicle engine exhaust. Evaporative hydrocarbon emissions 

are estimated for the fuel tank and other evaporative-leak sources on the vehicle. To calculate 

emissions, both the rate of emissions per unit of activity (emissions factors) and the number of 

units of activity must be determined. The emissions factors for on-road mobile sources are 

determined using models developed and approved by the EPA. The models allow for input of 

local conditions and vehicle characteristics. The activity information corresponding to the 

emissions factors is obtained using local travel demand models (TDMs), the output from the 

highway performance monitoring system, and speed models.

In March 2010, the EPA released the Motor Vehicle Emissions Simulator (MOVES) model as the 

official emissions factor model for developing on-road mobile source category EIs. Although 

MOVES represented a new approach to assessing on-road emissions, the sources are the same, 

and the opportunity to use local inputs for meteorological conditions, control programs, and 

fleet characteristics remains. When using MOVES in emission-rates mode, emission rates are 

produced for subsets of the on-road fleet, and the emission rates are multiplied by the activity 

level of each vehicle type or source-use type to calculate emissions.

The on-road mobile source category EIs for this HGB RS report were developed using the latest 

version of the MOVES model that is available, MOVES2014. The EPA made MOVES2014 

available on July 31, 2014; officially released the MOVES2014 version of the model as a 

replacement to MOVES2010b for SIP applications on October 7, 2014 (70 FR 60343); and 

released an update to the model on October 27, 2014. The TCEQ, working with the Texas 

Transportation Institute (TTI), recently completed MOVES2014-based 2012, 2014, 2017, 2020, 

2023, 2026, and 2028 on-road emission inventories for the HGB area. The planning 

assumptions, fleet characteristics and vehicle miles traveled (VMT) estimates were updated to 

incorporate the latest available information at the time the inventories were developed.
Page 40

To estimate on-road mobile source emissions, emissions rates calculated by the MOVES model 

are multiplied by the level of vehicle activity. On-road mobile source emissions factors are 

expressed in units of grams per mile, grams per vehicles (evaporative), and grams per hour 

(extended idle mode); therefore, the activity data required to complete the inventory calculation 

are VMT in units of miles per day, vehicle populations, and source hours idling. The level of 

vehicle travel activity is developed using a TDM run by the Texas Department of Transportation 

or by the local metropolitan planning organization. The TDMs are validated against a large 

number of ground counts, i.e., traffic passing over counters placed in various locations 

throughout a county or area. For SIP and reporting inventories, VMT estimates are calibrated 

against outputs from the federal highway performance monitoring system, a model built from a 

different set of traffic counters. Vehicle populations by source type are derived from the Texas 

Department of Motor Vehicle registration database and, as needed, national estimates for 

vehicle source type population.

In addition to the number of miles traveled on each roadway link, the speed on each roadway 

type or segment is also needed to complete an on-road EI. Roadway speeds, required inputs for 

the MOVES model, are calculated by using the activity volumes from the TDM and a postprocessor speed model.

4.4.2.1 On-Road Mobile Source Emissions Inventories

The 2012, 2014, 2017, 2020, 2023, 2026, and 2028 on-road mobile source EIs for this HGB RS

report were developed using the latest available data, current emissions factors and models, and 

the most current planning assumptions. The inventories include the eight HGB-area counties 

designated as nonattainment for the 1997 eight-hour ozone NAAQS. On-road inventory 

estimates were developed under contract by the TTI.

Consistent with on-road inventory development procedures for reporting requirements and 

reasonable further progress demonstrations, the on-road inventories for each of these calendar 

years are based on VMT estimates and emission rates for an average summer weekday. 

MOVES2014, which is the latest available version of the EPA’s MOVES model, was used to 

estimate the summer weekday emission rates in units of grams per mile for NOX and VOC.

Two methods are used to establish VMT: a federal system, the Highway Performance 

Monitoring System (HPMS); and a local system, a TDM. For historical years, the HPMS data 

constitutes the official measurement of highway performance, including VMT. The TDM 

represents the best method for distributing VMT to the roadway links within the local travel 

network and for predicting future year VMT. To provide consistency between the estimates for 

the two systems, the TDM-forecasted VMT estimates are adjusted using a VMT ratio based on 

an historical year for which the TDM was validated and the HPMS data has been made available. 

The 2012 VMT is based upon historical HPMS VMT data and is also the validation year. The 

HPMS data was not available for 2014 or any of the future years; therefore, the VMT for these 

years was forecast using the HGB TDM and adjusted using the 2012 HPMS-to-TDM VMT ratio. 

Year-to-year historical VMT data fluctuates and does not follow a smooth upward trend. The 

decline in VMT between 2012 and 2014 reflects an historical decline in VMT following 2011, 

magnified by the inherent differences between the two VMT estimation methods. A summary of 

the on-road mobile source VMT used to develop the various NOX and VOC emissions levels is 

presented in Table 4-2: HGB VMT (miles per average summer weekday).
Page 41

Table 4-2: HGB VMT (miles per average summer weekday)

Year Vehicle Miles 

Traveled

2012 151,333,456

2014 144,546,685

2017 156,018,423

2020 167,051,752

2023 178,917,689

2026 190,707,272

2028 197,675,678

The HGB on-road mobile source 2012, 2014, 2017, 2020, 2023, 2026, and 2028 EIs for NOX

and VOC are summarized in Table 4-3: HGB Average Summer Weekday NOX and VOC 

Emissions for On-Road Mobile Sources (tons per day). For complete documentation of the 

development of the on-road mobile source EIs for this HGB RS report including the inventory 

development methods, MOVES inputs, and the results, refer to Attachment E: Development of 

HGB On-Road Emissions Inventories for the Years 2012, 2014, 2017, 2020, 2023, 2026, and 

2028. The complete set of input and output files are available from the Emissions Assessment 

Section of the TCEQ Air Quality Division upon request.

Table 4-3: HGB Average Summer Weekday NOX and VOC Emissions for On-Road 

Mobile Sources (tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 159.08 124.64 82.96 61.06 48.94 40.24 37.04

VOC 74.51 61.48 47.36 40.38 36.12 31.71 28.99

4.4.2.2 On-Road Mobile Source Control Strategies

The on-road mobile EIs for each analysis year were developed using MOVES2014 emissions

factors that reflect all control strategies used to demonstrate maintenance of the 1997 eight-hour 

ozone NAAQS. The controls that were modeled include: pre-1990 Federal Motor Vehicle Control 

Program (FMVCP), fleet turnover to Tier 1 of the FMVCP, fleet turnover to Tier 2 of the FMVCP, 

the 2007 heavy duty diesel FMVCP, fleet turnover to Tier 3 of the FMVCP, the lower sulfur 

gasoline associated with Tier 3 FMVCP, National Low Emission Vehicle (NLEV) program,

summer reformulated gasoline (RFG), the HGB vehicle inspection and maintenance (I/M)

program, the HGB anti-tampering program, and Texas Low Emission Diesel (TxLED). A 

summary of the HGB on-road mobile source control strategies used for this HGB RS report are 

presented in Table 4-4: HGB On-Road Mobile Control Strategies Summary.
Page 42

Table 4-4: HGB On-Road Mobile Control Strategies Summary

Control Program 

Description

Year Control 

Program Started Control Scenario Notes

Pre-1990 FMVCP Pre-1990 Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

Anti-Tampering Program 1986 Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

1992 Federal Controls on 

Gasoline Volatility 1992

Maximum Reid Vapor Pressure of 7.8 pounds per 

square inch

Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

Tier 1 FMVCP 1994 Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

RFG Phase 1 1995 for Phase 1 Superseded by RFG Phase 2

I/M Program, Phase 1 1997

Harris County

Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

RFG Phase 2 2000 for Phase 2 Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

NLEV Program 2001 Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

I/M Program, Phase 2 2003

Expanded to include: Brazoria, Fort Bend, Galveston, 

and Montgomery Counties (five counties total)

Included for 2012, 2014, 2017, 2020, 2023, 2026,

and 2028

Tier 2 FMVCP 2004

Phased in from 2004 to 2009

Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

TxLED 2006

Low aromatic hydrocarbon and high cetane number 

to control NOX

Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

Federal Low-Sulfur 

Highway Diesel 2006

15 parts per million (ppm) maximum sulfur content

Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

2007 Heavy Duty FMVCP 2007

Phased in from 2007 to 2010

Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

Tier 3 FMVCP 2017 Will be phased in from 2017 to 2025

Lower sulfur gasoline 

associated with Tier 3 

FMVCP

2017 10 ppm maximum for sulfur
Page 43

4.4.2.3 On-Road Mobile Source Control Strategy Reductions

Due to the on-road mobile source control programs in place for each analysis year in 

conjunction with fleet turnover, the on-road NOX and VOC emissions are steadily decreasing 

from the base year of 2012 to each milestone year and the 2028 horizon year despite projected

growth for milestone years 2017, 2020, 2023, 2026, and 2028 in VMT. A summary of the tons 

per day (tpd) change from the 2012 base year to each milestone year and the horizon year are 

summarized in Table 4-5: Estimated Reductions from 2012 Baseline Due to FMVCP, I/M, RFG, 

and TxLED (tons per day). A summary of the percent change in NOX and VOC from the 2012

base year to each milestone year and the horizon year are summarized in Table 4-6: Estimated 

Percent Reductions from 2012 Baseline Due to FMVCP, I/M, RFG, and TxLED.

Table 4-5: Estimated Reductions from 2012 Baseline Due to FMVCP, I/M, RFG, 

and TxLED (tons per day)

Inventory Year NOX (tons per day) VOC (tons per day)

2012 0 0

2014 -34.44 -13.03

2017 -76.12 -27.15

2020 -98.02 -34.13

2023 -110.14 -38.39

2026 -118.84 -42.80

2028 -122.04 -45.52

Table 4-6: Estimated Percent Reductions from 2012 Baseline Due to FMVCP, I/M, 

RFG, and TxLED

Inventory Year NOX % Reductions VOC % Reductions

2012 0.0 0.0

2014 -21.6 -17.5

2017 -47.9 -36.4

2020 -61.6 -45.8

2023 -69.2 -51.5

2026 -74.7 -57.4

2028 -76.7 -61.1

4.4.3 Non-Road Mobile Sources

Non-road vehicles do not typically operate on roads or highways and are often referred to as offroad or off-highway vehicles. The non-road source category is composed of a diverse collection 

of equipment. Non-road emissions sources include but are not limited to: agricultural 

equipment, construction and mining equipment, lawn and garden equipment, aircraft and 

airport equipment, locomotives, commercial marine vessels (CMV), and drilling rigs. EIs for 

non-road sources developed as subcategories include: NONROAD model categories, airports, 

CMVs, drilling rigs, and locomotives. The following sections describe the emissions calculation 

methods used for the non-road mobile source subcategories.
Page 44

4.4.3.1 Updated 2012 Base Year Inventories

A Texas-specific version of the EPA’s latest NONROAD 2008a model, called the Texas 

NONROAD (TexN) model, was used to calculate emissions for all non-road mobile source 

equipment and recreational vehicles, with the exception of airports, locomotives, CMVs, and 

drilling rigs. Several equipment survey studies have been conducted that focused on various 

equipment categories operating in different areas in Texas. The resulting survey data are used as 

inputs to the TexN model to more accurately estimate non-road emissions for the State of Texas 

instead of using the national default values in the EPA’s NONROAD 2008a model. 

Documentation of methods and procedures used in developing NONROAD model category EIs 

can be found in Attachment F: Development of Air Emissions Inventories for NONROAD Model 

Category Mobile Sources (Task 3).

The United States Federal Aviation Administration’s Emissions and Dispersion Modeling 

System, Version 5.1.3 (EDMS) was used with updated activity data to calculate airport source 

emissions. These airport emission sources include aircraft engines, auxiliary power units, and 

ground support equipment. To estimate the emissions from the airport sources, a survey was 

conducted by ERG under contract with the TCEQ to collect updated information on aircraft 

activity, fleet mix, and other EDMS model input parameters. Documentation of methods and 

procedures used in developing airport EIs can be found in Attachment G: Airport Emissions 

Inventories for Houston-Galveston-Brazoria and Dallas-Fort Worth Areas for Select Years 

2012, 2014, 2017, 2020, 2023, 2026, and 2028.

The 2012 Texas locomotive EI includes Class I, II, and III locomotive activity and emissions by 

rail segment for all counties within Texas. Locomotive line-haul and yard activity data were 

compiled from companies operating in Texas and from additional resources identified by 

contractor ERG to create a county-level Class I line-haul inventory. Data developed by Eastern 

Regional Technical Advisory Committee in collaboration with the Federal Railroad 

Administration, the American Short Line and Regional Railroad Association (ASLRRA), and 

members of the Class II and III railroad communities used 2008 activity and emissions profiles 

for Class II and Class III railroads. To calculate annual gallons of fuel used by railroads, data 

compiled by ASLRRA from the Class II and III railroads, including total industry fuel use in 

2008 for locomotives and total Class II/III route miles, were used. Based on the EIA’s latest 

annual energy outlook publication, 2008 fuel usage values were grown to estimate 2012

emissions. Documentation of methods and procedures used in developing the locomotive EIs 

can be found in Attachment H: Controlled and Uncontrolled Average Summer Weekday 

Locomotive Inventories for Houston-Galveston-Brazoria and Dallas-Fort Worth Areas for 

Select Years 2012, 2014, 2017, 2020, 2023, 2026, and 2028.

The 2012 CMV EI was based on 2013 activity data compiled using local port data and data from 

the United States Department of Transportation Maritime Administration. Emissions factors 

provided from the EPA’s Office of Transportation and Air Quality were used to account for 

vessel turnover and compliance with marine vessel air quality regulations. The emissions factors 

were applied to the 2013 activity values and then back-casted to calculate 2012 emissions. 

Documentation of methodologies and procedures used in developing the CMV EIs can be found 

in Attachment I: Controlled and Uncontrolled Average Summer Weekday Commercial Marine 

Vessel Inventories for Houston-Galveston-Brazoria Area for Select Years 2012, 2014, 2017, 

2020, 2023, 2026, and 2028.

The 2012 inventory for drilling rig diesel engines was developed based on a statewide EI 

improvement study and updated with 2012 activity data. A survey of oil and gas exploration and 

production companies was used to develop improved drilling rig emissions characterization 
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profiles. Documentation of methods and procedures used in developing the drilling rig diesel 

engine EIs can be found in Attachment J: Development of Texas Statewide Drilling Rigs 

Emissions Inventories for the Years 1990, 1993, 1996, and 1999 through 2040 or online 

at http://www.tceq.texas.gov/assets/public/implementation/air/am/contracts/reports/ei/5821

199776FY1105-20110815-ergi-drilling_rig_ei.pdf. The drilling rig emissions characterization 

profiles from this study were combined with 2012 drilling activity data obtained from the RRC 

to develop the 2012 inventory.

4.4.3.2 Updated Milestone Years Inventories

The updated milestone year inventories for the NONROAD model categories were developed by 

ERG using the latest version of the TexN model (version 1.7.1), which incorporates all of the 

latest available data updates. ERG developed average summer weekday emissions for VOC and 

NOX for the analysis years 2012, 2014, 2017, 2020, 2023, 2026, and 2028. The TexN model 

contains unique population files for all 254 Texas counties that have been developed for every 

possible analysis year (1970 to 2050) within the TexN model, using county and source category 

classification-specific growth factors. Due to fluctuations in engine activity and their associated 

surrogates, the TexN population files are periodically updated using the most recent growth 

factors such as those available on the Economic and Consumer Credit Analytics website 

(https://www.economy.com) to allow for more accurate forecasting and back-casting of 

emissions.

The updated milestone year inventories for the following source categories can be found in the 

attachments listed below.

• NONROAD model category mobile sources inventories were based on the ERG study found 

in Attachment F.

• Airport source inventories were based on the ERG study found in Attachment G.

• Locomotive inventories were based on the ERG study found in Attachment H.

• CMV source inventories were based on the ERG study found in Attachment I.

The updated milestone year inventories for drilling rigs were based on the 2012 inventory 

developed using the drilling rig emissions characterization profiles from the ERG report in 

Attachment J combined with 2012 drilling rig activity data from the RRC. The 2012 inventory 

was then projected to future years using growth factors. Documentation on the development of 

growth factors can be found in Attachment A.

4.4.3.3 Non-Road Mobile Source Emissions Inventories

The 2012 through 2028 milestone year non-road category source NOX and VOC emissions totals 

for the eight-county HGB area are presented in Table 4-7: HGB NOX Emissions for Non-Road 

EI Categories (tons per day) and Table 4-8: HGB VOC Emissions for Non-Road EI Categories 

(tons per day).
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Table 4-7: HGB NOX Emissions for Non-Road EI Categories (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

NONROAD Model 51.88 45.68 36.01 28.36 24.30 22.06 21.21

Airport 6.19 6.48 6.99 7.51 7.89 8.65 8.91

Locomotive 17.27 16.82 14.63 13.44 12.10 10.24 9.18

Commercial Marine 

Vessels

56.00 31.03 28.77 26.08 24.68 22.89 21.36

Drilling Rigs 0.90 0.89 0.92 0.95 0.94 0.94 0.96

Total 132.24 100.90 87.32 76.34 69.91 64.78 61.62

Table 4-8: HGB VOC Emissions for Non-Road EI Categories (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

NONROAD Model 39.38 34.45 29.40 26.71 25.75 25.49 25.57

Airport 2.09 2.24 2.16 2.30 2.40 2.48 2.54

Locomotive 0.99 0.91 0.73 0.62 0.56 0.47 0.41

Commercial Marine 

Vessels

1.49 1.15 1.15 1.19 1.27 1.33 1.34

Drilling Rigs 0.06 0.06 0.07 0.07 0.07 0.07 0.07

Total 44.01 38.81 33.51 30.89 30.05 29.84 29.93

4.4.4 Stationary Point Sources

4.4.4.1 Emissions Inventory Development

Stationary point source emissions data are collected annually from sites that meet the reporting 

requirements of 30 TAC §101.10. This rule, referred to as the TCEQ emissions inventory 

reporting rule, establishes EI reporting thresholds in ozone nonattainment areas that are 

currently at or less than major source thresholds in the HGB ozone nonattainment area. 

Therefore, some minor sources in the HGB ozone nonattainment area report to the point source 

EI.

To collect the data, the TCEQ sends notices to all sites identified as potentially meeting the 

reporting requirements. Companies are required to report emissions data and to provide sample 

calculations used to determine the emissions. Information characterizing the process 

equipment, the abatement units, and the emission points is also required.

All data submitted in the emissions inventory questionnaire (EIQ) are reviewed for qualityassurance purposes and then stored in the State of Texas Air Reporting System (STARS) 

database. EIQ guidance documents and historical point source emissions of criteria pollutants 

are available on the TCEQ’s Point Source Emissions Inventory Web page 

(https://www.tceq.texas.gov/airquality/point-source-ei/psei.html). Additional information is 

available upon request from the TCEQ’s Air Quality Division.

4.4.4.2 Updated 2012 Base Year Inventory

The TCEQ extracted the 2012 point source inventory data from STARS on February 13, 2015. 

The extracted data included reported annual and ozone season daily emissions of NOX and VOC 
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for each site in the HGB area that submitted a 2012 EIQ and reflected revisions made on or 

before the extract date.

4.4.4.3 Updated Milestone Years Inventories

The TCEQ designated the 2013 EI as the starting point for emission inventory projections for 

each of the milestone years because it was the most recent EI data available. Using the most 

recent point source EI data captures the most recent economic conditions and any recent 

applicable controls, which can improve the accuracy of emissions projections. The TCEQ 

extracted the 2013 point source inventory data from STARS on February 26, 2015. The extracted 

data included reported annual and ozone season daily emissions of NOX and VOC for each site 

in the HGB area that submitted a 2013 EIQ and reflected revisions made on or before the extract 

date.

In the development of the milestone year inventories for each ozone precursor (NOX and VOC), 

the TCEQ projected future emissions from major and minor sources separately when 

appropriate and then added unused emissions reductions credits to the inventories. Further 

details are explained below. Title V operating permit data were reviewed to identify sites that 

were major for ozone precursors.

For both major and minor sources, NOX emissions from equipment applicable to the MECT 

Program were projected using MECT data. MECT data were retrieved from the emissions 

banking and trading database and reviewed to identify sites with applicable units. For both 

major and minor sources, it was assumed that the significant majority of NOX emissions are 

from MECT-applicable units. Since the MECT cap is an annual value, it was prorated by the 

ratio of the aggregate of the 2013 ozone season daily emissions to the aggregate of the 2013

annual emissions for applicable sites to project future daily emissions for the HGB area. To 

maintain a conservative approach, the entire cap was applied to the aggregate of the site-level

emissions in the first milestone year inventory.

Title V operating permit data from 2014 were reviewed to identify major sources of VOC 

emissions. VOC emissions from these sites were projected by adding emissions growth allowed 

under the major modification thresholds for marginal ozone nonattainment areas. For each site, 

the annual 40-ton major modification threshold was prorated by the site-wide ratio of ozone 

season to annual emissions to provide a one-time growth in emissions that was added to the 

site’s 2013 emissions. To maintain a conservative approach, all growth was taken into account 

by 2014, the first milestone year inventory.

NOX emissions from sites not listed in the MECT Program and VOC emissions from sources not 

identified as major sources of VOC emissions were assumed to be minor source emissions and

were projected using emissions trend data and growth factors for each milestone year. The 

documentation for the development of the emissions growth factors can be found in Attachment

A. Emission trends for each site were established using 2009 through 2013 annual emissions 

data. For sites with decreasing emission trends, milestone year inventories were set equal to the 

2013 baseline inventory. For sites with increasing emission trends, milestone year inventories 

were determined by applying growth factors to the 2013 baseline inventory. The growth factor 

information can be found in Attachment A. To maintain a conservative approach, any growth 

factors that projected a decrease in future emissions (i.e., negative growth) were modified so 

that emissions for these source categories remained equal to the 2013 baseline inventory 

through future years.

Finally, each of the milestone year inventories were adjusted to account for available (unused) 

emissions credits. Emissions credits are banked emissions reductions that may return to the air 
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shed in the future through the use of these emissions credits either to modify existing facilities, 

construct new facilities, or by facilities to demonstrate compliance with emissions limit 

obligations where provided for in commission rules. To account for the possible use of the 

banked NOX and VOC emissions, available emissions reduction credit (ERC) and discrete 

emissions reduction credit (DERC) data were added to the inventories as discussed below.

Projected ERC use was determined by assuming that banked ERCs would be used for offsets in 

permitting new or modified sources. In ozone nonattainment areas, ERCs used to permit new or 

modified sources must be reduced by a factor called the offset ratio to assist with ensuring 

progress towards attaining air quality standards. Therefore, available ERCs were reduced by 15% 

(i.e., divided by 1.15) to account for the Nonattainment New Source Review permitting offset 

ratio for marginal ozone nonattainment areas. All available ERCs listed in the emissions banking 

and trading database as of February 13, 2015 were added to each milestone year starting with 

2017. This includes transactions with available information from 2008 through 2014 to account 

for credits taken from the bank and applied to projects that may not have been completed in 

time for the 2013 inventory.

Projected DERC use was determined by assuming that all available credits would be used over 

the 2017 through 2028 timespan. The resulting credits were averaged over the 2017 through 

2028 projected timespan to obtain a daily contribution and added to the projected inventories. 

This approach is conservative and simplified; historical use has been considerably less (less than 

10% of the projected rate)13 and this is not anticipated to change significantly. The DERC 

transactions between 2008 and 2014 were not added as they were used for one-time compliance 

projects applicable to, and reflected in, emissions for those years only. A summary of the 2012, 

2014, 2017, 2020, 2023, 2026, and 2028 point source EIs is presented in Table 4-9: HGB Point 

Source NOX and VOC Emissions (tons per day).

Table 4-9: HGB Point Source NOX and VOC Emissions (tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 98.50 119.67 127.39 127.71 128.03 128.35 128.56

VOC 84.06 110.72 115.02 115.65 116.26 116.94 117.41

4.5 Emissions Summary

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 4-10: HGB NOX Emissions by Source 

Category (tons per day) and Table 4-11: HGB VOC Emissions by Source Category (tons per 

day). These tables illustrate that in the horizon year of 2028, point sources contribute the most 

NOX emissions and area sources contribute the most VOC emissions. Contributions from 

biogenic emissions are not included in the summary because this analysis is limited to 

anthropogenic sources.

 13 Texas Commission on Environmental Quality. “Discrete Emission Credit Banking and Trading Program 

Audit.” Accessed March 6, 2014. http://www.tceq.texas.gov/assets/public/implementation/air/banking

/reports/2013decprogramaudit.pdf.
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Table 4-10: HGB NOX Emissions by Source Category (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Point Sources 98.50 119.67 127.39 127.71 128.03 128.35 128.56

Area Sources 21.91 22.52 23.23 23.61 23.47 23.50 23.59

On-Road Mobile 

Sources (MOVES2014) 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 4-11: HGB VOC Emissions by Source Category (tons per day)

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 (MOVES2014) 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

4.6 Maintenance Demonstration Conclusion

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.

Previous photochemical modeling analysis for the HGB area shows that reducing NOX

emissions is expected to be more effective in reducing the ozone design value than VOC 

reductions. Therefore, the projected 160.92 tpd decrease of NOX is expected to reduce ozone 

design values effectively despite the small projected 8.43 tpd increase in VOC emissions. Based 

on future expected trends and previous photochemical analysis, the HGB area is projected to 

show continued attainment of the 1997 eight-hour ozone standard through 2028.