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

DALLAS-FORT WORTH (DFW) ONE-HOUR AND 1997 EIGHT-HOUR 

OZONE STANDARD NONATTAINMENT AREAS

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 Dallas-Fort Worth (DFW) One-Hour and 1997 

Eight-Hour Ozone nonattainment areas 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 12264).

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 National 

Ambient Air Quality Standard (NAAQS) with a design value of 124 ppb based on certified 

monitoring data from 2004 through 2006, and continues to demonstrate attainment with a 

design value of 102 ppb based on certified data through 2014. On October 16, 2008, the EPA 

published final determination that the DFW four-county nonattainment area had attained the 

one-hour ozone standard (73 FR 61357).

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

Johnson, Kaufman, Parker, Rockwall, and Tarrant Counties. On February 24, 2015, the TCEQ 

submitted early certification of 2014 ozone air monitoring data to the EPA, along with a request 

for a determination of attainment for the 1997 eight-hour ozone standard for the nine-county 

DFW area with a design value of 81 ppb based on monitoring data from 2012, 2013, and 2014. 

On April 28, 2015, the EPA published a proposed clean data determination for the DFW 1997 

eight-hour ozone nonattainment area (80 FR 23487). As of August 4, 2015, the 1997 eight-hour 

ozone design value is 80 ppb.

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.

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

obligations for the revoked one-hour and the revoked 1997 eight-hour ozone NAAQS by 

ensuring that specific redesignation requirements are met for the DFW four-county one-hour 

and nine-county 1997 eight-hour ozone nonattainment areas. This DFW RS report is being

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 requires 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 one-hour and 1997 

eight-hour ozone NAAQS upon the EPA’s approval of the one-hour and 1997 eight-hour ozone 

DFW RS report. With this DFW RS report, the TCEQ requests that the EPA concur that the 

DFW areas are attaining and will continue to attain the revoked one-hour and revoked 1997 

eight-hour ozone NAAQS, and that the nonattainment NSR provisions for the revoked standards 

no longer apply to the areas.

Certified ambient air quality monitoring data for 2004 through 2006 demonstrate that the fourcounty DFW area monitored attainment of the one-hour ozone NAAQS starting in 2006 with a 

design value of 124 ppb, and continues to demonstrate attainment with a design value of 102 

ppb based on certified data through 2014. The nine-county DFW area demonstrates attainment 

of the 1997 eight-hour ozone NAAQS with a design value of 81 ppb based on certified data from 
Page 2

2012 through 2014. This DFW RS report further supports the demonstration that the DFW 

areas will continue to attain the one-hour and 1997 eight-hour ozone standard due to permanent 

and enforceable emission reductions and demonstrates continued attainment of both standards 

through 2028 via emissions 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.

Consistent with the EPA’s 2008 ozone standard SIP requirements rule, this DFW RS report for 

the one-hour and 1997 eight-hour ozone NAAQS includes the following elements.

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

NAAQS

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

ozone data and trend analyses. The DFW four-county area attained the one-hour ozone standard 

with a design value of 124 parts per billion (ppb), based on certified 2004 through 2006 

monitoring data. The 2012 through 2014 certified monitoring data for the nine-county DFW 

area demonstrate that the area is monitoring attainment of the 1997 eight-hour ozone NAAQS 

with a design value of 81 ppb. Ozone concentrations have decreased dramatically in the DFW

areas since the 1990s. Examination of the trends in one-hour and eight-hour ozone design 

values reveals substantial downward trends in monitored ozone levels.

Showing That Attainment Was Due to Permanent and Enforceable Emissions Reductions

Section 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 DFW fourcounty one-hour and nine-county 1997 eight-hour ozone nonattainment areas. 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 have significantly reduced overall ozone precursor emissions in the DFW areas. The 

DFW areas have attained the one-hour and 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 one-hour and 1997 eight-hour ozone NAAQS in the 

DFW areas.

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

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

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

of the one-hour and 1997 eight-hour ozone standards through 2028. Analysis of projected ozone 

precursor emissions from 2012 through 2028 shows an overall projected decrease of 207.32 

tons per day (tpd) in combined NOX and VOC emissions for the DFW four-county one-hour 

ozone nonattainment area. This net change for the four-county area includes a projected 61.09 

tpd decrease in VOC and a 146.23 tpd decrease in NOX. For the DFW nine-county 1997 eighthour ozone nonattainment area, the trend analysis shows an overall decrease of 257.04 tpd in 

combined NOX and VOC emissions. The net change for the nine-county area includes a 

projected 83.86 tpd decrease in VOC and a 173.18 tpd decrease in NOX. Based on emissions 

projections and previous photochemical modeling analysis, continued attainment of the onehour and 1997 eight-hour ozone standards are shown for the four-county and nine-county DFW 

areas through 2028.
Page 3

1.2 Ozone NAAQS History

The following history of the one-hour and eight-hour ozone standards and summaries of the 

DFW area one-hour and 1997 eight-hour ozone SIP revisions are provided to give context and 

greater understanding of the complex issues involved in attaining the ozone standard in the 

DFW area.

1.2.1 One-Hour Ozone NAAQS History

The EPA established the one-hour ozone NAAQS of 0.08 parts per million (ppm) in the April 

30, 1971 issue of the Federal Register (36 FR 8186). The EPA revised the one-hour ozone 

standard to 0.12 ppm on February 8, 1979 (44 FR 4202). The DFW four-county one-hour ozone 

nonattainment area (Collin, Dallas, Denton, and Tarrant Counties) was designated in 1991 as 

moderate in accordance with the 1990 FCAA Amendments (56 FR 56694). As a moderate 

nonattainment area, the four-county DFW area was required to demonstrate attainment of the 

one-hour ozone standard by November 15, 1996. Ambient air monitoring data for the years 1994 

through 1996, however, showed that the one-hour ozone standard was exceeded more than one 

day per year over the three-year period. As a result, the EPA reclassified the four-county DFW 

area from a moderate to a serious nonattainment area (effective March 20, 1998) for failure to 

attain the one-hour ozone standard by the November 1996 deadline (63 FR 8128). The EPA 

required the State of Texas to submit a SIP revision within one year that demonstrated 

attainment of the one-hour ozone NAAQS and addressed FCAA requirements for serious ozone 

nonattainment areas.

1.2.1.1 March 1999

The TCEQ submitted the Attainment Demonstration (AD) for the Dallas-Fort Worth Ozone 

Nonattainment Area SIP revision, which contained a rate-of-progress (ROP) demonstration, to 

the EPA on March 18, 1999. The photochemical modeling contained in the revision indicated 

that additional reductions in NOX emissions would be needed to attain the standard by 

November 1999. The following rules were developed and included in the SIP revision:

 reasonably available control technology (RACT) for NOX point sources;

 nonattainment new source review for NOX point sources; and

 revisions resulting from the change in the major source threshold for RACT applicability for 

VOC.

Additionally, the commission indicated that, due to time constraints, the ROP demonstration for 

the serious classification would not incorporate all rules that were necessary to bring the DFW 

nonattainment area into attainment by the November 1999 deadline and that a complete AD 

would be submitted in the spring of 2000. The EPA determined that the AD and ROP 

demonstrations were incomplete.

Additional local control strategies were necessary for the DFW nonattainment area to reach 

attainment. To develop further control strategy options to augment the federal and state 

programs in the AD and ROP SIP revision, the DFW area established the North Texas Clean Air 

Steering Committee. The committee members included local elected officials, business leaders, 

and other community stakeholders. This committee identified specific control strategies for 

review by technical subcommittee members.
Page 4

1.2.1.2 April 2000

On April 19, 2000, the commission adopted a SIP revision and associated rules for the DFW 

one-hour ozone AD. The April 2000 One-Hour Ozone AD SIP revision contained a number of 

control strategies and the following elements:

 a modeling demonstration that showed air quality in the DFW nonattainment area was 

influenced at times by transport from the Houston-Galveston-Brazoria (HGB)

nonattainment area (Under the EPA’s July 16, 1998 transport policy1, if photochemical 

modeling demonstrated that emissions from an upwind area located in the same state and 

with a later attainment date interfered with the downwind area’s ability to attain, the 

downwind area’s attainment date could be extended to no later than that of the upwind area. 

For the DFW nonattainment area, following this policy would extend the attainment date to 

November 15, 2007, the same attainment date as the HGB area.);

 photochemical modeling of specific control measures and future state and national rules for 

attainment of the one-hour ozone standard in the DFW nonattainment area by the 

attainment deadline of November 15, 2007;

 identification of the VOC and NOX emissions reductions necessary to attain the one-hour 

ozone standard by 2007. The reductions of 141 tpd NOX from federal measures and 225 tpd 

NOX from state measures resulted in a total of 366 tpd NOX reductions for the AD;

 a 2007 motor vehicle emissions budget (MVEB) for transportation conformity; and

 a commitment to perform and submit a mid-course review by May 1, 2004.

At the time it was submitted, the April 2000 One-Hour Ozone AD SIP revision allowed the EPA 

to determine that the DFW nonattainment area should not be reclassified from serious to severe 

under the conditions of the EPA’s July 16, 1998 transport policy.

The Inspection Maintenance (I/M) program was implemented in the DFW nonattainment area 

on May 1, 2002 in Collin, Dallas, Denton, and Tarrant Counties and on May 1, 2003 in Ellis, 

Johnson, Kaufman, Parker, and Rockwall Counties. For more information on the I/M program, 

see Table 3-1: Existing Ozone Control Measures Applicable to the DFW Nonattainment Area.

1.2.1.3 August 2001

The next commission action was required by legislative mandate. Senate Bill (SB) 5, passed by 

the 77th Texas Legislature in May 2001, required the repeal of two rules contained in the April 

2000 one-hour AD SIP revision. The first rule restricted the use of construction and industrial 

equipment (non-road, heavy-duty diesel equipment rated at 50 horsepower (hp) or greater). The 

second rule required the replacement of diesel-powered construction, industrial, commercial, 

and lawn and garden equipment rated at 50 hp or greater with newer Tier 2 or Tier 3 

equipment. The Texas Emissions Reduction Plan grant incentive program established by SB 5 

replaced the NOX emissions reductions previously claimed for the two programs. The 

commission implemented the legislative mandate of SB 5 by submitting the rule repeals as part 

of a SIP revision adopted in August 2001.

1.2.1.4 March 2003

On March 5, 2003, the SIP was further revised to include the following:

 

1 Additional information on the EPA’s Guidance on Extension of Attainment Dates for Downwind 

Transport Areas is available at http://www.epa.gov/ttn/oarpg/t1/memoranda/transpor.pdf.
Page 5

 the adoption of revised 30 Texas Administrative Code (TAC) Chapter 117 NOX emission 

limits for cement kilns;

 the estimation of NOX reductions from energy efficiency measures, using a methodology that 

was to be further refined before energy efficiency credit was formally requested in the SIP 

revision; and

 the commitment to perform modeling with MOBILE6, the latest version of the EPA’s

emission factor model for mobile sources at that time.

Meanwhile, the EPA’s July 16, 1998 transport policy, on which the extension of the DFW

nonattainment area’s attainment date to November 15, 2007 was based, was challenged by 

environmental groups. A suit was filed challenging the extension of the Beaumont-Port Arthur 

(BPA) area’s attainment date based on transport from the HGB area. On December 11, 2002, the 

United States Fifth Circuit Court of Appeals ruled that the EPA was not authorized to extend the

BPA area’s attainment date based on transport. The EPA published a final action in the Federal 

Register on March 30, 2004 reclassifying the BPA area to serious with an attainment date of 

November 15, 2005 and requiring a new AD to be submitted by April 30, 2005. Although the 

court decision was specifically for the BPA area, the direct implication for the DFW 

nonattainment area was that the EPA could not approve extensions of the DFW one-hour ozone 

attainment date past 1999, the date mandated by the FCAA for serious areas. In addition, the 

EPA did not approve the April 2000 One-Hour Ozone DFW AD SIP revision.

1.2.1.5 EPA Determination of One-Hour Ozone Attainment

Since the early 1990s, when the DFW area was designated as nonattainment for the one-hour 

ozone standard, much has been done to bring the area into attainment with federal air quality 

standards. Contributions to improved air quality in the DFW nonattainment area include: 

TCEQ-implemented control strategies, local control strategies adopted by the North Central 

Texas Council of Governments (NCTCOG), and on-road and non-road mobile source measures 

implemented by the EPA. Despite the EPA’s lack of approval for multiple SIP revisions, air 

quality in the DFW nonattainment area continued to improve.

By 2006, certified ambient monitoring data reflected attainment of the one-hour standard. On 

October 16, 2008, the EPA published a final determination (73 FR 61357) that the DFW area 

one-hour ozone nonattainment counties (Collin, Dallas, Denton, and Tarrant) had attained the 

one-hour ozone standard with a design value of 124 ppb, based on certified 2004 through 2006 

ambient monitoring data. The four-county DFW area continues to demonstrate attainment of 

the one-hour ozone NAAQS with certified data for 2012 through 2014. 

1.2.2 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, the 

nine-county DFW area (Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and 

Tarrant Counties) was designated as nonattainment with a moderate classification in the first 

phase of the EPA's implementation rule for the 1997 eight-hour ozone NAAQS (69 FR 23951). 

The TCEQ was required to submit a SIP revision for the 1997 eight-hour ozone NAAQS to the 

EPA by June 15, 2007, and demonstrate attainment of the standard by June 15, 2010. 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). To 

satisfy the requirements of Phase I of the 1997 eight-hour ozone standard implementation rule 
Page 6

(69 FR 23951), the TCEQ adopted the DFW Eight-Hour Ozone Five Percent Increment of 

Progress SIP Revision on April 27, 2005 and submitted it to the EPA. The revision used a 5% 

increment of progress from the area’s 2002 emissions baseline beyond the reductions from 

federal and state measures already approved by the EPA, and was the first DFW SIP revision 

submitted under the 1997 eight-hour ozone standard.

1.2.2.1 May 23, 2007

The commission adopted the May 2007 DFW AD SIP revision and the reasonable further 

progress (RFP) SIP revision for the DFW nonattainment area on May 23, 2007. These SIP 

revisions were the first step in addressing the 1997 eight-hour ozone standard in the DFW 

nonattainment area.

This eight-hour ozone SIP revision for the DFW nonattainment area contained photochemical 

modeling and weight of evidence, including corroborative analysis and additional measures not 

included in the model. In addition to the existing control strategies in the DFW nonattainment 

area, the SIP revision included new rules for the following sources:

 DFW nonattainment area cement kilns;

 DFW nonattainment area electric generating units;

 DFW nonattainment area industrial, commercial, and institutional major sources;

 DFW nonattainment area minor sources; and

 East Texas combustion sources in 33 counties beyond the DFW nonattainment area.

The SIP revision included additional commitments for a Voluntary Mobile Emissions Reduction 

Program (VMEP) and transportation control measures (TCM). The revision also contained the 

reasonably available control measure (RACM) analysis, RACT analysis, contingency measures, 

emissions inventories, and MVEBs.

On July 14, 2008, the EPA proposed conditional approval (73 FR 40203) of the May 2007 DFW 

AD SIP Revision, providing that final conditional approval was contingent upon the State of 

Texas adopting and submitting to the EPA an approvable contingency plan SIP revision for the 

DFW nonattainment area. The DFW AD SIP Revision for the 1997 Eight-Hour Ozone Standard 

(Contingency Measures Plan) was adopted by the commission on November 5, 2008 and 

submitted to the EPA on November 15, 2008. The SIP revision identified measures to satisfy the 

EPA’s 3% reduction contingency requirement for 2010 for the DFW nonattainment area, to 

apply in the event that the DFW nonattainment area failed to meet the 1997 eight-hour ozone 

standard by the attainment deadline.

An additional condition stipulated by the EPA for final approval of the May 2007 DFW AD SIP 

Revision was that the TCEQ adopt and submit rule and SIP revisions to implement an 

enforceable mechanism to limit the use of discrete emission reduction credits (DERC) in the 

DFW nonattainment area by March 1, 2009. The DFW AD SIP Revision for the 1997 Eight-Hour 

Ozone Standard DERC Program incorporated rulemaking that amended Chapter 101, 

Subchapter H, Division 4: Discrete Emission Credit Banking and Trading rules to set a limit on 

DERC use for the DFW nonattainment area.

On January 14, 2009, the EPA published final conditional approval of components of the 2007 

AD SIP revision, including the May 2007 DFW AD SIP revision, and the April 2008 and 

November 2008 supplements. The approval provided conditional approval of the 2009 

attainment MVEBs, RACM demonstration, and failure-to-attain contingency plan, full approval 

of local VMEP and TCMs, full approval of the VOC RACT demonstrations for the one-hour and 
Page 7

1997 eight-hour ozone standards, and a statement that all control measures and reductions 

relied upon to demonstrate attainment were approved by the EPA.

On March 10, 2010, the commission adopted the DFW RACT Update, 30 TAC Chapter 117 Rule 

Revision Noninterference Demonstration, and Modified Failure-to-Attain Contingency Plan SIP 

Revision. This SIP revision incorporated several actions adopted by the commission, and 

supplemented the 1997 eight-hour ozone AD by demonstrating that the revised Chapter 117 rule 

does not interfere with the DFW AD SIP Revision.

On August 25, 2010, the commission adopted a SIP revision to convert an environmental speed 

limit (ESL) control strategy to a TCM for the 1997 eight-hour ozone standard in the DFW 

nonattainment area. The EPA approved this revision to the SIP for the DFW ozone 

nonattainment area to re-categorize a local ESL control measure as a TCM effective on March 

10, 2014.

1.2.2.2 Reclassification to Serious for the 1997 Eight-Hour Ozone Standard

The nine-county DFW 1997 eight-hour ozone nonattainment area is currently classified as 

serious nonattainment. In 2009, the monitored design value (complete ozone season prior to 

the attainment date) for the nine-county DFW nonattainment area was 86 ppb. Effective 

January 19, 2011, the EPA finalized a determination that the DFW nonattainment area did not 

attain the 1997 eight-hour ozone standard by June 15, 2010, the deadline set by the Phase I 

implementation guidance for the 1997 ozone standard for areas classified as moderate (75 FR 

79302). Based on that determination, the EPA reclassified the DFW nonattainment area to 

serious and set a January 19, 2012 deadline for the state to submit an AD SIP revision that 

addressed the 1997 eight-hour ozone standard serious nonattainment area requirements, 

including RFP. The nine-county DFW nonattainment area’s new attainment date for the 1997 

eight-hour ozone standard was June 15, 2013 which required that only data through 2012 could 

be used to determine attainment under the EPA’s rules.

As required by the FCAA, the TCEQ published a notice in the Texas Register (35 TexReg 4268), 

on May 21, 2010, implementing the area’s contingency measures for failure to attain the 1997 

eight-hour ozone standard by the June 15, 2010 deadline.

Concurrent with the 2011 AD SIP revision, the commission adopted revised and new RACT 

requirements to address the following Control Techniques Guidelines (CTG) documents issued 

by the EPA from 2006 through 2008 (Rule Project Number 2010-016-115-EN): Flexible Package 

Printing; Industrial Cleaning Solvents; Large Appliance Coatings; Metal Furniture Coatings; 

Paper, Film, and Foil Coatings; Miscellaneous Industrial Adhesives; Miscellaneous Metal and 

Plastic Parts Coatings; and Auto and Light-Duty Truck Assembly Coatings. Concurrent with this 

AD SIP revision, the commission also adopted revised and new RACT requirements for VOC 

storage tanks (Rule Project Number 2010-025-115-EN).

This 2011 AD SIP revision included an MVEB for 2012 that represented the on-road mobile 

source emissions that were modeled for the AD. The DFW area's metropolitan planning 

organization must demonstrate that the estimated emissions from transportation plans, 

programs, and projects do not exceed the MVEB. Additionally, this 2011 AD SIP revision showed

that by 2012, the DFW nonattainment area would meet other serious nonattainment area 

requirements, including an enhanced Inspection and Maintenance Program (which had already 

been implemented in all nine counties), Stage II vapor recovery systems at gas stations (which 

had already been implemented in Collin, Dallas, Denton, and Tarrant Counties), a Clean Fuel 

Fleet Program (which is not required if emissions reductions from the National Low-Emissions 
Page 8

Vehicle Program are more than what would be achieved under such a program), TCMs (which 

have already been implemented in all nine counties), and enhanced monitoring.

The EPA published final approval of the 2011 DFW RFP SIP revision on November 12, 2014 (79 

FR 67068); however, the EPA is scheduled to finalize disapproval of portions of the 2011 DFW 

1997 Eight-Hour Ozone AD SIP Revision and to finalize the clean data determination by August 

31, 2015 (80 FR 23487). This redesignation substitute SIP revision is intended to satisfy the 

anti-backsliding obligations for the revoked one-hour and the revoked 1997 eight-hour ozone 

NAAQS by ensuring that the EPA’s requirements for the redesignation of revoked ozone 

standards are met for the DFW ozone nonattainment area. A revised attainment demonstration 

for the 1997 eight-hour ozone standard will not be required with the finalization of the EPA’s 

clean data determination. Further, this redesignation substitute includes emissions inventory 

projections which demonstrate that the DFW area will maintain design values below the 1997 

eight-hour ozone NAAQS through 2028. 

SECTION 2: AIR QUALITY DATA

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

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

The Dallas-Fort Worth (DFW) nonattainment area monitoring network in 2015 consists of 17 

regulatory ambient air ozone monitors located in Collin, Dallas, Denton, Ellis, Johnson, 

Kaufman, Parker, Rockwall and Tarrant Counties, Texas. The City of Dallas operates four of the 

monitors: Dallas Hinton (C0060/C0161/C0401/C3002), Dallas Redbird Airport (C402); Dallas 

North No.2 (C0063/C0679); and Rockwall Health (C0069). The City of Fort Worth operates 

four of the monitors: Parker County (C0076); Eagle Mountain Lake (C0075); Keller (C0017); 

and Arlington Municipal Airport (C0061). The Texas Commission on Environmental Quality 

(TCEQ) operates the remaining 9 ozone monitors: Denton Airport South 

(C0056/C0157/C0163); Pilot Point (C1032); Midlothian OFW (C0052/C0137); Italy (C1044); 

Cleburne Airport (C0077/C0682); Kaufman (C0071); Ft. Worth Northwest (C0013); Grapevine 

Fairway (C0070/C0182); and Frisco (C0031/C0680).

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

verify the attainment status of the area. The Texas Commission on Environmental Quality 

(TCEQ) commits to keep in operation an appropriate air monitoring network in the DFW 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 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) and reported to the EPA on the schedule required by 40 

CFR Part 58.

2.1 Ozone Data

This section provides an analysis of air quality observational data in the DFW four-county and 

nine-county nonattainment areas. While the one-hour and 1997 eight-hour ozone NAAQS is 

expressed in units of parts per million (ppm), the familiar convention of expressing 

concentrations in parts per billion (ppb) is also used in this section. Data for ozone and nitrogen 

oxides (NOX) were downloaded from the EPA’s Air Quality System (AQS) database, and volatile 

organic compounds (VOC) data were downloaded from TCEQ’s automated gas chromatograph 

(auto-GC) database. Analyses of ozone data from federal reference method monitors and federal 
Page 9

equivalent method monitors, those used by the EPA to compare to the NAAQS, are included in 

this section.

2.2 Ozone Trend Analysis

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

improving air quality. The trends in design values for the one-hour and eight-hour ozone 

NAAQS in the DFW nonattainment areas are seen clearly in Figure 2-1: One-Hour Ozone Design 

Values for the DFW Area and Figure 2.2: Eight-Hour Ozone Design Values for the DFW Area.

Regarding the one-hour ozone NAAQS the area monitored attainment of 0.12 ppm (or 124 ppb)

in 2006 and has since remained in attainment of the standard. . The one-hour ozone design 

value for 2014 was 102 ppb. The design value for one-hour ozone standard is the 4th highest 

value, provided that the monitor has three years of completed data. Data has to meet the validity 

checks of at least eighteen valid hours of data to be declared as valid days, at least 75% of days 

with data to be valid months, at least two months of data for valid quarters and at least three 

quarters of data to be declared as a valid year. If one year out of the three year span does not 

meet the completeness requirements, then the design value will be the 3rd highest value of the 

three year span. In 2006, the DFW area measured attainment of the one-hour ozone NAAQS. 

The one-hour ozone design value in the DFW area has shown large decreases over the past 

eleven years, since 2004. The one-hour ozone design value in 2014 was 102 ppb, which 

represents a 27% decrease from the 1990 design value of 140 ppb.

The DFW nine-county area exceeded the 1997 eight-hour ozone NAAQS at the end of 2013, but 

monitored 3 ppb less than the value of the 1997 eight-hour 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, as discussed above. In 2014, the 

DFW area was in attainment of the 1997 eight-hour ozone NAAQS. The eight-hour ozone design 

value in the DFW area has decreased nearly 23% over the past 24 years, from a design value of 

105 ppb in 1990 to a design value of 81 ppb in 2014.
Page 10

Figure 2-1: One-Hour Ozone Design Values for the DFW Area
Page 11

Figure 2-2: Eight-Hour Ozone Design Values for the DFW 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: One-Hour Ozone Design Values by 

Monitor contains one-hour ozone design values at all regulatory monitors in the DFW area from 

2000 through 2014. Since 2006, there have been no monitors in the DFW area that exceeded 

the one-hour ozone standard. Table 2-2: Eight-Hour Ozone Design Values by Monitor contains

eight-hour ozone design values at all regulatory monitors in the DFW area from 2000 through

2014. More monitors than those listed in Table 2-1 and Table 2-2 operate in the DFW area, but 

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

determinations with the DFW nonattainment area because they are not located geographically 

within the area. Only monitors located within the designated nonattainment area are displayed 

in Table 2-1 and Table 2-2. Note that the total number of monitors at the bottom of each table is 

different because there are different counties designated as nonattainment for the one-hour 

ozone NAAQS and the 1997 eight-hour ozone NAAQS. The total number of monitors also 

includes monitors that may not have a valid design value for that year.
Page 12

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

Site Name

200020012002200320042005200620072008200920102011201220132014

Frisco C31 130 130 119 113 113 113 113 111 110 102 102 108 108 108 100

Anna C68 105 105 108 105 103

Dallas 

Hinton St. 

C401/C60/C

127 125 118 125 118 115 114 114 97 87 89 98 101 101 101

Dallas 

North No.2 

C63

128 128 118 113 118 120 117 116 101 105 105 107 106 106 99

Dallas 

Redbird 

Airport 

C402

118 111 103 112 121 121 111 110 109 105 106 105 105 99 96

Sunnyvale 

Long Creek 

C74

89 104 107 107 111 110

Denton 

Airport 

South C56

126 126 128 122 118 117 118 118 118 115 102 109 108 108 99

Pilot Point 107 104 94 97 103 103 103 97

Eagle 

Mountain 

Lake C75

137 135 135 129 125 124 124 115 111 110 108 100 98 94

Ft. Worth 

Northwest 

C13

131 130 126 126 123 123 117 118 109 102 106 106 101 100 100

Keller C17 128 128 128 128 126 117 115 117 111 108 107 110 108 107 95

Grapevine 

Fairway 

C70

122 130 128 125 113 112 111 107 108 104 105 104 104 101

Arlington 

Municipal 

Airport

122 120 120 117 113 113 101 100 97 100 102 102 102

Total 

Number of 

Regulatory 

Monitors

14 13 13 13 12 12 13 12 12 11 11 11 11 11 11

Total 

Number of 

Monitors 

Above 

NAAQS

7 8 5 5 3 1 0 0 0 0 0 0 0 0 0
Page 13

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

Site Name

200020012002200320042005200620072008200920102011201220132014

Frisco C31 101 99 93 88 89 91 92 88 83 79 77 81 83 84 78

Anna C68 76 83 80 80

Dallas 

Hinton St. 

C401/C60/

C

93 92 91 90 89 90 87 84 74 73 82 84 78

Dallas 

North No.2 

C63

93 89 86 87 90 89 86 80 81 78 82 81 83 77

Dallas 

Redbird 

Airport 

C402

88 84 84 85 87 88 88 85 82 78 78 79 81 80 73

Sunnyvale 

Long Creek 

C74

83 83 84

Denton 

Airport 

South C56

102 101 99 97 96 93 95 94 91 85 80 83 83 87 81

Pilot Point 81 77 78 82 82 84 79

Midlothian 

Tower 

C94/C158

97 88 86 82 87 84 83 78

Midlothian 

OFW 

C52/C137

75 73 72 74 76 77 71

Italy C1044 68 69 69 72 67

Cleburne 

Airport C77 89 90 90 89 87 85 83 83 80 79 79 79 76

Kaufman 

C71 73 73 73 75 76 73 70 67 68 70 74 70

Parker 

County C76 86 89 86 87 88 91 84 81 75 79 78 79 74
Page 14

Site Name

200020012002200320042005200620072008200920102011201220132014

Rockwall 

Heath C69 83 81 82 81 80 78 75 75 74 77 77 77 73

Arlington 

Reg. Office 

C57

95 86

Eagle 

Mountain 

Lake C75

95 96 94 95 96 95 89 86 85 83 82 81 79

Ft. Worth 

Northwest 

C13

99 97 96 96 94 95 94 91 83 79 79 82 80 81 80

Keller C17 97 97 98 100 98 95 94 92 87 86 86 90 87 85 77

Grapevine 

Fairway 

C70

95 100 98 93 93 92 87 84 82 86 86 86 80

Arlington 

Municipal 

Airport

87 87 87 84 79 77 79 79 83 80 75

Total 

Number of 

Regulatory 

Monitors

19 18 18 18 17 17 19 19 19 17 17 17 17 17 17

Total 

Number of 

Monitors 

Above 

NAAQS

8 8 11 11 13 12 12 10 4 3 2 2 2 3 0

Figure 2-3: One-Hour Ozone Design Value Statistics for All Monitors in the DFW Area displays 

the statistically summarized maximum, median, and minimum one-hour ozone design values 

computed across all monitors in the DFW area as well as how these distributions changed over 

time. The figure exhibits no noticeable trend until 2000 when the trend begins to fall steadily. 

Before 2000, only two monitors in the DFW area met the one-hour ozone standard; since then, 

the area has seen a steady increase in the number of monitors attaining the standard. By 2014, 

all monitors in the DFW area were below the one-hour ozone NAAQS of 124 ppb.

Figure 2-4: Eight-Hour Ozone Design Value Statistics for All Monitors in the DFW Area shows 

the eight-hour ozone design value exhibited a fairly consistent downward trend since 2000. 

Before 2014, the DFW area had not met the 1997 eight-hour ozone NAAQS of 84 ppb. In 2014 

however, the area monitored attainment of the standard with a design value of 81 ppb.
Page 15

Figure 2-3: One-Hour Ozone Design Value Statistics for All Monitors in the DFW

Area
Page 16

Figure 2-4: Eight-Hour Ozone Design Value Statistics for All Monitors in the DFW

Area

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

of days where the daily one-hour ozone maximum concentration was greater than 124 ppb in a 

year and 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 exceedance days analysis 

demonstrates both that the area remains in attainment, in addition to the distribution of 

exceedances over time, which provides evidence that existing control strategies for ozone are 

effective. Figure 2 5: Number of One-Hour Ozone Exceedance Days by Monitor in the DFW 

Area shows the number of days where one-hour ozone was greater than 124 ppb by year for each 

currently operating DFW monitor from 1990 through 2014. The number of days is the total 

number of unique days (a day with more than one monitor over 124 ppb is only counted once) 

on which any monitor in the DFW area registered a daily peak one-hour ozone concentration

greater than 124 ppb. In 2014, there were zero days that the one-hour ozone concentration was 

greater than 124 ppb. Since 1990, the number of days with ozone concentrations above 124 ppb 

has decreased, which is especially pronounced from 1995 through 2008. The number of days 

with ozone concentrations above 124 ppb occurring in the DFW area fell 100% from seven days 

in 1990 to zero days in 2014. In the last seven years, only one day had ozone concentrations 

above the 124 ppb NAAQS threshold. This means that high ozone days are not only decreasing 

in frequency but they are also decreasing geographically across the entire region, showing an 

area wide trend for the one-hour ozone NAAQS.
Page 17

Figure 2-6: Number of Eight-Hour Ozone Exceedance Days by Monitor in the DFW Area shows 

the number of days where the eight-hour ozone was greater than 84 ppb by year for each 

currently operating DFW monitor from 1990 through 2014. The number of days is the total 

number of unique days on which any monitor in the DFW area registered a daily peak eighthour ozone concentration greater than 84 ppb. In 2014, there were three days that the eighthour ozone concentration was greater than 84 ppb. Since 1990, the number of days with ozone 

concentrations above 84 ppb has decreased, which is especially pronounced from 2005 through 

2010, then again from 2011 through 2014. The number of days with ozone concentrations above 

84 ppb occurring in the DFW area has fallen nearly 91% from 32 days in 1990 to three days in 

2014.

Figure 2-5: Number of One-Hour Ozone Exceedance Days by Monitor in the DFW 

Area
Page 18

Figure 2-6: Number of Eight-Hour Ozone Exceedance Days by Monitor in the DFW 

Area

2.3 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 reductions are due to NOX and VOC emission reductions in the 

DFW 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 DFW area are plotted in Figure 2-7: Annual Maxima, 90th Percentile and 

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

a logarithmic scale so that all three statistics are visible and a linear regression line was added to 
Page 19

each statistic. The linear regression line of the yearly maximum shows a negative slope of 10.6 

ppb per year with an r2 of 0.43, and the regression line of the yearly 90th percentile shows a 

negative slope of 5.1 ppb per year with an r2 of 0.90. The linear regression line of the yearly 

average shows a negative slope of 2.4 ppb per year with an r2 of 0.93. All three measures have 

decreased over the 2000 through 2014 period, falling 32% (maximum), 60% (90th percentile), 

and 61.5% (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 

DFW area and would be expected to support declining ozone values, as observed in the DFW 

area.

Figure 2-7: Annual Maxima, 90th Percentile and Average of Daily Peak NOX Values 

(ppb) in the DFW Area, 2000 through 2014

The other major class of ozone precursors is VOC. Since the mid-1990s, the TCEQ has collected 

40-minute time-integrated measurements in the DFW area, on an hourly basis, of over 40 VOC 

compounds using auto-GC instruments. This section will focus on two prevalent VOC 

compounds that are associated with rapid and efficient ozone formation, ethylene and 

propylene. 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, that is, when the data are not symmetrically, or normally, 

distributed, but instead clustered around extreme high or low values. It is more robust than an 

ordinary average, meaning its value is not greatly influenced by one or a few very high or very 
Page 20

low values. Many distributions of pollutant measurements, especially VOC, in the DFW area are 

skewed, thus the geometric mean was evaluated to provide an assessment of VOC emissions in 

the DFW area.

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

shown in Figure 2-8: Yearly Geometric Mean Ethylene Concentrations (ppbC) at Nine DFW

Monitors, 2000 through 2014. Prior to 2010, only two of the nine monitors had enough valid 

data to calculate annual geometric mean ethylene. . Values for ethylene are fairly low; the 

highest geometric mean ethylene in the DFW area in 2014 was below 0.6 ppbC. While trends are 

generally variable from year to year, the geometric mean ethylene has decreased at the two 

monitors with the longest record of auto-GC data. Ethylene at the Flower Mound Shiloh (C1007) 

monitor had been steadily increasing until 2013, when the geometric mean ethylene decreased 

in 2014. Concentrations at the Arlington UT Campus (C1018), Eagle Mountain Lake (C0075) 

and Kennedale Treepoint Drive (C1062) monitors saw increases between 2013 and 2014, 

although the Arlington UT Campus (C1018) and Kennedale Treepoint Drive (C1062) monitors 

only have two years of valid data to calculate the geometric mean.

Figure 2-8: Yearly Geometric Mean Ethylene Concentrations (ppbC) at Nine DFW 

Monitors, 2000 through 2014

Figure 2-9: Yearly Geometric Mean Propylene Concentrations (ppbC) at Nine DFW Monitors, 

2000 through 2014 shows the annual geometric mean for propylene. Like ethylene, prior to 

2004 only three of the nine monitors had enough valid data to calculate annual geometric mean 
Page 21

propylene. Note that the y-axis is the same as in Figure 2-8. The geometric means for propylene 

are even lower than the geometric means for ethylene for most of the years, with the highest 

geometric mean propylene concentration in the DFW area in 2014 below 0.4 ppbC. All monitors 

have been showing a steady decrease in geometric mean propylene from 2000 through 2014.

The Fort Worth Northwest (C0013) monitor saw a slight increase in propylene measurements 

between 2013 and 2014. Though decreasing at different rates, these long-term decreases in 

ambient concentrations of ethylene and propylene suggest overall industrial and automobile 

emissions of these compounds have decreased considerably since 2000.

Figure 2-9: Yearly Geometric Mean Propylene Concentrations (ppbC) at Nine DFW 

Monitors, 2000 through 2014

2.4 Ozone Data Summary

Ozone concentrations have decreased dramatically in the DFW area since the 1990s. In 2008, 

the one-hour design value dipped below the standard of 0.12 ppm (or 124 ppb); since 2008, only 

one day monitored a one-hour ozone concentration greater than 124 ppb. In 2014, the eighthour ozone design value met the 1997 eight-hour ozone NAAQS of 84 ppb. Examination of the 

number of days that one-hour ozone concentrations exceeded 0.124 ppm and that eight-hour 

ozone concentrations exceeded 0.084 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 DFW area are primarily due to NOX

and VOC reductions in the DFW area, the emission reduction control strategies are effective, 

and that projections for future attainment status are well-founded.
Page 22

SECTION 3: PERMANENT AND ENFORCEABLE EMISSIONS REDUCTIONS

3.1 Control Measures

The Dallas-Fort Worth (DFW) nonattainment area for the one-hour National Ambient Air 

Quality Standard (NAAQS), which consists of Collin, Dallas, Denton, and Tarrant Counties and 

for the 1997 eight-hour ozone NAAQS, which consists of Collin, Dallas, Denton, Ellis, Johnson, 

Kaufman, Parker, and Rockwall, and Tarrant Counties, include a wide variety of major and 

minor industrial, commercial, and institutional entities. The Texas Commission on 

Environmental Quality (TCEQ) has implemented stringent and innovative regulations that 

address emissions of nitrogen oxides (NOX) and volatile organic compounds (VOC) from these 

sources.

3.2 List of Existing Control Measures

Since the early 1990s, a broad range of control measures have been implemented for each 

emission source category for ozone planning in the DFW area. Table 3-1: Existing Ozone Control 

Measures Applicable to the DFW Nonattainment Area lists the existing ozone control strategies 

that have been implemented for the one-hour and 1997 eight-hour ozone NAAQS in the DFW 

areas.

Table 3-1: Existing Ozone Control Measures Applicable to the DFW 

Nonattainment Area

Measure Description Start Date(s)

DFW Industrial, 

Commercial, and 

Institutional (ICI) 

Major Source Rule

30 Texas 

Administrative Code 

(TAC) Chapter 117, 

Subchapter B, Division 

4

Applies to major sources (50 tons per 

year (tpy) of nitrogen oxides (NOX) or 

more) with affected units in Collin, 

Dallas, Denton, Ellis, Johnson, Kaufman, 

Parker, Rockwall, and Tarrant Counties

Applies to major sources (100 tpy of NOx 

or more) with affected units in Wise 

County

Affected source categories included in 

rule: boilers; process heaters; stationary 

gas turbines, and duct burners used in 

turbine exhaust ducts; lime kilns; heat 

treat and reheat metallurgical furnaces; 

stationary internal combustion engines; 

incinerators; glass, fiberglass, and 

mineral wool melting furnaces; fiberglass 

and mineral wool curing ovens; natural 

gas-fired ovens and heaters; brick and 

ceramic kilns; lead smelting 

reverberatory and blast furnaces; natural 

gas-fired dryers used in organic solvent, 

printing ink, clay, brick, ceramic tile, 

calcining, and vitrifying processes; and 

wood-fired boilers

March 1, 2009 or March 1, 

2010, depending on source 

category

Note: these NOX control 

requirements are in addition to 

the NOX control strategies 

previously implemented for ICI 

major sources in Collin, Dallas, 

Denton, and Tarrant Counties 

in March 2002 for the one-hour 

ozone National Ambient Air 

Quality Standards (NAAQS)

January 1, 2017 for Wise 

County and wood-fired boilers 

in all ten counties of the DFW 

area
Page 23

Measure Description Start Date(s)

DFW ICI Minor Source 

Rule

30 TAC Chapter 117, 

Subchapter D, Division 

2

Applies to all minor sources (less than 50 

tpy of NOX) with stationary internal 

combustion engines in Collin, Dallas, 

Denton, Ellis, Johnson, Kaufman, Parker, 

Rockwall, and Tarrant Counties

March 1, 2009 for rich-burn 

gas-fired engines, diesel-fired 

engines, and dual-fuel engines

March 1, 2010 for lean-burn 

gas-fired engines

Stationary Diesel 

Engines

30 TAC Chapter 117, 

Subchapter B, Division 

4 and Subchapter D, 

Division 2 and 

Subchapter C, Division 

4

Prohibition on operating stationary diesel 

and dual-fuel engines for testing and 

maintenance purposes between 6:00 

a.m. and noon in Collin, Dallas, Denton, 

Ellis, Johnson, Kaufman, Parker, Rockwall, 

and Tarrant Counties

April 1, 2009

DFW Major Utility 

Electric Generation 

Source Rule

30 TAC Chapter 117, 

Subchapter C, Division 

4

NOX control requirements for major 

source (50 tpy of NOx or more) utility 

electric generating facilities in Collin, 

Dallas, Denton, Ellis, Johnson, Kaufman, 

Parker, Rockwall, and Tarrant Counties

NOx control requirements for major 

source (100 tpy of NOx or more) utility 

electric generating facilities in Wise 

County

Applies to utility boilers, auxiliary steam 

boilers, stationary gas turbines, and duct 

burners used in turbine exhaust ducts 

used in electric power generating 

systems

Note: these NOX control requirements 

are in addition to the NOX control 

strategies implemented for utilities in 

Collin, Dallas, Denton, and Tarrant 

Counties in 2001 through 2005 for the 

one-hour ozone NAAQS

March 1, 2009 for Collin, Dallas, 

Denton, Ellis, Johnson, 

Kaufman, Parker, Rockwall, and 

Tarrant Counties

January 1, 2017 for Wise 

County

Utility Electric 

Generation in East and 

Central Texas

30 TAC Chapter 117, 

Subchapter E, Division 

1

NOX control requirements on utility 

boilers and stationary gas turbines 

(including duct burners used in turbine 

exhaust ducts) at utility electric 

generation sites in East and Central 

Texas, including Parker County

May 1, 2003 through May 1, 

2005
Page 24

Measure Description Start Date(s)

DFW Cement Kiln Rule

30 TAC Chapter 117, 

Subchapter E, Division 

2

NOX control requirements for all Portland 

cement kilns located in Ellis County

March 1, 2009

NOX Emission 

Standards for Nitric 

Acid Manufacturing –

General

30 TAC Chapter 117, 

Subchapter F, Division 

3

NOX emission standards for nitric acid 

manufacturing facilities (state-wide rule –

no nitric acid facilities in DFW)

November 15, 1999

East Texas Combustion 

Sources

30 TAC Chapter 117, 

Subchapter E, Division 

4

NOX control requirements for stationary 

rich-burn, gas-fired internal combustion 

engines (240 horsepower and greater)

Measure implemented to reduce ozone 

in DFW area although controls not 

applicable in DFW area

March 1, 2010

Natural Gas-Fired 

Small Boilers, Process 

Heaters, and Water 

Heaters

30 TAC Chapter 117, 

Subchapter E, Division 

3

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

May 11, 2000

Offset Lithographic 

Printing

30 TAC, Chapter 115, 

Subchapter E, Division 

4

Control technology requirements for 

offset lithographic printing

Revision to limit Volatile Organic 

Compounds (VOC) content of solvents 

used by offset lithographic printing 

facilities and to include smaller sources in

rule applicability

December 31, 2000 for Collin, 

Dallas, Denton, and Tarrant 

Counties and March 1, 2009 in 

Ellis, Johnson, Kaufman, Parker, 

and Rockwall Counties

March 1, 2011 for major 

printing sources (50 tons of 

VOC per year or more) and 

March 1, 2012 for minor 

printing sources (less than 50 

tons of VOC per year)

VOC Rules – Degassing 

Operations

30 TAC, Chapter 115, 

Subchapter F, Division 

3

VOC control requirements for degassing 

during, or in preparation of, cleaning any 

storage tanks and transport vessels

May 21, 2011 for Collin, Dallas, 

Denton, and Tarrant Counties
Page 25

Measure Description Start Date(s)

VOC Control Measures 

– Storage Tanks

30 TAC Chapter 115, 

Subchapter B, Division 

1

Applies to major source storage tanks (50 

tpy of VOC or more) in Collin, Dallas, 

Denton, Ellis, Johnson, Kaufman, Parker, 

Rockwall, and Tarrant Counties

Applies to major source storage tanks 

(100 tpy of VOC or more) in Wise County

Requires controls for slotted guidepoles 

and more stringent controls for other 

fittings on floating roof tanks, and control 

requirements or operational limitations 

on landing floating roof tanks

Eliminates exemption for storage tanks 

for crude oil or natural gas condensate 

and regulates flash emissions from these 

tanks

New inspection requirements to control 

flashed gases from storage tanks and 

corresponding recordkeeping 

requirements for fixed roof storage tanks

March 1, 2013

January 1, 2017 for major 

source storage tanks in Wise 

County and for new inspection 

requirements to control flashed 

gases from storage tanks and 

corresponding recordkeeping 

requirements for fixed roof 

storage tanks in Collin, Dallas, 

Denton, Ellis, Johnson, 

Kaufman, Parker, Rockwall, 

Tarrant and Wise Counties

VOC Control Measures 

– Solvent-Using 

Processes

30 TAC Chapter 115, 

Subchapter E

Revised rules to implement RACT 

requirements per Control Techniques 

Guidelines issued by the United States 

Environmental Protection Agency (EPA) 

including new control, testing, 

monitoring and recordkeeping 

requirements for eight emission source 

categories in the DFW area: paper, film, 

and foil coatings; large appliance 

coatings; metal furniture coatings; 

miscellaneous metal and plastic parts 

coatings; automobile and light-duty truck 

coating; industrial cleaning solvents; 

miscellaneous industrial adhesives; and 

flexible package printing (see DFW AD SIP 

Revision for the 1997 Eight-Hour Ozone 

Standard Nonattainment Area (2010-

022-SIP-NR))

March 1, 2013 for Collin, Dallas, 

Denton, Ellis, Johnson, 

Kaufman, Parker, Rockwall, and 

Tarrant Counties

January 1, 2017 for Wise 

County
Page 26

Measure Description Start Date(s)

Refueling – Stage I

30 TAC, Chapter 115, 

Subchapter C, Division 

2

Captures gasoline vapors that are 

released when gasoline is delivered to a 

storage tank

Vapors returned to tank truck as storage 

tank is filled with fuel, rather than 

released into ambient air

1990 for Collin, Dallas, Denton, 

Ellis, Johnson, Kaufman, Parker, 

Rockwall, and Tarrant Counties

January 1, 2017 for Wise 

County

A SIP revision related to Stage I 

regulations was approved by 

the EPA, effective June 29, 

2015

Refueling – Stage II

30 TAC, Chapter 115, 

Subchapter C, Division 

4

Captures gasoline vapors when vehicle is 

fueled at pump

Vapors returned through pump hose to 

petroleum storage tank, rather than 

released into ambient air

1992 (Collin, Dallas, Denton, 

and Tarrant Counties)

A SIP revision authorizing the 

decommissioning of Stage II 

vapor control equipment was 

approved by the EPA on March 

17, 2014. Facilities may 

continue operating Stage II 

until August 31, 2018

VOC Control Measures 

30 TAC Chapter 115 

Control technology requirements for VOC 

sources for reasonably available control 

technology (RACT) and other SIP planning 

purposes including: storage, general vent 

gas, industrial wastewater, loading and 

unloading operations, general VOC leak 

detection and repair, solvent using 

processes, etc.

December 31, 2002 and earlier 

for Collin, Dallas, Denton, and 

Tarrant Counties

June 15, 2007 or March 1, 2009 

for Ellis, Johnson, Kaufman, 

Parker, and Rockwall Counties

January 1, 2017 for Wise 

County
Page 27

Measure Description Start Date(s)

Texas Emissions 

Reduction Plan (TERP)

30 TAC Chapter 114, 

Subchapter K

Provides grant funds for on-road and 

non-road heavy-duty diesel engine 

replacement/retrofit. The first emissions 

reduction incentive grant projects funded 

under TERP were for fiscal years 2002 -

2003 (September 1, 2001, through

August 31, 2003). To focus the emissions 

reduction benefits for the areas that 

needed them the most, applications 

were accepted only for projects in the 

Houston-Galveston-Brazoria (HGB) and 

DFW nonattainment areas for fiscal years 

2002 through 2003. An application 

period limited to the DFW, HGB, and 

Beaumont-Port Arthur areas was done in 

2006 and 2007. The allocation approach 

established by the commission for TERP 

included several grant programs for 

reducing emissions from mobile sources 

and encouraging the use of cleaner 

alternative fuels for transportation, 

including the Diesel Emissions Reduction 

Incentive Program providing grants to 

replace or upgrade heavy-duty on-road 

vehicles, non-road equipment, 

locomotives, marine vessels, and some 

stationary engines.

January 2002

Texas Low Emission 

Diesel 

30 TAC Chapter 114, 

Subchapter H, Division 

2

Requires all diesel fuel for both on-road 

and non-road use to have a lower 

aromatic content and a higher cetane 

number

Phased in from October 31, 

2005 through January 31, 2006

Texas Low Reid Vapor 

Pressure (RVP) 

Gasoline

30 TAC Chapter 114, 

Subchapter H, Division 

1

Requires all gasoline for both on-road 

and non-road use to have RVP of 7.8 

pounds per square inch or less from May 

1 through October 1 each year

April 2000 in Ellis, Johnson, 

Kaufman, Parker, Rockwall, and 

Wise Counties
Page 28

Measure Description Start Date(s)

Vehicle Inspection/ 

Maintenance (I/M)

30 TAC Chapter 114, 

Subchapter C

Yearly treadmill-type testing for pre-1996 

vehicles and computer checks for 1996 

and newer vehicles

May 1, 2002 in Collin, Dallas, 

Denton, and Tarrant Counties

May 1, 2003 in Ellis, Johnson, 

Kaufman, Parker, and Rockwall 

Counties

The DFW area meets the FCAA, 

§182(b)(4) requirements to 

implement an Inspection and 

Maintenance (I/M) program , 

and according to 40 CFR 

§51.350(b)(2), an I/M program 

is required to cover the entire 

urbanized area based on the 

1990 census. The current I/M 

program in the DFW ozone 

nonattainment area sufficiently 

covers a population equal to 

the DFW urbanized area, thus 

expansion of the I/M program 

to include Wise County is not 

required.

California Gasoline 

Engines

California standards for non-road 

gasoline engines 25 horsepower and 

larger

May 1, 2004

Transportation Control 

Measures

Various measures in North Central Texas 

Council of Governments’ (NCTCOG) longrange transportation plans

2007

Voluntary Energy 

Efficiency/Renewable 

Energy (EE/RE)

See Chapter 3.3.3: Energy Efficiency and 

Renewable Energy Measures

See Chapter 3.3.3

Voluntary Mobile 

Emissions Reduction 

Program 

Various pedestrian, bicycle, traffic, and 

mass transit voluntary measures 

administered by NCTCOG 

2007

Federal On-Road 

Measures

Series of emissions limits implemented 

by the EPA for on-road vehicles

Included in measures: Tier 1, Tier 2, and 

Tier 3 light-duty and medium-duty 

passenger vehicle standards, heavy-duty 

vehicle standards, low sulfur diesel 

standards, National Low Emission Vehicle 

standards, and reformulated gasoline

Phase in through 2010

Tier 3 phase in from 2017 

through 2025
Page 29

Measure Description Start Date(s)

Federal Area/NonRoad MeasuresSeries of emissions limits implemented 

by the EPA for area and non-road sources

Examples: diesel and gasoline engine 

standards for locomotives and leafblowers

Phase in through 2018

3.2.1 Tier 3 Motor Vehicle Emission and Gasoline Sulfur Standards

On April 28, 2014, the United States Environmental Protection Agency (EPA) finalized the 

Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel 

Standards (79 Federal Register 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.

Tier 3 motor vehicle emission standards of Tier 3 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.

3.3 Additional Measures

3.3.1 SmartWay Transport Partnership and 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.
Page 30

There are over 3,000 SmartWay partners in the United States (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 atmosphere2. 

Approximately 170 Texas companies are SmartWay partners. The SmartWay Transport 

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

and 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 Cement Kiln Consent Decree

Cement kilns located in Ellis County are subject to the requirements of Chapter 117, Subchapter 

E, Division 2. Ash Grove Cement Company operated three kilns in Ellis County, with an 

established source cap under §117.3123 of 4.4 tons per day (tpd).

However, a 2013 consent decree between Ash Grove and the EPA required by September 10, 

2014 shutdown of two kilns and reconstruction of kiln #3 with selective noncatalytic reduction 

(SNCR) with an emission limit of 1.5 pounds of NOx per ton of clinker (lbs NOX/ton) and a 12-

month rolling tonnage limit for NOx of 975 tpy. The reconstructed kiln is a dry kiln with yearround SNCR operation. The redesign allows 949,000 tpy of clinker, or 1.95 tpd of NOX, which is 

well below the 4.4 tpd source cap. Any modifications or new construction would be required to 

meet nonattainment new source review with best available control technology requirements, 

and would be subject to the same 1.5 lbs NOX/ton of clinker emission limit in the New Source 

Performance Standards for Portland Cement Plants.

3.3.3 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 renewable energy include wind energy and solar energy projects.

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

megawatts (MW) of installed wind generation capacity3; 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 

 

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

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

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

http://apps2.eere.energy.gov/wind/windexchange/wind_installed_capacity.asp
Page 31

39 million megawatt-hours (MWh)4, approximately 22% of the total wind net electrical 

generation for the U.S.

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

explicitly included in photochemical modeling for state implementation plan (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 area 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

 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)

 

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

http://www.eia.gov/electricity/data/eia923/
Page 32

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

3.3.3.1 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, 2001, 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 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 which 

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.

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.
Page 33

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, modifies 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.

3.3.3.2 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, update 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.

3.3.3.3 Federal Facility EE/RE 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.

3.3.3.4 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, nonbuilding lighting projects, and other mechanical and electrical systems retrofits such as 

municipal water and waste water treatment systems.

3.3.3.5 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 
Page 34

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.

3.3.3.6 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.

3.3.4 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 incorporates 

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.

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 must 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 
Page 35

in another state. CAIR consists of two phases for implementing necessary NOX and SO2

reductions. Phase I addresses required reductions from 2009 through 2014. Phase II addresses 

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, Regular Session.

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 

the 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, which 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.

3.3.5 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 

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 $4.5 million being used for 833 school buses in the DFW area.
Page 36

3.3.6 Texas Emission Reduction Plan 

The Texas Emissions Reduction Plan (TERP) was created in 2001 by the 77th Texas Legislature, 

Regular Session, 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 $313 million in DERI grants were awarded 

to projects in the DFW area, with a projected 57,052 tons of NOX reduced. These projects were

estimated to reduce up to 18.3 tons per day of NOX in the DFW area in 2015. The emissions 

reduction estimates will change yearly as older projects reach the end of the project life and new 

projects begin achieving emissions reductions. Also, of that $313 million awarded in the DFW 

area, $22 million were awarded to North Central Texas Council of Governments through thirdparty grants to administer subgrants in the DFW area.

An additional 666 DERI grants were selected for funding in FY 2015 for $80.6 million. Ninetyone of these projects were in the DFW area and totaled approximately $9.1 million. Subject to 

final contracting, these projects are estimated to reduce approximately 986 tons of NOX in the 

DFW area, representing almost 0.6 tons per day of NOX reduced beginning in 2017.

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

emissions in the DFW area as discussed below.

A new Drayage Truck Incentive Program was established in 2013 to provide grants for the 

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

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 25 tons in the DFW area. This 

represents an additional 0.02 tpd of NOX projected to be reduced in the DFW 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. Over $3.3 million in TCFP 

grants were awarded to projects in the DFW area, with a projected 89.4 tons of NOX reduced. 

The projects are estimated to reduce over 0.07 tpd of NOX in the DFW area starting in 2015. The 

latest TCFP grant application period ended October 3, 2014, with five projects totaling $8.85 

million selected for funding. Subject to final contracting, these projects are estimated to result in 

an additional 124 tons of NOX reduced, including 94 tons in the DFW area. This represents an 

additional 0.076 tpd of NOX projected to be reduced in the DFW area beginning in 2017.
Page 37

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 $13.2 million in TNGVGP grants were awarded to projects 

where the applicant indicated the primary operation of the vehicle would occur in and around 

the DFW area, with a projected 452 tons of NOX reductions. These projects are estimated to 

reduce up to 0.36 tpd of NOX in the DFW area starting in 2015.

An additional 53 projects for approximately $15.8 million were selected for funding in FY 2015.

Twenty-four of these grants totaling $7.1 million are for projects with primary operation in the 

DFW area. The estimated emissions reductions from the FY 2015 projects will be available once 

final contracts are completed and calculations are performed. 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 for future 

grant projects that should result in NOX reductions in the eligible TERP areas, including the 

DFW area.

3.3.7 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, higer 

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, Regular Session, 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 program and have elected to implement 

LIRAP fee provisions. The counties currently participating in the LIRAP are Brazoria, Fort 

Bend, Galveston, Harris, Montgomery, Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, 

Rockwall, Tarrant, Travis, and Williamson Counties.

SB 12, 80th Texas Legislature 2007, Regular Session, expanded the 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 28,604 vehicles in the DFW area at a cost of $85,903,000. 

During the same period, an additional 16,635 vehicles in the DFW area have had emissionsrelated repairs at a cost of $8,318,866. The total retirement/replacement and repair expenditure 

for the DFW area from December 12, 2007 through May 31, 2015 is $94,221,866.
Page 38

HB 1, General Appropriations Bill, 84th Texas Legislature, 2015, Regular Session, appropriated 

$43.5 million per year for FYs 2016 and 2017 to continue this clean air strategy in the 16 

participating counties. The nine counties that participate in the program in the DFW area, 

Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant, were allocated 

approximately $21.6 million per year for the LIRAP for FYs 2016 and 2017. This is an increase of 

approximately $18.8 million per year over the previous biennium.

3.3.8 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 DFW area, Local Initiative 

Projects (LIP) funding is available to the nine counties currently participating in the LIRAP: 

Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant. HB 1, General 

Appropriations Bill, 84th Texas Legislature 2015, Regular Session, appropriated $4.8 million 

per year for FYs 2016 and 2017 to continue this clean air strategy. The nine DFW area counties 

were allocated approximately $2.4 million per year for FYs 2016 and 2017. This is an increase of 

approximately $2.1 million per year over the previous biennium.

Dallas County used LIP funds in 2008 to establish the Dallas County Clean Air Emissions Task 

Force. For its first seven years, the task force 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.

Following the success of Dallas County’s emissions enforcement project, Denton (2009-2015), 

Ellis (2008-2014), Johnson (2010-2014), Kaufman (2012-2015), and Tarrant (2010-2015) 

Counties established similar task forces. Beginning in March 2015, the emission enforcement 

task forces adjusted their objectives to concentrate on the identification of vehicles with 

counterfeit registration insignia and the reduction of fraudulent vehicle inspection reports. 

These programs have partnered with local and state agencies to enforce state laws, codes, rules, 

and regulations regarding air quality and mobile emissions in the DFW area. The citizens of the 

entire north Texas region benefit from these programs as a result of the reduction in NOX

emissions from each vehicle brought into emissions compliance.

The City of Plano, through Interlocal Agreements with Collin County, used LIP funding in 2012 

and 2014 for Local Initiative Projects. In 2012, LIP funding was used by the City of Plano to 

install auxiliary power units in police department vehicles to reduce vehicle emissions during 

the daily activities of traffic enforcement. This idle reduction technology powers equipment such 

as lights, radio, and computers so that law enforcement officers can shut-off their vehicles to 

perform traffic control, traffic accident investigations, lunch breaks, and other activities where 

the enforcement officer is outside their vehicle. In 2014, the City of Plano used LIP funding to 

install wireless communications technology at 20 intersections and additional pan/tilt cameras 

at 19 of those intersections. The project allows signal management from a traffic management 

center to reduce traffic congestion and idling in an effort to reduce emissions. The project 

reduces idling by improving traffic flow and decreasing the number of times vehicles must stop 

at traffic lights. The exhaust phase of an engine emits the most emissions during starting, idling, 

and breaking stationary inertia. The project increases the emissions reduction benefits by 

allowing real-time traffic management instead of a stagnate model to better manage peak-hour 

congestion, while minimizing cross-traffic congestion, and reducing emissions.
Page 39

3.3.9 84th Texas Legislature 

Bills passed during the 84th Texas Legislature, 2015, that have the potential to impact the DFW 

area are discussed in Section 3.3.3: Energy Efficiency and Renewable Energy Measures and 

Section 3.3.7: Low Income Vehicle Repair Assistance, Retrofit, and Accelerated Vehicle 

Retirement Program. As discussed in Section 3.3.7, HB1 appropriated $43.5 million per year for 

FYs 2016 and 2017 to continue this clean air strategy in the 16 participating counties. The nine 

counties that participate in the program in the DFW area, Collin, Dallas, Denton, Ellis, Johnson, 

Kaufman, Parker, Rockwall, and Tarrant, were allocated approximately $21.6 million per year 

for the LIRAP for FYs 2016 and 2017. This is an increase of approximately $18.8 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 DFW area. These 

enforceable measures will remain in place to ensure continued maintenance of the one-hour and 

the 1997 eight-hour ozone NAAQS in the DFW areas. 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 DFW area. Implementation of these control measures will contribute 

to the continued maintenance of the one-hour and the 1997 eight-hour ozone NAAQS. The 

TCEQ continues to seek innovative air quality improvement measures and technologies to 

implement in the DFW area.

SECTION 4: MAINTENANCE DEMONSTRATION

4.1 General

This redesignation substitute (RS) state implementation plan (SIP) revision is intended to 

demonstrate that the Dallas-Fort Worth (DFW) area will remain in attainment of the one-hour 

and 1997 eight-hour ozone National Ambient Air Quality Standards (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 RS SIP revision proposal, the TCEQ was developing the 2014 periodic emissions inventory 

for the DFW 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 RS SIP revision 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 EI for the DFW four-county one-hour and nine-county 1997 eight-hour 

ozone nonattainment areas showed a significant decrease in ozone precursor emissions from all 

source categories as detailed in Section 4.2: Historical Emissions Inventory Trends, which 

contributed to the attainment of the one-hour and 1997 eight-hour ozone NAAQS. These 
Page 40

reductions were accomplished through a variety of federal, state, and local regulations and 

programs as detailed below.

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 DFW four-county and nine-county nonattainment areas 

declined substantially as a result of regulations implemented at the federal, state, and local 

levels and innovative programs implemented by the TCEQ. In the DFW four-county one-hour 

ozone nonattainment area from 2002 through 2011, anthropogenic volatile organic compounds 

(VOC) emissions have decreased 12%, and anthropogenic nitrogen oxides (NOX) emissions have 

decreased 36%. In the DFW nine-county 1997 eight-hour ozone nonattainment area from 2002 

to 2011, anthropogenic VOC emissions have decreased 8%, and anthropogenic NOX emissions 

have decreased 37%.These trends are detailed in:

 Figure 4-1: DFW Four-County Nonattainment Area Historical NOX Emissions Trends,

 Figure 4-2: DFW Nine-County Nonattainment Area Historical NOX Emissions Trends,

 Figure 4-3: DFW Four-County Nonattainment Area Historical VOC Emissions Trends, and

 Figure 4-4: DFW Nine-County Nonattainment Area Historical VOC Emissions Trends.

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 have significantly reduced overall ozone precursor emissions at both 

major and minor (point and area) industrial, commercial, and institutional sources in the DFW 

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 DFW area.
Page 41

Figure 4-1: DFW Four-County Nonattainment Area Historical NOX Emissions 

Trends

Figure 4-2: DFW Nine-County Nonattainment Area Historical NOX Emissions 

Trends

34.57

7.94 10.4

8.38 22.44

36.60

74.81

31.06

345.10

313.70

225.53

191.55

104.08 110.58 115.19

93.26

0

50

100

150

200

250

300

350

400

2002 2005 2008 2011

Point

Area

On-Road

Non-road

Emissions in Tons Per Day

79.23

56.93

49.12

31.34

118.97 130.03

141.87

112.40

23.69 47.52

147.25

37.69

428.49

385.57

270.60 230.09

0

100

200

300

400

500

0

20

40

60

80

100

120

140

160

180

200

2002 2005 2008 2011

Point

Nonroad

Area

OnRoad

Emissions in Tons Per Day
Page 42

Figure 4-3: DFW Four-County Nonattainment Area Historical VOC Emissions 

Trends

Figure 4-4: DFW Nine-County Nonattainment Area Historical VOC Emissions 

Trends

18.76 21.42 19.01 16.15

197.27 202.36

250.92

216.47

118.39

102.95

91.73

70.11 76.71

59.57 62.11

47.54

0

50

100

150

200

250

300

2002 2005 2008 2011

Point

Area

On-Road

Non-road

Emissions in Tons Per Day

26.44 29.58 31.27 27.65

228.97 235.16

304.67

262.35

136.86

117.76

103.83

87.43 78.62

67.19 70.23

53.76

0

50

100

150

200

250

300

350

2002 2005 2008 2011

Point

Area

On-Road

Non-road

Emissions in Tons Per Day
Page 43

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 DFW 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 DFW one-hour and 1997 eight-hour ozone nonattainment areas

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 EIs for the four one-hour 

and nine 1997 eight-hour ozone nonattainment counties in the DFW area are 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 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 DFW area toward continued attainment of the one-hour and 1997 eighthour ozone NAAQS, the TCEQ will continue to develop and submit periodic EIs (PEI) 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 

DFW 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 Federal Register 

12264), states can rely on periodic AERR EI submittals to satisfy ongoing SIP EI submission 

requirements every three years.

Because the EPA has not made guidance available for how to demonstrate continued attainment 

in a redesignation substitute, the TCEQ is using the method outlined in the EPA’s redesignation 

guidance5. Future emissions for the DFW 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 

 

5 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 44

is satisfied when the state demonstrates that future VOC and NOX emissions levels are not 

expected to result in exceedances of the one-hour and 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: Emissions Summary.

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.

4.4.1.1 Updated 2012 Base Year Inventories

The updated 2012 base year inventory was formed using 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: Projection Factors for Point and Area Sources.

In particular, the TCEQ focused on refining 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 
Page 45

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 emissions

factors for VOC emissions from condensate storage tanks. The documentation for the refined 

emissions 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 emissions 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.

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 most area source categories were developed using factors derived from

Attachment A: Projection Factors for Point and Areas Sources, 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.

For DFW counties with oil and gas production that reside in the Barnett Shale area, specifically 

Dallas, Denton, Ellis, Johnson, Parker, and Tarrant Counties, growth factors from the report in 

Attachment E: Forecasting Oil and Gas Activities, were used. These ERG-derived factors deal 

specifically with oil and gas sources in the Barnett Shale area and employ category-oriented 

growth factors for each forecasting year.

The updated milestone year area source emissions inventories were developed by applying the 

selected growth factors to the baseline emissions for each area source category to account for 

any growth in emissions. Rules controlling emissions from industrial coatings, portable fuel 

containers, 30 TAC Chapter 117 Subchapter D controls on minor sources in ozone 

nonattainment areas, and gasoline station underground tank filling (Stage I) and vehicle 

refueling (Stage II) were accounted for in the base year inventory.

In addition, New Source Performance Standard (NSPS) OOOO controls on upstream oil and gas 

sources became fully applicable after the 2012 base year. Therefore, these controls were not 

incorporated in the base year inventory. Additionally, the NSPS OOOO controls were not 

incorporated into the milestone year inventories because they are not needed to demonstrate 

maintenance. 
Page 46

4.4.1.3 Area Source Emissions Inventories

The DFW area source base year (2012), milestone years (2014, 2017, 2020, 2023, and 2026) and 

horizon year (2028) EIs for NOX and VOC for the two DFW ozone nonattainment areas are 

summarized in the following tables:

 Table 4-1: DFW Area Source Four-County One-Hour Ozone Nonattainment Area NOX and 

VOC Emissions (tons per day), and

 Table 4-2: DFW Area Source Nine-County 1997 Eight-Hour Ozone Nonattainment Area

NOX and VOC Emissions (tons per day).

Table 4-1: DFW Area Source Four-County One-Hour Ozone Nonattainment Area

NOX and VOC Emissions (tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 28.54 29.41 27.79 25.96 24.90 24.68 24.68

VOC 218.90 224.51 218.56 211.43 209.81 210.69 211.77

Table 4-2: DFW Area Source Nine-County 1997 Eight-Hour Ozone Nonattainment 

Area NOX and VOC Emissions (tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 33.60 34.77 32.01 28.98 27.37 26.97 26.93

VOC 265.43 273.08 260.19 245.76 241.13 241.19 242.15

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 (TDM), 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 DFW one-hour and 1997 eight-hour ozone 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 
Page 47

October 7, 2014 (70 FR 60343); and released an update to the model on October 27, 2014. The 

TCEQ, working with the North Central Texas Council of Governments (NCTCOG), recently 

completed MOVES2014-based 2012, 2014, 2017, 2020, 2023, 2026, and 2028 on-road emission 

inventories for the DFW 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 are developed.

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 DFW 

one-hour and 1997 eight-hour ozone RS report were developed by the NCTCOG using the latest 

available data, current emissions factors and models, and the most current planning 

assumptions. The inventories include the four DFW-area counties designated as nonattainment 

for the one-hour ozone NAAQS and the nine DFW-area counties designated as nonattainment 

for the 1997 eight-hour ozone NAAQS. 

Consistent with on-road inventory development procedures for reporting requirements and 

reasonable further progress demonstration state implementation plans, 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. 

The roadway link-level VMT estimates were obtained from travel demand modeling for each of 

the DFW counties for each analysis year. Two methods are used to establish VMT: a federal 

system, the Highway Performance Monitoring System (HPMS); and a local system, a travel 

demand model (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. A summary of the on-road mobile source 

VMT used to develop the various NOX and VOC emissions estimates for the four-county one-
Page 48

hour and the nine-county 1997 eight-hour ozone nonattainment areas are presented separately 

in the following tables:

 Table 4-3: DFW Four-County One-Hour Ozone Nonattainment Area VMT (miles per 

average summer day), and

 Table 4-4: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area VMT (miles per 

average summer day).

Table 4-3: DFW Four-County One-Hour Ozone Nonattainment Area VMT (miles 

per average summer day)

Table 4-4: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area VMT 

(miles per average summer day)

Year Vehicle Miles Traveled

2012 183,855,804

2014 193,671,709

2017 212,516,292

2020 226,113,715

2023 238,584,779

2026 251,758,922

2028 265,309,733

The on-road mobile source 2012, 2014, 2017, 2020, 2023, 2026, and 2028 EIs for NOX and VOC 

for the DFW nonattainment areas are summarized in the following tables:

 Table 4-5: DFW Four-County One-Hour Ozone Nonattainment Area Average Summer 

Weekday NOX and VOC Emissions for On-Road Mobile Sources (tons per day), and

 Table 4-6: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area 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 the DFW 

one-hour and 1997 eight-hour ozone nonattainment areas RS SIP revision, including the 

inventory development methods, MOVES inputs, and the results, refer to Appendix F:

Development of DFW On-Road Emission 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.

Year Vehicle Miles Traveled

2012 158,968,136

2014 166,904,345

2017 182,658,562

2020 193,804,121

2023 203,852,679

2026 214,346,979

2028 225,718,496
Page 49

Table 4-5: DFW Four-County One-Hour Ozone Nonattainment Area Average 

Summer Weekday NOX and VOC Emissions for On-Road Mobile Sources (tons per 

day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 171.20 147.42 96.74 69.67 54.44 43.33 38.83

VOC 78.56 71.20 55.59 46.81 41.53 35.85 32.94

Table 4-6: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area 

Average Summer Weekday NOX and VOC Emissions for On-Road Mobile Sources 

(tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 216.74 188.65 129.19 95.95 77.87 64.62 59.75

VOC 92.17 83.75 65.62 55.36 49.21 42.70 39.49

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 one-hour and 

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, the National Low Emission 

Vehicle (NLEV) program, summer reformulated gasoline (RFG), the Texas Regional Low RVP, 

the DFW vehicle inspection and maintenance (I/M) program, the DFW anti-tampering 

program, and Texas Low Emission Diesel (TxLED). The federal RFG program was implemented 

in the four DFW one-hour counties. The Texas Regional Low RVP Program does not include 

RFG counties and is modeled only for Ellis, Johnson, Kaufman, Parker, and Rockwall Counties. 

The DFW I/M program began in 1990 in Dallas and Tarrant counties; was expanded in 2002 

and 2003 to include additional counties; and now includes all nine DFW one-hour and 1997 

eight-hour ozone nonattainment counties. A summary of the DFW on-road mobile source 

control strategies used for this DFW one-hour and 1997 eight-hour ozone RS report are 

presented in Table 4-7: DFW On-Road Mobile Control Strategies Summary.

Table 4-7: DFW 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 (psi)

Included for 2012, 2014, 2017, 2020, 2023, 2026, 

and 2028

Tier 1 FMVCP 1994 Included for 2012, 2014, 2017, 2020, 2023, 2026,

and 2028
Page 50

Control Program 

Description

Year Control 

Program Started Control Scenario Notes

RFG Phase 1 1995 for Phase 1 Collin, Dallas, Denton, and Tarrant Counties

Superseded by RFG Phase 2

I/M Program 1990 thru 2003 Dallas and Tarrant Counties (1990); Collin and 

Denton Counties added (2002); Ellis, Johnson, 

Kaufman, Parker, and Rockwall Counties added

(2003)

RFG Phase 2 2000 for Phase 2 Collin, Dallas, Denton, and Tarrant Counties

Included for 2012, 2014, 2017, 2020, 2023, 2026,

and 2028

Texas Regional Low RVP 2000 Ellis, Johnson, Kaufman, Parker, and Rockwall 

Counties

Maximum summertime RVP of 7.8 psi

NLEV Program 2001 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 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 gasoline sulfur

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, 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 in VMT for all milestone years, for 

both the one-hour and 1997 eight-hour ozone nonattainment county groups. A summary of the 
Page 51

tons per day (tpd) change from the 2012 base year to each milestone year and the horizon year 

are summarized in the following tables:

 Table 4-8: DFW Four-County One-Hour Ozone Nonattainment Area Estimated On-road 

Mobile Sources Reductions from 2012 Baseline Due to FMVCP, I/M, RFG, and TxLED (tons 

per day), and

 Table 4-9: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area Estimated Onroad Mobile Sources 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 the following tables:

 Table 4-10: DFW Four-County One-Hour Ozone Nonattainment Area Estimated Percent 

On-road Mobile Sources Reductions from 2012 Baseline Due to FMVCP, I/M, RFG, and 

TxLED, and 

 Table 4-11: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area Estimated 

Percent On-road Mobile Sources Reductions from 2012 Baseline Due to FMVCP, I/M, RFG, 

and TxLED.

Table 4-8: DFW Four-County One-Hour Ozone Nonattainment Area Estimated 

On-road Mobile Sources Reductions from 2012 Baseline1 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 -23.78 -7.36

2017 -74.46 -22.97

2020 -101.53 -31.75

2023 -116.76 -37.03

2026 -127.87 -42.71

2028 -132.37 -45.62

Note 1: The four county 2012 on-road emissions levels from which the reductions are taken are: 171.20 

tpd NOX and 78.56 tpd VOC (see Table 4-5)
Page 52

Table 4-9: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area

Estimated On-road Mobile Sources Reductions from 2012 Baseline2 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 -28.09 -8.42

2017 -87.55 -26.55

2020 -120.79 -36.81

2023 -138.87 -42.96

2026 -152.12 -49.47

2028 -156.99 -52.68

Note 2: The nine county 2012 on-road emissions levels from which the reductions are taken are: 216.74 

tpd NOX and 92.17 tpd VOC (see Table 4-6)

Table 4-10: DFW Four-County One-Hour Ozone Nonattainment Area Estimated 

Percent On-road Mobile Sources Reductions from 2012 Baseline3 Due to FMVCP, 

I/M, RFG, and TxLED

Inventory Year NOX% Reductions VOC % Reductions

2012 0 0

2014 -13.9 -9.4

2017 -43.5 -29.2

2020 -59.3 -40.4

2023 -68.2 -47.1

2026 -74.7 -54.4

2028 -77.3 -58.1

Note 3: The four county 2012 on-road emissions levels from which the percent reductions are taken are: 

171.20 tpd NOX and 78.56 tpd VOC (see Table 4-5)

Table 4-11: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area

Estimated Percent On-road Mobile Sources Reductions from 2012 Baseline4 Due 

to FMVCP, I/M, RFG, and TxLED

Inventory Year NOX% Reductions VOC% Reductions

2012 0 0

2014 -13 -9.1

2017 -40.4 -28.8

2020 -55.7 -39.9

2023 -64.1 -46.6

2026 -70.2 -53.7

2028 -72.4 -57.2

Note 4: The nine county 2012 on-road emissions levels from which the percent reductions are taken are: 

216.74 tpd NOX and 92.17 tpd VOC (see Table 4-6)
Page 53

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. Note CMV activities do not apply to the DFW area; 

therefore all counties in the DFW area will indicate zero emissions for CMV activities. The 

following sections describe the emissions calculation methods used for the non-road mobile 

source subcategories.

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, 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 NONROAD2008a model. Documentation of 

methods and procedures used in developing NONROAD model category EIs can be found in 

Attachment G: 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 emissions 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 DFW area airport EIs can be found in Attachment H: 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 I: 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.
Page 54

The 2012 inventory for the 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 

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. 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 

using the most recent version of the TexN 2008a model (version 1.7). The TexN model runs 

were performed by ERG for the analyses years 2012, 2014, 2017, 2020, 2023, 2026, and 2028 to

estimate the average summer weekday emissions for the NONROAD model categories. For more 

details, please see Attachment G: Development of Air Emissions Inventories for Non-Road 

Model Category Mobile Sources (Task3). 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 with new growth factors such as those available on the Economic and 

Consumer Credit Analytics website (https://www.economy.com) to support more accurate 

forecasting and back-casting of emissions.

The updated milestone year inventories for the following source categories were developed 

based on studies found in the appendices listed below.

 NONROAD model category mobile sources inventories were based on the ERG study found 

in Attachment G: Development of Air Emissions Inventories for Non-Road Model Category 

Mobile Sources (Task3),

 airport source inventories were based on the ERG study found in Attachment H: Airport 

Emissions Inventories for Houston-Galveston-Brazoria and Dallas-Fort Worth Areas for 

Select Years 2012, 2014, 2017, 2020, 2023, 2026, and 2028,

 locomotive inventories were based on the ERG study found in Attachment I: Controlled and 

Uncontrolled Average Summer Weekday Locomotive Inventories for Houston-GalvestonBrazoria and Dallas-Fort Worth Areas for Select Years 2012, 2014, 2017, 2020, 2023, 

2026, and 2028 , and

 drilling rig inventories were based on the ERG study found in Attachment J: Development of 

Texas Statewide Drilling Rigs Emission Inventories for the Years 1990, 1993, 1996, and 

1999 through 2040.

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: Development of Texas Statewide Drilling Rigs Emission Inventories for the 

Years 1990, 1993, 1996, and 1999 through 2040 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: Projection 

Factors for Point and Area Sources.
Page 55

4.4.3.3 Non-Road Mobile Source Emissions Inventories

The non-road mobile source NOX and VOC emissions for the 2012 through 2028 milestone 

years for the DFW area are presented in:

 Table 4-12: DFW Four-County One-Hour Ozone Nonattainment Area NOX Emissions for 

Non-Road EI Categories (tons per day),

 Table 4-13: DFW Four-County One-Hour Ozone Nonattainment Area VOC Emissions for 

Non-Road EI Categories (tons per day),

 Table 4-14: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area NOX Emissions 

for Non-Road EI Categories (tons per day), and

 Table 4-15: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area VOC Emissions 

for Non-Road EI Categories (tons per day).

Please note that although drilling rig VOC emissions for 2026 and 2028 are shown as 0.00 tons 

per day in Tables 4-13 and 4-15, there are actually small amounts of drilling rig VOC emissions 

forecasted for these two years. These emissions are below 0.005 tons per day for each of the 

forecasted years, so the values round downwards to zero.

Table 4-12: DFW Four-County One-Hour Ozone Nonattainment Area NOX

Emissions for Non-Road EI Categories (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Airport 10.12 11.28 12.34 13.31 14.19 15.24 16.07

Commercial Marine Vessels 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Drilling Rigs 3.75 4.08 2.56 1.00 0.32 0.10 0.04

Locomotive 10.33 10.12 8.89 8.21 7.45 6.33 5.71

NONROAD Model Categories 52.75 46.81 37.77 30.79 26.91 24.69 23.84

Non-road Total 76.95 72.29 61.56 53.31 48.87 46.36 45.66

Table 4-13: DFW Four-County One-Hour Ozone Nonattainment Area VOC 

Emissions for Non-Road EI Categories (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Airport 2.95 3.14 3.41 3.64 3.85 4.09 4.28

Commercial Marine Vessels 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Drilling Rigs 0.18 0.19 0.12 0.05 0.02 0.00 0.00

Locomotive 0.60 0.56 0.46 0.40 0.36 0.30 0.27

NONROAD Model Categories 37.66 32.59 28.6 26.99 26.81 27.13 27.53

Non-road Total 41.39 36.48 32.59 31.08 31.04 31.52 32.08
Page 56

Table 4-14: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area NOX

Emissions for Non-Road EI Categories (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Airport 10.15 11.31 12.37 13.34 14.22 15.28 16.11

Commercial Marine Vessels 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Drilling Rigs 4.97 5.40 3.40 1.33 0.43 0.13 0.06

Locomotive 14.36 14.04 12.24 11.25 10.16 8.61 7.74

NONROAD Model Categories 63.50 56.08 44.82 36.18 31.40 28.69 27.64

Non-road Total 92.98 86.83 72.83 62.10 56.21 52.71 51.55

Table 4-15: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area VOC 

Emissions for Non-Road EI Categories (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Airport 3.02 3.22 3.49 3.72 3.92 4.17 4.36

Commercial Marine Vessels 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Drilling Rigs 0.24 0.26 0.16 0.06 0.02 0.01 0.00

Locomotive 0.83 0.76 0.61 0.53 0.47 0.40 0.35

NONROAD Model Categories 42.78 37.10 32.47 30.47 30.14 30.42 30.82

Non-road Total 46.87 41.34 36.73 34.78 34.55 35.00 35.53

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 DFW ozone nonattainment area. 

Therefore, some minor sources in the DFW ozone nonattainment area report to the point source 

EI.

To collect the data, the TCEQ sends notices to 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 major 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 June 5, 2014. The 

extracted data included reported annual and ozone season daily emissions of NOX and VOC for 
Page 57

each site in the DFW area for which a 2012 EIQ was submitted and reflected revisions made on 

or before the extract date.

4.4.4.3 Updated Milestone Year Inventories

The TCEQ designated the 2013 EI as the starting point for emissions inventory projections for 

each of the milestone years because it was the most recent point source 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 March 4, 2015. The extracted 

data included reported annual and ozone season daily emissions of NOX and VOC for each site in 

the DFW 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 NOX or VOC.

NOX emissions from electric generating units (EGU) and cement kilns were projected separately 

from other sources. EGU emissions were projected using Cross State Air Pollution Rule (CSAPR) 

allocations. Ozone season allocations were averaged over the 153 day season to obtain milestone 

year projections for 2017 and beyond. No CSAPR allocations were available for 2014 so EGU 

emissions for 2014 were projected using growth factors; the projected values for NOX emissions 

were within 0.01 tons per day (tpd) of NOX emissions reported to the EPA’s Clean Air Markets 

Division under the Acid Rain Program. Emissions from other non-CSAPR units at EGU sites 

were projected using growth factors. Cement kiln emissions for 2017 and beyond were projected 

using the 30 TAC Chapter 117 cap, which limits future emissions growth to the cap levels. The 30 

TAC Chapter 117 cap provides a conservative estimate of emissions growth.

Other major source emissions were projected by adding emissions growth allowed under the 

major modification thresholds. Specifically, NOX emissions from non-EGU and non-cement 

sites identified as major sources of NOX emissions and VOC emissions from sites identified as 

major sources of VOC emissions were projected using the moderate nonattainment major 

modification threshold of 40 tons per year. The moderate nonattainment threshold was selected 

based upon the DFW area’s classification for the 2008 ozone NAAQS. Title V operating permit 

data from 2014 were reviewed to identify major sources of NOX and VOC emissions. For each 

site identified, a daily average of this growth was calculated by prorating the annual 40-ton 

major modification threshold by the site-wide ratio of ozone season to annual emissions to 

provide a one-time growth limit added to the site’s 2013 emissions. To maintain a conservative 

approach, all growth was taken into account for the 2017 milestone year inventory.

For minor sources, NOX and VOC emissions were projected using emissions trend data and 

growth factors for each milestone year. Emissions 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 were modified so that emissions for these source categories remained equal to the 

2013 baseline inventory through future years.
Page 58

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 

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 for DFW 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 moderate ozone nonattainment areas since the area would be classified as moderate 

nonattainment upon redesignation. Applying the moderate ozone nonattainment offset ratio 

(1.15 to 1) instead of the serious ozone nonattainment offset ratio (1,2 to 1) to unused credits 

conservatively estimates growth: since less credits are needed to offset emissions from new or 

modified sources, the amount of credits available to return to the airshed increases.

All available ERCs listed in the emissions banking and trading database as of January 15, 2015 

were added to each milestone year starting with 2017. This includes transactions with available 

information for the period 2008 to 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 VOC DERC use was determined by assuming that all available credits would be used 

over the 2017 to 2028 timespan. The credits were averaged over the 2017 to 2028 projected 

timespan to obtain a yearly amount. The yearly amount was averaged over the DFW ozone 

season to obtain a daily contribution and added to the projected inventories. The DERC 

transactions between 2008 and 2014 were not applied as they were used for one-time 

compliance projects applicable to, and reflected in, emissions for those years only.

Projected NOX DERC use was determined by using the flow control value of 17.0 tons per day as 

listed in 30 TAC § 101.379 adopted June 3, 2015. This approach is conservative and simplified; 

historical use has been considerably less. The flow control value of 17.0 tpd is added to each of 

the 2017 through 2028 milestone year NOX emissions.

A summary of the point source inventories is presented in the following tables:

 Table 4-16: DFW Four-County One-Hour Ozone Nonattainment Area Point Source NOX

and VOC Emissions (tons per day)

 Table 4-17: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area Point Source 

NOX and VOC Emissions (tons per day)

Table 4-16: DFW Four-County One-Hour Ozone Nonattainment Area Point Source 

NOX and VOC Emissions (tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 8.47 8.79 29.47 29.57 29.65 29.71 29.76

VOC 11.11 11.02 11.52 11.71 11.86 11.99 12.08
Page 59

Table 4-17: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area Point 

Source NOX and VOC Emissions (tons per day)

Pollutant 2012 2014 2017 2020 2023 2026 2028

NOX 30.80 31.25 62.38 62.49 62.57 62.64 62.71

VOC 27.66 28.61 29.46 29.97 30.41 30.82 31.10

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 DFW four one-hour and nine 1997 eight-hour ozone nonattainment 

areas are shown in:

 Table 4-18: DFW Four-County One-Hour Ozone Nonattainment Area NOX Emissions by 

Source Category (tons per day),

 Table 4-19: DFW Four-County One-Hour Ozone Nonattainment Area VOC Emissions by 

Source Category (tons per day),

 Table 4-20: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area NOX

Emissions by Source Category (tons per day), and

 Table 4-21: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area VOC Emissions 

by Source Category (tons per day).

These tables illustrate that in the horizon year of 2028, mobile sources (on-road and non-road) 

contribute the most NOX emissions and area sources contribute the most VOC emissions for 

both the DFW four one-hour and nine 1997 eight-hour ozone nonattainment counties. 

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

limited to anthropogenic sources.

Table 4-18: DFW Four-County One-Hour Ozone Nonattainment Area NOX

Emissions by Source Category (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Point Sources 8.47 8.79 29.47 29.57 29.65 29.71 29.76

Area Sources 28.54 29.41 27.79 25.96 24.90 24.68 24.68

On-Road Mobile Sources 

(MOVES2014)

171.20 147.42 96.74 69.67 54.44 43.33 38.83

Non-Road Mobile Sources 76.95 72.29 61.56 53.31 48.87 46.36 45.66

Total 285.16 257.91 215.56 178.51 157.86 144.08 138.93

Table 4-19: DFW Four-County One-Hour Ozone Nonattainment Area VOC 

Emissions by Source Category (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Point Sources 11.11 11.02 11.52 11.71 11.86 11.99 12.08

Area Sources 218.90 224.51 218.56 211.43 209.81 210.69 211.77

On-Road Mobile Sources 

(MOVES2014)

78.56 71.20 55.59 46.81 41.53 35.85 32.94
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Category 2012 2014 2017 2020 2023 2026 2028

Non-Road Mobile Sources 41.39 36.48 32.59 31.08 31.04 31.52 32.08

Total 349.96 343.21 318.26 301.03 294.24 290.05 288.87

Table 4-20:DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area NOX

Emissions by Source Category (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Point Sources 30.80 31.25 62.38 62.49 62.57 62.64 62.71

Area Sources 33.60 34.77 32.01 28.98 27.37 26.97 26.93

On-Road Mobile Sources 

(MOVES2014)

216.74 188.65 129.19 95.95 77.87 64.62 59.75

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

Total 374.12 341.50 296.41 249.52 224.02 206.94 200.94

Table 4-21: DFW Nine-County 1997 Eight-Hour Ozone Nonattainment Area VOC 

Emissions by Source Category (tons per day)

Category 2012 2014 2017 2020 2023 2026 2028

Point Sources 27.66 28.61 29.46 29.97 30.41 30.82 31.10

Area Sources 265.43 273.08 260.19 245.76 241.13 241.19 242.15

On-Road Mobile Sources 

(MOVES2014)

92.17 83.75 65.62 55.36 49.21 42.70 39.49

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

Total 432.13 426.78 392.00 365.87 355.30 349.71 348.27

4.6 Maintenance Demonstration Conclusion

Future year trends were analyzed using the 2012 base year and the 2028 projected emissions 

above for the DFW four-county one-hour and the nine-county 1997 eight-hour ozone 

nonattainment areas. Trend analysis using the 2028 future year emissions shows an overall 

decrease of 207.32 tpd in combined NOX and VOC emissions for the DFW four-county one-hour 

ozone nonattainment area. This net change for the four-county area includes a projected 61.09

tpd decrease in VOC and a 146.23 tpd decrease in NOX.

For the DFW nine-county 1997 eight-hour ozone nonattainment area, the trend analysis shows 

an overall decrease of 257.04 tpd in combined NOX and VOC emissions. The net change for the 

nine-county area includes a projected 83.86 tpd decrease in VOC and a 173.18 tpd decrease in 

NOX.

Previous photochemical modeling analysis for the DFW area shows that reducing NOX

emissions is expected to be more effective in reducing the one-hour and the 1997 eight-hour 

ozone design values than VOC reductions. Therefore, the projected 146.23 tpd and 173.18 tpd

decreases of NOX are expected to reduce one-hour and 1997 eight-hour ozone design values 

more effectively than the smaller 61.09 tpd and 83.86 tpd decreases in VOC emissions. Based on 
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future expected trends and previous photochemical analysis, the DFW area is projected to show 

continued attainment of the one-hour and 1997 eight-hour ozone NAAQS through 2028.