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Air Pollution from Sulfur Dioxide

General information on sulfur dioxide and associated air quality standards, Texas' compliance status, and latest air quality planning activities.

Many of the SIP files on this page are hosted by the Texas Records and Information Locator (TRAIL) web archiveExit the TCEQ. If you need assistance with a file, please contact siprules@tceq.texas.gov.

What is Sulfur Dioxide?

Sulfur dioxide (SO2) is one of a group of highly reactive gases called sulfur oxides (SOX). Exposure to SO2 can affect the respiratory system, especially for people with asthma. Studies show connections between short-term exposure and increased visits to emergency departments and hospital admissions for respiratory illnesses, particularly in populations at risk (including children, the elderly, and asthmatics). SOX can react with other compounds in the atmosphere to form small particles that cause or worsen respiratory disease or aggravate existing heart disease.

The largest source of SO2 emissions is fossil fuel combustion at power plants and other industrial facilities. SO2 emissions also come from extraction of metal from ore and burning high-sulfur fuels in locomotives, large ships, and non-road equipment.

National Ambient Air Quality Standards (NAAQS) for SO2

The United States Environmental Protection Agency (EPA) issued annual and 24-hour primary (health-based) SO2 standards as well as three-hour and annual secondary SO2 standards in 1971. As a result of the EPA's review of the SO2 NAAQS in 1973, the secondary annual SO2 standard was revoked and the secondary three-hour standard was retained. Following a subsequent review of the NAAQS in 1996, the EPA retained both the annual and 24-hour primary SO2 standards.

2010 SO2 NAAQS Revision

Effective August 23, 2010, the EPA revised the SO2 NAAQS, adding a primary one-hour standard of 75 parts per billion (ppb) (application/pdf75 FR 35520Exit the TCEQ). A one-hour standard was determined to better protect the public from exposure to high short-term SO2 concentrations, especially in communities located close to coal-fired power plants, industrial boilers, petroleum refineries, metal processing plants, and diesel exhausts.

In setting the 2010 primary one-hour SO2 standard, the EPA revoked the annual and 24-hour primary standards for areas not previously designated nonattainment, to become effective one year after designations for the 2010 standard are finalized. For areas of the country previously designated nonattainment for SO2 under the 1971 standards, the annual and 24-hour standards remain in effect until state implementation plans to attain or maintain the 2010 standard are approved by the EPA.

Implementation of the 2010 Primary SO2 NAAQS

For information on the EPA's implementation schedule for the 2010 Primary SO2 NAAQS, please visit the EPA's Primary Sulfur Dioxide NAAQS Implementation ScheduleExit the TCEQ webpage.

Round 1 Designations

In June 2011, Texas application/pdfrecommendedExit the TCEQ to the EPA that Jefferson County be designated as nonattainment for the 2010 SO2 standard; that Dallas, Ellis, El Paso, Galveston, Gregg, Harris, Kaufman, McLennan, and Nueces Counties be designated attainment; and all remaining counties be designated unclassifiable. Texas' recommendation was based on 2009 and preliminary 2010 design values for the state's existing SO2 regulatory monitors.

In April 2012, Texas submitted a application/pdfrevised recommendationExit the TCEQ to the EPA that Dallas, Ellis, El Paso, Galveston, Gregg, Harris, Jefferson, Kaufman, McLennan, and Nueces Counties be designated attainment for the 2010 SO2 standard; and all remaining counties be designated unclassifiable. Texas' revised recommendation was based on 2011 design values for the state's existing SO2 regulatory monitors.

On August 5, 2013, the EPA published final nonattainment area designations for areas with 2009 through 2011 monitoring data indicating violations of the one-hour SO2 standard (application/pdf78 FR 47191Exit the TCEQ). No areas of Texas were designated.

Round 2 Designations

A consent decree to resolve the EPA’s failure to timely promulgate designations was ordered by the U.S. District Court for the Northern District of California on March 3, 2015. The court-ordered settlement established deadlines for the EPA to complete designations in several rounds. Areas with newly monitored violations or large emissions sources not announced for retirement as of March 2015, with 2012 SO2 emissions greater than 16,000 tons per year (tpy) or greater than 2,600 tpy with average emission rate greater than 0.45 pounds per million British thermal units (lbs/MMBtu), were to be designated by the EPA in Round 2 by July 2, 2016.

In a application/pdfletter dated March 20, 2015Exit the TCEQ, the EPA identified 12 electric power plants in Texas with emissions meeting the court-ordered consent decree criteria for designation by July 2016. No monitors with violations of the 2010 primary SO2 NAAQS were identified in Texas. The EPA’s letter provided Texas with an opportunity to revise previously recommended designations, and to submit supporting data and any additional information for EPA consideration, by September 18, 2015. Following the state's September 18, 2015 revised recommendation, the EPA issued a application/pdf120-day noticeExit the TCEQ to Texas on February 11, 2016 with proposed designations for counties surrounding the 12 facilities. The application/pdfstate’s responseExit the TCEQ to the EPA’s 120-day notice was submitted to the EPA on April 19, 2016. On June 30, 2016, application/pdfthe EPA notified the governorExit the TCEQ that it is designating Atascosa, Fort Bend, Goliad, Lamb, Limestone, McLennan, and Robertson Counties as unclassifiable/attainment and Potter County as unclassifiable. Designations were published in the Federal Register on July 12, 2016 with an effective date of September 12, 2016 (application/pdf81 FR 45039Exit the TCEQ). Designations for Freestone, Anderson, Milam, Rusk, Gregg, Panola, and Titus counties were delayed. Final designations for these counties were published on December 13, 2016 (application/pdf81 FR 89870Exit the TCEQ). Nonattainment designations were promulgated for three areas: (1) portions of Freestone and Anderson Counties; (2) portions of Rusk and Panola Counties; and (3) a portion of Titus County (application/pdfmapExit the TCEQ). An unclassifiable designation was promulgated for Milam County.  For more information visit the EPA’s SO2 Designations - Round 2 State Recommendations and EPA ResponsesExit the TCEQ webpage.

Round 2 Area Updates

On August 22, 2019, the EPA proposed an Error Correction of the Area Designations for the 2010 One-Hour SO2 Primary NAAQS in Freestone and Anderson Counties, Rusk and Panola Counties, and Titus County to revise the three nonattainment area designations to unclassifiable designations (application/pdf84 FR 43757Exit the TCEQ). For more information, visit the EPA's Proposed Error Correction of the Designations for Areas in TexasExit the TCEQ webpage.

On June 30, 2020 the TCEQ sent a letter to the EPA application/pdfrequesting a clean data determinationExit the TCEQ for the nonattainment portion of Freestone, Anderson, and Titus Counties designated in Round 2. On September 25, 2020, the EPA published a proposed clean data determination for the 2010 one-hour primary SO2 NAAQS for the Freestone-Anderson and Titus County nonattainment areas (application/pdf85 FR 60407Exit the TCEQ). On May 14, 2021, the EPA published final clean data determinations for the Freestone-Anderson and the Titus Count nonattainment areas (86 FR application/pdf26401Exit the TCEQ).

On August 10, 2020, the EPA published a final action finding that Texas has failed to submit the required SIP revisions for the three Texas SO2 nonattainment areas, effective September 9, 2020 (application/pdf85 FR 48111Exit the TCEQ).

On June 26, 2020, application/pdfthe TCEQ notified the EPA that Milam CountyExit the TCEQ, designated as unclassifiable in Round 2, should be redesignated to attainment. On September 2, 2020, the EPA published a proposal to redesignate Milam County from unclassifiable to attainment/unclassifiable (application/pdf85 FR 54517Exit the TCEQ). On July 16, 2021, the EPA published the final rule redesignating Milam County from unclassifiable to attainment/unclassifiable (application/pdf86 FR 37683Exit the TCEQ).

On October 21, 2020, the commission adopted an agreed order between the TCEQ and Xcel Energy to support attainment and maintenance of the 2010 SO2 NAAQS in Potter County.

The Data Requirements Rule

The EPA’s Data Requirements Rule (DRR) for the 2010 primary one-hour SO2 NAAQS, finalized on August 10, 2015 and published on August 21, 2015 (application/pdf80 FR 51052Exit the TCEQ), provided three options for states to characterize and assess SO2 air quality near sources that emit greater than 2,000 tpy: (a) modeling, (b) monitoring, or (c) enforceable emissions limits (below 2,000 tpy). Areas to be characterized by modeling and other areas without monitors were to be designated by the EPA in Round 3 by December 31, 2017. Areas to be characterized by monitoring as well as any remaining undesignated areas will be designated by the EPA in Round 4 by December 31, 2020.

The DRR required states to identify and submit a list to EPA of all applicable emissions sources by January 15, 2016. The TCEQ identified 25 sources in Texas with emissions greater than 2,000 tpy, and application/pdfnotified the EPA on January 15, 2016Exit the TCEQ. On April 22, 2016, the TCEQ application/pdfrequested revision of the list down to 24 sourcesExit the TCEQ, and the application/pdfEPA concurredExit the TCEQ on May 4, 2016. By July 1, 2016, Texas was required to identify the characterization approach planned for each identified source. For any source to be evaluated with modeling, states must submit a modeling protocol by July 1, 2016, a modeling analysis by January 13, 2017, and annual reports thereafter, to the EPA. On June 29, 2016, the TCEQ submitted an air quality characterization plan and modeling protocol for identified sources.

For more information about the DRR, please visit the EPA's SO2 Data Requirements RuleExit the TCEQ webpage.

Round 3 Designations

Per the DRR, a complete modeling analysis for the Oklaunion Power Station in Wilbarger County was submitted to the EPA on January 12, 2017.

The EPA published final Round 3 area designations for the 2010 SO2 NAAQS on January 9, 2018 (83 FR 1098Exit the TCEQ), designating 238 Texas counties (or portions thereof) as attainment/unclassifiable, including the modeled Wilbarger County. County boundaries define all but four of these areas. In Anderson, Panola, Rusk, and Freestone Counties, the areas designated attainment/unclassifiable are the remaining portions of those counties not previously designated nonattainment in the December 2016 Round 2 designations. Round 3 designations became effective April 9, 2018.

For more information, please visit the EPA's Round 3 SO2 DesignationsExit the TCEQ webpage.

Round 4 Designations

In Round 4, the EPA must designate all remaining areas not yet designated for the 2010 SO2 NAAQS by December 31, 2020. On May 11, 2020, the TCEQ provided application/pdfsupplemental informationExit the TCEQ in support of an attainment/unclassifiable designation for Orange County in Round 4.

On August 13, 2020, the EPA sent a application/pdf120-day letterExit the TCEQ informing Governor Abbott of intended Round 4 area designations. The EPA plans to designate Bexar, Harrison, Jefferson, and Robertson Counties, and the remaining portion of Titus County, as attainment/unclassifiable, Orange County as unclassifiable, and Hutchinson, Howard, and Navarro Counties as nonattainment. On October 16, 2020, Governor Abbott application/pdfsubmitted a responseExit the TCEQ to the EPA's 120-day letter.

On March 26, 2021, the EPA published the final rule designating Bexar, Jefferson, Robertson Counties, and the remainder of Titus County as attainment/unclassifiable, Orange and Harrison Counties as unclassifiable, and portions of Howard, Hutchinson, and Navarro Counties as nonattainment (application/pdf86 FR 16055Exit the TCEQ). The effective date of the designations is April 30, 2021.

For more information on Round 4 designations, please visit the EPA's Sulfur Dioxide Designations - Regulatory Actions - Round 4 Area DesignationsExit the TCEQ webpage.

For a complete timeline of the EPA's designation process, including submittal deadlines per the DRR, see the application/pdfTimeline for the 2010 SO2 NAAQS Designations ProcessExit the TCEQ

Latest Air Quality Planning Activities

Last updated: 9/16/2022

Howard County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS

On October 5, 2022, the commission will consider adoption of the Howard County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS (Project No. 2021-010-SIP-NR). The SIP revision addresses FCAA SIP requirements for the Howard County SO2 nonattainment area by including a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all reasonably available control measures (RACM) and reasonably available control technology (RACT); air quality dispersion modeling to demonstrate attainment; a reasonable further progress demonstration; contingency measures; and certification that nonattainment new source review requirements are met. 

The associated 30 TAC Chapter 112, Subchapter E rulemaking (Rule Project No. 2021-035-112-AI) would provide the enforceable control strategy needed to demonstrate attainment of the 2010 SO2 NAAQS by the April 30, 2026, attainment deadline.

Hutchinson County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS

On October 5, 2022, the commission will consider adoption of the Hutchinson County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS (Project No. 2021-011-SIP-NR). The SIP revision addresses FCAA SIP requirements for the Hutchinson County SO2 nonattainment area by including a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all RACM and RACT; air quality dispersion modeling to demonstrate attainment; a reasonable further progress demonstration; contingency measures; and certification that nonattainment new source review requirements are met.  

The associated 30 TAC Chapter 112, Subchapter F rulemaking (Rule Project No. 2021-035-112-AI) would provide the enforceable control strategy needed to demonstrate attainment of the 2010 SO2 NAAQS by the April 30, 2026 attainment date.

Navarro County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS

On October 5, 2022, the commission will consider adoption of the Navarro County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS (Project No. 2021-012-SIP-NR). The SIP revision addresses FCAA requirements for the Navarro County SO2 nonattainment area by including a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all RACM and RACT; air quality dispersion modeling to demonstrate attainment; a reasonable further progress demonstration; contingency measures; and certification that nonattainment new source review requirements are met.  

The associated 30 TAC Chapter 112, Subchapter G rulemaking (Rule Project No. 2021-035-112-AI) would provide the enforceable control strategy needed to demonstrate attainment of the 2010 SO2 NAAQS by the April 30, 2026 attainment date.

Proposed Howard County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS

On April 13, 2022, the commission approved proposal of the Howard County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS (Project No. 2021-010-SIP-NR). The proposed SIP revision addresses FCAA SIP requirements for the Howard County SO2 nonattainment area by including a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all reasonably available control measures (RACM) and reasonably available control technology (RACT); air quality dispersion modeling to demonstrate attainment; a reasonable further progress demonstration; contingency measures; and certification that nonattainment new source review requirements are met. 

The associated proposed 30 TAC Chapter 112, Subchapter E rulemaking (Rule Project No. 2021-035-112-AI) would provide the enforceable control strategy needed to demonstrate attainment of the 2010 SO2 NAAQS by the April 30, 2026, attainment deadline.

A public comment period will open on April 15, 2022 and close on June 2, 2022. A public hearing on the proposed SIP revision will be held on May 18, 2022 at 6:00 p.m. in the Dora Roberts Community Center Ball Room located at 100 Whipkey Drive in Big Spring, Texas. For more information, please visit the Proposed SIP Revisions and Public Hearing Information section of the Texas SIP Revisions webpage.

Proposed Hutchinson County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS

On April 13, 2022, the commission approved proposal of the Hutchinson County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS (Project No. 2021-011-SIP-NR). The proposed SIP revision addresses FCAA SIP requirements for the Hutchinson County SO2 nonattainment area by including a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all RACM and RACT; air quality dispersion modeling to demonstrate attainment; a reasonable further progress demonstration; contingency measures; and certification that nonattainment new source review requirements are met.  

The associated proposed 30 TAC Chapter 112, Subchapter F rulemaking (Rule Project No. 2021-035-112-AI) would provide the enforceable control strategy needed to demonstrate attainment of the 2010 SO2 NAAQS by the April 30, 2026 attainment date.

A public comment period will open on April 15, 2022 and close on June 2, 2022. A public hearing on the proposed SIP revision will be held on May 19, 2022 at 6:00 p.m. in the Borger City Hall City Council Room at 600 North Main Street in Borger, Texas. The hearing will be conducted in English. Language interpretation services may be requested. For more information, please visit the Proposed SIP Revisions and Public Hearing Information section of the Texas SIP Revisions webpage.

Proposed Navarro County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS

On April 13, 2022, the commission approved proposal of the Navarro County Attainment Demonstration SIP Revision for the 2010 One-Hour SO2 NAAQS (Project No. 2021-012-SIP-NR). The proposed SIP revision addresses FCAA requirements for the Navarro County SO2 nonattainment area by including a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all RACM and RACT; air quality dispersion modeling to demonstrate attainment; a reasonable further progress demonstration; contingency measures; and certification that nonattainment new source review requirements are met.  

The associated proposed 30 TAC Chapter 112, Subchapter G rulemaking (Rule Project No. 2021-035-112-AI) would provide the enforceable control strategy needed to demonstrate attainment of the 2010 SO2 NAAQS by the April 30, 2026 attainment date.

A public comment period will open on April 15, 2022 and close on June 2, 2022. A public hearing on the proposed SIP revision will be held on May 23, 2022 at 6:00 p.m. in the Cook Education Center of Navarro College located at 3100 West Collin Street in Corsicana, Texas. For more information, please visit the Proposed SIP Revisions and Public Hearing Information section of the Texas SIP Revisions webpage.

Redesignation Request and Maintenance Plan SIP Revision for the Freestone-Anderson and Titus 2010 SO2 NAAQS Nonattainment Areas

On February 23, 2022, the commission adopted the Redesignation Request and Maintenance Plan SIP Revision for the Freestone-Anderson and Titus 2010 SO2 NAAQS Nonattainment Areas (Non-Rule Project No. 2021-007-SIP-NR). The SIP revision includes a request that the EPA redesignate the Freestone-Anderson and Titus nonattainment areas to attainment for the 2010 SO2 NAAQS and provides 10-year maintenance plans for both areas consistent with FCAA, §175A requirements. The SIP revision also addresses the comprehensive emissions inventory and nonattainment new source review certification statement SIP requirements provided under Part D of the federal Clean Air Act (FCAA).

Rusk-Panola Attainment Demonstration SIP Revision for the 2010 SO2 NAAQS and Associated Agreed Order

On February 9, 2022, the commission adopted the Rusk-Panola Attainment Demonstration SIP Revision for the 2010 SO2 NAAQS (Non-Rule Project No. 2020-057-SIP-NR) and associated Agreed Order (Non-Rule Project No. 2021-013-OTH-NR) with Luminant Generation Company, LLC (the company). The SIP revision includes a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all RACM and RACT; air quality dispersion modeling to demonstrate attainment of the 2010 SO2 NAAQS; a reasonable further progress demonstration; contingency measures; and certification that nonattainment new source review requirements are met for the Rusk-Panola 2010 SO2 NAAQS nonattainment area.

The Agreed Order provides the enforceable control strategy for the associated attainment demonstration by documenting the commission's order, and the company's agreement, to comply with the requirements identified for the Martin Lake Steam Electric Station, pursuant to the Texas Clean Air Act, the Texas Health & Safety Code, and the FCAA. 

Proposed Rusk-Panola Attainment Demonstration SIP Revision for the 2010 SO2 NAAQS and Associated Agreed Order

On September 8, 2021, the commission approved proposal of the Rusk-Panola Attainment Demonstration SIP Revision for the 2010 SO2 NAAQS (Non-Rule Project No. 2020-057-SIP-NR) and associated proposed Agreed Order (Non-Rule Project No. 2021-013-OTH-NR) with Luminant Generation Company, LLC (the company). The proposed SIP revision includes a comprehensive inventory of current SO2 emissions; evaluation and provision for implementing all RACM and RACT; air quality dispersion modeling to demonstrate attainment of the 2010 SO2 NAAQS; a reasonable further progress demonstration; contingency measures; and certification that nonattainment New Source Review requirements are met for the Rusk-Panola 2010 SO2 NAAQS nonattainment area.

The proposed Agreed Order will provide the enforceable control strategy for the associated proposed attainment demonstration by documenting the commission's order, and the company's agreement, to comply with the requirements identified for the Martin Lake Steam Electric Station, pursuant to the Texas Clean Air Act, the Texas Health & Safety Code, and the FCAA. 

The public comment period will open on September 10, 2021 and close on October 13, 2021. A virtual public hearing on the proposed SIP revision will be held on October 12, 2021 at 2:00 p.m. Central Standard Time. Individuals who plan to attend the public hearing must register by October 5, 2021. For information about how to register, please visit the Proposed SIP Revisions and Public Hearing Section of the Texas SIP Revisions webpage.

Proposed Redesignation Request and Maintenance Plan SIP Revision for the Freestone-Anderson and Titus 2010 SO2 NAAQS Nonattainment Areas

On August 25, 2021, the commission approved proposal of the Redesignation Request and Maintenance Plan SIP Revision for the Freestone-Anderson and Titus 2010 SO2 NAAQS Nonattainment Areas (Non-Rule Project No. 2021-007-SIP-NR). The proposed SIP revision includes a request that the EPA redesignate the Freestone-Anderson and Titus nonattainment areas to attainment for the 2010 SO2 NAAQS and provides 10-year maintenance plans for both areas consistent with FCAA, §175A requirements. The proposed SIP revision also addresses the comprehensive emissions inventory and nonattainment new source review certification statement SIP requirements provided under Part D of the FCAA.

The public comment period will open on August 27, 2021 and close on September 29, 2021. A virtual public hearing on the proposed SIP revision will be held on September 28, 2021 at 2:00 p.m. Central Standard Time. Individuals who plan to attend the public hearing must register by September 21, 2021. For information about how to register, please visit the Proposed SIP Revisions and Public Hearing Section of the Texas SIP Revisions webpage.

SIP Kick-Off for Round 4 SO2 Nonattainment Areas

On March 25, 2021, the TCEQ held an informational meeting for representatives of facilities located in the portions of Howard, Hutchinson, and Navarro Counties that were designated nonattainment by the EPA for the 2010 One-Hour Primary SO2 NAAQS. TCEQ staff gave a presentation providing introductory information about the nonattainment designations, SIP planning requirements, the SIP development process including control strategy development, and anticipated timelines for SIP development.

Xcel Energy Agreed Order

On October 21, 2020 the commission adopted an agreed order between the TCEQ and Xcel Energy to support attainment and maintenance of the 2010 SO2 NAAQS in Potter County, which was designated Unclassifiable in Round 2.

Oklaunion Power Station Modeling Analysis

For any source to be evaluated with modeling, the DRR requires states to submit a modeling analysis by January 13, 2017. A modeling analysis for the Oklaunion Power Station was submitted to the EPA on January 12, 2017.

Air Quality Characterization Plan for Areas with Identified SO2 Sources

The DRR requires air agencies to notify the EPA by July 1, 2016 of the air quality characterization method planned to evaluate areas where identified sources are located. Air agencies were also required to submit revised monitoring network plans and modeling protocols to the EPA by July 1, 2016 to address sources to be evaluated through monitoring and modeling. On June 29, 2016, the TCEQ submitted an air quality characterization plan to evaluate each of the areas where 24 sources were identified in Texas. The plan included reference to the TCEQ's 2016 Air Monitoring Network Plan (submitted separately) and an attached modeling protocol for the Oklaunion Power Station.

SO2 Sources Identified for Further Evaluation Per the Data Requirements Rule

The TCEQ identified 25 sources in Texas with emissions greater than 2,000 tpy, and notified the EPA on January 15, 2016. On April 22, 2016, the TCEQ requested revision of the list down to 24 sources, and the EPA concurred on May 4, 2016.

Revised Designation Recommendations for the 2010 Primary SO2 NAAQS

On September 18, 2015, Texas submitted revised designation recommendations and supporting information to the EPA to address 12 facilities in Texas with SO2 emissions meeting the court-ordered consent decree criteria for designation by July 2, 2016. Texas recommends attainment designations for Dallas, El Paso, Ellis, Galveston, Gregg, Harris, Jefferson, Kaufman, McLennan, Navarro, and Nueces Counties. These 11 counties have certified air monitoring data showing compliance with the 2010 SO2 NAAQS. Texas recommends unclassifiable/attainment designations for the remainder of the state (243 counties).

Infrastructure and Transport SIP Revision for the 2010 SO2 NAAQS

On April 23, 2013, the commission adopted the FCAA, §110(a)(1) and (2) Infrastructure and Transport SIP Revision for the 2010 SO2 NAAQS (Project No. 2012-022-SIP-NR).

The application/pdfSIP revisionExit the TCEQ identifies basic program elements enabling Texas to meet infrastructure requirements for the 2010 SO2 NAAQS, as stipulated in the FCAA. The revision specifically addresses FCAA, §110(a)(2)(D)(i)(I) transport requirements with a technical demonstration showing Texas does not contribute significantly to nonattainment nor interfere with maintenance of the SO2 NAAQS in any other state.

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