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Houston-Galveston-Brazoria: Current Attainment Status

Compliance of HGB-area counties with the National Ambient Air Quality Standards (NAAQS).

Note: This table is intended to provide a listing of designations and classifications for current, active National Ambient Air Quality Standards (NAAQS). While NAAQS which have been revoked by the EPA do not appear in this table, some antibacksliding obligations may continue to apply for revoked standards. This table is to be used for informational purposes only and should not be used to determine regulatory requirements in any of the counties listed.

HGB Area: Attainment Status by Pollutant




Primary NAAQS


Averaging Period






Attainment Deadline


Ozone (O3)*

0.070 ppm (2015 standard) 





0.075 ppm (2008 standard)


Marginal Nonattainment

Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, Waller

July 20, 2015

Lead (Pb)

0.15 µg/m3
(2008 standard)

Rolling 3-Month Average

Unclassifiable/ Attainment



Carbon Monoxide (CO)

9 ppm


Unclassifiable/ Attainment



35 ppm


Unclassifiable/ Attainment



Nitrogen Dioxide (NO2)

0.053 ppm


Unclassifiable/ Attainment



100 ppb


Unclassifiable/ Attainment



Particulate Matter (PM10)

150 µg/m3


Unclassifiable/ Attainment



Particulate Matter (PM2.5)

12.0 µg/m3(2012 standard)

Annual (Arithmetic Mean)

Unclassifiable/ Attainment



15.0 µg/m3(1997 standard)

Annual (Arithmetic Mean)

Unclassifiable/ Attainment



35 µg/m3


Unclassifiable/ Attainment



Sulfur Dioxide (SO2)

0.03 ppm**

Annual (Arithmetic Mean)

Unclassifiable/ Attainment



0.14 ppm**


Unclassifiable/ Attainment



75 ppb


Governor’s Recommendation: Attainment

Galveston, Harris


**The United States Environmental Protection Agency (EPA) revoked the one-hour ozone standard and the 1997 eight-hour ozone standard in all areas, although some areas have continuing obligations under these standards. See ozone history for more information.

**Standard will be revoked one year after the effective date of final designations for the 75 ppb standard.

For more information on attainment status, visit the EPA's Green Book Exit the TCEQ Web page regarding nonattainment areas for criteria pollutants.

HGB Nonattainment Areas

2008 Eight-Hour Ozone Standard Designation: Marginal Nonattainment, effective July 20, 2012 (77 FR 30088) Exit the TCEQ
On March 27, 2008, the EPA lowered the primary and secondary eight-hour ozone NAAQS to 0.075 parts per million (ppm) (73 FR 16436)Exit the TCEQ. An eight-county HGB area including Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller counties was designated “nonattainment” and classified “marginal” under the 2008 eight-hour ozone NAAQS, effective July 20, 2012. The HGB area includes the same eight counties that were designated “nonattainment” under the 1997 eight-hour ozone standard. The attainment deadline for the HGB marginal nonattainment area is July 20, 2015.

Status: On May 4, 2016, the EPA published a final rule in the Federal Register (81 FR 26697) granting a one-year attainment deadline extension for the HGB 2008 eight-hour ozone marginal nonattainment area to July 20, 2016.

1997 Eight-Hour Ozone Standard Designation: Severe Nonattainment, October 1, 2008 (73 FR 56983)Exit the TCEQ
Former 1997 Eight-Hour Ozone Standard Designation: Moderate Nonattainment, April 30, 2004 (69 FR 23858)Exit the TCEQ
An eight-county HGB area was designated “nonattainment” under the 1997 eight-hour ozone NAAQS, and classified as a moderate nonattainment area on April 30, 2004. The counties affected under this designation are Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller. The EPA granted the governor’s request to voluntarily reclassify the HGB ozone nonattainment area from a moderate to a severe nonattainment area for the 1997 eight-hour ozone standard, effective October 31, 2008. The HGB area’s new attainment deadline for the 1997 eight-hour ozone standard is as expeditiously as practicable but no later than June 15, 2019.

Status: Based on data from 2012 through 2014, the HGB area is monitoring attainment of the 1997 eight-hour ozone NAAQS. On February 27, 2015, the TCEQ submitted a request for a finding that the HGB area is attaining the 1997 eight-hour ozone NAAQS.

National Ambient Air Quality Standards

The EPA sets National Ambient Air Quality Standards Exit the TCEQ for six principal criteria pollutants: ground-level ozone, lead, carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter. 

Within one year after promulgation of a new or revised NAAQS for any pollutant, the governor must submit designation recommendations to the EPA for all areas of the state. The EPA must then promulgate the designations within two years of promulgation of the revised NAAQS. Areas that do not meet (or contribute to ambient air quality in a nearby area that does not meet) the NAAQS are designated “nonattainment.” Areas that meet the NAAQS are designated “attainment,” and areas that cannot be classified based on the available information, “unclassifiable.”

For ozone, the federal Clean Air Act establishes nonattainment-area classifications ranked according to the severity of the area’s air-pollution problem. These classifications—marginal, moderate, serious, severe, and extreme—translate to varying requirements with which Texas and nonattainment areas must comply.