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Air Toxics

Air-toxics monitoring data can be used for finding pollution sources, evaluating air-permit applications, and identifying potential health concerns.

Types of Air Toxics monitoring networks

Community Air Toxics Monitoring Network

Canister samples collected throughout the state's urban and industrial areas are collected every 6th day and analyzed using a gas chromatograph-mass spectrometer.

Automated Gas Chromatograph Network

Automated Gas Chromatography samplers (AutoGCs) located throughout the greater Houston, Dallas, El Paso, Corpus Christi, and Odessa areas monitor for VOCs. One 40-minute sample is collected each hour and analyzed automatically on-site.


Carbonyl samples from the Houston, Dallas-Ft. Worth, and El Paso areas are collected every 6th day and analyzed for carbonyl compounds using high-performance liquid chromatography.

Polyaromatic Hydrocarbons

As part of an U.S. Environmental Protection Agency border grant, the TCEQ monitors polyaromatic hydrocarbon (PAH) concentrations in air at sites along the Texas-Mexico border. Samples are collected every 6th day and analyzed for PAH compounds using a gas chromatograph-mass spectrometer.


TSP, PM10 and PM2.5 filter samplers monitor for air toxics-metals. Twenty-four-hour samples are collected every sixth or third day.

Benzene Fenceline Monitoring

In December 2015, the U.S. Environmental Protection Agency issued the Refinery MACT (maximum achievable control technology) Rule to further control toxic air emissions from petroleum refineries and provide important information about refinery emissions to the public and neighboring communities. This rule requires refineries to monitor benzene emissions at key emission sources within their facilities and around their fence lines. The TCEQ toxicology staff have application/pdfevaluated this data to assess the potential for measured benzene concentrations to impact health.