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Toxicological Evaluations of Ambient Air Monitoring Data

Evaluations of air quality data collected across the state for potential health effects and odors.

The TCEQ evaluates measurements of air toxics in ambient air collected from air monitoring sites that are located throughout the state. Toxicology personnel evaluate these measured chemical concentrations for their potential to cause health effects and odors. These evaluations are designed to help the agency focus its resources. Although the evaluations may present theoretical estimates of risks to health, they are not designed as comprehensive assessments of individual health risks.

Evaluations of air monitoring data collected in TCEQ regions with ambient monitors are available as Portable Document Format (PDF) documents. Help with PDF).

Latest Toxicological Evaluations 2020

Region 1 Amarillo
Region 3 Abilene
Region 4 Dallas/Ft Worth
Region 5 Tyler
Region 6 El Paso
Region 7 Midland
Region 10 Beaumont
Region 11 Austin
Region 12 Houston
Region 13 San Antonio
Region 14 Corpus Christi
Region 15 Harlingen
Region 16 Laredo

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Previous Toxicological Evaluations

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Types of Data Evaluated

Types of data available from the various monitoring networks may include:

  • 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 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.
  • 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.
What Do We Compare Monitored Data To?

For evaluation of ambient air monitoring results, acute and chronic inhalation reference values and inhalation unit risk factors are used to assess the potential for exposure to the measured concentrations to impair human health.

To assess potential welfare effects for monitoring results, the TCEQ toxicology staff uses odor- and vegetation-based ESLs.

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