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Special Projects

The TCEQ Toxicology Division (TD) has been involved with studies investigating human exposure to airborne toxic chemicals and the potential of these exposures to cause adverse health effects. This page contains a list of projects.

About Special Projects

These studies have been critically important as they have not only led to a greater understanding of air pollution and more knowledgeable decision-making by the TCEQ, but they have also become an invaluable way to address community concerns, since many of these studies were originally requested by citizens.

Studies have been completed in Houston, Midlothian, and the Dallas–Fort Worth area as well as the Corpus Christi and Barnett Shale areas. (The Barnett Shale is a large natural gas reserve encompassing more than 5,000 square miles and covering at least 17 counties in North Texas.)

Air Pollutant Concentrations Near Texas Roadways

This year-long study was conducted in 2007.

Other states have shown elevated concentrations of air pollutants near roadways, with concentrations rapidly falling to background levels with increasing distance from the roadways. The Air Pollution Concentrations Near Texas Roadways study sought to evaluate whether or not this holds true for Texas roadways. In addition, the study sought to determine how pollutant concentrations associated with roadways correspond to the type of roadway present (e.g., highway vs. local streets). Several different types of compounds were measured (ultrafine particles, carbon monoxide, oxides of nitrogen, volatile organic compounds, particle-bound organics like polycyclic aromatic hydrocarbons, and carbonyls) at three different types of roadways (arterial highway, limited access highway, and a surface highway). The overall observation for this study was that for virtually every roadway type, and independent of whether air flow was parallel to or perpendicular to the roadway, concentrations generally decayed exponentially and returned to background levels within a few hundred meters of the roadway.

Hillcrest Community Environmental Investigation (HCEI)

This two-phase environmental investigation was conducted in 2010 and 2011.

In 2008, Texas A&M University Health Science Center scientists and the Citizens for Environmental Justice (CFEJ) conducted a pilot study that detected benzene in the blood of some Hillcrest community residents. In response to the results of this study, and at the request of the Hillcrest community, the TCEQ developed a community environmental investigation that incorporated input from the Hillcrest Community. The main objective of the Hillcrest Community Environmental Investigation was to determine whether there are environmental impacts from volatile organic compounds to soil, groundwater, or ambient air in the Hillcrest community and adjacent areas. A health effects evaluation of the study data concluded that exposure to the reported levels of volatile organic compounds in the subsurface soil and groundwater samples would not be expected to cause adverse health effects.

Houston Air Toxics Biomarkers of Exposure Study (HATBES)

This year-long study was conducted in 2008 and 2009.

The original intent was to integrate this study with two other on-going Houston studies at the time: the Houston Exposure to Air Toxics Study and a University of Texas Medical Branch biomarker of inflammation study. However, due to unforeseen circumstances, including difficulties with recruiting and retaining volunteers after Hurricane Ike, this study recruited from the general population within the Manchester and Aldine areas. The Houston Air Toxics Biomarkers of Exposure Study investigated the utility of measuring various biomarkers of exposure to volatile organic compounds in human populations. HATBES also sought to determine the relationship between concentrations of organic contaminants in air and biomarkers of exposure in serum and urine. Study conclusions found there were no significant differences detected between ambient air exposures or biomarkers of exposure between the two residential communities.

Houston Exposure to Air Toxics Study (HEATS)

This multi-year collaborative study was completed in 2009.

HEATS is one of the largest studies on air toxics ever undertaken in Houston, and was designed to help us better understand how toxics that people breathe compare to toxics measured at stationary air monitors. The HEATS project was a multi-year collaborative study involving local universities; state, federal, and local government agencies; and research organizations. HEATS assessed the relationship between personal exposures and ambient concentrations of select hazardous air pollutants by monitoring residential indoor, outdoor, and personal air concentrations. HEATS also examined population-level health and risk perception through the administration of questionnaires. The main study conclusion was that personal exposures in the two study areas are similar and do not appear to reflect the differences in the type and density of point source emissions or the ambient concentrations as measured at fixed sites in each of the areas.

Midlothian, TX Ambient Air Collection & Analytical Chemical Analysis

This year-long study was conducted in 2008 and 2009.

In December, 2007, the Texas Department of State Health Services (DSHS) released a draft health consultation for Midlothian, Texas: Midlothian Area Air Quality Part 1: Volatile Organic Compounds (VOCs) and Metals. In the draft consultation, DSHS classified Midlothian as an indeterminate public-health hazard because they felt further information was needed to fully characterize the extent of any public health hazard posed by air contaminants in Midlothian. In response, TCEQ met with a citizen advisory group to understand the questions and concerns with regard to air quality in their city. The TCEQ also developed a study in conjunction with the citizen advisory group that would help answer those questions and concerns, as well as fill data gaps noted in the DSHS draft consultation. The TCEQ contracted with URS Corporation for the collection and analytical chemical analysis of ambient air samples in Midlothian. The overall conclusion of the study was that while nearby industry does have a measureable impact on the detected levels of some compounds in the air, all measured levels of volatile organic compounds and speciated metals were well below their respective screening levels and are not of a health concern.

Contact us for more information on these projects.