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Research 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 research projects.
About Research 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.)

List of Toxicology Division Research Projects

By Fiscal Year

Aggregate production operations (APOs)
APOs are sites where materials have been removed from the earth and include TCEQ regulated activities such as rock crushing. APOs may be located close to communities, and this has led to community concerns about potential air quality impacts of APO activities. Because silica is present in soil, sand, and rock formations, silica emissions can be associated with APO activities. The TCEQ conducted an air monitoring project using published monitoring methods to measure crystalline silica concentrations near APOs. The goal was to determine what contribution, if any, the APO facilities have to ambient air concentrations of crystalline silica and total particulate matter (PM2.5) relative to background levels in the Central Texas area.

Overall, this monitoring study found that total PM2.5 concentrations were not measurably impacted by downwind APO operations. For crystalline silica, only the monitor downwind of a sand mine showed higher levels compared to the background site, but concentrations were still below levels of health concern.

The final report of the monitoring study is available here: