Texas' Research-Based Regulations Reduce Ozone Statewide

Texas has devoted more funds to air quality research during the past decade than any other state in the country. The state has sponsored two major field studies, the Texas Air Quality Study (TexAQS) 2000 and Texas Air Quality Study II (TexAQS II). Between state resources and in-kind support from national organizations, colleges, and universities, nearly $50 million has been invested in investigating the complex and often unique issues associated with ozone formation in Texas. This science has lead to targeted regulations and air quality improvements.

TexAQS 2000

TexAQS 2000 resulted in the TCEQ taking major steps to improve the reporting of emissions inventories from industrial sources along the Texas Gulf coast. The better inventories have improved the computer-based predictive tools used to design air quality plans. The improved understanding of what contributes to high ozone in Houston helped the agency develop regulations to reduce smog-forming pollutants that has yielded measurable results at air quality monitors. In the 1990s, one-hour ozone readings in the Houston area were as high as 130 parts per billion and eight-hour ozone readings were always more than 100 ppb. The trend in this decade continues to move in a direction where eight-hour ozone readings are as low as they have ever been and are close to compliance with the 1997 standard of 80 ppb.

Another successful outcome of the study was a better understanding of the unique meteorological features that affect ozone, particularly in the Houston area. In understanding air circulation and the land-sea breeze, air quality planners can take into account the part of nature that cannot be addressed by pollution-control strategies. However, when the meteorological influences are factored out, the ozone trend is still clearly downward—thus, the implemented control strategies are working to reduce emissions and, consequently, ozone.

The field study gave the agency answers regarding the impact of power plants, cement kilns, and other industrial sources located outside the urban core on ozone formation in the urban areas. Aircraft flights conducted during TexAQS 2000, and—over the course of several years—through a special contract project with Baylor University, tracked plumes from the sources to the urban areas. Results from the analyzed data gathered have led to appropriate regulatory changes. 

TexAQS II

The TexAQS II Field Study built on the success of TexAQS 2000, covering a larger area of Texas. Its findings have helped revise the SIP, which is improving air quality throughout the state and helping Texas meet the federal Clean Air Act requirements.