Results from a comprehensive air pollution study confirm what experts have long suspected: Emissions from petrochemical complexes in Houston are responsible for the extraordinarily high levels of ozone that occur there.

	"We see an unmistakable signal that hydrocarbons from the petrochemical industry are causing Houston to look really different from other urban areas." Lawrence I. Kleinman, Brookhaven National Laboratory

"I think it's about as clear-cut a case as you would ever find," says Lawrence I. Kleinman, an atmospheric chemist at Brookhaven National Laboratory.

Kleinman and other Brookhaven scientists are among hundreds of researchers from more than 40 public and private institutions who took part in the Texas 2000 Air Quality Study (C&EN, Nov. 6, 2000, page 32). Using specially equipped planes, the scientists collected air samples in Houston, Nashville, New York City, Philadelphia, and Phoenix. They measured concentrations of nitrogen oxides (NO_x) and volatile organic compounds (VOCs), two ozone precursors, as well as ozone itself and other species. From those data, they calculated the rate of ozone production [Geophys. Res. Lett., 29, 10.1029/ 2001GL014569 (2002)].

Most of Houston resembles the other cities, Kleinman and coworkers report, with similar levels of NO_x, VOCs, and ozone production rates. But in the Houston Ship Channel region, where scores of industrial facilities including oil refineries and chemical plants are located, they found high concentrations of VOCs not seen in the other cities or in other parts of Houston. Specifically, the researchers found ethylene, propene, and butenes. As a result, the ozone production rate can be as much as five times higher near the ship channel.

The Texas Natural Resource Conservation Commission plans to use these and other forthcoming results from the study to formulate strategies to improve air quality.

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