Why Denton's Air Quality Is the Worst in Texas

Here's another reason why Texas should secede: We'll avoid getting in trouble for repeatedly violating the Clean Air Act. New data shows that North Texas is continuing its 16-year-streak of failing to be in compliance with the federal law.

The Clean Air Act stipulates that ozone pollution doesn't exceed 75 parts-per-billion. But this year's measurements from the Texas Commission on Environmental Quality show that much of North Texas has been hovering above even 80 parts-per-billion, which means we're also breaking looser Clean Air Act restrictions from 1997.

The grunge-era pollution is looking especially bad in Denton County, where the three-year, eight-hour average of ozone readings was 87 parts-per-billion, tying with Houston as the highest average in the state. How did Denton County achieve this feat?

"It's a mystery that everyone wants to know the answer to, and a lot of us have different theories about it," says Jim Schermbeck, director of the environmental watchdog Downwinders at Risk.

All of that ozone pollution has actually been many years in the making (and the subject of a three-part Denton-Record Chronicle series from 2009). Here are some of the popular theories:

Cement Kilns South of Dallas, in Midlothian, sits the country's largest concentration of cement plants, a major polluter in North Texas. And areas downwind, like Denton, tend to bear the brunt of the pollution. (More on that below.)

In 2009, the cement industry agreed to a plan calling for stricter pollution controls, according to Denton Mayor Mark Burroughs, but it was the not so environmentally friendly Texas Commission on Environmental Quality that rejected it. Around that same time, the Obama administration had also begun drafting new regulations to limit pollution from the whole cement industry. But as we reported last year, the EPA and Obama flaked on the proposed rules at the last minute.

There have been some improvements, notably in June, when one of the big cement firms in Midlothian agreed to close two of its notorious kilns and replace a third with a cleaner model.

Idling Trucks When your date pulls up to your parent's house in his Mustang and honks at you for five minutes while leaving the ignition running, he might seem kind of dangerous and cool. When a guy driving a 14,000-pound truck does this, he's just an asshole.

Lots of truck traffic bustling through Denton means lots of emissions, 78 percent of which comes from the trucks just idling, according to a recent study by the Council of Governments. As the Denton Record-Chronicle recently reported, Collin, Dallas, Kaufman and Tarrant counties have all implemented anti-idling measures, barring trucks of 14,000 pounds or more from idling for more than five minutes. But Denton County has yet to adopt such a policy.

The Natural Gas Industry This is the one environmental groups like Schermbeck's Downwinders at Risk focus on. There are more than 14,000 gas wells and 15,000 oil wells in the Barnett Shale, according to TCEQ data from January 2012. It's not just fracking itself but the accompanying compressor stations, processing plants and trucks that make the whole industry possible. And while other industries -- even cement -- are required to make an effort to offset their pollution under the Clean Air Act, the natural gas industry has been largely exempt, making it harder for the rest of the state to be in compliance.

About a year ago, Eduardo P. Olaguer, the Director of Air Quality Research at the Houston Advanced Research Center, looked at the Barnett Shale and reported in a study that meeting federal ozone standards will be nearly impossible, "unless significant controls are placed on emissions from increased oil and gas exploration and production."

Wind Southeast to northwest winds mean that Denton often gets stuck with the pollution created by the Midlothian region and other parts of Texas. Downwinders at Risk (notice their name) writes that the whole metroplex is effectively "getting squeezed between gas pollution being produced in the middle of its urban areas, and gas pollution blowing in from the south."

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Amy Martyn
Contact: Amy Martyn