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Denton air ranks as state’s dirtiest

Profile image for By Peggy Heinkel-Wolfe
By Peggy Heinkel-Wolfe

City’s average ozone level for past 3 years is highest in Texas

Update: 11:12 a.m. Wednesday

Joseph Hubbard, spokesman for the Environmental Protection Agency, confirmed that the agency is still reviewing the state's plan to clean up the region's air. TCEQ has until May 1 to certify and submit 2016 ozone data to the EPA.

"No action is expected before the end of the year," Hubbard wrote in an email.


The state’s ozone season ended in October with Denton still holding the biggest bag.

The city’s average ozone level stands at 80 parts per billion, the highest in Texas, according to state records.

State environmental officials say they have a plan to see that average drop to 75 ppb by the end of next year. The region has seen ozone levels drop in big ways in the past few years, but those big decreases have been followed by years with increases. Scientists at the Texas Commission on Environmental Quality say the weather is a factor.

Ozone is formed when emissions from power plants, factories and vehicles combine in sunlight. The region’s hot, dry summers can make for more ozone in some years. At ground level, ozone burns lung tissue the way sun burns the skin.

This year, a cooler-than-normal May and a wet and windy August helped keep the “bad air” days to a minimum. Last year, that wasn’t the case. Enough “bad air” days in 2015 made the three-year average from Denton Enterprise Airport highest in the state, higher even than three years (2014-16) of ozone levels recorded across greater Houston.

Scientists generally agree that ozone levels below 60 to 65 ppb are “safe enough” to breathe. However, some critics say that standard is too costly for the benefit it brings.

Doctors believe the region’s poor air quality is contributing to high asthma rates and other ailments. Childhood asthma rates in North Texas run about three times higher than the rate statewide, and twice the nationwide rate. The Dallas County Medical Society estimated last year that a small reduction in North Texas ozone levels could have prevented 165 hospital admissions, 350 emergency room visits, 120,000 school absences, 77 deaths from lung and heart disease and 150,000 restricted activity days, saving the region’s economy about $500 million.

But TCEQ and other Texas officials believe that putting stricter emissions requirements on power plants, factories or the oil and gas industry would cost the Texas economy too much for the health savings it brings. For example, coal-fired power plants need expensive improvements to lower emissions, which raises the cost of electricity.

For the past 20 years, ozone levels have dropped in North Texas and around the country, thanks in large part to cleaner-burning cars.

The Clean Air Act requires TCEQ to consider the weather in its plan to clean North Texas air. Because people continue to buy new cars and cleaner car fuels are coming soon, TCEQ didn’t add any big, new strategies to its cleanup plan for 2017. The agency says the region’s air should drop to 75 ppb without putting new requirements on coal plants, cement plants or oil and gas producers.

TCEQ spokeswoman Andrea Morrow said its still possible the state’s plan will work, calling a reduction of ozone to 75 ppb “certainly feasible in the near future.”

The ability of the TCEQ’s model to make accurate predictions about its plan has come under increasing scrutiny from environmental advocates, researchers and the Environmental Protection Agency, which oversees compliance with the federal Clean Air Act.

EPA officials have been reviewing the state’s plan for compliance for several months. But they declined to comment on the progress of that review for this story.

In April, U.S. Rep. Eddie Bernice Johnson, D-Dallas, and U.S. Rep. Marc Veasey, D-Fort Worth, wrote a letter to the EPA, asking them to reject the state’s plan and provide a federal plan to clean up North Texas air instead.

PEGGY HEINKEL-WOLFE can be reached at 940-566-6881 and via Twitter at @phwolfeDRC.



Here are some key readings (in parts per billion) for the 2016 ozone season, which ended in October:

98 ppb Highest one-hour ozone level (Denton, June 8)

13 “Bad air” days (eastern counties in Dallas-Fort Worth area, including Denton)

83 ppb Average ozone level

11 “Bad air” days (western counties in D-FW area)

95 ppb Average ozone level

SOURCE: Texas Commission on Environmental Quality