Air pollution from natural gas drilling in the Barnett Shale is a big problem but it can be easily controlled with existing technology, researchers said this week.

The giant natural gas field, with 7,700 wells and counting, produces nearly as much air pollution as all the cars and trucks in the Metroplex, according to a study by Al Armendariz of Southern Methodist University and Ramon Alvarez of the Environmental Defense Fund. And unlike most oil and gas production, it’s centered on a highly populated area.

"We have to come up with viable solutions," Alvarez said.

"The good news is that there are a lot of viable technologies to reduce the emissions."

Gas drilling creates several kinds of pollution.

Carbon dioxide and soot are created by the engines used to power pipeline compressors.

Methane, the primary ingredient in natural gas, is a powerful greenhouse gas. It can escape from leaky pipes and equipment, and it is also sometimes vented into the air when wells are being completed.

Volatile organic chemicals, including hazardous chemicals such as benzene and formaldehyde, are released from leaky tank batteries, where crude oil is separated from natural gas.

The year-round average for all types of drilling-related pollution is 191 tons per day. In the summer, when North Texas' air pollution is at its greatest, the emissions can rise to 307 tons per day because the heat causes more evaporation.

A draft of the study released in November pegged the number at 262 tons per day.

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