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CASPER, Wyo. (AP) — For the first time in about six years, state regulators this week have invoked special conditions that require energy companies to reduce pollution from oil and gas fields in southwest Wyoming.
The Wyoming Department of Environmental Quality issued so-called ozone action days in the Upper Green River Basin for Friday and Saturday. Ground-level ozone is the primary ingredient for smog. Wyoming issues action days when the weather forecast is favorable to producing ozone.
Ozone levels hit 81 parts per billion in the town of Boulder on Thursday. The federal standard for ozone is no greater than 70 ppb over an eight-hour period.
On action days, oil and gas producers take steps such as reducing truck idling, limiting refueling and reducing vehicle speeds.
Winter ground ozone needs a layer of snow, no wind and temperature inversion to ramp up. Air contaminants from oil and gas activities, car exhaust and other sources react with sunlight to create ozone, with highest levels usually occurring between noon and early evening, according to the Environmental Protection Agency.
The state partnered with environmental groups and local companies to develop rules to address high emissions that can occur in the Wyoming oil and gas fields.
The years since the last ozone spike is a credit to what's been done in the Upper Green so far, said Jon Goldstein, a senior policy adviser at the Environmental Defense Fund and a partner in reducing Upper Green River air pollution for years.
However, it's also the result of other factors, weather and reduced production during the low prices of natural gas, he told the Casper Star-Tribune (http://bit.ly/2kcBgTD).
"I think that the people who are paying attention to the problem don't feel like it's been solved," said Chris Merrill, associate director of the Wyoming Outdoor Council. "We know we've been lucky in previous winters where we didn't get the full snow-covered ground and all of those conditions that come together to create wintertime ozone formation."
The action day is a reminder that ozone levels can still be a threat in Wyoming, and more work needs to be done, Merrill said.
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Information from: Casper (Wyo.) Star-Tribune, http://www.trib.com
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