PINEDALE - A federal designation labeling Sublette County as a "dirty air" area for ozone pollution would require the state to institute increased safeguards for clean air, according to a panel of ozone experts.

That would most likely result in stricter regulations on emissions in the lucrative Jonah and Pinedale Anticline natural gas fields, speakers at an ozone forum said here Tuesday night.

Elevated levels of ozone, a noxious gas and respiratory irritant, prompted state officials to issue five air pollution advisories last winter in the Pinedale region. The Upper Green River Basin has registered at least slightly elevated levels of ozone in three of the past four winters.

The ozone warnings - the first ever issued in Sublette County by the Wyoming Department of Environmental Quality - drew the ire and concern of area residents, who attribute the increased ozone levels to oil and gas development in the two fields.

The U.S. Environmental Protection Agency may declare areas where air quality fails to meet federal ozone standards - currently limited to no more than 75 parts per billion during an eight-hour period - as "nonattainment" areas.

The designation would require Wyoming to develop cleanup plans, or "attainment" plans, said Peter Hess, a retired air pollution officer for San Francisco's Bay Area Air Quality Management District.

"The (attainment) plan would be your genesis … your roadmap to attain those air quality standards," Hess told a crowd of around 100 people during the forum.

"It's the most important element (to achieving reduced ozone levels) … and a lot of work needs to be put into this," he said. "You have to get ahead of the game (with the plan) to reduce emissions now."

Ground-level ozone is a potentially poisonous air pollutant that is created by chemical reactions between oxides of nitrogen and volatile organic compounds in the presence of sunlight.

Derek Montague with the University of Wyoming's Department of Atmospheric Science said emissions from industrial facilities and electrical utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of nitrogen oxides and volatile organic compounds.

He said the principal source of nitrogen oxides is the internal combustion engine, while the principal source of volatile organic compounds is fossil fuel use.

The tricky part

A citizen coalition in Sublette County petitioned the EPA in June asking for the nonattainment designation.

Hess said to achieve the designation, Gov. Dave Freudenthal must make a nonattainment recommendation to the EPA administrator by next March. The recommendation must be based on a complicated formula that incorporates a three-year average of ozone readings.

He said once it's submitted, the EPA would have one year to either concur, revise or return the recommendation back to the state. A final designation would be forthcoming by March 2010.

If the region receives a nonattainment designation, the state would then be required to draft an attainment plan that outlines what steps would be needed to meet desired ozone air quality standards.

"It typically takes three years or more to develop a plan that meets the muster of the EPA," Hess said. "And the plan must include an inventory of all emission sources contributing to the nonattainment, which in itself is a very difficult task."

Here's where the draft plan gets tricky, Montegue said.

He said the key to reducing ground-level ozone is to cut either nitrogen oxides emissions or volatile organic compound emissions, but not both at the same time.

Ozone concentration maps must be developed as part of the plan to help determine which pollutant emissions - NOX or VOC - should be reduced.

"It's extremely important to properly understand if NOX should be the limiting factor or if it should be a VOC-limited situation," Montegue said.

"If you make the wrong decision (on which pollutant to reduce), it could end up making the (ozone) situation worse."

Hess agreed.

"What are the tactics, or the right paths for the control of NOX or VOC, or what air quality mixture and mechanisms will you use? … That's what you have to determine," he said.

"It's very difficult to make that decision until the data is collected," he said. "It's not good to go forward until that information in known."

Industry officials have said they understand the concerns of area residents about elevated levels of ozone.

Energy officials said companies drilling in the Jonah and Anticline fields are aggressively working to address air quality issues, including using improved technology on drilling rigs to reduce the pollutants that help create ozone.

Officials said companies have been converting drilling rigs from diesel engine-powered to natural gas-powered, which can reduce NOX emissions by as much as 90 percent. They're also building liquids gathering systems to reduce truck traffic on gas field roads.

Southwest Wyoming bureau reporter Jeff Gearino can be reached at 307-875-5359 or at gearino@tribcsp.com.

* Last we knew: The Wyoming Department of Environmental Quality issued numerous ozone warnings last winter for Sublette County.

* The latest: More than 100 county residents attended an ozone public information forum in Pinedale Tuesday night to hear a panel of experts discuss ozone air quality and potential health effects of ozone.

* What's next: The state is conducting an ongoing $6 million air quality study in southwest Wyoming that is expected to be released next year.]]->