The Wyoming Department of Environmental Quality (DEQ) is continuing its ozone monitoring study in Upper Green River Basin through prime winter months when the pollutant is likely to form in and around oil and gas fields.

Dave Finley, administrator for the Air Quality Division (AQD), addressed a group of local residents and industry professionals on Jan. 21 at the Pinedale library, updating them on this year’s monitoring.

Now in it’s fourth year, the study is investigating how ozone is forming in the area — to determine “why on earth is this happening,” Finley said. Ozone is likely to form on hot summer days in urban areas; however, in recent years it has been a rising problem in Wyoming oil and gas fields during winter.

There are 16 monitoring sites set up around the Pinedale Anticline and Jonah gas fields where data will be collected through February and March, and be analyzed this summer, said Finley.

“There’s a ton of monitoring going on here, a ton,” he said.

Along with the constant monitoring, the AQD has an inventory from known emission sources. In the Jonah Field and Pinedale Anticline, inventories have been taken annually since 2004. Finley said the inventories help identify trends.

Since the ozone study began in 2007, things have changed, said Finley, like what sources of emissions are being monitored to how the emissions are being calculated. Basically, the study has moved from being vague and general to more precise, Finley said.

“Looking back on it, they were not as specific as they are today,” he said. However, monitoring continues to improve, Finley said, and they know exactly what weather conditions have to be in the area for ozone to form, like low winds, clear skies, snow coverage and a temperature inversion.

In the event of an ozone advisory, the DEQ office will alert industry, media and those on the department’s emailing and automatic phone call list. The public can also check the department’s Web site. Industry will also implement their winter ozone contingency plans to limit emissions. The advisory alerts will last 24 hours.

The Environmental Protection Agency (EPA) proposal for new standards on ozone levels was also discussed at the meeting last week. Earlier this month the EPA proposed to lower ozone levels to 60 to 70 parts per billion. The agency is expected to sign a final rule by Aug. 31.

For the complete article see the 01-29-2010 issue.

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