Halfway through the ozone season in southwestern Wyoming, two consecutive days with the right ingredients to create ground level ozone in the Upper Green River Basin have sparked controls on the oil and gas industry.
The Wyoming Department of Environmental Quality declared Monday and Tuesday ozone action days, meaning operators in the basin will limit activities that contribute to emissions, such as idling trucks.
Ozone is the principle ingredient for smog. It’s created when sunlight and weather conditions interact with contaminants like car exhaust and industrial emissions from oil and gas production.
The Upper Green River Basin has been prone to ground level ozone since the area became a prolific producer of natural gas. Widespread development, winter snow cover, lack of wind and the bowl shaped geography of the Upper Green led to hazardous air quality conditions with smog comparable to that of more industrial and populate cities like Los Angeles.
In the years since, Wyoming instituted a series of controls that applied solely to the Upper Green, including the use of infrared equipment to find infrastructure gas leaks. Another aspect of the state’s regulatory approach to air quality in the Upper Green are ozone action days, when oil and gas companies change their day-to-day operations to try and limit emissions.
Monday and Tuesday are the first ozone action in this years’ ozone season, which lasts from January to March.
Last year, the region made it through the season with no ozone days. The previous year, 2017, had a dramatic spike in the conditions that precipitate ground level ozone forming, leading the Department of Environmental Quality to call for a number of action days.