PINEDALE (WNE) — The Upper Green River Basin’s ozone levels continued to peak from April above the federal standard of 70 parts per billion, with the highest reported 1-hour level of 86 ppb on April 11 at the Pinedale Gaseous air-quality monitoring station. 

Last week, the Wyoming Department of Environmental Quality’s Air Quality Division (AQD) announced a forecast of “ozone outlooks” from Sunday, April 9, through Wednesday, April 12. 

AQD staff also forecast possible ozone exceedances and called for a voluntary Ozone Action Day on April 11 and soon added April 12. 

The AQD measures and records 1-hour and 8-hour ozone levels around the Upper Green River Basin at its Pinedale, Big Piney, Boulder, Daniel South and Juel Spring air quality monitoring stations with current and historical data for each live site. 

On Thursday, April 13, AQD released a new set of “ozone outlooks” forecast for Saturday, April 15, through Monday, April 17. 

Operators, businesses and the public are asked to delay burn piles, construction activities, deliveries, production, idling and any other engine uses that create emissions. 

“Unseasonal” winter ozone developed in the Upper Green River Basin with expanded drilling and production oil-gas development in the Pinedale Anticline, where air monitoring is required, and Jonah Field. 

It is caused when high human-produced emissions of nitrogen oxides and volatile organic compounds (VOC) are overheated by sunlight and snowbank reflections to form the tasteless, invisible gas.

Excess ozone exacerbates existing respiratory conditions and can cause bronchial illnesses in residents of all ages.