UGRB Ozone Outlook for April 9-11, 2023

Wyoming Department of Environmental Quality  | view as a webpage

Wyoming Department of Environmental Quality

UGRB Ozone Outlook for April 9-11, 2023

This is notification that the Air Quality Division (AQD) of Wyoming’s Department of Environmental Quality (DEQ) has issued an Upper Green River Basin (UGRB) Ozone Outlook starting on Sunday, April 9 and forecasted to persist through Tuesday, April 11, 2023. The AQD will continue forecasting daily to determine if an Ozone Action Day should be issued to implement Ozone Contingency Plans.

UGRB Ozone Outlooks are issued when meteorological conditions conducive to ozone formation are forecasted to persist for multiple days in the UGRB Ozone Nonattainment Area. Wintertime ozone forms in the Basin when there is a presence of ozone precursor emissions including oxides of nitrogen and volatile organic compounds coupled with meteorological conditions, such as strong temperature inversions, low winds, snow cover, and sunlight.

During an UGRB Ozone Outlook, please consider reducing ozone precursor emissions. Some actions that could be done to reduce ozone precursor emissions include: minimizing idling of vehicles and engines, not overfilling gas tanks, tightening fuel caps, deferring truck and equipment fueling to evening hours, and postponing construction activities and open burning. When UGRB Ozone Outlooks are issued, please consider postponing non-essential activities or completing essential activities prior to the days included in the UGRB Ozone Outlook to reduce precursor emissions and ground-level ozone formation.

Current information on ozone levels at the Air Quality Division's monitoring stations at Pinedale, Daniel South, Boulder, Big Piney, and Juel Spring can be found at More information on ozone and the health effects of ozone are available at the Wyoming Department of Health website,