Cheyenne, Wyo. – Another ozone advisory has been issued for Wyoming's Upper Green River Basin.
The advisory goes into effect Saturday and is expected to last several days due to weather conditions.
State regulators this week issued the first ozone advisories for the basin in more than two years. Ozone coincides with smog and can cause respiratory problems, especially for children, the elderly and people who already have respiratory problems.
Those who are sensitive to ozone are warned to limit strenuous or prolonged outdoor activities, especially in the afternoon and evening.
The basin has seen heavy gas development in recent years. The smog results from when conditions are right during the winter. Such conditions include snow on the ground, sunshine, a temperature inversion and air pollution including nitrogen oxides and volatile organic compounds.