Air Pollution Advisory: Ozone
For Upper Green River Basin/Sublette County
by Wyoming Department of Environmental Quality (DEQ)
February 27, 2008
The Air Quality Division of Wyoming’s Department of Environmental Quality is issuing an air pollution advisory beginning Wednesday, February 27, for the Upper Green River Basin, in Sublette County.
The advisory is for ozone, which is an air pollutant that can cause respiratory health impacts especially to children, the elderly and people with existing respiratory conditions.
People in these sensitive groups should limit strenuous or extended outdoor activities, especially in the afternoon. The advisory is expected to be in effect for several days. The DEQ will issue another advisory when conditions change and ozone levels return to normal.
The Air Quality Division advises that people in sensitive groups should avoid strenuous outdoor activity when eight-hour ozone values are between 85 and 105 parts per billion. The general public should avoid such activity when eight-hour ozone values are above 105 parts per billion.
Elevated wintertime ozone is an unexpected occurrence which is being studied by the Division. Typically, higher ozone levels occur in large cities in the summer when there is plenty of sunlight to cause the photochemical reactions in the atmosphere which lead to ozone formation.
In the past week, the highest eight-hour ozone levels at the Division’s monitor at Daniel was 76 ppb, the highest at the Jonah monitor was 85 ppb, and 122 ppb was reached at the Boulder monitor.
All of these levels are preliminary and may change after the data has been subjected to the Division’s quality control checks.
Ozone appears to be elevated in the Basin when there are strong temperature inversions, low winds, snow cover, and bright sunlight, and levels return to normal when any one of those conditions change. Current information on ozone levels at these three monitors can be found at www.wyvisnet.com.
For further information, contact Keith Guille, Wyoming DEQ Public Information Officer, at 307-777-7781.