Section 12-2 - Air pollution emergency episodes (a) Conditions justifying the proclamation of an air pollution alert, air pollution warning or air pollution emergency shall be deemed to exist whenever the Division determines that the accumulation of air pollutants in any place is attaining or has attained levels which could, if such levels are sustained or exceeded, lead to a substantial threat to the health of persons. In making this determination, the Division will be guided by the following criteria: - (i) Air pollution forecast: An internal watch by the Division shall be activated by a National Weather Service advisory that an Atmospheric Stagnation Advisory, or the equivalent local forecast of a stagnant atmospheric condition is in effect.
- (ii) Air pollution alert: The alert level is that concentration of pollutants at which first stage actions begin. An alert will be declared when any one of the following levels is reached at any monitoring site:
- (A) PM10 - 350 µg/m3, 24-hour average;
- (B) SO2 - 800 µg/m3 (0.3 ppm), 24-hour average.
- (iii) Warning: The warning level indicates that air quality is continuing to degrade and that additional control actions are necessary. A warning will be declared when any one of the following levels is reached at any monitoring site:
- (A) PM10 - 420 µg/m3, 24-hour average;
- (B) SO2 - 1600 µg/m3 (0.6 ppm), 24-hour average.
- (iv) Emergency: The emergency level indicates that air quality is continuing to degrade to a level of significant harm to the health of persons and that the most stringent control actions are necessary. An emergency will be declared when any one of the following levels is reached at any monitoring site:
- (A) PM10 - 500 µg/m3, 24-hour average;
- (B) SO2 - 2100 µg/m3 (0.8 ppm), 24-hour average.
- (v) Termination: Once declared, any status reached by application of these criteria will remain in effect until the criteria for that level are no longer met. At such time, the next lower status will be assumed.
(b) Whenever the Division declares that one of the above mentioned levels exists, it shall take such control actions which in its best judgment will lower the pollutant concentrations.
020-12 Wyo. Code R. § 12-2