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Ozone Season and Clean Air Action Days

Ozone season begins March 1 and runs through the end of September.  Air Quality Division meteorologists keep their eyes on the skies year-round and continued to evaluate air quality forecasts. These evaluations may cause them to call for Clean Air Action Days when necessary. These are days when weather conditions may cause air to be unhealthy for some individuals. On these days, people are encouraged to change their activities in order to minimize their exposure.


Graphic showing ozone formation process

Clean Air Action days are called when levels of ozone or particulate matter put people at risk. During ozone season, the likelihood of a Clean Air Action Day being called. High ozone near the ground can have harmful effects for sensitive individuals. People may sign up to receive air quality alerts at to be better prepared on those days when ozone is high.

Two Air Quality Division meteorologists talk about Clean Air Action days and why they are important in a short educational video meant to encourage people to sign-up to get air quality alerts and to take action when weather conditions may increase impacts on sensitive people.