Rising ozone levels and expected dust from high winds on Saturday are sparking an air quality health watch from the Arizona Department of Environmental Quality.
The Valley has been under several high pollution advisories and health watches because of high ozone levels this week. A health watch is issued when particulate or ozone levels approach federal standards.
Ozone is a pollutant that can trigger respiratory issues. It is created when other pollutants in the air are heated by the sun.
People with respiratory illness, as well as the young and elderly, may want to reduce outdoor exposure on Saturday.