The Arizona Department of Environmental Quality has issued a health watch for ozone air pollution for Friday, Aug. 16.

A health watch means the highest concentration of ozone pollution is expected to approach the limit that meets federal health standards.

Active children and adults, and persons with lung disease such as asthma, should reduce prolonged or heavy exertion outdoors.

Ground level ozone is formed by a chemical reaction that needs heat from sunlight, nitrogen oxides and volatile organic compounds [VOCs] to form. The months of April through September make up the Valley’s longer-than-normal “ozone season.”

More information is available at cleanairmakemore.com or azdeq.gov.