The Arizona Department of Environmental Quality has issued a high pollution advisory for Maricopa County this weekend.
ADEQ officials say ozone is expected to jump above the exceedance threshold.
They say hourly ozone values will ramp up by early afternoon and reach maximum values by mid-afternoon through early evening on both Saturday and Sunday.
ADEQ recommends that residents in Arizona's most populous county limit outdoor activity while the high pollution advisory is in effect, especially children and adults with respiratory problems.
