Phoenix, Arizona — Hazardous air quality will intensify across the Phoenix metro area through Saturday evening, with rising ozone levels limiting outdoor activity and increasing health risks during peak afternoon hours.
According to the Arizona Department of Environmental Quality, ozone concentrations will build between 10 a.m. and 8 p.m. Friday and Saturday, with the most dangerous levels expected from 2 p.m. to 6 p.m. across Phoenix, Mesa, Scottsdale, Tempe and Glendale.
The pollution surge is driven by stagnant air, strong sunlight and existing emissions, allowing ozone to accumulate near the ground. This can trigger breathing difficulties, especially for children, older adults and those with asthma, while prolonged exposure may irritate lungs even in healthy individuals.
Along Interstate 10, Loop 101 and U.S. 60, drivers may notice light haze and reduced air clarity during peak heating hours, particularly in low-lying urban corridors where pollution concentrates. Outdoor workers and commuters face increased exposure during the afternoon commute.
This is part of a broader pattern of stable atmospheric conditions across central Arizona, limiting air dispersion and trapping pollutants near the surface.
Residents are urged to limit strenuous outdoor activity, avoid midday exercise, reduce vehicle use and delay gasoline-powered yard work until after sunset.
The highest health risk will occur between 2 p.m. and 6 p.m., when ozone concentrations peak and outdoor exposure should be minimized.
