The Arizona Department of Environmental Quality has extended Thursday's ozone high pollution advisory (HPA) through Friday, Aug. 10.
The Valley saw some of the highest ozone readings of the season on Tuesday. Couple that with continuing high temperatures - 112 expected on Friday - and a return of wind flow from the east and ozone could be locked in the Valley through Saturday, the department said in a news release.
The forecast is calling for the return of an easterly wind flow over the next few days, said ADEQ Air Quality Division Director Eric Massey. Coupled with the excessive heat that is also in the forecast, high concentrations of ozone that may last for a few days are expected.
Ozone is created when other pollutants in the air are heated by the sun. Ozone can aggravate existing respiratory conditions, such as asthma.
The Maricopa County Air Quality Department will continue to enforce its mandatory no burn day restrictions during the HPA on Friday. This restriction includes individuals and businesses that have burn permits for open burning.
ADEQ recommends that children and adults with respiratory problems avoid outdoor activities on Friday and suggests the general public limit outdoor activity throughout the day.