After a one-day break from an ozone health watch, the Arizona Department of Environmental Quality has issued a health watch for ground-level ozone for Tuesday.
The Valley was under a health watch Thursday, Friday, Saturday and Sunday as ozone levels crept up with rising temperatures.
Ozone is an invisible gas that is created when other pollutants in the air are heated by the sun. Vehicle use helps add to the possibility of ozone production in the Valley, but Arizona also receives some ozone that moves in from California.
A "health watch" means the highest concentration of pollution may approach the federal health standard. Unusually sensitive people should consider reducing prolonged or heavy outdoor exertion during a health watch.
ADEQ also recommends that you:
• Avoid waiting in long drive-thru lines. Park your car and go inside.
• Unplug unused appliances.
• Fuel your vehicle after dark or during cooler evening hours.
• Connect your outdoor lights to a timer or use solar lighting.
To find a carpool or vanpool, visit www.ValleyMetro.org or call (602) 253-5000.