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Maricopa County Homepage   MARICOPA COUNTY
Air Quality Department, Bob Huhn, PIO
1001 North Central Avenue
Phoenix, AZ  85004
Ph 602-506-6713

Ozone Season Begins April 1

PHOENIX (April 1, 2013) – Maricopa County’s official Ozone Season begins April 1 and will continue until the end of September.

Ozone pollution is more prevalent in the summertime because pollutants volatile organic compounds (VOCs) and nitrogen oxides (NOx) react more readily with heat and sunlight. Ground level ozone forms when emissions from vehicles, gas and diesel equipment, industrial and chemical processes, and even household activities react in the sun.

Last year was a busy one for air quality forecasters. There were 29 days when one or more monitors exceeded the federal ozone health standard in Maricopa County. During this time, the Arizona Department of Environmental Quality also issued eight high-pollution advisories and 33 health watches for ozone.

“Ozone is different than other pollution in that it is odorless and colorless, but it is just as dangerous to your health,” Maricopa County Air Quality Director Bill Wiley said. “Please pay attention to air quality alerts and do your part to reduce air pollution by driving less and refueling after dark.”

Ground level ozone pollution is a direct threat to your lungs and can trigger asthma, among other symptoms. Older adults and those with pulmonary conditions are more sensitive to elevated ozone concentrations. Children are at higher risk from elevated ozone levels because their lungs are still developing and they are most likely to be active outdoors.  They are also more likely than adults to have asthma.

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OZONE BACKGROUND:  Ground level ozone is formed by a chemical reaction that needs heat from sunlight, NOx and VOCs to form. The months of April through September make up the Valley’s longer-than-normal “ozone season.” 

Ozone pollution prevention tips:

• Drive less. When possible, carpool, van pool or use public transportation.

• Avoid waiting in long drive-thru lines, for example, at coffee shops, fast-food restaurants or banks. Park your car and go inside.

• Refuel your vehicle after dark or during cooler evening hours.

• Use low VOC or water-based paints, stains, finishes and paint strippers.

• Delay big painting projects until high-pollution advisories or health watches have passed.

• Conserve electricity.



About Maricopa County Air Quality Department


The Maricopa County Air Quality Department is a regulatory agency whose goal is to ensure federal clean air standards are achieved and maintained for the residents and visitors of Maricopa County. The department is governed by the Maricopa County Board of Supervisors and follows air quality standards set forth by the federal Clean Air Act.


The department offers air quality information and resources on its Clean Air Make More website.  Visit to learn more.


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