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The original item was published from 7/31/2023 9:10:55 AM to 8/1/2023 10:19:40 AM.

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Air Quality ONLY

Posted on: July 31, 2023

[ARCHIVED] Ozone High Pollution Advisory issued for Monday, July 31 and Tuesday, August 1

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The Arizona Department of Environmental Quality (ADEQ) is issuing an Ozone High Pollution Advisory (HPA) for Maricopa County issued for Monday, July 31 and Tuesday, August 1. This HPA is due to ozone levels expected to accumulate enough to exceed the federal health standard for ozone.

Ground-level ozone forms when emissions from vehicles, gasoline and diesel equipment, industrial and chemical processes, and other everyday activities react to sunlight. Because these emissions react more readily to sunlight, ozone pollution is more prevalent during the spring and summer months.

Although some people are more sensitive than others, all county residents can be affected by ground-level ozone pollution, which is harmful to lungs and can trigger asthma. Children are at the greatest risk from ozone because their lungs are still developing, they are most likely to be active outdoors, and they are more likely than adults to have asthma. Adults with asthma or other lung diseases and older adults are also sensitive to ozone. Public should limit outdoor activity while the HPA is in effect, especially children and adults with respiratory problems.

ADEQ and Maricopa County Air Quality Department (MCAQD) recommend residents and businesses use the following tips and resources to reduce ozone pollution and make the air healthier to breathe:

  • Promote remote. Telework to reduce traffic.  
  • Drive less. When possible, carpool, van pool, or use public transportation.
  • Avoid waiting in long drive-thru lines. Park your car and go inside.
  • Ride your bike or walk to work.
  • Sweep instead of using your leaf blower.
  • Refuel your vehicle after dark or during cooler evening hours.
  • Use low-volatile organic compounds (VOC) or water-based paints, stains, finishes, and paint strippers.
  • Delay painting projects until high pollution advisories or health watches have passed.
  • Make sure containers of household cleaners, garage and yard chemicals, and other solvents are sealed properly to prevent vapors from evaporating into the air
  • Visit to learn more about reducing air pollution

This High Pollution Advisory includes the following restrictions:

  • Wood burning in residential fireplaces, chimeneas, outdoor fire pits, and similar outdoor fires is prohibited in Maricopa County. This includes individuals and businesses which have burn permits for open burning.
  • Employees and contractors of government entities are prohibited from operating leaf blowers. Residents are encouraged to avoid leaf blowing during HPAs.
  • Off-road vehicle use should be avoided.  



 High Pollution Advisory (HPA): Notifies the public that the level of an air pollutant is expected to exceed the federal health standard.

 Ozone: Ground-level ozone is formed by a chemical reaction among sunlight, nitrogen oxides (NOx) and VOCs.


MEDIA CONTACT [English/Spanish]

Ari Halpert

602-501-1266 cell

602-506-6713 desk

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About Maricopa County Air Quality Department 

MCAQD’s mission is to improve the air of Maricopa County so customers, residents, and visitors can live, work, and play in a healthy environment. MCAQD is governed by the Maricopa County Board of Supervisors and follows air quality standards set forth by the federal Clean Air Act. For air quality information and resources, visit

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Download MCAQD’s Clean Air  app! It is free to download and use and is available on the App Store for iPhone and iPad and on Google Play for Android.

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