The Arizona Department of Environmental Quality has issued an Ozone High Pollution Advisory (HPA) for Friday

The Arizona Department of Environmental Quality has issued an Ozone High Pollution Advisory (HPA) for Friday, May 2, 2025, and a PM10 HPA for Sunday, May 4, 2025. 
 

Take Action

• Drive less, carpool, use public transit, or telecommute. For information on transportation alternatives, visit ShareTheRide.com.
• Fuel your vehicle after dark or during cooler evening hours.
• Reduce wait time in long drive-thru lines. Park your vehicle and walk inside at coffee shops, fast-food restaurants, curbside pick-up, and banks.
• Use low-VOCs (volatile organic compounds) or water-based paints, stains, finishes, and paint strippers.
• Delay large painting projects until HPAs have passed.
• Properly seal containers of household cleaners, garage and yard chemicals, and other solvents to prevent vapors from evaporating into the air. Eliminate wood burning in fireplaces, stoves, chimeneas, and outdoor fire pits.
• Avoid using leaf blowers. Use a rake or broom to keep debris out of the road and away from storm drains, ditches, and streams.
• Conserve electricity.

HPA 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.
• Off-highway vehicles are prohibited from being used.

Transportation Coordinators

Due to unhealthy levels of particulate matter, all Transportation Coordinators are requested to email employees and activate your HPA plans. The department encourages the use of alternative modes of transportation, especially when pollution levels are expected to be on the rise.

Businesses conducting dust-generating operations must be vigilant of their dust control measures. Workers may need to cease operating, after stabilizing disturbed areas, if water application and other dust control measures prove ineffective.

Ozone: Ground level ozone is formed by a chemical reaction that needs heat from sunlight, nitrogen oxides and VOCs to form. The months of April through September make up our Valley’s longer-than-normal "ozone season."

PM10 is coarse particulate matter less than 10 micrometers in diameter that are generally emitted from sources such as vehicles traveling on unpaved roads, materials handling, and crushing and grinding operations, as well as windblown.

"High Pollution Advisory" or "HPA" means the highest concentration of pollution may exceed the federal health standard. Active children, adults, and people with lung disease such as asthma should reduce prolonged or heavy outdoor exertion.