PRESS RELEASE | ADEQ Issues PM-10 High Pollution Advisory for Maricopa County Effective March 25, 2021

ADEQ has issued a dust High Pollution Advisory (HPA) for March 25, 2021, for coarse particulate matter (PM10) in Maricopa County. This HPA is due to particle pollutant levels expected to accumulate enough to exceed the federal health standard for PM10.
People with heart or lung diseases, older adults and children are most likely to be affected by particle pollution. PM10 particles are so small they are able to travel into the respiratory tract where they can cause short-term health effects such as eye, nose, throat and lung irritation, coughing, sneezing, runny nose and shortness of breath. Exposure to these particles can also affect lung function and worsen medical conditions such as asthma and heart disease.
ADEQ recommends that the general public limit outdoor activity while the HPA is in effect, especially children and adults with respiratory problems.
During this HPA, ADEQ encourages residents and businesses to use these tips and resources to help make the air healthier to breathe:
  • Avoid or limit wood burning in residential fireplaces, chimineas, outdoor fire pits and similar outdoor fires (including at hotels and restaurants and individuals/businesses that have permits for open burning) 
  • Avoid using leaf blowers 
  • Avoid activities that generate dust, such as driving on dirt roads and using off-road vehicles 
  • Drive as little as possible, carpool, use public transit or telecommute 
ADEQ also urges businesses conducting dust-generating operations to be vigilant in their dust control measures.


High Pollution Advisory (HPA): Notifies the public that the level of an air pollutant is expected to exceed the federal health standard. 
High Pollution Watch: Notifies the public when there is potential for a pollutant to exceed the federal health standard.
Particulate Matter: State and county agencies measure levels of particulate matter (PM) in the air. PM is extremely small solid particles and liquid droplets that circulate in air. PM comes from combustion (cars, industry, wood burning) or dust stirred up into the air. High levels of PM occur when air is especially stagnant or windy. Two types of PM are measured: PM10, commonly called dust, and PM2.5, commonly called soot. PM10 refers to dust particles 10 microns or less and PM2.5 to soot particles 2.5 microns or less. For perspective, one strand of human hair is 70 – 100 microns in size. 


The Arizona Department of Environmental Quality (ADEQ) provides a daily forecast for air quality and issues HPAs or Health Watches when these conditions exist.

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ADEQ Public Information Officer | E-mail > | | 602-540-8072

The Maricopa County Air Quality Department (MCAQD) 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.
Clean Air Make More | View >

Valley Metro provides eco-friendly public transit options to residents of greater Phoenix and Maricopa County, including a clean-fuel bus fleet, low-emissions light rail, online carpool matching and bus trip mapping, and bicycle and telework assistance. Funding is provided by local, state and federal revenues; and administered by a board of 16 governments working to improve and regionalize the public transit system.
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