The Arizona Department of Environmental Quality (ADEQ) has extended its High Pollution Advisory (HPA) for ozone in the Phoenix area to continue through Wednesday, May 6.

Maricopa County has implemented its ban on wood fire and commercial use of leaf blowers during the advisory.

ADEQ recommends that people limit outdoor activity while the HPA is in effect, especially children and adults with respiratory problems.

Ground level ozone forms when two types of pollutants—volatile organic compounds (VOCs) and nitrogen oxides (NOx)—react in sunlight. These pollutants come primarily from automobiles, but also from other sources including industries, power plants, and products, such as solvents and paints. Generally, the highest levels of ozone occur in the afternoon.

People most vulnerable to the impacts of air pollution include children, older adults, adults exercising outdoors, people with heart or lung disease and those suffering from asthma and bronchitis. Exposure can increase the number and severity of asthma attacks, cause or aggravate bronchitis or other lung disease and reduce the body’s ability to fight infection. Symptoms may include itchy eyes, nose, and throat, wheezing, coughing, shortness of breath, chest pain and upper respiratory issues.