Hazardous air pollutants are substances released into the air by industries, vehicle emissions, agricultural activities and other sources that may threaten human health. People are most likely to be exposed to HAPs by breathing indoor or outdoor air, but they can also come into contact with chemicals that have settled out of the air and been absorbed by soil and water.

Respiratory problems, such as bronchitis and asthma, are the most obvious health effects related to HAPs exposure, but HAPs also can damage the liver and nervous system and, in some cases, can cause cancer. Not everyone who is exposed to HAPs will develop harmful health effects; it depends on the amount and duration of exposure.

Hazardous Air Pollutant Co-Operative Study
ADEQ along with three local tribes, Maricopa and Pima counties, and EPA have joined resources to assess hazardous air pollutants in the Phoenix area.

Arizona Ambient Air Quality Guidelines
A listing of the acceptable concentration levels for hazardous air pollutants that are regulated by the State of Arizona.

Modeling Guidelines