Definitions for "Air toxics"
A category of substances in the air that are known or suspected of causing cancer or other health problems in humans, and for which a National Ambient Air Quality standard (NAAQS) does not exist (i.e. excluding ozone, carbon monoxide, PM-10, sulfur dioxide, nitrogen oxide).
gaseous, aerosol or particulate contaminates present in trace amounts in ambient air, with characteristics (toxicity, persistence) which make them a hazard to human health, plant and animal life.
Toxic air pollutants defined under Title II of the CAA, including benzene, formaldehyde, acetaldehyde, 1-3 butadiene and polycyclic organic matter (POM). Benzene is a constituent of motor vehicle exhaust, evaporative and refueling emissions. The other com-pounds are exhaust pollutants.