The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) The six pollutants are carbon monoxide, lead, ground-level ozone, nitrogen dioxide, particulate matter, and sulfur dioxide.

The Clean Air Act requires the U.S. EPA to regulate emissions of air pollutants that are hazardous to human health or the environment, called hazardous air pollutants (HAPs) . The regulations are known as National Emission Standards for Hazardous Air Pollutants (NESHAP).

The National Emission Standards for Hazardous Air Pollutants (NESHAP) is an Environmental Protection Agency (EPA) standard that is applicable within the United States to the emissions of hazardous air pollutants produced by corporations, institutions and at Agencies at all levels of government.

Fact Sheet: Clean Air Act Section 112(r): Accidental Release Prevention / Risk Management Plan Rule. This factsheet describes how EPA is required to publish regulations and guidance for chemical accident prevention at facilities that pose the greatest risk of harm from accidental releases.