What are the National Ambient Air Quality Standards?

The National Ambient Air Quality Standards (NAAQS) are parameters set out by the United States Environmental Protection Administration (USEPA or EPA) to assess the quality of outdoor air. Communities that exceed the parameters have a air quality problem that must be addressed. There are a variety of ways communities can work to make their air cleaner, ranging from passing legislation to limit pollution to encouraging citizens to curtail activities that can lead to declines in air quality.

The EPA is given the authority to set the National Ambient Air Quality Standards under the Clean Air Act, a landmark piece of legislation passed in 1963 to address pollution in the United States. It was revised in 1970 and again in 1990 to address evolving environmental issues. Under the Clean Air Act, the EPA is responsible for setting standards and monitoring them, as well as issuing advisories about air quality for the benefit of members of the public.

Six known pollutants are tracked with the National Ambient Air Quality Standards: ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide, lead, and carbon dioxide. In addition, the EPA also monitors levels of particulates in the air. These pollutants pose a threat to humans, as well as environmental health and many are generated through human activities, such as operating motor vehicles. When they combine with environmental pressures like air masses that press pollutants down on communities instead of allowing them to disperse, they can pose a significant and immediate health threat.

There are two aspects to the National Ambient Air Quality Standards. The Primary Standard is focused on the levels of pollutants that are safe for human health, including vulnerable people, such as older adults, children, and people with respiratory conditions like asthma. The Secondary Standards are concerned with public welfare issues like visibility on the roads and damage to crops. Using air quality monitors in communities across the United States, the EPA keeps track of pollutant levels and issues warnings when appropriate.

When air quality is extremely bad, the EPA may issue advisories to alert vulnerable members of the public to the risks. The goal of the National Ambient Air Quality Standards is to eventually prevent the occurrence of many bad air days by setting standards for communities and holding them accountable. Since the passage of the Clean Air Act, pollution in the United States has declined radically and the number of communities that cannot comply with the standards is also dropping.