Answer;
-Six
The National Ambient Air Quality Standards (NAAQS) are maximum allowable levels for six harmful pollutants. sixteen six sixty ten.
Explanation;
-The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for six common air pollutants (also known as "criteria air pollutants. These pollutants are found all over the U.S. They can harm your health and the environment, and cause property damage.
-These pollutants are particulate matter, photochemical oxidants, carbon monoxide, sulfur oxides, nitrogen oxides and lead. They are called criteria air pollutants because its sets NAAQS for them based on the criteria, which are characterizations of the latest scientific information regarding their effects on health or welfare.
