National Ambient Air Quality Standards (NAAQS) | Department of Environmental Conservation

The Clean Air Act, which was last amended in 1990, requires EPA to set National Ambient Air Quality Standards for pollutants considered harmful to public health and the environment. The Clean Air Act established two types of national air quality standards. Primary standards set limits to protect public health, including the health of “sensitive” populations such as asthmatics, children, and the elderly. Secondary standards set limits to protect public welfare, including protection against decreased visibility, damage to animals, crops, vegetation, and buildings.

The EPA Office of Air Quality Planning and Standards (OAQPS) has set National Ambient Air Quality Standards for six principal pollutants, which are called “criteria” pollutants. They are listed below. Units of measure for the standards are parts per million (ppm) by volume, parts per billion (ppb) by volume, milligrams per cubic meter of air (mg/m3), and micrograms per cubic meter of air (ug/m3). 

National Ambient Air Quality Standards (1/3/22)
Pollutant
Standard Value
Standard Type
Carbon Monoxide
 
 
8-Hour Average
9 ppm 
Primary
1-Hour Average
35 ppm 
Primary
Nitrogen Dioxide (NO2)
 
 
1-Hour Average
100 ppb
Primary 
1-Year Average

53 ppb

Primary &

Secondary

Ozone (O3)
 
 
8-Hour Average
0.070 ppm
Primary & Secondary
Lead (Pb)
 
 
Rolling Three Month Average 
0.15 µg/m3
Primary & Secondary
Fine Particulate (PM2.5)
 
 
1-Year Average

12 µg/m

3

Primary 
1-Year Average

15 µg/m

3

Secondary

24-Hour Average

35 µg/m

3

Primary & Secondary

Particulate (PM10)
 
 
24-Hour Average
150 µg/m3

Primary & Secondary

Sulfur Dioxide (SO2)
 
 
1-Hour Average
75 ppb  
Primary
3-Hour Average
0.50 ppm 
Secondary