Ambient Standards

National Ambient Air Quality Standards (NAAQS)
Pollutant Average Time Maximum Allowed
Particulate Matter
PM2.5
24 Hour
Annual Mean (Primary)
Annual Mean (Secondary)
35 ug/m3
12 ug/m3
15 ug/m3
Particulate Matter
PM10
24 Hour 150 ug/m3
Nitrogen Dioxide 1 Hour
Annual Mean
100 ppb
53 ppb
Ozone O3 8 Hour 70 ppb
Sulfur Dioxide SO2 1 Hour (Primary)
3 Hour (Secondary)
75 ppb
0.5 ppm
Carbon Monoxide 1 Hour
8 Hour
35 ppm
9 ppm
*U.S. EPA National Ambient Air Quality Standards (NAAQS)
Wyoming Ambient Air Quality Standards (WAAQS)
Pollutant Average Time Maximum Allowed
Particulate Matter
PM2.5
24 Hour
Annual Mean (Primary)
Annual Mean (Secondary)
35 ug/m3
12 ug/m3
15 ug/m3
Particulate Matter
PM10
24 Hour
Annual Mean
150 ug/m3
50 ug/m3
Nitrogen Dioxide 1 Hour
Annual Mean
100 ppb
53 ppb
Ozone O3 8 Hour 70 ppb
Sulfur Dioxide SO2 1 Hour 75 ppb
Carbon Monoxide 1 Hour
8 Hour
35 ppm
9 ppm
* Wyoming Air Quality Standards and Regulations (WAQSR), Chapter 2, Ambient Standards. [Last Updated October 13, 2015]