Ambient Air Quality NEPM

Ambient Air Quality NEPM

In June 1998, the NEPC made the Ambient Air Quality NEPM which set uniform standards for ambient air quality. The standards in the NEPM for ambient air quality are listed below. The NEPM was varied to add an advisory reporting standard for PM2.5.

Please note that ambient air does not include indoor air.

The Ambient Air Quality NEPM is currently under review.

Standards and Goal

Pollutant
Averaging period
Maximum concentration
Goal within 10 years maximum allowable exceedences
Carbon monoxide 8 hours 9.0 ppm 1 day a year
Nitrogen dioxide 1 hour
1 year
0.12 ppm
0.03 ppm
1 day a year
none
Photochemical oxidants (as ozone) 1 hour
4 hours
0.10 ppm
0.08 ppm
1 day a year
1 day a year
Sulfur dioxide 1 hour
1 day
1 year
0.20 ppm
0.08 ppm
0.02 ppm
1 day a year
1 day a year
none
Lead 1 year 0.50 µg/m3 none
Particles as PM10 1 day 50 µg/m3 5 days a year