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.
| 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 |
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