NAAQS Compliance
- Please refer to the EPA's Reviewing National Ambient Air Quality Standards (NAAQS) website for additional information.
| Pollutant | Primary/Secondary | Averaging Time | Level | Form |
|---|---|---|---|---|
| Carbon Monoxide (CO) | primary | 8 hours | 9 ppm | Not to be exceeded more than once per year |
| Carbon Monoxide (CO) | primary | 1 hour | 35 ppm | Not to be exceeded more than once per year |
| Lead (Pb) | primary and secondary | rolling 3 month average | 0.15 µg/m3 (1) | Not to be exceeded |
| Nitrogen Dioxide (NO2) | primary | 1 hour | 100 ppb | 98th percentile of 1-hour daily maximum concentrations, averaged over 3 years |
| Nitrogen Dioxide (NO2) | primary and secondary | 1 year | 53 ppb (2) | Annual Mean |
| Ozone (O3) | primary and secondary | 8 hours | 0.070 ppm (3) | Annual fourth-highest daily maximum 8-hour concentration, averaged over 3 years |
| Particle Pollution (PM2.5) | primary | 1 year | 9.0 µg/m3 | Annual mean, averaged over 3 years |
| Particle Pollution (PM2.5) | secondary | 1 year | 15.0 µg/m3 | Annual mean, averaged over 3 years |
| Particle Pollution (PM2.5) | primary and secondary | 24 hours | 35 µg/m3 | 98th percentile, averaged over 3 years |
| Particle Pollution (PM10) | primary and secondary | 24 hours | 150 µg/m3 | Not to be exceeded more than once per year on average over 3 years |
| Sulfur Dioxide (SO2) | primary | 1 hour | 75 ppb (4) | 99th percentile of 1-hour daily maximum concentrations, averaged over 3 years |
| Sulfur Dioxide (SO2) | secondary | 3 hours | 0.5 ppm | Not to be exceeded more than once per year |
(1) In areas designated nonattainment for the Pb standards prior to the promulgation of the current (2008) standards, and for which implementation plans to attain or maintain the current (2008) standards have not been submitted and approved, the previous standards (1.5 µg/m3 as a calendar quarter average) also remain in effect.
(2) The level of the annual NO2 standard is 0.053 ppm. It is shown here in terms of ppb for the purposes of clearer comparison to the 1-hour standard level.
(3) Final rule signed October 1, 2015, and effective December 28, 2015. The previous (2008) O3 standards are not revoked and remain in effect for designated areas. Additionally, some areas may have certain continuing implementation obligations under the prior revoked 1-hour (1979) and 8-hour (1997) O3 standards.
(4) The previous SO2 standards (0.14 ppm 24-hour and 0.03 ppm annual) will additionally remain in effect in certain areas: (1) any area for which it is not yet 1 year since the effective date of designation under the current (2010) standards, and (2)any area for which an implementation plan providing for attainment of the current (2010) standard has not been submitted and approved and which is designated nonattainment under the previous SO2 standards or is not meeting the requirements of a SIP call under the previous SO2 standards (40 CFR 50.4(3)). A SIP call is an EPA action requiring a state to resubmit all or part of its State Implementation Plan to demonstrate attainment of the required NAAQS.
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