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Nitrogen Dioxide (NO2) Pollution

Ambient Nitrogen Dioxide Monitoring Requirements

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Rule Summary

EPA removed the requirement to install near-road nitrogen dioxide (NO2) monitoring stations in Core Based Statistical Areas (CBSAs) having populations between 500,000 and 1 million.  Under the original monitoring requirements, these monitors were due to be installed and operational by January 1, 2017. 

Current near road monitoring shows that air quality levels, in urban areas with larger populations, are well below the National Ambient Air Quality Standards for NO2 issued in 2010. Based on this information, EPA does not anticipate near road NO2 concentrations to be above the health-based national air quality standards in smaller urban areas.

This action does not change the requirements for near-road NO2 monitors in more populated areas, area-wide NO2 monitoring, or monitoring of NO2 in areas with susceptible and vulnerable populations. 

Rule History

12/30/2016 - Final Rule

05/16/2016 - Proposed Rule

Additional Resources

Fact Sheets: Final and Proposed Rules

Related Rules

2010 Primary National Ambient Air Quality Standards (NAAQS) for Nitrogen Dioxide