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  2. Nitrogen Dioxide (NO2) Pollution

Ambient Nitrogen Dioxide Monitoring Requirements

Ambient Nitrogen Dioxide Monitoring Requirements
Basic Information
Code of Federal Regulations Citations
  • 40 CFR Part 58
Docket Numbers
  • EPA-HQ-OAR-2015-0486

On this page:

  • Rule Summary
  • Rule History
  • Additional Resources

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 (pdf) (272 KB)

05/16/2016 - Proposed Rule (pdf) (265 KB)

Additional Resources

Fact Sheets: Final and Proposed Rules

Related Rules

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

Nitrogen Dioxide (NO2) Pollution

  • Nitrogen Dioxide Basics
  • Setting & Reviewing NO2 Standards
  • Primary NO2 Standard Regulatory Actions
  • Secondary NO2 and SO2 Standard Regulatory Actions
  • Implementing NO2 Standards
  • Primary NO2 Standard Implementation Actions
  • Implementation Data and Reports
  • Other Criteria Air Pollutants
Contact Us about Nitrogen Dioxide (NO2) Pollution
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on May 8, 2025
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