For the first time since 1971, the EPA has proposed revisions to the nitrogen dioxide air quality standard. The latest research on NO2 emissions shows that the molecule can lead to respiratory di sease, even when exposure is limited to 30 minutes. The EPA proposes:

  • Establishing a one-hour NO2 standard at a level between 80 – 100 parts per billion (ppb). The Agency is taking comment on alternative levels for the 1-hour standard down to 65 ppb and up to 150 ppb
  • Retaining the current annual average NO2 standard of 53 ppb
  • Adding NO2 monitoring within 50 meters of major roads in cities with at least 350,000 residents
  • Continuing monitoring area-wide NO2 concentrations in cities with at least 1 million residents. (Source: EPA, June 29, 2009).

    Contact: Cathy Milbourn, EPA, (202) 564-4355,,