Nitrogen Dioxide Designations

Nitrogen Dioxide Designations Regulatory Actions

This page contains a list of regulatory actions and correspondence related to the 2010 NO2 standard.

EPA Completes 2010 NO2 Standard Designations
January 20, 2012 – Based on the most recent air quality monitoring data (2008-2010), EPA has designated all areas of the country as unclassifiable/attainment.

EPA Strengthens NO2 National Ambient Air Quality Standard (NAAQS)
January 22, 2010 - EPA is establishing a new 1-hour standard at a level of 100 ppb, based on the 3-year average of the 98th percentile of the yearly distribution of 1-hour daily maximum concentrations, to supplement the existing annual standard.