Exceptional Events Rule (EER)

The EER was promulgated in March 2007 and is a means for States to exclude air quality monitoring data from regulatory determinations related to exceedances or violations of the National Ambient Air Quality Standards (NAAQS) and avoid designating an area as nonattainment, re-designating an area as nonattainment, or reclassifying an existing nonattainment area to a higher classification if a State adequately demonstrates that an exceptional event has caused an exceedance or violation of a NAAQS.

EPA defines an 'exceptional event' to mean an event that:

  1. Affects air quality
  2. Is not reasonably controllable or preventable
  3. Is an event caused by human activity that is unlikely to recur at a particular location, or a natural event
  4. Is determined by the EPA through the process established in these regulations to be an exceptional event

The EER addresses both wildfire and prescribed fire, where in the case of prescribed fire, EPA recognizes the essential ecological role of fire to an ecosystem.

Sources: US Federal Register. 2007. United States Environmental Protection Agency. 40 CFR Parts 50 and 51. Treatment of Data Influenced by Exceptional Events; Final Rule. Federal Register Vol. 72, Number 55. Thursday, March 22 2007. Available at http://www.epa.gov