Exceptional Event Documentation

The Kansas Department of Health and Environment, Bureau of Air, operates an ambient air monitoring network that measures concentrations of various air pollutants. Other environmental agencies operate similar networks throughout the United States. When an event causes an exceedance of an ambient standard, the event may be excluded from compliance calculations. There is a specific process for excluding an event, which includes public notice of each request. This notice provides an opportunity for public review and comment on the supporting documentation.

Following the opportunity for public comment, the Department submits this information to the United States Environmental Protection Agency (EPA) for their review and approval. If the EPA concurs that the appropriate flagged data were affected by an Exceptional Event, data generated by the state's monitors affected by the Exceptional Event are not used to determine compliance with the National Ambient Air Quality Standards (NAAQS).

Contact information is provided below for questions about this process or about a specific Exceptional Event proposal.

What Is an Exceptional Event?

According to federal regulations: "An exceptional event is defined as an event that affects air quality, an event that is not reasonably controllable or preventable, is an event caused by human activity that is unlikely to recur at a particular location or a is a natural event, and is determined by the EPA to be an exceptional event."

Exceptional Events may include, but are not limited to, prescribed burnings, wildfires, and large firework displays.

Exceptional Events do not include stagnation of air masses or meteorological inversions, meteorological events involving high temperature or a lack of precipitation, or air pollution relating to source noncompliance.

To summarize, an Exceptional Event is one that:

  • Affects air quality
  • Is not reasonably controllable or preventable
  • Is an event that is caused by human activity that is unlikely to recur at a particular location, or is a natural event
  • Is determined by the Administrator of the EPA through the process established in the rule to be an exceptional event

KDHE Exceptional Events Documents