Treatment of Air Quality Monitoring Data Influenced by Exceptional Events
December 19, 2024 – EPA has developed a new screening-level modeling dataset called Expedited Modeling of Burn Events Results (EMBER). EPA plans to hold a webinar on Tuesday, January 14 at 1:00 pm EST to present EMBER and provide a demonstration of the web-based tool.
November 7, 2024 – EPA has developed a new prescribed fire template for fires potentially impacting air concentrations of fine particulate matter (PM2.5), as well as an updated frequently asked questions document. Both resources can also be found on the Exceptional Events Rule and Supporting Guidance Documents page.
- Demonstration Template for Prescribed Fires Occurring on Wildland(s) that May Influence Fine Particulate Matter Concentrations (docx)
- Updated Exceptional Events Rule FAQs (pdf)
April 30, 2024 – EPA has developed three products to improve and support an efficient process for demonstrating exceptional events impacting air concentrations of PM2.5.
- PM2.5 Wildland Fire Exceptional Events Tiering Document (pdf)
- See Data Visualization Tools
- Prescribed Fire Demonstration
- January 11, 2024 Webinar
Exceptional events are unusual or naturally occurring events that can affect air quality but are not reasonably controllable using techniques that tribal, state or local air agencies may implement in order to attain and maintain the National Ambient Air Quality Standards (NAAQS). Exceptional events may include wildfires, high wind dust events, prescribed fires, stratospheric ozone intrusions, and volcanic and seismic activities.
The Exceptional Events Rule
In September of 2016, the Environmental Protection Agency (EPA) finalized revisions to the Exceptional Events Rule to establish criteria and procedures for use in determining if air quality monitoring data has been influenced by exceptional events. The rule:
- Applies to all exceptional event types and all NAAQS.
- Ensures that air quality measurements are properly evaluated and characterized with regard to their causes.
- Identifies reasonable actions that state, local and tribal air quality agencies should take to address the air quality and public health impacts caused by these types of events.
- Avoids imposing unreasonable planning requirements on air quality agencies related to violations of the NAAQS due to exceptional events.
- Ensures that the use of air quality data, whether afforded special treatment or not, is subject to full public disclosure and review.
The 2016 Exceptional Events Rule revises and replaces the 2007 Exceptional Events Rule to address issues raised by stakeholders and to increase the administrative efficiency of the Exceptional Events Rule criteria and process.
April 2022: Additional Areas Subject to Mitigation Plan Requirements Under the Exceptional Events Rule
Example Demonstrations and EPA Responses Prepared under the 2016 Exceptional Events Rule
Electronic Submission of Exceptional Events Demonstrations and/or Mitigation Plans
EPA Exceptional Events Contact:
Gobeail McKinley
U.S. EPA, Office of Air Quality Planning and Standards
Email: McKinley.Gobeail@epa.gov
919-541-5246