Exceptional Events Elements of an Effective Demonstration. Darren Palmer US EPA Region 4. Exceptional Events Rule The Basics. Sets criteria and process for EPA to agree to exclude event-influenced data when determining NAAQS compliance and design values.
Exceptional EventsElements of an Effective Demonstration
US EPA Region 4
The Exceptional Event DemonstrationThe Four-Part Test [§ 50.14(c)(3)(iii)]
Observed PM2.5 concentration over historical 95th percentile
This is the only scenario in which data may be excluded
The orange line approximates what the observed PM2.5 concentration would have been “but for” the event.