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Exceptional Event Demonstrations for Particulate Matter

Explanation of exceptional event flags. Demonstrations supporting the proposed exceptional event flags for particulate matter data.

(Esta página en español. / This page in Spanish.)

About Exceptional Events


Exceptional events are unusual or naturally occurring events that affect air quality and are not reasonably controllable or preventable. Wildfires are an example.

How They Affect Monitoring Data

States can request that the United States Environmental Protection Agency (EPA) exclude air quality monitoring data affected by an exceptional event from determining if an area met an air quality health standard . The demonstration documents below were developed in support of the TCEQ's proposed exceptional event flags.

EPA Regulations and Guidance

Exceptional event regulations and guidance are provided on EPA's Treatment of Air Quality Data Influenced by Exceptional Events website.

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