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Exceptional Event Demonstrations for Particulate Matter

Demonstrations supporting the proposed exceptional events for particulate matter data.

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 TCEQ's proposed exceptional event flags.

EPA Regulations and Guidance

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

Current Exceptional Event Demonstration Proposal

El Paso, Nueces, and Harris County PM10 Demonstration for Three Days in 2021

Public Comment Period: Closed

TCEQ posted this demonstration for written public comment on Jun. 27, 2023. We will submit all comments received or postmarked by 5:00 p.m. CDT on Jul. 31, 2023, to the EPA along with the final demonstration. No public hearing will be held for this action.

Previous Exceptional Event Demonstrations

El Paso Demonstrations

December 23, 2020 PM10 Exceptional Event

2017-2018 PM10 Exceptional Events

2010-2012 PM2.5 and PM10 Exceptional Events

Houston Clinton Monitor Demonstrations (English Only)

2012 Exceptional Events

2011 Exceptional Events

2010 Exceptional Events

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