Mon Valley Episode Rule

In September 2021, the Mon Valley Air Pollution Episode Rule was added to "Article XXI - Air Pollution Control Regulations" to respond to weather-related inversions in the Mon Valley, which can result in episodes of high levels of particulate matter pollution (PM_2.5).

The rule has the health department monitor weather forecasts for conditions that lead to an episode. When weather conditions are likely to exceed acceptable levels for the Mon Valley, companies impacted by the rule must execute plans, submitted and approved by the Health Department, that will reduce their emissions.

The rule applies to sources within or near the following municipalities: Braddock, Braddock Hills, Chalfant, Clairton, Dravosburg, Duquesne, East McKeesport, East Pittsburgh, Elizabeth Borough, Elizabeth Township, Forest Hills, Forward, Glassport, Jefferson Hills, Liberty, Lincoln, McKeesport, Munhall, North Braddock, North Versailles, Port Vue, Rankin, Swissvale, Turtle Creek, Versailles, Wall, West Elizabeth, West Mifflin, White Oak, Wilkins, Wilmerding and Whitaker.

Notifications and alerts will be sent out using Allegheny Alerts. The Mon Valley Episode Rule Regulation governs this process. 

Facilities Subject to the Mon Valley Episode Rule

The following facilities are subject to the new Mon Valley Air Pollution Episode Rule(PDF, 405KB), which requires them to provide written Mitigation Plans. The status of those plans is shown below.

Facilities Previously Subject to the Mon Valley Episode Rule (No Longer Operating)

(page updated 7/29/2026)