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Writer's pictureGroup Against Smog & Pollution

<UPDATED> Allegheny Co. Health Department Issues Mon Valley Air Pollution Warning for Tuesday

Updated: Sep 9, 2022


The Liberty-Clairton area woke up to unhealthy air quality again Tuesday, with EPA’s NowCast AQI soaring to 183 and hourly monitor data showing elevated levels of PM2.5, hydrogen sulfide, and sulfur dioxide at the Liberty monitor.

HEADS UP: Liberty-Clairton waking up to horrific air quality today. Current AQI is listed as 183 by @AIRNow (CodeRed unhealthy for all) & @HealthAllegheny monitor data show sky-high concentrations of both PM2.5 and H2s at the Liberty monitor. Please take care if you’ll be out. pic.twitter.com/9RDdwK4hxP — GASP (@GASPPgh) March 15, 2022

By 8:20 a.m., the Allegheny County Health Department issued the following through the Allegheny Alert system and through social media:

Mon Valley Air Pollution Warning Issued An Air Pollution Warning has been issued for the Mon Valley for today and all of tomorrow. The 24-hour PM2.5 standard for the Mon Valley has been exceeded at an official monitoring station in the Mon Valley and is likely to continue. pic.twitter.com/EpTUuzMymi — Allegheny County Health Department (@HealthAllegheny) March 15, 2022

An Air Pollution Warning has been issued for the Mon Valley for the remainder of today and all of tomorrow. The 24-hour PM2.5 standard for the Mon Valley has been exceeded at an official monitoring station in the Mon Valley and is likely to continue.


Young children, the elderly, and those with respiratory problems, such as asthma, emphysema, and bronchitis, are especially vulnerable to the effects of air pollution and should limit outdoor activities during this time.


Companies most significantly contributing to particulate pollution in the Mon Valley region are required to temporarily reduce particulate emissions.


For those who might need a refresher on the Mon Valley Air Pollution Episode Rule, check out our FAQ here.


Editor’s Note: At 9:30 a.m. the state Department of Environmental Protection (DEP) issued a Code Orange Action Day for the Liberty-Clairton area for particulate matter (PM2.5).

DEP Declares Code Orange Air Quality Action Day for Fine Particulate Matter for Tuesday, March 15, 2022, in the Liberty-Clairton area in Allegheny County: https://t.co/XfzN20i6K3 pic.twitter.com/VNN5vW4kC1 — PA Department of Environmental Protection (@PennsylvaniaDEP) March 15, 2022

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