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Writer's pictureGroup Against Smog & Pollution

UPDATED: Mon Valley Experiences Another Air Quality Exceedance, GASP Asks Allegheny Co. Health Dept.

Updated: Jun 7


By 9 a.m. Monday, concentrations of hydrogen sulfide (H2S) were so high at Allegheny County Health Department’s air quality monitor in North Braddock Borough that an exceedance of Pennsylvania’s 24-hour average was already guaranteed.


That makes 15 exceedances of the state standard so far this year at that site for H2S, which has a tell-tale rotten egg odor those in the Mon Valley (and folks downwind of it) endure all too often.


For those keeping track, there have also been 39 H2S exceedances at ACHD’s air quality monitor in Liberty Borough.


The frequency of these air quality exceedances is truly a shame and a burden on local residents. Even more shameful is the total silence from the Allegheny County Health Department.


“Monitoring air quality data and alerting residents when something isn’t right is a duty we take seriously,” GASP Executive Director Patrick Campbell said. “But we can only tell folks what the data say. We count on the health department to fill in the important details like the cause of these continually elevated levels of H2S and steps being taken to eliminate the issue.”


The simple fact is that air quality doesn’t have to be like this, and very recently wasn’t like this: ACHD air quality monitor data show that over the first seven weeks of 2021, H2S levels paled in comparison to what we’ve experienced since then.

What changed? We’d love to know. But the public is ill-equipped and lacks the expertise to determine those answers. ACHD is the sole party that has the capacity to resolve and address the issue.


ACHD is planning to deploy additional H2S monitoring as part of a wider air quality study in the Mon Valley but the results can’t come soon enough for residents sick and tired of the stench.

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