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UPDATED: Today Will Mark 54th H2S Exceedance of 2021 at Liberty Monitor; Abysmal Air Quality Returns

Updated: Sep 12, 2022

Editor’s Note: This blog was updated at 10:35 a.m. Wednesday, Dec. 22, 2021, to include information on an exceedance that occurred at North Baddock Tuesday. The associated chart was also updated.

By 7 a.m. Tuesday, social media and SmellPGH users were sounding the alarm about it being another stinky morning in and around the ‘Burgh. 

As complaints rolled in about the overwhelming odor and physical impacts they caused, AirNow.Gov showed AQI NowCast values at Allegheny County Health Department’s air quality monitor in Liberty borough peaking at 149, which is considered unhealthy for sensitive populations.

These complaints came in the wake of yet more exceedances of Pennsylvania’s 24-hour standard for hydrogen sulfide (AKA H2S AKA that rotten egg odor with which you may be all too familiar).

For those keeping track: Yesterday and today will mark the 53rd and 54th exceedances so far this year at the Liberty monitor. There was also an H2S exceedance at ACHD’s air quality monitor in North Braddock Borough Tuesday – the 18th so far this year at that location. 

We also want to note: It wasn’t just H2S that remained a concern Tuesday. Concentrations of fine particulate matter (PM2.5) were also elevated at the Liberty monitor during the early morning hours.

ACHD’s air quality forecast and daily dispersion report for Tuesday indicates that an inversion was expected to break after 10 a.m., after which PM2.5 and H2S levels should drop off. 

However, ACHD’s forecast also notes that “poor” and “very poor” atmospheric dispersion – the atmosphere’s ability to transport pollution away from its source – are expected this evening and overnight.

Our take: don’t be surprised if poor air quality returns after dark.

GASP remains concerned about the mounting number of H2S exceedances, what might be causing them, as well as ACHD’s continued silence regarding this public health, quality of life, and environmental justice issue.

“All we know is that the health department issued an enforcement action against U.S. Steel all the way back in April for H2S violations at its Clairton Coke Works plant. Since then, residents have suffered through 47 days on which concentrations exceeded regulatory limits,” GASP Executive Director Patrick Campbell said. 

He added:

“It’s unfortunate that demanding clean air for children, our seniors, and every human being in Allegheny County is considered an ‘extremist’ position by the Allegheny County Executive’s office. When it comes to the county’s public health, the buck ultimately stops with the Executive’s office, and it’s time for him to protect the residents he took an oath to serve.”

Editor’s Note: GASP will continue to monitor the data and provide updates both here and on social media – so stay tuned. In the meantime, here are two charts for folks who’d like to take a deeper dive into the data:

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