top of page

Rotten Egg Odor Returns Wednesday as Mon Valley Experiences 3rd 2022 Exceedance of PA’s Hydrogen Sul

This was one of the complaints filed with CMU’s SmellPGh app Wednesday.




Wednesday marked the third time so far this year that concentrations of hydrogen sulfide (or H2S, an air pollutant known by its rotten-egg odor) exceeded Pennsylvania’s 24-hour average standard at Allegheny County Health Department’s air quality monitor in Liberty Borough.

For those trying to keep track: H2S concentrations at the Liberty monitor exceeded the Pennsylvania 24-hour average standard 54 times last year – which was more than twice 2020’s numbers.

But that’s not all: There were 18 other such exceedances at Allegheny County Health Department’s air quality monitor in North Braddock Borough last year.

“Despite the regularity with which these exceedances occur and our regular calls to action asking ACHD to better communicate the issue with residents – Chief Operating Officer Patrick Dowd and health department leadership have refused to acknowledge the issue publicly,” GASP Executive Director Patrick Campbell lamented. “We don’t know why ACHD has refused to be more transparent on this issue but do know that their silence is speaking volumes to residents.”

Here’s what we *do* know: That ACHD issued an H2S-related enforcement action against U.S. Steel’s Clairton Coke Works in April (as well as an associated press release), but no other details have since been provided to the public.

So for the third of what may be many times this year, GASP is again asking Mr. Dowd and his leadership team at the health department to take seriously these H2S exceedances and better communicate with the people ACHD is duty-bound to protect – and to take swift action to ensure ACHD develops a communications strategy that better informs residents about H2S exceedances as well as short-term bouts of unhealthy air that threaten public health but do not meet the criteria for a Mon Valley Air Pollution Episode alert.



“This is not only a quality of life issue,” Campbell said. “Exposure to hydrogen sulfide can cause irritation to the eyes, nose, or throat, as well as breathing problems, headaches, and fatigue. Helping residents mitigate exposure should be a no-brainer.”

Editor’s Note: GASP testified before the Allegheny County Board of Health earlier this month to request more robust communications around air quality issues. You can read all about that here.

bottom of page