How Bad has Air Quality Been? H2S Was Below PA Standard For Only 3 Hours This Week



GASP crunched the numbers and can tell you definitively that in the Mon Valley (and downwind of it) the stench has been UNRELENTING this week.


As we reported last week – and sadly all too often this week – the 24-hr average concentration of hydrogen sulfide at Allegheny County Health Department’s air quality monitor in Liberty Borough first exceeded the state standard on Oct. 5 during the 8 p.m.-9 p.m. EDT hour.


Since then (through 9 a.m. EDT today, Friday, Oct. 14), the rolling 24-hr H2S average has only been below the Pennsylvania standard for 32 out of 205 hours. That is only 16 percent of the time over 8.5 days.


Sticking with just this week, the 24-hour H2S average at Liberty has only been below the standard for 3 hours since 3 a.m. EDT Sunday.

As for exceedances of the 24-hr standard overall, today makes nine of the past 10 days and six in a row.

And that’s to say nothing of the insane one-hour H2S values last week. Concentrations exceeded Pennsylvania’s one-hour standard at the Liberty monitor for the first time since 2015. Here’s a little perspective on that: H2S levels exceeding the state one-hour standard have only occurred nine times in the past 20 years, according to ACHD monitor data.

Or – keeping with today’s “hourly” theme – H2S levels last week were among the 11 worst hourly concentrations out of more than 180,000 hours since 2001.

GASP remains concerned about these sky-high H2S concentrations. That’s because exposure to the levels of the colorless gas (that’s recognizable by its rotten egg odor) we see in the Mon Valley can cause irritation to the eyes, nose, or throat as well as headaches, poor memory, tiredness, and balance problems. It may also cause difficulty in breathing for some asthmatics, according to the Agency for Toxic Substances and Disease Registry.

If you’re wondering, “What is the source of all this H2S?” a recent ACHD study concluded it’s none other than U.S. Steel. For those who might have missed it, the 31-page study found that years’ worth of H2S exceedances in the Mon Valley “can be attributed entirely to emissions from US Steel’s Clairton coking facility.”

Days after the study was published, ACHD issued a $1.8 million enforcement order against U.S. Steel over the H2S emissions issue. The company appealed the order and the case is ongoing.

Meanwhile, other than a pair of barebones public alerts issued last week, our health department officials have remained silent. Since announcing at 11:31 a.m. last Friday in an Allegheny Alert that “levels were expected to decrease” health leaders have said nothing about this continued public health and quality of life issue.

So today GASP is AGAIN calling on ACHD for a substantive public update addressing what actions it is taking to put a stop to this issue.

“People continue to suffer and every day they don’t hear from Allegheny County Health Department, the more public trust is eroded,” GASP Executive Director Patrick Campbell said. “We’ve said it before and it bears repeating now: This has been a failure of leadership and residents deserve better.”


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