Johnie Perryman is 79 years old and lives in Clairton, near U.S. Steel’s Clairton Coke Works. He says the air this month has been pretty bad.
“It’s been smelling like rotten eggs sometimes. And sometimes it smells like something like wood is on fire,” he said.
Perryman has a heart condition, and when the air gets bad in Clairton, he can feel it in his chest.
“I can smell it inside of my house. And not only can I smell it inside of my house, it wakes me up, my heart starts palpitating, starts beating and I wake up and I put a mask on,” he said.
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That rotten egg smell that is seeping inside Perryman’s house is hydrogen sulfide from the Coke Works. The plant is the state’s largest source of hydrogen sulfide, and the county has found the plant is ‘entirely’ responsible for the county’s hydrogen sulfide problem.
Since the weather turned colder this October, levels of hydrogen sulfide and soot have surged in Allegheny County. Hydrogen sulfide levels measured at the county’s Liberty-Clairton air monitor have exceeded state standards a dozen times already this month, according to data compiled by the Group Against Smog and Pollution.
Those surges have been brought on by strong temperature inversions – a weather pattern that traps pollution close to the ground.
Albert Presto, associate research professor of mechanical engineering at Carnegie Mellon University, says inversions happen when the air near the ground cools off – typically on a clear, crisp night. When that happens, a warm layer above the ground keeps pollution close to the ground.
“You can think of it exactly as a lid, and that lid can go up and can go down,” Presto said.
When the lid is lowered, the more air pollution stays on the ground. Presto said the problem is worse in mill towns like Clairton along the Monongahela River, with lots of industrial pollution.
“Especially in the Mon River Valley, there are a bunch of (pollution) sources, it’s already at the bottom of the valley, and then you put this inversion on top, and so you’re going to get really high concentrations (of pollution) there,” he said.
Last year, Allegheny County passed a new rule that was supposed to remedy the problem. It allowed the health department to make big polluters in the Mon Valley follow a set of plans to lower emissions during inversions. For U.S. Steel, that means limiting production at Clairton by extending coking times.
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Then on October 10, an inversion was forecast. The county issued a watch – basically an alert – but no warning, which would have made companies implement their plans to cut pollution. Geoff Rabinowitz, the county health department’s deputy director of environmental health, said the county only calls for a warning if air problems are forecast to last more than 24 hours
“Based upon that forecast, we did not have information that that was looking like it would extend beyond the 24 hour time period,” Rabinowitz said.
Even though no warning was issued, a U.S. Steel spokesperson said in an email the company voluntarily set in motion its approved action plan on that day. But air pollution levels still spiked, leading the state Department of Environmental Protection to issue an unhealthy air warning.
The county could try to tighten its standards in the future, according to Rabinowitz. He said the rule has s only been in place for a year. The county has issued four warnings and three watches since last November.
“As we get data, as we can assess things, we are open to looking at, you know, our rule. I can’t say what direction, what the outcome was going to be because we haven’t begun to do that,” Rabinowitz said.
Ned Mulcahy of the Group Against Smog and Pollution says one problem with the rule is that it is tied to levels of fine particulate matter – PM 2.5. As those concentrations go up, usually other pollutants, like hydrogen sulfide do too. But not always. So if hydrogen sulfide levels go up but not PM 2.5, the county can’t issue a warning.
Overall though, he hopes that the rule will work to curb inversion-related pollution events.
“I think a lot of people put effort into writing that rule to be protective,” Mulcahy said. “But, no, I’m not sure how it will really work. We’ll have to sort of see.”
Changing the rule wouldn’t happen overnight – creating the current rule took the county health department nearly two years to develop.
This story is produced in partnership with StateImpact Pennsylvania, a collaboration among The Allegheny Front, WPSU, WITF and WHYY to cover the commonwealth's energy economy.